Parametric study on the thermal response of curved integral abutment bridges

Abstract

Integral abutment bridges (IABs) are a common structural system for short to moderate span bridges. Construction of curved IABs, however, is limited partly due to lack of quantified performance. Many departments of transportation (DOTs) in the USA therefore restrict or even prohibit the design of curved IABs with curved steel girders. However, the application of design concepts of in-plan curved superstructure geometry and integral abutments can offer various advantages. Often the design of IABs considers the response of structural components separately without considering the connectivity between them and simplifies design to a two dimensional analysis. Therefore, this analysis method fails to capture the system response of curved IAB bridges which requires an accurate estimate of the temperature induced displacement/stresses and the effects of the curvilinear alignment. In this paper, a research program using finite element (FE) modeling to simulate the abutment–pile and abutment–superstructure connections in curved IABs is reported. A detailed, three dimensional, FE model of a curved IAB located in Stockbridge, Vermont, USA was used as a prototype to evaluate the behavior of curved IABs under thermal loading. A parametric study was carried out to investigate the effects of bridge curvature and abutment backfill soil type. Moreover, additional FE models were created to investigate the effect of degree of lateral restraint provided by the U-shaped wingwalls integral with abutments and the interior pier. The results, including abutment displacements, moments at abutment piles, earth pressures on abutments and wingwall, and bridge superstructure forces, are reported and compared with the responses of conventional curved bridges containing expansion joints.