The influence of vertical load on shear failure in concrete block work construction

Abstract

This masonry research investigates the influence of vertical load on shear failure in concrete block work construction. Through research has been done on this subject to serve as a background and reference for the laboratory testing. It consisted of investigations on concrete masonry shear walls with varying physical parameters like dry jointed walls, mortared joint, concrete/grout infilled masonry and concreted and reinforced masonry walls. A series of tests was carried out a the structural laboratory of the Faculty of Architecture and Civil Engineering at the University of Malta. The tested samples consisted of three block prisms arranged vertically and constructed with dry and fibre board joints. All samples were tested for ultimate compression and for shear resistance by mobilizing the middle units of the prisms. The shear tests were carried out for different vertical loads factored from the ultimate compressive resistance of the masonry prisms. The results were investigated by means of superimposed graphs for each wall type and consecutively the results between the fibre board and the dry jointed prisms were compared and a behaviour pattern was concluded on the criterion of Coulomb's Friction Law. The main objective of this dissertation was to investigate the influence of the vertical load on the modes of failure exhibited in masonry walls when shear loads are applied. Also the shear resistance of masonry was determined with the aid of Mohr-Coulomb Criterion and Mohr Circle diagrams, form which failure envelop, the angle of friction and finally the friction coefficient where found.