节段装配式悬臂混凝土箱形梁桥动力响应分析

Dynamic Response Analysis of Segmental Assembly Cantilever Concrete Box Girder Bridge

为研究节段装配式悬臂混凝土箱形梁桥地震动响应,以郑州市四环线快速化工程为背景,采用有限元法对结构进行模态分析,研究结构自振周期与频率;选取现有地震波与拟合人工波分别进行竖向、水平作用下的地震动响应分析,研究竖向地震作用下节段装配式箱形梁边跨与中跨跨中变形与加速度,以及水平地震作用下桥梁边墩与中墩墩顶变形和加速度响应。结果表明:节段装配式悬臂混凝土箱形梁桥振型主要表现为扭转弯曲、竖向弯曲;竖向地震作用下,中跨跨中顶板截面竖向位移稍大,EL-Centro波作用下中跨竖向加速度稍大,人工波作用下边跨与中跨竖向加速度差异不大;水平地震作用下,1~#墩和2~#墩墩顶部节点水平位移、水平加速度差异亦不大。

In order to study the seismic response of segmental fabricated cantilever concrete box girder bridge, based on the rapid engineering of Zhengzhou Fourth Ring Line, the natural vibration period and frequency of the structure are studied by modal analysis using finite element method. The existing seismic wave and the fitted artificial wave are selected to carry out the seismic response analysis under the vertical and horizontal action respectively. The deformation and acceleration of the side span and middle span of the segmental fabricated box girder under the vertical earthquake, and the deformation and acceleration response of the bridge side pier and middle pier top under the horizontal earthquake are analyzed. Research shows that the vibration modes of segmental fabricated cantilever concrete box girder bridge are mainly torsional and vertical bend. Under the action of vertical earthquake, the vertical displacement of the middle span top section is slightly larger, the vertical acceleration of the middle span under the EL-Centro wave is slightly larger, and the vertical acceleration difference between the side span and the middle span under the artificial wave is small. Under horizontal earthquake, the horizontal displacement and horizontal acceleration of the top node of 1pier and 2pier have little difference.