FHWA BRIDGE PRESERVATION PDATEFHWA BRIDGE PRESERVATION UPDATE KSU 25 th Annual Bridge Design Workshop Kansas State University Alumni Center October 5, 2018 Anwar Ahmad, P.E. Structures
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FHWA BRIDGE PRESERVATION UPDATE KSU 25 th Annual Bridge Design Workshop Kansas State University Alumni Center October 5, 2018 Anwar Ahmad, P.E. Structures Team Manager FHWA Resource Center [email protected]
As per 2017 NBI Data- Total # of bridges – 615,002 Good bridges are shown in Green, which is 9, 8 and 7 as per the NBI rating; Fair bridges are shown in Yellow, which is 6 and 5; and Poor bridges are shown in Red, that are 4 and below.
As per 2017 NBI Data- Total # of bridges – 615,002 Good bridges are shown in Green, which is 9, 8 and 7 as per the NBI rating; Fair bridges are shown in Yellow, which is 6 and 5; and Poor bridges are shown in Red, that are 4 and below. While we have done a good job of reducing the poor bridges as shown in red, the number of fair bridges, shown in yellow, are increasing. These are all the candidates for Bridge Preservation!
NATIONAL INITIATIVES:FHWA BRIDGE PRESERVATION GUIDE – UPDATED SPRING 2018
• Identifies cyclical and condition-based preventive maintenance activities.
• Defines routine maintenance and activities not eligible for Federal funds.
• How to establish a bridge preservation program.
www.fhwa.dot.gov/bridge/preservation/
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Background Information: The original guide was published by FHWA in August, 2011, when SAFETEA-LU was in effect and bridge repair and rehabilitation activities were funded by the Highway Bridge Program. This guide identified a "systematic process" as an eligibility of PM actions for Federal aid funds. As a result, several Divisions have signed agreements with their states as part of the stewardship and oversight agreements. Activities are not consistent among the Divisions. MAP21 allowed preservation activities to be eligible and there was a need to update the guidance and come up with a comprehensive list of PM activities for consistency throughout the country. Also, routine maintenance was never defined for bridges and what activities qualify as routine that are not eligible for Federal funds. The new guide provides those example activities as well. In addition it provides guidance on how to establish a bridge preservation program if an agency desires to build one. With the enactment of MAP-21 and now FAST-Act, the Highway Bridge Program was replaced by the National Highway Performance Program and Surface Transportation Block Grant Program. These two programs now allow bridge preservation activities to be eligible for Federal funds. As a result, FHWA issued a guidance on bridge preservation on February 25, 2016. And now, on April 28, 2018, we released a new Bridge Preservation Guide. This guide: Identifies cyclical and condition-based preventive maintenance activities for consistency throughout the nation Defines routine maintenance and identify examples of routine maintenance activities not eligible for Federal funds; and Provides guidance on how to establish a bridge preservation program Each Division and Federal Lands should have received three (3) copies to share with their state and Federal partners. If not, then please reach out to Raj Ailaney in the Office of Bridges and Structures.
• Vision:– Bridge preservation today….for a better transportation infrastructure
tomorrow• Mission:
– Advance and improve the state of the practice in the area of highway bridge preservation by working collaboratively with Federal, State and local agencies, professional associations (AASHTO, TRB), industry, and academic interests
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The Bridge Preservation Expert Task Group is chaired by Raj Ailaney of Office of Bridges and Structures. FHWA formed a Bridge Preservation Expert Task Group in 2009/2010. the group comprised of bridge preservation practitioners from State DOTs, Industry, Academia, and FHWA. The mission of the group is to advance and improve the state of the practice in the area of highway bridge preservation by working collaboratively with federal, state and local agencies, industry, and academic interests. The group’s vision is “Bridge preservation today….for a better transportation infrastructure tomorrow” and their mission is to “advance and improve the state of the practice in the area of highway bridge preservation by working collaboratively with Federal, State and local agencies, professional associations (AASHTO, TRB), industry, and academic interests”. You can get more information on the makeup of the group and their strategic plan on the FHWA’s bridge preservation website shown in this link.
Strategic Goals1. Provide guidance on cost-effective bridge preservation
strategies2. Promote bridge preservation as a component of asset and
performance management3. Advise and assist in developing educational materials on
bridge preservation4. Foster a collaborative environment that encourages
research and innovation
www.fhwa.dot.gov/bridge/preservation/
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strategic plan has four goals. Under each of these goals and strategic objectives, they have several action items. I’ll give a brief update on few of them.
Developing a series of Pocket Guides that will provide a focus on construction quality. Some of the topics that are currently being developed are: Thin Polymer Overlay Systems– lead by Gregg Freeman; Bridge Joint Systems – lead by Debbie Steiger; Bridge Cleaning – lead by Dr. Mike Brown; Bridge Coatings – lead by Ted Hopwood and Paul Vinney They are designed to address common errors and best practices to aid in preventing failures related to proper selection and application procedures. They are expected to: provide proper installation/repair guidelines; provide a check-list for equipment and tools needed; identify limitations and restrictions including regional climates, traffic, and storage; and, identify potential failure mechanisms and how to avoid them. These guides will be electronic and will also be accessible via iOS and Android App.
• Contract awarded in September 2017 to the University of Colorado – Period of Performance – 18 months– Task 1 – Literature review of three state agencies of preservation
actions– Task 2 – Develop a methodology for agency rules that is flexible
and adaptable to owner/agency’s existing BMS– Task 3 – Develop an analytical tool based on the methodology– Task 4 – FHWA TechBrief– Task 5 – Webinar– Task 6 – Final Report
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Last fall, FHWA awarded a contract to the University of Colorado to develop a decision methodology that will help in answering that question. Under this contract, we have six tasks. The PI is currently finishing up Task 2. We hope to have a tech brief issued soon, followed by a webinar. The analytical tool will be on a spreadsheet that each agency can modify based on their needs. Also, this project will supplement the ongoing research, NCHRP 14-36 Guidelines for Preservation Decision Making for Existing Bridges.
• Iowa DOT – Lead– Develop and Issue RFP – Late 2018– Period of Performance – 1 Year
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This project has initiated from an original idea of developing a Transportation Asset Preservation Portal. The goal is to establish a web portal for repository of proven preservation actions to maintain bridges in good and fair condition. After discussions with BPETG members, it was decided to first develop a proof of concept focusing on concrete decks. This will be organized by component defect, cause, feasible actions, and cost information. FHWA is supporting the development and Iowa DOT is leading the project. They have formed a Technical Advisory Committee to lead this effort. They plan to issue the RFP within couple of months, select a contractor and complete the project by next fall. The outcome of this project will be rolled into a pooled-fund project to develop the Transportation Asset Preservation Portal.
• NCHRP 12-108, Guide Specifications for Service Life Design of Bridges– Objective – Provide bridge owners and designers with specifications
for designing a bridge for a specific service life– Deliverable
• Report documenting service life design research effort• Guide Specifications• Design Examples
– Schedule• Final Deliverable – February 2019• Ballot Item at COBS 2019 Annual Meeting
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• NCHRP 14-36, Guidelines for Preservation Decision Making for Existing Bridges– Objective: Provide bridge owners and designers with guidelines for
preservation decision making for existing bridges– Deliverable
• Report documenting bridge preservation decision making research effort, and specifically for bridge decks
– Schedule• Final Deliverable – November 2018 for bridges in general, September 2019 for
bridge decks• Draft Guideline for Bridge Preservation Ballot Item at COBS 2019 Annual Meeting• Draft Guidelines for Bridge Deck Preservation Ballot Item at COBS 2020 Annual
Meeting
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• Guide Specifications for Bridge Strengthening with Titanium– Objective – Develop AASHTO guide specifications for titanium
strengthening of bridges (OR Lead State with Support from VA)– Deliverable
• Report documenting research findings• Draft AASHTO Guide Specification for Titanium Strengthening of Bridges
– Schedule• Final Deliverable – January 2019• Ballot Item at CBS 2019 Annual Meeting
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• Guide Specifications for Preservation of Historic Bridges– Objective – Develop AASHTO guide specifications for preserving
historic bridges (OR Lead State)– Deliverable
• Report documenting research findings• Draft AASHTO Guide Specification for Preservation of Historic Bridges
– Schedule• Final Deliverable – February 2019• Coordinate with Committee on Environment, National Park Service• Ballot Item at CBS 2019 Annual Meeting
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• TSP-2 = Technical Services Program, Transportation System Preservation
• Bridge preservation program approved by AASHTO BOD 2005• Contract with NCPP (University of Michigan) executed 2006• Funded through voluntary State contributions of $20,000 per year• Four regional partnerships have been established since 2010
(Southeast; Northeast; Mid West; West)
https://tsp2bridge.pavementpreservation.org/
• BMS Working GroupCo-Chairs: Dan Muller, NCDOT; Dave Juntunen, Kercher Group
• Industry Technology Demonstration Program (ITD)Chair: Ed Welch, National Center for Pavement Preservation
• National Bridge Preservation Social MediaChair: Lorella Angelini, Angelini Consulting Services, LLC
• National Bridge Deck PreservationChair: Becky Nix, UT DOT
• National Bridge Preservation CoatingsChair: Jeff Pouliotte, FL DOT
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AASHTO TSP-2 has several national and regional working groups. This is a current list of the National Working groups.
• Recently Completed Research– Guidelines for Maintaining Small Movement Bridge Expansion Joints
– NCHRP 12-100– Assessing, Coding, and Marking of Highway Bridge in Emergency
Situations – NCHRP 14-29– Spot Painting to Extend Highway Bridge Coating Life – NCHRP 14-30– Identifying Bridge Maintenance and Preservation Activities which
Minimize Environmental Impact – NCHRP 20-07/Task 399• Funded Research
– Effective Use of Duplex Coating Systems to Improve Steel Bridge Structure Durability – NCHRP 12-117
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CURRENT FHWA NDE RESEARCH PROJECTS• Robotic air-coupled acoustic array • Magnetic flux leakage system for pre-stressed girders• Magnetic main flux system for internal post-tensioned tendons• Protocols for reproducing defects in concrete laboratory
structures• NDE of Bridge Decks with Overlay• Phased Array Ultrasonic Testing (PAUT)• Effectiveness and accuracy of Fiber Optic Sensors bridge weigh-
in-motion systems• NDE Web Manual• Unmanned Aerial Vehicle (UAV): Bridge Inspection - Data
Quality and Handling• Leveraging Augmented Reality for Highway Construction
• The MFL NDE system is being designed to scan the length of prestressed concrete I-girders in highway bridges and detect corrosion in the prestressing steel.
• The system contains two primary sub-systems, the magnets/sensors assembly and the robotic rover frame.
Payload
Payload ReceiverRobotic Rover
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The MFL is the most effective NDE tool that can detect and approximately quantify the extent of corrosion or fracture of prestressing steel in concrete. Under the NDE contract, an advanced state-of-the-art magnetic flux leakage (MFL) system is currently being developed by the investigators at the Technology Research Institute (TRI) and the University of Wisconsin-Milwaukee. The current project is focused on the application of the MFL on AASHTO concrete girders. The MFL system being developed consists of two strong permanent magnets and 64 Hall-effect sensors that measure vertical and longitudinal magnetic field variations caused by corrosion or fracture of prestressing steel in I-girders. Depending on the extent of the ferromagnetic materials that may be present in a girder, i.e., shear stirrups and non-structural steel like chairs, the MFL system will be able to detect corrosion as small as 1% of the cross section of the strands being tested. Under the current project, the investigators are developing a robotic carrier unit that transports the MFL device along the length of the I-girders. The robotic carrier unit is capable of negotiating around the transverse diaphragms that may be present in prestressed concrete I-girder bridges. The articulating legs are equipped with various motors, gears, and control devices that allow installation, operation, and removal of the rover on and from concrete I-girders.
• Inspection of PT tendons imposes the greatest challenge.
• An earlier FHWA NDE study found that Magnetic Main Flux Method (MMFM) worked well for external PT tendons.
• developing prototypes for internal tendons and anchorage zones using yoke type MMFM systems.
The first MMFM prototype on an internal mock-up tendon
MMFM for external tendons
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Internal tendons are discovered frequently to contain grout voids which are high risk areas of future corrosion Anchorage zones are challenging areas due to massive concrete and presence of densely placed reinforcements It has been recognized that reliable inspection of PT tendons, especially internal tendons and anchorage zones, is the most critical and challenging topic for bridge owners and maintenance engineers. After experiencing a tendon failure in Varina-Enon Bridge in 2007, FHWA carried out an in-house study from 2008 to 2015 to explore various NDE technologies for locating and estimating corrosion damage in bonded external PT tendons. It was determined that Magnetic Main Flux Method (MMFM) was the most accurate NDE technology for the external tendons. Specifically, the solenoid type and permanent magnet type MMFM systems could measure strand section loss as low as 0.4% and 1.5%, respectively. Based on the encouraging outcomes of the first study, the second NDE study was launched in January 2017 to develop a prototype for internal PT tendons and another one for anchorage zones. These prototypes employ the same principle of solenoid type MMFM system, but their magnetizers utilize a yoke type configuration with return flux measurement capability in order to provide sufficient magnetic strength to reach internal tendons through thick concrete cover. At the end of this study, we will know whether magnetic based NDE technology will work for these critical components or not.
• Objectives– Finished laboratory validation of
nine NDE technologies on concrete specimens with seven types of overlays
– Will perform field validation of nine NDE technologies on in-service bridges
Rebar cage and artificial defects
Ultrasonic scanning with KUKA robotic arm Placing overlay on concrete specimen
debonding
specimenoverlay
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Overlay systems have been used since 1960 to extend the service life of deteriorated concrete decks. The ultimate goal of this study is to identify and describe the effective and promising NDE techniques that can assess the performance of concrete bridge decks with overlays, and detect and characterize deterioration in decks and overlays. This study uses various NDE techniques (infrared thermography, ground penetrating radar, electrical resistivity, half-cell potential, impact echo, ultrasound surface wave, ultrasonic shear wave tomography, impulse response and sounding) to evaluate small-scale specimens in the laboratory with artificial defects and real bridges in the field under actual conditions.
Objectives:• Evaluate the effectiveness and accuracy of fiber optic shear sensors as a BWIM
technology on in-service bridges.• Evaluate capabilities with respect to providing repeatable, research-quality
measurements of axle weight and spacing, vehicle speed, and identification of vehicle classification.
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In the lower left corner, Figs. 1-4 shows the BWIM system, which involved fiber optic shear rosettes for measurement of axle weights, wheel sensors for detection of number of axles, and additional sensors for the computation of axle spacings and speeds in each lane. Figs. 1 provides views of the Nema enclosure with the fiber optic interrogation unit and local computer, and cellular wireless. Fig 2 shows the shear rosette sensors. Fig 3 shows wheel sensors. Fig 4 shows proximity of shear and rosettes sensors in protective steel box enclosures following the installations. People can remotely access the computer installed at the bridge location. The BWIM program is shown in figs 5 - 8. Fig 5 shows the “Sensors” tab, alternate sensors can be selected for use in the BWIM algorithm if needed (Changes to this tab should be done by trained personnel.). Fig 6 shows the “Signals” tab, one may select the desired lane from the drop down menu in the lower left corner, thresholds can be adjusted and maintained in order to differentiate genuine peaks from signal noise. Fig 7 shows the “Results Table” tab, the most recent results can be viewed. As shown in fig 8, past results are stored in text files on the remote hard drive, and each file contains the calculated results data from one hour of traffic in each lane. Fig 9 shows the calibration and validation of the BWIM system on the I-84 Bridge. The calibration process took place over a four-day period. Two class 9 trucks per ASTM standards were employed for the calibration of the BWIM system. A total of 40 truck passes were recorded and used for calibration. Thirty two (32) runs were made in the right lane, for which, 6 used for calibration and 26 used for verification. Eight (8) runs were made in the left lane, 2 used for calibration and 6 used for verification. The calibration and verification runs were successful in providing the appropriate calibration factors for the individual traffic lanes, and the detection of the truck weights in motion with minimal errors.
• Document state of sensors being deployed on UAV for bridge inspection;
• Assess the quality level of data needed for satisfactory inspection;
• Document types of performance information given to the owners;
• Provide guidance on how the collected data should be assessed, presented, and stored
• Create best practice guidelines.
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Project will focus on how data is collected and the quality of data needed. An outcome of the project will be to provide guidance on how the collected UAS data should be assessed, presented, and stored to give actionable and intelligent information to bridge owners and to support data-driven decisions. It builds off of an ongoing FHWA project that is documenting how UASs are being used for highway applications. Much of the current UAS use is for bridge inspections. Unmanned Aerial Systems(UAS): Data Quality and Handling for Highway Applications Objective: Assess the data quality that can be obtained from current generation UAS and compare it to the quality needed for effective highway applications such as bridge inspections. Identify how UAS data is being managed and stored and made accessible. Identify gaps in data quality and storage and provide guidance and best practices.
Objectives:• Provide concise and unbiased
guidance to help practitioners identify the NDE technologies that can serve their specific need.
https://fhwaapps.fhwa.dot.gov/ndep
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The Bridge Module is completed The modules for pavement and tunnel structures is under development. Two examples are presented. In the upper left, the path for finding NDE technology for asphalt pavement segregation is provided. In the upper right, the webpage of the selected NDE technology (Infrared thermography) is presented. In the lower left, the path for finding NDE technology for detecting corrosion of steel roof girder in a tunnel is provided. In the lower right, the webpage of the selected NDE technology (Phased array ultrasonic testing) is presented.
Bridges and Structures:Anwar Ahmad, P.E.Federal Highway AdministrationResource [email protected]
Bridge Preservation:Raj Ailaney, P.E.Federal Highway AdministrationOffice of Bridges and [email protected]
NDE Research & Technologies: Hoda Azari, Ph.D.Federal Highway AdministrationTurner-Fairbank Highway Research [email protected]
