Experimental Study On The Damage Mechanism Of Parallel Wire Cable Under Coupling Load And Electrochemical Corrosion

Cable stayed bridge has been trapped by many scholars at home and abroad due to its easy corrosion and difficult replacement.Therefore,corrosion damage and corrosion protection of cables has been a key research project of cable-stayed bridges.At present,a lot of research on cable corrosion of cable-stayed bridge has been carried out at home and abroad,but the simulation test of indoor accelerated corrosion is mainly the material corrosion test without stress state or single static stress,and the corrosion test under the condition of alternating stress is less.This paper,based on the National Natural Science Foundation Project "study on the corrosion fatigue damage mechanism and life prediction model of cable-stayed cable under the coupling action of alternating load and erosion environment"(No.51478071),analyses the mechanism of the alternating load on the electrochemical corrosion of the cable.The main research work and conclusion are as follows:Firstly,this paper summarizes the five main structure form of modern cable-stayed bridge cable: parallel steel rope,parallel(parallel)steel wire rope,parallel(parallel)steel wire rope,single strands of steel cable,enclosed cables.The main types of corrosion damage of cables in cable-stayed Bridges are cable sheath damage,anchor head damage and cable wire corrosion damage.Four forms of uniform corrosion,hole corrosion,stress corrosion,fatigue corrosion and corresponding damage mechanism of lasso wire are analyzed.Secondly,a study on accelerated test method for the coupling of static load,alternating load and electrochemical corrosion.Through reaction test bench and the anchor jacks to lasso static and cyclic loading,peak and val ey value,frequency alternating load through the bridge,the actual operation process simulation and reference for similar research is electrochemical corrosion imposed by homemade electrochemical corrosion test equipment,electrochemical corrosion test reaction and homemade equipment can also connect the counterforce test bench and the anchor jacks,load and coupling of electrochemical corrosion.Thirdly,the damage mechanism of cable steel wire under the coupling of load and electrochemical corrosion is analyzed.Study found that,electrochemical corrosion environment,the loss of weight of the cable wire increases with the increase of test cycle and accelerating,the stress imposed on cable wire,no stress corrosion rate has a promoting effect,and alternating stress promoting effect is greater than the static stress.It is also found that the change frequency of alternating stress has little effect on the degree of corrosion.Lastly,establish the corrosion cable steel wire and the whole lasso finite element model.The results show that the higher the uniform corrosion is,the worse the stress is.The simulation results of local corrosion show that the stress concentration in the pit is more serious with the increase of the pit radius.Corrosion of parallel wire cable can make internal wire cable stress value redistribution,make the outer wire stress increases,the inner layer steel wire stress decrease relatively,and alternating stress state,the section of the wire cable corrosion inside and outside layer stress value is larger than under static stress change degree,again alternating stress on the influence degree of cable corrosion is bigger than the static stress.