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500 Fifth Street, NW, Washington, DC 20001 Phone 202.334.2936 Fax 202.334.2920 E-mail firstname.lastname@example.org www.TRB.org January 30, 2019 Brandye Hendrickson Deputy Administrator Federal Highway Administration 1200 New Jersey Avenue, SE Washington, DC Dear Deputy Administrator Hendrickson, The committee for the Review of Federal Highway Administration (FHWA) Infrastructure R&D Program met November 29â30, 2018, in Washington, D.C., to review and discuss the progress of the Long-Term Infrastructure Program (LTIP). The committee members and FHWA staff who attended the meeting are listed in Attachment A. The charge to the committee is to âadvise the Federal Highway Administration (FHWA) Infrastructure R&D Program regarding priorities in terms of the technical tools and products that state departments of transportation need to maintain and improve the performance of their pavements, bridges, and other structures.â The committee was established to provide an ongoing review of the LTIP based on annual meetings with FHWA staff and stakeholders. The first day of the meeting was structured around brief updates on program progress on the two components of the LTIP: the Long-Term Pavement Performance (LTPP) program and the Long- Term Bridge Performance (LTBP) program. The meeting agenda appears in Attachment B. Each agenda item provided ample time for the committeeâs questions and discussion. On the second day of the meeting, the committee held a closed session to develop its recommendations. It finalized its recommendations and this letter report through correspondence. The letter report provides an overview of the LTIP, accomplishments in the past year, strategic issues for the future of the program, and the committeeâs findings and recommendations for strengthening the LTIP effort. On behalf of the committee, I would like to thank Hari Kalla, Cheryl Richter, Jean Nehme, and the entire FHWA staff in attendance for a constructive set of updates and discussions. We appreciate the attendance of Joey Hartmann, Director of FHWAâs Office of Bridges and Structures, and Brian Fouch, Director of FHWAâs Office of Preconstruction, Construction, and Pavements at the meeting. We also wish to commend the LTIP staff on the substantial progress made in 2018 as described later in this report. CONTEXT The committeeâs review of the LTIP is undertaken in the context of the asset management requirements established by Congress in the Moving Ahead for Progress in the 21st Century (MAP- 21) Act of 2012.1 Also relevant are MAP-21âs requirements, as amended in the Fixing Americaâs Surface Transportation System (FAST) Act of 2015, that states set performance goals for the National Highway System (NHS) routes within their states, including for measuring and maintaining 1 See Asset Management Guidance Questions and Answers at https://www.fhwa.dot.gov/asset/guidance/faqs.cfm.
2 the condition of NHS assets.2 Implementing regulations for asset management are codified in 23 CFR Part 515. Many state departments of transportation (DOTs) were engaged in asset management before MAP-21 in order to stretch their limited resources to extend the life and performance of highway assets at the lowest cost. By requiring all states to develop Transportation Asset Management Plans by 2018, MAP-21 has formalized and made more consistent the practice of asset management across the country. Asset management and performance management requirements have heightened asset ownersâ interest in finding and implementing better ways of measuring, monitoring, and predicting the life-cycle performance of pavements and bridges. A successful program of asset management will extend the life of assets and minimize expenditures. Measuring and monitoring conditions provide a baseline for planning and indicators of how well asset management practices are performing over time. Measuring and monitoring the performance of pavements and bridges are essential for predicting future conditions and developing the most cost-effective, long-term strategies for asset maintenance, repair, rehabilitation, or replacement. The asset management plans required under 23 CFR Part 515 depend on forecasts of future asset performance. Models that predict asset deterioration, which in turn permit treatments to be applied at the optimal point to reduce life-cycle costs, are critical linchpins in asset and performance management planning. The pavement condition and performance data collected over the course of more than 25 years through the LTPP program component of the LTIP have been valuable for developing pavement deterioration models that account for the wide variety of pavement materials, designs, traffic levels, subsurfaces, and climate conditions that exist in the United States. In contrast, deterioration models for bridges and their components are far less well developed, in part because of the lack of condition and performance data for calibrating and validating such models. Bridge inspection data based largely on visual inspection have been collected since the early 1970s, but such data suffer from the inability of inspectors to see early-stage corrosion on reinforcing steel embedded in bridge decks, superstructures, and substructures. The LTBP program is just beginning to collect non-destructive evaluation (NDE) field performance data on untreated concrete bridge decks (bare decks without asphalt overlays or other surface treatments to minimize the corrosion of reinforcing steel within the decks). Untreated concrete decks are but one of the six prioritized bridge components that the LTBP is designed to initially address. The committeeâs emphasis on the LTBP in this letter report is driven by the dearth of data for developing and refining the models needed to guide and optimize bridge asset management. State DOTs must make decisions today about how to allocate resources in compliance with federal asset and performance management planning requirements. Models exist for predicting bridge deck performance, including those contained in commercial asset management software packages and those developed for some individual state DOTs, but inadequate data are available for the calibration and validation necessary for improving the utility of existing models and for developing better ones.3 As described later in this report, the LTIPâs strategy for bridge condition and performance data collection through the LTBP program needs to account for the immediate need for data and models to predict bridge component performance as well as the collection of data over the long term to improve the capability of such models. 2 See Transportation Performance and Management Statutes and Regulations at https://www.fhwa.dot.gov/tpm/about/how.cfm. 3 Nickless, K., and R. Atadero. 2018. Mechanistic Deterioration Modeling for Bridge Design and Management. ASCE Journal of Bridge Engineering, Vol. 23, Issue 5. See also Moomen, M., et al. 2016. Bridge Deterioration Models to Support Indianaâs Bridge Management System. Joint Transportation Research Program Publication No. FHWA/IN/JTRP- 2016/03. West Lafayette, Ind.: Purdue University. doi: http://dx.doi.org/10.5703/1288284316348.
3 OVERVIEW Long-Term Pavement Performance Conceived and initiated as part of the first Strategic Highway Research Program (SHRP) in 1987, the LTPP has been managed by FHWA since 1992. It is the worldâs largest ongoing experiment to explore the causes of pavement deterioration by taking into account the effects of climate and loads on pavements of differing designs and materials. Data collection categories are climate, traffic volumes and loads, pavement layer type and thickness, material properties, and pavement condition (distress, longitudinal and transverse profile, and structural evaluation). As a result of diminished funding over time, the programâs mission has been narrowed to focus mostly on data collection and storage, as well as some limited original data analysis. At its peak, the program was collecting data on more than 2,500 test sections in the United States and Canada.4 Today the program continues to collect data on 436 test sections. Data collection did not occur in 2017 while the LTPP program staff consolidated its data collection contractors from four to one in order to reduce costs. Critical to the utility of the LTPP has been the collection of accurate and consistent data characterizing pavement structures (layer thicknesses and materials), environmental conditions, traffic loads, and indicators of pavement condition. The LTPP developed a series of protocols for instrument calibration and data collection to ensure research-quality data, comprised of both physical data (cores taken of pavements) and electronic data on loads and climate conditions. Many state DOTs have adopted these protocols for their own pavement data collection. The enormous LTPP data set (just less than nine terabytes) is archived in the Cloud and served by several high-capacity servers. FHWA has made the data accessible to analysts and researchers through a website (InfoPaveâ¢) that provides readily defined and downloadable data sets. Long-Term Bridge Performance âThe LTBP Program is a [FHWA] long-term research effort to collect high-quality bridge data from a representative sample of highway bridges nationwide that will help the bridge community to better understand bridge performance.â5 The program was authorized in the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU), which was enacted in 2005.6 The data collection effort will focus on three common bridge designs: steel multi-girder, prestressed multi-girder, and prestressed/post-tensioned concrete box girder. The sample is made up of 14 clusters of bridges in multiple states that span various climactic zones and 10 major north-south and east-west Interstate Highway corridors. These bridges will be inspected using NDE methods as well as arms-length visual and tactile methods. FHWA collected âlegacyâ data, mainly from as-built construction plans but also including any available maintenance records, on almost 500 cluster bridges. The final sample size will depend on program resources. 4 Information about the LTPP program in the remainder of this section is summarized from briefings to the committee and FHWA. Long-Term Pavement Performance Program. Publication No. HWA-HRT-15-018 HRDI-30/12-14(1M)E. 5 FHWA. Long-Term Bridge Performance (LTBP) Program. Publication No: FHWA-HRT-18-008 HRDI-30/11- 17(1.5M)E. 6 Information provided in the remainder of this section is summarized from presentations made to the committee and the LTBP website. See https://www.fhwa.dot.gov/research/tfhrc/programs/infrastructure/structures/ltbp/index.cfm.
4 Based on consultations with state DOT bridge engineers, the LTBP program established six priority areas for data collection during the initial phase to address the most problematic bridge elements7: Untreated decks, Treated decks, Deck joints, Bearings, Coatings for steel superstructure elements, and Condition of embedded pretensioned strands and post-tensioned tendons. At present, the program is limited to the collection of data on untreated bridge decks. Bridge decks are an appropriate place to begin because deck maintenance, repair, and replacement represent such a large share of state DOT bridge capital and maintenance budgets. In order to improve on the limitations of common visual inspection, the program has sought to evaluate and use NDE and arms- length tactile measures to assess the interior corrosion of reinforcing steel and delamination as influenced by existing cracking or if initiated before cracks become manifest. Such data can help improve models predicting the optimal timing of deck maintenance and repair. Over the past several years, the LTBP has invested in the development of the RABIT-CEâ¢ bridge deck assessment tool, which combines five different techniques for collecting NDE data on bridge deck condition in a faster, more consistent, and efficient fashion than collecting these data separately. FHWA acquired several RABIT-CEsâ¢ to collect NDE data on bridge decks. The data collection was substantially delayed in 2018 while equipment validation and contract issues were being resolved. In order to ensure the consistency of the data collection, FHWA prepared 51 protocols for NDE data collection and more are in preparation. All of the data collected are being made available to analysts and researchers through a new FHWA portal, InfoBridgeâ¢. In addition to the field data collected through the LTBP, InfoBridgeâ¢ provides ready access to National Bridge Inventory (NBI) data, National Bridge Elements (NBE) data, traffic data, records of maintenance and preservation, and weather data. ACCOMPLISHMENTS The LTIP staff reported on several important accomplishments since the committee met in November 2017. We briefly list these accomplishments in this section and mention the importance of several of them in the sections that follow: 1. Development of a Strategic Plan for the LTIP; 2. Development of the beta version of the InfoBridgeâ¢ portal for accessing and evaluating NBI and NBE inspection data for all bridges and for accessing the limited NDE data collected to date on bridges in the LTBP sample; 3. Addition of MnROAD test track data to InfoPaveâ¢, which had been a long-term goal of the former LTPP committee; 4. Recent and planned outreach to American Association of State Highway and Transportation Officials committees and other stakeholders; 7 FHWA. 2014. Long-Term Bridge High Priority Bridge Performance Issues. U.S. Department of Transportation. FHWA-HRT-14-043. https://www.fhwa.dot.gov/publications/research/infrastructure/structures/ltbp/14043/index.cfm.
5 5. Production of, and plans for, improved communication, including a draft of a one-page brochure the committee requested, plans for semi-annual web meetings with this committeeâs expert task groups for pavements and bridges, and for quarterly one-page updates to this committee on program progress; 6. Validation of RABIT-CEâ¢ data collection using FHWA staff on bridges in Mississippi while working out contract issues with the LTBPâs data collection contractor; 7. Consolidation of LTPP contractors and the acquisition and deployment of transverse profile data collection vans for data collection by LTPP contractors; and 8. Addition of post-doctoral fellows to the LTIP staff to develop deterioration models. The committee is particularly pleased with the extent to which the LTIP staff have addressed the recommendations in its first letter report, particularly the development of a strategic plan and more concerted outreach, as well as the progress made during 2018 in both the LTPP and LTBP programs. NOTEWORTHY DISCUSSION ITEMS During the meeting, FHWA and the LTIP staff provided an update on most aspects of the LTBP and LTPP programs. This letter report does not comment on all of the items covered during the meeting, but highlights in this section five noteworthy items that arose during the discussion because of their relevance for both serving the immediate needs of developing deterioration models to guide asset management and the long-term data collection of in-field performance to help improve deterioration models. The LTIP Strategic Plan The development of a strategic plan in 2018 is an important accomplishment for the LTIP program. The plan contains appropriate vision and mission statements as well as near-term (four-year) objectives for data collection, management, and access; research; tool development; and outreach. The plan should help expedite and guide long-term data collection. Importantly, it includes the exploration of accelerated testing methods and the development of deterioration models. It would be desirable, however, for a future version of the plan to be more explicit about how the LTBP will address the five priority areas beyond collecting data on untreated decks. For example, NDE techniques being used on bare decks do not work on concrete decks with asphalt overlays, which is the most common form of deck surface treatment. This difference suggests that a data collection strategy for treated decks should focus on data relevant to assessing the timing and effectiveness of various types of overlay performance in protecting decks from cracking, corrosion, and delamination. To do this, the program could build on the accelerated lab testing experiment described in the next section. The committee is particularly mindful of the several years that were required to develop the NDE techniques and technology being applied for assessing bare decks. To the extent that the monitoring of other priority areas (treated decks, joints, bearings, coatings, and pre- and post- tensioned strands and tendons) will also need to rely on NDE techniques, it would be prudent to begin evaluating the relevant technologies and approaches. The committee recognizes that technology evaluations for NDE measurement approaches are already under way in FHWAâs NDE lab, as described during our most recent meeting.
6 Laboratory Testing FHWA staff described a new experiment that will test accelerated deterioration of a full-scale bridge superstructure over a two-year period at Rutgers Universityâs new Bridge Evaluation and Accelerated Structural Testing (BEASTÂ®) laboratory.8 This unique facility can apply heavy loads at an accelerated pace, vary temperatures from below freezing to more than 100 degrees Fahrenheit, and simulate freeze-thaw cycles, precipitation, and application of deicing chemicals. The LTBP, in collaboration with FHWAâs NDE lab, funded the experiment. At the time of the meeting, the complete scope of the effort had not been fully defined, but it will include testing bare decks, various surface treatments and overlays, and other superstructure elements. The experiment may run up to two years, depending on the time required to prematurely deteriorate bridge components to the desired level. The scope will also validate NDE measurements taken regularly over the course of the experiment. The data developed from this experiment will then be used to begin developing deterioration models for bare decks, various overlays and treatments, coatings, bearings, and joints. Committee members expressed great interest in this experiment because of its ability to compress the time required to create and measure deterioration under controlled conditions and to test the extension of deck service life through the application of different overlays and coatings. In addition to providing data for deterioration models more quickly than through the monitoring of in- field performance, this experiment could lead to the development of a mechanism to more rapidly evaluate the performance of the different kinds of deck treatments that state DOTs are interested in trying. The LTIP program managers would benefit from strategically examining the most efficient and cost-effective ways of assessing bridge component performance for the purpose of developing deterioration models, including evaluating which bridge components can only be effectively monitored for this purpose through long-term, in-field techniques and which can also rely on other approaches. Deterioration Models FHWA staff explained how post-doctoral fellows assigned to the LTBP program have started to develop deterioration models using NBI, NBE, and NDE data. The committee believes such model development and refinement using existing data, or data that can be collected through accelerated techniques, have the potential to benefit asset owners and managers in the near term. Interim Products Several of the accomplishments listed above are providing interim products that states and researchers can use today. Examples include the new InfoBridgeâ¢ data portal, inclusion of MnROAD test track data in InfoPaveâ¢, and NDE data collection protocols. Sustaining interest in supporting long-term experiments is a challenge, and may explain the declining levels of funding for the LTPP over time. The development of interim products can sustain policy makersâ interest in supporting the program while data are collected over a long time horizon. 8 See Bridge Evaluation and Accelerated Structural Testing at https://cait.rutgers.edu/facilities-equipment/the-beast.
7 State Data As mentioned above, the LTBP is collecting legacy state data for about 500 bridges in the LTBP sample, which the program requested from state DOTs a few years ago. FHWAâs contractor has coded the legacy data for entry into the LTBP database. Most of this information came from as-built plans. Some states also provided maintenance records or expenditure data on state bridges. Not all states could do so, depending on how their expenditure and maintenance records were coded and stored (to the extent to which they are digitized). Many states, however, are in the process of updating, improving, and digitizing their maintenance and expenditure records, which suggests that more legacy data may be available than when initially requested. If state DOTs are made aware of the benefits of having such additional data in the LTBP database, more of them may be inclined to takes steps to gather and format the data in the requisite manner when making ongoing improvements to their information systems. CONCLUSION Based on the development of an LTBP strategic plan, the large-scale accelerated testing experiment, and the addition of staff (post-doctoral fellows) with capabilities in deterioration modeling, the LTIP is displaying nimbleness in responding to the demands that exist today for asset management while continuing to collect long-term performance data. The development of interim products and improved outreach and communication described in the previous section will position the LTBP for the even greater agility the committee believes will be required in the future to sustain the program. FINDINGS AND RECOMMENDATIONS Finding 1: States need improved deterioration models to optimize resource allocation through asset management. Through the LTIP, FHWA is playing a valuable role in supporting this decision making by pursuing a nationwide, complex, and costly form of data gathering and research. State DOTs and other asset owners could not undertake such an effort as efficiently, either individually or collectively. Recommendation 1: FHWA should accelerate the collection of bridge deck performance data and ensure that LTIP plans and resources for data collection are aligned with the asset management and performance management requirements of MAP-21 and the FAST Act as well as the goals of FHWA program offices charged with helping state DOTs implement the requirements. Finding 2: The continued provision of interim products that confer benefits to states and other stakeholders in the near term will help sustain interest in supporting the LTIP while it continues to collect performance data over the long term. Improved access to NBI and NBE data through InfoBridgeâ¢ and the addition of MnROAD data to InfoPaveâ¢ are clear successes for the LTIP program in 2018. In light of the new condition performance requirements in law and regulation, the completion and sharing of LTBP NDE data collection protocols will also help states collect NDE data on their own, much as the LTPP data collection protocols helped states gather consistent and comparable pavement performance data. Consistently collected data allow for âapples to applesâ benchmarking among states. The accelerated bridge deck and superstructure experiment described to
8 the committee, as well as plans for developing deterioration models based on lab-collected and NBI and NBE performance data, appear to be promising avenues for developing future interim products. An ongoing dialogue with states about their needs for interim products would help build and sustain a stronger partnership for the future collection of bridge and pavement performance data. Recommendation 2A: The LTIP should be asking state DOTs, primarily through the LTPP and LTBP state coordinators, how the program can be most beneficial in producing interim products useful to state DOTs. In addition, the LTIP should document and share the development of such products to help sustain support for the program. Recommendation 2B: While recognizing uncertainty about future funding, general milestones for the data collection and development of management tools should be set and published in an online LTIP Annual Operational Plan to alert states to how the LTIP can assist states with MAP-21 requirements. Finding 3: The committee strongly endorses objectives of the LTIB Strategic Plan to âramp up collection of LTBP data,â âaccelerate the LTBP data collection effort,â and âexplore using alternative methods for improving the efficiency and reliability of data collection.â During the meeting, FHWA staff described changes to the RABIT-CEâ¢ data collection tool to use non-contact approaches to collecting NDE data, which is one example of accelerating the pace of the data collection. Also worth exploring are other ideas about RABIT-CEâ¢ and other NDE approaches for collecting sample data faster, possibly through interactions with Transportation Research Board (TRB) technical committees, through workshops with NDE experts and researchers, by soliciting ideas through LTBP paper competitions, and through other low-cost approaches. In light of the lengthy time period required for RABIT-CEâ¢ development, testing, and verification, FHWA may need to explore the options of leasing equipment and purchasing data collection services rather than developing and owning data collection assets. Recommendation 3: Given program resource constraints and the need to gather data from a large sample of bridges, the LTBP program should begin exploring ways of gathering data faster and more reliably. In so doing, the LTIP managers should reevaluate whether their current model of developing and owning data collection assets is suited to achieving these outcomes and consider the options of leasing equipment or purchasing services from private vendors supplying the equipment. Finding 4: As the LTBP programâs contractor begins collecting NDE data on bare decks, it would be timely for the LTBP managers to begin evaluating how data will be collected across all six of the LTBP programâs priority areas for measuring bridge performance. The committee understands that the LTIP does not have the resources to begin collecting such data today. Even so, it has taken several years of product testing and development to reach the point where NDE data on untreated bridge decks can be collected in earnest on a large scale. The LTIP program managers should begin exploring low-cost options for evaluating how to measure the performance of other important bridge components so that a data collection strategy is available if and when resources for additional data collection become available. Program managers are clearly aware of some of the data collection issues (e.g., that NDE techniques may work with polymer-coated decks but do not work for bridge decks with an asphalt overlay). Exploratory work through FHWAâs NDE lab includes
9 testing and developing approaches for measuring the performance of deck treatments, bearings, joints, coatings, and other bridge components. It may be possible for FHWA to also encourage universities with bridge and NDE expertise to develop and share ideas about measuring condition and performance, perhaps through interactions with TRB technical committees, workshops with experts, LTBP paper competitions, and other means that are not resource intensive. Recommendation 4A: To further thinking about how data for all six bridge elements will be collected, the LTBP managers should start making distinctions about which bridge components require a long-term performance data collection approach and which can rely, at least in the near term, on other data sources, such as accelerated laboratory testing that varies loads, environmental stresses, and other contributors to bridge deterioration. More information about data collection for all six bridge elements should be included in the Strategic Plan. Recommendation 4B: To support improvements in deterioration models in the near term for states and local governments to use in asset management, the LTIP should continue to collaborate with FHWAâs NDE laboratory and collaborate with other relevant programs within FHWA. The effort should start with deterioration models based on NDE and lab experiments. Such models can then be further calibrated and refined as field data become more available in the future. Finding 5: State DOTs may be able to provide data on bridge maintenance and expenditure histories, as well as other legacy records, that can supplement data in the LTBP program. Many states already provided legacy information for some of the bridges in the LTBP sample, such as plans, drawings, and maintenance records. Other states may have subsequently developed the ability to generate such data from their information systems since last requested. Some states might be able to generate such information in the future as their information systems become more sophisticated, particularly if they were aware of the LTIP programâs need for such information. Recommendation 5: The LTIP program managers should renew the dialogue with state DOTs, primarily through meetings with the LTBP state coordinators, regarding providing data on state maintenance actions and spending on bridges in the LTBP sample. More details on short- term objectives should be developed and shared as part of the Strategic Plan or an Annual Performance Plan. Finding 6: The LTIP needs to tell its story better to build support for the programs among states and other key stakeholders. Over the course of almost three decades, the LTPP program, in partnership with state DOTs, quietly assembled a database that has become vital to understanding and predicting pavement performance. The LTPP data are used by state DOTs and researchers for a wide variety of purposes and have become integrated into the curricula for educating future engineers. The LTBP program is embarking on a similar journey whose success is critical as asset management becomes central to state DOT planning and resource allocation. After spending years in planning, developing a sample, collecting legacy data, and developing a product for collecting NDE data on bridge decks, the LTBP program is now poised to begin collecting deck deterioration data on a large scale.
10 Recommendation 6: The LTIP program managers should develop a concerted program of outreach to key stakeholders that would include brief documents and brochures explaining the rationale and goals of the program, a high-level LTBP strategic plan targeted to decision makers, and a list of short-term objectives with deliverables. These documents should stress why the LTBP and LTPP programs are so important to meeting the needs of asset managers and owners today in addition to explaining the data the programs intend to collect over time. In closing, I would like to again thank the many FHWA staff who participated in our meeting and for their substantial and positive response to our previous recommendations. We look forward to a concerted effort to accelerate and expand bridge deck data collection and the provision of more details on short- and long-term objectives in response to the findings and advice in this report. The committeeâs recommendations are offered in the spirit of further improving the LTIPâs ability to assist agencies charged with asset management. The committee members support the LTIPâs goals and objectives and stand ready to assist in additional ways, as requested. Sincerely, Thomas Sorel Committee Chair Attachments A. Meeting Attendees B. Meeting Agenda