Abstract

The mechanical properties of connection joints and the fire protection design of steel structures are crucial for ensuring structural safety. The utilization of fire-resistant steel in steel structure joints represents a novel approach to enhance fire resistance. In this study, a test on two welded–bolted hybrid connection joints between fire-resistant steel columns and beams was conducted considering both ambient and elevated temperatures. Through an analysis of the failure modes, load–vertical displacement curves, moment–rotation curves, and load–strain curves of the joints, key parameters such as the ultimate bearing capacity, ductility, and deformation capacity were determined. The test results showed that the ultimate bearing capacity of specimen Joint-2-ET at an elevated temperature is 81.14% that of specimen Joint-1-AT at an ambient temperature. While the temperature increases during fire had little effect on the initial stiffness of the joint, it significantly reduced the rotation capacity and ductility of the joint. A finite element model of the joints was developed using ABAQUS software, and its accuracy was validated by comparing the results with the experimental findings. Additionally, a parametric analysis was conducted to explore the effects of temperature and heating region on the mechanical performance of these welded–bolted hybrid connection joints. The outcomes of this research provide valuable insights for engineering applications involving welded–bolted hybrid connection joints between fire-resistant steel columns and beams.

中文翻译：

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耐火钢柱与梁焊接-螺栓混合连接接头在火灾下的力学性能

摘要

钢结构连接接头的力学性能和防火设计对于保证结构安全至关重要。在钢结构节点中使用耐火钢代表了一种增强耐火性能的新方法。在这项研究中，考虑了环境温度和高温，对耐火钢柱和梁之间的两个焊接螺栓混合连接接头进行了测试。通过对节点的破坏模式、载荷-竖向位移曲线、力矩-旋转曲线、载荷-应变曲线的分析，确定了节点的极限承载力、延性、变形能力等关键参数。试验结果表明，高温下Joint-2-ET试件的极限承载力是常温下Joint-1-AT试件的81.14%。虽然火灾期间温度升高对接头的初始刚度影响不大，但它显着降低了接头的旋转能力和延展性。利用ABAQUS软件建立了接头的有限元模型，并通过将结果与实验结果进行比较来验证其准确性。此外，还进行了参数分析，以探讨温度和加热区域对这些焊接螺栓混合连接接头机械性能的影响。这项研究的结果为涉及耐火钢柱和梁之间的焊接螺栓混合连接接头的工程应用提供了宝贵的见解。