单层单跨变截面门式刚架结构梁柱节点与结构整体抗震性能研究

发布时间：2018-01-29 19:15

本文关键词： 门式刚架抗震性能半刚性连接拟静力试验 M-θ模型有限元分析恢复力模型　出处：《西安建筑科技大学》2013年博士论文　论文类型：学位论文

【摘要】：轻型门式刚架结构具有良好的经济效益和抗震性能，在低层建筑中应用广泛。由于自重较轻，地震作用力较小，人们对于该结构的抗震研究较少。但在后来的一些强烈地震中，结构局部仍然会发生一定程度的破坏，严重的局部变形甚至会引起整体结构的倒塌，这引起了人们对其抗震性能研究的重视。本文对1/2缩尺模型端板竖放、平放、斜放螺栓连接节点进行滞回试验研究，每种节点形式3个试件。试验得到了节点的荷载-位移曲线、骨架曲线、刚度退化和螺栓内力分布情况。研究表明：三种形式节点的破坏模式基本相似，均为距梁端约1.5倍梁大头截面高度位置翼缘发生局部屈曲，构件承载力达到峰值后迅速下降，呈脆性破坏形式。试件的荷载-位移滞回曲线饱满程度不高，说明其塑性发展较小，耗能能力较差，地震作用下不能利用其塑性耗能能力，结构设计应按弹性阶段考虑。端板厚度和螺栓强度对节点刚度影响较大，端板越厚，螺栓强度越高，节点刚度越大。但进入弹塑性阶段，端板越厚其刚度退化速度越快。综合考虑三种节点的抗震性能，建议设计时优先考虑使用端板竖放形式。总之，按“规程”设计的节点可满足了“强节点，弱构件”的抗震设计理念要求。本文同时对1/3缩尺模型柱脚铰接端板竖放节点的整体门式刚架结构进行拟静力试验研究，，刚架的破坏模式为形成3个“屈曲铰”的机构：2个铰位于梁的两个端部，1个位于梁跨中截面薄弱处；试验得到了结构的滞回曲线、骨架曲线、刚度、刚度退化及水平位移情况，并利用底部剪力法对其地震承载力进行验算。结果表明：虽然该结构延性、耗能能力较低，难以利用其塑性变形提高抗震性能；但由于结构自重轻，地震作用力小，仍可较好满足抗震设防要求。通过应变数据的分析，发现塑性阶段，近、远端梁应变差异较大，并分析了影响结构整体性能的因素，如局部屈曲、蒙皮效应、楔率、翼缘宽厚比及腹板高厚比等。本文通过有限元软件对试验模型进行验证，并分析了试验模型原型结构的抗震性能，在此基础上进行参数分析，包括翼缘宽厚比、腹板高厚比和楔率对结构抗震性能的影响。研究发现：梁翼缘宽厚比、腹板高厚比及楔率主要影响结构的承载力和耗能情况；柱翼缘宽厚比、腹板高厚比及楔率主要影响结构初始刚度、退化刚度和位移情况。在有限元参数分析结果上，拟合得到结构屈服荷载、峰值荷载与破坏荷载之间的计算公式以及退化刚度、负刚度与初始刚度之间的计算公式。同时，本文提出了一种提高门式刚架整体抗震性能的支撑形式，有限元分析表明：带支撑结构比未设置支撑结构承载力提高10%以上，耗能能力提高1.8倍。在强化双线性模型以及端板竖放节点滞回试验的基础上，建立了该节点的M-θ简化模型，与整体拟静力试验及有限元模型对比发现，该简化模型对结构的屈服荷载与最大荷载计算较准确，具有较高的工程意义。最后，本文提出了考虑翼缘宽厚比、腹板高比及楔率影响的门式刚架退化三线型恢复力模型，与试验结果吻合较好，为该结构的抗震性能分析提供了一种简化方法。根据上述研究结果，对轻型门式刚架节点及整体结构的抗震性能有了较全面认识，可为相关规范修订提供一定依据，并为日后展开更深入的研究奠定基础。
[Abstract]:The light portal frame structure has good economic benefit and seismic performance, widely used in low rise buildings. Due to lighter weight, smaller earthquake force, people for the seismic research of the structure is less. But in some strong earthquake later, local structure may still occur to a certain degree of damage, serious local deformation even caused the collapse of the whole structure, which caused people to pay more attention to the seismic performance research.
In this paper, a 1/2 scale model of vertical end plate, flat, inclined bolt connections were tested to study the hysteretic, each node form of 3 specimens. The test node of the load displacement curve, skeleton curve, stiffness degradation and bolt stress distribution. The results show that: the failure mode of three kinds of form the nodes are similar, both from the end of the beam is about 1.5 times the bulk of beam section height position flange local buckling, peak bearing capacity decreased rapidly after the brittle failure form of specimens. The load displacement hysteretic curve is full degree is not high, the development of plastic energy dissipation capacity is poor, the smaller. Cannot use the plastic energy dissipation capacity under earthquake, the structure design should be considered according to the elastic stage. The thickness of the end plate and bolt strength has great effect on the stiffness of end plate thickness, bolt strength is high, the joint stiffness is greater. But in the elastic-plastic stage, the end plate The faster the degradation of the stiffness is, the more comprehensive consideration is given to the seismic performance of the three joints. It is suggested that the end plate vertical placement should be considered in the design. In conclusion, the nodes designed according to the "rules" can satisfy the requirements of the seismic design concept of "strong nodes and weak components".
This paper also put the whole portal node on the 1/3 scale model of hinged vertical end plate frame structure of pseudo static test, the failure mode of the frame for the formation of 3 "buckling hinge" mechanism: the two ends of the 2 hinge in beam, 1 in the mid span section is weak; test the hysteretic curve, skeleton curve, stiffness, stiffness degradation and horizontal displacement, and the checking of bearing capacity of the earthquake using the bottom shear method. The results show that although the ductility, energy dissipation capacity is low, it is difficult to use the plastic deformation to improve the seismic performance; but due to the structure of light weight the earthquake force, small, can better meet the anti-seismic requirements. Through the analysis of the strain data, found that the plastic stage, near the distal beam strain differences, and analyzes the factors affecting the overall performance of the structure, such as local buckling, skin effect, wedge ratio, flange width The thickness ratio and the thickness ratio of the web.
In this paper, to verify the test model by finite element software, and the analysis of the seismic performance test model of the prototype structure, based on the analysis of parameters, including the flange slenderness ratio, web depth thickness ratio and wedge ratio influence on seismic performance. The study found that: the flange width thickness ratio, web thickness ratio and high rate of wedge the main effect of the bearing capacity and energy dissipation structure; column flange slenderness ratio, web depth thickness ratio and wedge rate mainly affects the initial stiffness, stiffness degradation and displacement. The finite element analysis results in parameter fitting structure, yield load, peak load and the calculation formula between the failure load and stiffness degradation. Negative stiffness and initial stiffness between the calculation formula proposed in this paper. At the same time, support for improving the overall seismic performance of portal frame, finite element analysis showed that the supporting structure than the support structure is not set The bearing capacity is raised by more than 10%, and the energy dissipation capacity is increased by 1.8 times.
In strengthening the bilinear model and vertical end plate connections hysteretic test based on the set up of the node M- theta model, and found the whole quasi comparative static test and finite element model, the simplified model of yield load structure and maximum load calculation is more accurate, and has high engineering significance. Finally, this paper considering the flange slenderness ratio, web portal effect and high rate of wedge frame three linear force restoring model agree well with the experimental results, provides a simplified method for analysis of seismic performance of the structure.
According to the above results, a more comprehensive understanding of the seismic performance of portal frame and the overall structure of the node, can provide certain basis for the revision of relevant norms, and for the day after more study to lay the foundation.

【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU392.5;TU352.11

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