Seismic Response of the Continuous Rigid-Framed Bridge with Super-High Piers Based on Shaking Table Tests

Abstract

Continuous rigid-framed bridges with super-high piers (CRFB-HP) have been widely applied in mountain areas. However, their seismic performance is still urgently to be clarified. In this study, the refined finite element model (FEM) of a CRFB-HP was constructed and verified according to the shaking table test results of its scaled model. On this basis, systematic elastic-plastic time history analysis of the CRFB-HP was conducted to investigate the influence of parameters on their seismic performance, including main bridge span, pier height and number of tie beams. The results show that CRFB-HP have the characteristic of long vibration periods and are more sensitive to long-period ground motions. Along the longitudinal and transverse directions, the peak pier top displacement and pier bottom bending moment of CRFB-HP are both relatively large under NLPL (+20~+70%) and NFPT (TP ≈ T1, +50~+120%) excitations. For the same span, the peak pier top displacement increases with the pier height increasing, while the peak pier bottom bending moment decreases with the pier height increasingFor the same pier height, the peak pier top displacement and peak pier bottom bending moment both increase with the span length increasing. Moreover, the pier height change has a greater effect on the pier top displacement than that of the span change. CRFB-HP show obvious high-order response participation (HRP) under different ground motions. The NFPT (TP ≈ T1), ground motions can significantly increase HRP. Moreover, compared with cast-in-place CRFB-HP, the HRP of a fabricated super-high pier is greater (+20~+30%). The peak pier top displacement and pier bottom bending moment both decrease with the increase in the number of tie beams. The reasonable arrangement of tie beams can improve the lateral seismic performance of CRFB-HP. However, compared to the cast-in-place CRFB-HP, the peak pier top displacement is larger, and the peak pier bottom bending moment is smaller, for the fabricated CRFB-HP.