Simulation Analysis On The Fatigue Performance Of The Concrete Beams Strengthened With Multi-points Anchoring Prestressed CFRP

On the base of wave-shaped-gear-grip(WSGG)anchor, multi-point anchoringprestressed CFRP strengthening technology is a kind of unbonded reinforcementtechnique in vitro. Using this technique can reliably achieve the anchorage and stretchof CFRP in a convenient and speedy way. Through abundant previous static loadexperiment and theoretical research, the obvious effects and reliable performance of thistechnique haven been proved. Nevertheless, investigation about fatigue property ofmulti-point anchoring prestressed CFRP strengthening technology just gets off theground. Because of the long period and huge expense of fatigue test, conductingabundant fatigue test is restricted. So, model analysis turns into a significant method.Based on fatigue tests of two strengthening beams, finite element simulationanalysis of these multi-point anchoring prestressed CFRP strengthening beams has beenmade. The main content and conclusion of investigation are as follow.①Choosing various kind of element and constitutive relation which correspond toactual materials, Finite element model of these beams was established by using ANSYSsoftware. Cracking load, mid-span deflection, height change of neutral axis, stress ofrebar, stress of CFRP and strain of concrete were analyzed under dead load. Accuracyand reliability of mode was verified by comparing calculated results with experimentalresults.②Based on statical analysis, nominal stress method was applied. Fatigue life ofstrengthening beams was estimated by using ANSYS software. In contrast toexperimental results, the error was very tiny. So the reliability of simulation analysismethod of fatigue property of multi-point anchoring prestressed CFRP strengtheningbeams was verified.③Considering the influence of CFRP amount, anchor numbers and interval,prestress of CFRP, a series of simulation analysis of multi-point anchoring prestressedCFRP strengthening beams were developed by using verified simulation analysismethod and obtained the following conclusion.1.Increasing the amount of reinforcementcan improve ultimate bearing capacity and fatigue life of component drastically.2.Thelocation and interval of anchorage point have an effect on the location of dangerouspoint of main reinforcement under fatigue load.3.As far as this study is concerned,prestress can improve ultimate bearing capacity of component. For three anchor beam, the bigger the prestress is, the longer fatigue life is.For four anchor beam, in midpiece,the bigger the prestress is, the shorter fatigue life is, while in sidepiece, the bigger theprestress is, the longer fatigue life is.But the changing extents of both locations wereequally tiny.