Study On The Performance Of CFRP Grids Confined Concrete

In recent years,Fiber reinforced polymer(FRP)confined concrete has conducted a large amount of experimental study and theoretical analysis at home and abroad,which achieved valuable study.FRP has many advantages,such as high tensile strength,high corrosion resistance,light weight and so on.FRP confined concrete can greatly improve the bearing capacity and ductility of plain concrete,which makes the concrete in three-dimensional compression.The previous studies mostly focus on the FRP materials(FRP sheet and FRP tube)which have unidirectional fiber,while the research about FRP grids,which have bidirectional equal-strength fibers,confined concrete is relatively poor.Compared with FRP sheet,FRP grid has a special superiority due to its unique characteristic in retrofitting.In order to study the axial performance and confinement mechanism of FRP grid confined concrete,this paper analyzed the mechanical performance of FRP confined concrete by experimental study,analytical study and FE modeling,mainly including the works as follows:(1)Experiment about axial compression performance of CFRP grid confined concrete columns.Test totally designed 30 specimens including three reference columns and others.Meanwhile,the parameters of test mainly consisted of kinds of factors,such as layer numbers,concrete strength,combination method and so on.The results showed that CFRP grid confined concrete could improve the bearing capacity and ductility of concrete columns.The CFRP grid confined concrete columns finally kept better integrity,which showed good ductility.(2)Assessment of the existing of FRP confined concrete stress-strain curves with hardening stage.According to the collected 170 experimental datas,new strength model and stress-strain model of axial compression bearing capacity of FRP grid confined concrete columns,which aimed at the various types of FRP,were proposed.The models were introduced into Lam and Teng formula to provide a more comprehensive stress-strain model,and the model results agreed well with the experimental results.(3)To sum up the rule that stress-strain relationship of FRP confined concrete with softening stage,propose the design model and the stress-strain model of CFRP grid confined concrete as well.Through comparing the model results and test datas,it can be found that the model results was in good agreement with the experimental results.So it provided a reference for the application of FRP confines concrete columns in engineering practice.(4)FE modeling about FRP grid confined concrete columns.By comparing the model results with the test results,it showed that the FE models were reasonable and the behaviors of the columns could be better predicted.Finally,using FE models to analyze the parameters which were not involved in the experiment,and the mechanical performance and the mechanism of constraint were analyzed in depth.