Measurement of Moment Redistribution Effects in Reinforced Concrete Beams

Abstract

Normal practice is to use a linear elastic analysis for calculating the bending moment and shear force distributions in a reinforced concrete structure. This has the virtue of simplicity as well as permitting results from a series of analyses to be combined using the principle of superposition. It is endorsed by major design codes such as BS8110 [1], EC2 [2] and ACI 318 [3]. The assumption of linear elastic behaviour is reasonable at low levels of loading but it becomes increasingly invalid at higher loads due to cracking and the development of plastic deformations. Once an element cracks the behaviour becomes non-linear but it is still reasonable to assume that the tension reinforcement and the concrete in compression both behave elastically up to yield of the reinforcement.