Simulation of in-plane shear test on masonry walls using micro modeling tecniques

Abstract

A series of experimental tests involving in-plane shear loading of masonry walls is numerically simulated using finite element detailed micro models. The experimental tests were performed on masonry walls composed of solid clay bricks and cement/lime mortar. The mechanical properties of the two constituent materials and the brick-mortar interface had been previously characterized. The walls were subjected to shear under varying levels of uni-form vertical pre-stress. The finite element models are created by modeling the bricks, mortar and the brick-mortar interface separately. In this manner the failure due to shear, tension or compression can be modelled in each component individually. Nonlinear constitutive laws to model cracking under tension and yielding under compression are used for the continuum elements modelling the units and the mortar. For the tension and shear failure of the interfaces a friction-tension cut off model is employed. Good agreement is found between the experimental and three-dimensional numerical results. The maximum load is well approximated for the entire range of vertical pre-stress level, re-sulting in a realistic numerically derived interaction diagram between vertical compression and maximum shear. Furthermore, an obvious shift is noted in the failure mode produced by the models which mirrors the modes observed in the experiments: failure of the interfaces for low vertical loads and failure of the mortar and the bricks for high vertical loads.