This thesis presents a new numerical model based on a combined finite-discrete element method, capable of predicting the behaviour of masonry structures under static, dynamic and seismic loads. A new numerical model of steel clamps and bolts in dry stone masonry structures is implemented in the available numerical cod Y-2D based on combined finite-discrete element method. Model includes several types of clamps and bolts which are frequently used in strengthening of dry stone masonry structures taking into account influence of the pulling out of the clamps and bolts from the stone block, cyclic behaviour, yielding and failure of the steel. The verification of the model and possibility of using this model in incremental dynamic analysis of real dry stone masonry structures is also shown. New material model for numerical analysis of unreinforced masonry structures was also developed. Model consists of new numerical model in contact element which simulates connection between block and mort, and new material model in finite element. Material model in finite element takes into account orthotropic behaviour, cyclic behaviour, possibility of failure and softening in pressure. Numerical model of contact element which simulate connection between block and mort take into account possibility of failure and softening behaviour in tension and shear, increasing of fracture energy in shear due to increasing precompression stress, decreasing friction coefficient due to increasing shear displacement as well as cyclic behaviour connection between mort and block. The verification of the model was performed on examples by comparing it with the results obtained with the known numerical and experimental results from literature. New numerical model for seismic analysis of reinforced masonry structures was also presented. Model consists of synthesis of new developed material model for unreinforced masonry structures and previously developed numerical model for analysing reinforced concrete structures.