Hypothesis for Shear Failure of Brickwork

The validity of the concept that the shear strength of brickwork depends on a combination of the bond shear strength and frictional resistance in the mortar layers is questioned on account of inconsistencies revealed by earlier series of experiments. As an alternative approach the writers suggest that the shear strength may be dependent on the tensile strength of the mortar layers. Assuming that failure occurs when the principal tensile stress in the mortar equals its tensile strength, finite element stress analyses are conducted to determine the maximum principal tensile stresses in brickwork triplets resulting from applied shear and normal compressive forces. Failure curves are constructted relating the theoretical shear strength and normal compressive stress on the triplet for different modular ratios. Experimental results of shear tests on brickwork triplets, with varying normal compressive stress, are compared with the corresponding theoretical curve to provide support for the writers' proposition.