Influence of Soil-Structure Interaction on Seismic Design of Reinforced Concrete Integral Bridges

Abstract

Soil-structure interaction results in a significant modification of structural behavior, which in turn affects its seismic response. Most of the current structural analysis methods, prescribed by the design guidelines of different countries, do not account for it. The necessity of incorporating soil-structure interaction in the investigation of a wide range of bridge structures has been pointed out by several post-earthquake investigations and experimental and analytical studies.The current study is focused on the effect of soil-structure interaction on the seismic behavior of reinforced concrete (RC) piers of an integral bridge. First, a symmetric long-span RC bridge with fixed base is modeled using the computer program OpenSees. Next, the soil domain, along with the absorbing boundary conditions, is modeled in GID preprocessor program, and the bridge and soil domains are combined. Two types of scaled ground motions of different characteristics, namely, broadband and narrowband, are applied at the base of bridge, and the response of structure is studied by linear time history analysis. The forces at critical sections and displacement response are obtained.The same bridge with fixed base is modeled in the program SAP2000, and response spectrum analysis is carried out to find the design response of structure. The design response obtained from SAP2000 model is compared with results obtained from the model using OpenSees. It is observed that the design code overestimates the possible response significantly.

Soil-structure interaction: A state-of-the-art review of modeling techniques and studies on seismic response of building structures

“…Several studies on the use of different boundary conditions in dynamic SSI problems have been carried out. Among the various boundaries, (Jingbo and Yandong, 1998;Gentela, 2011) showed that viscous boundary is the most convenient one to be used in the timedomain analysis because it provides a good balance between efficiency and effectiveness.…”