The new Mechanistic Empirical Pavement Design Guide (MEPDG) and other existing pavement design guides use resilient modulus as the primary input parameter when characterizing stiffness of subsoils and unbound bases. Resilient modulus of soils is typically determined either by using laboratory tests or field tests. This report was prepared to describe the significance of the resilient modulus property, various methods of determining this property of subsoils and unbound bases, and the application of this parameter in the MEPDG. The report will be of interest to design, geotechnical and materials engineers and technicians. Information collected in this synthesis was based on a comprehensive literature review, surveys of pavement design, materials and geotechnical engineers from state departments of transportation (DOTs), and selected interviews. Information collected also included research reports from studies conducted by several state DOTs.
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Author: Hyman, William A | Size: 1.98 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2009 | pages: 112 | ISBN: 9780309098250
Performance-Based Maintenance Contracting (PBMC) provides incentives and disincentives to achieve desired outcomes or results from the maintenance contractor. This is distinct from the more usual practice for highway maintenance contracting—low bid combined with method specification. This report explores experience with PBMC in places where it has been adopted, including such issues as whether it has the potential to reduce costs and improve maintenance levels of service. Methods for implementing PBMC are also discussed. The report is likely to be useful for those agencies who are evaluating whether to include PBMC in their highway maintenance program. Information for this study was gathered by literature review of international experience, domestic U.S. state experience, federal government experience, and warranty contracts, as well as surveys conducted of state transportation agencies, Canadian provincial agencies, and a sampling of private firms. The surveys were augmented with individual interviews.
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Performance-Based Construction Contractor Prequalification
Author: Gransberg, Douglas D University of Oklahoma, Norman Riemer, Caleb University of Oklahoma, Norman | Size: 2.21 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2009 | pages: 109 | ISBN: 9780309098281
Performance-based construction contractor prequalification seeks to add contractors' past performance to the prequalification process. Performance criteria may include construction quality, keeping to schedule, and safety record. This report summarizes experience and practice of state transportation agencies and includes information from non-transportation construction. The focus is on design-bid-build projects; however, there is also information on design-build and construction manager/general contractor projects. Information was gathered through a literature review augmented by content analyses of administrative prequalification documents and Requests for Qualifications. A survey was administered to state transportation agencies and Canadian provincial transportation agencies. Finally, structured interviews were conducted with construction contractors to obtain an industry perspective.
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Author: Russell, Henry G | Size: 15.77 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2009 | pages: 83 | ISBN: 9780309098304
Bridges built with adjacent precast, prestressed concrete box beams are a popular and economical solution in many states because they can be constructed rapidly and most deck forming is eliminated. Bridges constructed with box beams have been in service for many years and have generally performed well. A recurring problem, however, is cracking in the longitudinal grouted joints between adjacent beams, resulting in reflective cracks forming in the wearing surface. This in turn may lead to leakage, corrosion, and, in severe cases, complete cracking of joints and loss of load transfer. This study discusses current design and construction practices that are reported to reduce the likelihood of longitudinal cracking in box beam bridges. Information for the study was gathered through a literature review. In addition, state and Canadian provincial transportation agencies were surveyed, and the survey was augmented with selected individual interviews.
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Scour is the primary cause of bridge failure in the United States. There are more than 20,000 highway bridges that are rated "scour critical." Selected bridges have been monitored for more than ten years and valuable field data have been obtained from these bridges. This report presents the current state of practice for fixed scour bridge monitoring. It will be useful for bridge owners, in particular those responsible for bridge maintenance and safety. Information for this report was obtained through literature review, survey of the state transportation agencies, and selected interviews.
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This study gathers information on current practices that senior managers at transportation agencies use to make network-level decisions on resource allocations for their bridge programs. In particular, the study explores how agency bridge management systems are employed in this process. Information was gathered through a review of literature on U.S. and international bridge management, a survey of U.S. and Canadian transportation agencies, and 15 in-depth interviews with state department of transportation executive and bridge managers.
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Cathodic Protection for Life Extension of Existing Reinforced Concrete Bridge Elements
Author: Sohanghpurwala, Ali Akbar | Size: 2.08 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2009 | pages: 56 | ISBN: 9780309098397
Cathodic protection is the only technology that can directly stop corrosion in reinforced concrete structures. This report examines the use of cathodic protection by state transportation agencies for controlling corrosion on existing reinforced concrete bridge elements. There are descriptions of different types of systems and case studies of states using these systems. As well, there is analysis of reasons that public agencies may or may not employ cathodic protection. Information was gathered through a literature review and a survey of U.S. state transportation agencies and Canadian provincial transportation agencies, augmented by selected interviews.
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During all phases of the transportation planning, development, and operations process environmental data are needed to prepare environmental documents, obtain permits, design and construct road improvements, mitigate or avoid impacts, monitor mitigation, and conduct maintenance activities. The objectives of this synthesis were to survey transportation and natural resource professionals familiar with transportation systems to identify ecological survey needs related to transportation activities and to identify technologies, techniques, and innovative methods to fulfill those needs. These technologies, techniques, and methods, collectively called new approaches, include data collection, its analysis and delivery, how it can be used in planning and operations, and cooperative working relations. The audience for this synthesis includes transportation professionals responsible for planning, designing, constructing, operating, and maintaining transportation projects and the road corridor in an environmentally and fiscally responsible manner, as well as professionals in natural resource agencies and other organizations who work with departments of transportation (DOTs) on these issues. The synthesis is based on an electronic survey conducted in early 2008 that was sent to all state DOTs and state fish and wildlife agencies, and concurrent literature and new initiatives searches.
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Transportation agencies are developing procedures and guidelines for managing the quality of pavement data collected to ensure the data meet the needs of the pavement management process. This study reviews the quality management practices being employed by public highway agencies for automated, semi-automated, and manual pavement data collection and delivery. Information was gathered through literature review, surveys of U.S. state and Canadian province public agencies and private contractors, and selected interviews.
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Author: Gransberg, Douglas D | Size: 5.55 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2010 | pages: 123 | ISBN: 9780309143196
This study gathers information on the use of highway microsurfacing treatments by transportation agencies in the United States and Canada. Microsurfacing is a polymer-modified asphalt emulsion cold-mix surface treatment that can remedy a broad range of problems on today's highways. The report identifies and discusses practices reported as effective by transportation agencies in microsurfacing project selection, design, contracting, equipment, construction, and performance measures. Information used in this study was acquired through a review of the literature, a survey distributed to maintenance engineers at all U.S. state departments of transportation (DOTs) and Canadian provincial transportation agencies, evaluation of all 50 state DOT microsurfacing specifications as well as the one used by the U.S. Federal Lands Highway Division, and case studies of six microsurfacing projects from five U.S. states and one Canadian province.
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