BACKGROUND

A segmental bridge is constructed in short sections or segments that are either precast or cast-in-place concrete. Segmental bridges were first built in the United States in the 1970s and have proven to be an efficient design for long span bridges. The earliest segmental bridges were designed, constructed, and load rated using methods that were not codified by the American Association of State Highway and Transportation Officials (AASHTO), and differ significantly from the current AASHTO load and resistance factor design (LRFD), load factor rating (LFR), and load and resistance factor rating (LRFR) methodologies. As a result, the use of current AASHTO LFR and LRFR methodologies to load rate existing segmental bridges has resulted in a significant capacity reduction in comparison to the old load rating procedures. In addition, there are limited resources for owners and consultants to accurately load rate segmental bridges due to the complexities. There is a need to develop load rating guideline to accurately determine the load rating capacity of segmental bridges to ensure safety and mobility.

OBJECTIVES

The objectives of this research were to (1) develop a proposed AASHTO guideline for load rating of segmental bridges; (2) propose revisions for the AASHTO Manual for Bridge Evaluation (including LFR and LRFR) and any necessary related revisions to the AASHTO LRFD Bridge Design Specifications; and (3) develop detailed rating examples with supporting training materials to demonstrate the proposed guideline and revisions to AASHTO specifications.

STATUS: Will be published as NCHRP Reseach Report 1128