Ultimate strength prediction for RC beams externally strengthened by composite materials

Abstract

A simple and efficient computational analysis to predict the nominal moment capacity of RC beams strengthened with external FRP laminates is presented. It considers the determination of the limits on the laminate thickness in order to assure tensile failure due to steel yielding and to avoid tensile failure due to FRP laminate rupture. The study presents the design of laminate thickness to attain a specified moment capacity in a given beam. Furthermore, the study affords the approach to determine the laminate thickness of any type of composite material available that is equivalent to FRP laminate required to achieve the desired moment capacity. This approach helps in studying comparative costs of rehabilitation using different FRP materials. The analytical and experimental results of series of beams strengthened with different number of layers of glass/epoxy or carbon/epoxy FRP laminates are presented. The results show that the design guidelines presented in this study performed well in prediction of experimental results.