长周期地震作用下考虑碰撞效应的偏心隔震结构损伤性能评价

Damage performance evaluation of eccentric isolated structure system considering impact under long-period ground motions

由于隔震层位移过大或隔震沟间距设置不当会造成偏心隔震建筑结构与周围挡土墙发生碰撞。合理评估扭转耦合效应及碰撞效应对偏心隔震结构损伤性能的影响具有十分重要的意义。建立了单层偏心隔震结构弹塑性侧扭耦合分析模型,并基于Park-Ang损伤指标定义了上部结构的损伤。以近断层地震和远源长周期地震动作为输入,采用弹塑性时程分析方法对单层单向偏心隔震系统进行损伤性能评价。对相关重要参数进行了地震影响分析。研究结果表明,与设计地震动相比,在长周期地震作用下考虑碰撞效应的结构损伤值较高,如果间距设置不当甚至会造成结构损伤失效。上部结构及隔震层偏心会对结构损伤产生不利响应。合理设计隔震沟间距可以保证隔震结构在罕遇地震下不出现失效现象。

Too large isolation layer displacements or inadequate isolation ditch distances will lead to seismic impact between eccentric isolated structure and the surrounding retaining wall.It is very significant to reasonably assess the effect of lateral-torsion coupling and impact on damage performance of the isolated structure.For this problem,the lateral-torsion coupling analysis model for single-direction eccentric isolated structure is established.Based on Park-Ang damage model,superstructure damage index was defined.Damage performance for the single story single-direction eccentric isolated structure under near-fault and far-source long-period ground motions is evaluated by using elastic-plastic time history analysis.The effects of key parameters on seismic responses for the isolated structure were investigated.It is concluded that damage index values for the isolated structure under long-period ground motions are higher than basic design ground motions,and the structure will failure if the isolation ditch distances are improperly set.The lateral-torsion coupling for the isolated structure had adverse effect on the superstructure damage.Designing aproper isolation ditch distance can protect the structure from failure with the rare seismic case.