rigid pavement design deficiencies major shortcomings of jpcp designs based on 1972-1986 versions of...

Rigid Pavement Design Deficiencies

• Major shortcomings of JPCP designs based on 1972-1986 versions of the AASHTO Guide :– inadequate joint load transfer, – long joint spacing, – erosion of base/subbase, – poor subdrainage– etc.

• Deterioration occurs early• Rehabilitation needed

Development of Supplemental AASHTO Design Procedure for

JPCP

• Serious deficiencies noted in 1986 AASHTO procedure

• Studies showed major flaws in base/subgrade support procedures

• No easy fixes• Improved structural (3D finite

element) model for JPCP was developed to correct deficiencies

Development, Validation, Adoption:

1998 Supplemental Rigid Pavement Design Procedure

• Developed under NCHRP Project 1-30 (University of Illinois at Urbana-Champaign)

• Validated under FHWA/LTPP research study (ERES Consultants/ARA) • Adopted by AASHTO as Supplementary Rigid Pavement Design

Procedure (1998)• FHWA/LTPP - Supplementary Rigid Pavement Design

Spreadsheet (ERES Consultants/ARA)

Only JPCP For Now

Jointed plain Jointed plain concrete pavementconcrete pavement

(JPCP)(JPCP)

• Most constructed rigidMost constructed rigidpavementpavement

• Basic design procedure Basic design procedure developeddeveloped

• Procedure field verifiedProcedure field verified

Jointed reinforcedJointed reinforcedconcrete pavementconcrete pavement

(JRCP)(JRCP)Continuously reinforcedContinuously reinforced

concrete pavementconcrete pavement(CRCP)(CRCP)

• Limited field verificationLimited field verification

1998 AASHTO JPCP Design Is Better

• Improved structural modeling• Improved subgrade characterization• Base course as structural layer• Transverse joint spacing• Climate at site is considered directly• Shoulder type and slab width• Joint faulting and cracking checks

Use of LTPP Data to Verify1998 AASHTO Design

• Design procedure verified using field data from LTPP

• Inputs to 1998 AASHTO design model obtained

• Actual traffic log ESALs compared to predicted log W (ESALs)

• No significant bias found in predicting serviceability of pavements in four climatic zones

PRESENTATION OBJECTIVES

• What is the Rigid Pavement Design (RPD) Software?

• Development of RPD Software• RPD Software Features and

Capabilities • How To Use The RPD Software • Who Should Use the RPD Software and Why• How to Get the RPD Software

Rigid Pavement Design Spreadsheet: Features

I. Input Sheet - General Information

The general information section requests information about the agency. This information is not required for the analysis, but the information entered here may be displayed on the "Results" sheet.

II. Input Sheet - Design Information

All design inputs are required except sensitivity analysis.No default values are used.

Information can be retrieved from the "Saved Data" sheet using the "Retrieve Data"button. The existing data can be replaced or saved as a new set using the"Save Data" button. Clicking on the "Retrieve Data" button opens the "Saved Data" sheet. Select theappropriate row to be retrieved and click on the "Export" button.If the retrieval is successful, the data are retreived. Changes can be made and savedas a new data set using a different value for the search ID. The data can also

Information sheet containing spreadsheet “User Guide”


Command buttons for easy navigation between sheets


Command button links to reference tables

Joint spacing and edge support conditions are direct inputs


Climatic properties are direct inputs in the supplemental rigid pavement design


True subgrade k-value is used (not adjusted for top-of-base)


Easy links to sensitivity analysis for various design inputs


Project data can be saved in rows and exported to the main sheets


Sensitivity Analysis plot displays inputs held constant


Results

Project #1-20-98LCBDescription: Lean Concrete Base, 5-in.

Location: Champaign, IL

Slab Thickness Design

Pavement Type JPCP18-kip ESALs Over Initial Performance Period (million) 21.88 millionInitial Serviceability 4.5Terminal Serviceability 2.528-day Mean PCC Modulus of Rupture 700 psiElastic Modulus of Slab 4,500,000 psiElastic Modulus of Base 25,000 psiBase Thickness 6.0 in.

Results sheet can be viewed on screen or can be printed


D Design Traffic L E l F(in) MESALs in in

7.0 1.32 180 1.00 29.88 1.10

7.5 1.92 180 1.00 31.47 1.10

8.0 2.76 180 1.00 33.03 1.09

8.5 3.92 180 1.00 34.57 1.08

9.0 5.51 180 1.00 36.08 1.08

9.5 7.65 180 1.00 37.58 1.07

10.0 10.50 180 1.00 39.05 1.07

10.5 14.25 180 1.00 40.50 1.06

11.0 19.11 180 1.00 41.94 1.05

11.5 25.35 180 1.00 43.36 1.05

12.0 33.29 180 1.00 44.77 1.04

12.5 43.30 180 1.00 46.16 1.03

13.0 55.83 180 1.00 47.54 1.03

13.5 71.37 180 1.00 48.91 1.02

14.0 90.51 180 1.00 50.26 1.02

14.5 113.94 180 1.00 51.60 1.01

15.0 142.42 180 1.00 52.93 1.00

11.00 19.11 180 1.00 41.94 1.05

11.24 21.91 180 1.00 42.63 1.05

Calculation sheet shows all calculations and displays design traffic for different slab thicknesses


Faulting Check sheet used to estimate faulting over design life for doweled and nondoweled pavements



• Development of the RPD Software• RPD Software Features and Capabilities • How To Use The RPD Software • Who Should Use the RPD Software and

Why• How to Get the RPD Software

Systems Requirements

• IBM PC running:Microsoft Office 95 or 97 or

Microsoft Excel 7.0

Using The RPD Software

• Copy the Rigid Pavement Design (RPD) Software spreadsheet to the hard drive

• The RPD software cannot be run from the floppy drive

• Open the RPD spreadsheet using Microsoft Excel


Click on Enable Macros to allow execution of spreadsheet macros

Using The RPD SoftwareClick on Input Form to access the main sheet

Using The RPD SoftwareEnter General Information for the project as shown below:


Scroll down to enter Serviceability and PCC Properties


Enter Base Properties, Reliability, and Standard Deviation

Click on Table 14 for friction factors for different base types

Using The RPD SoftwareClick on Input Form to navigate back to the main screen


Select Pavement Type and Edge Support Condition

Enter Joint Spacing

Using The RPD SoftwareEnter Climatic Properties for the design region. Click on Table 15 for climatic properties for major metropolitan areas in each State.

For the first run enter the approximate subgrade k-value


Click on Calculate Traffic for traffic calculation worksheet

Using The RPD SoftwareAfter entering traffic design inputs click Calculate

Click Export to Input Form

Using The RPD SoftwareClick on Calculate on the main sheet to calculate thickness for design inputs

Click on Calculate Seasonal k-Value for calculating seasonally adjusted k-value


Enter number of months and subgrade k-value for each season. Click Calculate.

Using The RPD SoftwareUse the chart to estimate adjusted k-value for fill layer above the subgrade and/or rigid layer beneath the subgrade

Using The RPD SoftwareClick on Calculate on the main sheet to recalculate thickness for design inputs with the adjusted k-value


Enter thickness for sensitivity analysis

Click Slab Thickness Sensitivity for sensitivity analysis of design traffic to slab thickness

Click on radial buttons for sensitivity analysis of design traffic to different design inputs

Using The RPD SoftwareClick on Faulting Check to perform checks for doweled and nondoweled faulting


Enter dowel diameter and other design inputs for doweled pavements

Using The RPD SoftwareClick on FI Table or Drainage Coeff. Table for tables containing information regarding these inputs

Click Calculate to obtain estimated faulting at end of design life

Click Results to view and print results


Enter design inputs for nondoweled faulting check and click Calculate

Click Corner Break Check to perform top-down cracking analysis


The critical values for joint faulting can be changed by entering the appropriate values below


On the Corner Break Check worksheet enter the built-in temperature gradient related to construction curling and moisture gradient

Using The RPD SoftwareUse one of six charts provided to estimate tensile stress at top of slab from total effective negative temperature differential

Using The RPD SoftwareThe tensile stress at the top of the slab is less than the bottom up tensile stress for which the pavement is designed

Using The RPD SoftwareResults sheet can be viewed on screen or can be printed

Click Save Data to save the design information entered


Enter ID for saving data and click OK


All design information is saved in rows with the first column corresponding to the data set ID

Select appropriate row and click Export to export design information from this sheet to main sheet. This sheet can be accessed by clicking on Retrieve Data on the main sheet.



• Development of the RPD Software• RPD Software Features and Capabilities • How To Use The RPD Software • Who Should Use the RPD Software &


Users of the RPD Software

• State and Provincial Highway Engineers

• Consulting Engineers

Benefits of Rigid Pavement Design

Software• Provides key answers not previously

addressed:– How do I adequately characterize the

subgrade support?– What is the best base type for the

conditions?– What is the optimum joint spacing?– Will this pavement fault or have corner

breaks?



• Development of the RPD Software• RPD Software Features and Capabilities • How To Use The RPD Software • Who Should Use the RPD Software &


Get & Use The Software

• Order software:

-- Through LTPP homepage

www.tfhrc.gov

-- Through LTPP customer

service

Call 865-481-2967

rigid pavement design deficiencies major shortcomings of jpcp designs based on 1972-1986 versions of...

Documents

design traffic

design life

aashto guide

aashto procedurestudies

field data

featuresinformation

featurescalculation

featuresresults sheet