Shear Tests on Masonry Elements with Damp-Proof Course Membrane

Abstract

Within the framework of the research project on the shear behaviour of masonry elements (triplets) with a damp-proof course (DPC) membrane placed in the bed joints, load tests on four series of masonry triplets have been completed. Each series consisted of 12 specimens with dimensions of either 290x250 mm (series A, B, C) or 230x250 mm (series D). Each element’s thickness was 120 mm. A DPC elastomer-based membrane was placed in each (10 mm thick) cement mortar bed joint of the specimens of series B, C and D, whilst 12 specimens of series A were built without DPC and served as control specimens. The DPC was placed either in the middle of the bed joint (series B) or between the masonry unit and the bed joint mortar (series C and D). The elements of all series were built using clay bricks, except for series D specimens, for which the outer units were concrete bricks that were used to simulate the concrete slab. Twenty eight days after preparation, the elements were first subjected to a given pre-compression followed by a shear load that was applied in a deformation-controlled manner up to failure of the specimen. Four different levels of pre- compression were considered (0.2 MPa, 0.6 MPa, 1.0 MPa and 1.5 MPa) and for each level three replicates were tested for each series. This paper presents some preliminary results and discusses their significance in relation to current design practice. A number of conclusions as well as recommendations for practical application and future research are given.