Replaceable CFRP-steel Composite Plates Reinforcement Technology For RC Beams

Structural reinforcement is one of the effective means to prolong the service life of the structure.At present,the traditional reinforcement methods mainly include the reinforcement of carbon fiber(CFRP)plates and the reinforcement of bonded steel plates.These methods have a good reinforcement effect in the short term,but it is difficult to do once and for all when dealing with the secondary risk that the reinforced bridges are once again subjected to continuous overloading and the deterioration of the reinforcement material itself.Replacement reinforcement technology is expected to provide new ideas for solving the overload fatigue reinforcement problem.Carbon fiber materials(CFRP)are widely used in the field of reinforcement because of their high specific strength and excellent fatigue resistance.The cost of steel plates is low,and the processing and installation technology is mature.Under the existing technology,CFRP plates cannot be replaced.To sum up the above reasons,the need to replace the steel plate to maximize the service life of the bridge.Based on the replaceable reinforcement method of RC beam structure fatigue damage caused by overload fatigue proposed by Zhou Zhi Group of Dalian University of Technology,this paper designs a CFRP plate-steel plate composite anchorage that can be used for replaceable steel plates,and a composite anchorage device.It is applied to the static load and fatigue test of reinforced beams,and the finite element simulation platform is used for the simulation analysis of the components to verify the reinforcement effect of composite reinforcement and the feasibility of CFRP plate-steel plate composite anchorage.The main contents are as follows:(1)Based on the CFRP board clamped anchorage developed by this research group,in order to meet the requirement of replaceable reinforcement,a CFRP-steel composite anchorage with replaceable steel plates was designed.Based on the anchoring mechanism of wedge-shaped clips and the shear resistance of bolts,the structural design of composite anchors was carried out.Through the combination of finite element simulation and theoretical calculation,reasonable anchorage dimensions were finally obtained.The installation process of composite anchorage was introduced and referenced for practical application.Finally,through the anchorage performance test,it is verified that the anchorage performance of the composite anchorage is reliable and the failure mode is reasonable.(2)The CFRP plate-steel plate composite anchorage was applied to the static and fatigue tests of concrete beams.The results showed that the mechanical properties of the beam structure such as static load failure,tensile strain,crack width,and beam deformation were changed with fatigue damage.The law and comprehensive analysis show that the composite anchorage has good application effect and fatigue resistance in reinforced concrete beams.Composite reinforcement can improve the bearing capacity of the beam and improve the stress performance of the beam.(3)The finite element simulation platform was used to simulate and verify the force of composite reinforced beams based on CFRP plate-steel composite anchors,and compared with the test results to verify the accuracy of the model.The prediction of the fatigue life of the composite reinforcement and the ordinary RC beam validates that the composite reinforcement form can promote the extension of the fatigue life of the beam.