JAN KUBICA Silesian University of Technology, Gliwice, Poland

The problems of analysis of stiffening walls of buildings are connected with shearing in the horizontal and vertical directions. Protection of buildings against vertical shear loads is still not well understood. This kind of shearing is the dominant load where there is nonuniform ground displacement, for example caused by mining subsidence. The behaviour of unreinforced masonry walls subjected to shear and compression loads in the vertical direction, has been analysed. Clay brick and aerated concrete block walls have been tested. The significant influence of the compression stresses ol on shear strength tv has been obtained. An empirical relationship for tv as a function of oe is proposed and compared with the experimental results.