FRP rebar used as a reinforcement cage material, is a rod material made of longitudinally continuous glass fiber and a thermosetting polymer resin through a pultrusion process and surface treatment. The polymer surface is spirally wound by glass fiber bundles and wrapped with resin to form steel-like teeth to improve the bonding performance with concrete. Compared with ordinary steel bars, it has light weight, high tensile strength, high static shearing force but low dynamic shearing force, strong corrosion resistance, low elastic modulus, and cannot be processed on site (such as welding , bending) and other characteristics.
The connection of main rebar under force should be connected by a steel U-shaped card, and the U-shaped card should fit the diameter of the bar. The number of U-shaped cards at the connecting end of each bar shall not be less than two. Other positions connection between GFRP rebar and steel rebar, GFRP rebar and GFRP rebar can be tied with iron wire or nylon rope firmly.
Since the elastic modulus of FRP rebar is only about 21% of that of steel rebas, the rigidity of the reinforcement cage will be quite different from that of regular steel rebar reinforcement cages. If necessary measures to increase the rigidity of the rebar cages not taken in manufacturing, it will cause the problem of excessive deformation during the hoisting process of the rebar cage, which is a certain hidden safety hazard. Therefore, construction unit should pay attention to it.
Precautions for the construction of FRP rebar:
- Please wear gloves when cutting FRP rebarsto prevent fibers from penetrating the skin;
- Since the weightof FRP bars is only 25% of the steel bars, when casting concrete structures, FRP rebars may be suspended on the concrete due to the effect of vibrating, so iron wires or nylon ropes should be used to bind them firmly;