Evaluation of externally bonded CFRP systems for the strengthening of RC slabs
The use of carbon fiber-reinforced polymer (CFRP) as externally bonded reinforcement (EBR) for the repair and strengthening of deficient structures have been taking place since the late 1980’s. Continuous efforts in material development and research activities, with strong links to engineering practice, give this application more and more interest worldwide. This paper presents an experimental study on flexural strengthening of reinforced concrete (RC) slabs with different CFRP systems, using different EBR techniques. All the slabs were tested to failure under simply supported conditions. CFRP EBR increased the flexural strength and reduced the deflections and crack widths of the strengthened slabs. Two modes of failure were observed, delamination and rupture of the CFRP reinforcement.
Strengthening of Reinforced Concrete Structures with Near Surface Mounted FRP Rods
Near Surface Mounted (NSM) FRP rods are now emerging as a promising technique, in addition to externally bonded FRP laminates, for increasing flexural and shear strength of RC members. The overall objective of this research project was to investigate the effectiveness of NSM FRP rods as a strengthening system for RC structures. First, bond characterization of NSM rods was carried out on coupon-size specimens, varying type of FRP rebars, bonded length and groove size. Then, the structural performance of full-size simply supported RC beams externally strengthened with NSM FRP rods was investigated. Glass and Carbon FRP rods of different sizes were used for flexural strengthening. Performance of the tested beams and modes of failure are presented in this paper. The test results confirm that NSM FRP rods can be used to significantly increase the flexural capacity of RC elements.
The analysis of reinforced concrete beams strengthened by epoxy bonded steel plates
Abstract An analytical method for the elastic analysis of the interaction between a concrete beam and a steel plate bonded to it by epoxy adhesive is presented. The shear and the peeling distributed forces induced into the epoxy are formulated. It is observed that large shear and peeling distributed forces are induced into the epoxy at a samll region at the edges of the steel plate. The cases where large tensile distributed peeling force is induced, are discussed.