装配式预压抗弯型钢梁柱拼接节点及其框架体系动力失效研究

The public buildings involving lifeline engineering, such as school and hospital, have higher seismic requirements. Moreover, it is easy to implement modulization and industrial production. However, the research on industrialized and prefabricated steel structure are more concentrated on low-rise dwellings and less on high-rise buildings. The connection is the keypoint of high-rise prefabricated steel structure. Its construction and performance would have important effect on the feasibility of prefabrication and the overall property of the structure. The preloaded moment-resistant spliced joint using prestressed screw is proposed in prefabricated connection. In this project, the tests and FEM model will be conducted to build the hysteretic model reflecting the ductile fracture of prestressed screw and carry on more accurate evaluation of failure mode and failure process. Based on the impact of spliced rigidity on second order effect of steel frame, the corresponding seismic design method is proposed. The multi-scale model considering the energy dissipation characteristic of spliced beam joints, spliced column joints as well as shear zone will be established to analyse the severe earthquake resistant behavior of steel frame. The multipoint constraint method will be used to achieve compatible distortion between different size models and force transmission. The multiscale model will be further validated by load-transferring mechanism of joints. Then, the influencing factors on dynamic failure of prefabricated steel frame will be get based on the damage mechanism of structural members and spliced joints performance. Some design suggestions will be given for the high-rise prefabricated steel frame.

学校、医院等公共建筑涉及生命线工程，抗震设防要求高于一般建筑，且易于实现模数化和工业化生产，而我国对工业化装配式钢结构的研究多集中于低层住宅，鲜有多高层装配式钢结构的研究。节点连接构造及性能直接影响结构装配的可行性及整个装配式体系的抗震性能。本课题将预应力拉杆应用于拼装节点中形成装配式预压抗弯型钢梁柱拼接节点。通过试验和有限元实体模型，建立能够反映预应力拉杆塑性阶段的延性断裂特性的节点滞回模型，对结构的破坏模式和破坏过程进行更准确地评估；考虑钢柱拼接刚度的变化对整体钢框架的二阶弯矩的影响，研究考虑二阶效应的装配式钢框架抗震设计方法；建立能充分反映梁、柱拼接节点以及节点域剪切耗能特征的多尺度模型，采用多点约束连接方法实现不同尺寸模型间的变形协调和力传递，并从节点传力机理的角度证明模型的合理性。从而得到罕遇地震下构件和体系损伤机理及拼接节点性能对整个装配式钢框架动力失效的影响，并提出设计建议。

钢结构易于实现模数化和工业化生产，发展全寿命绿色建筑及工业化装配式钢结构体系是我国建筑业向绿色化、工业化转型升级的必由之路。目前我国对工业化装配式钢结构的研究多集中于低层住宅，鲜有多高层装配式钢结构的研究。而节点连接构造及性能直接影响结构装配的可行性及整个装配式体系的抗震性能。为此，本项目研究一种装配式预压抗弯型梁柱拼接节点，即将预应力拉杆应用于拼装节点中形成。在考虑节点传力、耗能机理和预应力度因素后，完成节点性能的影响因素研究，通过参数分析确定了装配式节点预应力张拉力与耗能的关系，以及在循环荷载作用下的力学行为、传力机理、破坏模式以及连接部件的受力和变形特点；建立了能够反映预应力拉杆塑性阶段的延性断裂特性的节点滞回模型，对结构的破坏模式和破坏过程进行更准确地评估；考虑节点破坏发展的装配式钢框架动力分析，完成结构变形模式、屈服机制和破坏机理分析，得到自振特性、变形能力、刚度退化、滞回性能等更为准确的整体钢框架的动力参数；分析了处于弹性工作状态的节点在正负弯矩作用下的法兰板等效刚度、连接法兰板的高强度螺栓抗拉刚度、节点域轴压柱腹板刚度等组件刚度模型。并将相应组件并联或串联，得到拼接节点初始转动刚度的理论计算式。