内置工字形CFRP型材的方钢管混凝土轴压长柱受力性能研究

Experimental research on concrete-filled square steel tubular slender columns with inner I-shaped CFRP under axial compression

对7个内置工字形CFRP型材的方钢管混凝土长柱进行了轴压性能试验研究,得到了荷载-跨中挠度曲线和荷载-应变曲线,并分析了其受力过程及破坏特征。试验结果表明:内置工字形CFRP型材的方钢管混凝土轴压长柱的破坏模式为弯曲失稳破坏。随着长细比的增大,试件的承载力降低。试件的荷载-挠度曲线可分为弹性段、弹塑性段以及下降段。采用ABAQUS有限元分析软件对内置工字形CFRP型材的方钢管混凝土轴压长柱受力性能进行有限元模拟,模拟结果与试验结果吻合良好。在此基础上,分析了长细比、混凝土强度、钢材强度、含钢率和有无CFRP对组合柱受力性能的影响。分析结果表明,长细比对柱的受力性能影响较大,随着长细比的增加柱的承载力明显下降;提高混凝土强度可以提高柱的承载力,但延性有所降低;提高钢材强度和增大含钢率均可以提高柱的承载力;设置工字形CFRP型材可以提高柱的承载力和变形能力。

Seven concrete-filled square steel tubular slender( CFST) columns with inner I-shaped CFRP have been tested under axial compression. Load-strain curves and load-mid-span deflection curves were obtained. The failure mode and the loading process were analyzed. The experimental results show that the failure mode of slender CFST columns with inner I-shaped CFRP is bending instability failure. The bearing capacity of specimens is decreased with the increase of slenderness ratio. The load-deflection curve can be divided into three stages of elastic stage,elastoplastic stage and decline stage. The finite element simulation of slender CFST columns with inner I-shaped CFRP under axial compression was carried out by using software ABAQUS. The simulation results were in good agreement with the experimental results. On this basis,the effects of slenderness ratio,concrete strength,steel strength,steel ratio and inner I-shaped CFRP on mechanical behavior were analyzed. The results show that the slenderness ratio has obvious effect on the mechanical behavior. With the increase of slenderness ratio,the bearing capacity decreases quickly. With the increase of concrete strength,the bearing capacity increases,but the ductility reduces. With the increase of steel strength and steel ratio,the bearing capacity increases. It can be found that the presence of I-shaped CFRP could increase the bearing capacity and ductility of columns.