Failure Criteria for Masonry Panels under In-Plane Loading

Failure of masonry panels under in-plane loading can be attributed to three simple modes: slipping of mortar joints, cracking of clay bricks and splitting of mortar joints, and middle plane spalling. In this paper a suitable strength criterion is connected to each collapse mode. In more detail, a frictional law is associated with the slipping, which accounts for the shear strength depending nonlinearly on normal stress (modified Mohr-Coulomb criterion of intrinsic curve). Splitting can be expected by the maximum tensile strain criterion (Saint Venant), orthotropic nonsymmetric elasticity being assumed for the material. Eventually panels exhibit spalling when the maximum compressive stress (Navier criterion) is attained under biaxial loading. Strength parameters are then identified on the basis of experimental results and a comparison with the reliable criteria found in the literature is carried out. The validity of the proposed failure criteria to predict the experimental failure modes in a nondimensional...