Study On Failure Mode Of Masonry Structures Under Strong Ground Motion

Masonry structures are widely used in China’s countryside, because are obtainedeasily and cheap, and possess the characteristics of good fire resistance, durability andeasy construction. However, the seismic performance of masonry structures is poor. OnMay12,2008in Wenchuan earthquake, it’s more serious damage appears in masonrystructures compared to other structural forms of construction, which resulting in heavycasualties and huge economic losses. Therefore, how to improve the seismicperformance of masonry structures, and make more study on the failure mode is verynecessary.ABAQUS finite element software is used to design a series of examples ofmasonry structures through the combination of actual earthquake damage of masonrystructures. To analyze the seismic performance from the displacement reaction anddeformation capacity, and to study the masonry structure the failure mode from thecrack degree of injury. The main results achieved are as follows:①When the stiffness ratio of window wall to spandrel wall is larger, the structureis more likely to occur undermine at spandrel wall with weak stiffness relatively. Thedestruction of the wall under window dissipates the energy, and it can reduce thedamage to the walls between windows which are as a load-bearing walls. Compared tothe ratio that is small, the damage of the structure is less. This could improve theseismic performance, and shows a more ductile nature.②Masonry structures which are built with constructional column is better thanwhich built without constructional column, and the damage level is better than thestructure which do not contain constructional column. That because the spaceconstraints system which is formed by constructional column and ring beam enhancesthe integrity of structures.③With the improvement of mortar strength, the tensile and shear capacity arealso improving, and with the improvement of mortar strength, it can significantly delaythe cracking moment of the spandrel wall.④When a hole is open in masonry structure wall, it weakens the section stiffnessof the wall and the restrict of the concrete constructional column to the structure, andthe bearing capacity of the entire structure decreased significantly. Increasing ofopenings rate does not mean that structural damage is larger than the openings rate is small, this depends on the model of opening holes of the masonry structure. This isbecause when the opening rate increases, the stiffness of the structural will decrease,compared to the decreasing of the window wall’ stiffness, the spandrel wall’ stiffnesswill decrease more. Above all, the structure containing large opening rate is more likelyto damage at spandrel wall.