外包钢管-对拉钢筋式装配式混凝土框架节点数值分析

文章设计构造了一种新型外包钢管-对拉钢筋式装配式混凝土框架节点, 并进行低周反复荷载试验研究。试验共设计 4 个足尺节点试件, 研究外包钢管厚度和在节点核心区设置补强板对节点承载力和刚度的影响。基于已有的试验研究结果, 建立 ABAQUS 有限元模型, 对节点在循环荷载作用下的力学性能与破坏模式进行模拟, 对节点受力机理进行分析。模型中采用混凝土塑性损伤本构模型、钢筋双折线弹塑性模型、钢结构混合强化本构模型, 并定义钢材柔性损伤。对比试验结果可知该模型准确地模拟出节点承载力退化以及滞回曲线的捏缩, 验证了模型损伤准则的适用性。对模型的耗能与刚度退化进行分析, 进一步探究了对拉钢筋直径、外包钢管延伸高度、轴压比等参数对节点力学性能的影响。

In this paper, a new type of precast concrete frame joints with wrapped steel tube and tie-bar was designed and constructed, and low cyclic loading tests were conducted. A total of four full-scale joints were designed for the tests, and the effects of the thickness of the wrapped steel tube and the reinforcement plate in the core area of the joints on the joint bearing capacity and stiffness were studied. Based on the existing experimental research results, the ABAQUS finite element model was established to simulate the mechanical properties and damage modes of the joints under cyclic loading, and to analyze the force mechanism of the joints. In the model, a plastic damage constitutive model of concrete, a bilinear elastoplastic model of steel reinforcement, and a mixed strengthening constitutive model of steel structure were adopted with the definition of steel flexible damage. The comparative test results show that the model accurately simulates the degradation of joint bearing capacity and the pinching of hysteresis curve, verifying the applicability of the model damage criterion. The energy consumption and stiffness degradation of the model were analyzed, and the effects of parameters such as the diameter of the tie-bar, the extension height of the wrapped steel tube, and the axial compression ratio on the mechanical properties of the joints were further investigated.