Analysis Of Out-of-plane Performance Of Masonry Walls Based On Discrete Element Method

Under earthquake or the wind action, the walls collapse outside caused the insufficient stiffness, causing casualties and property losses, so it is very important to research the out-of-plane performance of masonry walls. Due to the wall is made up of two phase materials that are bricks and mortar, materials performance difference is larger, and the mechanical performance is extremely complex due to the heterogeneity the wall. In the nonlinear analysis problems often appear, such as failure criterion definition difficult, slow convergence speed, and even no convergence, the usual approach is that block and mortar are homogenized to one material(RVE), and it is only a rough approximation. The approach is suitable to macro model, and for single wall need to be more subtle way. It should be considered the interaction between block and mortar and the influence of material differences.The rock mass structural plane become weak layer, the mortar layer is similar to that in masonry structure. The mortar layer and contact surface of mortar and blocks are the most prone to damage in masonry structure. In this paper, the masonry structure was analyzed using the discrete element method that was used to rock mechanics, the mortar and blocks were modeled in the state of separation, the contact surface between mortar and blocks was simulated like a rock joint surface. Based on the principle of discrete element method, masonry wall was studied in out of the plane performance, to carry out the several aspects work as following:1)The unreinforced wall that was tested by Griffith professor at the university of Adelaide was simulate din discrete element method. By contrast, the results of numerical analysis and experimental results validate the rationality of modeling method, material parameter definition and failure criteria.It provides evidence to qualitative analysis of various parameters that can have an influence out-of-plane mechanical performance on the masonry wall.2) Studying the geometric parameters and material parameters that how to influence on out-of-plane mechanical performance on the masonry wall, to set up different high thickness ratio, vertical pressure and aspect Ratio of numerical model. The out-of-plane mechanical performance of masonry wall was analyzed, to acquire the wall of the ultimate load and failure mode.3)The reinforced masonry wall are analyzed in numerical simulation, and the ultimate load and ductility of the reinforced wall was comparative to unreinforced wall. The role of reinforcement was explained in reinforced wall. It was analyzed the influence of different reinforcement ratio, different reinforcement to reinforced masonry wall, such as wall bearing capacity, cracking load and the failure process. The reasonable reinforcement ratio of the wall and the optimal way of reinforcement were put forward.