带垫板的双肢C型钢框架抗震性能研究

The seismic behavior and thermal insulation performance of double C steel with gusset plate used for the structure's load-bearing components to build multi-storey and light-duty housing is superior to the ones of traditional civil structure construction. The frame structure of double C steel with gusset plate was studied by combing the methods of theoretical analysis, experiment and finite element simulation. Considered the influencing factors of natural vibration period, formation, inner force and inter-story lateral displacement of the frame, the anti-seismic performance of capacity spectrum, plastic hinge distribution, the hinge sequence under different joint rigidity and the lateral load distribution are studied, and the horizontal load distribution of frame are solved. The impacts of C steel model, gusset plate thickness ,bolt spacing, component slenderness ratio and axial compression ratio on failure mechanism, failure characteristics, hysteretic performance, ductility, stiffness degradation and ultimate bearing capacity were studied. Compared ANSYS models of microstructure with macrostructure models, a kind of practical analysis method applied to rare earthquake was proposed. Considered the contribution of the diaphragm effect and supporting system to frame stiffness, it could provide a reliable basis on reducing supports for practical engineering design.

冷弯薄壁C型钢作为结构的承重构件，建造多层轻型房屋，其抗震、保温等性能优于传统土木结构建筑。选取带垫板的双肢C型钢框架结构为研究对象, 采用理论、试验和有限元相结合的方法，考虑框架的自振周期、阵型、内力及层间侧移等特性，分析不同节点刚性下框架的能力谱、塑性铰分布、出铰顺序等抗震性能，适合该框架结构的侧向荷载分布形式，解决该框架的水平荷载分配问题。研究C型钢型号、节点板厚度、螺栓间距、构件长细比和轴压比等因素对框架的破坏机理、破坏特征、滞回性能、延性、刚度退化和极限承载力等抗震性能的影响。对比ANSYS微观结构模型和宏观结构模型，提出一种适用于罕遇地震的实用分析方法。考量蒙皮效应和支撑体系对框架刚度的贡献，可以为实际工程设计中减少支撑设置提供可靠的依据。

内插热轧钢板和高强螺栓连接解决了冷弯C型钢构件的连接问题，建立了双肢冷弯C型钢“非盒子式”的框架结构（后简称框架），改善了传统低层冷弯型钢房屋结构的传力机制。所构建的框架结构抗震性能好，属于半刚性框架范畴。.框架破坏模式为伴随梁端和柱脚局部屈曲的整体破坏。在所研究的设计参数范围内，节点板厚度、螺栓直径、支撑设置、轴压比和梁柱线刚度比会影响框架的破坏形态，提出节点板厚度取6mm以上，螺栓直径不小于20mm，弱支撑设置，轴压比不大于0.4和梁柱线刚度比不小于0.4的设计要求，可以满足“强柱弱梁、强节点弱构件”的抗震设计要求。柱长细比、轴压比、腹板高厚比、梁柱线刚度比、节点板加腋及C型钢的厚度对框架承载力、刚度和耗能影响显著；螺栓间距对框架节点性能影响较大，但对框架的承载力没有直接影响；设置钢板墙可以提高框架的承载能力，变形能力也优于设置刚性交叉支撑的框架。.通过函数拟合强化刚度与弹性刚度比、负刚度与弹性刚度比、屈服荷载与极限刚度比、极限荷载与框架参数的函数关系，建立了具有95%置信度的框架恢复力模型。整理出一套便于实际工程中精细化抗震分析的APDL语言模块，通过参数设定本构关系、模型单元与网格、加载求解等可进行框架的罕遇地震分析。低层框架不同地震条件下模态分析和时程分析发现在框架薄弱层的塑性转角可能超过规范限值，设置支撑会改变框架破坏模式，而设置蒙皮得到明显改善。分析不同蒙皮参数下框架的结构响应，明晰了蒙皮参数对框架抗震性能的影响。.框架反应谱及静力弹塑性分析得到了不同节点刚度条件下框架的层间转角、层间位移、顶点位移及底部剪力等，对比Pushover曲线与反应谱分析响应结果，确定均布荷载分布为最适合框架抗震分析的水平荷载分布方式。框架能力谱与ADRS需求谱分析其性能点，评价了框架的抗震性能。