Flexural Behavior of RC Beams Strengthened with Near Surface Mounted Prestressed FRP

Strengthening concrete structures with FRP(fiber reinforced polymer) have grown to be a widely used method over most parts of the world today, which FRP was developed in 1960's. A method to apply prestressing force to FRP is developed newly in these days, which can use the maximum performance of FRP materials. This study investigated the flexural behavior of simply supported Reinforced Concrete(R/C) beams strengthened with Prestressed Near Surface Mounted (NSM) CFRP(carbon fiber reinforced polymer) . CFRP plate and rod were used for flexural strengthening. Prestressing level changed from 0 % of CFRP tensile strength to 50 %. Any mechanical device has not been used to maintain the prestress during testing. Static four point loading tests are conducted for eleven R/C beams strengthened with Prestressed Near Surface Mounted (NSM) CFRP and Non-prestressed Near Surface Mounted (NSM) CFRP. The test shows that the beams with prestressed NSM CFRP exhibited a higher yielding load and a higher ultimate load, compared to the beams with non-prestressed NSM CFRP and the control beams. Beams strengthened by CFRP rod failed due to fiber rupture of the FRP in the groove, but beams strengthened by CFRP plate failed due to concrete cover separation.