Experimental Study Of Hybrid Bonding Of FRP To Reinforced Concrete Structures

Fiber Reinforced Polymer/Plastics (referred to as FRP) is a new type of civil engineering structural material. It is well-known because of its lightweight, high strength and excellent corrosion resistance. Currently, FRP is widely used in civil engineering for structure reinforcing in China. FRP strip reinforcement for structure of beams and slabs can significantly increase their flexural capacity and shear capacity, and limit the development of cracks effectively. However, there are some limitations in these three FRP reinforcement methods (EB-FRP, NSM-FRP, MF-FRP), which limit the use of FRP. To deal with these problems, Yu-Fei Wu synthesized the methods above and put forward a new reinforcement method called Hybrid Bonding of FRP (HB-FRP). This method can enhance the bond strength effectively. This paper bases on the HB-FRP method, and uses anchor bolts in lieu of mechanical fastener. Experiments are designed to verify the effectiveness of the improvement. The study details:(1) Stick CFRP to the surface of reinforced concrete beams. Then set reinforcement bolt on the beams. By comparing the workability of the beams reinforced only by CFRP with those by the HB-FRP method, inspect some improvements of beams reinforced by HB-FPR method on failure mode, limit load, ductility, crack evolution and other performance.(2) For the beams reinforced using HB-FRP method, change the piles of CFRP. Then proceed to the three-point bending test. Inspect the performance of piles of CFRP on the beams' failure mode, limit load, ductility, crack evolution, etc.The results showed that: the HB-FRP method combines the benefits of the EB-FRP method and the MF-FRP method. It prevented the breakdown of the bond of FRP strips, and also increased the effect of the MF-FRP method. With the piles of FRP strips increase, the limit load and ductility of reinforced concrete beams further enhanced. The HB-FRP method with three or four layers of FRP strips is more economic and reasonable method.Comparing the limit load of test value and theoretical value, it is found that the test value is slightly larger than the theoretical value, but an insignificant difference. So we can refer to this calculation method to calculate the limit load of the beam using HB-FRP method.