桥梁高墩地震反应中高阶振型贡献程度的分析

Analysis of Higher Modes Contribution to Seismic Response of High Bridge Pier

针对山区典型不同高度桥墩,通过增量动力分析(Incremental Dynamic Analysis-IDA)研究高墩在地震作用下从弹性状态到极限状态的整个反应过程,得到不同塑性程度下墩身的位移分布,并通过对各级地震动输入下墩底曲率达到最大时刻的结构刚度进行瞬时模态分析,探讨了整个非线性过程中瞬时振型、瞬时振型参与系数、瞬时质量参与系数以及各阶瞬时周期对应的延性位移谱值随着墩底曲率增加的变化,揭示了整个非线性过程中高阶振型参与程度的变化,进而对在各级地震动作用下墩底达到曲率最大值时刻的墩身位移分布中的高阶振型贡献程度进行评估。

For the bridges pier with different height in mountainous areas, the incremental dynamic analysis （IDA） is used to research the entire process of nonlinear seismic response from elastic state to ultimate state, thus getting the displacement cures of pier under different degrees of nonlinearity. Modal analysis is carried out for transient structure stiffness when pier curvature reaches the maximum value under different lever ground motion. The change trend of transient mode shape, transient modal participation factors, transient modal participating mass ratios and displacement spectral amplification of constant-ductility inelastic spectra are investigate with the increasing of pier base curvature, revealing the trend of higher modes contribution, and then an evaluation is made of higher modes contribution to the displacement curves when the pier base curvature reaches the maximum value under different lever ground motion.