A SIMPLIFIED METHOD FOR SEISMIC PERFORMANCE EVALUATION OF STEEL BRIDGE PIERS WITH THIN-WALLED STIFFENED BOX SECTIONS

摘要

This paper proposes a simplified seismic evaluation method for the thin-walled stiffened box steel pier to predict its strength and ductility. In this method, two modified bilinear material models for the fiber-beam element are suggested to include the local buckling of the base stiffened plate. An experiment validated a shell element based model, which was selected for comparison with the proposed fiber-beam based model. Twelve numerical cases were then simulated by the shell element based model and the fiber-beam element based model, respectively, and their accuracies were compared with each other. Numerical results showed that the proposed pushover method, employing the amended bilinear kinematic material model for the fiber beam element, is of good accuracy. If the maximum strength is taken as the ultimate point, the bilinear material model, replacing the yield point by the buckling stress, is recommended. If 95 percent of the maximum strength after the peak is regarded as the ultimate point, the elastic-perfectly plastic material model is suggested.