Experimental Study On Shear Behavior Of Reinforced Concrete Beams Shear-strengthened With Anchored FRP U-strips

Fiber Reinforced Polymer (FRP), due to its advantages such as a heigh strength, low weight, and high corrosion resistance, has been widely applied in struactural strenghenening; and shear-strenghtening of reinfocec concrete (RC) beam using FRP U-strips is one of usch applications. Existing research has showed that anchors can be used to significantly enahcne the shear capacity of RC beam shear-strengthened with FRP U-strips and thus increase the efficency of FRP material in shear strengthening. Aming to remove the drawbacks of existing anchoring device, this study proposed a new anchoring devices which can be used to effectively enhance the shear strengthening of FRP U-strips; to investigate the influcences of the proposed anchoring devices on the shear strengthening effect of FRP U-strips, tests were then carried out to explore the shear behavior of T-section RC beams in both posigtive and negative moment zones. The main contents covered by this thesis are as follows.(1) Following the previous study of Li,on fiber anchors, experimental studies were carried out on T-section RC beams shear-strengthened with FRP U-stripsed anchored by different anchoring devices. A total of 5 beams were testsed, and the following three anchoring devices were investigated:fiber anchor Ⅱ, embedded anchor Ⅰ, and embedded anchor Ⅱ. The test results showed that embedded anchor Ⅱ enables both the self-anchoring between FRP strips and anchoring devices and the self-anchoring between anchofing devices and surrounding concrete; as a result, this anchoring device can be used to significantly enchance the shear capacity of RC beams shear-strengthened with FRP strips.(2) Following the expereimntal studies mentioned in stage (1), further experimental studies were carried out on RC beams shear-strenghtened in negative moment zone with FRP U-strips anchored with embedded anchor Ⅱ. In this stage, a total of 6 beams were tested which can be grouped into two series:beams with steel stirrups and beams without steel stirrups. Each series included three beams:one RC beam (without strengthening) control beam, one beam strengthened with only FRP U-strips(for comparision), and the third beam with anchored FRP U-strips. To similate the loading condition in negative moment zone, all the sixe beams were tested as inverted T-section RC beams (with the flange of the beam in tension side). The results showed that the embedded anchor Ⅱ can also be used to effectiveluu inease the shear capacity of RC beams shear strengthened in negative moment zone with FRP strips.