Experimental Evaluation of PSC Structures from FRP with a Prestressing Strengthening Method.

A prestressed concrete (PSC) structure is subject to prestress losses in the long and short terms, and the structure ages over time. The structure is susceptible to corrosion from exposure to environmental factors such as moisture, chloride, and carbonation, thus causing prestress loss. Therefore, strengthening the structure is needed to address this problem. Here, the near surface mounted (NSM) method and the external prestressing (EP) method were selected because they are capable of applying additional prestressing. Further, we used fiber-reinforced plastics or polymers, or carbon fiber-reinforced plastics or polymers because of their high tensile strength and noncorrosive properties. For EP tests, prestressed strands were used. Accordingly, this study performs four-point flexural tests and evaluations for 12 types of specimens fabricated with different PSC methods. All specimens fabricated with the NSM (prestressing, no prestressing) and EP methods achieved stiffness that was 50-60% higher than that of the control PSC specimen. It was observed that the EP method in conjunction with prestressing yielded the best strengthening effect. It is expected that the results of this study will be applied to real structures for strengthening them and improving their performances.