组合式十字形钢管混凝土柱偏压力学性能试验研究

Experimental study on mechanical behavior of combined cruciform concrete filled steel tubular column under eccentric compression

设计了一种由槽钢和方形钢管拼焊形成的组合式十字形钢管混凝土柱,将其灵活地布置在框架结构的中节点,可使柱肢与填充墙等厚,有效地提高建筑使用面积。共制作了6根组合式十字形钢管混凝土柱试件,考虑了偏心距和长细比两种变化参数。通过对其进行偏心受压试验研究,考察了试件的破坏形态和荷载-挠度曲线,并分析了其在不同偏心距和长细比下的荷载-应变曲线发展规律。结果表明:组合式十字形钢管混凝土柱中钢管和槽钢对混凝土的约束作用强,表现为较高的延性系数;偏心距或长细比越大,试件的极限承载力及弹性刚度越小,且偏心距越大延性越好,长细比对延性影响不显著;在受拉侧纵向应变基本上符合平截面假定,在受压侧纵向应变不符合平截面假定。

One kind of combined cruciform concrete filled steel tubular columns made of channel steel and square steel tube is presented.The thickness of column leg can be equal to filler wall and the usable floor area of buildings can be effectively increased when the columns are arranged flexibly on the middle joint of frame structures.Six combined concrete filled steel tubular columns are designed and fabricated with the slenderness ratio and eccentricity as variable parameters.Through the eccentric compression,the failure pattern and load-deflection curve of the specimens are investigated,and the development laws of load-strain relationship corresponding to different eccentricity and slenderness ratio are analyzed.It is shown that the steel tube and channel steel in the combined cruciform concrete filled steel tubular column have strong constraint on the concrete and show better ductility.With the increase of eccentricity or slenderness ratio,the ultimate bearing capacity and elastic stiffness of the specimens decrease.The greater the eccentricity is,the better the ductility is,while the slenderness ratio has no significant effect on ductility.Moreover,the longitudinal strain on the tension side is basically in accordance with the plane cross-section assumption,while the longitudinal strain on the compression side is not in accordance with the plane cross-section assumption.