DESIGN OF HIGH-PERFORMANCE CONCRETE CORBELS

Currently, concretes of higher compressive strengths have been produce d and increasingly used by designers and contractors for both reinforc ed and prestressed concrete construction. The design of concrete corbe ls using the strut-and-tie model considers two failure modes: failure by crushing concrete in the strut and by yielding of the main steel re inforcement. To consider die failure by diagonal tension, a third equa tion is included in the truss plastic model proposed by Rogowsky and M acGregor. To use the truss plastic model, an efficiency factor is appl ied to reduce the effective concrete strength. An efficiency factor is proposed in this paper for high performance concrete. The proposed mo del using the new efficiency factor gives an improved correlation with experimental data. Based on the test results reported from literature review, the design method proposed by AFREM for high strength concret e corbels is modified in this paper to make design of high strength co ncrete corbels more reasonable. The comparison with experimental data shows that the modified AFREM model predicts fairly well the shear cap acity of the corbels.