巨型钢管混凝土分叉柱节点压弯性能试验研究

为了解决构造措施对巨型钢管混凝土分叉柱节点承载力影响程度的问题,以在建工程北京"中国尊"为工程背景,进行了2个不同构造的分叉柱节点偏心受压重复荷载试验,研究了其受压破坏特征、承载力、侧向抗弯刚度、侧向变形及应变规律.结果表明:试件的破坏形态以弯曲破坏为主,破坏位置与分叉柱节点刚度分布有关,且侧向变形主要发生在侧向位移较大的柱肢部分;在钢管屈服之前,柱肢异形截面符合平截面假定,钢材屈服以后基本符合平截面假定;在忽略横向构造措施承载力贡献的情况下,仅考虑钢管的约束效应计算承载力与实测值相差较大,说明受压区钢管及横隔板的组合约束效应更强.

Experimental Study on the Bifurcated Columns Joint of Mega-CFST Under Eccentric Load

To solve the influences of constructions of bifurcated joint of mega concrete filled steel tubular columns( CFST) , based on China Zun Tower, two specimens with different constructions under eccentric repeated load were conducted. The authors studied the failure modes, ultimate strength, flexural rigidity, deflection, and strain law. The results show that the bending damage is the main failure modes and is associated with the stiffness distribution and value of legs of bifurcated columns joint. Before the steel yield, the longitudinal strains of the leg perfectly accord with plane cross-section assumption, approximately according to it after the steel yield. Without considering the bearing capacity of diaphragms, it is non-ignorable for the difference of the tested value and calculated value coupling with confined effect of steel, which states the stronger composite confined effect between multi-cell steel tube and diaphragms at compressive zone.