Improved Load Rating of an Open-Spandrel Reinforced-Concrete Arch Bridge

Abstract

An open-spandrel reinforced-concrete arch bridge in west central Indiana was load posted on the basis of a simplified analytical evaluation. The posting was controlled by the shear-strength limit state of the transverse floor beams. Although transverse reinforcement was provided according to the original construction plans, there were regions that lacked shear reinforcement, which deemed these members critical. This paper presents the results of an analytical and experimental evaluation performed on one of the critical members of the bridge. The analytical models considered a spatial structural analysis of the bridge deck and a three-dimensional finite-element analysis of the entire bridge structure. Five static truck tests were also conducted to compare the measured response with those obtained analytically. The load rating of the bridge was conducted by using the live-load test results and finite-element analysis. Using simplified structural analysis does not always provide accurate load-rating results for all limit states. Moreover, the use of load testing and refined analysis demonstrated that the bridge exhibited a higher load-carrying capacity than the original posting load.