Moment redistribution in reinforced concrete beams

Abstract

Structural engineers have long recognised the importance of ductility in the design of reinforced concrete structures and, as a consequence, the importance of the ability of a reinforced concrete member to redistribute moment to give prior warning of failure, adjust the structural response to allow for variations in applied load and column drift, and to absorb energy during earthquake, blast and other dynamic loadings. Quantifying the ability of a member to redistribute moment, which at first sight appears to be a relatively simple problem, has been difficult and the problem is still unresolved as can be seen by the very wide range of permissible moment redistribution values in national standards. In this paper, established techniques of shear friction, partial interaction and rigid body displacement are combined to develop a novel structural mechanics based mathematical model for moment redistribution that can be applied to any member with any material property such as the use of brittle reinforcement.