Numerical Modelling of an Unreinforced Masonry Wall with Central Window Opening

Unreinforced masonry (URM) structures comprise over 60% of the building stock of India. URM structures are highly vulnerable under earthquake loads. Their seismic behaviour is complex due to the nonlinear and composite nature of masonry which comprises brick units, mortar, and the unit–mortar interface. Experimental studies on URM walls with openings are inadequate with varying experimental procedures. In this paper, in-plane pushover loading is applied on a two-dimensional unreinforced masonry wall with a central window opening. For modelling bricks, three material models are used, namely the linear elastic model, the engineering masonry model, and the total strain crack model. For modelling the interface, four approaches are used, namely the linear elastic model, the combined cracking-shearing-crushing plastic material model, the Coulomb friction model, and the no-tension nonlinear elastic model. The pushover curves indicate the significant impact of the opening on the capacity of the URM wall. The stress contours obtained from the various methods predict the crack pattern and modes of failure. These results are analysed to discuss the effect of the material models and interface properties on the results obtained from the numerical modelling. The results indicate that the selection of the micro-modelling technique for numerical modelling of URM walls has a significant influence on the observed strength, stiffness, and ductility characteristics.