Super high-rise structures frequently employ concrete-filled steel tubular (CFST) column-steel beam joints with stiffening ring because of its superior performance. This study examined the structural behavior of high axial compression ratio stiffening ring joints with stirrups in the column. Three 1/2-scaled joints with different stirrup arrangements and axial compression ratios were designed and tested. Apart from analyzing the hysteresis behavior, skeleton curve, stiffness degradation, energy dissipation, and steel strain of each specimen, an investigation was conducted into the failure mechanisms of the specimens under low cycle reciprocating load on the beam end. Furthermore, a three-dimensional nonlinear solid finite element (FE) model was developed for the joint. The results of the FE analysis and the experimental data agreed well regarding failure modes, hysteresis curves, and steel strain. Furthermore, the energy dissipation allocation mechanism of joints with various parameters was revealed. The results show that the seismic performance of the stiffening ring joint with stirrups was excellent, and stirrup confinement effectively improved the seismic performance of stiffening ring joints. Under a high axial compression ratio of 0.8, the joint with stirrup exhibited bending failure at the beam end, avoiding the phenomenon of column end bending failure in traditional specimens. In addition, the stiffening ring joint underwent a transition from beam energy dissipation to column energy dissipation when the beam-column flexural capacity ratio reached 1.39. The study's findings can serve as a guide for engineers using stirrups in square CFST column-steel beam joints with stiffening rings.

中文翻译：

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高轴压比下加劲环和箍筋的 CFST 柱-钢梁节点的试验与分析研究


由于其卓越的性能，超高层结构经常采用带有加强环的混凝土填充钢管 （CFST） 柱-钢梁节点。本研究考察了柱内带箍筋的高轴压比加劲环节点的结构行为。设计并测试了三个具有不同箍筋布置和轴压比的 1/2 比例节点。除了分析每个试件的滞后行为、骨架曲线、刚度退化、能量耗散和钢应变外，还研究了试件在梁端低周往复载荷下的失效机理。此外，还为节理开发了三维非线性实体有限元 （FE） 模型。有限元分析结果与实验数据在失效模式、磁滞曲线和钢应变方面吻合较好。此外，揭示了不同参数关节的能量耗散分配机制。结果表明：带箍筋的加劲环节点抗震性能优异，箍筋约束有效提高了加筋环节点的抗震性能;在 0.8 的高轴压比下，带箍筋的节点在梁端出现弯曲破坏，避免了传统试件中柱端弯曲破坏的现象。此外，当梁柱弯曲承载力比达到 1.39 时，加劲环节点经历了从梁能量耗散到柱能量耗散的转变。该研究的结果可以作为工程师在带有加劲环的方形 CFST 柱-钢梁节点中使用箍筋的指南。