Shaking table tests and numerical simulations of a small radius curved bridge considering SSI effect

摘要

Focusing on a small radius curved bridge, a serious of shaking table tests and corresponding numerical finite element analyses were conducted for a 1/16 scaled curved bridge model considering SSI (Soil-Structure Interaction) effect. In the testing and simulating, the strong motion records with different frequency characteristics and durations, El Centro record from Ms6.7 Imperial Valley earthquake and Wolong record from Ms8.0 Wenchuan earthquake, were as the input motions. The dynamic property, vibration response, damage rule, and failure mode of the curved bridge were obtained preliminarily. The experimental results showed that the transverse stiffness of this soil-pile-bridge structure system was larger than the longitudinal stiffness; the obvious torsion effect of the model structure was observed in the tests under the input motion in uni-direction, and the larger was the input motion PGA, more obvious was the torsion effect; the seismic responses were more sensitive to input motions with relative low-frequency components; the damage degree of the pier bottom increased from short to high pier, and the rubber bearings at side piers appeared two different failure modes induced by the longitudinal slope. Compared with straight bridges, the curvature radius made curved bridges more prone to causing rotation and displacement. Furthermore, finite element analyses were conducted by using the plastic-damage model for concrete, and equivalent soil springs method for pile-soil interaction, respectively. The simulations were in agreement with the test results satisfactorily, moreover the differences between these results were discussed in detail and the errors were in an acceptable range. These studies would be used to provide insights for the further research and theoretical design of curves bridges.