【摘要】 研究速度大脉冲地震作用下结构底层刚度、强度以及两者组合竖向不规则剪切型结构的抗震位移延性需求。选取8条近断层速度大脉冲地震记录,以集中质量剪切型多自由度模型结构为分析对象,通过非线性动力时程分析,研究速度脉冲地震效应和底层竖向不规则综合不利条件下,结构抗震位移延性需求及其沿楼层分布模式的变化规律。分析结果表明:速度脉冲地震作用下竖向不规则结构有更大的位移延性需求;底层强度不规则比底层强度和刚度组合不规则对结构最大层间位移延性需求的影响大,底层刚度不规则时位移延性需求表现出不同的规律;单独减小底层强度或同时减小底层强度和刚度均会增大结构底层位移延性需求而削弱其他楼层位移延性需求,而单独减小底层刚度会使所有楼层位移延性需求均有不同程度的减小。更多还原

【Abstract】 This paper analyses the seismic displacement ductility demand of structures,which have vertical irregularities in strength,stiffness and combined strength-and-stiffness irregularities in first story and are subjected to velocity pulse-like ground motions.Based on lumped mass shear-type multi-degree-of-freedom models and 8 near-fault pulse-like ground motions,nonlinear dynamic time history analysis was performed to these structures.The structural displacement ductility demand and its distribution mode were studied considering velocity pulse effects and vertical irregularities.The results demonstrate that the displacement ductility demand is larger in these structures when considering velocity pulse-like effects.Meanwhile,the influence of strength irregularities on the maximum inter-story displacement ductility demand is larger than that of combined strength-and-stiffness irregularities,and the influence of stiffness irregularities is different.It also shows that singly reducing first story strength or simultaneously reducing first story strength and stiffness increases displacement ductility demand in the first story and decreases it in other stories,but singly reducing first story stiffness decreases all inter-story displacement ductility demand.更多还原