Analysis of Moment Redistribution in Fiber-Reinforced Polymer Plated RC Beams

Ductility of RC structures has always been a classical area of concrete research. Given the complexity of the problem, the great mass of research investigating ductility, and specifically, moment redistribution and rotational capacities, has used empirical approaches to quantify moment redistribution and invariably assumed that concrete crushing is the singular mode of failure. With the advent of new reinforcement materials such as fiber reinforced polymers, these empirical approaches are not necessarily appropriate as failure modes other than concrete crushing can occur. In this paper, the empirical approaches to moment redistribution are replaced by a structural mechanics approach that incorporates moment rotation directly into moment redistribution. A structural mechanics method for determining moment and rotation at failure for any RC section with any material properties is first presented and this is followed by a structural mechanics model for moment redistribution; these enable the moment redistribution capacities of any RC section to be quantified. Moment redistribution capacities of various sections are analyzed and it is shown that plated sections can have significant moment redistribution capacities much of which can be used in design.