基于分体柱的地铁车站结构抗震性能研究

Research on Seismic Performance of the Underground Subway Station with Split Columns

浅埋地下车站结构中柱和地面高层结构底层中柱相似,地震作用下均需承担较大的竖向压力,易因变形能力不足发生脆性破坏。在某2层3跨地铁车站结构中引入地面高层结构中的分体柱设计理念,形成新型地下车站结构抗震体系。首先,通过拟静力推覆分析对比了传统钢筋混凝土中柱和分体柱在轴向压力作用下的水平变形特性;然后,建立了土-结构相互作用的拟静力推覆分析有限元模型,从关键截面内力、关键构件变形能力、关键构件塑性损伤等角度对比了传统钢筋混凝土中柱和分体柱的地下结构抗震性能差异。研究结果表明,将分体柱应用于2层3跨地铁车站结构中可提高整体结构抗震性能,其工作机理是避免分体柱承担过大的剪力和弯矩,并充分发挥分体柱竖向支撑能力和水平变形能力。

The center columns of shallow buried underground subway station structures are similar to columns in 1st floor of high-rise structures in that both are subject to large vertical pressures under earthquake action and are prone to brittle failure with insufficient deformation capacity.In this paper,the design concept of split column,which is used in high-rise structures,is introduced into a two-layer and three-span subway station structure to form a new underground structural seismic system.Firstly,the horizontal deformation characteristics of ordinary reinforced concrete column and split column under high axial pressure are compared by the quasi-static pushover analysis.Secondly,a numerical model is established for the quasi-static pushover analysis of the soil-structure system to compare the differences in seismic performance between the prototype structure and the new structure from the perspectives of internal forces of critical sections,deformation capacity of critical members,and plastic damage of critical members.The analysis results show that the split columns applied in two-layer and three-span subway stations can improve the seismic performance of the structure,and the working mechanism is to avoid the split columns from taking excessive shear forces and bending moments while giving full play to the vertical support capacity and horizontal deformation capacity of the split columns.