Empirical Mohr-Coulomb Failure Criterion for Concrete Block-Mortar Joints

Modified values for the shear bond strength and coefficient of friction in a Mohr-Coulomb type of failure criterion for concrete block–mortar joints in masonry are calculated using finite-element analyses in which it is assumed that the state of stress in the joint is nonuniform. The failure loads used in these analyses are obtained from three laboratory specimens. It is shown that the shear failure in concrete block–mortar joints in masonry can be conveniently described by a single expression that has some dependence on the modulii of elasticity of concrete blocks and joint mortar. The modified values of the parameters in a Mohr-Coulomb equation are verified by their successful ability to estimate failure loads in two additional laboratory specimens.