Wang Zhen, Liu Zhe, Zhou Xuejun
School of Civil Engineering, Shandong Jianzhu University, Jinan 250101, China.
Shandong Winbond Construction Group Co., Ltd., Weifang 262500, China.
Materials (Basel). 2022 Jun 13;15(12):4179. doi: 10.3390/ma15124179.
Special-shaped concrete-filled steel tube (SS-CFST) columns can be embedded in the wall, thus preventing the columns from protruding. This feature makes it popular in steel residential buildings. This paper proposes a new special-shaped concrete-filled square steel tube (SS-CFSST) composite column composed of multiple square steel tubes connected by steel hoops to form L-, T- or cross-shaped sections. Eight specimens were tested under axial loads with section shape, construction method, slenderness ratio, steel tube thickness, and steel strength as variation parameters. The structural performance, such as failure modes, peak load, load-displacement curves, load-strain curves, and Poisson's ratio of the steel tubes, were analyzed. The tests illustrated that the failure modes of hoop-type specimens and weld-type stub columns were mainly the local buckling of steel tubes and bending failure, and those of the weld-type slender columns were mainly overall bending failure. The load-carrying capacity of the hoop-type specimen was higher than that of the weld-type specimen with the same cross-sectional dimensions and slenderness ratio. Next, the stress-strain relationship model of core concrete in the SS-CFSST composite column was established by considering the restraint effect of the connection coincidence area of steel tubes and steel hoops on concrete. Additionally, the finite element model (FEM) of the column was established using this constitutive model. By comparing the failure modes, load-strain curves and bearing capacities obtained from the tests and FEM, the established FEM can accurately evaluate the mechanical properties of SS-CFSST composite columns with steel hoops under axial compression.
异型钢管混凝土（SS-CFST）柱可以埋入墙体，从而避免柱体突出。这一特性使其在钢结构住宅建筑中颇受欢迎。本文提出了一种新型异型方钢管混凝土（SS-CFSST）组合柱，它由多个通过钢箍连接的方钢管组成，形成L形、T形或十字形截面。以截面形状、施工方法、长细比、钢管壁厚和钢材强度为变化参数，对8个试件进行了轴向加载试验。分析了试件的破坏模式、峰值荷载、荷载-位移曲线、荷载-应变曲线以及钢管的泊松比等结构性能。试验表明，箍筋式试件和焊接式短柱的破坏模式主要是钢管局部屈曲和弯曲破坏，焊接式细长柱的破坏模式主要是整体弯曲破坏。在相同截面尺寸和长细比的情况下，箍筋式试件的承载能力高于焊接式试件。接下来，考虑钢管与钢箍连接重合区域对混凝土的约束作用，建立了SS-CFSST组合柱核心混凝土的应力-应变关系模型。此外，利用该本构模型建立了柱的有限元模型（FEM）。通过比较试验和有限元模型得到的破坏模式、荷载-应变曲线和承载力，所建立的有限元模型能够准确评估带钢箍的SS-CFSST组合柱在轴向受压下的力学性能。
