强震作用下竖向不规则RC框架结构抗震易损性分析  

Fragility analysis of vertically irregular reinforced concrete frame structures subjected to pulse-like ground motions

作　　者：周靖[1] 罗高杰[2] 方小丹[1] 

机构地区：[1]华南理工大学亚热带建筑科学国家重点实验室,广东广州510641 [2]湘潭大学土木工程与力学学院,湖南湘潭411105

出　　处：《建筑结构学报》2011年第11期134-142,共9页Journal of Building Structures

基　　金：亚热带建筑科学国家重点实验室基金项目(2010KB13);教育部博士点基金项目(20094301120001)

摘　　要：研究速度脉冲强震作用下竖向不规则钢筋混凝土框架结构的抗震易损性。以5层和10层底层竖向不规则框架结构为分析对象,考虑地震动输入的不确定性,通过非线性动力时程分析获得结构底层最大层间位移响应,并通过曲线拟合建立最大层间位移与基本自振周期对应的谱加速度函数关系;假定最大层间位移和极限性能目标位移取对数正态分布的平均值,建立能有效评估结构竖向不规则极限控制参数的易损性曲线。分析结果表明:速度脉冲强震作用下,楼层承载力和刚度突变对结构层间位移有较大影响,底层竖向不规则程度越大最大层间位移亦随之增大,而中间层最大层间位移则减小;地震动强度越大,最大层间位移离散性越大;楼层承载力和刚度突变对抗震易损性曲线的影响较大,楼层数不同结构易损性曲线趋势不同。This paper addressed the seismic vulnerability of vertically irregular reinforced concrete structure subjected to velocity pulse-like ground motions.Employing a 5-story and a 10-story frame structure with vertical irregularities at the first story and considering the randomness of input ground motions,the maximum inter-story displacement demands of the first story were obtained by nonlinear dynamic time history analysis and were related to spectrum acceleration of the fundamental vibration period by curve fitting method.Logarithm normal distribution was assumed for the maximum inter-story displacement demands and limit performance target displacement,the seismic fragility curves for evaluating the irregular limit parameters were produced.The results show that strength and stiffness irregularities have important influence on the structural inter-story drift under different strong velocity pulse-like ground motions.The maximum inter-story drift at the first story increases with the increase of the degree of irregularity,whereas the maximum inter-story drift at the middle story decreases.The dispersion of the maximum inter-story drift increases with the increase of ground motion intensity.In addition,strength and stiffness irregularities also have significant influence on the seismic fragility curve.The shape of the fragility curve varies due to the different number of story.

关 键 词：框架结构 竖向不规则 速度脉冲地震 数值分析 易损性分析 

分 类 号：TU375.4[建筑科学—结构工程] TU352.11