Numerical Simulation of In-Plane Loaded Unreinforced Masonry Walls Based on Homogenized Discrete Element Model

Abstract

This study established homogenized discrete element model of unreinforced masonry walls. In this model masonry was divided into rigid bodies connected by normal and shear springs. These springs represented the mechanical behavior of bricks/blocks and mortar synthetically. The constitutive relations and failure criteria of springs were obtained from masonry material experiments. Dynamic relaxation procedure was adopted for the solution of numerical simulation. The model was used to simulate the in-plane loading experiments of unreinforced concrete perforated brick walls conducted at Tongji University. Simulated crack patterns, crack loads, crack deformations, load-deformation skeleton curves, ultimate bearing capacities and ultimate deformations were compared with experimental results and it was verified that the homogenized discrete element model was efficient to simulate the in-plane properties of unreinforced masonry walls both in continuous deformation and failure phase. Through parameter study, it was also indicated that the larger masonry strength and vertical pre-compression stress in a certain range would cause the increase of the in-plane capacity for a masonry wall and the larger height-width ratio would cause the change of crack and failure pattern from shear to flexure.