Research on the new bridge strengthening system with prestressed CFRP strips

The use of CFRP prestressed strips in strengthening work have gone through a big development during the past 10 years. The bending strength and stiffness of both concrete and steel beams can be considerably enhanced with this technique. The main problem of strengthening with prestressed strips has been the anchor zones. Without mechanical anchorages there have been peeling failures at the ends. Therefore the still development in CFRP strips anchorage systems has been recently observed. The paper briefly describes the research on the new prestressing system for CFRP strips with special steel anchorages. The initial testing revealed that the concept might be used for strengthening of reinforced concrete beams. The ultimate strength of steel anchorages is as high as 70% the ultimate tensile strength of CFRP strips. When system has been used on concrete beams, more than 50% strengthening efficiency has been obtained.