Influence of brick-mortar interface on the mechanical behaviour of low bond strength masonry brickwork lintels

A study of the influence of the brick-mortar interface on the pre- and post-cracking behaviour of low bond strength masonry wall panels subjected to vertical in plane load is presented. Using software based on the Distinct Element Method (DEM), a series of computational models have been developed to represent low bond strength masonry wall panels containing an opening. Bricks were represented as an assemblage of distinct blocks separated by zero thickness interfaces at each mortar joint. A series of sensitivity studies were performed supported with regression analysis to investigate the significance of the brick-mortar interface properties (normal and shear stiffnesses, tensile strength, cohesive strength and frictional resistance) on the load at first cracking and ultimate load that the panel can carry. Computational results were also compared against full scale experimental tests carried out in the laboratory. From the sensitivity analyses it was found that the joint tensile strength is the predominant factor that influences the occurrence of first cracking in the panel, while the cohesive strength and friction angle of the interface influence the behaviour of the panel from the onset of cracking up to collapse.