Flexural Strengthening of Reinforced Concrete Beams with Steel-reinforced Polymer Composites: Analytical and Computational Investigations

This article presents analytical and computational models for reinforced concrete beams strengthened in flexure using an emerging composite material, steel-reinforced polymer (SRP). The SRP composite consists of unidirectional high-carbon steel fabric embedded in a polymeric resin, providing high strength and stiffness at a reasonable cost. The models developed and examined include finite element analysis, strain compatibility analysis, and closed-form equations reported in the literature and design codes. The study focuses on the load-deflection and load-strain responses, strain variation along the SRP sheets, shear stress distributions and concentrations near the cut-off points of SRP sheets, and cracking behavior. In general, the study shows that flexural strength and deflection at service loads can be well predicted using the models. The shear stress concentration near the cut-off points of SRP sheets may be approximated to 10% of the resin tensile strength just prior to SRP delamination. Confining effects by the adequate end-anchorage effectively redistribute the applied stress in the strengthened beam.