近断层水平-竖向地震作用下基础隔震结构的动力响应

DYNAMIC RESPONSES OF BASE-ISOLATED STRUCTURE UNDER THE NEAR-FAULT HORIZONTAL-VERTICAL SEISMIC ACTION

基础隔震技术在目前的结构分析和设计过程中,对于冲击性较强的近断层地震作用考虑甚少,特别是竖向分量考虑更少。通过选取1999年台湾集集地震中,含有完整水平与竖向地震分量的近断层记录、远场地震记录以及断层附近非脉冲型地震记录作为地震输入,分析基础隔震结构在近断层水平-竖向地震分量共同作用下的动力响应,以及隔震支座的受力状态。结果表明,脉冲型近断层地震波对中长周期隔震结构的影响较大,最大速度脉冲周期对基础隔震结构动力响应不是绝对控制性因素;近断层地震波竖向分量对基础隔震结构水平向的振动效应影响较小,对隔震支座受力的影响较大,可能导致隔震支座处于不安全的受拉状态,且明显大于非脉冲型地震波的影响。

During the application process of base-isolated technology,which is a generally acknowledged measure to resist the earthquake action and reduce the loss of building structure.But the near-fault seismic action with a strong shock is not taken into account usually,and the vertical component is less especially.Some earthquake acceleration records,which include the complete horizontal and vertical components from Chi-Chi Earthquake in Taiwan,are selected and divided into three types,near-fault,far-field and non-pulse seismic inputs.The dynamic responses of base-isolated structures and the states of base-isolated supports are analyzed under the horizontal and vertical motivations of those records simultaneously.The results show that the impulsive near--fault earthquakes impact on the medium and long-period base-isolated structures strongly.However the maximum velocity-pulse period of the seismic records do not control the dynamic responses of base-isolated structures absolutely.The seismic vertical component influences the horizontal responses of structures slightly.But base-isolated supports can be in the unsafe tension state under the pulse near-fault earthquake action,and stronger apparently than that under the non-pulse one.