Proposal for improving the solid clay brick contact surface to increase the initial shear strength of masonry

Abstract

Under normal service conditions, masonry is mainly subjected to the action of gravity loads, however, under the action of seismic loads, masonry is subjected to the combined action of vertical and lateral forces which develops a biaxial stress state and generates considerable shear stresses at the brick/mortar joint interfaces. The work of masonry under the action of shear forces parallel to bed joints is widely studied and leading researchers in the field of masonry structures have studied the behaviour, constitutive models, failure criteria and numerical models of masonry, however there are almost not studies on the influence of the horizontal contact surface of bricks on the initial shear strength of masonry. This work proposes a slight modification of the horizontal contact surface of solid brick to increase the initial shear strength of the masonry. The experimental proposal consists of drilling superficial blind holes with a depth of 6–8 mm with an overall drilled area of 10–13% of the horizontal surface of the brick. The arrangement of the holes is such that main difference with similar proposals is that the central part of the brick remains unaltered. Experimental results show that this proposed modification of the brick increases the initial shear strength by about 45% and allows the development of the plastic deformation phase, which is an important improvement for the structural behaviour of masonry structures under the action of considerable lateral forces.