Retrofitting of Existing Rc Square Bridge Columns Using Basalt Frp Rebars

Fiber-reinforced polymers (FRPs) have been widely utilized to improve the seismic performance of deficient reinforced concrete (RC) columns. In recent years, one of the emerging types of FRPs used is basalt fibers. In this study, the performance of existing columns was experimentally examined before and after applying near-surface mounted (NSM) basalt FRP (BFRP) rebars as a retrofitting technique. Three specimens, representing a deficient square RC bridge column with poor transverse reinforcement detailing, were tested under cyclic displacement excursions and constant axial load. Since bond is the means for the transfer of stress between the concrete and the FRP reinforcement to develop the composite action, one column was retrofitted with smooth NSM BFRP rebars and another with deformed NSM BFRP rebars. The preliminary test results showed that using smooth BFRP rebars could lead the strengthened column to achieve the highest lateral drift meanwhile the column can still carry load after the steel reinforcement yields. On the other hand, the favorable mitigation of the column permanent deformation could be when rebars with rough texture are used.