基于损伤累积的火灾后钢管混凝土柱-钢梁空间节点抗震机理研究

钢管混凝土在地震区高层、超高层、地下结构等工程中应用广泛，但对其火灾后结构的抗震性能方面的研究并不多见，严重影响了火灾后结构的安全。本项目拟系统研究基于损伤累积的火灾后钢管混凝土柱-钢梁空间连接节点的抗震机理。建立考虑受火、受力全过程的火灾后结构精细化有限元分析模型，开展火灾后钢-混凝土界面滞回性能试验和火灾后空间节点的抗震性能试验，深入分析火灾后节点核心区约束效应和协同工作性能的变化、火灾后节点的地震失效演变机理、以及空间效应、施工荷载、长期荷载、组合楼板等因素对节点性能的影响，在此基础上建立火灾后节点剩余刚度、承载力和抗震性能评估方法，为工程应用提供科学依据。项目开展有助于提升火灾后钢管混凝土结构的安全水平，具有重要的理论意义和工程实用价值。本项目研究内容新颖，技术路线和方案合理可行，前期工作基础扎实，完全具备完成好课题的各项条件。

The concrete-filled steel tube is widely used in high-rise, super high-rise, underground structures and other engineering projects in earthquake-prone zones. However, research on its mechanical properties after fire, especially the post-fire seismic performance is rare. This project intends to systematically study the mechanism of concrete-filled steel tubular column-steel beam space joints under seismic loading after exposure to fire based on damage cumulation. The finite element analysis model of the structure after fire is established with considerations of the whole process of fire and loading. The test is carried out on the hysteretic behavior of steel-concrete interface after fire and the residual seismic performance of space joint after fire. The variation of confinement effect and the performance of interface is analyzed. The damage mechanism of fire-exposed space joint under seismic loading is discussed. The influences of space effect, constructional and long-term sustained loads, and the composite slab on the connection performance are studied. The methods to assess the residual stiffness, the residual strength and the residual seismic performance are proposed. This project will enhance the safety level of post-fire CFST structures, which has important theoretical significance and practical value of engineering. The content of the project is innovative, the technical route is feasible, the preliminary work is solid, and it has a sound foundation for completing the project.