Research On Fatigue Performance Of Concrete Structure Reinforced By Prestressed TRM

Aiming at the problems of low strength utilization rate of fiber reinforced concrete structural materials and insufficient research on fatigue performance of fiber in high stress state.In this paper,through the static and fatigue test research on the four reinforced concrete beams reinforced with prestressed TRM,the mechanical mechanism of the reinforced beam under static load and the fatigue life under the action of fatigue load,strain and deflection of the steel bar and concrete,deflection and cracks are studied.And compare.Finally,the ABAQUS finite element software was used for numerical analysis and compared with the test results.Combining the above research,the following conclusions are obtained:(1)Under static loading,the cracking load,yield load and ultimate load of double-layer reinforcement are improved compared with single-layer reinforcement,and they are increased by 7.3%,6.3% and 12.4% respectively.(2)Under the same conditions,the mid-span deflection,concrete compressive strain,and tensile steel bar strain of the two-layer prestressed TRM test beam are relatively small compared to the test beam of the one-layer prestressed TRM,and the fiber mesh The increase in the amount of reinforcement can effectively improve the stress of the concrete beam and enhance its bending resistance.(3)Under fatigue load,the mid-span deflection,the mid-span concrete strain and the tensile steel bar strain increase continuously with the increase of the number of fatigue cycles.After a certain number of cycles,an inflection point occurs,and then a sudden change occurs.(4)Under the fatigue load,the crack development of the two-layer fiber reinforced concrete beam is slower than that of the one-layer reinforced concrete beam.It shows that the increase of the fiber mesh reinforcement can effectively improve the crack resistance of the concrete beam,and slow down the propagation and extension of cracks..(5)The fatigue life of the concrete beams strengthened by single-layer prestressed TRM is 239815 times and 258462 times respectively.The double-layer reinforcement is improved by 7.8% compared with the single-layer reinforcement,so the increase in the amount of prestressed TRM reinforcement can be better improved The fatigue performance of concrete beams improves the fatigue life of beams.(6)The deflection and strain changes of the reinforced beams obtained by numerical simulation are consistent with the curve changes obtained by the test.And under the same fatigue cycle times,the deflection value and steel bar strain value obtained by numerical simulation are smaller than those of the test.The fatigue life values obtained by numerical simulation are slightly higher than those obtained by the test,but within the controllable range of errors,which can be considered that the model is reliable.(7)By using nominal stress method to evaluate the fatigue life of two reinforced beams,the life of one-layer reinforced lower beam is 275,423 times,which is 15% higher than the test value under the same conditions;the life of two-layer reinforced lower beam is 304781,this is 18% higher than the test value under the same conditions.