钢管混凝土柱-钢筋混凝土梁连接节点抗震性能的机理分析

MECHANICAL ANALYSIS OF REINFORCED BEAM-CFST COLUMN JOINT UNDER SEISMIC LOADING

钢管混凝土结构因其具有良好的延性等抗震性能,在地震荷载作用下,具有较强的抗倒塌能力,使其在工程实践中得到广泛的应用。该文在已有的有限元数值分析模型基础上,通过将不同轴压比下方形和圆形钢管混凝土柱-钢筋环绕式钢筋混凝土梁连接节点的计算滞回曲线、骨架线与试验滞回曲线相比较,验证有限元模型并揭示节点的抗震特性。通过对典型轴压比下钢管混凝土结构节点的工作机理分析,研究受力全过程中节点裂缝和变形发展过程,明确节点极限状态和破坏模态;揭示节点核心区混凝土约束力、钢筋应变、核心区剪力的变化规律。基于比较不同轴压比下节点极限状态的核心混凝土应力和核心区剪力状态,确定轴压比对节点破坏模态的影响。

The concrete-filled steel tubular structure is widely used in practice because it shows perfect seismic performances such as good ductility and strong ability to resist collapse under seismic loadings. The numerically computed hysteresis curves and sketch curves of concrete-filled steel tubular （CFST） column to reinforced concrete beam joint under different axial load levels were compared with experimental results in this paper to verify the accuracy of the finite element model and to reveal the anti-seismic properties of the joint. By analyzing the behavior of CFST joint under typical axial load level, the development of cracks and deformations is studied, and the ultimate state and the failure mode are determined. In addition, the variation of the rebar strain, the concrete constraint force and the shear force in the joint core are obtained. The effect of the axial load level on the failure mode is determined by comparing the stresses in the core concrete and the shear fore in the joint core under different axial load levels at the ultimate state.