Synopsis
Tests of a new type are described in which reinforced concrete plate specimens are cracked in direct tension. The tensile force is maintained while in-plane shear forces are applied across the crack. Measurements are taken of the shear stiffness and subsequent crack widening, together with the tensile forces in the reinforcement, using strain gauges embedded within the bars. A technique of resin injection is used to study the variation in the width of a crack beneath the surface of the concrete. Contrary to the results of previous studies, no significant variation was observed. The shear stiffness of cracked reinforced concrete specimens was compared with results from previous aggregate interlock and dowel action tests. It can be predicted from available theoretical models, provided that the anchorage stiffness of the reinforcement is known.
