Performance of steel beams strengthened with CFRP laminate – Part 1: Laboratory tests

Research on the behaviour of beams strengthened with different configurations of carbon-fibre-reinforced-polymer (CFRP) laminates, in both the serviceability and ultimate limit state, has been conducted at Chalmers University of Technology. Additionally, the failure modes and the interfacial shear stresses in the bond line have been studied. The methods used in the research work were laboratory tests and simplified analytical solutions and the work took the form of parametric studies on the strengthened steel beams. CFRP laminates and epoxies with different material properties were attached to the tension flange of steel beams with I cross-sections. The strengthened beams were tested in four-point bending where the deflection of the beams and the strains, in both the steel beams and the laminates, were measured. The results show that it is possible to increase the moment capacity of a steel beam with CFRP bonded to its tension flange. Additionally, it is possible to predict the degree of increase in capacity by using simplified analytical solutions.