ABSTRACT
The paper focuses on the dynamic and seismic behavior of integral abutment steel bridges considering nonlinear soil-structure interaction, and the effects of design parameters of the integral abutment system on bridge behavior. 3-D finite element model of an integral abutment steel bridge was established with the SAP2000 software, and nonlinear link elements and damper elements were used to model the soil reactions behind the abutment and around the piles. Modal analysis and nonlinear time-history analysis were conducted, with corresponding parametric studies. Results indicate that: Compacting the backfill, increasing the abutment height-to-thickness ratio, and increasing the foundation stiffness will increase the dominant longitudinal frequency of the bridge structure, while H pile orientation has little influence. When satisfying the design requirements and in a reasonable range, compacting the backfill behind the abutment, increasing the abutment height-to-thickness ratio, increasing the foundation stiffness, and orienting the steel H pile to bend about its strong axis can effectively reduce the pile-top displacement, as well as seismic response of girders, abutments and piers, but increasing the foundation stiffness will obviously increase pile-top moment at the same time.
