以第一周期为8.57s的某超限高层框架-核心筒建筑结构为研究对象,选取7条实际长周期主余震序列型地震动,并与单主震地震动一起作为输入样本,通过有限元软件PERFORM-3D对结构进行非线性动力时程分析;着重从结构整体、楼层滞回耗能情况及构件材料损伤等反应量角度来研究主余震地震动对超限高层建筑结构抗震性能的影响。研究结果表明,相对单主震地震动,结构在主余震地震动作用下整体滞回耗能增幅最大达到31.34%,楼层滞回耗能增幅最大可达到45.71%;同时余震地震动作用会使结构中构件损伤逐步累积过渡,导致部分构件转变为严重损伤状态。因此,对于超限高层建筑结构,仅根据现行规范或超限高层建筑专项审查研究超限高层在单次主震地震动作用下的抗震能力并不能很好地评估结构的抗震性能,建议对超限高层建筑结构进行非线性动力时程分析时补充余震地震动作用的影响,从而全面、安全可靠地评估超限高层建筑结构的抗震性能。
An high-rise frame-corewall structure beyond the code-specification with the natural vibration period of 8. 57 s was selected as research object. PERFORM-3D FEM software was employed to conduct the nonlinear dynamic time-history analysis of the structure under input samples of sequence-type ground motions of seven actual long-period main aftershocks and single main shock ground motions. Structural hysteretic energy dissipation,floor hysteretic energy dissipation and material damages of structural components were mainly investigated to study the effects of main aftershock ground motions on seismic performances of high-rise building structure beyond the code-specification. Results show that the total structural hysteretic energy dissipation could be up to 31. 34% and floor hysteretic energy dissipation under main aftershock ground motions could be up to 45. 71% in maximum respectively more than that under only single main shock ground motions; and material damages of structural members are accumulated continually under aftershock ground motions,and serious damage state could be found in some structural components. Therefore, for high-rise building structures beyond the code-specification,seismic performance of the structure might not be estimated properly if only single main shock ground motions are adopted according to the current code or specification of peer review for high-rise buildings beyond the code-specification. Aftershock ground motions are recommended to be supplemented to the nonlinear dynamic time-history analysis of high-rise building structures beyond the code-specification,which can reasonably and safely evaluate seismic performances of high-rise building structures beyond the code-specification.