汶川地震作用下约束砌体房屋的抗震能力分析

为验证约束砌体结构的抗震性能,取4栋7层砌体房屋为例进行非线性地震反应分析。4栋房屋中2栋(代号为A1、A2)选自汶川地震影响区的约束砌体房屋,另2栋(代号为B1、B2)为虚拟无筋(或非约束)砌体房屋,除了无任何约束作用的构造措施之外,其他都分别和A1、A2相同。分析中选取汶川地震中基岩和土层场地的共20条地震动作为地震输入。基于分析结果,做了两方面的比较:约束砌体结构房屋地震反应特征和汶川大地震现场调查所见的对比和约束砌体房屋和无筋砌体房屋地震性状的对比。主要结论有:①计算得到的约束砌体房屋在大地震下的震害特征和实际地震相当吻合,结构分析所用的计算模型、恢复力模型和参数取值的可靠性得到验证;②和无筋(或非约束)砌体房屋相比,约束砌体房屋使砌体结构的抗震强度和延性大为改善,具有很好的抗倒塌能力。

Seismic performance of confined masonry buildings during the Wenchuan earthquake

To validate the seismic performance of confined masonry structures four seven-story masonry buildings are numerically studied through nonlinear dynamic analysis.In the four studied buildings two are confined masonry structures(assigned as A1 and A2) selected from affected region in Wenchuan earthquake,and other two(assigned as B1 and B2) are fictitious unreinforced masonry structures having the same configuration and other characteristics with A1 and A2 except for in confinement aspect.In the analysis 20 accelerograms on bedrock and soil sites were selected and used as input motions.Two comparisons are made,one for the damage states of the two confined stuctures between the analysis results and the observation from the earthquake investigation,and one between the confined strctures and the unreinforced structures.From these comparisons some interesting conclusions are drawn.