An Analytical Study on Seismic Response of Steel Bridge Piers Considering Soil-Structure Interaction

Publisher Summary Three analytical models—soil-fixation model, soil-spring model, and soil-meshing model—are prepared to grasp seismic behavior considering the effect of base and ground, and to compare the behavior of piers considering soil-structure interaction. The steel bridge pier is modeled by a single-degree-of-freedom system with a concentrated mass at the top of the pier. In the soil-meshing model, the size of the foundation area considered is 60 m horizontally and 20 m vertically. Earthquake motions, used for the Ground Type II, are Level 2 Type II earthquake motions. These earthquake motions are assumed to be input in the ground surface level. Then, earthquake motion at a certain depth must be estimated in the soil-meshing model. For this purpose, necessary earthquake motion is estimated by using a program, SHAKE. The equivalent elastic shear modulus and damping coefficient obtained from the analysis using the SHAKE are used in the soil-meshing model. In order to observe the response difference affected by natural period of bridge pier, a parametric study on slenderness ratio parameter is carried out. For piers with the same natural period, maximum and residual response displacement of the soil-spring model, are almost the same to those of the soil-fixation model.