Experimental and numerical research into local contact effects in masonry

Masonry is a compilation of units and mortar. The mortar joins the units together and allows for dimensional tolerances in the bricks. Ideally, the mortar joints are completely filled and consequently stresses are transmitted uniformly through masonry. However, sometimes only the joint-edges may be filled like in shell bedded masonry. This causes irregularities in the stress distribution. Another situation with local contact effects where stresses are not uniformly distributed, is the wall-floor connection when bearing strips are applied. These strips are intended to concentrate the loads from the floor in the centre of the wall allowing for more rotation of the floor and to increase the axial load bearing capacity of the wall. Parameters like the joint filling ratio in shell bedded masonry or the width and position of a bearing strip affect the load bearing capacity of a wall. To study the effects of such local contacts, experiments and numerical simulations of these experiments were performed. Variation of material properties, inevitable in experiments, is taken into account in the simulations. Cracking processes are simulated by using sequential linear analysis techniques. Relationships between load bearing capacity and the main parameters were established. Keywords : floor-wall interaction; compression; stress distribution