Bearing Strength of Concrete—Geometric Variations

Although the problem of large concentrated forces acting over limited areas occurs in almost all phases of concrete construction, only limited experimental results are available on the ultimate bearing capacity of concrete and the various factors affecting it. The well-known cube root formula for local pressure, as recommended in various codes of practices, is based on a limited number of tests on sandstone cubes by Bauschinger. Because of the overall complexity of the problem and the difficulty of arriving at an accurate theoretical solution, experimental studies are imperative. In the present report tests concerning the geometrical variations, i.e., relative dimensions and shape of loaded area—strip, rectangular, and square, height of specimen and eccentricity of loading—uniaxial and biaxial are presented. Based on extensive tests, equations and diagrams are obtained for deriving the local bearing strength of concrete in terms of the cube compressive strength of concrete.