Local Roads Bridge Replacement Prioritization Database (BRPD) Program

By

Thomas C. Grimes, P.E., Fred M. Gauntt III, and James S. Davidson, Ph.D. Department of Civil and Environmental Engineering

The University of Alabama at Birmingham Birmingham, Alabama

Prepared by

UTCA University Transportation Center for Alabama

The University of Alabama, The University of Alabama at Birmingham, and The University of Alabama in Huntsville

UTCA Report Number 00219 June 2001

ii

Technical Report Documentation Page 1. Report No FHWA/CA/OR-

2. Government Accession No. 3. Recipient Catalog No.

5. Report Date June 2001

4. Title and Subtitle Local Roads Bridge Replacement Prioritization Database (BRPD) Program

6. Performing Organization Code

7. Authors Grimes, Thomas C., P. E., Fred M. Gauntt, E. I., and James S. Davidson, Ph.D.

8. Performing Organization Report No. UTCA Report 00219

10. Work Unit No.

9. Performing Organization Name and Address Department of Civil & Environmental Engineering The University of Alabama at Birmingham 1075 13th Street South Birmingham, AL 35294-4440

11. Contract or Grant No. DTRS98-G-0028

13. Type of Report and Period Covered Final Report/ 01/01/00-12/3100

12. Sponsoring Agency Name and Address University Transportation Center for Alabama The University of Alabama P.O. Box 870205 Tuscaloosa, AL 35487-0205

14. Sponsoring Agency Code

15. Supplementary Notes 16. Abstract

Bridge inspection and replacement prioritization are vital tools used to compete for the finite pools of federal, state, and local government funds. Without these funds, an agency’s ability to manage, repair, rehabilitate, and replace aging bridge infrastructure is greatly hampered. To date, the development of inspection and replacement prioritization research, tools, and technology has been concentrated on the larger problem of the National Bridge Inventory System (NBIS). As a result, the growing problem of deteriorating structures that are not directly eligible for Federal Aid Bridge Replacement funds or state bridge funds has been greatly ignored. However, there is a growing need for investigation and application of bridge database inventory, bridge system networking, and bridge replacement prioritization systems for bridges that do not qualify as NBIS structures. Useful bridge inspection tools, techniques, and prioritization processes are given herein that are similar to those used in the existing Alabama Bridge Inventory Management System and other NBIS inspection and prioritization systems. Simplified reporting and streamlined prioritizing encourage the voluntary incorporation of this system into a local government’s existing bridge inspection and replacement program. The inspection and prioritization procedures herein follow general NBIS recommendations for defining a bridge’s sufficiency rating while allowing the bridge manager to specify the replacement type and replacement objectives. Also, the use of the Markov transition matrix to predict future individual structure data and future bridge network characteristics and to forecast replacement policy decisions adds a valuable prioritizing tool to the bridge inspection system. Finally, a separate category of structures not qualified for NBIS, the LT20 system, is proposed and discussed. Future research avenues include the development of a stand-alone database network, the compilation of user manuals, and the presentation of the database in the form of a technology transfer program.

17. Key Words bridge inspection, bridge inventory, Markov chains, transition matrix, bridge management, database systems

18. Distribution Statement

19. Security Classif (of this report) Unclassified

20. Security Classif. (of this page) Unclassified

21. No of Pages 167

22. Price

Form DOT F 1700.7 (8-72)

iii

Contents

Contents .......................................................................................................................................................... iii List of Figures ........................................................................................................................................................... v List of Tables ......................................................................................................................................................... vii Executive Summary...................................................................................................................................................... viii 1.0 Introduction, Problem Statement, and Overall Project Approach............................................................................. 1

Introduction ................................................................................................................................................................ 1 Problem Statement...................................................................................................................................................... 2 Overall Project Approach ........................................................................................................................................... 2

2.0 Background ........................................................................................................................................................... 4

A Brief Survey of Bridge Management ...................................................................................................................... 4 The Rating of Condition States................................................................................................................................... 6 The Development of Cost Data and Cost Models ...................................................................................................... 7 The Management of Smaller Bridge Structures in Alabama ...................................................................................... 8

3.0 Development of the LT20 Inspection Process ........................................................................................................ 15

Inspection Process .................................................................................................................................................... 15 Data Collection and Inspection................................................................................................................................. 15 Sufficiency Rating Factors ....................................................................................................................................... 19 Hydrological Information ......................................................................................................................................... 20 Condition Ratings ..................................................................................................................................................... 21

Deck...................................................................................................................................................................... 21 Superstructure....................................................................................................................................................... 22 Substructure.......................................................................................................................................................... 22 Channel and Channel Protection .......................................................................................................................... 23

Photographic Requirements...................................................................................................................................... 24 Roadway Conditions............................................................................................................................................. 24 Structural Elements............................................................................................................................................... 25 Upstream and Downstream Cross Sections .......................................................................................................... 27

4.0 The BRPD LT20 Bridge Sufficiency Rating .......................................................................................................... 28

Bridge Replacement Prioritization Using the Sufficiency Rating ............................................................................ 28 The BRPD Sufficiency Rating.................................................................................................................................. 28

ADT...................................................................................................................................................................... 29 Roadway Classification ........................................................................................................................................ 30 Structural Adequacy ............................................................................................................................................. 32 Load Rating .......................................................................................................................................................... 33 Serviceability ........................................................................................................................................................ 34 Analysis of the Composite Sufficiency Rating..................................................................................................... 36

5.0 Replacement and Rehabilitation Case Studies........................................................................................................ 39

Replacement and Rehabilitation Case Studies.......................................................................................................... 39 Replacement Using Reinforced Concrete Pipe......................................................................................................... 40 Total Replacement Using Metal Pipe ....................................................................................................................... 44 Rehabilitation Using Slip Fit Lining Techniques ..................................................................................................... 46 Rehabilitation Using Glue Laminated Timber Deck Panels ..................................................................................... 49 Replacement Using Precast Concrete Span Sections................................................................................................ 51 Replacement Using Steel Beams with a Cast in Place Concrete Deck..................................................................... 53 Summary of Case Study Findings ............................................................................................................................ 54

iv

6.0 Bridge Replacement Prioritization Methods........................................................................................................... 55 Data Management..................................................................................................................................................... 55 The Classifying of Condition States ......................................................................................................................... 55 The Markov Chaining Function................................................................................................................................ 55 Application of the Markov Transition Matrix to Existing Condition Ratings .......................................................... 59 Prediction of Future Sufficiency Ratings.................................................................................................................. 60

7.0 Recommended Applications of the Local Roads BRPD ........................................................................................ 62

Recommendations for Use........................................................................................................................................ 62 The BRPD Inspection and Filing System ............................................................................................................. 62 Effectiveness of Prioritization Algorithm............................................................................................................. 62 The Initial Markov Matrix .................................................................................................................................... 62 Appropriate Cost Models...................................................................................................................................... 63 Use of the Output.................................................................................................................................................. 63

Recommendations for Further Development of the Local Roads BRPD ................................................................. 63 8.0 References ......................................................................................................................................................... 64 Appendix A: The BRPD Focus Group Survey ...................................................................................................... 66 Appendix B: BRPD Focus Group Survey Results ................................................................................................ 72 Appendix C: BRPD Inspection Data Sheet ........................................................................................................... 83 Appendix D: Shelby County BRPD Group Study................................................................................................. 86 Appendix E: BRPD Bridge Replacement Cost Figures ...................................................................................... 105 Appendix F: BRPD Bridge Replacement Feasibility Tables .............................................................................. 117 Appendix G: BRPD Photographic Record .......................................................................................................... 134 Appendix H: NBIS Condition Ratings in Shelby County.................................................................................... 150 Appendix I: Initial Markov Probability Matrices............................................................................................... 155 Appendix J: Weighted Average Markov Probability Matrices .......................................................................... 160 Appendix K: Projected 20-year Condition Rating Matrices ................................................................................ 163

v

List of Figures page Figure 2-1 ALDOT Memorandum 94-07.................................................................................................................9 Figure 2-2 Field Tally Sheet for LT20 Inspections ................................................................................................10 Figure 2-3 Typical Memorandum 94-07 LT20 Response Worksheet....................................................................11 Figure 3-1 Summary of Sufficiency Rating Factors...............................................................................................19 Figure 3-2 Roadway Surface..................................................................................................................................25 Figure 3-3 Deteriorated Abutment .........................................................................................................................26 Figure 3-4 Deteriorated Outside Stringer and Deck Planks ...................................................................................26 Figure 3-5 Downstream Cross Section...................................................................................................................27 Figure 4-1 Example of a Sufficiency Rating Computation ....................................................................................37 Figure 5-1 Laying Reinforced Concrete Arch Pipe with a Trackhoe.....................................................................41 Figure 5-2 Cost of Circular and Arch Shaped Reinforced Concrete Pipe with Headwalls or Projecting

from Fill................................................................................................................................................42 Figure 5-3 Replacement Cost Using Concrete Pipe with Headwalls .....................................................................43 Figure 5-4 Replacement Cost Using Galvanized Metal Pipe with Headwalls or Projecting from Fill ..................45 Figure 5-5 Pulling Liner Inside Existing Pipe........................................................................................................48 Figure 5-6 Cost of Rehabilitation Using Liners vs. Replacement Using Concrete or Metal Pipe..........................49 Figure 5-7 Rehabilitation Using Timber Glue Laminated Panels ..........................................................................50 Figure 5-8 Typical Cast-in-Place Abutment for Precast Concrete Deck Sections .................................................52 Figure 5-9 Setting Precast Concrete Span Sections ...............................................................................................52 Figure 6-1 Identity Matrix Model for a 20% Replacement Policy.........................................................................58 Figure 6-2 Substructure Probability Matrix and 20-year Projection ......................................................................59 Figure 6-3 20-year Projection of Existing Condition Rating of 6 ..........................................................................60 Figure E-1 Replacement Cost Using Circular and Arch Shaped Reinforced Concrete Pipe with Headwalls

or Projecting from Fill ........................................................................................................................106 Figure E-2 Replacement Cost Using Circular and Arch Shaped Reinforced Concrete Pipe with Headwalls

or Projecting from Fill ........................................................................................................................106 Figure E-3 Replacement Cost Using Precast Concrete Box Culverts with Precast Headwalls or Projecting

from Fill..............................................................................................................................................107 Figure E-4 Replacement Cost Using Precast Concrete Box Culverts with Precast Headwalls or Projecting

from Fill..............................................................................................................................................107 Figure E-5 Replacement Cost of Using Concrete Piping with Headwalls............................................................108 Figure E-6 Replacement Cost of Using Concrete Piping Projecting from Fill .....................................................108 Figure E-7 Replacement Cost Using Galvanized Metal Pipe with Headwalls or Projecting from Fill ................109 Figure E-8 Replacement Cost Using Galvanized Metal Pipe with Headwalls or Projecting from Fill ................109 Figure E-9 Replacement Cost Using Asphalt Coated Metal Arch Pipe with Headwalls or Projecting from

Fill ......................................................................................................................................................110 Figure E-10 Replacement Cost Using Asphalt Coated Metal Arch Pipe with Headwalls or Projecting from

Fill ......................................................................................................................................................110 Figure E-11 Replacement Cost Circular Reinforced Concrete Pipe versus Plain Galvanized Metal Pipe with

Headwalls or Projecting from Fill ......................................................................................................111 Figure E-12 Replacement Cost Arched Shaped Reinforced Concrete Pipe versus Plain Galvanized Metal

Pipe with Headwalls or Projecting from Fill ......................................................................................111 Figure E-13 Replacement Cost Using Concrete Boxes and Arched Shaped Concrete and Metal Pipe with

Headwalls ...........................................................................................................................................112 Figure E-14 Rehabilitation Using Pipe Liners or Glue Laminated Panel Sections ................................................112 Figure E-15 Rehabilitation Using Pipe Liners or Glue Laminated Panel Sections ................................................113

vi

Figure E-16 Cost of Rehabilitation Using Liners vs. Replacement Using Concrete or Metal Pipe........................113 Figure E-17 Cost of Rehabilitation Using Liners vs. Replacement Using Concrete or Metal Pipe........................114 Figure E-18 Replacement Cost Using Precast Concrete Panel Sections or Steel Beams with a Cast in Place

Concrete Deck ....................................................................................................................................114 Figure E-19 Replacement Cost Using Precast Concrete Panel Sections or Steel Beams with a Cast in Place

Concrete Deck ....................................................................................................................................115 Figure E-20 Replacement Cost Using Precast Box Culverts vs. Concrete Panel Sections or Steel Beams

with a Cast in Place Concrete Deck....................................................................................................115 Figure E-21 Replacement Cost Using Precast Concrete Panel Sections or Steel Beams with a Cast in Place

Concrete Deck ....................................................................................................................................116 Figure G-22 Timber Bridge Failure ........................................................................................................................135 Figure G-23 Typical Deteriorated Timber LT-20 ...................................................................................................135 Figure G-24 Deteriorated Deck and Superstructure................................................................................................136 Figure G-25 Misalignment of Substructure ............................................................................................................136 Figure G-26 Severe Erosion....................................................................................................................................137 Figure G-27 Crushing of the Cap on a Short Span Timber LT-20 (~5 feet) ...........................................................137 Figure G-28 Rehabilitated LT-20 Using a Temporary Steel Pile Bent ...................................................................138 Figure G-29 LT-20 with Steel Beams and a Cast in Place Concrete Deck .............................................................138 Figure G-30 Typical Corrugated Metal LT-20 .......................................................................................................139 Figure G-31 Deteriorated Corrugated Metal Pipe...................................................................................................139 Figure G-32 Removal of a deteriorated LT-20 .......................................................................................................140 Figure G-33 Placement of Bedding Material ..........................................................................................................140 Figure G-34 Laying Reinforced Concrete Arch Pipes with a Trackhoe .................................................................141 Figure G-35 Reinforced Concrete Pipe with Cast in Place Concrete Headwall......................................................141 Figure G-36 Reinforced Concrete Arch Pipe Projecting from Fill with Riprap in Place........................................142 Figure G-37 Galvanized Metal Pipe Projecting from Fill .......................................................................................142 Figure G-38 Using a Crane to Lay Precast Reinforced Concrete Boxes.................................................................143 Figure G-39 Reinforced Concrete Box with Precast Wingwalls.............................................................................143 Figure G-40 Double Line of Concrete Boxes with Precast Wingwalls...................................................................144 Figure G-41 Double Line of Concrete Boxes Projecting from Fill.........................................................................144 Figure G-42 Pulling Liner Inside Existing Pipe......................................................................................................145 Figure G-43 Rehabilitation Using Liner Pipes........................................................................................................145 Figure G-44 Rehabilitation Using Timber Glue Laminated Panels ........................................................................146 Figure G-45 Concrete Bridge Abutment.................................................................................................................146 Figure G-46 Abutment for Precast Concrete Span Sections ...................................................................................147 Figure G-47 Setting Precast Concrete Span Sections .............................................................................................147 Figure G-48 Setting Precast Concrete Parapets ......................................................................................................148 Figure G-49 Precast Concrete Bridge Built of Span Sections.................................................................................148 Figure G-50 Steel Beams with a Cast in Place Concrete Deck...............................................................................149 Figure I-1 Deck Transition Matrix 1999 to 2001 ................................................................................................156 Figure I-2 Deck Transition Matrix 1997 to 1999 ................................................................................................156 Figure I-3 Superstructure Transition Matrix 1999 to 2001..................................................................................157 Figure I-4 Superstructure Transition Matrix 1997 to 1999..................................................................................157 Figure I-5 Substructure Transition Matrix 1999 to 2001.....................................................................................158 Figure I-6 Substructure Transition Matrix 1997 to 1999.....................................................................................158 Figure I-7 Channel Transition Matrix 1999 to 2001............................................................................................159 Figure I-8 Channel Transition Matrix 1997 to 1999............................................................................................159 Figure J-1 Weighted Deck and Superstructure Matrices .....................................................................................161 Figure J-2 Weighted Substructure and Channel Matrices....................................................................................162 Figure K-1 Projected 20-Year Deck Condition Rating Matrix .............................................................................164 Figure K-2 Projected 20-Year Superstructure Rating Matrix ...............................................................................165 Figure K-3 Projected 20-Year Substructure Condition Rating Matrix..................................................................166 Figure K-4 Projected 20-Year Channel Condition Rating Matrix ........................................................................167

vii

List of Tables

number page Table 2-1 Example Data from Shelby County LT20 Replacement Priority Report .............................................12 Table 3-1 Item Numbers Represented in the NBIS Sufficiency Rating................................................................20 Table 3-2 Deck Condition Rating Codes ..............................................................................................................21 Table 3-3 Superstructure Condition Rating Codes ...............................................................................................22 Table 3-4 Substructure Condition Rating Codes ..................................................................................................23 Table 3-5 Channel and Channel Protection Condition Rating Codes ...................................................................24 Table 4-1 Factors Contributing to Sufficiency Rating..........................................................................................29 Table 4-2 Coding for Various ADT Ranges .........................................................................................................30 Table 4-3 Average Daily Traffic Counts and ADT Codes for the Shelby County Group Study ..........................30 Table 4-4 Roadway Classifications ......................................................................................................................31 Table 4-5 Roadway Classifications and RC Codes for the Shelby County Group Study .....................................32 Table 4-6 Condition Ratings and SA Codes for the Shelby County Group Study................................................33 Table 4-7 Coding for Posting by Percent of Legal Load ......................................................................................34 Table 4-8 Bridge Inventory Ratings and LR Codes for the Shelby County Group Study ....................................34 Table 4-9 Coding for Posting by Percent of Roadway Width and ADT...............................................................35 Table 4-10 Coding for Effectiveness of Existing Safety Features ..........................................................................35 Table 4-11 Percent Bridge Width, Safety Grades, and BW+SF Codes for the Shelby County Group Study.........36 Table 4-12 Required Bridge Information................................................................................................................37 Table 4-13 Component Code Computations...........................................................................................................37 Table 4-14 Sufficiency Codes and Composite Sufficiency Ratings for the Shelby County Group Study..............38 Table 5-1 Summary of Replacement Cost Using Concrete Pipe ..........................................................................41 Table 5-2 Summary of Replacement Cost Using Metal Piping ............................................................................44 Table 5-3 Summary Cost of Rehabilitation Using Liner Pipe ..............................................................................48 Table 5-4 Cost Summary of Rehabilitation Using Glue Laminated Timber Panels .............................................50 Table 5-5 Summary of Replacement Cost Using Precast Concrete Span Sections ..............................................51 Table 5-6 Summary of Replacement Cost Using Steel Beams with a CIP Concrete Deck ..................................53 Table 5-7 Summary Costs of Preferred Replacement Alternatives ......................................................................54 Table 6-1 Projected ADT’s, Condition Ratings, and Sufficiency Ratings for the Shelby County Group

Study.....................................................................................................................................................61 Table F-1 Replacement Using Reinforced Concrete Pipe with Headwalls.........................................................118 Table F-2 Replacement Using Reinforced Concrete Pipe Projecting From Fill ................................................119 Table F-3 Replacement Using Reinforced Concrete Arch Pipe with Headwalls ................................................120 Table F-4 Replacement Using Reinforced Concrete Arch Pipe Projecting From Fill ........................................121 Table F-5 Replacement Using Reinforced Concrete Box Culverts with Headwalls...........................................122 Table F-6 Replacement Using Reinforced Concrete Box Culverts Projecting from Fill ....................................123 Table F-7 Replacement Using Plain Galvanized Pipe with Headwalls...............................................................124 Table F-8 Replacement Using Plain Galvanized Pipe Projecting from Fill ........................................................125 Table F-9 Replacement Using Plain Galvanized Arch Pipe with Headwalls......................................................126 Table F-10 Replacement Using Plain Galvanized Arch Pipe Projecting from Fill ...............................................127 Table F-11 Replacement Using Asphalt Coated Metal Arch Pipe with Paved Invert with Headwalls.................128 Table F-12 Replacement Using Asphalt Coated Metal Arch Pipe with Paved Invert Projecting from Fill ..........129 Table F-13 Rehabilitation Using Liner Pipes........................................................................................................130 Table F-14 Rehabilitation Using Glue Laminated Timber Panels ........................................................................131 Table F-15 Replacement Using Precast Concrete Span Sections with Concrete Abutments................................132 Table F-16 Replacement Using Steel Beam Superstructure with a Cast in Place Concrete Deck ........................133

viii

Executive Summary Bridge inspection and replacement prioritization are vital tools used to compete for the finite pools of federal, state, and local government funds. Without these funds, an agency’s ability to manage, repair, rehabilitate, and replace aging bridge infrastructure is greatly hampered. To date, the development of inspection and replacement prioritization research, tools, and technology has been concentrated on the larger problem of the National Bridge Inventory System (NBIS). As a result, the growing problem of deteriorating structures that are not directly eligible for Federal Aid Bridge Replacement funds or state bridge funds has been greatly ignored. However, there is a growing need for investigation and application of bridge database inventory, bridge system networking, and bridge replacement prioritization systems for bridges that do not qualify as NBIS structures. Useful bridge inspection tools, techniques, and prioritization processes are given herein that are similar to those used in the existing Alabama Bridge Inventory Management System and other NBIS inspection and prioritization systems. Simplified reporting and streamlined prioritizing encourage the voluntary incorporation of this system into a local government’s existing bridge inspection and replacement program.

The inspection and prioritization procedures herein follow general NBIS recommendations for defining a bridge’s sufficiency rating while allowing the bridge manager to specify the replacement type and replacement objectives. Also, the use of the Markov transition matrix to predict future individual structure data and future bridge network characteristics and to forecast replacement policy decisions adds a valuable prioritizing tool to the bridge inspection system. Finally, a separate category of structures not qualified for NBIS, the LT20 system, is proposed and discussed. Future research avenues include the development of a stand-alone database network, the compilation of user manuals, and the presentation of the database in the form of a technology transfer program.

1

Section 1 Introduction, Problem Statement, and Overall Project Approach

Introduction

In the local government budgeting process, the prioritization of funding is an extremely important task. Critical choices in funding can be made with little or no grasp of the immediate or long-term effects if the proper planning tools are not in place. As an example, a recent survey of 44 participating counties by the Alabama County Engineer’s Association (ACEA) notes that total funding of $116,875,235 is needed to replace bridges within the local road system which are "less than 20 feet in length" (LT20) and are structurally deficient (“The Crisis Continues”, ACEA Legislative Report, 1999). Significantly, experience shows that these structures can generally be replaced for less than $50,000 per structure. However, these structures are usually considered minor structures and are thus not generally catalogued and prioritized for replacement.

The obvious explanation is that this funding deficit has arisen from a lack of advance planning, a lack of technical planning tools, and a lack of emphasis on the importance of prioritizing all segments of the county road infrastructure. In fact, counties have very limited resources to earmark for evaluating their infrastructure management programs. Complex analytical tools are available for use on structures that qualify as National Bridge Inventory System (NBIS) bridge-length. However, these tools are not always easy to use or applicable to smaller structures. In particular, the ABIMS (Alabama Bridge Inspection & Management System) now being utilized through the Alabama Department of Transportation (ALDOT) is exemplary of the NBIS inspection and bridge management system guidelines. Unfortunately, the system is quite burdensome to apply to LT20 structures. By altering the coding on a single element, a user can elect to input minor structures but all 450+ items, including scour and maintenance data, must then be input for the prioritization subroutine to be effective and accurate. Although achievable, the monumental task of entering minor structures into ABIMS has not been attempted to the knowledge of the investigators. It stands to reason that there is a quantifiable, yet ill-defined, need for development and distribution of simplified tools and an adaptable database engine to assist counties and municipalities in prioritizing bridge structures for replacement.

Shelby County, Alabama, provided data supporting their continuing efforts to prioritize their LT20 bridge replacement needs. Shelby County has developed a query-able database that received great interest when presented to the ACEA Annual Convention in Gulf Shores in 1999. Furthermore, Shelby County’s efforts focusing on the county LT20 system received praise from ALDOT County Transportation Engineer. Finally, interest was expressed by local government agencies throughout Alabama and the Southeast Region through positive response to a written survey. Therefore, a demonstrable need for a generalized database model exists.

2

Problem Statement

The purpose of the Local Roads Bridge Replacement Prioritization Database (BRPD) project is to research, specify, construct, distribute and provide training in the use of an LT20 bridge replacement prioritization database to be utilized on the County or municipal governmental level by professional practitioners of engineering. The resulting database and application tools are meant to supplement the bridge replacement prioritization process by providing a simplified means to prioritize all structures with an overall span length of less than 20 feet and a cross-sectional opening greater than 40 square feet. The reader is encouraged to note that this database is to be used in tandem with, not as a substitute for or modification to, databases that are already in use. Furthermore, the database structure developed by this research is intended to be stand-alone and maintained by local government bridge inspection personnel. It is not currently within the scope of the project to collect network specific information for all counties or other political subdivisions within the state.

Final database development, beta testing, troubleshooting, and preparation of instructional literature are outside the scope of this research and are currently under consideration for a second phase of continued research.

Overall Project Approach

In 1999, Shelby County’s groundbreaking LT20 replacement prioritization program was presented to Alabama county engineers at the annual Association of County Engineers of Alabama Conference. This presentation generated professional and academic interest in the BRPD database tool and initiated funding for research and development.

Initially, a thorough review of bridge management literature was conducted. In particular, a comprehensive listing of accepted prioritization tools and algorithms, related research, and practicing peers was compiled. It was immediately apparent that there was a dearth of information on bridge management, and an almost absolute void of academic study on bridge structures less than 20 feet in length.

Research began with the development of recommendations for collecting and prioritizing replacement data. Additionally, existing bridge inspection tools and techniques were reviewed to generate a parallel protocol for inspection of bridges less than 20 feet in length. It was determined that the inspection of LT20 bridges could be formulated as an abbreviated version of the NBIS Routine and Interim Inspection protocol. By assuming a simplified parallel inspection protocol, the research team felt that assimilation into existing bridge inspection programs would be beneficial and more generally accepted by practitioners.

Several algorithms that were designed to quantify a bridge’s structural adequacy or deficiency were explored. Two such algorithms showed much promise—a probabilistic approach based on Markov transition matrices and a linear approach based on the existing NBIS sufficiency rating. Both algorithms are reported herein. While the second approach is easier to apply, the lack, in most cases, of a data correction for future conditions helps justify the application of the first approach. The underlying problem in applying the first method lies in identifying the initial

3

transition probability matrix. After several cycles of data are entered, the predicted replacement priorities between these two methods correspond. Of note is the ability of the Markov prediction to effectively “learn” the characteristic patterns of decay in any given system over time. Therefore, it is especially adaptable to the LT20 bridge network since few counties systematically inspected these structures prior to this research.

A focus group survey was developed and distributed to 15 counties and three municipalities. Results were compiled from the responses. Most of the responders noted that they would be interested in making use of an inspection and prioritization system on a voluntary basis.

A peer group meeting was scheduled between University of Alabama (UA) professors Dr. Jim Richardson and Dr. Michael Triche and the University of Alabama at Birmingham (UAB) research team. Data and findings on similar ongoing research efforts were discussed. Further review of the linear function of deficiency currently utilized by ALDOT was conducted. Thus, the input of the peer group and additional research into the ALDOT deficiency rating led the research team to include a linear sufficiency rating similar to the traditional NBIS sufficiency rating. Then, the Markov transition matrix was applied to predict future sufficiency ratings and to project the effects of various bridge replacement alternatives. Again, the problem appeared to be the absolute lack of research on structures less than 20 feet in length. The UA group also shared with the research team the historical context of the definition of a bridge by the NBIS.

A final draft report was prepared for the University Transportation Center of Alabama (UTCA) for review, approval, publication, and posting of the UTCA web page.

Suggested future research includes choosing a format to present the database to local government agencies for use, beta testing the database engine using various LT20 networks, conducting a seminar to disseminate the database engine, and presenting of the findings herein on a regional or national scale. A discussion of the direction of these future activities is included in the conclusion of this report.

4

Section 2 Background

A Brief Survey of Bridge Management

Since the 1970’s, bridge inspection techniques have evolved widely due to the concerns associated with the overwhelming need to inventory the condition of the growing number of structurally deficient bridges.

In the 1980’s, independent concerns with the proper inspection and safety of culverts was addressed as a result of several tragic failures. In 1986, the Federal Highway Administration (FHWA) Culvert Inspection Manual was produced as a result of research that proved the significance of addressing the inspection and management of these structures. Although the Culvert Inspection Manual filled an enormous void for significant highway structures that were being overlooked, there are remaining bridge structures less than 20 feet in span that are not specifically addressed in most county and municipal inspection and maintenance programs.

It has been established that the most distinguishing factors that separate bridges and culverts are hydraulics, structural behavior, maintenance requirements, and the inspection techniques used on each. The National Bridge Inspection Standard currently defines the structures that are the focus of this research as culverts due to their length parallel to the roadway being less than 20 feet, hence the name LT20. LT20’s are defined as any structure supporting traffic that is less than 20 feet in span and having a cross sectional area of 40 square feet or greater. Some of the structures defined as LT20’s hydraulically behave like culverts and are constructed of piping material that is typical for culverts. Other LT20 structures behave as bridges both hydraulically and structurally. Nevertheless local governments maintain the majority of LT20’s with only emergency response or happenstance inspection and maintenance activities. All of these structures pose a significant threat to the safety of traffic in the event of their failure or an economic impact in the event of closure.

Bridges on rural roads tend to be older and to have a higher percentage of structural problems than bridges in urban areas. The maintenance responsibility for these rural bridges falls primarily on state and local governments. Nationwide, local governments have maintenance responsibility for over 50% of these rural bridges, while state governments maintain 42%. In most states, local governments have maintenance responsibilities for over 80% of the deficient or obsolete bridges on the state network.

Unfortunately, local governments usually have more bridge problems than available funds. The increasing age of LT20’s and reduced maintenance budgets have resulted in crisis-level funding for these structures, demanding precedence over routine maintenance.

5

LT20 structures are crucial in retaining rural access for emergency vehicles (fire trucks and ambulances), service vehicles (telephone and electricity), and school buses. Rural economies depend on the availability of reliable truck transportation to develop more diversified economies. However, economic development is nearly impossible with restricted routes due to load posted bridges.

The objective of adopting a prioritization database program is to improve the overall condition of an agency’s network of LT20’s that are often overlooked until failure occurs. An inspection process and database system tailored to meet the needs of LT20’s will aid in the successful prediction of structures that are severely in need of replacement before lapsing into an unsafe state. Changing service conditions may affect once competent structures so that they no longer meet load or traffic requirements. The need for a prioritization database system is significant in determining the condition rating of a structure within a network and determining a replacement schedule in order to utilize the available funds in the most effective and efficient manner possible.

The Surface Transportation Assistance Act of 1978 changed the basis for eligibility of bridges for federal funding. Under this act, the National Bridge Inspection Program (NBIP) was expanded to include bridges on all public roads, not just principle highways. The Bridge Management System (BMS) was later created to establish the most cost effective maintenance schedule for a network of bridges. The database connected to the bridge management system stores data from periodic field inspections. The information stored in the database can be used as input to create deterioration models. These models are used to predict future conditions for each element of the structure and to perform a “what if” analysis under different budget constraints to determine the impacts of carrying out different projects. The three primary types of models used are deterioration, cost and optimization models. All of these models were reviewed and taken into consideration in the development of the local roads BRPD.

In fact, sections of the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991, Transportation Equity Act for the 21st Century (TEA21), and other recent highway funding bills all require use of bridge management systems and maintenance of bridge inspection database records. Furthermore, the upkeep of these records has proven to greatly reduce liability in failure cases. Despite these findings, most Alabama counties do not currently maintain a formal list and inspection files for LT20’s.

Several types of data can be provided from effective bridge management systems. This data may include historical conditions, historical funding levels, anticipated deterioration rates, costs of various maintenance activities, costs of various replacement activities, present condition of the system and of individual bridges, overall costs of specific projects, ranking of proposed projects, listing of maintenance needs, and projected budget needs for system-wide or specific maintenance activities.

Cost data from a bridge management system can be subdivided by level or type. For example, costs may be associated with the entire network of bridges or may be associated with a specific project. Also, costs may be classified as agency or user costs. Components of each of these levels or types of costs may be selected to reduce bridge replacement estimates to the maximum level of detail desired or required. Some desirable attributes of cost models include, but are not

6

limited to, currency of data, consistency of data, reasonable updating frequency of data, and sensitivity to policy decisions or changes.

A bridge management system provides data that can be used for several purposes. First, the data provides information to transportation agencies that can assist in developing cost-effective bridge maintenance and replacement programs. Second, the data can be used as defensible support for specific funding requests. Finally, the data can provide a detailed picture of the effectiveness of ongoing bridge maintenance activities (Transportation Research Board, Research Record No. 1184, 1988).

A management planner has several needs to accurately forecast or prioritize a bridge replacement program. These include proposed funding levels at a given time, how that level of funding affects future funding needs of the system, charts and graphs that illustrate proposed funding, a definition of optimal funding, and resulting bridge needs based on funding type. All of these outputs are valuable tools for accurately depicting bridge management system results (Kivisto & Fleming. Transportation Research Board & National Research Council, 1995).

It is necessary to consider the level of service that bridge networks or individual structures are expected or desired to meet. Limits of acceptable to intermediate to desirable levels of service may be projected using data from the bridge management system. This level of service can be defined by load capacity, clear bridge deck width, vertical roadway under clearances or over clearances, and other structural and geometric factors. Also, level of service goals can be dependent on independently functioning variables such as average daily traffic (ADT) or average daily truck traffic (ADTT). Functional classification, a variable that is dependent on ADT and other factors, can be used to further classify the level of service model. This classification system may be applied to segments between intersections, corridors between major and minor points, countywide systems of travel, and local roads. The functional classification of a network allows for assigning integer values to each level of function of a roadway, and can be used to further categorize a bridge or bridge network’s level of service.

The Rating of Condition States

In a bridge management system, it is necessary to quantify certain variables that are in effect appraisals of a structure’s or structural element’s condition, or condition state. Condition states can be either continuous or discrete. A continuous condition state addresses singular activities at each stage of the bridge network’s lifecycle (i.e., preventative, corrective, routine, repair, rehabilitation, or replacement). The associated cost functions capture the benefit of prevention of early decay and correction of a deficiency. Thus, the cost functions capture the effects of deferring capital investments into the system.

If a system can be defined that allows for condition state analysis that is continuous rather than discrete, then several characteristics of the bridge network can be established. First, the system may address the effects of singular activities at each stage of the evolution of the condition state model. For instance, the system may seek out the effects of preventative, corrective, routine, repair, rehabilitation, and replacement activities on the evolution of the bridge network’s condition states, or the system may seek to more accurately model the effects of alternatives of

7

each activity. Second, cost functions inherent to each activity can be used to capture the benefit of prevention of early decay, the correction of deficiency, or the adverse cost of increased or changing user patterns. Thus the cost and benefit of concentrating particular maintenance or replacement activities on a region of the bridge network or on the entire network can be weighed.

Third, penalties for do-nothing activities or deferred investing of resources can be accurately assessed. Thus, the long-range benefit of investing limited revenue into the bridge network versus, for instance, the cost of not investing in lieu of other needed or desired activities can be projected.

A discrete condition state describes the distribution of conditions among a population of bridges or bridge elements in terms of condition states. Transitions between these states are reflected as negative (deterioration) or positive (maintenance, repair and rehabilitation). The aim of a bridge management policy is to effectively improve the condition of an acceptable percentage of the total population from one condition state to another. If unit costs for the element or bridge considered are correct, then additional cost penalties for performing work prior to need or after need can be assigned. The Markov transition matrix, discussed later, relies on the discretization of condition states within a system.

A “condition rating” or “urgency of need” indicator is typically used to rate various structural elements and to set replacement rank within a bridge management system. Most management systems currently in use are based on discrete condition ratings. Therefore, the methods of application in this report apply the accepted practice of discrete condition ratings to the problem of bridge network modeling.

The Development of Cost Data and Cost Models

Bridge management systems rely on cost models to predict, track, and report costs of policy initiatives and projects, and to predict the cost savings to transportation agencies and to road users of preventative maintenance and functional improvements. The absence of accurate cost models can greatly diminish the effectiveness of bridge management systems in analyzing the key tradeoffs in policy and program implementation. Costs that the bridge management system considers include user costs and benefits if attempts are made to make system-wide prioritization decisions. These costs have not generally been proven beneficial to cost estimates for specific projects (Kaminsky, 1986).

However, few agencies have focused in-depth attention on bridge cost or economic data. As a result, bridge policy suffers from a tendency to develop “scope creep” (National Cooperative Highway Research Program (NCHRP), Synthesis Report 227, 1996), or increasing costs as a project or program works through the planning process. This tendency to increase costs results in high contingency allowances, distrust of estimate findings by elected officials or upper level management, and lack of confidence in negotiating cost estimates with contractors.

The level of detail of the cost data used in a discrete state analysis requires the derivation of a single aggregate unit cost applicable to a population of bridges with similar characteristics. This aggregate cost can be composed of several sources, or data levels, within a bridge system. These

8

levels include network level data, project level data, and direct or indirect costs to users. Of the three levels of data, the user cost data may be the least understood, and therefore least utilized, of the data types. As recently as 1996, North Carolina was the only state using self-generated user costs to improve its policy decisions and project schedules.

User costs are defined as those costs resulting from factors such as traffic movement, deck ride quality, detour length, and work zones as they affect vehicle travel time and motorist safety. In several instances, the quantification of these user costs has been systematically derived. Thus, there is a trend in the literature to generally define and quantify the effects of user cost on the modeling of a bridge management and prioritization system.

The total unit data cost, in the form of network-level data or project-level data, is subject to the effects of at least two mechanisms. First, the composition of the bridge inventory data must be consistently determined and uniformly applied to the cost model. Second, known or suspected mechanisms of deterioration must support the type and detail of the deterioration model used. Otherwise, cost and deterioration may be affected to the extent that predictions are not within statistically meaningful margins of error. Thus, a bridge management system must attempt to quantify and eliminate errors that are fundamental to the applied prioritization model.

Therefore, a bridge management system must carefully consider possible failure modes for a specific population of bridges, must determine how to quantitatively identify and judge the progression of these failure modes in a population, and must determine how to accurately collect and maintain data on a population of bridges.

The Management of Smaller Bridge Structures in Alabama

The first recorded concern over the accelerating deterioration of the statewide LT20 bridge network can be traced to Alabama Department of Transportation Memorandum 94-07, dated January 21, 1994, and shown in its entirety in Figure 2-1.

This memorandum noted Governor Jim Folsom Jr.’s appointment of a task force to study the feasibility of a program similar to his father’s mid-century Farm to Market Economic Development program. The task force requested that each county submit a list of structurally deficient “…bridge type structures that are less than 20 feet in length…with 40 sq. ft. of opening or more…” on paved and unpaved county roads. The submitted information was forwarded to the ALDOT County Transportation Engineer’s office for compilation and delivery to the appointed task force.

9

Figure 2-1. ALDOT Memorandum 94-07

Figure 2-2 shows a typical field inspection worksheet that was used in Shelby County to collect the data required by ALDOT Memorandum 94-07. This data was generally collected over a period of two weeks, compiled, typed, and forwarded to the ALDOT County Transportation Engineer. The shaded entry notes that a previously non-documented NBIS bridge was found during the LT20 inspection process; therefore, this inspection process additionally benefited counties by identifying a previously non-inspected NBIS bridge subset that was being skipped by bridge inspectors.

10

Figure 2-2. Field Tally Sheet for LT20 Inspections

Figure 2-3 on the following page illustrates the typical response that the County Transportation Engineer’s office received from the participating counties. This data was then compiled by the County Transportation Bureau and forwarded through the Highway Director to the Governor’s office.

However, only 44 of 67 Alabama counties participated in the feasibility study. From the 44 participant counties, a projected statewide LT20 replacement cost of $116,875,234.80 was extrapolated. Projected deficiencies at that time were estimated to total 2,322 deficient structures statewide. Thus, the average LT20 replacement cost in 1994 was estimated to be $50,333.87 per structure.

In 1997, the Shelby County Highway Department embarked on an ambitious NBIS and LT20 bridge replacement prioritization program. The 1994 inventory of LT20’s indicated that Shelby County maintained 94 LT20 structures of which 80 were considered structurally deficient.

11

Therefore, the initial goal of the replacement program was an average of 12 deficient LT20’s a year, or one LT20 a month. This pace would have guaranteed the elimination of structurally deficient LT20’s by the end of 2005.

Figure 2-3. Typical Memorandum 94-07 LT20 Response Worksheet

12

As a function of BRPD research efforts, Shelby County bridge inspectors completed a second LT20 inspection cycle in 2001. This cycle was used to verify the initial deterioration data provided to ALDOT in 1994 and collect additional deterioration data past the 1997 initial full inspection cycle. An overall condition rating range from 0 (imminent failure requiring immediate closure) to 9 (new structure) was established. At that time, the bridge inspector was given the discretion in assessing marginal rating values based on NBIS inspection guidelines. This assumption was found to be satisfactory since the NBIS guidelines are set to critically judge global decay based on individual member characteristics. Therefore, accepted NBIS inspection techniques were successfully employed to refine the initial LT20 sufficiency measurements.

The initial and second rounds of inspection data were manually tabulated to show county road number, a description of the location, structure type, posting, and sufficiency rating. Again, a global sufficiency ranging from 0 to 9 was assigned. At first, the handwritten data was compiled and typed. However, it was soon evident that the use of available spreadsheet programs would greatly enhance efforts to manage the LT20 network of bridges. Table 2-1 illustrates how the Shelby County LT20 Prioritization Database began to evolve. For continuity, the subset of LT20 bridges shown below will be used as the example database throughout this report.

Table 2-1. Example Data from Shelby County LT20 Replacement Priority Report

Road Description Structure Number Culvert ADT Posting Suff.

Rating Raw Score

CR 86 1 mile East CR 306 086-59-575Q Timber 650 3 2 0.0000312475

Dirt Road Off Justice Rd Miller's Dairy to Calcis 000-59-515Q Timber 300 8 1 0.0000338951

CR 334 Off CR 11 (Acton Lane) 334-59-595Q Timber 100 7 3 0.0000349859CR 57 At Bearden Dairy 057-59-558Q Timber 200 3 1 0.0000512711

CR 450 U.S. 280 End 450-59-603Q Timber 100 3 1 0.0001051709CR 71 At CR 46/Spring Creek Grocery 071-59-566Q Timber 400 3 4 0.0001051709

CR 71 South of CR 405/New Shelby Peninsula 071-59-567Q Timber 400 4 5 0.0001331485

CR 77 At Farr Dairy 077-59-569Q Timber 100 3 2 0.0002214028CR 13 0.25 Mi. North of Slab Road 013-59-529Q Timber 1200 12 3 0.0002531512CR 42 East of AL 145 042-59-545Q Timber 300 12 2 0.0006893911CR 42 West of South River Road 042-59-546Q Timber 300 12 2 0.0006893911CR 46 West of AL 145 (at school) 046-59-548Q Timber 600 12 4 0.0006893911CR 46 At CR 47 046-59-549Q Timber 600 12 4 0.0006893911CR 26 At I-65 (Fulton Springs) 026-59-543Q Timber 3200 36 3 0.0009419083CR 26 At CR 17 026-59-542Q Timber 3100 36 3 0.0009724397CR 68 At Lake Terrace Subdivision 068-59-565Q Timber 3100 36 3 0.0009724397

CR 103 At Homestead Entrance 103-59-585Q Timber 3000 36 4 0.0013422619CR 446 George Foster 446-59-601Q Timber 200 12 3 0.0016183424CR 103 At Smith's Camp 103-59-584Q Timber 3000 12 6 0.0020201340CR 12 West of CR 87/Cattle Crossing 012-59-527Q Timber 1400 36 3 0.0021659812

13

At the request of the Shelby County Commission, a comprehensive catalog of all future infrastructure enhancements was compiled. The LT20 database was modified to include cost data and to establish a replacement priority protocol. The initial estimate yielded a total program cost of $2.2 million over a period of 15 years. A prioritized replacement list of 87 structures was established, and a rudimentary adjustment for inflation was added to the total program cost. In conclusion, it was determined that this program required an annual funding of approximately $150,000 a year over a 15-year period.

A review of Shelby County LT20 replacements to date indicated that all but one posted LT20 has been replaced. In addition, several NBIS structures have been “sized down” to LT20 status by replacement with structures less than 20 feet in total span length. Therefore, the prioritization policies of Shelby County seem to have a positive impact on the county’s ability to identify and execute a successful bridge replacement program. Shelby County’s bridge management team is currently implementing the techniques established in the LT20 prioritization program to NBIS bridges for replacement prioritization by Federal Bridge Replacement Funds, Amendment 1 Grant Anticipation Revenue Vehicle (GARVEE) Bond Funds, and County Special Project Funds.

One negative effect, or byproduct, of the Shelby County prioritization protocol was noted. There was a tendency for the data to act as a “still photograph” of past conditions. For example, it is evident that the data illustrated in Table 2-1 does not display the effects of the bridge replacement program. If one wished to add that data, then new columns could be added to the database. However, this increase in data begins to make the database cumbersome to maintain, and the procedure to extract a query becomes unnecessarily complicated. Thus, in the case of the prioritization data, no correction due to changed conditions was noted as structures were replaced. Obviously, one can choose to change the database to reflect changed conditions. However, once a change is recorded into this database, there is no mechanism to measure the continuing process of decay. Therefore, the need for a deterioration algorithm is evident. In fact, if the deterioration of the system can be established, a prediction of the system’s deterioration rate can be extrapolated. In conclusion, the prioritization of bridge replacements and the prediction of future funding requirements can be further refined by accurately predicting the rate of decay of the studied bridge network.

In a recent publication, “The Crisis Continues”, the bridges of local roads were addressed and the importance of their structural sufficiency was emphasized. Sufficiency, among many other contributing factors involving public safety, was the incentive for the development of a prioritization database for these structures that are often ignored until a failure or collapse occurs in some cases. Maintaining these structures is a major challenge for public works managers, engineers and maintenance personnel. Today, perhaps more than ever, keeping our infrastructure safe and functional with limited available financial resources requires innovative methods of prioritizing and replacing structures within a network.

Bridge system managers need tools that allow both a snapshot of the current conditions and an accurate predictor of future areas of deterioration. This predictor takes a system-wide format, allows for accurate study of individual structures, and is easy to learn, operate, and maintain. At the same time, care should be taken to insure that the deterioration predictor adjusts to account for the influence of certain loading and load cycling activities such as logging, farming, mining, and

14

commercial and residential development. The advent of the personal computer has made the application and maintenance of such a tool useful and producible. Therefore, there is a demonstrable need for the development of a simple, adaptable database tool for the prioritization of all county bridges.

15

Section 3 Development of the LT20 Inspection Process

Inspection Process

The inspection procedures for LT20’s depend on the type of structure and the materials used. Unlike most NBIS bridges it may not be possible to review construction plans of LT20’s in preparation for inspection, since plan sets do not exist on most LT20 structures. In many instances the locations of these structures may not be identified or recorded on any type of inventory or map. The first step before inspection is to successfully determine and record the location of each LT20 structure within the network. This may be done effectively by orienting the structure on a link and node system based on the route on which it serves or by using latitude and longitude coordinates determined by a Global Positioning System (GPS) system. The inspection of LT20 structures is similar to that of NBIS bridges or culverts. The inspection process was made as simple as possible by developing a one-page inspection form. This form contains all of the necessary information required for the prioritization database computations as well as useful engineering data that are required for the design of the replacement structure.

Data Collection and Inspection

Based on the response and input from participating counties, a simple, easy-to-use inspection report was developed. The LT20 Bridge Inspection Report is shown in its entirety on the next two pages. It was determined that in order to gain acceptance of an inspection process and prioritization database system for LT20’s the procedure must be as simplistic and straightforward as possible. An inspection report was developed to capture the following information:

• The structure’s identification information, location and current load rating. • Measurement of the approach road and roadway classification. • Design information such as hydrologic information and traffic volumes. • Geometry and type of existing structure. • Conditions ratings of the deck, superstructure, substructure and channel and channel

protection. • Inspector’s recommendations and comments. • Notes on photographs taken.

The items found on the inspection report were the focus in developing a prioritization database system. Typical LT20 bridges and culverts were broken into two overall inspection categories: (1) integrity of the structural material supporting traffic loads is coded in the structural condition ratings, (2) and the condition of the channel associated with the structure are coded in the channel and channel protection rating. A simplified inspection form was developed using the NBIS BI-5

16

and BI-6 inspection forms as guides. The LT20 Bridge Inspection Report is included on the following two pages of this report.

Ratings for LT20’s with typical bridge components were separated into four categories: deck, superstructure, substructure, and the channel and channel protection. The elements within each condition rating are rated using a 0 to 9-point scale in accordance with the guidelines developed in Section 3.4. The assignment of condition rating is subjective; therefore, the guidelines were needed as aids in assigning condition ratings for LT20’s in order to limit deviation that occurs during the inspection process.

As developed during this project, the inspection form simplistic, and it streamlines the data entry process that the inspector uses to move the field data into the database. Much of the data required on the inspection form may not be used in the prioritization process, although, after the replacement priority is assigned to the structure this excess data may play an important role in the selection of the replacement method on a case-by-case basis. The more detailed items such as the ADT, roadway measurements and hydraulic information on the inspection form aid in the identification of criteria that point to advantages in using the most sufficient and cost effective methods of replacement and materials.

17

Roadway Width Q25

Right Shoulder Width Q100

Total Width ADTRoadway Classification Projected ADT

Description of LT-20Material Length along Roadway CL

Skew Opening HeightLength along Streambed Opening Area

Condition RatingsDeck Rating Superstructure RatingWearing Surface Deck SlabDeck-Structural Stringers or Beams Railing PaintUtilities Rivets, Bolts or WeldsCollision Damage Collision Damage

Deflection Under LoadAlignment of MembersVibration Under Load

Overall Rating Overall Rating

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps Channel ScourWings Embankment ErosionBackwall DriftFooting / Drilled Shaft SiltPiles / Columns VegetationErosion / Scour Channel Migration Settlement Pier Protection Collision Damage Rip RapPiers or Bents Adequacy of Opening Caps Alignment with StructureColumnsFooting / Drilled ShaftPiles (PC,S,T)ScourSettlementBracingDebris on SeatsCollision Damage

Overall Rating Overall RatingLT-20 Bridge Inspection Report (Back)

cfscfs

deg.ftftft

ftftft

ft

18

LT-20 Bridge Inspection Report (Back)

Photograph Notes

Upstream Cross Section Remarks:

Photo ID -

Downstream Cross Section Remarks:

Photo ID -

Roadway Surface Remarks:

Photo ID -

Superstructure Remarks:

Photo ID -

Substructure Remarks:

Photo ID -

19

Sufficiency Rating Factors

Direct factors include but are not limited to average daily traffic (ADT), structural adequacy, serviceability, and load rating. Indirect factors include but are not limited to detour length, roadway classification, route importance, use by public transportation or emergency vehicles, and roadway condition.

An adequate prioritization model can be defined by establishing a group of three to five of the most important factors contributing to a need for rehabilitation or replacement within a bridge group. In the case of the LT20 system, five factors deserving consideration often include ADT, roadway classification, structural adequacy, serviceability and load rating or posting. These factors are used to develop the BRPD prioritization algorithm.

The importance of each rating factor was assigned as a percentage of the overall score. This importance varied as little as possible from the elements that characterize the NBIS sufficiency rating, since this rating is generally accepted by the bridge inspection community as a standard priority rating tool. The condition of a bridge can be classified under two different schemes. First, the condition of a bridge is rated according to one of three categories: non-deficient, structurally deficient, or functionally obsolete. Bridges that are classified as non-deficient are in satisfactory condition and adequately serve the specifications for which they were designed. Structurally deficient bridges are restricted to light traffic or closed because of structural inadequacy due to deteriorated structural components or an immediate need of rehabilitation in order to remain open. Functionally obsolete bridges are inadequate due to their geometry or the traffic on the roads they serve, although the bridges may be structurally sound. Second, a sufficiency rating is calculated based upon the National Bridge Inventory (NBI) data items related to its structural condition, functional obsolescence and essentiality for public use. Weighted percentages of these items are represented in Figure 3-1.

Summary of Sufficiency Rating Factors

Structural Adequacy and

Safety55%

Essentiality for Public Use

15%

Serviceability and Functional

Obsolescence30%

Figure 3-1. Summary of Sufficiency Rating Factors

20

The sufficiency rating is the sum of the NBIS item numbers shown below in Table 3-1 and is not less than 0.0 and not more than 100.0. Generally, the sufficiency rating of a bridge structure must be less than 50.0 for the structure to be eligible for replacement using Special Bridge Replacement Program (SBRP) funds.

Table 3-1. Item Numbers Represented in the NBIS Sufficiency Rating

NBIS Sufficiency Rating Factors Percent Contributing to the NBIS Sufficiency Rating

NBIS Item Numbers and Descriptions for Each Factor

Structural Adequacy and Safety 55%

#59 Superstructure #60 Substructure #61 Channel & Channel Protection #62 Culvert #66 Inventory Rating

Serviceability and Functional Obsolescence 30%

#58 Deck Condition #28 Lanes on the Structure #29 Average Daily Traffic #32 Approximate Roadway Width #43 Structure Type #51 Bridge Roadway Width #53 Vertical Clearance over Deck #67 Structural Evaluation #68 Deck Geometry #69 Under clearances #71 Waterway Adequacy #72 Appropriate Roadway Alignment #100 STRAHNET Highway Designation

Essentiality for Public Use 15%

#19 Detour Length #29 Average Daily Traffic #100 STRAHNET Highway Designation

Special Reduction Factors Not to Exceed 13% #19 Detour Length #36 Traffic Safety Features #43 Structure Type

Hydrological Information

The drainage area, in acres, contributing flow to the location of the structure in question can be measured on a topographic map or determined in the field. Typically, LT20 structures are designed on a 25-year return period or flood frequency. The design flow rates are calculated using various methods depending of the topography, surface condition, and size of the drainage area. For small (0-100 acre) uniform drainage areas the rational method is often used to calculate flow rates. The design flow rates for drainage areas that range from 100-280 acres, especially urban and urbanizing watersheds, are typically calculated using computer program methods such as TR-55 (Urban Hydrology for Small Watersheds, Technical Release 55). The United States Geological Survey has developed a nationwide series of water-supply papers titled the “Magnitude and Frequency of Floods in the United States.” The probable magnitudes of floods for various storm frequencies are represented by the regression equations developed and are generally used for determining the flow rate for drainage areas greater than 280 acres and up to 1027 square miles.

21

Condition Ratings

Deck

The condition of the roadway, pavement, and bridge deck affects traffic that the structure serves. The overall condition of the deck or roadway is to only consider the structural integrity of the deck and its ability to carry traffic load. Defects such as settlement or misalignment, potholes, poor drainage, and other conditions could lead to the impeding of traffic or the loss of vehicle control and therefore are noted. Splitting, crushing, fastener failure, and deterioration from rot effect load capacity and are identified and reflected in the rating when inspecting timber decks. Close attention is given to locations where the deck rests on other members of the superstructure or substructure. Excessive deflections and other movement in the deck caused by the application of dynamic live load are taken into account when rating the deck. Defects observed during inspection only affect the rating when they play a role in reducing the structural capacity of the structure. However, for maintenance purposes all structural problems, potential or existing, are detailed under miscellaneous comments on the LT20 inspection form.

General condition ratings that may be used as a guide in evaluating the deck are shown below.

Table 3-2. Deck Condition Rating Codes

Coding Description N Not applicable—in the case of the absence of any type of deck element.

9 Excellent Condition—usually pertains to a new structure.

8 Very Good Condition—structurally sound with no problem observed.

7 Good Condition—structurally sound with some minor problems such as small cracks or other minor defects.

6 Satisfactory Condition—minor deterioration caused by limited cracking, splitting, corrosion or limited fastener failure and wear.

5 Fair Condition—structurally sound with minor section loss, cracking, spalling, splitting, corrosion or fastener failure and wear.

4 Poor Condition—the structural integrity may be compromised due to advanced section loss, cracking, spalling, corrosion or fastener failure and wear.

3 Serious Condition—the structural integrity has been seriously affected by cracking, spalling, splitting, corrosion or fastener failure and wear.

2 Critical Condition—the structural integrity has been affected to the point for which it may be necessary to monitor the structure or temporarily close the structure until repairs are made.

1 Imminent Failure Condition—structure has been closed to traffic due to lack of structural capacity for all traffic until the completion of corrective actions that may put it back into light service.

0 Failed Condition—the structure has failed and is out of service until replacement is performed.

22

Superstructure

This item represents the structural condition of all the elements in the superstructure that contribute to the load-carrying capacity. This item is used to rate the barrel and other load-carrying components of an LT20 culvert. The cross section of the barrel in culvert structures is measured to adequately define the cross section in case of bulging or distortion that may affect the structural capacity of the structure. All superstructure elements are inspected for signs of distress, which include: cracking, deterioration, section loss, and malfunction or misalignment. Due to their potential to cause collapse of the entire structure, it is noted if fracture critical members are in distress. Table 3-3 below lists general condition ratings that can be used as a guide in evaluating the superstructure.

Table 3-3. Superstructure Condition Rating Codes

Coding Description

N Not Applicable—in the case of the absence of a superstructure such as a simple slab structure.

9 Excellent Condition—usually pertains to a new structure.

8 Very Good Condition—primary structural elements are sound with no problems observed.

7 Good Condition—minor problems such as small cracks or other defects.

6 Satisfactory Condition—minor deterioration such as cracking, splitting, corrosion.

5 Fair Condition—structurally sound with minor section loss, cracking, spalling, splitting, or limited local failure of connections.

4 Poor Condition—structural integrity may have been compromised due to advanced section loss, splitting, cracking, corrosion, spalling, or local failure of connections.

3 Serious Condition—loss of section, deterioration, spalling, seriously affected primary structural components. Local failures are possible. Fatigue cracks in steel or shear cracks in concrete.

2 Critical Condition—advanced deterioration of primary structural elements. Fatigue cracks in steel or shear cracks in concrete. Unless monitored closely, it may be necessary to close the structure until corrective action is taken.

1 Imminent Failure—major deterioration of section loss in critical structural components or obvious vertical or horizontal movement affecting structure stability. Structure is closed to traffic but corrective action may put it back in service.

0 Failed Condition—out of service, beyond corrective action.

Substructure

This item describes the structural ability of piers, abutments, piles, fenders, footings or other components to carry traffic and soil retention loads. Elements are inspected for cracking, section loss, settlement, misalignment, scour, collision damage, and corrosion. Footings are checked carefully for scour or undermining. A probing rod is used since scour holes can fill up with sediment. Defects of such magnitude that may cause collapse due to extensive loss of bearing or scour are reflected in the rating and notes are made detailing the extent and mode of potential failure due to such extensive deterioration. The following general condition ratings in Table 3-4 can be used as a guide in evaluating the substructure.

23

Table 3-4. Substructure Condition Rating Codes

Coding Description N Not Applicable.

9 Excellent Condition.

8 Very Good Condition—no problems observed.

7 Good Condition—minor problems such as small cracks or other defects.

6 Satisfactory Condition—elements are sound but may have minor deterioration.

5 Fair Condition—elements are sound but may have minor section loss, cracking, spalling or scour.

4 Poor Condition— advanced section loss, deterioration, spalling or scour.

3 Serious Condition— loss of section, deterioration, spalling or scour has seriously affected primary structural components. Local failures are possible. Fatigue cracks in steel or shear cracks in concrete.

2 Critical Condition— advanced deterioration of primary structural elements. Fatigue cracks in steel or shear cracks in concrete. Scour may have removed substructure support. Unless monitored closely it may be necessary to close the structure until corrective action is taken.

1 Imminent Failure— major deterioration of section loss in critical structural components or obvious vertical or horizontal movement affecting structure stability. Structure is closed to traffic but corrective action may put it back in service.

0 Failed Condition—out of service, beyond corrective action.

Channel and Channel Protection

The channel and channel protection represent the stream stability and the ability to allow the flow of water. The condition of stream stability, riprap or other slope protection is reflected in this rating. Excessive water velocity is potentially critical in effects such as undermining of slope protection or footings, erosion of banks, and realignment of the stream, which may result in immediate or potential problems. The general condition ratings in Table 3-5 on the following page can be used as a guide in evaluating the channel and channel protection associated with the structure.

24

Table 3-5. Channel and Channel Protection Condition Rating Codes

Coding Description

N Not applicable when the structure is not over water.

9 There are no noticeable or noteworthy deficiencies that affect the condition of the channel.

8 Banks are protected or well vegetated.

7 Bank protection is in need of minor repairs. Banks and/channel have minor amounts of drift.

6 Bank is beginning to slump. River control devices and embankment protection have widespread minor damage. There is a minor streambed movement evident. Debris is restricting waterway slightly.

5 Bank protection is being eroded. River control devices or embankment have major damage. Trees and brush restrict channel.

4 Bank and embankment protection is severely undermined. River control devices have severe damage. Large deposits of debris are in the waterway.

3 Bank protection has failed. River control devices have been destroyed. Streambed aggradations, degradation or lateral movement has changed the waterway to now threaten the structure and/or approach roadway.

2 The waterway has changed to the extent the structure is near a state of collapse.

1 Structure closed because of channel failure. Corrective action may put back in light service.

0 Structure closed because of channel failure. Replacement necessary.

Photographic Requirements

In the past there have been few guidelines for photographs taken during bridge inspection. With current advances in digital photographic capabilities, it is easier to capture and store images effectively. Quality digital images taken of each structure by the inspector at the time of inspection can be linked to the database system for easy reference. To ensure a complete photographic detailed database, summary guidelines were developed. All photographs will be stored in the database system in correlation with the structure’s identification number allowing office personnel to quickly access photographs of any LT20 when questions pertaining to a specific structure arise. These guidelines will ensure a complete and thorough reference to photographs of each structure for use in the database as quick reference for certain elements or conditions relative to the structure. Photographs play an important role as a reference to ensure the correct structure is identified during each inspection cycle.

Roadway Conditions

Pavement condition and serviceability condition of the existing roadway is represented in the photograph of the approach roadway. This photograph is taken 200 feet from the beginning of the LT20 (facing north or east) capturing an image of the roadway 200 feet before and beyond the structure. This photograph will represent the overall condition of the roadway. Issues such as pavement width, shoulder width, striping, and the condition of the wearing surface can be observed. An example photograph of the roadway condition is shown in Figure 3-2.

25

Figure 3-2. Roadway Surface

Structural Elements

The photographs of the structural elements will aid as a reference to each structure to ensure the correct structure is identified during each inspection cycle. Office personnel can also observe the extent and severity of the deterioration easily since they are stored in the database system in correlation with the structure’s identification number. These photographs represent the region of the structure in the most deteriorated condition. These photographs will include the superstructure and substructure or any other severely distressed structural member of the LT20. Figures 3-3 and 3-4 are examples of the required photos that represent the condition of the structural elements.

26

Figure 3-3. Deteriorated Abutment

Figure 3-4. Deteriorated Outside Stringer and Deck Planks

27

Upstream and Downstream Cross Sections

These photographs are used to identify existing scour and aggradations present during the inspection. They will also serve as an aid in hydraulic analysis and design. A rough determination of the general downstream cross section and an estimated amount of headroom available can be made in order to select the appropriate dimensions of the replacement material. These photographs are taken from the centerline of the roadway facing both downstream and upstream. An example photograph representing a typical downstream cross section is shown in Figure 3-5.

Figure 3-5. Downstream Cross Section

28

Section 4 The BRPD LT20 Bridge Sufficiency Rating

Bridge Replacement Prioritization Using the Sufficiency Rating

Probably the most useful element in the prioritization of structures for replacement is the structure's sufficiency rating. As discussed earlier, this rating is a composite measurement of individual elements contributing to an expression of the structure's overall deterioration. Since the individual components can be quantitative and qualitative in nature, the composite sufficiency rating gives the bridge manager an intrinsic, measurable, comparable factor for judging the replacement need of a given structure against a bridge network's other structures.

The BRPD Sufficiency Rating

As shown by the constructive elements of the sufficiency rating, several factors have a direct or an indirect influence over the prioritization of a bridge system. Direct factors include but are not limited to ADT, structural adequacy, serviceability, and load rating. Indirect factors include but are not limited to detour length, roadway classification, route importance, use by public transportation or emergency vehicles, and roadway condition.

An adequate prioritization model for LT20 bridges can be defined by establishing a group of three to five of the most important factors contributing to a need for rehabilitation or replacement within a bridge network. Five factors deserving consideration include ADT, roadway classification, structural adequacy, serviceability and load rating or posting. These factors are used to develop the BRPD composite sufficiency rating. The outcome of this algorithm can be presented in integer form, by rank of priority, or in decimal fraction form by sufficiency rating.

First, a percentage of importance of each factor is assigned. This percentage varies as little as possible from the elements that characterize the NBIS sufficiency rating, since this rating is generally accepted by the bridge inspection community as a bridge replacement priority rating guideline. For the BRPD sufficiency rating, the percentages in Table 4-1 on the following page make up the rating value.

29

Table 4-1. Factors Contributing to Sufficiency Rating

Factor Percentage of Sufficiency Rating

ADT 10%

Roadway Classification 5%

Structural Adequacy 30%

Load Rating, or Posting 25%

Serviceability 30%

It is noteworthy that ADT and Roadway Classification are essentiality for “use” factors, Structural Adequacy and Load Rating are “safety” factors, and Serviceability is a functional obsolescence “factor.” Together, each percentage can be summed to derive a measure of the sufficiency of a particular bridge or comparatively graphed to demonstrate a system’s overall sufficiency.

A ranking value can then be assigned for each structure by the structure’s total sufficiency versus other structures, or by a comparison of any singular factor of a network’s sufficiency ratings. This value would necessarily be assigned an integer value and would positively identify a structure’s replacement priority on a one-to-one basis. In other words, the bridge manager could begin to schedule replacements from absolute lowest sufficiency to highest sufficiency, or by ranking of a certain subset of the entire bridge population such as bridges posted lower than the allowable load for a school bus, or by other rankings.

ADT

Average annual daily traffic volume is an important indicator of the importance of a structure as it defines the level of service the structure provides and can indicate the expected amount of load cycling due to design loads and overloading. Therefore, a bridge system manager must include this important direct measurement of bridge use into his network prioritization model. The ABIMS Bridge Inspection Manual suggests that this value is the most recent counts available and is no more than two years old. Furthermore, the bridge system manager is instructed by ABIMS to develop a reasonable estimate, possibly from direct observation of traffic flow, if an existing or recent count is not available. ADT is coded in Table 4-2 on the following page as an integer assigned to a range of actual existing or estimated values.

30

Table 4-2. Coding for Various ADT Ranges

Code ADT Range

0 1 2 3 4 5

25000+ VPD 15000 to 24999 VPD 2500 to 14999 VPD 200 to 2499 VPD 50 to 199 VPD 1 to 49 VPD

The Average Daily Traffic (ADT) Codes and values for the selected study group are shown in Table 4-3.

Table 4-3. Average Daily Traffic Counts and ADT Codes for the Shelby County Group Study Structure Number ADT ADT Code

013-59-634Q 1200 3

093-59-581Q 900 3

334-59-595Q 100 4

446-59-601Q 200 4

020-59-538Q 250 3

034-59-544Q 350 3

103-59-584Q 150 4

086-59-578Q 352 3

078-59-611Q 800 3

017-59-536Q 1100 3

107-59-587Q 366 3

103-59-585Q 500 3

086-59-576Q 352 3

343-59-598Q 100 4

000-59-501Q 200 3

010-59-526Q 2250 3

491-59-606Q 400 3

068-59-565Q 3100 2

077-59-569Q 100 4

446-59-602Q 200 3

Roadway Classification

Functional classification, or “the grouping of highways by the character of service they provide” (AASHTO Green Book, 1990), is a means by which a bridge manager can initially prioritize the used of bridge replacement funds. Also, functional classification provides a means to characterize the level of service, and hence the expected frequency of loading and overloading of a system of

31

bridges. As noted previously, functional classification is measured and recorded as roadway classification in the BRPD essentiality for use factor. Functional classification is assigned an integer value based on the ALDOT Central Office Functional Classification maps. Table 4-4 lists available classification codes composing the BRPD Roadway Classification. This list is based on ABIMS Item 26 (ABIMS Bridge Inspection Manual, 1997); however, unlike the ABIMS table for this item, no separator for rural and urban is made. This simplifying assumption appears to be acceptable for categorizing and prioritizing LT20’s on a County-by-County scale, and requires additional review prior to applying the findings to more regionalized bridge networks. Descriptions of the AASHTO roadway classifications and the appropriate codes for each classification are shown in Table 4-4.

Table 4-4. Roadway Classifications

Code Description

5 4 3 2 1

Principal Arterial-Other than Interstate Minor Arterial Major Collector Minor Collector Local

The roadway classifications and resulting Roadway Classification (RC) Codes for the Shelby County Group Study are shown in Table 4-5.

32

Table 4-5. Roadway Classifications and RC Codes for the Shelby County Group Study

Structure Number Classification RC Code

013-59-634Q 3 3

093-59-581Q 2 2

334-59-595Q 1 1

446-59-601Q 1 1

020-59-538Q 2 2

034-59-544Q 1 1

103-59-584Q 2 2

086-59-578Q 1 1

078-59-611Q 1 1

017-59-536Q 3 3

107-59-587Q 2 2

103-59-585Q 2 2

086-59-576Q 1 1

343-59-598Q 1 1

000-59-501Q 1 1

010-59-526Q 3 3

491-59-606Q 1 1

068-59-565Q 3 3

077-59-569Q 1 1

446-59-602Q 1 1

Structural Adequacy

Structural adequacy is composed of structural condition ratings that qualitatively represent the remaining life and structural adequacy of the major structural elements of the bridge. The BRPD condition ratings, as noted earlier in this report, consist of integer ratings reflecting the subjective measurements of deterioration of the bridge deck, bridge superstructure, bridge substructure, and channel. For simplicity of grading, a separate rating for culverts is not included in the BRPD system; however, similar components of the culvert are graded accordingly. In fact, an aggregate “culvert” rating can be assigned to a structure by grading each of the three bridge structural elements (deck, superstructure, and substructure) and assigning an identical lowest score to every element.

Table 4-6 lists the various structural element grades and the resulting Structural Adequacy (SA) Codes for the Shelby County Group Study.

33

Table 4-6. Condition Ratings and SA Codes for the Shelby County Group Study Structure Number Deck Super Sub Channel SA Code

013-59-634Q 3 3 3 5 14

093-59-581Q 3 3 5 6 17

334-59-595Q 4 5 4 5 18

446-59-601Q 5 5 5 4 19

020-59-538Q 4 5 4 5 18

034-59-544Q 3 4 3 4 14

103-59-584Q 6 6 6 7 25

086-59-578Q 4 4 4 7 19

078-59-611Q 4 5 4 5 18

017-59-536Q 6 6 6 7 25

107-59-587Q 3 3 3 6 15

103-59-585Q 4 5 3 7 19

086-59-576Q 4 5 5 7 21

343-59-598Q 5 5 5 6 21

000-59-501Q 5 5 5 5 20

010-59-526Q 7 7 7 7 28

491-59-606Q 3 4 3 6 16

068-59-565Q 5 5 5 6 21

077-59-569Q 8 8 8 8 32

446-59-602Q 9 9 9 6 33

Load Rating

Unarguably the most visible and obvious contributor to a structure’s sufficiency rating is the load rating. However, this item seems to be virtually non-existent within the LT20 population in most Alabama counties. Load rating, and subsequently bridge posting based on rating, is performed on all NBIS structures within Alabama. This action reduces associated liability for structural deficiency, protects the traveling public, and allows less than full HS20-designed bridges to remain within the bridge network. Therefore, it is evident that posting of all bridges may be performed. The BRPD prioritization algorithm gives priority to those structures that are posted for loads less than maximum legal loads. Numerical values are assigned according to the range that the bridge falls below the maximum legal load. Table 4-7 shows the proper coding for various ranges of posting.

34

Table 4-7. Coding for Posting by Percent of Legal Load Code Posting by Percent of Legal Load

5 4 3 2 1 0

No posting. 58%-42% of Legal Load. 42%-33% of Legal Load. 32%-22% of Legal Load. 21%-14% of Legal Load. 13%-0% of Legal Load.

Table 4-8 shows the bridge inventory rating, or posted weight limit, and the Load Rating (LR) Codes for the Shelby County Group Study.

Table 4-8. Bridge Inventory Ratings and LR Codes for the Shelby County Group Study Structure Number Posting LR Code

013-59-634Q 3 0

093-59-581Q 3 0

334-59-595Q 7 1

446-59-601Q 12 3

020-59-538Q 12 3

034-59-544Q 36 5

103-59-584Q 12 3

086-59-578Q 36 5

078-59-611Q 36 5

017-59-536Q 36 5

107-59-587Q 36 5

103-59-585Q 36 5

086-59-576Q 36 5

343-59-598Q 36 5

000-59-501Q 15 3

010-59-526Q 36 5

491-59-606Q 36 5

068-59-565Q 36 5

077-59-569Q 36 5

446-59-602Q 36 5

Serviceability

Serviceability measures the functional characteristics of a given bridge against the functional characteristics of the approach roadway. Typically, the measure of serviceability relies only on vertical and horizontal clearance with respect to the level of service provided. Thus, serviceability is an independent measure of the degree of allowable functionality of a given

35

structure and is not dependent on the condition of the structure under consideration. As a result, FHWA has allowed the functional obsolescence of a structure to play a role in determining eligibility for replacement funds.

The BRPD prioritization algorithm measures the variance of bridge width from a desirable or allowable width based on existing roadway width and various County road system guidelines for roadway and bridge width. A bridge or roadway width less than 18 feet is coded zero. Furthermore, BRPD serviceability allows for a measure of the effectiveness of existing safety features on the bridge and along the approaches. Then, functionality and safety features are summed to measure total serviceability of the LT20 structure.

Table 4-9 shows the proper coding for various bridge and roadway widths, and Table 4-10 lists the quantitative value of existing safety features.

Table 4-9. Coding for Posting by Percent of Roadway Width and ADT

Code Bridge Width as a % of Roadway Width

5 4 3 2 1 0 0

125%+ and ADT 4,001+ VPD 124 to 116% and ADT 2,001 to 4,000 115% to 108% and ADT 751 to 2,000 107% to 100% and ADT 0 to 750 VPD >100%, ADT exceeds allowable range

Lane or Bridge Width <18 feet. <100%, any ADT

Table 4-10. Coding for Effectiveness of Existing Safety Features

Code Existing Safety Features

5 4 3 2 1 0

Existing features meet current standards and in good condition. Existing features meet standards but require repair or replacement. Existing features substandard but in good condition. Existing features substandard and require repair or replacement. Only advance warning and delineator signage in place. No safety features in place.

Table 4-11 shows the calculated results for percent bridge width, safety grades, and the combination Bridge Width and Safety Feature codes measuring serviceability for the Shelby County Group Study.

36

Table 4-11. Percent Bridge Width, Safety Grades, and BW+SF Codes for the Shelby County Group Study

Structure Number % Bridge Width Safety Grade BW+SF Code

013-59-634Q 93% 1 1

093-59-581Q 88% 1 1

334-59-595Q 83% 1 1

446-59-601Q 60% 1 1

020-59-538Q 126% 1 1

034-59-544Q 96% 1 1

103-59-584Q 96% 1 1

086-59-578Q 96% 1 1

078-59-611Q 100% 1 2

017-59-536Q 72% 1 1

107-59-587Q 100% 1 3

103-59-585Q 105% 1 3

086-59-576Q 100% 1 3

343-59-598Q 100% 1 3

000-59-501Q 117% 1 5

010-59-526Q 100% 1 2

491-59-606Q 121% 1 5

068-59-565Q 84% 1 6

077-59-569Q 118% 5 10

446-59-602Q 100% 5 10

Analysis of the Composite Sufficiency Rating

The equation for computing the composite sufficiency rating is a linear function that sums the raw component scores using the weighted percentages discussed earlier. The composite sufficiency rating equation is shown below. Normally, this value is reported as a real number with one place shown after the decimal. Computation of sufficiency ratings for the entire database can easily be accomplished using a spreadsheet or database program.

SUFFICIENCY = 2ADT + RC + 0.8333CR + 5LP + 3(BW+SF) [Equation 4.1]

The contributing data and use of Equation 4.1 are illustrated in tabular format shown in Tables 4-12 and 4-13, and in Figure 4-1 using a structure from the Shelby County LT20 bridge network.

37

Table 4-12. Required Bridge Information

Required Bridge Information

County Road 20 LT20 Bridge Structure Number 020-59-538Q

Span Length = 16 ft along centerline of roadway ADT = 300 vpd

30° Skew, Right Ahead Inventory Posting = 12 tons

Approach Roadway = 20 ft wide Minor Rural Collector

Bridge Width = 16 ft perpendicular to roadway centerline

Condition Ratings

Deck 4 Posting signs and bridge end delineators in place, no

Superstructure 5 guardrail or curbs. Substructure 4

Channel 5

Table 4-13. Component Code Computations

Computation Factor Computation Result

ADT = 300 vpd ADT Code = 3

Roadway Classified as a Minor Rural Collector RC Code = 2

Σ(Condition Ratings) = 4 + 5 + 4 + 5 CR Code = 18

Inventory Load Posting = 12 tons = 33% of Legal Load LP Code = 3

Bridge to Roadway Width Ratio = 75%, ADT = 300 vpd BW Code = 0

Roadway signs in place, no guardrail or bridge curbing SF Code = 1

Composite Sufficiency Rating Computation Using Equation 4.1

SUFFICIENCY = 2(3) + 2 + 0.8333(18) + 5(3) + 3(0+1) SUFFICIENCY = 41.0

Conclusion Under the guidelines of this report, this structure is eligible for replacement.

Figure 4-1. Example of a Sufficiency Rating Computation

38

The following table illustrates the individual codes contributing to the composite sufficiency rating and the calculated decimal value for the sufficiency ratings for the Shelby County Group Study.

Table 4-14. Sufficiency Codes and Composite Sufficiency Ratings for the Shelby County Group Study

Structure Number ADT RC SA LR BW+SF Sufficiency Rating

013-59-634Q 0 3 14 0 1 23.7

093-59-581Q 0 2 17 0 1 25.2

334-59-595Q 0 1 18 1 1 32.0

446-59-601Q 0 1 19 3 1 42.8

020-59-538Q 0 2 18 3 1 41.0

034-59-544Q 0 1 14 5 1 46.7

103-59-584Q 0 2 25 3 1 48.8

086-59-578Q 0 1 19 5 1 50.8

078-59-611Q 1 1 18 5 2 53.0

017-59-536Q 0 3 25 5 1 57.8

107-59-587Q 2 2 15 5 3 54.5

103-59-585Q 2 2 19 5 3 57.8

086-59-576Q 2 1 21 5 3 58.5

343-59-598Q 2 1 21 5 3 60.5

000-59-501Q 4 1 20 3 5 53.7

010-59-526Q 1 3 28 5 2 63.3

491-59-606Q 4 1 16 5 5 60.3

068-59-565Q 5 3 21 5 6 67.5

077-59-569Q 5 1 32 5 10 90.7

446-59-602Q 5 1 33 5 10 89.5

The Federal Highway Administration has interpreted the federal funding replacement threshold to be a sufficiency rating less than or equal to 50.0. Furthermore, the bridge under consideration must also be functionally obsolete or structurally deficient and functionally obsolete. Since the LT20 network of bridges is not currently considered for replacement, there are no guidelines for replacement. Therefore, the bridge manager is open to specify the replacement threshold for his network’s LT20’s. Without additional research, it is recommended that a sufficiency rating of 50.0 be implemented as an initial guideline.

39

Section 5 Replacement and Rehabilitation Case Studies

Replacement and Rehabilitation Case Studies

LT20’s typically represent significantly less replacement cost compared to NBIS bridges. The replacement of most LT20’s is generally conducted in the case of severe deterioration or failure since they represent a reduced safety hazard compared to the failure of NBIS bridges. Although the replacement cost of an LT20 is less than that of an NBIS bridge, the failure mode of LT20’s could potentially cause a more serious situation than mere driving inconvenience. With these issues in mind, safety is the most important motivation for utilizing timely and efficient replacement alternatives for these structures.

The responsibility of maintaining and replacing these structures currently rests squarely on counties and other local governments. Therefore, it is critical that funds are used in the most cost effective manner to ensure the replacement of as many structures as limited budgets will allow. An economic analysis of available designs and techniques, where a choice can be made, may always be conducted on a case-by-case basis. Non-engineering constraints may severely limit the alternatives available to the engineer for a specific project or location. Generally, the engineer has a wide range of materials and techniques to choose in selecting the most economical alternative.

Several factors are considered when conducting an economic and engineering analysis. These factors typically include the following: service life of the structure, initial project cost, cost of detours, traffic control and traffic safety features, cost to the traveling public for delays or extra travel distance due to road closures, initial cost versus maintenance costs for cleanout or repair, cost and performance of inlet and outlet treatments, and overall aesthetics.

In this section, case studies are used to outline the available replacement and rehabilitation alternatives and how they have been applied by local government agencies. The replacement alternatives using pipe were normalized for comparison by choosing sites that required double lines of 72” or equivalent diameter round, arch, or box structures. Cover depths, site hydrology, and tailwater conditions were roughly equivalent. Excavation and replacement was the most common technique of repairing LT20 structures, followed by installation of liners. The case studies include the following:

• Replacement Using Reinforced Concrete Piping Materials (circular, arch and box shapes)

• Replacement Using Metal Pipe (circular and arch shapes) • Rehabilitation Using Glue Laminated Timber Deck Panels • Rehabilitation Using Metal and Plastic Liners

40

• Replacement Using Precast Span Sections • Replacement Using Steel Beams with a Cast in Place Concrete Deck

These case studies introduce the most economical and time-effective techniques available and recommendations are made on their use on a case-by-case basis. The cost data compiled in these case studies were produced from data collected from participating counties and may vary due to factors such as material availability, labor cost, equipment cost and location. None of the analyses performed includes the cost of on-site detours that are required in some cases. It is noted that alternatives that eliminate the need for detours are very beneficial and result in cost savings due to reduced project time, equipment, and material cost. It is also noted that other replacement alternatives using other materials are available but were not covered as part of this research. Projects were limited to those previously conducted by participating agencies. The projects in this report were selected based on similar opening areas, cover depths, and length of structures. Each material, however, possessed unique advantages and disadvantages that require engineering judgment during the selection process and may vary substantially depending on the particular geographical region of application.

It is not the intent of this section to develop a cost guideline to all available products or techniques but to compare and bring to light some of the practical and cost effective techniques for the replacement of LT20's used by local governments and to develop a cost model for use in the prioritization process for a network of LT20's.

Replacement Using Reinforced Concrete Pipe

Reinforced concrete piping material has proven to have a longer service life than any feasible replacement material used in the current state-of-practice. Concrete piping material can have circular (RCP), arch or span-rise (RCAP) or box shaped (RCBC) geometry. Concrete piping has superior impact resistance and is not sensitive to excavation loads. However, it has been well recognized that concrete material is susceptible to chemical and biological attack. The smooth concrete surface contributes to superior hydraulic performance with a low Manning coefficient or Manning’s “n” which is a function of the material. The Manning’s coefficient for finished concrete is 0.011- 0.013 based on past test on flow over finished concrete surfaces.

Concrete pipe requires minimal trench widths, and the compaction of the backfill material is not as critical as that required for metal pipe. Too little compaction results in insufficient lateral support, and metal pipe may deform beyond the specified limits under full external loading before concrete, under the same conditions. Concrete pipe is heavier requiring shorter sections and more joints than flexible pipes. The proper placement of concrete pipe can be time consuming. Each pipe link must be laid with precision in order for each joint to “bell-up” properly as shown on the following page in Figure 5-1. If the links are not correctly jointed together infiltration and settlement of the roadway will occur.

41

Figure 5-1. Laying Reinforced Concrete Arch Pipe with a Trackhoe

Although the links require more quality control during construction, the means in which concrete pipe is laid can prove to be valuable. In many cases existing structures can be excavated and removed one lane at a time. The existing structure is first cut from within at the centerline. This allows the existing structure to be cleanly removed without causing disturbance to the remaining lane that is occupied by controlled traffic flow. The joints allow the concrete pipe to be placed in segments without the closure of traffic flow. This technique saves the cost of constructing onsite detours or rerouting traffic along a lengthy alternate route.

The replacement costs of several LT20 structures using concrete piping materials were determined. Projects were identified that utilized all of the available concrete pipe shapes. For comparison purposes, projects were identified that had similar cross sectional area with an opening area typical of LT20’s. Projects cost using circular, arch and box shaped concrete piping were investigated, and the summary cost of each is shown in the Table 5-1.

Table 5-1. Summary of Replacement Cost Using Concrete Pipe

Type of Construction Personnel Equipment Misc. Materials Piping Materials Total

RCP with headwalls $ 11420 $ 10680 $ 10802 $ 10549 $ 43451

RCP projecting from fill $ 6180 $ 12440 $ 7864 $ 14506 $ 40990

RCAP with headwalls $ 11420 $ 10680 $ 10802 $ 15342 $ 48243

RCAP projecting from fill $ 6180 $ 12440 $ 7864 $ 21095 $ 47579

RCBC with precast wing walls $ 8540 $ 10680 $ 8854 $ 14976 $ 43050

RCBC projecting from fill $ 6660 $ 12440 $ 7114 $ 20670 $ 46884

42

In general, RCBC’s (reinforced concrete box culverts) with precast wing walls were the most economical for the equivalent cross sectional area compared to the overall cost and time of construction of other shapes of concrete pipe. Itemized detailed cost analysis for each of the construction types using concrete pipe are shown in Tables F-1 through F-6 in Appendix F. Arch (span-rise) shapes are appropriate for sites with limited cover or overfill or where these shapes are more appropriate for site conditions. Arch pipe may also increase hydraulic performance compared to circular concrete pipe.

Cost comparisons were made between headwall and projecting from fill end treatments for each type of concrete pipe as shown in Figures E-1 through E-4 in Appendix E. Figure 5-2 below summarizes these cost comparisons.

$0

$10,000

$20,000

$30,000

$40,000

$50,000

$60,000

Circular Concrete Pipewith Headwalls

Circular Concrete PipeProjecting from Fill

Concrete Arch Pipe withHeadwalls

Concrete Arch PipeProjecting from Fill

Labor Equipment Misc. Materials Piping Materials

Figure 5-2. Cost of Circular and Arch Shaped Reinforced Concrete Pipe with Headwalls or Projecting from Fill

Pipes with headwalls and projecting from fill are both commonly used in construction. The use of headwalls provides support for shoulder slopes against erosion as well as increasing hydraulic performance of the structure. Maintenance efforts are also reduced with the use of headwalls by decreasing the need for erosion control and shoulder slope maintenance as shown in Photo G-15 in Appendix G. Replacement using pipe projecting from fill requires additional pipe length compared to projects using headwalls since additional pipe length is necessary to construct and

43

maintain fill slopes. This additional pipe can add considerable cost to the overall project (Figures 5-2 and 5-3). With limited right-of-way in some locations, it is often difficult to stay within the boundary of the right-of-way with the additional length of pipe required to construct proper shoulder slopes. Headwall construction requires higher labor costs because of formwork and concrete placement than are required for circular and arch shapes as shown in Photo G-14. Precast boxes are faster, easier and safer to install than cast-in-place systems of the same geometry.

Precast boxes are manufactured in a wide range of standard sizes that include multi-cell units and mega-boxes (spans exceeding 14 feet). Two types of reinforcement patterns are available depending on the amount of cover depth. ASTM C 789 precast boxes are specified when cover depths exceed two feet. ASTM C 850 precast boxes are specified when cover depths are less than three feet. Time and cost saving are achieved when precast boxes are used compared to circular and arch shaped concrete pipe when the end treatment of the structure include a headwall (Figure 5-3).

Figure 5-3. Replacement Cost Using Concrete Pipe with Headwalls

These savings are achieved with the use of “bolt-on” precast wings and parapets that are available for box shapes (Photo G-18 and G-19). Costs of using precast boxes projecting from fill increase considerably due to the increased length required to provide the proper shoulder slopes (Photo G-20). Compared to all available concrete pipe shapes, concrete boxes have several advantages. Boxes may be used in locations with limited cover because of their rectangular shape. Various sizes are available for selection based on specific site conditions.

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

$50,000

Circular Concrete Pipewith Headwalls

Concrete Arch Pipe withHeadwalls

Concrete Boxes withHeadwalls

Labor Equipment Misc. Materials Major Structural Material

44

Construction is fast and simple with the use of four-foot tongue and groove links (Photo G-17). Precast wings and parapets are bolted on to the end box section with minimal effort and time. Concrete boxes are generally preferred compared to circular and arch shaped concrete piping due to speed of construction resulting in reduced project costs.

Total Replacement Using Metal Pipe

In many replacement efforts, metal pipe is used to replace existing deteriorated LT20 structures. As indicated by past documented experiences, the field service life of metal pipe has proven to be shorter than that of reinforced concrete pipe (Photo G-10). While most metal pipe has a life span of approximately 30-40 years, it has an overall reduced cost of 65-75% compared to that of reinforced concrete pipe. Typically metal pipe is manufactured using a process in which the pipe is rolled through a series of cold-formed molds or rollers that create waves or corrugations in the material. These corrugations affect the hydraulic performance by increasing the Manning coefficient or Manning’s “n”. This coefficient is used in the Manning’s equation, an empirical equation that determines flow characteristics of fluid through a particular geometry. The Manning’s coefficient is a direct function of the roughness of the piping material used. The Manning’s coefficient for corrugated metal averages 0.022 based on past tests on flow over corrugated surfaces.

The overall effect measured by the performance cost, availability and ease of construction often contributes to the selection of metal pipe during replacement. With limited equipment capacities, the benefit of reduced weight compared to concrete is often necessary in order to perform replacements using “in-house” available equipment and labor. In order to evaluate the cost of replacement using metal pipe, a typical replacement effort was tracked and each of the contributing expenditures were documented. Projects using various types of metal pipe and end treatment construction were investigated. The initial cost of a project using metal pipe is less than a project using concrete pipe due to the savings in the piping material and equipment cost. Comparison using metal pipe was investigated on both circular (GMP) and arch (GMAP) shaped galvanized metal pipe and asphalt coated arch shaped metal pipe (ACAP). The summary of the cost of the projects is shown in Table 5-2.

Table 5-2. Summary of Replacement Cost Using Metal Piping

Type of Construction Personnel Equipment Misc. Materials Piping Materials Total

GMP with headwalls $ 11420 $ 10680 $ 10802 $ 3067 $ 35970

GMP projecting from fill $ 6180 $ 12440 $ 7864 $ 4217 $ 30701

GMAP with headwalls $ 11420 $ 10680 $ 10802 $ 7104 $ 40006

GMAP projecting from fill $ 6180 $ 12440 $ 7864 $ 9768 $ 36252

ACAP with headwalls $ 11420 $ 10680 $ 10802 $ 9115 $ 42017

ACAP projecting from fill $ 6180 $ 12440 $ 7864 $ 12533 $ 39017

Piping material costs using metal pipe are typically reduced by 71% and 46% for circular and arch shapes, respectively, compared to concrete pipe costs (Figures E-11 and E-12 in Appendix

45

E). Graphical representations of the cost of each of the metal pipe replacement alternatives are shown in Figures E-7 and E-8. Figure 5-4 on the following page is a summary graph of the variance in costs between each end treatment alternative.

Although alternatives including headwalls are more expensive and time consuming the use of headwalls greatly improves the hydraulic performance and reduces erosion potential and required maintenance efforts. The itemized cost analysis of metal pipe is shown in Table F-7 through F-12 in Appendix F.

Figure 5-4. Replacement Cost Using Galvanized Metal Pipe with Headwalls or Projecting from Fill

Arch shapes are typically used in areas where these shapes are more appropriate for site conditions with minimal cover depth. Metal pipe can be laid using a standard backhoe, which is generally available in most counties or municipalities. Due to the increased weight of concrete pipe a larger track hoe is required to unload and lay piping materials greater than 24 inches in diameter. Metal pipe sizes range from 24-inch to 120-inch diameter.

While easier to handle, metal pipe requires a wider trench and more careful backfill and compaction than concrete pipe. Too little compaction may result in insufficient lateral support, and metal pipe may deform beyond the specified limits under full external loading. Too much compaction during installation of any piping material may cause excessive deformation, squaring, or even collapse.

The anticipated maintenance free service life of metal pipe is primarily a function of the corrosivity and abrasiveness of the environment into which the pipe is placed. Corrosive potential must be determined from the pH and minimum resistivity tests covered in California Test 643.

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

Plain Galvanized MetalPipe with Headwalls

Plain Galvanized MetalPipe Projecting from Fill

Plain Galvanized MetalArch Pipe with

Headwalls

Plain Galvanized MetalArch Pipe Projecting

from Fill

Labor Equipment Misc. Materials Piping Materials

46

Abrasive potential must be estimated from existing bed material and anticipated flow velocities. Electrical resistivity measurements are used as an indication of the corrosion potential of the bed material. As a rule, the higher the electrical resistivity of the bed material the less corrosive potential it possesses. Materials having resistivity values of 2,000 ohm-cm or higher are classified as non-corrosive.

In an environment with minimal corrosive and abrasion potential or on a roadway with an anticipated change in traffic conditions that may warrant the future adjustment of the roadway alignment, metal pipe is determined a feasible replacement option. Consideration of alternative designs is necessary to achieve the required design service life when potentially threatening environmental factors are present. Alternative designs may consist of increased metal thickness or the use of protective coatings.

Galvanizing is satisfactory protection under most conditions; however, the presence of corrosive or abrasive elements may require additional protection. Increasing the metal thickness can achieve additional service life in abrasive conditions. Since 1.3-mm thickness is the minimum steel pipe that the California Department of Transportation allows, it must be used only in locations that are nonabrasive.

Approved protective coatings include: bituminous, which is hot dipped to cover the entire inside and outside of the pipe; asphalt mastic and polymeric sheets, which can be applied to the inside and/or outside of the pipe; and polymerized asphalt, which is hot dipped to cover the bottom 90% of the inside and outside of the pipe. Recently developed coating products such as polymerized asphalt can provide superior abrasive resistant qualities that surpass bituminous coatings of similar thickness by as much as 10 times. However, field tests have not been developed to prove the anticipated increased service life under various long-term exposures to potentially harmful environments.

Project costs using metal circular and arch pipe with each of the above types of coatings are shown in Table 5-2. Both headwall and projecting-from-fill end treatments were investigated when using metal pipe. Concrete pipe cost savings is achieved when projecting from fill end treatments are used (Photo G-16). As shown in Figures E-7 and E-8, the reduced cost of metal piping material compared to concrete allows the overall project cost to be lower without the use of headwall end treatments when using metal pipe. When metal pipe is chosen as the replacement material factors such as abrasion and corrosion potential are considered and the material selection or coating reflects these factors in order to obtain the maximum service life.

Rehabilitation Using Slip Fit Lining Techniques

Rehabilitation of LT20 structures may be a viable option when cover depths are large, and when on-site or alternate-route detours are not economical. The factor of utmost concern when selecting liners to rehabilitate or essentially replace an LT20 structure is the hydrology of the drainage area that the structure serves. Since the structure size is based on future storm events, the occurrence and magnitude of which cannot be precisely forecasted, the engineer must resort to statistics to define the design discharge.

47

Design floods can be defined in terms of probability or return period (recurrence interval). Return period or recurrence interval (the “N-year flood”) and probability (p) are reciprocals, that is, p=1/N. Therefore, a flood having a 50-year return frequency (Q50) is commonly expressed as a flood with the probability of recurrence of 0.02 (2% chance of being exceeded) in any given year. Thus, an agency must first establish an acceptable risk, or return period by specifying a design flood frequency.

There are two recognized alternatives to establishing an appropriate design frequency. This is determined by policy and engineering combined with economic analysis. The objective of designing an LT20 structure provides optimum performance by considering function versus cost rather than to just meet the minimum design criteria. This is performed by considering a range of peak flows and the design flood is selected which best satisfies the specific site conditions and associated risks. Therefore, an evaluation of the inherent flood-related risks to upstream and downstream properties, the roadway, and to the traveling public are performed.

Highway classification is one of the important factors in establishing an appropriate design flood frequency or return. If a structure is designed to accommodate the worst possible flood event it is usually too costly to be justified. Typically LT20 structures are designed for a 25-year return period and checked for excessive effects on the roadway for a 50- and 100-year return period. Because of constraints caused by existing structures this return period may be severely limited or not satisfied in many instances, negating the possibility of reducing the cross section by using liner techniques. However, in many cases it may be determined that the existing structure exceeds the capacity required by the design flood frequency. When this is the case liners can prove to be a feasible technique for the rehabilitation or replacement of LT20 structures.

The first step in selecting a liner size and type after determining the minimum opening size required is to measure cross sections along the existing pipe every five feet along its length. This will determine the maximum pipe size that can be inserted into the existing structure. The piping material is also dependent on limitations of opening size. If the existing opening size can be reduced considerably, reinforced concrete pipe may be used as the liner. If the opening reduction must be kept to a minimum, galvanized or aluminized metal pipe is used. Ultra-Flo aluminized pipe is often used where reductions in opening size is critical to the performance of the structure. This material is constructed using special low-rise ribs unlike typical corrugated metal piping. This offers an extra smooth surface with a tested Manning’s “n” coefficient of 0.012, which compares to the average roughness of concrete pipe. Although the price is typically higher than other metal piping materials the benefit of the 0.012 Manning’s n may be essential to conform to the hydraulic requirements of certain structures.

After the determination as to which piping material will be used, the selected pipe is pushed or pulled into the existing structure using a backhoe as shown in Figure 5-5.

48

Figure 5-5. Pulling Liner Inside Existing Pipe

Skids or runners (angle iron or old guardrail) may be used to guide the pipe as it is placed inside the existing opening. After the liner pipe is placed, the area between the new and old pipe is sealed off at the ends using concrete or sandbags. When concrete is used it is typically placed two to three feet deep the along the perimeter of the ends leaving a small void with a cone type shape at the very top of the pipe. This void is used to pump the grout or flowable fill material into the residual space between the new and old structure. After the backfilling is complete end conditions and shoulder construction are performed similar to a typical total replacement (Photo G-22). A summary of the project cost using the slip fit liner technique is shown in Table 5-3.

Table 5-3. Summary Cost of Rehabilitation Using Liner Pipe

Type of Construction Personnel Equipment Misc. Materials Piping Materials Total

12 Gauge Double Walled Aluminized Ultra Smooth Flow Liner Pipe

$ 3240 $ 1820 $ 4870 $ 11220 $ 21150

Advantages of using liner techniques are numerous. The downtime of the roadway due to alternate routing or costs of constructing detours is totally eliminated. Structures can be replaced using “in house” equipment and labor which otherwise might have been impossible performing excavation that is required for total replacement. Using liners significantly reduces labor and equipment costs as shown in Figures E-16 and E-17. A summary of these comparative costs is shown in Figure 5-6.

49

Figure 5-6. Cost of Rehabilitation Using Liners vs. Replacement Using Concrete or Metal Pipe

Rehabilitation Using Glue Laminated Timber Deck Panels

Advances in engineered timber materials, bridge design, and component fabrication allow for bridge projects that cost less, save time and provide longer-lasting quality than conventional timber structures. During the late 1970’s and throughout the 1980’s, treated timber fabricated into innovative, modern designs has received increasing attention by structural engineers and county decision makers. The modern timber bridge is the focus of a national initiative funded by Congress through the Unites States Department of Agriculture (USDA) Forest Service.

Bridges made of treated timber are not new, but the modern use of treated timber in engineered, prefabricated bridge components is new. Researchers have developed innovative, cost-effective applications for treated timber in small bridge construction over the last 15 years. These designs include solid lumber and new wood products such as glue-laminated and laminated veneer lumber, manufacturing of factory-made timber bridge components, and shipping of completed components for assembly at the bridge site.

Most modern timber bridge designs emphasize bridge deck systems that can be installed on timber, steel, or concrete foundations. Industry experts anticipate that properly treated engineered timber materials have an effective lifespan of more than 60 years. Total replacement using timber material was not observed in the case study. However, rehabilitation was performed on an existing LT20 timber structure using glue-lam timber deck panels (Figure 5-7).

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

Rehab Using Liners Circular Concrete PipeProjecting from Fill

Plain Galvanized Metal PipeProjecting from Fill

Labor Equipment Misc. Materials Piping Materials

50

Figure 5-7. Rehabilitation Using Timber Glue Laminated Panels

Glue laminated structural lumber is a stress rated, structural lumber glued together by machine to form beams or deck panels. Glue laminated components are factory-made to precisely engineered specifications and treated before being shipped to the job site.

The subject structure’s deck was deteriorated beyond repair, while the abutments and other substructure were in sound structural condition. Therefore, the existing deck was removed and replaced using pre-fabricated glue-laminated deck panels. This process took only a day, using smaller and less expensive erection equipment than typically required for concrete construction.

The cost of this rehabilitation is significantly less compared to total replacement of the structure using any type of available materials. The cost of the project compared to other optional replacement materials and techniques is shown in Figures E-14 and E-15. A summary of the project cost to rehabilitate a timber structure using glue laminated timber deck panels is shown in Table 5-4.

Table 5-4. Cost Summary of Rehabilitation Using Glue Laminated Timber Panels

Type of Construction Personnel Equipment Misc. Materials Timber Panels Total

Rehabilitation using Glue Laminated Timber Deck Panels $ 4280 $ 1390 $ 760 $ 11376 $ 17806

Thus, modern timber bridges can be an economical alternative. Bridge costs vary and tend to be site-specific, but the construction characteristics of timber, coupled with modern timber bridge

51

performance, can make these bridges a competitive option in the replacement of LT20 structures. Wood is lighter than most bridge materials, which allows lighter construction equipment to be used for installation. Also, existing substructures can usually accommodate lighter bridge weights. These factors can lead to large savings in construction.

Although timber components can be used in total replacement efforts (including the abutments) it is the general practice of most agencies to use concrete in the construction of the substructure when totally replacing an existing structure.

Replacement Using Precast Concrete Span Sections

Most LT20’s can be replaced using culvert materials with box, arch or circular shaped geometry. These materials offer cost effective solutions by considerably reducing material and labor cost compared to conventional bridge construction. Although some cases require more conventional bridge designs, general conditions may not permit the use of piping materials or materials described to have an invert. This is governed by many factors such as the depth of the flow line or the quality of the bedding material beneath the structure.

In areas where a Federal Emergency Management Agency (FEMA) floodway is present, the floodway must be spanned with minimal restriction. When the replacement of an LT20 possesses this requirement, the cost of replacement drastically increases due to the additional construction time and equipment required. A precast concrete panel bridge is one of several design alternatives that can be used to effectively span the floodway.

Precast concrete span sections are used frequently in the replacement of bridges spanning less than 40 feet. The detailed replacement cost using an 18-foot precast concrete span section is shown in Table F-14. A summary of the cost of replacement using precast concrete span sections is shown in Table 5-5.

Table 5-5. Summary of Replacement Cost Using Precast Concrete Span Sections

Type of Construction Personnel Equipment Misc. Materials

Deck and Superstructure

Materials Total

Replacement using Precast Concrete Span Sections $ 31380 $ 43420 $ 28908 $ 14196 $ 111784

Precast concrete offers durability and 80- to 100-year service life expectancy. Construction time and cost are also reduced considerably compared to that of replacement using cast in place concrete due to the form work required for cast in place construction. After a complete engineering analysis of the soil conditions abutments are designed and constructed, as shown in Figure 5-8.

52

Figure 5-8. Typical Cast-in-Place Abutment for Precast Concrete Deck Sections

The three and half foot wide precast span sections are set in place along the abutment using a crane (as shown in Photos G-25 and G-26 in the appendix), jointed together with a lock and key joint system, and bolted together as they are set. Parapets or barrier rails are attached to the exterior span section as shown in Figure 5-9.

Figure 5-9. Setting Precast Concrete Span Sections

53

Material cost of construction for precast span sections is compared to replacements using concrete piping material in Figures E-20 and E-21. However, the cost of constructing the abutments for the precast span section greatly increased the labor and equipment cost of a replacement due to the increased construction time. In almost all cases, a replacement of this type requires a detour route or onsite detour to maintain traffic due to the extended construction period. Unlike replacement using piping materials the area necessary to stage equipment and materials is much larger for the construction of the required abutments.

Replacement Using Steel Beams with a Cast in Place Concrete Deck

When replacement using a bridge type construction is required, many agencies use steel beam construction with a cast in place deck. Most LT20’s can be replaced using what is typically described as culvert materials with box, arch or circular shaped geometry as described previously, but when these options aren’t sufficient other replacement options more analogous with typical bridge construction must be used.

Similar to the construction of LT20’s using precast span sections, construction using steel beams with a cast in place concrete deck can be relatively inexpensive for the replacement of an LT20. The concept of using steel beams with a cast in place deck is one of the most readily used methods in bridge construction. The detailed replacement cost of an 18-foot LT20 is shown in Table D-16. The material cost of replacement using steel beams is relatively lower than using precast concrete alternatives (Figures E-18 and E-19). However, forming materials and labor required for the construction of the concrete deck greatly increase costs.

A summary of the costs of replacement using steel beams with a cast in place concrete deck is shown in Table 5-6.

Table 5-6. Summary of Replacement Cost Using Steel Beams with a CIP Concrete Deck

Type of Construction Personnel Equipment Misc. Materials Deck and Superstructure Materials Total

Replacement using Steel Beams with a CIP Concrete Deck $ 36480 $ 45920 $ 28758 $ 7450 $ 118608

After a complete engineering analysis of the soil conditions, abutments are designed and constructed. The steel beams are set in place along the abutment using a crane or track hoe and jointed together with diaphragm bracing. Formwork is constructed between and along the steel beams for the deck. Labor cost and equipment cost of a replacement of this type is due to the construction time required for abutment construction and the formwork required. In almost all cases of replacement of this type a detour route or onsite detour is required to maintain traffic due to the extended construction period. Unlike replacement using piping materials the area necessary to stage equipment and materials is much larger for the construction of the required abutments. If maintained properly the service life for a structure of this type is typically 60 to 80 years.

54

Summary of Case Study Findings

Case studies were used to determine the relative cost of typical replacement alternatives commonly used on LT20’s. Recent bridge replacement sites were identified, investigated, and compared. This cost data was used to formulate cost models for use in replacement prioritization as well as an overall budgeting tool. These case studies were developed from data collected in numerous replacement and rehabilitation projects performed by county forces and contract labor. These projects were identified based on similar opening sizes, hydrology, cover depths, and roadway widths. Advantages and disadvantages of each of the case study projects were identified. Table 5-7 is a summary table of the replacement alternative that were determined to be the most effective and overall preferred method of replacement according to the data collected in the case studies performed.

Table 5-7. Summary Costs of Preferred Replacement Alternatives

Type of Construction Personnel Equipment Misc. Materials

Structural Materials Total

RCBC with precast wingwalls $ 8540 $ 10680 $ 8854 $ 14976 $ 43050

12 Gauge Double Walled Aluminized Ultra Smooth Flow Liner Pipe $ 3240 $ 1820 $ 4870 $ 11220 $ 21150

Replacement using Precast Concrete Span Sections $ 31380 $ 43420 $ 28908 $ 14196 $ 111784

When metal piping is used the material cost is typically reduced by approximately 71% and 46% for circular and arch shapes, respectively, compared to concrete. Reinforced concrete box culverts are the most economical alternative of all the concrete shapes due to the use of precast wingwalls and parapets. The cost of the labor and materials required for the formwork for headwall construction greatly increases the project cost of using circular or arch shaped concrete pipe. Pipe projecting from fill inflates project cost due to the increased length of pipe required to build maintainable shoulder slopes. Headwalls improve the hydraulic performance of the structure by decreasing entrance losses. Maintenance efforts are also reduced that would otherwise be required to prevent erosion without the use of headwalls.

It is notable that replacement alternatives using liner techniques allow reductions in cost due to the elimination of costly detours or excessive excavation due to deep cover depths. Project costs can be reduced by 50% or more; therefore, it is recommended to investigate possible opening size reductions for potential use of liner replacement.

Only in special cases where floodway considerations require precast concrete span sections or steel beams with a cast in place concrete deck, excessive costs result in increased time, equipment, and labor cost.

55

Section 6 Bridge Replacement Prioritization Methods

Data Management

After the acquisition of data and before the input and prioritization of data, it is necessary to systematically organize and file all hardcopies of inspection data. In this way, historical data sets can be established and maintained in an organized manner. NBIS bridge inspectors are typically well versed on the importance of maintaining a properly organized filing system. As a result, the ALDOT Alabama Bridge Inspection Management System (ABIMS) manual dedicates an appendix to adequately defining the requirements of this task.

A similar but separate filing system can be adapted to an LT20 bridge network with little additional effort on the part of active bridge inspectors. Procedures for preparing a filing system are adequately covered in the ABIMS manual. Thus, no procedure is included herein.

The Classifying of Condition States

Use of a Markov chaining function requires the defining of discrete condition states within a studied system. Since the backbone of the LT20 inspection system is based on the discrete condition ratings of a bridge’s structural elements, the LT20 inspection system can easily be incorporated into a Markov chaining function. For the following discussion on the Markov chaining function, a “condition state” is defined as a unique rating of the condition of a single major structural element on a subject bridge or on similar elements of an entire bridge network. By defining the Markov condition states in this way, a bridge network manager can begin to account for the variance of decay over time in his network of bridges.

The Markov Chaining Function

The Markov transition matrix for a bridge or system of bridges is composed of the transition probabilities for the condition rating of a single element or the entire structure. This matrix can be used to describe a bridge or the entire population of bridges within a managed network. The initial form of the transition matrix can be simplified since it is generally accepted that deterioration is a one-way system. Improvement of the condition ratings cannot be accomplished without work being performed on the system; thus, all elements of the form pji are zero. Therefore, no transition to higher states is allowed within the transition matrix. (Cesare, et al, 1991)

56

P

p 99

0

0

0

0

0

0

p 98

p 88

0

0

0

0

0

p 97

p 87

p 77

0

0

0

0

p 96

p 86

p 76

p 66

0

0

0

p 95

p 85

p 75

p 65

p 55

0

0

p 94

p 84

p 74

p 64

p 54

p 44

0

p 93

p 83

p 73

p 63

p 53

p 43

p 33

p 99p 99

[Equation 6.1]

The nature of this matrix can further be simplified by assuming that during a given period of study, i.e., a one-year or two-year inspection cycle, only a single transition of state is allowed. This assumption has been shown to be valid since the probability of a condition state deteriorating more than one state in a short time period (one to two years) has been shown to be negligible. The Markov transition matrix then becomes a banded matrix of the probability of an initial state passing to the next adjacent state (Cesare, et al, 1991). A banded matrix is a matrix having zero elements except along a band that runs diagonally through the matrix. Usually, but not always, this band is centered about the principal diagonal of the matrix (Gere & Weaver, 1983). Thus, the Markov transition matrix for a bridge or system of bridge can be simplified as follows.

Ρ

p 9

0

0

0

0

0

0

1 p 9

p 8

0

0

0

0

0

0

1 p 8

p 7

0

0

0

0

0

0

1 p 7

p 6

0

0

0

0

0

0

1 p 6

p 5

0

0

0

0

0

0

1 p 5

p 4

0

0

0

0

0

0

1 p 4

1

p 9p 9

[Equation 6.2]

This transition model has been found to effectively represent the transition of condition ratings for a structure or system of structures. Specifically, seven discrete states are generally recognized as the maximum number of states prior to reaching an absorption point, or a state that cannot be altered, in the above matrix. This simplification is possible since a condition rating of 3 is generally the acceptable trigger point for replacement for bridge structures. Any further transition to lower condition ratings requires immediate action or closure of the subject structure (Jiang et al, TRB 1180).

To estimate a future condition state, it is necessary to know the initial condition state and the probability of transition between states. The initial condition state of a new element is generally defined as the highest attainable state, or the “new” condition state of nine. This state can be represented in matrix form, as shown in Equation 6.3. (Cesare, et al, 1991). Initial condition states other than new can be defined by moving the unity term to other places in the column and replacing the unity with zero.

57

q 0 1 0 0 0 0 0 0( )

[Equation 6.3]

It has been shown that as the period of application of this initial condition state equation approaches infinity, a constant transition state is reached. Thus, a stationary process for the given total distribution is defined, and the resulting condition rating at year n may be found. (Cesare, et al, 1991)

q n q 0 Pn.PP

[Equation 6.4]

Where qn = probability of a given condition rating at year n P = matrix of transition probabilities qo = given condition rating at year 0

To use this equation, the matrix of transition probabilities must be determined. Several methods have been previously used to populate the transition matrix. Initial data available to assemble this matrix is often not available or complete for the LT20 bridge population. Therefore, a parallel transition probability matrix must be derived and used until enough data for the native LT20 population has been compiled. Therefore, the NBIS bridge data becomes a logical source for predictions of decay that parallel the LT20 population.

One such method allows the error between existing and estimated data to be corrected for bridge age within a given population of bridges of a condition rating. First, an overall minimization of error between the existing and estimated data is made. This is accomplished by minimizing the summation of the squared differences between the relative frequency and the discrete distribution. The number of bridges of age n weights each term in the total error.

P min

1

7

i 1

N

n

f i.n q o Tn.2

C n.

==

P min

1

7

i 1

N

n

f i.n q o Tn.2

C n.

==

P min

1

7

i 1

N

n

f i.n q o Tn.2

C n.

==

[Equation 6.5]

Subject to 0 < Tkk < 1

Where q0 = initial distribution fi, n = relative frequency of bridges at age n in state I T = matrix of transition probabilities N = # years of available data

Recognizing that only one state transition is statistically meaningful per inspection period, the above equation can be reduced to the following.

58

P min

1

N

n

f i.n q 0 TN.2

=

P min

1

N

n

f i.n q 0 TN.2

=

P min

1

N

n

f i.n q 0 TN.2

=

[Equation 6.6]

Thus, this statistical correction is very useful within a population of bridges of various age groupings. However, as with any analysis of statistical variance, a very large population is required for the correction to be meaningful. Therefore, the application of this correction is beyond the current scope of this project.

Another use of the transition matrix is in predicting the remaining service life of a structure. In an equation similar to the above equation, minimizing the absolute difference between the expected value of the condition rating and the actual average condition rating reduces error (Jiang & Sinha, 1989).

Additional applications of the Markov transition matrix include future predictions of condition ratings of a group of bridges, predicting costs and benefits of a replacement policy, and predicting future costs or risks for a single structure. To predict the future condition ratings of a group of bridges, the number of structures is held constant and Markov chains are applied to the relative frequency of the condition ratings.

Also, Markov chains can effectively model the effects of repair or replacement policy on a group of bridges. For instance, assuming a 20% per year replacement of all bridges in condition state two and three results in the following identity matrix. Then, this modified matrix can be applied to the known transition states to model the effect of the given replacement policy. Thus, the effect of bridge replacement policy decisions can be modeled by the Markov approach.

p 9

0

0

0

0

0

0.2 p 3.

0.2 p 2.

1 p 9

p 8

0

0

0

0

0

0

0

1 p 8

p 7

0

0

0

0

0

0

0

1 p p

p 6

0

0

0

0

0

0

0

1 p 6

p 5

0

0

0

0

0

0

0

1 p 5

p 4

0

0

0

0

0

0

0

1 p 4

0.8 p 3.

0

0

0

0

0

0

0

1 p 3

0.8 p 2.

Figure 6-1. Identity Matrix Model for a 20% Replacement Policy

In summary, Markov chains have been incorporated into recent versions of bridge management systems such as PONTIS and BRIDGET. The incorporation of the Markov process into these programs is based on the assumption that deterioration is a stationary process. Thus, these

59

systems assume that condition state changes are not dependent on past history and that transition probabilities are constant (DeStefano and Grivas, 1998). However, it is evident that allowing the chain to correct as additional inspection data is collected can enhance the overall performance of the model.

Application of the Markov Transition Matrix to Existing Condition Ratings

The purpose of incorporating the Markov transition matrix into this research has previously been stated as allowing the bridge manager to predict future sufficiency ratings and to anticipate the effects of bridge replacement decisions on a given bridge network.

As a demonstration of the modeling technique, the substructure matrix for Shelby County is shown in Figure 6-2. To make this demonstration meaningful, any values of unity other than for a condition rating of 2 have been changed to 0.9999 and any values of zero have been changed to 0.0001. This allows for a minute, yet acceptable, error of probability to produce a matrix other than the null matrix.

The values shown in this matrix are a weighted average of four years of substructure condition ratings variance in Shelby County’s NBIS database. This report indicates that a larger range of weighted data will produce a more acceptable frequency distribution in the initial probability matrix. Therefore, additional research in the development of the initial transition matrix is recommended.

P sub

.8889

0

0

0

0

0

0

0

.1111

.7143

0

0

0

0

0

0

0

.2857

.8421

0

0

0

0

0

0

0

.1579

.9070

0

0

0

0

0

0

0

.0930

.92

0

0

0

0

0

0

0

.08

.9999

0

0

0

0

0

0

0

.0001

.8

0

0

0

0

0

0

0

.2

1

q 0 1 0 0 0 0 0 0 0( )=

n 20=

q 20sub q 0 P subn.

q 20sub 0.095 0.06 0.2 0.342 0.208 0.095 2.195 10 5. 1.272 10 5.=

Figure 6-2. Substructure Probability Matrix and 20-year Projection

By varying the position of the unity within the initial condition rating matrix q0, a transition probability for structures with initial ratings other than 9 can be developed. For instance, a bridge

60

with a substructure rating of 6 would yield a 20-year projected probability matrix q20sub as shown in Figure 6-3.

q 0. 0 0 0 1 0 0 0 0( )

n 20=

q 20sub q 0. P subn.

q 20sub 0 0 0 0.142 0.334 0.523 1.881 10 4. 2.345 10 4.=

Figure 6-3. 20-year Projection of Existing Condition Rating of 6

It is then evident that this particular structures 99th percentile occurs between a condition rating of 6 and a condition rating of 4. Therefore, if the bridge manager chooses a bandwidth for replacement exceeding a 99th percentile at 20 years, or a condition rating of 3 or less, then this bridge will not require replacement. In conclusion, the bridge manager has a powerful planning tool on his hands if he can adequately define the initial Markov transition probability matrices for his bridge network.

Prediction of Future Sufficiency Ratings

Several of the individual components of the composite sufficiency rating are directly affected by the passage of time. These include, but are not limited to, the condition ratings and ADT. Therefore, it is necessary for the bridge manager to account for these direct variances in order to adequately forecast future sufficiency ratings.

ADT is most commonly projected using the following future value equation. The yearly percentage increase of traffic is normally taken as 3.5%. This rate has been found somewhat conservative in certain areas of Shelby County but is generally accepted by the Alabama Department of Transportation as a planning tool.

Before this study, Shelby County did not attempt to project condition ratings. However, as demonstrated previously, the condition of a structure does deteriorate over time and can be predicted by applying a Markov transition matrix. For the Shelby County study group, the future ADT’s and condition ratings are shown in Table 6-1. Note that the resulting future sufficiency ratings are also given. These projected sufficiency ratings reflect variances of ADT and structural condition ratings only.

The projected condition ratings are aggregate averages of the probabilities of a given condition based on the probability matrix q20. By multiplying the probability of a given condition occurring and summing the various resulting factors, an aggregate condition rating for the given projection period and condition is calculated.

61

Table 6-1. Projected ADT’s, Condition Ratings, and Sufficiency Ratings for the Shelby County Group Study

Structure Number Projected ADT Deck20 Super20 Sub20 Channel20 Sufficiency Rating20

013-59-634Q 2388 3.00 3.00 2.36 4.10 22.4

093-59-581Q 1791 3.00 3.00 4.19 4.26 23.0

334-59-595Q 199 3.03 3.18 4.00 4.10 28.9

446-59-601Q 398 3.14 3.18 4.19 4.00 37.1

020-59-538Q 497 3.03 3.18 4.00 4.10 49.9

034-59-544Q 696 3.00 3.07 2.36 4.00 45.3

103-59-584Q 298 3.50 3.40 4.62 4.44 39.3

086-59-578Q 700 3.03 3.07 4.00 4.44 47.1

078-59-611Q 1592 3.03 3.18 4.00 4.10 46.9

017-59-536Q 2189 3.50 3.40 4.62 4.44 50.3

107-59-587Q 728 3.00 3.00 2.36 4.26 46.5

103-59-585Q 995 3.03 3.18 2.36 4.44 46.8

086-59-576Q 700 3.03 3.18 4.19 4.44 47.4

343-59-598Q 199 3.14 3.18 4.19 4.26 55.3

000-59-501Q 398 3.14 3.18 4.19 4.10 49.2

010-59-526Q 4477 4.46 4.49 4.99 4.44 53.3

491-59-606Q 796 3.00 3.07 2.36 4.26 57.6

068-59-565Q 6168 3.14 3.18 4.19 4.26 47.3

077-59-569Q 199 8.00 8.00 5.23 4.68 82.6

446-59-602Q 398 8.07 8.01 6.21 4.26 72.1

62

Section 7 Recommended Applications of the Local Roads BRPD

Recommendations for Use

The BRPD Inspection and Filing System

This report recommends that county bridge inspectors initialize and maintain NBIS-type files to establish a county LT20 bridge network. Subject counties currently maintaining inspection files of these structures have been able to successfully prioritize and upgrade structures within this classification. Furthermore, eliminating or minimizing the imprecision of the LT20 system has significantly reduced potential exposure to liability within the subject counties.

Effectiveness of Prioritization Algorithm

The sufficiency rating has long been the standard indicator of a bridge’s eligibility for replacement. Using the available simplified inspection data, a supporting composite sufficiency rating has been developed for an LT20 bridge network. This sufficiency rating appears to adequately model the remaining sufficiency in existing LT20 bridges. Therefore, the prioritization algorithm in this report is effective in modeling the replacement priority of county LT20 bridges.

The Initial Markov Matrix

This report indicates that a more regionally based model might be constructed before the initial Markov matrix is applied to counties not in close proximity to the model county used in this report. Although similarities of construction materials, maintenance, ADT growth, overloading patterns, and funding seem to exist within regions of the state, great differences in these factors has been found to occur between regions. Therefore, more research is indicated to develop an initial regional Markov Matrix based on regional boundaries to be determined.

An initial study of Shelby County LT20 data shows that the existing population is too small and the data set is too compressed over time to allow for the development of a useable transition matrix. Therefore, the decision to develop a parallel transition matrix based on the NBIS data set for Shelby County was conducted. Of the modeled conditions, the substructure matrix shows that the data can produce a probability model. However, it is recommended that a more regional matrix be developed prior to applying these principles to other counties.

63

Appropriate Cost Models

The cost models contained in this report represent appropriate models of replacement alternatives as of the date of this report for counties similar in size, topography, and locale to Shelby County, Alabama. It is up to the individual user to verify that these models apply to his or her area of application and his time period. These models can also vary due to determinable factors such as haul distance, expertise of work crews, equipment used, and availability of materials, and require adjustment for the applicable factors.

Use of the Output

In the past, similar output has been used to prioritize Shelby County’s NBIS and LT20 bridge replacement programs. Initial five-year figures indicate that Shelby County is on track to eliminate all load-posted structures within the next five years. Therefore, it stands to reason that the data developed through the application of the inspection and prioritization techniques in this study can be effectively used to characterize and fund a successful bridge replacement program.

Recommendations for Further Development of the Local Roads BRPD

As previously suggested within this report, additional research is necessary to develop a more general application of these findings to other LT20 bridge networks. The Shelby County bridge prioritization model has been found to be very successful in setting goals for bridge replacement that are manageable and achievable within the County. However, a broader scope of statewide prioritization or a county-by-county prioritization requires use of regional data to minimize the impact of inherent differences in past bridge design and construction policies. Therefore, additional research into regionalizing the initial Markov transition matrix is advisable.

Parallel research into innovative construction materials indicates that the bridge construction data in this report may quickly become outdated. Therefore, as newer techniques and designs are proven in the field of bridge replacement, these new ideas may be incorporated into the bridge replacement cost model presented in this report.

Finally, as requested by the Counties that participated in the focus group study, a simple format database must be developed and tested prior to the statewide implementation of this report. This database construction and beta testing will require a substantial amount of research and programming. Therefore, this report serves as proof of concept and demonstration of need for focus on the growing problem of the particular subclass of bridges known as LT20’s.

64

Section 8 References

AASHTO (American Association of State Highway and Transportation Officials). A Policy on

Geometric Design of Highways and Streets. AASHTO Task Force on Geometric Design. Washington, D.C. 1990.

AASHTO (American Association of State Highway and Transportation Officials). Guidelines for Bridge Management Systems.

AASHTO (American Association of State Highway and Transportation Officials). Manual for Condition Evaluation of Bridges, Second Edition. AASHTO Highway Subcommittee on Bridges and Structures. Washington, D.C. 2000.

ACCA (Association of County Commissions of Alabama). The Crisis Continues. Needs Assessment for Alabama Counties, ACCA Report to the Alabama Legislature, February 1999.

AISI (American Iron and Steel Institute). Short Span Steel Bridges, AISIBEAM Software, Version 2.0. Publication No. TSC-98B. Washington, D.C. 1998.

ALDOT (Alabama Department of Transportation). Alabama Bridge Inspection Manual. Maintenance Bureau. Montgomery, Alabama. 1997.

ALDOT (Alabama Department of Transportation). County Road Design Policy. County Transportation Bureau, Revision 6. 1997.

Archilla, Adrian Ricardo. A Discussion of “Method for Estimating Transition Probability in Bridge Deterioration Models”. Journal of Infrastructure Systems. American Society of Civil Engineers, Volume 5, No. 2. 1999.

Atkins, J. B. Magnitude and Frequency of Floods in Alabama. Water-Resources Investigations Report 95-4199. United States Department of the Interior, Geological Survey. Tuscaloosa, Alabama. 1996.

Beyer, William H. CRC Standard Mathematical Tables. 26th Edition, CRC Press, Inc. Boca Raton, Florida. 1983.

Cesare, Mark A., Carlos Santamarina, Carl Turkstra, and Erik H. Vanmarcke. “Modeling Bridge Deterioration with Markov Chains”. Journal of Transportation Engineering, Vol. 118, No. 6. American Society of Civil Engineers. 1992.

DeStefano, Paul D., and Dimitri A Grivas. “Method for Estimating Transition Probability in Bridge Deterioration Models”. Journal of Infrastructure Systems. American Society of Civil Engineers, Volume 4, No. 2. June 1998.

FHWA (Federal Highway Administration). Culvert Inspection Manual. Washington D.C., United States Department of Transportation, 1986. (FHWA-IP-86-2)

FHWA (Federal Highway Administration). Evaluation Procedure for Corrugated Metal Structures (In-Situ). Washington D.C., United States Department of Transportation, 1989. (FHWA/OH-89-005)

65

Gere, James M., and William Weaver, Jr. Matrix Algebra for Engineers. Brooks/Cole Publishing Company, Monterey, California. 1983. Second Edition.

Hearn, George, Dan M. Frangopol, and Milan Chakravorty. “Calibration and Application of Deterioration Models for Highway Bridges”. Proceedings from the Fourth International Bridge Engineering Conference. Transportation Research Board. 1995.

Hjelmfelt, Allen T., Jr., and John J. Cassidy. Hydrology for Engineers and Planners. Iowa State University Press. Ames, Iowa. 1975.

Kaminsky, “Preliminary Cost Estimating for Highway Construction Projects”. 1986. Kivisto, Paul M., and Donald J. Fleming. “Managing Minnesota’s Bridges”. Fourth Annual

Bridge Engineering Conference. Volume 1, Transportation Research Board & National Research Council. National Academy Press. Washington, D.C. 1995.

Mizrahi, Abe, and Michael Sullivan. Finite Mathematics: An Applied Approach. pp. 451 – 478. John Wiley & Sons, Inc., New York, NY. Seventh Edition.

Ritter, Michael A. Timber Bridges: Design, Construction, Inspection, and Maintenance. United States Department of Agriculture, Forest Service, EM 7700-8. Washington, D.C. 1992.

Tuma, Jan J. Handbook of Numerical Calculations in Engineering. McGraw-Hill Publishing Company. New York, N.Y. 1989.

Sherman Industries. Products Selection Guide. Sherman Industries, Birmingham, Alabama. 1990.

Sherman International, Inc. Concrete Pipe Products Selection Guide. Sherman Concrete Pipe, Inc. Birmingham, Alabama. 1998.

Transportation Research Board Special Report 214. Designing Safer Roads: Practices for Resurfacing, Restoration, and Rehabilitation. National Research Council, Washington, D.C. 1987.

Yi, Jiang, Mitsuru Saito, and Kumares C. Sinha. “Bridge Performance Prediction Model Using the Markov Chain”. Transportation Research Record, Vol. 1180. Transportation Research Board. 1988.

Yi, Jiang and Kumares C. Sinha. “Bridge Service Life Prediction Model Using the Markov Chain”. Transportation Research Record, Vol. 1223. Transportation Research Board. 1989.

Yi, Jiang and Kumares C. Sinha. “Dynamic Optimization Model for Bridge Management Systems”. Transportation Research Record, Vol. 1211. Transportation Research Board. 1989.

66

Appendix A The BRPD Focus Group Survey

67

March 6, 2003

«Prefix» «First_Name» «Last_Name», PE «Title» «Organization» «Address1» «Address2» «City», «State» «Zip_Code»«Prefix»

Dear «Prefix» «Last_Name»:

Last year, I was given the opportunity to present Shelby County’s LT20 Bridge Prioritization Program to the Alabama County Engineers Association in Gulf Shores. Also, I recently presented a compilation of research to date on a related project that is funded by the University Transportation Center for Alabama at the Southeast Local Roads Conference in Point Clear, Alabama. As a result of continuing interest in this program, the University of Alabama in Birmingham and the University Transportation Centers of Alabama has funded additional research into this vital aspect of transportation management.

Part of the research requires interaction and input from the potential users group. In light of this requirement, your county or municipality has been selected to participate in a focus group survey. I have done my best to make the enclosed survey as concise and painless as possible. I ask that you do your best to adequately answer all the questions and to return the survey as soon as you can. I have supplied a self-addressed stamped envelope for your use.

The nature of this research also requires that I beta test the resulting database engine. Please indicate if you would be interested in becoming a beta tester. Feel free to call me at (205)669-3880 if you require more information.

Thank you in advance for your participation in the development of the Local Roads Bridge Prioritization Database.

Sincerely yours,

Thomas C. Grimes, PE

Cc: Dr. Jim Davidson, UAB

68

UTCA Local Roads Bridge Prioritization Database

Focus Group Survey

March 6, 2003

Participant Information

Name: _______________________________________

Organization: _________________________________

Address: _____________________________________

_____________________________________

Phone: ____________________

Fax: _____________________

Email: ___________________

69

UTCA Local Roads Bridge Prioritization Database Focal Group Survey Page 1 Please answer all questions as completely as possible. You may enclose additional sheets as required. An “LT20” is defined for the purposes of this survey as “any bridge or culvert having a total span less than 20 feet in length along the centerline of the roadway and having more than 40 square feet of cross-sectional opening in the plane of the roadway centerline.” These structures are officially designated as “non-NBIS structures” by FHWA and ALDOT.

How many LT20’s does «Organization» currently maintain in service?

______________________________________________________________

Of the identified LT20’s, how many are currently under routine inspection cycles?

_______________________________________________________________

Of the identified LT20’s, how many are currently load rated?

______________________________________________________________

Of the identified LT20’s, how many are currently load posted?

______________________________________________________________

National Bridge Inspection standards require states, counties, and municipalities to maintain inspection files for bridges 20 feet or greater in length. Currently, no agency is required to maintain comparable inspection files for LT20’s. Does «Organization» currently maintain a separate filing system for these non-NBIS structures?

Yes __________ No ____________

If you answered “yes”, then briefly explain your current filing system’s content and structure.

________________________________________________________________

________________________________________________________________

70

UTCA Local Roads Bridge Prioritization Database Focal Group Survey Page 2 ________________________________________________________________

________________________________________________________________

________________________________________________________________

The need to prioritize and replace LT20’s has been established through ACCA’s needs assessment for Alabama counties entitled “The Crisis Continues” (released February 11, 1999). This assessment was based on original data collected from 44 reporting counties within Alabama and submitted to the ALDOT County Transportation Bureau in response to Memorandum 94-07.

Did «Organization» submit data? Yes ________ No __________

Do you maintain a current file of this data? Yes ________ No __________

If yes, please indicate the format and content of this data.

______________________________________________________________

______________________________________________________________

______________________________________________________________

Briefly outline ongoing inspection and maintenance activities that relate to «Organization»’s current LT20 replacement program.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

71

UTCA Local Roads Bridge Prioritization Database Focal Group Survey Page 3

A need for a concise system to catalogue, prioritize and replace LT20’s and other bridges has been expressed by many counties and municipalities. However, past discussions have not specifically requested input from potential users.

Please list activities, guidelines, techniques, or technologies that you would find helpful in establishing or improving a bridge prioritization program in «Organization».

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

If a system containing some or all of the above characteristics was made available to you, how willing would you be to put it to use? Please explain why or why not.

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

Would «Organization» be willing to serve as a beta tester for the Local Roads Bridge Replacement Prioritization Database? (Beta testers receive free prototype copies of the BRPD and pro bono consultation with respect to its use)

Yes __________ No ____________

Maybe, but I require more information on ______________________________

72

Appendix B BRPD Focus Group Survey Results

73

UTCA Local Roads Bridge Prioritization Database Focus Group Survey Results

May 25, 2000

UTCA Local Roads Bridge Prioritization Database

Name: Randy Tindall, P. E. Organization: Coffee County Highway Department New Brockton, Alabama 36351 Address: P. O. Box 428 Phone: (334) 894-6112 Fax: (334)-894-6317 Email: coffee19@entercomp.com Focal Group Survey—Coffee County Response

Please answer all questions as completely as possible. You may enclose additional sheets as required. An “LT20” is defined for the purposes of this survey as “any bridge or culvert having a total span less than 20 feet in length along the centerline of the roadway and having more than 40 square feet of cross-sectional opening in the plane of the roadway centerline.” These structures are officially designated as “non-NBIS structures” by FHWA and ALDOT.

1. How many LT20’s does Coffee County currently maintain in service? 34 Of the identified LT20’s, how many are currently under routine inspection cycles?

None Of the identified LT20’s, how many are currently load rated? None Of the identified LT20’s, how many are currently load posted? None

2. National Bridge Inspection standards require states, counties, and municipalities to maintain inspection files for bridges 20 feet or greater in length. Currently, no agency is required to maintain comparable inspection files for LT20’s. Does Coffee County currently maintain a separate filing system for these non-NBIS structures?

Yes No XXX

If you answered “yes”, then briefly explain your current filing system’s content and structure.

[Not answered.]

74

3. The need to prioritize and replace LT20’s has been established through ACCA’s needs assessment for Alabama counties entitled “The Crisis Continues” (released February 11, 1999). This assessment was based on original data collected from 44 reporting counties within Alabama and submitted to the ALDOT County Transportation Bureau in response to Memorandum 94-07.

Did Coffee County submit data? Yes XXX No

Do you maintain a current file of this data? Yes XXX No

If yes, please indicate the format and content of this data.

A map with the locations of LT20’s spotted.

4. Briefly outline ongoing inspection and maintenance activities that relate to Coffee County’s current LT20 replacement program.

All paved roads are inspected and graded once a year. The LT20 structures are inspected as the roadway is inspected at that time.

5. A need for a concise system to catalogue, prioritize and replace LT20’s and other bridges has been expressed by many counties and municipalities. However, past discussions have not specifically requested input from potential users.

Please list activities, guidelines, techniques, or technologies that you would find helpful in establishing or improving a bridge prioritization program in Coffee County.

A database which is user friendly and easy to maintain in the County Engineer’s office.

If a system containing some or all of the above characteristics was made available to you, how willing would you be to put it to use? Please explain why or why not.

It would depend on how complex and time consuming the system would be. Right now it is all we can do to stay in compliance with ABIMS (GT20’s).

Would Coffee County be willing to serve as a beta tester for the Local Roads Bridge Replacement Prioritization Database? (Beta testers receive free prototype copies of the BRPD and pro bono consultation with respect to its use)

Yes No XXX

Maybe, but I require more information on [No Response].

75

UTCA Local Roads Bridge Prioritization Database Name: Neal Hall, P. E., Lee County Engineer Organization: Lee County Highway Department Address: P. O. Box 1007 Opelika, Alabama 36803 Phone: (334) 745-9792 Fax: (334) 745-9794 Email: [No Response] Focal Group Survey—Lee County Response

Please answer all questions as completely as possible. You may enclose additional sheets as required. An “LT20” is defined for the purposes of this survey as “any bridge or culvert having a total span less than 20 feet in length along the centerline of the roadway and having more than 40 square feet of cross-sectional opening in the plane of the roadway centerline.” These structures are officially designated as “non-NBIS structures” by FHWA and ALDOT.

1. How many LT20’s does Lee County currently maintain in service? 21 Of the identified LT20’s, how many are currently under routine inspection cycles?

None Of the identified LT20’s, how many are currently load rated? None Of the identified LT20’s, how many are currently load posted? None

2. National Bridge Inspection standards require states, counties, and municipalities to maintain inspection files for bridges 20 feet or greater in length. Currently, no agency is required to maintain comparable inspection files for LT20’s. Does Lee County currently maintain a separate filing system for these non-NBIS structures?

Yes No XXX

If you answered “yes”, then briefly explain your current filing system’s content and structure.

[No Response.]

3. The need to prioritize and replace LT20’s has been established through ACCA’s needs assessment for Alabama counties entitled “The Crisis Continues” (released February 11, 1999). This assessment was based on original data collected from 44 reporting counties within Alabama and submitted to the ALDOT County Transportation Bureau in response to Memorandum 94-07.

Did Lee County submit data? Yes XXX No

Do you maintain a current file of this data? Yes XXX No

76

If yes, please indicate the format and content of this data.

A location map and any work orders completed on these structures.

4. Briefly outline ongoing inspection and maintenance activities that relate to Lee County’s current LT20 replacement program.

LT20’s are inspected when a complaint is phoned in or a Road Foreman reports a suspected problem. If a problem is verified by inspection the problem is corrected as quickly as possible.

5. A need for a concise system to catalogue, prioritize and replace LT20’s and other bridges

has been expressed by many counties and municipalities. However, past discussions have not specifically requested input from potential users.

Please list activities, guidelines, techniques, or technologies that you would find helpful in establishing or improving a bridge prioritization program in Lee County.

We are satisfied with our current system on the LT20’s and find the ALDOT ABIMS program sufficient in monitoring all our other structures.

If a system containing some or all of the above characteristics was made available to you, how willing would you be to put it to use? Please explain why or why not.

We at this time would not be interested in using a new system since our current system seems to be working well for our needs.

Would Lee County be willing to serve as a beta tester for the Local Roads Bridge Replacement Prioritization Database? (Beta testers receive free prototype copies of the BRPD and pro bono consultation with respect to its use)

Yes No XXX

Maybe, but I require more information on [No Response].

77

UTCA Local Roads Bridge Prioritization Database Name: Mike Shaw Organization: Marion County Highway Department Address: P. O. Box 1717 Hamilton, Alabama 35570 Phone: (205) 921-2115 Fax: (205)-921-7815 Email: marioneg@sonet.net

Focal Group Survey—Marion County Response

Please answer all questions as completely as possible. You may enclose additional sheets as required. An “LT20” is defined for the purposes of this survey as “any bridge or culvert having a total span less than 20 feet in length along the centerline of the roadway and having more than 40 square feet of cross-sectional opening in the plane of the roadway centerline.” These structures are officially designated as “non-NBIS structures” by FHWA and ALDOT.

1. How many LT20’s does Marion County currently maintain in service? ∼21 Of the identified LT20’s, how many are currently under routine inspection cycles?

None Of the identified LT20’s, how many are currently load rated? None Of the identified LT20’s, how many are currently load posted? None

2. National Bridge Inspection standards require states, counties, and municipalities to maintain inspection files for bridges 20 feet or greater in length. Currently, no agency is required to maintain comparable inspection files for LT20’s. Does Marion County currently maintain a separate filing system for these non-NBIS structures?

Yes No XXX

If you answered “yes”, then briefly explain your current filing system’s content and structure.

[No Response]

3. The need to prioritize and replace LT20’s has been established through ACCA’s needs assessment for Alabama counties entitled “The Crisis Continues” (released February 11, 1999). This assessment was based on original data collected from 44 reporting counties within Alabama and submitted to the ALDOT County Transportation Bureau in response to Memorandum 94-07.

Did Marion County submit data? Yes XXX No

Do you maintain a current file of this data? Yes No XXX

78

If yes, please indicate the format and content of this data.

[No Response]

4. Briefly outline ongoing inspection and maintenance activities that relate to Marion County’s current LT20 replacement program.

There are no routine inspections being performed. Inspections are performed per request or problems noticed.

5. A need for a concise system to catalogue, prioritize and replace LT20’s and other bridges has been expressed by many counties and municipalities. However, past discussions have not specifically requested input from potential users.

Please list activities, guidelines, techniques, or technologies that you would find helpful in establishing or improving a bridge prioritization program in Marion County.

A system similar to the bridge inspection program, but much less complex.

If a system containing some or all of the above characteristics was made available to you, how willing would you be to put it to use? Please explain why or why not.

Yes, to minimize liability and prevent problems.

Would Coffee County be willing to serve as a beta tester for the Local Roads Bridge Replacement Prioritization Database? (Beta testers receive free prototype copies of the BRPD and pro bono consultation with respect to its use)

Yes No

Maybe, but I require more information on what is required.

79

UTCA Local Roads Bridge Prioritization Database

Name: Anthony Garner Organization: Franklin County Highway Department Address: P. O. Box 717 Russellville, Alabama 35653 Phone: (256) 332-8434 Fax: (256) 332-8430 Email: [No Response] Focal Group Survey—Franklin County Response

Please answer all questions as completely as possible. You may enclose additional sheets as required. An “LT20” is defined for the purposes of this survey as “any bridge or culvert having a total span less than 20 feet in length along the centerline of the roadway and having more than 40 square feet of cross-sectional opening in the plane of the roadway centerline.” These structures are officially designated as “non-NBIS structures” by FHWA and ALDOT.

1. How many LT20’s does Franklin County currently maintain in service? ∼70 Of the identified LT20’s, how many are currently under routine inspection cycles?

None Of the identified LT20’s, how many are currently load rated? None Of the identified LT20’s, how many are currently load posted? None

2. National Bridge Inspection standards require states, counties, and municipalities to maintain inspection files for bridges 20 feet or greater in length. Currently, no agency is required to maintain comparable inspection files for LT20’s. Does Franklin County currently maintain a separate filing system for these non-NBIS structures?

Yes No XXX

If you answered “yes”, then briefly explain your current filing system’s content and structure.

[No Response.]

3. The need to prioritize and replace LT20’s has been established through ACCA’s needs assessment for Alabama counties entitled “The Crisis Continues” (released February 11, 1999). This assessment was based on original data collected from 44 reporting counties within Alabama and submitted to the ALDOT County Transportation Bureau in response to Memorandum 94-07.

Did Franklin County submit data? Yes XXX No

Do you maintain a current file of this data? Yes XXX No

80

If yes, please indicate the format and content of this data.

Have a map with these structures located. Data includes location, type structure, length & width. (Information taken 1996.)

4. Briefly outline ongoing inspection and maintenance activities that relate to Franklin County’s current LT20 replacement program.

Inspect on a need bases and replace these structures the same way. In the past we have replaced some of these bridges with metal pipe.

5. A need for a concise system to catalogue, prioritize and replace LT20’s and other bridges has been expressed by many counties and municipalities. However, past discussions have not specifically requested input from potential users.

Please list activities, guidelines, techniques, or technologies that you would find helpful in establishing or improving a bridge prioritization program in Franklin County.

Guidelines—Have a grading system to evaluate the structure’s condition similar to ALDOT’s annual maintenance review form only pertaining to LT20’s.

Prioritize—give higher priority to structures due to higher traffic counts, meet clear zone requirements.

If a system containing some or all of the above characteristics was made available to you, how willing would you be to put it to use? Please explain why or why not.

Yes. Unless the system became too bulky and labor intensive. Short of manpower.

Would Franklin County be willing to serve as a beta tester for the Local Roads Bridge Replacement Prioritization Database? (Beta testers receive free prototype copies of the BRPD and pro bono consultation with respect to its use)

Yes No

Maybe, but I require more information on [Yes].

81

UTCA Local Roads Bridge Prioritization Database

Name: Kenneth R. Cole, P. E. Organization: Shelby County Highway Department Address: P. O. Box 467 Columbiana, Alabama 35051 Phone: (205) 669-3880 Fax: (334) 669-3882 Email: rcole@shelbycountyalabama.net Focal Group Survey—Shelby County Response

Please answer all questions as completely as possible. You may enclose additional sheets as required. An “LT20” is defined for the purposes of this survey as “any bridge or culvert having a total span less than 20 feet in length along the centerline of the roadway and having more than 40 square feet of cross-sectional opening in the plane of the roadway centerline.” These structures are officially designated as “non-NBIS structures” by FHWA and ALDOT.

1. How many LT20’s does Shelby County currently maintain in service? 87 Of the identified LT20’s, how many are currently under routine inspection cycles?

All are on a four-year routine cycle, and posted structures are inspected yearly. Of the identified LT20’s, how many are currently load rated? 87 Of the identified LT20’s, how many are currently load posted? 1

2. National Bridge Inspection standards require states, counties, and municipalities to maintain inspection files for bridges 20 feet or greater in length. Currently, no agency is required to maintain comparable inspection files for LT20’s. Does Shelby County currently maintain a separate filing system for these non-NBIS structures.

Yes XXX No

If you answered “yes”, then briefly explain your current filing system’s content and structure.

Bridge inspectors are required to perform initial inspections on all new installations, and to complete routine and interim inspections similar to the NBIS requirements. A separate file is required for all structures fitting the LT20 category, and all design, inspection, rating, posting, repair, replacement, and incident data is maintained in perpetuity for each structure. A unique numbering system similar to the old NBIS Structure Number is maintained with location maps to track the LT20 network.

3. The need to prioritize and replace LT20’s has been established through ACCA’s needs assessment for Alabama counties entitled “The Crisis Continues” (released February 11, 1999). This assessment was based on original data collected from 44 reporting counties

82

within Alabama and submitted to the ALDOT County Transportation Bureau in response to Memorandum 94-07.

Did Shelby County submit data? Yes XXX No

Do you maintain a current file of this data? Yes XXX No

If yes, please indicate the format and content of this data.

A location map and individual files are maintained with historical data similar to the NBIS filing requirements.

4. Briefly outline ongoing inspection and maintenance activities that relate to Shelby County’s current LT20 replacement program.

All structures are inspected using NBIS condition rating standards on a 4-year routine frequency. Interim inspections are conducted yearly or at greater frequencies as recommended in the FHWA Bridge Inspection Guidelines. Currently, Shelby County is conducting an LT20 Bridge Replacement program that will establish a network of LT20’s equal to or less than 10 years old. This program is expected to be complete in 5 years. To date, all load posted LT20’s have been replaced with one exception.

5. A need for a concise system to catalogue, prioritize and replace LT20’s and other bridges has been expressed by many counties and municipalities. However, past discussions have not specifically requested input from potential users.

Please list activities, guidelines, techniques, or technologies that you would find helpful in establishing or improving a bridge prioritization program in Shelby County.

A user-friendly database management program that will be stand-alone, voluntary, and maintained only at the County level.

If a system containing some or all of the above characteristics was made available to you, how willing would you be to put it to use? Please explain why or why not.

Shelby County already maintains a database. Additional improvements to the existing database are sought, including the ability to incorporate the date into a GIS environment.

Would Shelby County be willing to serve as a beta tester for the Local Roads Bridge Replacement Prioritization Database? (Beta testers receive free prototype copies of the BRPD and pro bono consultation with respect to its use)

Yes XXX No XXX

Maybe, but I require more information on [No Response].

83

Appendix C BRPD Inspection Data Sheet

84

LT-20 Bridge Inspection Report Date:

Structure Number Node 1 Node 2 Distance from Node 1 Link

Route Latitude Longitude Waterway Load Posting

Approach Road Measurement Design Information MeasurementLeft Shoulder Width Drainage AreaRoadway Width Q25

Right Shoulder Width Q100

Total Width ADTRoadway Classification Projected ADT

Description of LT-20Material Length along Roadway CL

Skew Opening HeightLength along Streambed Opening Area

ConditionDeck Rating Superstructure RatingWearing Surface Deck SlabDeck-Structural Stringers or Beams Railing PaintUtilities Rivets, Bolts or WeldsCollision Damage Collision Damage

Deflection Under LoadAlignment of MembersVibration Under Load

Overall Rating Overall Rating

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps Channel ScourWings Embankment ErosionBackwall DriftFooting / Drilled Shaft SiltPiles / Columns VegetationErosion / Scour Channel Migration Settlement Pier Protection Collision Damage Rip RapPiers or Bents Adequacy of Opening Caps Alignment with StructureColumnsFooting / Drilled ShaftPiles (PC,S,T)ScourSettlementBracingDebris on SeatsCollision Damage

Overall Rating Overall Rating

accfscfs

tons

deg.ftftft

ftftftft

ft

85

LT-20 Bridge Inspection Report (Back)

Photograph Notes

Upstream Cross Section Remarks:

Photo ID -

Downstream Cross Section Remarks:

Photo ID -

Roadway Surface Remarks:

Photo ID -

Superstructure Remarks:

Photo ID -

Substructure Remarks:

Photo ID -

86

Appendix D Shelby County BRPD Group Study

87

LT-20 Bridge Inspection Report Date: 10/24/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link068-59-565Q 342 343 5067

Route Latitude Longitude Waterway Load Posting68 PEAVINE CREEK 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 9 Drainage Area 231Roadway Width 20 Q25 317Right Shoulder Width 3 Q100 433Total Width 32 ADT 3100Roadway Classification 3 Projected ADT 6168

Description of LT-20Material TIMBER Length along Roadway CL 10Skew 0 Opening Height 5Length along Streambed 27 Opening Area 50

ConditionDeck Rating Superstructure RatingWearing Surface 7 Deck Slab NDeck-Structural 5 Stringers or Beams 5Railing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 6Alignment of Members 7Vibration Under Load 6

Overall Rating 5 Overall Rating 5

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 4 Channel Scour 6Wings 4 Embankment Erosion 6Backwall 5 Drift 6Footing / Drilled Shaft 6 Silt 8Piles / Columns 5 Vegetation 8Erosion / Scour 6 Channel Migration NSettlement 6 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 7Caps N Alignment with Structure 8Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 5 Overall Rating 6

accfscfs

tons

deg.ftftft

ftftftft

ft

88

LT-20 Bridge Inspection Report Date: 10/24/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link020-59-538Q 31 22 970 1013

Route Latitude Longitude Waterway Load Posting20 UT BUXAHATCHEE CREEK 12

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 2 Drainage Area 854Roadway Width 18 Q25 760Right Shoulder Width 3 Q100 1036Total Width 23 ADT 250Roadway Classification 2 Projected ADT 497

Description of LT-20Material TIMBER Length along Roadway CL 16Skew 30 Opening Height 5Length along Streambed 29 Opening Area 80

ConditionDeck Rating Superstructure RatingWearing Surface 4 Deck Slab NDeck-Structural 4 Stringers or Beams 5Railing 5 Paint NUtilities N Rivets, Bolts or Welds NCollision Damage N Collision Damage N

Deflection Under Load 3Alignment of Members 7Vibration Under Load 4

Overall Rating 4 Overall Rating 5

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 4 Channel Scour 5Wings 5 Embankment Erosion 5Backwall 4 Drift 7Footing / Drilled Shaft 5 Silt 7Piles / Columns 4 Vegetation 8Erosion / Scour 6 Channel Migration 5Settlement 4 Pier Protection NCollision Damage 7 Rip Rap 7Piers or Bents Adequacy of Opening 6Caps N Alignment with Structure 4Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 4 Overall Rating 5

accfscfs

tons

deg.ftftft

ftftftft

ft

89

LT-20 Bridge Inspection Report Date: 10/24/00

Structure Number Node 1 Node 2 Distance from Node 1 Link078-59-611Q 7159 131 1067

Route Latitude Longitude Waterway Load Posting78 UT LITTLE CREEK 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 2 Drainage Area 402Roadway Width 20 Q25 460Right Shoulder Width 3 Q100 627Total Width 25 ADT 800Roadway Classification 1 Projected ADT 1592

Description of LT-20Material TIMBER Length along Roadway CL 9Skew 0 Opening Height 11Length along Streambed 25 Opening Area 99

ConditionDeck Rating Superstructure RatingWearing Surface 8 Deck Slab NDeck-Structural 4 Stringers or Beams 5Railing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage N Collision Damage N

Deflection Under Load 6Alignment of Members 7Vibration Under Load 6

Overall Rating 4 Overall Rating 5

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 4 Channel Scour 5Wings 4 Embankment Erosion 5Backwall 4 Drift 6Footing / Drilled Shaft 5 Silt 6Piles / Columns 4 Vegetation 8Erosion / Scour 4 Channel Migration 6Settlement 5 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 6Caps N Alignment with Structure 7Columns NFooting / Drilled Shaft N

accfscfs

tons

deg.ftftft

ftftftft

ft

90

LT-20 Bridge Inspection Report Date: 10/24/00

Structure Number Node 1 Node 2 Distance from Node 1 Link093-59-581Q 7876 7879 1243

Route Latitude Longitude Waterway Load Posting93 UT HURRICANE CREEK 3

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 2 Drainage Area 995Roadway Width 21 Q25 842Right Shoulder Width 3 Q100 1148Total Width 26 ADT 900Roadway Classification 2 Projected ADT 1791

Description of LT-20Material TIMBER Length along Roadway CL 18Skew 0 Opening Height 10Length along Streambed 23 Opening Area 180

ConditionDeck Rating Superstructure RatingWearing Surface 5 Deck Slab NDeck-Structural 3 Stringers or Beams 3Railing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 4Alignment of Members 7Vibration Under Load 4

Overall Rating 3 Overall Rating 3

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 4 Channel Scour 6Wings 3 Embankment Erosion 6Backwall 4 Drift 7Footing / Drilled Shaft 5 Silt 7Piles / Columns 3 Vegetation 8Erosion / Scour 4 Channel Migration 5Settlement 4 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 7Caps N Alignment with Structure 4Columns NFooting / Drilled Shaft N

accfscfs

tons

deg.ftftft

ftftftft

ft

91

LT-20 Bridge Inspection Report Date: 10/24/00

Structure Number Node 1 Node 2 Distance from Node 1 Link107-59-587Q 10263 7478 1133

Route Latitude Longitude Waterway Load Posting107 UT SPRING CREEK 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 3 Drainage Area 172Roadway Width 18 Q25 160Right Shoulder Width 3 Q100 198Total Width 24 ADT 366Roadway Classification 2 Projected ADT 728

Description of LT-20Material TIMBER Length along Roadway CL 9Skew 0 Opening Height 5Length along Streambed 24 Opening Area 45

ConditionDeck Rating Superstructure RatingWearing Surface 4 Deck Slab 3Deck-Structural 3 Stringers or Beams NRailing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 3Alignment of Members 7Vibration Under Load 3

Overall Rating 3 Overall Rating 3

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 2 Channel Scour 6Wings 3 Embankment Erosion 7Backwall 3 Drift 7Footing / Drilled Shaft 4 Silt 7Piles / Columns 3 Vegetation 8Erosion / Scour 6 Channel Migration 8Settlement 4 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 6Caps N Alignment with Structure 8Columns NFooting / Drilled Shaft N

accfscfs

tons

deg.ftftft

ftftftft

ft

92

LT-20 Bridge Inspection Report Date: 10/24/00

Structure Number Node 1 Node 2 Distance from Node 1 Link334-59-595Q 8244 8243 1220

Route Latitude Longitude Waterway Load Posting334 PEAVINE CREEK 7

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 2 Drainage Area 1532Roadway Width 14 Q25 1123Right Shoulder Width 2 Q100 1530Total Width 18 ADT 100Roadway Classification 1 Projected ADT 198

Description of LT-20Material TIMBER Length along Roadway CL 18Skew 0 Opening Height 7Length along Streambed 15 Opening Area 126

ConditionDeck Rating Superstructure RatingWearing Surface 6 Deck Slab NDeck-Structural 4 Stringers or Beams 5Railing 6 Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 2Alignment of Members 7Vibration Under Load 3

Overall Rating 4 Overall Rating 5

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 5 Channel Scour 4Wings 3 Embankment Erosion 5Backwall 4 Drift 6Footing / Drilled Shaft 5 Silt 6Piles / Columns 5 Vegetation 8Erosion / Scour 4 Channel Migration 3Settlement 2 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 6Caps N Alignment with Structure 3Columns NFooting / Drilled Shaft N

accfscfs

tons

deg.ftftft

ftftftft

ft

93

LT-20 Bridge Inspection Report Date: 10/24/00

Structure Number Node 1 Node 2 Distance from Node 1 Link446-59-601Q 7296 7297 1145

Route Latitude Longitude Waterway Load Posting446 UT WEAVER CREEK 12

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 4 Drainage Area 670Roadway Width 12 Q25 646Right Shoulder Width 4 Q100 881Total Width 20 ADT 200Roadway Classification 1 Projected ADT 398

Description of LT-20Material TIMBER Length along Roadway CL 16Skew 0 Opening Height 4Length along Streambed 12 Opening Area 64

ConditionDeck Rating Superstructure RatingWearing Surface 3 Deck Slab NDeck-Structural 5 Stringers or Beams 5Railing 1 Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 4 Collision Damage N

Deflection Under Load 2Alignment of Members 7Vibration Under Load 3

Overall Rating 5 Overall Rating 5

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 5 Channel Scour 4Wings 5 Embankment Erosion 5Backwall 5 Drift 6Footing / Drilled Shaft 5 Silt 6Piles / Columns 5 Vegetation 8Erosion / Scour 3 Channel Migration 3Settlement 4 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 4Caps N Alignment with Structure 2Columns NFooting / Drilled Shaft N

accfscfs

tons

deg.ftftft

ftftftft

ft

94

LT-20 Bridge Inspection Report Date: 10/24/00

Structure Number Node 1 Node 2 Distance from Node 1 Link013-59-634Q 7874 7876 1114

Route Latitude Longitude Waterway Load Posting13 SHAW CREEK 3

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 4 Drainage Area 600Roadway Width 21 Q25 601Right Shoulder Width 5 Q100 819Total Width 30 ADT 1200Roadway Classification 3 Projected ADT 2388

Description of LT-20Material TIMBER Length along Roadway CL 16Skew 0 Opening Height 7Length along Streambed 28 Opening Area 112

ConditionDeck Rating Superstructure RatingWearing Surface 5 Deck Slab NDeck-Structural 3 Stringers or Beams 4Railing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage N

Deflection Under Load 2Alignment of Members 7Vibration Under Load 3

Overall Rating 3 Overall Rating 3

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 5 Channel Scour 5Wings 2 Embankment Erosion 5Backwall 3 Drift 6Footing / Drilled Shaft 5 Silt 6Piles / Columns 5 Vegetation 8Erosion / Scour 1 Channel Migration 8Settlement 3 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 7Caps N Alignment with Structure 6Columns NFooting / Drilled Shaft N

accfscfs

tons

deg.ftftft

ftftftft

ft

95

LT-20 Bridge Inspection Report Date: 10/24/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link010-59-526Q 378 36 1096

Route Latitude Longitude Waterway Load Posting10 UT KING CREEK 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 6 Drainage Area 309Roadway Width 20 Q25 386Right Shoulder Width 6 Q100 526Total Width 32 ADT 2250Roadway Classification 3 Projected ADT 4477

Description of LT-20Material CONCRETE Length along Roadway CL 10Skew 0 Opening Height 6Length along Streambed 32 Opening Area 60

ConditionDeck Rating Superstructure RatingWearing Surface 7 Deck Slab 7Deck-Structural 7 Stringers or Beams NRailing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage N

Deflection Under LoadAlignment of MembersVibration Under Load

Overall Rating 7 Overall Rating 7

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps N Channel Scour 7Wings 6 Embankment Erosion 6Backwall 7 Drift 6Footing / Drilled Shaft N Silt 6Piles / Columns N Vegetation 8Erosion / Scour N Channel Migration 8Settlement 7 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 7Caps N Alignment with Structure 7Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 7 Overall Rating 7

accfscfs

tons

deg.ftftft

ftftftft

ft

96

LT-20 Bridge Inspection Report Date: 10/24/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link017-59-536Q 7451 7458 1096

Route Latitude Longitude Waterway Load Posting17 UT KING CREEK 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 6 Drainage Area 426Roadway Width 20 Q25 478Right Shoulder Width 6 Q100 652Total Width 32 ADT 1100Roadway Classification 3 Projected ADT 2189

Description of LT-20Material CON./ MAS. Length along Roadway CL 12Skew 0 Opening Height 5Length along Streambed 23 Opening Area 60

ConditionDeck Rating Superstructure RatingWearing Surface 5 Deck Slab 6Deck-Structural 6 Stringers or Beams NRailing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 5 Collision Damage 7

Deflection Under Load 7Alignment of Members 7Vibration Under Load 7

Overall Rating 6 Overall Rating 6

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 6 Channel Scour 7Wings 6 Embankment Erosion 7Backwall 6 Drift 7Footing / Drilled Shaft 6 Silt 7Piles / Columns N Vegetation 8Erosion / Scour 7 Channel Migration 7Settlement 7 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 6Caps N Alignment with Structure 7Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 6 Overall Rating 7

accfscfs

tons

deg.ftftft

ftftftft

ft

97

LT-20 Bridge Inspection Report Date: 11/07/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link086-59-576Q 7084 7090 1020

Route Latitude Longitude Waterway Load Posting86 UT LONG BRANCH 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 4 Drainage Area 31Roadway Width 18 Q25 29Right Shoulder Width 4 Q100 36Total Width 26 ADT 352Roadway Classification 1 Projected ADT 700

Description of LT-20Material TIMBER Length along Roadway CL 8Skew 0 Opening Height 8Length along Streambed 26 Opening Area 64

ConditionDeck Rating Superstructure RatingWearing Surface 7 Deck Slab NDeck-Structural 4 Stringers or Beams 5Railing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 6Alignment of Members 7Vibration Under Load 6

Overall Rating 4 Overall Rating 5

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 5 Channel Scour 7Wings 4 Embankment Erosion 7Backwall 5 Drift 7Footing / Drilled Shaft 6 Silt 7Piles / Columns 5 Vegetation 8Erosion / Scour 7 Channel Migration 8Settlement 7 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 7Caps N Alignment with Structure 7Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 5 Overall Rating 7

accfscfs

tons

deg.ftftft

ftftftft

ft

98

LT-20 Bridge Inspection Report Date: 11/07/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link086-59-578Q 7084 7090 1020

Route Latitude Longitude Waterway Load Posting86 LT LONG BRANCH 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 4 Drainage Area 18Roadway Width 18 Q25 21Right Shoulder Width 3 Q100 26Total Width 25 ADT 352Roadway Classification 1 Projected ADT 700

Description of LT-20Material TIMBER Length along Roadway CL 8Skew 0 Opening Height 10Length along Streambed 24 Opening Area 80

ConditionDeck Rating Superstructure RatingWearing Surface 7 Deck Slab NDeck-Structural 4 Stringers or Beams 4Railing 2 Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 5Alignment of Members 7Vibration Under Load 5

Overall Rating 4 Overall Rating 4

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 4 Channel Scour 7Wings 3 Embankment Erosion 7Backwall 4 Drift 7Footing / Drilled Shaft 4 Silt 7Piles / Columns 4 Vegetation 8Erosion / Scour 7 Channel Migration 8Settlement 5 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 7Caps N Alignment with Structure 7Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 4 Overall Rating 7

accfscfs

tons

deg.ftftft

ftftftft

ft

99

LT-20 Bridge Inspection Report Date: 11/06/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link103-59-585Q 157 77 1162

Route Latitude Longitude Waterway Load Posting103 UT DRY BRANCH 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 1 Drainage Area 52Roadway Width 18 Q25 67Right Shoulder Width 1 Q100 81Total Width 20 ADT 500Roadway Classification 2 Projected ADT 995

Description of LT-20Material TIMBER Length along Roadway CL 9Skew 0 Opening Height 6Length along Streambed 21 Opening Area 54

ConditionDeck Rating Superstructure RatingWearing Surface 5 Deck Slab NDeck-Structural 4 Stringers or Beams 5Railing 5 Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 8Alignment of Members 7Vibration Under Load 4

Overall Rating 4 Overall Rating 5

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 2 Channel Scour 7Wings 3 Embankment Erosion 7Backwall 5 Drift 7Footing / Drilled Shaft 5 Silt 7Piles / Columns 5 Vegetation 8Erosion / Scour 7 Channel Migration 8Settlement 3 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 7Caps N Alignment with Structure 7Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 3 Overall Rating 7

accfscfs

tons

deg.ftftft

ftftftft

ft

100

LT-20 Bridge Inspection Report Date: 11/06/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link103-59-584Q 83 84 1162

Route Latitude Longitude Waterway Load Posting103 COOSA RIVER SLOUGH 12

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 4 Drainage Area 87Roadway Width 18 Q25 90Right Shoulder Width 4 Q100 110Total Width 26 ADT 150Roadway Classification 2 Projected ADT 298

Description of LT-20Material TIMBER Length along Roadway CL 17Skew 0 Opening Height 14Length along Streambed 25 Opening Area 238

ConditionDeck Rating Superstructure RatingWearing Surface 5 Deck Slab NDeck-Structural 6 Stringers or Beams 6Railing 6 Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 7Alignment of Members 7Vibration Under Load 6

Overall Rating 6 Overall Rating 6

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 6 Channel Scour 7Wings 6 Embankment Erosion 7Backwall 6 Drift 7Footing / Drilled Shaft N Silt 7Piles / Columns 7 Vegetation 8Erosion / Scour 7 Channel Migration 8Settlement 7 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 7Caps N Alignment with Structure 7Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 6 Overall Rating 7

accfscfs

tons

deg.ftftft

ftftftft

ft

101

LT-20 Bridge Inspection Report Date: 11/06/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link000-59-501Q 7557 7561 1224

Route Latitude Longitude Waterway Load PostingARABIAN ROAD UT BIG CREEK 15

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 4.5 Drainage Area 130Roadway Width 18 Q25 170Right Shoulder Width 1.5 Q100 223Total Width 23 ADT 200Roadway Classification 1 Projected ADT 398

Description of LT-20Material TIMBER Length along Roadway CL 13Skew 0 Opening Height 4Length along Streambed 27 Opening Area 52

ConditionDeck Rating Superstructure RatingWearing Surface 7 Deck Slab NDeck-Structural 5 Stringers or Beams 5Railing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 6Alignment of Members 7Vibration Under Load 5

Overall Rating 5 Overall Rating 5

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 5 Channel Scour 5Wings 5 Embankment Erosion 6Backwall 5 Drift 6Footing / Drilled Shaft 6 Silt 6Piles / Columns 5 Vegetation 8Erosion / Scour 5 Channel Migration 5Settlement 6 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 6Caps N Alignment with Structure 3Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 5 Overall Rating 5

accfscfs

tons

deg.ftftft

ftftftft

ft

102

LT-20 Bridge Inspection Report Date: 10/27/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link343-59-598Q 8202 N 1142

Route Latitude Longitude Waterway Load Posting343 UT WAXAHATHCEE CR. 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 3 Drainage Area 159Roadway Width 18 Q25 247Right Shoulder Width 2 Q100 338Total Width 23 ADT 100Roadway Classification 1 Projected ADT 198

Description of LT-20Material TIMBER Length along Roadway CL 13Skew 0 Opening Height 4Length along Streambed 23 Opening Area 52

ConditionDeck Rating Superstructure RatingWearing Surface 5 Deck Slab NDeck-Structural 5 Stringers or Beams 5Railing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage N

Deflection Under Load 5Alignment of Members 7Vibration Under Load 5

Overall Rating 5 Overall Rating 5

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 5 Channel Scour 6Wings 5 Embankment Erosion 6Backwall 5 Drift 6Footing / Drilled Shaft N Silt 6Piles / Columns 5 Vegetation 8Erosion / Scour 6 Channel Migration 4Settlement 6 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 5Caps N Alignment with Structure 1Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 5 Overall Rating 6

accfscfs

tons

deg.ftftft

ftftftft

ft

103

LT-20 Bridge Inspection Report Date: 10/25/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link034-59-544Q 165 7291 1220

Route Latitude Longitude Waterway Load Posting34 UT WOLF CREEK 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 3 Drainage Area 177Roadway Width 20 Q25 216Right Shoulder Width 2 Q100 284Total Width 25 ADT 350Roadway Classification 1 Projected ADT 696

Description of LT-20Material TIMBER Length along Roadway CL 16Skew 0 Opening Height 4Length along Streambed 24 Opening Area 64

ConditionDeck Rating Superstructure RatingWearing Surface 7 Deck Slab NDeck-Structural 3 Stringers or Beams 4Railing N Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage N

Deflection Under Load 3Alignment of Members 7Vibration Under Load 2

Overall Rating 3 Overall Rating 4

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 3 Channel Scour 4Wings 3 Embankment Erosion 5Backwall 3 Drift 6Footing / Drilled Shaft 5 Silt 6Piles / Columns 3 Vegetation 8Erosion / Scour 4 Channel Migration 3Settlement 3 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 6Caps N Alignment with Structure 1Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 3 Overall Rating 4

accfscfs

tons

deg.ftftft

ftftftft

ft

104

LT-20 Bridge Inspection Report Date: 10/25/2000

Structure Number Node 1 Node 2 Distance from Node 1 Link491-59-606Q 7812 7810 1363

Route Latitude Longitude Waterway Load Posting491 TUNNEL BRANCH 36

Approach Road Measurement Design Information MeasurementLeft Shoulder Width 3 Drainage Area 162Roadway Width 18 Q25 232Right Shoulder Width 3 Q100 301Total Width 24 ADT 400Roadway Classification 1 Projected ADT 796

Description of LT-20Material TIMBER Length along Roadway CL 12Skew 0 Opening Height 6.5Length along Streambed 29 Opening Area 78

ConditionDeck Rating Superstructure RatingWearing Surface 8 Deck Slab NDeck-Structural 3 Stringers or Beams 4Railing 2 Paint NUtilities N Rivets, Bolts or Welds NCollision Damage 7 Collision Damage 7

Deflection Under Load 4Alignment of Members 7Vibration Under Load 4

Overall Rating 3 Overall Rating 4

Substructure Rating Channel and Channel Protection RatingAbutmentsCaps 2 Channel Scour 6Wings 2 Embankment Erosion 6Backwall 4 Drift 6Footing / Drilled Shaft 5 Silt 6Piles / Columns 4 Vegetation 8Erosion / Scour 6 Channel Migration 8Settlement 5 Pier Protection NCollision Damage 7 Rip Rap NPiers or Bents Adequacy of Opening 6Caps N Alignment with Structure 7Columns NFooting / Drilled Shaft NPiles (PC,S,T) NScour NSettlement NBracing NDebris on Seats NCollision Damage N

Overall Rating 3 Overall Rating 6

accfscfs

tons

deg.ftftft

ftftftft

ft

105

Appendix E BRPD Bridge Replacement Cost Figures

106

$0

$5,000

$10,000

$15,000

$20,000

$25,000

Circular Concrete Pipewith Headwalls

Circular Concrete PipeProjecting from Fill

Concrete Arch Pipe withHeadwalls

Concrete Arch PipeProjecting from Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-1. Replacement Cost Using Circular and Arch Shaped Reinforced Concrete Pipe with Headwalls or Projecting from Fill

$0

$10,000

$20,000

$30,000

$40,000

$50,000

$60,000

Circular Concrete Pipewith Headwalls

Circular Concrete PipeProjecting from Fill

Concrete Arch Pipe withHeadwalls

Concrete Arch PipeProjecting from Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-2. Replacement Cost Using Circular and Arch Shaped Reinforced Concrete Pipe with Headwalls or Projecting from Fill

107

$0

$5,000

$10,000

$15,000

$20,000

$25,000

Concrete Boxes with Headwalls Concrete Boxes Projecting from Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-3. Replacement Cost Using Precast Concrete Box Culverts with Precast Headwalls or Projecting from Fill

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

$50,000

Concrete Boxes with Headwalls Concrete Boxes Projecting from Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-4. Replacement Cost Using Precast Concrete Box Culverts with Precast Headwalls or Projecting from Fill

108

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

$50,000

Circular Concrete Pipe withHeadwalls

Concrete Arch Pipe withHeadwalls

Concrete Boxes withHeadwalls

Labor Equipment Misc. Materials Major Structural Material

Figure E-5. Replacement Cost of Using Concrete Piping with Headwalls

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

$50,000

Circular Concrete PipeProjecting from Fill

Concrete Arch PipeProjecting from Fill

Concrete Boxes Projectingfrom Fill

Labor Equipment Misc. Materials Major Structural Mate

Figure E-6. Replacement Cost of Using Concrete Piping Projecting from Fill

109

$0

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

$14,000

Plain Galvanized MetalPipe with Headwalls

Plain Galvanized MetalPipe Projecting from Fill

Plain Galvanized MetalArch Pipe with

Headwalls

Plain Galvanized MetalArch Pipe Projecting

from Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-7. Replacement Cost Using Galvanized Metal Pipe with Headwalls or Projecting from Fill

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

Plain Galvanized MetalPipe with Headwalls

Plain Galvanized MetalPipe Projecting from Fill

Plain Galvanized MetalArch Pipe with

Headwalls

Plain Galvanized MetalArch Pipe Projecting

from Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-8. Replacement Cost Using Galvanized Metal Pipe with Headwalls or Projecting from Fill

110

$0

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

$14,000

Asphalt Coated Metal Arch Pipe withHeadwalls

Asphalt Coated Metal Arch Pipe Projectingfrom Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-9. Replacement Cost Using Asphalt Coated Metal Arch Pipe with Headwalls or Projecting from Fill

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

Asphalt Coated Metal Arch Pipe withHeadwalls

Asphalt Coated Metal Arch Pipe Projectingfrom Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-10. Replacement Cost Using Asphalt Coated Metal Arch Pipe with Headwalls or Projecting from Fill

111

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

$50,000

Circular ConcretePipe with Headwalls

Plain GalvanizedMetal Pipe with

Headwalls

Circular ConcretePipe Projecting from

Fill

Plain GalvanizedMetal Pipe

Projecting from Fill

Labor Equipment Misc. Materials Major Structural Material

Figure E-11. Replacement Cost Circular Reinforced Concrete Pipe versus Plain Galvanized Metal Pipe with Headwalls or Projecting from Fill

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

$50,000

Concrete Arch Pipewith Headwalls

Plain GalvanizedMetal Arch Pipe with

Headwalls

Concrete Arch PipeProjecting from Fill

Plain GalvanizedMetal Arch Pipe

Projecting from Fill

Labor Equipment Misc. Materials Major Structural Material

Figure E-12. Replacement Cost Arched Shaped Reinforced Concrete Pipe versus Plain Galvanized Metal Pipe with Headwalls or Projecting from Fill

112

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

$50,000

Concrete Arch Pipe withHeadwalls

Concrete Boxes withHeadwalls

Plain Galvanized Metal ArchPipe with Headwalls

Labor Equipment Misc. Materials Major Structural Material

Figure E-13. Replacement Cost Using Concrete Boxes and Arched Shaped Concrete and Metal Pipe with Headwalls

$0

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

Rehab Using Liners Rehab Using Glue Lam Panels

Labor Equipment Misc. Materials Liner or Panels

Figure E-14. Rehabilitation Using Pipe Liners or Glue Laminated Panel Sections

113

$0

$5,000

$10,000

$15,000

$20,000

$25,000

Rehab Using Liners Rehab Using Glue Lam Panels

Labor Equipment Misc. Materials Liner or Panels

Figure E-15. Rehabilitation Using Pipe Liners or Glue Laminated Panel Sections

$0

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

$14,000

$16,000

Rehab Using Liners Circular Concrete PipeProjecting from Fill

Plain Galvanized Metal PipeProjecting from Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-16. Cost of Rehabilitation Using Liners vs. Replacement Using Concrete or Metal Pipe

114

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

Rehab Using Liners Circular Concrete PipeProjecting from Fill

Plain Galvanized Metal PipeProjecting from Fill

Labor Equipment Misc. Materials Piping Materials

Figure E-17. Cost of Rehabilitation Using Liners vs. Replacement Using Concrete or Metal Pipe

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

$50,000

Replacement Using Precast ConcretePanels

Replacement Using Steel Super with CIPConcrete Deck

Labor Equipment Misc. Materials Deck and Superstructure

Figure E-18. Replacement Cost Using Precast Concrete Panel Sections or Steel Beams with a Cast in Place Concrete Deck

115

$0

$20,000

$40,000

$60,000

$80,000

$100,000

$120,000

$140,000

Replacement Using Precast ConcretePanels

Replacement Using Steel Super with CIPConcrete Deck

Labor Equipment Misc. Materials Deck and Superstructure

Figure E-19. Replacement Cost Using Precast Concrete Panel Sections or Steel Beams with a Cast in Place Concrete Deck

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

$40,000

$45,000

$50,000

Concrete Boxes with Headwalls Replacement Using PrecastConcrete Panels

Replacement Using SteelBeams and a CIP Concrete

Deck

Labor Equipment Misc. Materials Major Structural Material

Figure E-20. Replacement Cost Using Precast Box Culverts vs. Concrete Panel Sections or Steel Beams with a Cast in Place Concrete Deck

116

$0

$20,000

$40,000

$60,000

$80,000

$100,000

$120,000

Concrete Boxes with Headwalls Replacement Using PrecastConcrete Panels

Replacement Using Steel Beamsand a CIP Concrete Deck

Labor Equipment Misc. Materials Major Structural Material

Figure E-21. Replacement Cost Using Precast Concrete Panel Sections or Steel Beams with a Cast in Place Concrete Deck

117

Appendix F BRPD Bridge Replacement Feasibility Tables

118

Table F-1. Replacement Using Reinforced Concrete Pipe with Headwalls

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 5 280.00$ 1,400.00 $ 1 Project Manager 5 200.00$ 1,000.00 $ 1 Crew Supervisor 9 200.00$ 1,800.00 $ 1 Equipment Operator 3 180.00$ 540.00 $ 4 Crewman 9 130.00$ 4,680.00 $ 4 Truck Driver 2 130.00$ 1,040.00 $ 4 Flagman 2 120.00$ 960.00 $

Total $11,420

Equipment No. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00 $ 1 Loader 2 520.00$ 1,040.00 $ 1 Bulldozer 2 480.00$ 960.00 $ 1 Backhoe 3 480.00$ 1,440.00 $ 1 Roller 2 480.00$ 960.00 $ 4 Truck 2 440.00$ 3,520.00 $

Signs 2 500.00$ 1,000.00 $

Total $10,680

Miscellaneous Cost Quantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 25 Concrete 70.00$ 1,750.00$

2625 Reinforcing Steel 0.30$ 787.50$ Forming Materials 1,000.00$ 1,000.00$

215 #57 Stone 10.00$ 2,150.00$ 100 Chert Base 3.00$ 300.00$ 36 Dense Grade 11.50$ 414.00$

400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total $10,802

Piping Material Quantity Per Line (LF) Description Number of Lines Cost / LF Cost

48 RCP (72") 2 109.89$ 10,549.44 $

Total Replacement Cost == 43,450.94$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.The existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe. Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 57 sf (28.27 sf per line)

CY lbs. tons CY CY gal.

119

Table F-2. Replacement Using Reinforced Concrete Pipe Projecting From Fill

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 2 280.00$ 560.00$ 1 Project Manager 2 200.00$ 400.00$ 1 Crew Supervisor 3 200.00$ 600.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 3 130.00$ 1,560.00$ 4 Truck Driver 3 130.00$ 1,560.00$ 4 Flagman 2 120.00$ 960.00$

Total 6,180.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 3 480.00$ 1,440.00$ 1 Backhoe 2 480.00$ 960.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 3 440.00$ 5,280.00$

Signs 2 500.00$ 1,000.00$

Total 12,440.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 230 #57 Stone 10.00$ 2,300.00$ 250 Chert Base 3.00$ 750.00$ 36 Dense Grade 11.50$ 414.00$

400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total 7,864.00$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

66 RCP (72") 2 109.89$ 14,505.48$

Total Replacement Cost == 40,989.48$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.The existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe. Pipe end conditions were allowed to remain projecting from fill. New cross sectional area = 57 sf

tonsCYCYgal.

tonsCYCYgal.

120

Table F-3. Replacement Using Reinforced Concrete Arch Pipe with Headwalls

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 5 280.00$ 1,400.00$ 1 Project Manager 5 200.00$ 1,000.00$ 1 Crew Supervisor 9 200.00$ 1,800.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 9 130.00$ 4,680.00$ 4 Truck Driver 2 130.00$ 1,040.00$ 4 Flagman 2 120.00$ 960.00$

Total 11,420.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 2 480.00$ 960.00$ 1 Backhoe 3 480.00$ 1,440.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 2 440.00$ 3,520.00$

Signs 2 500.00$ 1,000.00$

Total 10,680.00$

Miscellaneous CostQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 25 Concrete 70.00$ 1,750.00$

2625 Reinforcing Steel 0.30$ 787.50$ Forming Materials 1,000.00$ 1,000.00$

215 #57 Stone 10.00$ 2,150.00$ 100 Chert Base 3.00$ 300.00$ 36 Dense Grade 11.50$ 414.00$ 400 Fuel 1.00$ 400.00$

1 Asphalt Patching 3,000.00$ 3,000.00$

Total 10,801.50$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

48 RCAP (102"x62") 2 159.81$ 15,341.76$

Total Replacement Cost == 48,243.26$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.The existing structure being replaced was one line of 14' x 8' corrugated metal arch pipe. Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 69.2 sf

tonsCYCYgal.

tonsCYCYgal.

CYlbs.

tonsCYCYgal.

121

Table F-4. Replacement Using Reinforced Concrete Arch Pipe Projecting From Fill

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 2 280.00$ 560.00$ 1 Project Manager 2 200.00$ 400.00$ 1 Crew Supervisor 3 200.00$ 600.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 3 130.00$ 1,560.00$ 4 Truck Driver 3 130.00$ 1,560.00$ 4 Flagman 2 120.00$ 960.00$

Total 6,180.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 3 480.00$ 1,440.00$ 1 Backhoe 2 480.00$ 960.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 3 440.00$ 5,280.00$

Signs 2 500.00$ 1,000.00$

Total 12,440.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 230 #57 Stone 10.00$ 2,300.00$ 250 Chert Base 3.00$ 750.00$ 36 Dense Grade 11.50$ 414.00$

400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total 7,864.00$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

66 RCAP (102"x62") 2 159.81$ 21,094.92$

Total Replacement Cost == 47,578.92$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.The existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe. Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 69.2 sf

tonsCYCYgal.

tonsCYCYgal.

122

Table F-5. Replacement Using Reinforced Concrete Box Culverts with Headwalls

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 5 280.00$ 1,400.00$ 1 Project Manager 5 200.00$ 1,000.00$ 1 Crew Supervisor 5 200.00$ 1,000.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 5 130.00$ 2,600.00$ 4 Truck Driver 2 130.00$ 1,040.00$ 4 Flagman 2 120.00$ 960.00$

Total 8,540.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 2 480.00$ 960.00$ 1 Backhoe 3 480.00$ 1,440.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 2 440.00$ 3,520.00$

Signs 2 500.00$ 1,000.00$

Total 10,680.00$

Miscellaneous CostQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 4 Precast Parapets 101.00$ 404.00$ 4 Precast Wingwalls 419.00$ 1,676.00$ 7 Concrete 70.00$ 490.00$

400 Reinforcing Steel 0.30$ 120.00$ 205 #57 Stone 10.00$ 2,050.00$ 100 Chert Base 3.00$ 300.00$ 36 Dense Grade 11.50$ 414.00$ 400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total 8,854.00$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

48 RCBC (6'x5') 2 156.00$ 14,976.00$

Total Replacement Cost == 43,050.00$

Notes : The existing structure was removed and replaced while a temporary detour carried traffic flow. This cost was not included in the replacement cost because in some cases traffic may be rerouted along an alternate route during construction. The existing structure being replaced was a 16 foot span timber bridge. Pipe end conditions were treated with precast wingwalls. 2 lines of 6ftx5ft box culverts (2420 lbs./LF) were used rather than 10ftx6ft (4924 lbs./LF) because of reduced weightNew cross sectional area = 60 sf

tons

CYgal.

tons

CYgal.

CYlbs.tons

CY

gal.

123

Table F-6. Replacement Using Reinforced Concrete Box Culverts Projecting from Fill

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 3 280.00$ 840.00$ 1 Project Manager 3 200.00$ 600.00$ 1 Crew Supervisor 3 200.00$ 600.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 3 130.00$ 1,560.00$ 4 Truck Driver 3 130.00$ 1,560.00$ 4 Flagman 2 120.00$ 960.00$

Total 6,660.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 3 480.00$ 1,440.00$ 1 Backhoe 2 480.00$ 960.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 3 440.00$ 5,280.00$

Signs 2 500.00$ 1,000.00$

Total 12,440.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

5 Concrete 70.00$ 350.00$ 220 #57 Stone 10.00$ 2,200.00$ 250 Chert Base 3.00$ 750.00$ 36 Dense Grade 11.50$ 414.00$ 400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total 7,114.00$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

66 RCBC (6'x5') 2 156.59$ 20,669.88$

Total Replacement Cost == 46,883.88$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the replacement effort. Shoulder was temporarily built out on one side appoximately ten feet to allow construction to progress with traffic flow diverted. Existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe. Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 60 sf

CYtonsCYCYgal.

CYtonsCYCYgal.

124

Table F-7. Replacement Using Plain Galvanized Pipe with Headwalls

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 5 280.00$ 1,400.00$ 1 Project Manager 5 200.00$ 1,000.00$ 1 Crew Supervisor 9 200.00$ 1,800.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 9 130.00$ 4,680.00$ 4 Truck Driver 2 130.00$ 1,040.00$ 4 Flagman 2 120.00$ 960.00$

Total 11,420.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 2 480.00$ 960.00$ 1 Backhoe 3 480.00$ 1,440.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 2 440.00$ 3,520.00$

Signs 2 500.00$ 1,000.00$

Total 10,680.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 25 Concrete 70.00$ 1,750.00$

2625 Reinforcing Steel 0.30$ 787.50$ Forming Materials 1,000.00$ 1,000.00$

215 #57 Stone 10.00$ 2,150.00$ 100 Chert Base 3.00$ 300.00$ 36 Dense Grade 11.50$ 414.00$ 400 Fuel 1.00$ 400.00$

1 Asphalt Patching 3,000.00$ 3,000.00$

Total 10,801.50$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

48 GMP (72") 2 31.95$ 3,067.20$

Total Replacement Cost == 35,968.70$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.The existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe. Plain galvanized metal pipe used was 14 gauge metal.Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 57 sf (28.27 sf per line)

CYlbs.

tonsCYCYgal.

CYlbs.

tonsCYCYgal.

125

Table F-8. Replacement Using Plain Galvanized Pipe Projecting from Fill

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 2 280.00$ 560.00$ 1 Project Manager 2 200.00$ 400.00$ 1 Crew Supervisor 3 200.00$ 600.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 3 130.00$ 1,560.00$ 4 Truck Driver 3 130.00$ 1,560.00$ 4 Flagman 2 120.00$ 960.00$

Total 6,180.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 3 480.00$ 1,440.00$ 1 Backhoe 2 480.00$ 960.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 3 440.00$ 5,280.00$

Signs 2 500.00$ 1,000.00$

Total 12,440.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 230 #57 Stone 10.00$ 2,300.00$ 250 Chert Base 3.00$ 750.00$ 36 Dense Grade 11.50$ 414.00$

400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total 7,864.00$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

66 GMP (72") 2 31.95$ 4,217.40$

Total Replacement Cost == 30,701.40$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.Existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe. Plain galvanized metal pipe used was 14 gauge metal.Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 57 sf

tonsCYCYgal.

tonsCYCYgal.

126

Table F-9. Replacement Using Plain Galvanized Arch Pipe with Headwalls

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 5 280.00$ 1,400.00$ 1 Project Manager 5 200.00$ 1,000.00$ 1 Crew Supervisor 9 200.00$ 1,800.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 9 130.00$ 4,680.00$ 4 Truck Driver 2 130.00$ 1,040.00$ 4 Flagman 2 120.00$ 960.00$

Total 11,420.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 2 480.00$ 960.00$ 1 Backhoe 3 480.00$ 1,440.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 2 440.00$ 3,520.00$

Signs 2 500.00$ 1,000.00$

Total 10,680.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 25 Concrete 70.00$ 1,750.00$

2625 Reinforcing Steel 0.30$ 787.50$ Forming Materials 1,000.00$ 1,000.00$

215 #57 Stone 10.00$ 2,150.00$ 100 Chert Base 3.00$ 300.00$ 36 Dense Grade 11.50$ 414.00$

400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total 10,801.50$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

48 GMAP (95"x67") 2 74.00$ 7,104.00$

Total Replacement Cost == 40,005.50$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.The existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe. Galvanized arch pipe used was 10 gauge metal.Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 72.6 sf

CYlbs.

tonsCYCYgal.

CYlbs.

tonsCYCYgal.

127

Table F-10. Replacement Using Plain Galvanized Arch Pipe Projecting from Fill

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 2 280.00$ 560.00$ 1 Project Manager 2 200.00$ 400.00$ 1 Crew Supervisor 3 200.00$ 600.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 3 130.00$ 1,560.00$ 4 Truck Driver 3 130.00$ 1,560.00$ 4 Flagman 2 120.00$ 960.00$

Total 6,180.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 3 480.00$ 1,440.00$ 1 Backhoe 2 480.00$ 960.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 3 440.00$ 5,280.00$

Signs 2 500.00$ 1,000.00$

Total 12,440.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 230 #57 Stone 10.00$ 2,300.00$ 250 Chert Base 3.00$ 750.00$ 36 Dense Grade 11.50$ 414.00$ 400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total 7,864.00$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

66 GMAP (95"x67") 2 74.00$ 9,768.00$

Total Replacement Cost == 36,252.00$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.Existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe. Galvanized arch pipe used was 10 gauge metal.Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 72.6 sf

tonsCYCYgal.

tonsCYCYgal.

128

Table F-11. Replacement Using Asphalt Coated Metal Arch Pipe with Paved Invert with Headwalls

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 5 280.00$ 1,400.00$ 1 Project Manager 5 200.00$ 1,000.00$ 1 Crew Supervisor 9 200.00$ 1,800.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 9 130.00$ 4,680.00$ 4 Truck Driver 2 130.00$ 1,040.00$ 4 Flagman 2 120.00$ 960.00$

Total 11,420.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 2 480.00$ 960.00$ 1 Backhoe 3 480.00$ 1,440.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 2 440.00$ 3,520.00$

Signs 2 500.00$ 1,000.00$

Total 10,680.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 25 Concrete 70.00$ 1,750.00$

2625 Reinforcing Steel 0.30$ 787.50$ Forming Materials 1,000.00$ 1,000.00$

215 #57 Stone 10.00$ 2,150.00$ 100 Chert Base 3.00$ 300.00$ 36 Dense Grade 11.50$ 414.00$ 400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total 10,801.50$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

48 ACGMAP (95"x67") 2 94.95$ 9,115.20$

Total Replacement Cost == 42,016.70$

Notes: Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.The existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe. Metal pipe with asphalt coating, paved invert and 10 gauge metal.Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 72.6 sf

CYlbs.

tonsCYCYgal.

CYlbs.

tonsCYCYgal.

129

Table F-12. Replacement Using Asphalt Coated Metal Arch Pipe with Paved Invert Projecting from Fill

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 2 280.00$ 560.00$ 1 Project Manager 2 200.00$ 400.00$ 1 Crew Supervisor 3 200.00$ 600.00$ 1 Equipment Operator 3 180.00$ 540.00$ 4 Crewman 3 130.00$ 1,560.00$ 4 Truck Driver 3 130.00$ 1,560.00$ 4 Flagman 2 120.00$ 960.00$

Total 6,180.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Trackhoe 2 880.00$ 1,760.00$ 1 Loader 2 520.00$ 1,040.00$ 1 Bulldozer 3 480.00$ 1,440.00$ 1 Backhoe 2 480.00$ 960.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 3 440.00$ 5,280.00$

Signs 2 500.00$ 1,000.00$

Total 12,440.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 1,000.00$ 1,000.00$ 230 #57 Stone 10.00$ 2,300.00$ 250 Chert Base 3.00$ 750.00$ 36 Dense Grade 11.50$ 414.00$ 400 Fuel 1.00$ 400.00$ 1 Asphalt Patching 3,000.00$ 3,000.00$

Total 7,864.00$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

66 ACGMAP (95"x67") 2 94.95$ 12,533.40$

Total Replacement Cost == 39,017.40$

Notes : Existing pipe was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.The existing structure being replaced was two lines of 84"x72" corrugated metal arch pipe.

Metal pipe with asphalt coating, paved invert and 10 gauge metal.Pipe end conditions were treated with cast in place headwalls. New cross sectional area = 72.6 sf

tonsCYCYgal.

tonsCYCYgal.

130

Table F-13. Rehabilitation Using Liner Pipes

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 1 280.00$ 280.00$ 1 Project Manager 2 200.00$ 400.00$ 1 Crew Supervisor 2 200.00$ 400.00$ 1 Equipment Operator 2 180.00$ 360.00$ 4 Crewman 2 130.00$ 1,040.00$ 4 Truck Driver 1 130.00$ 520.00$ 2 Flagman 1 120.00$ 240.00$

Total 3,240.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Backhoe 2 450.00$ 900.00$ 1 Bulldozer 1 480.00$ 480.00$ 1 Truck 1 440.00$ 440.00$

Total 1,820.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 500.00$ 500.00$ 38 Grout Material 120.00$ 4,560.00$ 70 Chert Base 3.00$ 210.00$

100 Fuel 1.00$ 100.00$

Total 4,870.00$

Piping MaterialQuantity Per Line (LF) Description Number of Lines Cost / LF Cost

66 Aluminized Metal Pipe (72") 2 85.00$ 11,220.00$

Total Replacement Cost == 21,150.00$

Notes : A 72" 12 gauge double walled Aluminized Ultra Smooth Flow (Manning's "n" 0.012) metal pipe was used to line the existing 84" corrugated metal pipes. Flowable grout material was used to fill the residual area between the liner and the existing pipe.Traffic control was necessary for the limited time that was needed to unload and insert the pipe and fill material into place.Pipe end conditions were allowed to remain projecting from fill. New cross sectional area = 57 sf

CYCYgal.

CYCYgal.

131

Table F-14. Rehabilitation Using Glue Laminated Timber Panels

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 1 280.00$ 280.00$ 1 Project Manager 1 200.00$ 200.00$ 1 Crew Supervisor 2 200.00$ 400.00$ 1 Equipment Operator 2 180.00$ 360.00$ 4 Crewman 2 130.00$ 1,040.00$ 4 Truck Driver 2 130.00$ 1,040.00$ 4 Flagman 2 120.00$ 960.00$

Total 4,280.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Backhoe 1 450.00$ 450.00$ 1 Truck 1 440.00$ 440.00$ 1 Signs 1 500.00$ 500.00$

Total 1,390.00$

Miscellaneous MaterialsQuantity Description Unit Cost Cost

Mobilization 250.00$ 250.00$ 40 Chirt Base 3.00$ 120.00$ 10 Dense Grade 11.50$ 115.00$ 125 Fuel 1.00$ 125.00$ 1 Asphalt Patching 400.00$ 400.00$

Total 760.00$

Timber MaterialLength Per Panel (LF) Description Number of Panels Cost / LF Cost

17 4'x8" Glue Lam Panels 7 95.60$ 11,376.40$

Total Replacement Cost == 17,806.40$

Notes : Existing deck was removed and replaced one lane at a time allowing traffic to flow with the aid of effective traffic control in place throughout the course of the replacement effort.Existing structure being replaced was a deteriorated one lane timber bridge. The abutments and other substructure was in good conditions showing little deterioration.

CYCYgal.

132

Table F-15. Replacement Using Precast Concrete Span Sections with Concrete Abutments

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 8 280.00$ 2,240.00$ 1 Project Manager 15 200.00$ 3,000.00$ 1 Crew Supervisor 25 200.00$ 5,000.00$ 1 Equipment Operator 25 180.00$ 4,500.00$ 4 Crewman 25 130.00$ 13,000.00$ 4 Truck Driver 7 130.00$ 3,640.00$

Total 31,380.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Crane 20 900.00$ 18,000.00$ 1 Trackhoe 10 880.00$ 8,800.00$ 1 Loader 5 520.00$ 2,600.00$ 1 Bulldozer 3 480.00$ 1,440.00$ 1 Backhoe 10 480.00$ 4,800.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 7 440.00$ 12,320.00$

Signs 25 500.00$ 12,500.00$

Total 43,420.00$

Miscellaneous CostQuantity Description Unit Cost Cost

Mobilization 2,000.00$ 2,000.00$ 105 Concrete 70.00$ 7,350.00$

21200 Reinforcing Steel 0.30$ 6,360.00$ Forming Materials 2,500.00$ 2,500.00$

235 #57 Stone 10.00$ 2,350.00$ 175 Chert Base 3.00$ 525.00$ 55 Dense Grade 11.50$ 632.50$

950 Fuel 1.00$ 950.00$ 200 Silt Fence (Type A) 2.00$ 400.00$ 120 Rip Rap (Class II) 7.00$ 840.00$

1 Asphalt Patching 5,000.00$ 5,000.00$

Total 28,907.50$

Deck and Superstructure Quantity Description Cost / Each Cost

2 20' x 1'3" x 4'1" Barrier Rail 1,462.00$ 2,924.00$ 2 20' x 3'6" x 1'5" Exterior Span Section 1,598.00$ 3,196.00$ 6 20' x 3'6" x 1'5" Interior Span Section 1,346.00$ 8,076.00$

Total 14,196.00$

Total Replacement Cost == 111,783.50$

Notes : The existing structure was removed and replaced while traffic was rerouted along an alternate route. The existing structure being replaced was a 18 foot timber LT-20.

CYlbs.

tonsCYCYgal.

tonsfeet

133

Table F-16. Replacement Using Steel Beam Superstructure with a Cast in Place Concrete Deck

Personnel No. Required Job Description Working Days Cost / Day Cost

1 Superintendent 8 280.00$ 2,240.00$ 1 Project Manager 18 200.00$ 3,600.00$ 1 Crew Supervisor 30 200.00$ 6,000.00$ 1 Equipment Operator 30 180.00$ 5,400.00$ 4 Crewman 30 130.00$ 15,600.00$ 4 Truck Driver 7 130.00$ 3,640.00$

Total 36,480.00$

EquipmentNo. Required Description Working Days Cost / Day Cost

1 Crane 5 900.00$ 4,500.00$ 1 Trackhoe 10 880.00$ 8,800.00$ 1 Loader 5 520.00$ 2,600.00$ 1 Bulldozer 3 480.00$ 1,440.00$ 1 Backhoe 10 480.00$ 4,800.00$ 1 Roller 2 480.00$ 960.00$ 4 Truck 7 440.00$ 12,320.00$

Signs 30 500.00$ 15,000.00$

Total 45,920.00$

Miscellaneous CostQuantity Description Unit Cost Cost

Mobilization 2,000.00$ 2,000.00$ 105 Concrete 70.00$ 7,350.00$

21200 Reinforcing Steel 0.30$ 6,360.00$ Forming Materials 2,500.00$ 2,500.00$

235 #57 Stone 10.00$ 2,350.00$ 175 Chert Base 3.00$ 525.00$ 55 Dense Grade 11.50$ 632.50$

800 Fuel 1.00$ 800.00$ 200 Silt Fence (Type A) 2.00$ 400.00$ 120 Rip Rap (Class II) 7.00$ 840.00$ 1 Asphalt Patching 5,000.00$ 5,000.00$

Total 28,757.50$

Deck and SuperstructureQuantity Description Cost / Each Cost

4 20' W18x35 A36 Weathering Steel Beams 420.00$ 1,680.00$ 20 Concrete 70.00$ 1,400.00$

7900 Reinforcing Steel 0.30$ 2,370.00$ Forming Materials 2,000.00$ 2,000.00$ Total 7,450.00$

Total Replacement Cost == 118,607.50$

Notes : The existing structure was removed and replaced while traffic was rerouted along an alternate route. The existing structure being replaced was a 18 foot timber LT-20.

CYlbs.

tonsCYCYgal.

tonsfeet

CYCYlbs.

134

Appendix G BRPD Photographic Record

135

Figure G-22. Timber Bridge Failure

Figure G-23. Typical Deteriorated Timber LT20

136

Figure G-24. Deteriorated Deck and Superstructure

Figure G-25. Misalignment of Substructure

137

Figure G-26. Severe Erosion

Figure G-27. Crushing of the Cap on a Short Span Timber LT20 (~5 feet)

138

Figure G-28. Rehabilitated LT20 Using a Temporary Steel Pile Bent

Figure G-29. LT20 with Steel Beams and a Cast in Place Concrete Deck

139

Figure G-30. Typical Corrugated Metal LT20

Figure G-31. Deteriorated Corrugated Metal Pipe

140

Figure G-32. Removal of a deteriorated LT20

Figure G-33. Placement of Bedding Material

141

Figure G-34. Laying Reinforced Concrete Arch Pipes with a Trackhoe

Figure G-35. Reinforced Concrete Pipe with Cast in Place Concrete Headwall

142

Figure G-36. Reinforced Concrete Arch Pipe Projecting from Fill with Riprap in Place

Figure G-37. Galvanized Metal Pipe Projecting from Fill

143

Figure G-38. Using a Crane to Lay Precast Reinforced Concrete Boxes

Figure G-39. Reinforced Concrete Box with Precast Wingwalls

144

Figure G-40. Double Line of Concrete Boxes with Precast Wingwalls

Figure G-41. Double Line of Concrete Boxes Projecting from Fill

145

Figure G-42. Pulling Liner Inside Existing Pipe

Figure G-43. Rehabilitation Using Liner Pipes

146

Figure G-44. Rehabilitation Using Timber Glue Laminated Panels

Figure G-45. Concrete Bridge Abutment

147

Figure G-46. Abutment for Precast Concrete Span Sections

Figure G-47. Setting Precast Concrete Span Sections

148

Figure G-48. Setting Precast Concrete Parapets

Figure G-49. Precast Concrete Bridge Built of Span Sections

149

Figure G-50. Steel Beams with a Cast in Place Concrete Deck

150

Appendix H NBIS Condition Ratings in Shelby County

151

2001 ROUTINE CYCLE 1999 ROUTINE CYCLE 1997 ROUTINE CYCLE BIN DECK SUPER SUB CHAN CULV DECK SUPER SUB CHAN CULV DECK SUPER SUB CHAN CULV

YR BLT

25 0 0 0 0 0 2 2 2 5 N 2 2 2 6 N 1905

99 0 0 0 0 0 0 0 4 6 N 0 0 4 6 N 1915

198 5 5 6 N N 5 5 6 N N 5 5 6 N N 1922

725 0 0 3 3 N 0 0 3 3 N 0 0 3 3 N 1930

932 N N N 6 7 N N N 6 7 N N N 6 7 1931

933 6 7 7 6 N 6 7 7 6 N 6 7 7 6 N 1931

934 6 6 6 N N 6 6 6 N N 6 6 6 N N 1939

935 6 7 6 5 N 6 7 6 5 N 6 7 6 5 N 1931

936 N N N 5 7 N N N 5 7 N N N 5 7 1931

937 N N N 5 7 N N N 5 7 N N N 5 7 1931

938 N N N 5 7 N N N 5 7 N N N 5 7 1931

939 N N N 5 7 N N N 5 7 N N N 5 7 1931

940 N N N 5 7 N N N 5 7 N N N 5 7 1931

941 6 7 6 4 N 6 7 6 4 N 6 7 6 4 N 1931

1049 6 7 7 6 N 7 7 7 6 N 7 7 7 6 N 1933

1172 6 6 5 5 N 6 6 5 5 N 6 6 5 5 N 1935

1938 4 4 5 6 N 4 4 5 6 N 4 4 5 6 N 1939

1939 4 4 5 5 N 4 4 5 5 N 4 4 5 5 N 1939

1940 6 6 4 5 N 6 6 4 5 N 6 6 4 5 N 1939

1941 5 6 4 5 N 5 6 4 5 N 5 6 4 5 N 1939

2198 5 6 6 6 N 5 6 6 6 N 5 6 6 6 N 1940

2380 7 6 7 7 N 7 6 7 7 N 7 6 7 7 N 1940

2429 0 0 0 0 0 5 4 6 N N 5 4 6 N N 1940

2488 6 7 6 5 N 6 7 6 5 N 6 7 6 5 N 1940

2847 7 6 6 5 N 7 6 6 5 N 7 6 6 5 N 1945

3267 7 7 7 6 N 7 7 7 6 N 7 7 7 6 N 1948

3620 0 0 0 0 0 5 5 4 4 N 2 3 5 6 N 1950

3726 N N N 5 7 N N N 5 7 N N N 5 7 1950

4080 N N N 5 6 --- --- --- --- --- 3 4 3 4 N 1951

4883 N N N 6 7 N N N 5 6 N N N 5 6 1954

5369 6 7 5 4 N N N N 6 7 N N N 6 7 1955

5517 N N N 6 7 6 7 5 4 N 7 7 5 4 N 1956

5587 N N N 6 7 N N N 6 7 N N N 6 7 1956

5588 N N N 4 6 N N N 6 7 N N N 6 7 1956

5840 7 7 6 6 N N N N 4 6 N N N 4 6 1957

5841 N N N 6 7 7 7 6 6 N 7 7 6 6 N 1957

5842 N N N 6 7 N N N 6 7 N N N 6 7 1957

5998 4 4 4 4 N N N N 6 7 N N N 6 7 1957

6332 6 7 7 6 N 6 6 6 5 N 6 6 6 5 N 1958

6333 6 6 5 5 N 6 7 7 6 N 6 7 7 6 N 1958

6363 5 5 5 6 N 6 6 5 5 N 6 6 5 5 N 1958

6595 0 0 0 0 0 5 5 5 6 N 5 5 5 6 N 1959

6596 6 6 5 5 N --- --- --- --- --- 6 6 5 5 N 1959

152

2001 ROUTINE CYCLE 1999 ROUTINE CYCLE 1997 ROUTINE CYCLE BIN DECK SUPER SUB CHAN CULV DECK SUPER SUB CHAN CULV DECK SUPER SUB CHAN CULV

YR BLT

6726 0 0 0 0 0 6 6 5 5 N 6 6 5 5 N 1959 6880 3 3 3 6 N --- --- --- --- --- 4 5 3 4 N 1960 6881 4 4 4 4 N 3 3 3 6 N 3 4 3 6 N 1960 6882 5 6 6 6 N 4 4 4 4 N 4 4 4 4 N 1960 6952 7 7 7 7 N 5 6 6 6 N 5 6 6 6 N 1960 6965 N N N 7 7 7 7 7 7 N 7 7 7 7 N 1960 7293 5 6 5 6 N N N N 7 7 N N N 7 7 1961 7294 5 6 5 5 N 6 6 5 6 N 6 6 5 6 N 1961 7390 7 7 7 7 N 5 6 5 5 N 5 6 5 5 N 1961 7594 7 7 5 5 N 7 7 7 7 N 7 7 7 7 N 1962 7653 N N N 4 7 7 7 5 5 N 7 7 5 5 N 1962 7897 6 7 7 6 N N N N 4 7 N N N 4 7 1963 7973 N N N 6 7 6 7 7 6 N 6 7 3 3 N 1963 8032 N N N 7 6 N N N 6 7 N N N 6 7 1963 8033 7 7 7 7 N N N N 7 6 N N N 7 6 1963 8091 0 0 0 0 0 7 7 7 7 N 7 7 7 7 N 1963 8092 3 3 2 4 N 2 2 2 5 N 2 2 2 5 N 1963 8313 4 5 3 4 N 2 3 2 4 N 2 3 2 5 N 1964 8378 0 0 0 0 0 4 6 3 4 N 4 5 3 4 N 1964 8379 0 0 0 0 0 0 0 6 5 N 0 0 6 5 N 1964 8927 0 0 0 0 0 --- --- --- --- --- 4 4 3 2 N 1965 8928 0 0 0 0 0 5 5 5 4 N 5 5 5 5 N 1965 9085 0 0 0 0 0 --- --- --- --- --- 5 5 5 6 N 1966 9374 7 6 7 4 N --- --- --- --- --- 3 4 3 5 N 1967 9694 7 6 6 6 N 7 6 7 4 N 7 6 7 4 N 1968 9778 4 5 4 4 N 6 6 6 6 N 6 6 6 6 N 1968 10061 0 0 0 0 0 4 5 4 4 N 4 4 4 4 N 1969 10118 0 0 0 0 0 --- --- --- --- --- 5 5 4 4 N 1969 10357 7 7 6 N N --- --- --- --- --- 3 4 3 5 N 1970 10406 0 0 0 0 0 7 7 6 N N 7 7 6 N N 1970 10438 6 7 6 6 N 6 6 6 5 N 6 6 6 5 N 1970 10579 7 7 7 7 N 6 7 6 6 N 6 7 6 6 N 1971 10580 7 7 7 7 N 7 7 7 7 N 7 7 7 7 N 1971 10607 3 4 4 3 N 7 7 7 7 N 7 7 7 7 N 1971 10825 6 7 6 6 N 4 5 4 3 N 7 5 4 5 N 1972 11015 7 7 7 7 N 6 7 6 6 N 6 7 6 6 N 1973 11378 7 6 6 6 N 7 7 7 7 N 7 7 7 7 N 1975 11591 0 0 0 0 0 5 6 6 6 N 5 6 6 6 N 1976 11779 4 6 6 5 N --- --- --- --- --- 6 6 4 5 N 1977 11780 3 5 5 N N 4 6 6 5 N 4 6 6 5 N 1977 11953 3 6 6 6 N 3 5 5 N N 5 5 5 N N 1978 12024 7 7 7 7 N 3 6 6 6 N 3 7 6 6 N 1978 12033 N N N 7 7 7 7 7 7 N 7 7 7 7 N 1978 12572 5 7 7 6 N N N N 7 7 N N N 7 7 1981

153

2001 ROUTINE CYCLE 1999 ROUTINE CYCLE 1997 ROUTINE CYCLE BIN DECK SUPER SUB CHAN CULV DECK SUPER SUB CHAN CULV DECK SUPER SUB CHAN CULV

YR BLT

12580 7 7 7 6 N 6 7 7 6 N 6 7 7 6 N 1981 12945 7 7 8 6 N 7 7 7 6 N 7 7 7 6 N 1983 13032 7 7 7 6 N 7 7 8 6 N 7 7 8 6 N 1983 13308 N N N 6 7 7 7 7 6 N 7 7 7 6 N 1984 13326 N N N 6 7 N N N 6 7 N N N 6 7 1984 13354 N N N 6 7 N N N 6 7 N N N 6 7 1984 13603 N N N 7 7 N N N 6 7 N N N 6 7 1985 13654 7 7 7 4 N N N N 7 7 N N N 7 7 1985 13751 7 6 6 5 N 7 7 7 4 N 7 7 7 4 N 1937 13755 7 6 6 6 N 7 6 6 5 N 7 6 6 5 N 1938 13760 7 7 6 6 N 7 6 6 6 N 7 6 6 6 N 1941 13783 6 7 6 5 N 7 7 6 6 N 7 7 6 6 N 1951 13976 N N N 6 7 6 7 6 5 N 6 7 6 5 N 1986 14022 7 7 7 7 N N N N 6 7 N N N 6 7 1986 14029 6 6 7 7 N 7 7 7 7 N 7 7 7 7 N 1986 14237 7 7 7 7 N 6 6 7 7 N 6 6 7 7 N 1987 14238 N N N 7 7 7 7 7 7 N 7 7 7 7 N 1987 14369 6 7 6 6 N N N N 7 7 N N N 7 7 1961 14374 0 0 0 0 0 6 7 6 6 N 6 7 6 6 N 1963 14493 6 6 6 5 N 6 6 6 5 N 5 5 5 5 N 1988 14494 5 4 5 5 N 5 4 5 5 N 6 6 6 5 N 1988 14495 0 0 0 0 0 4 5 4 4 N 5 5 6 6 N 1988 14542 N N N 6 7 N N N 6 7 4 5 4 4 N 1988 14607 N N N 6 7 N N N 6 7 N N N 6 7 1988 14725 6 6 6 6 N 6 6 6 6 N N N N 6 7 1959 14906 N N N 7 8 N N N 7 8 6 6 6 6 N 1989 14913 8 8 7 6 N 8 8 8 6 N N N N 7 8 1989 14928 N N N 6 7 N N N 6 7 8 8 8 6 N 1989 14984 5 6 5 5 N 6 6 5 5 N N N N 6 7 1935 14987 4 5 5 6 N 4 5 5 6 N 6 6 5 5 N 1938 15009 4 2 2 4 N 5 2 2 4 N 4 5 5 6 N 1959 15010 7 7 6 5 N 7 7 6 5 N 6 4 2 5 N 1960 15159 7 7 7 7 N 7 7 7 7 N 7 7 7 5 N 1990 15190 N N N 7 8 N N N 7 8 7 7 7 7 N 1990 15209 7 7 7 6 N 7 7 7 6 N N N N 7 8 1990 15221 N N N 6 8 N N N 6 8 7 7 7 6 N 1990 15592 N N N 5 5 N N N 5 5 N N N 6 8 1971 15593 N N N 6 6 N N N 6 6 N N N 5 5 1981 15596 N N N 7 7 N N N 7 7 N N N 6 6 1973 15598 N N N 7 8 N N N 7 8 N N N 7 7 1992 15600 N N N 6 6 N N N 6 6 N N N 7 8 1952 15602 N N N 6 6 N N N 6 6 N N N 6 6 1955 15603 N N N 6 7 N N N 6 7 N N N 6 6 1937 15604 N N N 7 7 N N N 7 7 N N N 6 7 1937

154

2001 ROUTINE CYCLE 1999 ROUTINE CYCLE 1997 ROUTINE CYCLE BIN DECK SUPER SUB CHAN CULV DECK SUPER SUB CHAN CULV DECK SUPER SUB CHAN CULV

YR BLT

15615 N N N 6 7 N N N 6 7 N N N 7 7 1984 15617 7 8 7 7 N 7 8 7 7 N N N N 6 7 1992 15618 N N N 7 7 N N N 7 7 7 8 7 7 N 1992 15619 N N N 6 7 N N N 7 7 N N N 7 7 1992 15729 N N N 7 8 N N N 7 8 N N N 7 7 1993 15754 N N N 7 7 N N N 7 7 N N N 7 8 1993 15755 N N N 6 7 N N N 6 7 N N N 7 7 1993 16440 N N N 8 9 N N N 8 9 N N N 6 7 1981 16441 N N N 7 8 N N N 7 8 N N N 8 9 1995 16442 N N N 6 8 N N N 6 8 N N N 7 8 1995 16443 8 8 8 7 N 8 8 8 7 N N N N 6 8 1995 16722 8 8 8 7 N --- --- --- --- --- 8 8 8 7 N 1996 16822 N N N 6 7 N N N 6 7 N N N 6 7 1952 16823 N N N 5 8 N N N 5 8 N N N 6 7 1963 16824 9 8 9 6 N 9 9 9 6 N N N N 5 8 1996 16859 9 9 9 8 N 9 9 9 8 N 9 9 9 6 N 1996 16860 8 6 5 6 N 8 6 5 6 N 9 9 9 8 N 1963 16861 N N N 8 8 N N N 8 8 8 6 5 6 N 1987 16862 N N N 6 8 N N N 6 8 N N N 8 8 1996 16881 N N N 6 N N N N 6 N N N N 8 9 1997 17091 9 9 9 9 N 9 9 9 9 N N N N 6 N 1970 17178 8 8 8 8 N 8 8 8 8 N --- --- --- --- --- 1997 17179 N N N 8 8 N N N 8 8 --- --- --- --- --- 1999 17211 N N N 7 9 N N N 8 9 N N N 8 8 1997 17257 N N N 8 9 N N N 8 9 --- --- --- --- --- 1997 17263 N 8 8 8 N N 8 8 8 N --- --- --- --- --- 1998 17282 N 9 8 7 N N 9 8 7 N --- --- --- --- --- 1997 17284 N 9 9 8 N N 9 9 8 N --- --- --- --- --- 1998 17396 N N N 8 9 N N N 8 9 --- --- --- --- --- 1998 17461 9 9 9 N N 9 9 9 N N --- --- --- --- --- 1999 17512 9 9 9 8 N 9 9 9 8 N --- --- --- --- --- 1999 17513 N N N 8 9 N N N 8 9 --- --- --- --- --- 1999 17514 9 9 9 8 N 9 9 9 8 N --- --- --- --- --- 1999 17795 9 9 9 8 N --- --- --- --- --- --- --- --- --- --- 2000 17796 9 9 9 8 N --- --- --- --- --- --- --- --- --- --- 2000 17797 9 9 9 9 N --- --- --- --- --- --- --- --- --- --- 2000 18127 N N N 8 8 --- --- --- --- --- --- --- --- --- --- 1998 17845 9 9 9 8 N --- --- --- --- --- --- --- --- --- --- 2000 17876 9 9 9 8 N --- --- --- --- --- --- --- --- --- --- 2000 17983 9 9 9 N N --- --- --- --- --- --- --- --- --- --- 2000 17984 N N N 7 8 --- --- --- --- --- --- --- --- --- --- 2000

155

Appendix I Initial Markov Probability Matrices

156

Deck Transition Matrix 1999 to 2001 Condition 9 8 7 6 5 4 3 2 q0 1 0 0 0 0 0 0 0 TX 6 5 16 11 4 4 1 1 TX-1 0 0 3 4 1 1 0 0 TX-TX-1 6 5 19 15 5 5 1 1 TX to TX 1 1 0.842105 0.733333 0.8 0.8 1 1 TX to TX-1 0 0 0.157895 0.266667 0.2 0.2 0 0 N 2

Figure I-1. Deck Transition Matrix 1999 to 2001

Deck Transition Matrix 1997 to 1999 Condition 9 8 7 6 5 4 3 2q0 1 0 0 0 0 0 0 0 TX 1 1 25 22 9 7 2 1TX-1 1 0 2 2 2 1 0 0TX-TX-1 2 1 27 24 11 8 2 1TX to TX 0.5 1 0.925926 0.916667 0.818182 0.875 1 1TX to TX-1 0.5 0 0.074074 0.083333 0.181818 0.125 0 0 N 2

Figure I-2. Deck Transition Matrix 1997 to 1999

Superstructure Transition Matrix 1999 to 2001

157

Condition 9 8 7 6 5 4 3 2 q0 1 0 0 0 0 0 0 0 TX 7 6 17 8 2 3 0 1 TX-1 1 0 4 6 0 0 0 0 TX-TX-1 8 6 21 14 2 3 0 1 TX to TX 0.875 1 0.8095 0.5714 1 1 0 1 TX to TX-1 0.125 0 0.1905 0.4286 0 0 0 0 N 2

Figure I-3. Superstructure Transition Matrix 1999 to 2001

Superstructure Transition Matrix 1997 to 1999 Condition 9 8 7 6 5 4 3 2 q0 1 0 0 0 0 0 0 0 TX 1 1 32 23 6 4 1 1 TX-1 1 0 1 2 2 1 0 0 TX-TX-1 2 1 33 25 8 5 1 1 TX to TX 0.5 1 0.9697 0.92 0.75 0.8 1 1 TX to TX-1 0.5 0 0.0303 0.08 0.25 0.2 0 0 N 2

Figure I-4. Superstructure Transition Matrix 1997 to 1999

158

Substructure Transition Matrix 1999 to 2001 Condition 9 8 7 6 5 4 3 2 q0 1 0 0 0 0 0 0 0 TX 7 4 11 14 9 2 1 1 TX-1 0 2 6 2 0 0 0 0 TX-TX-1 7 6 17 16 9 2 1 1 TX to TX 1 0.6667 0.6471 0.875 1 1 0 1 TX to TX-1 0 0.3333 0.3529 0.125 0 0 0 0 N 2

Figure I-5. Substructure Transition Matrix 1999 to 2001

Substructure Transition Matrix 1997 to 1999

Condition 9 8 7 6 5 4 3 2 q0 1 0 0 0 0 0 0 0

TX 1 1 21 25 14 6 4 1

TX-1 1 0 0 2 2 0 0 0 TX-TX-1 2 1 21 27 16 6 4 1

TX to TX 0.5 1 1 0.9259 0.875 1 1 1 TX to TX-1 0.5 0 0 0.0741 0.125 0 0 0

N 2

Figure I-6. Substructure Transition Matrix 1997 to 1999

159

Channel Transition Matrix 1999 to 2001

Condition 9 8 7 6 5 4 3 2 q0 1 0 0 0 0 0 0 0 TX 1 12 21 36 19 3 1 1 TX-1 0 1 8 9 2 0 0 0 TX-TX-1 1 13 29 45 21 3 1 1 TX to TX 1 0.9231 0.7241 0.8 0.9048 1 0 1 TX to TX-1 0 0.0769 0.2759 0.2 0.0952 0 0 0 N 2

Figure I-7. Channel Transition Matrix 1999 to 2001

Channel Transition Matrix 1997 to 1999 Condition 9 8 7 6 5 4 3 2 q0 1 0 0 0 0 0 0 0 TX 0 1 23 42 30 9 1 1 TX-1 0 4 6 7 4 0 0 0 TX-TX-1 0 5 29 49 34 9 1 1 TX to TX 0 0.2 0.7931 0.8571 0.8824 1 1 1 TX to TX-1 0 0.8 0.2069 0.1429 0.1176 0 0 0 N 2

Figure I-8. Channel Transition Matrix 1997 to 1999

160

Appendix J Weighted Average Markov Probability Matrices

161

Deck Matrix 0.875 0.125 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0.8913 0.1087 0 0 0 0 0 0 0 0.8462 0.1538 0 0 0 0 0 0 0 0.8125 0.1875 0 0 0 0 0 0 0 0.8462 0.1538 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 Superstructure Matrix 0.8 0.2 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0.9074 0.0926 0 0 0 0 0 0 0 0.7949 0.2051 0 0 0 0 0 0 0 0.8 0.2 0 0 0 0 0 0 0 0.875 0.125 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1

Figure J-1. Weighted Deck and Superstructure Matrices

162

Substructure Matrix 0.8889 0.1111 0 0 0 0 0 0 0 0.7143 0.2857 0 0 0 0 0 0 0 0.8421 0.1579 0 0 0 0 0 0 0 0.9070 0.0930 0 0 0 0 0 0 0 0.92 0.08 0 0 0 0 0 0 0 1.00 0.000 0 0 0 0 0 0 0 0.8 0.2 0 0 0 0 0 0 0 1 Channel Matrix 1 0 0 0 0 0 0 0 0 0.7222 0.2778 0 0 0 0 0 0 0 0.7586 0.2414 0 0 0 0 0 0 0 0.8298 0.1702 0 0 0 0 0 0 0 0.8909 0.1091 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0.5 0.5 0 0 0 0 0 0 0 1

Figure J-2. Weighted Substructure and Channel Matrices

163

Appendix K Projected 20-Year Condition Rating Matrices

164

Deck Probability Matrix and 20-year Projection

P deck

.875

0

0

0

0

0

0

0

.125

.9999

0

0

0

0

0

0

0

0.0001

.8913

0

0

0

0

0

0

0

.1087

.8462

0

0

0

0

0

0

0

.1538

.8125

0

0

0

0

0

0

0

.1875

.8462

0

0

0

0

0

0

0

.1538

.9999

0

0

0

0

0

0

0

0.0001

1

q 0 1 0 0 0 0 0 0 0( )

n 20

q 20deck q 0 P deckn.

Figure K-1. Projected 20-Year Deck Condition Rating Matrix

165

Figure K-2.

Projected 20-Year Superstructure Rating Matrix

Superstructure Probability Matrix and 20-year Projection

P super

.8

0

0

0

0

0

0

0

.2

.9999

0

0

0

0

0

0

0

.0001

.9074

0

0

0

0

0

0

0

.0926

.7949

0

0

0

0

0

0

0

.2051

.8

0

0

0

0

0

0

0

.2

.875

0

0

0

0

0

0

0

.125

.9999

0

0

0

0

0

0

0

.0001

1

q 0 1 0 0 0 0 0 0 0( )=

n 20=

q 20super q 0 P supern.

q 20super 0.012 0.987 8.019 10 4. 2.856 10 4. 2.012 10 4. 1.451 10 4. 7.094 10 5. 1.949 10 8.=

166

Substructure Probability Matrix and 20-year Projection

P sub

.8889

0

0

0

0

0

0

0

.1111

.7143

0

0

0

0

0

0

0

.2857

.8421

0

0

0

0

0

0

0

.1579

.9070

0

0

0

0

0

0

0

.0930

.92

0

0

0

0

0

0

0

.08

.9999

0

0

0

0

0

0

0

.0001

.8

0

0

0

0

0

0

0

.2

1

q 0. 0 0 0 1 0 0 0 0( )

n 20=

q 20sub q 0. P subn.

q 20sub 0 0 0 0.142 0.334 0.523 1.881 10 4. 2.345 10 4.=

Figure K-3. Projected 20-Year Substructure Condition Rating Matrix

167

Channel Probability Matrix and 20-year Projection

P channel

.9999

0

0

0

0

0

0

0

.0001

.7222

0

0

0

0

0

0

0

.2778

.7586

0

0

0

0

0

0

0

.2414

.8298

0

0

0

0

0

0

0

.1702

.8909

0

0

0

0

0

0

0

.1091

.9999

0

0

0

0

0

0

0

.0001

.5

0

0

0

0

0

0

0

.5

1

q 0 1 0 0 0 0 0 0 0( )=

n 20=

q 20channel q 0 P channeln.

q 20channel 0.998 3.588 10 4. 4.052 10 4. 4.974 10 4. 4.528 10 4. 2.837 10 4. 4.027 10 8. 6.432 10 8.=

Figure K-4. Projected 20-Year Channel Condition Rating Matrix