Shear and flexural strengthening of steel beams with thick carbon fiber reinforced polymer laminate

In this paper, shear and flexural behavior of structural steel beams strengthened by high modulus carbon fiber reinforced polymer (CFRP) laminates are presented. Totally, 18 steel specimens including 6 un-strengthened beams as control specimens and 12 strengthened steel beams with simple supports were tested under 3-point bending test set-up. All specimens were strengthened using the bonded system. Influence of different parameters including length of steel beams, section size of specimens, number of CFRP laminates, and location of CFRP laminates were studied. Based on anticipated failure modes, the bonded laminates were implemented on the surface of tension flange, compression flange, and web of beams. Three failure modes of flexural, shear, and lateral-torsional buckling failures were observed in the tested beams. The main goal of these experiments was to evaluate the enhancement in load capacity, beam ductility, and initial stiffness. The results showed that the yield load, ultimate load capacity, and energy absorption of strengthened steel beams improved up to 15, 29 and 28 percent, respectively. Finally, in order to predict test results and compare the actual and predicted valves, analytical and numerical studies were carried out.