预制混凝土框架狗骨式型钢连接节点抗震性能研究

Precast concrete frames have many advantages, such as increased speed of construction, reduced site formwork and support, and good durability. However, few types of connection, and lack of appropriate design guidelines, etc., have been a major bottleneck for the extension and implication of precast concrete frames. The project aims to introduce dog-bone section steel connecton to precast concrete frames, which was employed to shift the plastic hinge away from the column face so as to further improve the seismic behavior of precast concrete frames. Seismic behavior of precast concrete frame joints with dog-bone section steel connection was investigated in terms of damage process, energy dissipation, optimal failure mode, restoring force model, etc. in a systematic way through multi-parameter full-scale pseudo-static tests, and stress characteristics in the whole process were revealed, and the failure and energy dissipation mechanisms were clarified. The main factors affecting the seismic behavior were studied in depth by nonlinear finite element analysis , and details of seismic design of connection were optimized. Control parameters of dog-bone section steel connection and design method for precast concrete frame joints with dog-bone section steel connection were proposed based on results of the tests and theoretical analysis, which were instructive for design and construction.

预制混凝土框架结构具有施工速度快、节省模板和支撑、耐久性好等优点。然而，节点连接形式单一、缺乏相应的设计指南等问题已成为制约预制混凝土框架结构推广应用的主要瓶颈。本项目旨在将狗骨式型钢连接形式用于预制混凝土框架结构，使梁端塑性铰外移以进一步提高预制混凝土框架结构的抗震性能。通过多参数足尺节点的拟静力试验，系统研究预制混凝土框架狗骨式型钢连接节点的抗震性能，重点对其损伤过程、耗能性能、最优破坏模式、恢复力模型等进行研究，揭示其全过程受力特征，阐明其失效机制及耗能机理。通过有限元分析，深入研究影响其抗震性能的主要因素，优化连接的抗震构造措施。结合试验与理论分析结果，提出狗骨式型钢连接的设计控制参数以及预制混凝土框架狗骨式型钢连接节点的设计方法，为预制混凝土框架狗骨式型钢连接节点的设计和施工提供理论和技术支撑。

框架节点是结构中关键受力部位，节点连接形式对施工效率、造价、结构可靠性有重要影响。本项目开展了8个足尺节点的单调静力和低周往复荷载试验，系统研究了梁端构造不同对节点刚度、破坏形态、滞回曲线、位移延性、耗能能力等的影响。研究表明：(1) 梁柱间采用端板-螺栓连接时的节点刚度与焊接对比节点基本一致，说明采用端板-螺栓连接的节点也可以是刚性的；(2) 梁端采用狗骨型削弱对节点刚度的影响较小，基本可忽略不计；(3) 梁端有局部约束对节点的弹性刚度影响较小；(4) 梁端的局部约束有助于提高节点的延性；(5) 梁端的局部约束有助于提高节点的耗能能力。研究结果可为钢结构节点和预制混凝土节点设计提供数据支持。