7度区底部局部框架-砌体房屋抗震性能分析

Analysis on seismic performance of masonry buildings with partial RC frames and masonry walls in bottom floor in seismic intensity 7

我国7度抗震设防区中小城镇存在大量底部局部框架-砌体房屋,其底部局部RC框架+砌体抗震墙的布置形式不符合《建筑抗震设计规范》(GB 50011—2010)对7度区底部框架-抗震墙房屋的要求,考察其震害、刚度比及抗震性能有助于指导工程设计。分析了底部局部框架-砌体房屋的震害;设计了5个算例,包括2个底部局部框架-砌体房屋、1个砌体房屋及2个底部框架-RC抗震墙砌体房屋,对比分析了各算例在7度多遇地震下的弹性及罕遇地震下的弹塑性地震反应,考察了层间位移角、应变、耗能等指标。对比分析表明底部局部单排柱框架-砌体房屋,其刚度比、弹性及弹塑性地震反应与砌体房屋接近;底部局部双排柱框架-砌体房屋刚度比、弹性、弹塑性地震反应均大于砌体结构,但小于底部框架-RC抗震墙砌体房屋,其弹性、弹塑性地震反应均满足抗震规范中底部框架-抗震墙砌体房屋的相关设计要求。

There are a mount of masonry buildings with partial RC frames and masonry walls in bottom floor in undeveloped medium and small towns which seismic precautionary intensity is 7.For such layouts in bottom story are not allowed in Code for seismic design of buildings(GB 50010—2010),it is necessary to investigate the seismic damage,stiffness ratio and earthquake performance of such buildings.Earthquake damage of the masonry structure with RC frame and masonry in bottom was analyed,then five samples were designed,which concluding two masonry buildings with partial RC frames and masonry walls in bottom floor,one masonry building and two masonry buildings with RC frames and RC walls in bottom floor,elastic earthquake response under frequently earthquake intensity 7 and the elastic-plastic response under rarely earthquake intensity 7 of the 5 models were conducted,and story drift,strain and energy dissipation are contrasted.Analysis shows that,the stiffness ratio,elastic and elastic-plastic seismic responses of masonry building with partial RC frames of single row columns and masonry walls in bottom floor are similar with masonry structure.The stiffness ratio,elastic and elastic-plastic seismic responses of masonry building with partial RC frames of two row columns and masonry walls in bottom floor are more than masonry buildings,less than masonry buildings with RC frames and RC walls in bottom floor,and can meet the requires for masonry structure with bottom RC frame-shear wall regulated in Code for seismic design of buildings(GB50011—2010).