双柱式桥墩刚度对桥梁地震响应分析

为研究桥墩刚度对高墩桥梁抗震性能的影响，以带溪高架桥为研究背景，利用midas-civil选波工具选取合适地震波，建立了一致激励地震作用下的连续梁桥，并考虑P-Δ效应和非线性的影响，分析桥墩高度、桥墩截面尺寸及形式对桥梁抗震影响。通过改变墩径（墩径由1.2 m变化至2.4 m）抗震分析表明双柱墩直径对墩顶位移影响效果并不明显，墩径过大会导致桥墩内力较大；对不同墩高（墩高由20 m变化至50 m）地震响应分析表明墩高对墩顶位移起到控制作用，但墩高变化对桥墩所受轴力影响不大；由于P-Δ效应和约束影响，全桥为中间高墩、两边矮墩时具有较小的地震响应；在墩高为30 m情况下，相对于薄壁墩和实体墩，双柱式墩具有较好的抗震性能。

Effects of Double-column Pier Stiffness on Seismic Response of Bridge

In order to investigate effects of the pier stiffness on the seismic performance of the bridge, this paper, adopting the Daixi Viaduct as the research object and the midas-civil wave tool for selecting the appropriate seis-mic wave, establishes a continuous girder bridge under the action of uniform excitation. By taking the P- Δand nonlinear effects into account, it analyzes the influence factors such as different pier heights, section sizes and forms. The seismic analysis results show that the diameter of double column pier has a little effect on the pier top＆#39;s displacement by changing the diameter from 1.2 meters to 2.4 meters, and the diameter oversize leads to the in-crease of pier force;The height of pier has control over the pier top displacement, but the pier height has a little ef-fect on the axial force of pier by changing the height from 20 meters to 50 meters;Because of P-Δeffect and the influence of boundary constraints, the bridge whose middle pier is high and side piers are short has smaller seis-mic response;In case the pier height is 30 meters, the double column pier has better seismic performance, com-pared to the thin-walled pier and solid pier.