Research Of Seismic Vulnerability Of Confined Masonry Buildings

Violent earthquake brought great disaters,and in earthquake the ruin of buildings threatened lives and properties mostly.In order to improve the seismic preformance of masonry buildings,in recent years,confined masonry buildings which shown significant improvement were wildly used.However,all the problems could not be solved and it appeared different level of damege.To have a knowledge of details of how it works and in better sevice of earthquake fortification,in this paper,the vulnerability of confined masonry buildings was studied.the main works are below:1.Grasp the orientation and trend of the study of vulnerability of confined masonry buildings;summary the basic theorial anlysis method——IDA based time history analysis method and PUSHOVER.2.Construction characteristics,failure process,damage levels,factors affecting the seismic performance and types of damage were discussed;hysteretic model used in time history analysis was given;the significance of vulnerability study was proposed through pratical examples of confined masonry buildings damaged in earthquake.3.IDA based time history analysis was carried on 22 models,through which,seismic responses were acquried and further more the vulnerability curves of the 22 models were acheived.The vulnerability curves reflected some characteristic of confined masonry buildings.Firstly,seismic fortification criterion was fulfiled.Secondly,the improvement of seismic performance was limited,for earthquake intensity that 2 degrees higher than fortification intensity,confined masonry buildings were suffering high risk of being ruined.thirdly,factors affectng vulnerability including number of floors,height of floors,strenghen of martor,area ratio of earthquake resistant wall and force ratio of tie columns were discussed and the affecting mechanism was given.and fourthly,the factors of the area ratio of earthquake resistant wall and force ratio of tie columns were emphasized by keeping other factors unchanged,and in this section,an conclusion that tie colunms contribution to shear capacity should be taken into account was draw.Along these analysis,index of vulnerability assessment was given.4.Based on index of vulnerability assessment and intensity correction factor,simplified vulnerability analysis methods of individuals of confined masonry buildings was proposed.The relation of area ratio of earthquake resistant wall and force ratio of tie columns to damage levels was given.Based on the distribute of earthquake resistant wall and force ratio of tie columns of confined masonry builds,simplified vulnerability analysis methods of area of confined masonry buildings was proposed...