Effectiveness of Shear and Flexural Repair and Strengthening of Box-section Steel Beams using CFRP Laminates

Steel structures are generally subjected to damages and defects due to different causes such as corrosion, fracture cracking, fire, buckling…etc. Damaged or defected parts may include girders, columns, welds, splices, base plates…etc. There is a wide range of techniques used for repair and strengthening starting with using protective coatings and ending up with full replacement of the damaged parts. Fiber Reinforced Plastic (FRP) laminates are widely used now in the field of repair and strengthening of different types of structures (reinforced concrete structures, steel structures, masonry structures, timber structures….etc.). The main goal of this research is to investigate the effectiveness of using Carbon Fiber Reinforced Plastic (CFRP) laminates in repair and strengthening of steel beams (in both flexural and shear). A total of five box-section steel beams were tested in three point load flexure test to determine the stiffness and ultimate load carrying capacity of the strengthened and repaired beams using CFRP laminates and compare the obtained results for these beams with those of the fifth beam which used as a control beam (without CFRP laminates). Test results showed that the effectiveness of using CFRP laminates for repair and strengthening of steel beams depends mainly on the obtained modes of failure. Highest effectiveness was obtained in tension failure modes while almost no effectiveness obtained in compression failure modes.