Seismic Collapse Study Of Masonry Walls And Structures

At present, the most common form of building in rural area is the masonrystructure. In all the previous earthquakes, the most prominent collapsed building isthe masonry structure. Therefore, it’s of great significance to study the collapsecapacity of masonry building. In this thesis, based on the idea of component to thewhole structure, fifteen walls with different seismic fortifications are studied bynumerical simulation method while eight masonry buildings with different tectoniccolumns allocation proportion are discussed by increment dynamic and seismicfragility analysis method. This study may have some practical guidance significanceof the design and reinforce of the masonry components and structure.In this thesis, explicit algorithm of LS-DYNA and implicit algorithm of ansys areused to do numerical simulation of the fifteen walls. Nine tested walls’ simulationresults are compared with the tested results to verify the accuracy of finite elementparameters. Vertical pressure, loading regime, aspect ratio, hole ratio and tie columnsare introduced to study the collapse capacity of masonry walls. Also, the superiorityor inferiority of explicit and implicit algorithm are compared.Choose a three story masonry building in the8degree seismic intensity area,using the explicit algorithm of LS-DYNA, the spine curves of load bearing cross wallsare obtained. Add all the spine curves of each layer’s load bearing cross walls.changethe tie columns ratio and story number, eight restoring force models of masonrybuilding can be got. Twenty seismic records and MATLAB program are used to do theIDA analysis. Dispose the IDA results, three curves of16%,50%,84%may beobtained. Finally, the preparation of seismic fragility analysis can be made by the IO,CP, GI points of50%curves.Seismic fragility analysis theory and steps are introduced in the forth chapter.According to the results of IDA, the probability function of each building isestablished and then the collapse probability of the eight masonry building under rareseismic and great seismic in different degree of seismic intensity are obtained. Somereference ideas of tie column ratio for three and seven story masonry building indifferent seismic intensity area are put forward.