Accurate Estimation of Interface Shear Stresses in Composite Masonry Walls

Abstract

A composite masonry wall consists of a concrete‐block wythe, a clay‐brick wythe and a cavity (i.e., collar joint) between the two wythes that is filled with mortar or grout. The in‐plane loads on a composite wall due to gravity and/ or wind are generally applied on the block wythe and can produce large interface shear stresses in the collar joint. The composite action of the wall is ensured only if these shear stresses are less than the shear strength of the interfaces. A refined finite element procedure based on interface shear stiffness and considering stress singularity, which can accurately predict collar‐joint interface shear stresses in composite masonry walls, is proposed in this paper. This paper shows that there is no need to consider reduced shear stiffness for the interface elements. Additionally, accurate shear stresses at a collar‐joint interface can be obtained for discontinuously applied loads by disregarding stresses in the two elements closest to the point‐of‐stress singularity. Use of the proposed model permits accurate assessment of the interface shear stress in the collar joints of composite masonry walls.