Behavior of Pre-Cracked Reinforced Concrete Beam Strengthened with Prestressed CFRP Plate

Abstract

The technique of strengthening structures with prestressing CFRP can improve the load-carrying behavior of reinforced concrete structures and has gained more and more attention recent years. However the research about behavior of the pre-cracked structures after retrofit is rather limited. In this paper two RC beams with large dimension were constructed. One beam was strengthened by non-prestressed CFRP plate serving as reference beam. And the other beam had been loaded to its yielding load before it was strengthened with a prestressed CFRP plate. The monotonic tests were conducted to investigate the effect of strengthening with prestressed CFRP on the behavior of the pre-damaged beam. Based on the experiment results, the comparison of behavior between the beam with non-prestressed CFRP plate and the pre-cracked beam with prestressed CFRP was conducted. The experiment results indicated that although having been loaded to its steel yielding before being strengthened, the specimen with prestressed CFRP plate had a load-carrying capacity no less than the intact beam with non-prestressed CFRP plate. Despite the serious damages of section, the stiffness of the pre-cracked specimen was almost equal to that of the reference specimen, which indicates that the technique of strengthening structures with prestressed CFRP plates can be effective in the retrofit of the seriously cracked reinforced concrete structures.