横肋波纹板-方钢管约束混凝土短柱轴压力学性能

横肋波纹板-方钢管(CPST)约束混凝土柱是由横肋波纹板与四角钢管焊接而成,并在腔内浇注混凝土形成的横肋波纹板约束核心混凝土、方钢管与混凝土共同承担轴向荷载构件。为了研究横肋波纹板-方钢管约束混凝土短柱的轴压性能,开展了3根横肋波纹板-方钢管约束混凝土短柱轴心受压试验。由于横肋波纹板具有较高的侧向刚度,核心混凝土能够得到较好的约束,但波纹板基本不承担轴向荷载,试件最终的破坏形式依次为方钢管局部屈曲、横肋波纹板向外鼓曲、方钢管内混凝土及核心混凝土均被压碎。在此基础上,利用ABAQUS分析了6类关键参数:混凝土的强度、正方形钢管/横肋波纹板的壁厚和抗压强度、钢管的截面尺寸。研究结果表明:如果提高混凝土强度,则抗压承载力提高,而延性降低;方钢管的厚度增加对柱的承载力和延性均有提升;方钢管的强度变高,承载力也随之提高;如果增加横肋波纹板的厚度,则承载力、延性都提高;横肋波纹板强度的变化对承载力影响不大,对延性有所提升;随着方钢管外截面尺寸变大,承载力呈现出提高的趋势。最后,基于Mander等提出的约束混凝土抗压承载力计算公式,通过引入综合影响变量,提出了计算横肋波纹板-方钢管约束混凝土短柱抗压强度的公式,期望为工程实践提供指引。

Mechanical Properties of Horizontal Corrugated Plate-square Steel Tube Confined Concrete Stub Columns

A corrugated plate-square steel tube (CPST) confined concrete column is a corrugated plate confined concrete, steel tube, and concrete load-bearing member comprising corrugated plates and square steel tubes at four corners welded together. Three short CPST columns were subjected to axial pressure to examine their compaction capacity. The core concrete could be constrained satisfactorily, owing to the high lateral stiffness of the corrugated plate, but the corrugated plate did not bear the axial load. The final form of failure was the local buckling of the steel tube and the outer surface of the corrugated plate; however, the concrete inside the steel tube and the core concrete were crushed. ABAQUS was used to analyze six critical parameters:the concrete strength, thickness of the square steel tube and cross rib corrugated plate, compressive strengths of the square steel tube and cross rib corrugated plate, and section size of the steel tube. The results show that if the concrete strength increases, the load-bearing capacity increases, but the ductility decreases. An increase in the thickness of the steel pipe improves the load-bearing capacity and ductility. The stronger the steel tube, the higher the capacity. The addition of a corrugated plate with side ribs improves the load and ductility. A corrugated board with side ribs has no significant effect on the load-bearing capacity, but it improves ductility. With the addition of the steel pipe section, the load-bearing capacity improves. Finally, an equation for calculating the axial-load force of short CPST columns was derived using the Mander et al. formula for calculating the compression strength of concrete and a compound impact variable. The proposed equation is valuable in practice.