两种新型延性节点在地震和全过程火灾中的性能

Performance of Two Novel Ductile Connections under Extreme Seismic and Fire Loads

摘要: 节点是确保建筑结构在火灾条件下的完整性的最关键的部件。为了提高结构的延性，本研究提出了两种新型的延性节点，即节点原型1和节点原型2，它们具有优越的变形能力。本研究旨在系统分析这些节点在全火灾过程中的性能，包括加热和冷却阶段，并评估其在独立地震作用下的循环响应。首先，详细阐述了新型延性节点的设计。随后，利用ABAQUS建立了与延性连接相结合的钢框架模型，用于研究它们在整个火灾过程(包括加热和冷却阶段)的性能。模型中采用了考虑冷却阶段的ISO-834标准火灾曲线进行热力耦合分析，并编制了自定义子程序VUSDFLD来考虑结构钢和高强度钢在冷却阶段的材料特性。最后，建立了两种延性节点的精细钢框架模型，并对其在反复荷载作用下的抗震性能进行了对比分析。研究结果表明，延性节点在整个受火过程中表现出良好的变形协调性；在循环荷载作用下，延性节点具有饱满的滞回曲线，具有良好的耗能能力和延性系数。研究结果表明，延性连接可以有效地提高桥梁钢框架结构在多险情下的恢复力。

Abstract: Connections are the most critical components for ensuring the integrity of building structures under fire conditions. To enhance structural resilience, this study proposes two novel ductile connections which are prototype 1 and prototype 2 with superior deformation capacity. The research aims to systematically analyse the performance of these connections during the full fire process, including heating and cooling phases, and evaluate their cyclic response under standalone seismic action. First, the design of the novel ductile connections is elaborated in detail. Subsequently, Abaqus is employed to establish a steel frame model integrated with the ductile connections for investigating their performance throughout the complete fire process (encompassing heating and cooling stages). In the model, the ISO-834 standard fire curve, incorporating the cooling phase, is adopted for thermo-mechanical coupling analysis, and the user-defined subroutine VUSDFLD is implemented to account for the material properties of structural steel and high-strength steel during the cooling stage. Finally, refined steel frame models equipped with the two types of ductile connections are developed, and their seismic performance is comparatively analysed under cyclic loading. The research results indicate that the ductile connections exhibit excellent deformation compatibility during the full fire process; under cyclic loading, they feature plump hysteretic curves, along with superior energy dissipation capacity and ductility coefficient. The conclusions demonstrate that the proposed ductile connections can effectively enhance the resilience of steel frame structures in bridges under multi-hazard scenarios.