Research On Seismic Vulnerability Of Masonry Structure

Masonry is an ancient form of building structure.Owing to the advantages of local material,simple construction,low cost,good thermal insulation properties,masonry structure has been widely used in office building,residence building,school building,hospital building and other construction projects.However,compared with other structure system,its brittle material,low strength,heavy gravity and bad integral performance lead to poor performance under seismic action.All the previous seismic damage data showed that masonry structure has the worst seismic behavior and the most severe damage.Thus through studying of seismic vulnerability analysis,we can get the fragility curves of masonry structure,which can provide references for earthquake disaster assessment of masonry structure.(1)Though analysis of earthquake damage data of masonry structure,this paper systematically elaborated the damage characteristics and analysis the damage reasons.Furthermore,this paper put forward some reasonable suggestions from aspects of seismic design and construction quality.(2)Based on the research of earthquake damage matrix,which formed through the Panzhihua earthquake damage investigation of fortification masonry buildings,through the study of probability distribution function of the earthquake hazard index,the probability of each damage grade was deduced under the seismic intensity for Ⅸ,Ⅹ degrees structure,the research would consummate the earthquake damage matrix of fortification masonry buildings of Panzhihua region and provide data to earthquake damage assessment of fortification masonry buildings in high intensity zones of Panzhihua area.(3)Through analysis statistic data about wall experiments of several research institutions and based on the Lu-Qu restoring force model,the parameters of restoring force model skeleton curve and hysteretic rules were calibrated and the restoring force model of masonry wall was established.Based on the comparison of hysteresis curve of experiment,the applicability of Lu-Qu model was verified.(4)Using three spring element model and finit software MARC for modal analysis,and compared with the results of ABAQUS,ANSYS,Perform-3D,the result is relatively similar to each other.This indicated that using the three spring element model can better simulate the mechanics performance and dynamic characteristics of masonry structure.(5)Based on Lu-Qu restoring force mode,and take inter-story displace as vulnerability damage control index,three spring element model and finit element software MARC was applied to analy seismic vulnerability,and analysis the matric under the action of minor,moderate and major earthquake,the result show that the the code of “no damage in minor earthquake”,“repairable in moderate earthquake” and “no fail in major earthquake” can be reached.(6)In order to study the influence factors of seismic vulnerability of masonry structures,this paper use model of various layer,various bays and various mortar strength for seismic vulnerability analysis,and these influence factors of the seismic vulnerability curve was compared.