TRB's National Cooperative Highway Research Program (NCHRP) Report 654: Evaluation and Repair Procedures for Precast/Prestressed Concrete Girders with Longitudinal Cracking in the Web explores the acceptance, repair, or rejection of precast/prestressed concrete girders with longitudinal web cracking. The report also examines suggested revisions to the American Association of State Highway and Transportation Officials' Load Resistance Factor Design Bridge Design Specifications and measures to develop improved crack control reinforcement details for use in new girders.
Appendices A th
TRB's National Cooperative Highway Research Program (NCHRP) Report 647: Recommended Design Specifications for Live Load Distribution to Buried Structures explores recommendations to revise the American Association of State Highway and Transportation Officials Load and Resistance Factor Design Bridge Design Specifications relating to the distribution of live load to buried structures.
The report examines development of simplified design equations (SDEs) for structural response based on three-dimensional (3D) analysis of 830 buried culverts. In addition, the report suggests guidelines
TRB's National Cooperative Highway Research Program (NCHRP) Report 656: Criteria for Restoration of Longitudinal Barriers explores the identification of levels of damage and deterioration to longitudinal barriers that require repairs to restore operational performance.
Ductile iron pipe (DIP) was introduced about 50 years ago as a more economical and better-performing product for water transmission and distribution. As with iron or steel pipes, DIP is subject to corrosion, the rate of which depends on the environment in which the pipe is placed. Corrosion mitigation protocols are employed to slow the corrosion process to an acceptable rate for the application. When to use corrosion mitigation systems, and which system, depends on the corrosivity of the soils in which the pipeline is buried.
The Bureau of Reclamation's specification for DIP i
TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 398: Cathodic Protection for Life Extension of Existing Reinforced Concrete Bridge Elements examines the use of cathodic protection by state transportation agencies for controlling corrosion on existing reinforced concrete bridge elements. The report also explores the different types of cathodic protection systems, highlights case studies of states using these systems, and reviews reasons why public agencies may or may not employ cathodic protection.
TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 397: Bridge Manangement Systems for Transportation Agency Decision Making explores how bridge management systems are employed by transportation agencies in making network-level decisions on resource allocations for their bridge programs.
TRB's National Cooperative Highway Research Program (NCHRP) Report 638: Guidelines for Guardrail Implementation explores guidance on selecting the appropriate barrier performance level for the installation of longitudinal barriers.
The following appendices to NCHRP Report 638 are only available online.
- Appendix A, Guardrail Use Guidelines for Benefit/Cost = 2
TRB's National Cooperative Highway Research Program (NCHRP) Report 632: An Asset-Management Framework for the Interstate Highway System explores a framework for applying asset-management principles and practices to managing Interstate Highway System investments.
TRB's National Cooperative Highway Research Program (NCHRP) Report 620: Development of Design Specifications and Commentary for Horizontally Curved Concrete Box-Girder Bridges explores proposed specifications and examples for the design of horizontally curved concrete box-girder highway bridges.
Potential LRFD specifications and design examples illustrating the application of the design methods and specifications are available online as appendixes to NCHRP Report 620.
Appendix A - [more]
TRB's National Cooperative Highway Research Program (NCHRP) Report 628: Self-Consolidating Concrete for Precast, Prestressed Concrete Bridge Elements explores recommended guidelines for the use of self-consolidating concrete (SCC) in precast, prestressed concrete bridge elements. The report examines the selection of constituent materials, proportioning of concrete mixtures, testing methods, fresh and hardened concrete properties, production and quality control issues, and other aspects of SCC.