Discrete element modelling to predict failure strength of unreinforced masonry walls

Abstract

Similar unreinforced masonry (URM) buildings are found in Australia and New Zealand due to the two countries’ shared history of European settlement. It is known that there is a large inventory of URM buildings in both countries and that these buildings are potentially earthquake prone. Therefore, an understanding of their behaviour when subjected to earthquake loading is needed. The Discrete Element Method (DEM) is an advanced modelling technique that can accurately predict and simulate collapse mechanisms in a realistic way. In the reported study the DEM was applied using a micro-modelling approach to simulate walls tested in the laboratory. Solid rigid elements were used to represent the distinct brick units and an inelastic law was assigned to the contact surfaces to simulate the mortar between the bricks. In previous work two groups of walls were tested. First, full-scale walls with different configurations were subjected to quasi-static face loading imposed by a system of airbags. Secondly, five reduced scale walls were built for shaking-table testing. Nonlinear static (pushover) analysis was conducted to simulate the first group of walls of the experimental campaign. In addition to the wall simulations, simple brick and mortar numerical models were generated and analysed for calibration purposes.