【作者】 黄频；

【导师】 何益斌；

【作者基本信息】 湖南大学 ， 结构工程， 2011， 博士

【摘要】 综合型钢混凝土结构和钢管混凝土结构的优点后,将钢骨置入圆(方)钢管中,然后浇注素混凝土,形成一种新型的组合柱形式——钢骨-圆(方)钢管混凝土柱。目前对此种组合柱的力学性能有了较为深入的研究,然而对其节点的研究却相对滞后很多。鉴于此,本文借鉴钢结构中常用的端板螺栓节点,将其引入组合结构中,用贯穿柱身的双头等长高强度螺栓将端板与钢骨-方钢管混凝土柱连接在一起,钢梁焊接在端板上,从而形成一种新型的组合节点形式。本文在总结传统钢-混凝土组合节点的基础上,对此种新型节点的力学性能进行了较为深入的试验与理论研究并提出了其设计方法。主要研究内容如下：(1)设计并进行了7个钢骨-方钢管混凝土柱-钢梁端板螺栓连接节点的拟静力试验研究。研究了这种新型节点在梁端低周反复荷载作用下的宏观变形特征、破坏机理、破坏模式以及延性、强度退化、刚度退化和耗能能力等抗震性能指标,同时较为系统地研究了轴压比、端板厚度、螺栓直径、混凝土强度对组合节点受力性能的影响规律,并建立了钢骨-方钢管混凝土柱-钢梁端板螺栓节点的恢复力模型,为结构的弹塑性时程分析提供了依据。(2)运用ANSYS对试验中的7个试件进行了全过程有限元分析,分析中考虑了几何非线性、材料非线性和状态非线性等复杂非线性问题。通过与试验结果的对比,验证了有限元方法分析端板螺栓连接组合节点的可靠性。经过计算分析得到了节点域核心混凝土受力特点、节点主应力流的大小及分布、端板与柱翼缘之间接触压应力分布特征等,弥补了试验测试的局限性,从而获得对此类新型节点受力特性更准确、更全面的认识。(3)对钢骨-方钢管混凝土柱-钢梁端板螺栓连接节点核心区的受力机理进行了分析,建立了节点核心区的受力模型和屈服机制,推导了节点域的抗剪承载力计算公式,并根据剪切变形协调条件得到了节点域剪力-剪切变形骨架曲线,为此类节点的工程设计提供了简化计算方法。(4)考虑了螺栓预拉力作用下板件对螺栓变形的影响,将高强螺栓和受压板件简化为一“栓板单元”,推导得到了栓板单元的刚度计算表达式,并根据螺栓在各个阶段的受力特征,计算得到了螺栓的承载力及变形,建立了节点弯矩-螺栓伸长转角曲线。(5)基于屈服线理论和薄板理论分别计算了端板在不同支撑条件下的承载力和初始刚度,并提出了端板全过程受力特性的理论分析方法。(6)基于叠加原理提出了一种钢骨-方钢管混凝土柱-钢梁端板螺栓连接节点全过程受力特性的理论分析方法,直接由节点的构造尺寸和材料力学性能便可进行计算分析,避免了复杂的有限元分析计算和试验研究,理论得到的弯矩-转角曲线与试验结果吻合良好。如在实际框架结构的弹塑性计算分析中,将本文提出的弯矩-转角模型应用到结构的计算模型中,能更好地了解节点受力性能对结构整体的影响,从而为今后的科学理论研究和工程实践提供参考。(7)在总结试验研究结果、有限元和理论分析成果的基础上,同时结合国内外相关研究成果和规范,针对钢骨-方钢管混凝土柱-钢梁端板螺栓节点提出了较为系统的静力和抗震设计方法,为我国钢-混凝土组合结构的推广应用提供了有益补充。此外,应用组件法建立了此类新型节点初始转动刚度计算的力学模型,并由此推导出节点初始转动刚度的计算表达式,以便在组合框架结构弹性设计时使用。更多还原

【Abstract】 Steel-reinforced concrete filled steel tubular columns formed by inserting structural steel into concrete-filled circular (square) steel tubes, is a new type of modern composite column. This type of composite column has the advantages of both steel-reinforced concrete structures and concrete filled steel tube structures. There has been a lot of research about the mechanical behavior of the composite column, but the research on its connection is relatively backward. In view of the above-mentioned situations, the bolted end-plate connections, commonly used in steel structures, is introduced in composite structure this dissertation. This new type of connection is formed by end-plate and steel-reinforced concrete filled square steel tubular columns joined together using high strength bolt with equal-length in both ends, and the steel beam is welded on the end-plate. In this dissertation, the mechanical properties and design method of this new type connection have been extensively investigated both experimentally and theoretically based on previous research achievements of steel-concrete composite connections. The main contents are as follows:1.7specimens of steel beam-to-steel-reinforced concrete filled steel tubular column bolted end-plate connections are designed and tested under cyclic loading. Macroscopical deformation characteristics, failure mechanism, failure modes, ductility, strength degradation, rigidity strength degradation, energy dissipation of this new type connection under low reversed cyclic loading are observed and studied. Influences of the axial compressive ratio, thickness of end-plate, bolt diameter, concrete strength grade on the bearing capacity of the composite connections are investigated. Hysteretic model for these end-plate connections to square steel tube columns filled with steel-reinforced concrete is also constructed according to experimental results, which can be used in the elasto-plastic time-history analysis of structural system.2. The nonlinear finite element analysis (FEA) of7specimens is carried out using ANSYS program, and some complicated nonlinear problems are considered in the analysis, such as geometric nonlinear, material nonlinear and state nonlinear. With comparison to the test results, it is verified that finite element method can efficiently simulate and analyze the bolted end-plate composite connections. Some characteristics of end-plate connections which are difficult to be measured by tests, such as the stress characteristics of concrete in panel zone, the magnitude and distribution of primary stress and the distribution characteristics of contact compressive stress between the end-plate and coloumn flange can be gained in FEA analysis. Therefore, FEA method can reflect the mechanical behavior of connections in a more complete and accurate way.3. According to theoretical analysis and test results, the mechanism of force transfer in panel zone is analyzed, and a mechanical model is established in order to derive theoretical equations for calculating the shear capacity of the panel zone. And skeleton curves of shearing force and shear deformation for the panel zone in end-plate connections are obtained in the condition of coincident deformation, which accommodates a brief calculation method for engineering design.4. Considering the effect of plate to the deformation of the bolt under pre-stress, the high strength bolt and compressive plate are idealized as a "bolt-plate element" the calculation formula of the rigidity for the "bolt-plate element" is deduced. The bearing capacity and deformation are calculated according to mechanics character of the bolts in each stage, and the moment-rotation curve of the high strength bolt is established.5. Based on the theory of yield line and thin plates, bearing capacity and initial stiffness of the end-plate under different supporting conditions are calculated, and theory analysis method of complete loading process of the end-plate is proposed.6. A theretical analysis model is presented for analyzing the complete loading process of the bolted end-plate connections on the basis of the superposition principle. The moment-rotation curves can be derived directly from construction dimension and material properties, and avoids the complicated finite element analysis and experimental research. The calculated moment-rotaion curves agree well with the experimental results. In elasticity-plasticity analysis of actual framework structure, if the moment-rotation model presented in this dissertation can be applied to structure analysis model, the influence of connection behavior on the whole structure can be well understood so that it can provide a reference for the design and research in the future.7. A complete set of static and seismic design method for semi-rigid end-plate connections are proposed on the basis of achievements of aforementioned cyclic loading tests research, the finite element analysis and relative research achievements. These are all beneficial supplements to the popularization and application of the steel-concrete composite structure. Mechanical model for calculating initial rotational stiffness of the end-plate connections is established by using component methord. According to the mechanical model, the calculation formula for initial rotational stiffness of the end-plate connections is deduced which can be used in elastic design of composite framework structure.更多还原