Abstract: FRP reinforced concrete members have many advantages, such as high bearing capacity, good durability and so on. At present, the bending performance of FRP reinforced concrete members is relatively more. However, in practical engineering applications, the components often work under repeated loads. In order to study the flexural performance of the FRP reinforced concrete members under fatigue load, the bending performance of the reinforced concrete members is studied. In this paper, the crack width of FRP reinforced concrete member under the action of fatigue load is studied. Based on the calculation theory of crack width of FRP reinforced concrete members under static load, the calculation formula of FRP reinforced concrete member under fatigue load is obtained by introducing the relevant parameters, and the modified formula is tested. The study shows that the fatigue damage of the FRP reinforced concrete member under the continuous load of fatigue load will result in the fatigue damage in the member, and the bond performance between the FRP reinforcement and the concrete, which makes the overall stiffness of the component lower, the early initiation of fatigue crack, and the increasing of the load cycle and the number of action times. The crack width will gradually increase, and eventually tend to a stable range of change. By introducing the parameter a of the bond slip of the FRP bar and concrete and the strain increasing coefficient of the concrete in the compression zone, the calculation method of crack width of FRP reinforced concrete members under fatigue loading is obtained.

Key words: FRP reinforced concrete member, fatigue load, crack width, calculation method