地铁上盖大底盘多塔层间隔震结构的抗倒塌性能分析

Collapse Performance Analysis of Story Isolated Muliti-tower Structures with Large Base on Subway

为了深入研究在强震作用下层间隔震结构的抗倒塌能力,使用ETABS有限元分析软件对大底盘多塔层间隔震结构进行增量动力时程分析,基于增量动力时程分析结果,按照FEMA P695和《建筑结构抗倒塌设计规范》的评价标准,结合倒塌储备系数,定量地评价了地铁上盖大底盘多塔层间隔震结构的抗倒塌能力。研究结果表明:在强震作用下,大底盘多塔层间隔震结构中的上部结构、下部结构及隔震支座均满足两种规范对结构抗倒塌能力的要求;相比于上部结构和大底盘,大底盘多塔层间隔震结构的隔震支座倒塌概率最大;根据上述分析结果,得出隔震支座是大底盘多塔层间隔震结构的薄弱点,然后提出使用高阻尼橡胶支座来减小大底盘多塔层间隔震结构的倒塌概率,并对使用高阻尼橡胶支座结构与原叠层橡胶支座结构进行隔震性能的对比分析;相较于铅芯橡胶支座,高阻尼橡胶支座在减小隔震层位移、上部结构的位移角、楼层加速度和楼层扭矩具有明显的优势。

In order to understand the damage status of multi-tower structure under earthquake action and ensure the collapse resistance of isolation structure under strong earthquake action,ETABS was used to conduct incremental dynamic analysis(IDA)of large chassis multi-tower structures.Based on the results of IDA,according to the evaluation standard of FEMA P695 and Code for Collapse Resistance design of Building Structures,combined with the collapse margin ratio,the collapse capacity of large chassis and multi-tower storey spacer structures on the subway roof was quantitatively evaluated.The results show that the superstructure,substructure and isolation bearings of the multi-tower spacer structure of large chassis could meet the requirements of the two codes for the collapse capacity of structures under the action of large earthquakes.Compared with the superstructure and the large chassis,the collapse probability of isolation bearings of the large chassis with multiple tower floors is the largest.According to the above analysis results,it is concluded that the isolation bearing is the weak point of the multi-tower structure with large chassis.Then,it is proposed to use high damping rubber bearings to reduce the collapse probability of multi-tower structure with large chassis,and the isolation performance of high damping rubber bearings is compared with that of the original laminated rubber bearings.The results show that compared with the lead rubber bearing,the high damping rubber bearing has obvious advantages in reducing the displacement of isolation layer,displacement angle of superstructure,floor acceleration and floor torque.