不同构造五边形钢管混凝土巨型柱轴压性能计算分析

基于某超高层建筑五边形钢管混凝土巨型柱,研究了不同截面构造五边形钢管混凝土巨型柱的轴压性能。进行了3个五边形钢管混凝土巨型柱试件的单向重复轴压性能试验,试件分别为设钢筋笼单腔体截面、无钢筋笼四腔体截面和设钢筋笼四腔体截面。得到了轴力-位移骨架曲线,分析了损伤破坏过程、残余变形和弹塑性耗能性能,提出了适用的极限承载力计算方法。用ABAQUS软件进行了有限元模拟,分析了截面构造参数(腔体数、有无钢筋笼)对试件受力性能的影响,计算结果与试验符合较好。研究表明:四腔体截面试件与单腔体截面试件相比,承载力和延性明显提高,残余变形较小,耗能能力较强;四腔体试件中腔体内设钢筋笼的试件与不设钢筋笼的试件相比,承载力、延性、耗能能力进一步提高,残余变形减小。四腔体设钢筋笼的五边形钢管混凝土巨型柱综合抗压性能良好,可用于超高层结构设计。

ANALYSIS ON AXIAL COMPRESSION BEHAVIOR OF PENTAGONAL CFST MEGA COLUMNS

Based on the pentagonal concrete filled steel tubular (CFST) mega columns of a super high-rise building, axial compressive behavior of pentagonal CFST mega columns with different cross-sections and detailing were studied. Monotonic cyclic loading tests of 3 pentagonal CFST mega column specimens were conducted under axial compression. 3 specimens were respectively: a single-caved section with a reinforcement cage, a quadruple-caved section without reinforcement cage and a quadruple-caved section with reinforcement cages. Axial force-deformation curves were obtained. The failure mechanisms, residual deformation and elastic-plastic energy dissipation capacities were analyzed. Methods for calculating the ultimate bearing capacity of CFST mega columns were proposed. Finite element simulations are carried out based on ABAQUS for analyzing the effects of cross-sectional and detailing parameters, including the number of cavities and the presence of reinforcement cages on member behavior. The simulation results agree well with the test results. It is concluded that quadruple-caved sections have greatly increased the bearing capacity and ductility with less residual deformation and better energy dissipation capacity compared with single-caved sections. Additionally, quadruple-caved sections with reinforcement cages have further increased the bearing capacity, ductility, and the energy dissipation capacity with even less residual deformation compared with quadruple-caved sections without reinforcement cages. Pentagonal CFST mega columns with quadruple-caved sections and reinforcement cages have comprehensively good compressive behavior, which can be used in the design of super high-rise buildings.