Research On The Mechanical Properties Of Reinforced Concrete Beams Reinforced With CFRP

CFRP is widely applied in civil engineering.It has many advantages,such as high strength,corrosion resistance and light weight.It is widely used in reinforcement of building structures.CFRP has many advantages,and the cost is cheap,people begin to carry out extensive tests on CFRP,obtained a lot of theoretical knowledge,found a lot of CFRP law,and gradually applied to the actual structure of the CFRP reinforcement,the reinforcement technology development.However,because of the shortcomings such as large uncertainty,high cost and long consumption period,numerical analysis can make up for these shortcomings.Combining experiment with numerical simulation can better study its regularity.Before writing this paper,the author collected a large amount of CFRP references,and a detailed reading of the literature on the research of the mechanism and results of CFRP are summarized in detail,his profound knowledge and understanding of the CFRP,and then the ANSYS finite element analysis software system of careful study,on this basis,through the establishment of model set an example,finite element analysis of CFRP reinforced beams under stress,the main work is as follows:1.This paper introduces the current situation of the domestic buildings,introduces the commonly used reinforcement methods,lists the advantages of the CFRP and the research status of the CFRP at home and abroad.2.First of all,the principle of CFRP reinforcement is carefully studied and understood,and the previous theories and methods are summarized.Combined with related mechanics knowledge and referring to the research done by others,the formula of normal section bearing capacity of CFRP strengthened beam under bending condition is introduced and deduced.3.First,the analysis function and general analysis steps of finite element software are introduced.Three basic analysis models of concrete are introduced.The methods of solving nonlinear problems,the convergence criteria of the solution methods,and the type of cell selected by finite element models are introduced.In this model,four kinds of materials involved,therefore there are four types of unit of these materials were simulated,respectively: the concrete selection of SOLID65 element,LINK8 element selection of reinforced CFRP,selection of SHELL41 element,elastic cushion,selectionof SOLID45 element,and these elements are introduced.And then,in the process of establishing the model,the processing,solving,and the matters needing attention in the post processing stage are introduced in detail.4.First,a large number of documents are read,and the experimental data of the related CFRP reinforcement are collected,and a set of experimental data is selected to study.According to the test data,the finite element analysis model is established,by comparing the experimental data and finite element calculation,the yield load,ultimate load difference is very small,the error is within the allowable range,the test may well prove the model is reasonable,and thus lay the foundation for the next research.5.The basic work in the fourth chapter,on the carbon fiber reinforced beams were studied,the design of finite element calculation example,designed a total of five groups,considering the five factors,then the paper study the five factors,the conclusion is: the first factor first consideration is the reinforcement ratio,with the increase of reinforcement beams,the ultimate load of the beam and the yield load is larger,but as the reinforcement ratio increases,the data obtained show that the beam bearing capacity increases more and more small,reaches a certain limit,the reinforcement ratio on the bearing capacity of the beams increase force without any effect;the second factors considered for the concrete strength,when the beginning of concrete strength is relatively low,the concrete is fully utilized,with the increase of load,concrete crush damage,but at this time CFRP does not give full play to the reinforcement effect,its efficiency is relatively low,with the increase of concrete level,the CFRP play a reinforcing effect,is fully utilized,with the increase of load,the final failure mode of beam for CFRP tensile failure,the data indicate that the strength of concrete has little influence on the characteristics of load lifting beam;third factor is the amount of CFRP,with the increase of CFRP content,beam yield load and ultimate load are improved greatly,deflection control,beam anti cracking ability is enhanced,but with the increase of the amount of reinforcement effect will be reduced,so in the actual reinforcement to determine a reasonable structure,CFRP,the most appropriate amount;fourth factors to consider for the loading degree of CFRP,beam and load characteristics And the relationship between stressed CFRP is not simply a linear growth relationship,start with the increase of CFRP stressed beam,yield load and ultimate load are increased,the deflection of the beam has also been reduced accordingly,but with the continuous increase of the stress,the growth rate of nearly flat,eventually almost no increase,at the same time the beam yield loadand ultimate load of impact is not the same,increase general stressed beam,mainly affects the yield load;bearing size to fifth factors considered by beam,beam with holding size increased,characteristic load decreases with the load,and the size of this continued to improve.To reduce the effect will be more obvious,so in the bridge building structure reinforcement before,should first the maximum possible to unload the structure,so as to charge use CFRP to reinforce the effect.6.Finally,according to the actual case of a strengthened beam during the internship,after the engineering case is simplified,and then the finite element model is established to study the stress,performance separately before reinforcement and after reinforcement beam,the study suggests that the damaged bridge in CFRP,the bearing capacity of the beams greatly the ability to improve further,effectively inhibit the cracks,the damaged bridge can continue to meet the requirements of.Through the introduction and analysis of the actual cases I have gone through,I can deepen the understanding of the application of CFRP in the actual structure reinforcement,and provide some references for the actual works of the reinforced beams.