NCHRP Report 620 provides specifications, commentary, and examples for the design of horizontally curved concrete box-girder highway bridges. The report details the development of the design procedures. Recommended LRFD specifications and design examples illustrating the application of the design methods and specifications are included in an Appendix. The material in this report will be of immediate interest to bridge designers.
Many concrete box-girder highway bridges are constructed on horizontally curved alignments. In some instances, problems such as bearing uplift, cracked diaphragms and piers, and lateral tendon breakout have occurred. The AASHTO Bridge Specifications do not adequately address these and other issues either in the provisions or commentary.
AASHTO has recently incorporated provisions for the design of horizontally curved steel bridges into the LRFD Bridge Design Specifications. These specifications include specific guidance on when horizontal curvature effects must be considered. Bridge owners and designers need specifications and commentary, as well as examples that provide design guidance for horizontally curved concrete box-girder highway bridges.
The objective of NCHRP project 12-71 was to develop specifications, commentary, and examples for the design of horizontally curved concrete box-girder highway bridges. This objective has been accomplished. The research was performed by Nutt, Redfield & Valentine, Orangevale, California in association with David Evans & Associates, Inc., San Diego, California and Zocon Consulting Engineers, Inc., Folsom, California. The report and appendices fully document the effort to develop the design procedures.