Effect of Side Slopes on Concrete Bearing Strength

The problem of large forces acting over limited contact areas of concrete is one of frequent occurrence in engineering deign. In three earlier papers, the effect of several important variables on concrete bearing strength was considered in some depth. However, the specimens reported therein and elsewhere by other authors were all of uniform cross section with vertical sides. In practice, instances also occur where the sides of the supporting members are sloped from the loaded ends. Typical examples are: concrete rocker bearings; piers; footings; and sometimes the end blocks of prestressed concrete elements. Little data are available on the bearing strength of splayed specimens or specimens of variable cross section in the transfer zone of the concentrated load. The present report gives in substance the test carried out by the writer on plain concrete blocks having two or more sloped faces and loaded through bearing plates of various sizes and shapes.