Analysis of Elastic-Plastic Seismic Response of a Low-Pylon Cable-Stayed Bridge under a Rare Earthquake

In order to research the features of an elastic-plastic response of a low-pylon, cable-stayed bridge under a rare earthquake, a Midas model for an elastic-plastic analysis was set up based on the theory of nonlinear time-history analysis and the definition ofabeam-column element model with Clough hysteretic behavior. In this model, a low-pylon, cable-stayed bridge with span arrangement 144 + 288 + 144 m was taken as an engineering background. Three sets of seismic waves accorded with site characteristics of the bridge site were selected, and the elastic-plastic seismic responses of the bridge under rare earthquake were solved. The results showed that:(1) only longitudinal displacement of double thin-wall piers yield and (2) the piers generate unrecoverable residual deformation when entering into an elastic-plastic state. Due to the elastic-plastic seismic response and the ductility seismic norm of the bridge being related to the spectral characteristic of seismic wave, checking the effects caused by only one set of seismic waves will not guarantee security of the ductility seismic design of bridge.