Three sides supported unreinforced masonry walls under multi-directional loading

Interaction curves for masonry walls supported on all four edges subject to multi-directional loading has recently been reported by the authors (Noor-E-Khuda et al., 2018). Load bearing URM walls are generally detailed with vertical control joints (which are structural end where the normal stress vanishes), and non-load bearing walls are likely to have unsupported top horizontal edge. Therefore, three sides supported URM walls are examined in this study. An explicit finite element macro model based on a layered shell element is used in the investigation. A series of interaction curves approximately resembling bilinear domain is developed to represent the response of the one vertical edge unsupported URM walls under multi-directional loading. The interaction curves for the top horizontal edge free walls showed a trilinear approximation. Influence of the boundary conditions and the level of out-of-plane loading to the shape of the interaction curve have been examined. It is shown that the in-plane capacity reduces rapidly beyond a critical out-of-plane load level; therefore, disregarding the multi-directional loading interaction could be unsafe. A simplified non-dimensional expression proposed by the authors for the interaction curves of four sides supported walls is extended for the three sides supported walls in this paper. © 2018 Elsevier Ltd