Study On Seismic Vulnerability Of Masonry Structure Considering Wall Openings

The grief that Wenchuan earthquake produced haven’t healed,Ya’an earthquake caused great damage to the people in the disaster area. In China,as one of the most frequent earthquake countries,there are a number of masonry structures in different seismic regions,and the masonry structure is the most vulnerable in earthquakes,so we should pay a great attention to the seismic of masonry structure all the time.In this paper,tests of two exiting masonry walls under cyclic loads were simulated by the concrete damage plasticity model of the finite element software’ABAQUS’to verify the applicability of the software.Then,21piece of masonry wall models were set up by ABAQUS,from the perspective of openings ratio,openings position,number of openings,structural measure and aspect ratio and so on,the Force-Displacement curves of the masonry walls under vertical uniform load and monotonic horizontal load were established,and the seismic performance of masonry walls was analyzed including the ultimate bearing capacity, stiffness degradation characteristics, displacement ductility and so on,then to get the seismic performance of masonry walls with opening influenced by different factors.Then,four transversal bearing wall system three-level masonry buildings in the8degree area were established with the consideration of the cross wall openings rate. The restoring force models of masonry walls were simplified by finite element analysis,and the recovery models of the wall were overlaid to get the restoring force model of the shear frames.10ground motion records with the same earthquake groups and the same type of site were selected,and the IDA analysis of the structures was made by a MATLAB program.The IDA curves of16%,50%,84%percentile were drew in order to get the seismic performance of masonry structures according to the50%curve.Based on the results of IDA analysis, the seismic vulnerability of those4masonry structures was analyzed to get the seismic fragility curves in different properties.Under different intensity,the seismic collapse probability of masonry structures under rare occurrence earthquakes and great earthquakes was picked up from the IDA curves.At last,some suggestions about the openings rate of the bottom cross wall were proposed for collapse performance of three-level masonry buildings under different intensity.