大跨斜撑无柱地铁车站结构地震响应分析

为研究大跨斜撑无柱地铁车站地震响应特性,基于三维静-动力耦合非线性有限元模型,分析在不同地震动作用方向下的地震响应规律,揭示结构地震损伤演化过程。分析表明:设防地震和罕遇地震作用下车站结构的最大层间位移角分别为1/1 352和1/602,满足规范要求;地震作用对斜撑轴力、侧墙端部剪力和底板跨中弯矩的放大作用显著;随输入地震动强度的增加车站顶板加速度放大系数依次减小,竖向地震动对相对竖向位移的影响不可忽视;斜撑两端、墙板交界处和开窗周围区域是结构的抗震薄弱部位;强震作用下,车站结构塑形损伤积累且地震动空间效应显著,宜按空间问题进行抗震分析。研究成果可为类似结构的抗震设计与分析提供参考。

Seismic Response Analysis of Long-Span Diagonal Braced Non-Column Subway Station Structure

In order to study the seismic response characteristics of long-span diagonal braced non-column subway station, based on a 3D static-dynamic coupling nonlinear finite element model, the seismic response law under different seismic action directions is analyzed, and the evolution process of structural seismic damage is revealed. The analysis shows that the maximum inter-story displacement angles of the station structure of fortification earthquakes and rare earthquakes are 1/1 352 and 1/602, which meet the requirements of the code. The seismic action has a significant amplification effect on the axial force of the diagonal brace, the shear force at the end of the side wall and the mid-span bending moment of the bottom plate. With the increase of input ground motion intensity, the acceleration amplification coefficient of station roof decreases successively, and the influence of vertical ground motion on the relative vertical displacement is not be ignored. Diagonal braces, the junction of wall panels and the area around the window openings are the seismic weak points of the station structure. Under the action of strong earthquakes, the plastic damage of station structure accumulates and the spatial effect of ground motion is significant, so the seismic analysis should be carried out according to the spatial problem. The research results can provide reference for seismic design and analysis of similar structures.