Seismic Collapse Study Of Masonry Structures Baced On Fragility

Masonry buildings account for a large proportion in China's urban and rural areas,and the study on seismic performance of masonry structures has very important practical significance for new Masonry structures and reinforcement of existing structures.Discrete element method is a recently developed new analytical method, with the theoretical basis of Newton's second law. This method reaches equilibrium through iterative calculations of interactions between each other. The calculation does not require displacement conforming, can simulate structure's performance with large deformation. In this paper, a calculation program about extended discrete element method (EDEM) has been programmed by MATLAB programming, and the results were coMPared with the experimental results, which were proved well. Nine masonry walls in a three-story structure and twelve walls with the parameters adjusted were analysed by using the program and the skeleton curves have been got. By comparing the analysis results, the influences on the wall lateral capacity and deformation performance about material strength, constructional columns and the vertical stress has been found. Through fasculation of all the walls each layer, the Tri-Broken line model of Elastic-plastic restoring force curve were obtained.The theory and implementation steps of incremental dynamic analysis (IDA) was introduced, selected suitable inter-story shear model for masonry structures and ten seismic signals to analyze seven masonry structures with different materials strength, different layers, different proportion of constructional columns by using IDA, with the basis of elastic-plastic restoring force curve by EDEM program. A number of IDA curves and performance points at different quintiles by statistical analysis. Through the comparison analysis of seven IDA curves, the impact of material strength, layer and the set number of constructional columns on the seismic performance of masonry structures has been found.The theory and implementation steps of Seismic Vulnerability Analysis have been described. Applied IDA method to Seismic Vulnerability Analysis of masonry buildings, and got threshold value of the limit state. Seismic vulnerability curves of 7 building were obtained, and the fitting equations were got. Based on the analyses of the data obtained, we got the seismic performance and characteristics of masonry structures with different parameters. And be able to give an intuitive probability of slight damage, serious damage, and complete destruction of masonry structures with different parameters and obtained structure characteristics under different performance level.