On the out-of-plane flexural design of reinforced masonry walls

Abstract

Out-of-plane flexural capacity of masonry is enhanced due to the presence of vertical compression up to a certain level. Most international design standards include the vertical load contribution to the flexural capacity of unreinforced masonry walls; however, the treatment of reinforced masonry design in such standards ranges from completely disregarding to partly accounting for the effect of vertical load to the resistance of out-of-plane loading. Furthermore, consideration of the effects of aspect ratio and boundary conditions on the out-of-plane response of reinforced masonry amongst the design standards is also not consistent. This paper presents a series of studies on the sensitivity to vertical compression, aspect ratio and boundary conditions of the out-of-plane flexure of reinforced masonry walls using a recently validated explicit finite element (EFE) model and provides a comparative assessment of the results predicted from the EFE and provisions of four international design standards. It is shown that disregarding the vertical load makes predictions of two-way out-of-plane flexural response extremely conservative in some standards; however, prediction of one-way vertical bending is reasonable in all standards. The results suggest that there exists a strong case for including the aspect ratio, boundary conditions and vertical compression for appropriate two-way bending design of reinforced masonry walls subject to out-of-plane loading.