Moment redistribution in RC beams retrofitted by longitudinal plating

Abstract

The ability to redistribute moment within a reinforced concrete frame or structure is an intrinsic requirement in design. This is generally dealt with using the established neutral axis depth factor, the ku approach, with fixed hinge lengths, which require the flexural member to fail by concrete crushing and which, in turn, requires large strains in the tension reinforcement. As longitudinally plated flexural members tend to fail by plate debonding or plate fracture before the concrete crushes, an alternative approach is presented which is based on variable hinge lengths, which can cope with beam failure at any tension reinforcement strain, and which can be applied to both longitudinally plated and unplated structures.