Research On The Effect Of Cyclic Overload On The Flexural Performance Of RC Beams Reinforced With Prestressed CFRP

Carbon fiber reinforced polymer(CFRP)is a widely used as building materials for bridge reinforcement in recent years.CFRP plate has advantages of strong tensile property,corrosion resistance,good performance,and the small density.However,there are some backdraws in the research of the prestressed CFRP reinforcement for RC beam,such as incomplete load spectrum,less considering of overloading,the lack of fatigue life prediction method.Therefore,the effect of overload on the flexural and fatigue properties of RC beams reinforced by prestressed CFRP was studied in our research.The main research contents of this paper are listed as below:(1)Bending resistance of RC beam before and after prestressed CFRP reinforcement was analyzed by static load tests.The results show that prestressed CFRP sheets and longitudinal reinforced bars were under stress together to inhibit the development of cracks in the lower edge of RC beam and improves the overall rigidity and bearing capacity.(2)Finite overloading test was carried out on RC beam reinforced with prestressed CFRP.The influence of finite overloading on the flexural performance of RC beam was analyzed.The results show that the damage accumulation of RC beams increases with the increase time of overload loads.At the same time,the,the the damage of RC beams accumulated faster under greater overload loads.RC beams reinforced with prestressed CFRP can also produce residual deformation under overload.the size of residual deformation is related to overloading amplitude and overloading times.The growth rule of damage accumulation is obvious at the early stage and steady at the later stage.(3)According to the measured data overload transformer overload strengthening RC beams with prestressed CFRP cloth cycle load test,analysis of transformer overload cycle to influence fatigue life of prestressed CFRP reinforced RC beam.At the initial stage of amplitude overloading,the cracks of RC beams appear later and develop slowly.With the increase of The Times of amplitude overloading,the development speed of RC beam cracks strengthened by prestressed CFRP cloth is accelerated.Amplitude overloading mainly affects the position outside the end of prestressed CFRP cloth.The residual strain of reinforcement under longitudinal stress increases with the increase of The Times of amplitude overloading,and the increase rate slows down with the increase of The Times of amplitude overloading.The increase of the amount of prestressed CFRP can reduce the residual strain of reinforcement under longitudinal stress.