A calibration of a numerical model for analysis of masonry walls with application to experimental results is presented in this paper. The experimental results used for calibration are derived from the research project "Optimization of shape of masonry units and technology of construction for earthquake resistant masonry buildings" conducted by Bosiljkov and Tomažević in 2005 for ZAG Ljubljana. This paper adopts micro-modelling strategy for analysis of masonry specimen by discrete element method and application of different nonlinear material models both for blocks and mortar. In order to determine the values and to calibrate the necessary material data for the used materials that were not obtained experimentally, several numerical investigations and simulations were performed. Numerical analysis of masonry walls was performed with the use of UDEC software. A comparison of numerical and experimental results as well as a comparison of the failure mechanisms is presented. With the assumed modelling strategy and numerical method, a satisfactory compliance with the experimental results regarding limit state and developed failure mechanisms is obtained. With the results from this research and literature survey several recommendations regarding material properties necessary for numerical analysis are provided in the end of this paper.
