An upper-bound rigid–plastic solution for the shear failure of concrete beams without shear reinforcement

Abstract

Synopsis In recent years research workers at the Technical University of Denmark and elsewhere have shown that simple rigid–plastic methods of analysis can be used to predict closely the experimental shear failure loads of reinforced and prestressed concrete beams. The method has proved sufficiently attractive in Europe to be considered as a basis for new code of practice formulations for shear failure, but has so far been rather neglected in the United Kingdom. In this paper, rigid–plastic analysis is applied to the shear failure of reinforced or prestressed concrete beams without shear reinforcement. A new upper-bound solution for this problem is derived and compared with the previous ‘exact’ solution derived by Nielsen and Braestrup. The new upper-bound solution is shown to produce lower failure values of shear stress for certain ratios of compression to tension steel.