Stress Simulation Analysis And Optimization On Wedge-Type Clamp Anchor Of Prestressed Carbon Fiber Reinforced Plastic Plate

Strengthening and repairing damaged bridges can not only improve the working performance of bridges,but also save costs.Prestressed CFRP plate reinforcement is an advanced active reinforcement technology,and the reliability of prestressed CFRP plate reinforcement system is determined by safe,convenient,efficient and stable anchorage.In this paper,the wedge-shaped clamp anchorage in prestressed CFRP plate reinforcement technology is studied in detail based on the application background of prestressed CFRP plate reinforcement project of an expressway bridge.The following research are the main contents of this paper:(1)The anchoring principle of wedge-shaped clamp anchorage with CFRP plate is analyzed.The stress of wedge-shaped clamp anchorage is mainly divided into three stages: pre-tightening assembly,pre-tightening unloading and carbon plate tension.The stress state of anchor plate,clamping plate and carbon plate is analyzed theoretically in three stages,and the reasonable anchorage size is designed on this basis.(2)Finite element models are established for wedge-shaped clip anchor with or without considering the colloidal action between clip and carbon plate.The results show that the stress concentration phenomenon is the most obvious at the change of inner wall section of tapered hole of anchor plate;The notch effect caused by the clip affects the tension safety of the carbon plate;The normal stress of the anchor plate on the clip and the friction between the clip and the carbon plate have great influence on the anchoring effect of the anchor;Carbon plate adhesive can reduce the vertical shear stress of clip to carbon plate by 24.9%.(3)By comparing the finite element calculation with the theoretical calculation,it is known that the normal pressure value of anchor plate is 10.7% larger in numerical simulation.The theoretical formula of normal pressure of anchor plate is modified,and the amplification factor is added,which is 1.2.(4)The finite element method is used to simulate the influence of anchor plate taper hole form,anchor plate length and anchor plate chamfer size on anchorage stress.The new anchor plate taper hole form can greatly reduce anchor plate stress concentration and carbon plate shear stress,and the maximum equivalent stress can be reduced by 45.8%.The longer the length of anchor plate,the smaller the Von Mises equivalent stress of anchor plate and the anchor plate length is 200 mm by comprehensive comparison.The chamfer setting of anchor plate obviously weakens the stress concentration phenomenon on the inner wall of taper hole by 33%.After comprehensively comparing the anchors with three chamfer sizes,AO 、AO 、and AO,it can be concluded that the comprehensive performance of AO is the best.(5)Taking the construction monitoring of CFRP plate tension process in a bridge reinforcement project as an example,the construction steps of prestressed CFRP plate reinforcement are introduced.The monitoring test data show that the stress-strain response of the bridge during reinforcement is basically consistent with the design value.the anchorage efficiency is high,the loss of prestress and the slip of carbon plate are less.Through the above research in this paper,it can provide reference for anchorage design of prestressed CFRP plate reinforcement.