Analytic Research On Concrete Box Column Seismic Performance Based On The Shear Lag Effect

In order to study the change of shear lag effect of box section column and its influence on seismic behavior of concrete box section column,In this paper,the low cycle repeated loading tests and theoretical analysis of three scale members are carried out,and the influence of wall thickness ratio and reinforcement ratio on the shear lag effect of reinforced concrete box section columns is studied.By comparing the theoretical values of shear lag effect with the experimental results,the influence of shear lag effect on the seismic performance of concrete box columns is analyzed.Finally,ABAQUS software is used to do the relevant simulation analysis,in order to verify the influence of wall thickness ratio and reinforcement ratio on the shear lag effect of box section columns,and after considering the shear lag effect,Relationship between seismic behavior of concrete columns and experimental results and theoretical values.Through the analysis and research,the main results are as follows:(1)from the point of view of the shear lag effect of concrete box section columns,the change of web wall thickness ratio is relatively weaker than that of flange wall thickness ratio.with the increase of wall thickness ratio,the box section columns are less affected by shear lag effect.After entering the nonlinear stage,the shear lag coefficient λ of the member will become more significant when the wall thickness changes.(2)from the point of view of the influence on the shear lag effect of concrete box section columns,with the increase of reinforcement ratio,the box section columns are less affected by shear lag effect.At the same time,the shear lag value of concrete changes obviously from before cracking to plastic stage,and after cracking,the shear lag coefficient of its section is significantly affected by the change of reinforcement ratio.(3)considering the shear lag effect,the experimental values are close to the theoretical values,and the two overlap with the increase of loading;However,there is a big difference between the experimental value and the theoretical calculation value without considering the shear lag effect,and the fluctuation range between the two is about 5%.(4)the smaller the shear lag effect is,the fuller the hysteretic curve is,the greater the ultimate bearing capacity is;the larger the yield displacement is,the stronger the structural resistance is;at the same time,the stiffness fading curve tends to be flat;ductility will also have a better performance.(5)through ABAQUS software,the simulation results verify that the shear lag effect characteristics obtained by experiment and theoretical analysis with the change of wall thickness ratio and reinforcement ratio are unified and correct.Considering the shear lag effect,the seismic resistance of concrete box columns tends to be synchronized with the results of experimental and theoretical analysis.In this paper,through quasi-static test research,combined with finite element simulation and related theoretical analysis,the shear lag characteristics of box section column and the influence of shear lag effect on seismic performance of concrete are obtained.It has great reference value for the follow-up study and the application of practical engineering.