Failure issues of brick masonry

This paper focuses on the fundamental meso-mechanical failure processes in masonry prisms when composite cl\ay bricks bonded by cement mortar are subjected to axial compression. There are several intriguing issues which complicate the failure of the masonry composite because of the subtle interaction effects between the clay brick units and the weaker cement mortar. In fact, 3-D analysis is required to fully penetrate the failure mode which is governed by biaxial tension-compression of the solid brick rather than triaxial compression of the mortar. Dimensional reduction in the form of 2-D plane stress analysis leads to erroneous mode conversion and to significant underestimation of the compression capacity of the masonry prism which depends primarily on the tensile strength of the brick unit. In other terms, the out-of-plane confinement plays a critical role in the assessment of the overall compression capacity of masonry walls.