Effect of Superstructure Temperature Changes on Intermediate Pier Foundation Stresses in Integral Abutment Bridges

Abstract

Structural members that are restrained against motion can develop internal stresses when subjected to changes in temperature. The phenomenon of temperature-induced internal stresses in superstructure members of bridges has prompted the development of codified provisions for determining superstructure temperature load effects. The objective of this study, as a means of assessing the robustness of existing design provisions for a selected bridge case, was to quantify the effect that thermal stresses have on underlying foundation systems, such as intermediate bridge piers in integral abutment bridges. The objective was met by, in part, instrumenting a multispan integral abutment bridge with temperature and bridge response remote-monitoring devices. Data obtained from the remote-monitoring program are made available in graphical form to interested parties via real-time updates on a dedicated website. Simultaneous to the field-monitoring program, a detailed analytical study of the integral abutment bridge was undertaken. Through pairing of in-service field measurements with finite-element analysis of temperature loadings on the selected bridge, the contributions to foundation stresses associated with changes in temperature in the superstructure were quantified. Findings from this study support that available design provisions are capable of leading to conservative bridge foundation designs.