At present, carbon fiber composite materials have been widely used in the field of bridge reinforcement and reinforcement. Especially for steel-concrete composite beam structures, carbon fiber composite reinforcement has achieved good results.

However, in the reinforcement of steel beams, if ordinary modulus carbon fiber is used, there will be a shear lag effect between the steel surface and the carbon fiber composite material, which is due to the large difference in elastic modulus between ordinary modulus carbon fiber and steel.

To this end, a high-modulus carbon fiber composite material has been developed to reinforce steel beam structural parts. The beneficial effects obtained through design, processing, and final testing, and the design criteria for strengthening and strengthening steel beam structures based on high-modulus carbon fiber composite materials are proposed.

Foreign countries have also conducted in-depth research on some basic scientific issues of CFRP-reinforced steel bridges. Effective methods are used to evaluate the effectiveness of various carbon fiber materials in strengthening and repairing different steel beam structures (such as overloaded beams, naturally degraded beams, undamped beams, and simulated corrosion damaged beams).

Previous studies have shown that a constant amount of carbon fiber reinforced composite materials can effectively improve the yield strength and ultimate bearing capacity of steel-concrete composite beams. However, in the steel beam structure, the modulus of elasticity of a constant amount of carbon fiber is still relatively low compared to steel, which tends to cause a shear lag effect between the steel surface and CFRP, so a large number of CFRP materials must be used to meet the elastic stiffness .

Application of HM-CFRP in steel beam reinforcement

In response, a four-year scientific research project was launched abroad to develop a high-modulus carbon fiber (HM-CFRP) system for the reinforcement and maintenance of steel bridges and steel structures.