Simple Homogenized Numerical Model for the Analysis of Multi-leaf Masonry Walls

A simple numerical model for the analysis of multi-leaf walls is discussed. These are featured rather frequently in masonry buildings across Europe, and are characterized by a low resistance to out-of-plane actions, which often causes the partial or total collapse of the structure. A 2D FE mesh is created directly from the sketch of each wythe, which is later exploited for deriving the 2D homogenized failure surface of the single layers. A weighted average is operated among the homogenized stresses to obtain the failure surface of the multi-leaf wall. Then, the out-of-plane bending moment for each layer is evaluated by assuming a constant distribution of the homogenized stress over the thickness. The overall out-of-plane failure surface in terms of bending moments is then obtained for the whole wall, assuming each layer to behave separately in bending. The model is applied on two walls displaying distinct layouts of units: one presents a running bond masonry consisting of tuff blocks, the other is constituted by randomly-assembled stones. The results show an overall higher resistance of the randomly-assembled wall with respect to the running bond one, both for the in- and out-of-plane behaviors.