Strengthen Steel Structures with CFRP
Carbon fiber has been used extensively not only for flexural strengthening of concrete structures but also for strengthening steel structures. It has been documented that bonding carbon fiber with fibers oriented along the length of a structure will increase flexural strength from 10 to 160 percent.
To repair a steel structure, the conventional technique is to externally weld steel plates. Steel plates showed their effectiveness in enhancing load-bearing capacity but they are cumbersome to install and prone to corrosion.
The carbon fiber method has become an attractive repair option due to its high strength, lightweight and resistance to corrosion. This method was mainly used in the aviation industry and the effects were found to be effective, so it was extended to repairing damaged steel structures in civil engineering. Research has shown that externally bonded carbon fiber can significantly increase the yield load of a rectangular Hollow Section Steel (HSS) beam; experimental results also indicate that carbon fiber can significantly reduce the post-damage deformation of repaired HSS.