内置工字形CFRP型材的方钢管混凝土中长柱双向偏压性能研究

Performance Study on the Mechanical Behavior of a Concrete-Filled Square Steel Tubular Middle-Long Columns with Inner I-shaped CFRP Profiles Under Bi-axial Eccentric Loading

为了深入了解内置工字形CFRP型材的方钢管混凝土中长柱的力学性能,通过试验与有限元分析结合的方式研究了其在双向偏心状态下的工作机理及破坏形态。在此基础上,对典型构件进行了全过程分析,研究了偏心率、含钢率、长细比、钢材屈服强度以及混凝土抗压强度对构件受力性能的影响。研究结果表明,内置工字形CFRP型材的方钢管混凝土中长柱的荷载-挠度曲线可分为弹性阶段、弹塑性阶段、塑性强化阶段以及下降阶段4个阶段;CFRP型材与钢材及混凝土有着良好的协同工作性能,可加强对混凝土的约束作用,CFRP型材最终发生脆性破坏;构件的极限承载力随着长细比及偏心距的增加而降低,随着含钢率、钢材屈服强度及混凝土强度的增加而提高;构件的初始刚度随着长细比及偏心距的增加而降低。

In order to study the mechanical behavior and failure mode of concrete-filled square steel tubular(CFSST)middle-long columns with inner I-shaped CFRP profiles under bi-axial eccentric loading,experimental study and finite element analysis are carried out.On this basis,the whole process analysis of typical components is carried out.The effects of eccentricity,steel ratio,slenderness ratio,steel yield strength and concrete compressive strength on the mechanical properties of components are studied.Results show that the load-deflection curves of the CFSST middle-long columns with inner I-shaped CFRP profiles under bi-axial eccentric loading can be divided into four stages:elastic stage,elastic-plastic stage,plastic strengthening stage and descending stage.The CFRP profiles,steel,and concrete have good working performance,and the restraining effect on concrete can be strengthened.Finally,brittle failure occurs in the CFRP profiles.The ultimate bearing capacity of the components reduces with the increase of slenderness ratio and eccentricity,and increases with the increase of steel ratio,steel yield strength and concrete strength.The initial stiffness of the components decreases with the increase of slenderness ratio and eccentric distance.