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为研究径厚比对大直径钢管混凝土柱抗震性能的影响,进行了2个直径600 mm圆钢管混凝土柱试件在恒定轴向压力和水平往复荷载作用下的加载试验,对比分析了不同径厚比(分别为37.5、50.0)试件的破坏形态、滞回特性、钢管应变发展规律以及核心配筋的受力情况。试验结果表明:大直径钢管混凝土柱在压弯荷载作用下,滞回曲线非常饱满,耗能性能优越,均表现出良好的变形能力。随着试件径厚比加大,最大位移角与等效阻尼比均略有减小。柱根部混凝土压溃、钢管鼓曲主要发生在支座底板与下部第一排栓钉之间,栓钉对管壁面外变形具有明显的约束作用;当径厚比较小时,钢管管壁对混凝土的约束作用较强,残余变形较小。核心纵向钢筋基本处于弹性状态,箍筋未屈服,对内部混凝土的约束作用较小,但钢筋与混凝土之间存在明显的滑移现象。大直径钢管混凝土压弯构件的受弯承载力试验值显著高于按照我国现行相关规范、规程公式得到的计算值,说明采用我国现行相关技术规范中的承载力计算公式进行大直径钢管混凝土柱设计,结果偏于安全。
In order to study the influence of aspect ratio on the seismic performance of large diameter concrete filled steel tubular columns, two 600 mm CFST columns under constant axial compression and horizontal reciprocating loads were tested. (37.5, 50.0 respectively) failure morphology, hysteretic characteristics, the development of steel pipe strain and the force of the core reinforcement. The test results show that the large-diameter concrete filled steel tubular columns under buckling load have very full hysteresis curve and excellent energy dissipation performance, all showing good deformation capacity. As the diameter-thickness ratio increases, the maximum displacement angle and equivalent damping ratio decrease slightly. Column root concrete crushed, drum buckling occurs mainly in the bottom plate and the bottom of the first row of pegs between the pegs on the tube wall deformation has obvious restraint; when the diameter is relatively small, the steel pipe wall to the concrete Strong restraint, residual deformation smaller. The core longitudinal reinforcement is basically in elastic state, the stirrups do not yield, the restraining effect on the internal concrete is small, but there is obvious slip phenomenon between the reinforcement and the concrete. The test values of flexural capacity of CFST members with large diameter are obviously higher than those calculated according to the relevant codes and regulations in our country, indicating that the design method of large-diameter concrete filled steel tubular columns with the formula of bearing capacity in current relevant technical specifications The result is biased towards safety.