【作者】 徐国林；

【导师】 张令心；

【作者基本信息】 中国地震局工程力学研究所 ， 结构工程， 2009， 博士

【摘要】 巨型钢框架结构是一种具有巨大抗侧移刚度及整体工作性能的大型结构形式，由于结构布置灵活、节省材料、充分发挥材料强度和有利于抗震等特点，在近几十年来得到了广泛的应用。在罕遇荷载作用下，结构中常常会出现杆件屈服，需要对结构进行非线性分析。巨型钢框架结构中格构式巨型梁和巨型柱构成复杂，其杆件非线性分析模型及结构的非线性分析方法均未得到很好的解决。因此，本文对巨型钢框架结构精细和实用的非线性分析方法及其应用进行了深入研究，为此类高层建筑地震反应分析、抗震性能及抗震设计方法提供有效的分析手段。主要工作如下：系统地总结和评述了现有巨型钢框架结构三维非线性分析方法及其优缺点，为本文的研究奠定了基础。选用具有良好精度和计算效率的4节点减缩积分壳单元对巨型构件进行离散，建立分析模型，给出了基于三维壳单元模型巨型钢框架非线性地震反应分析方法，并利用大型有限元程序MSC.Marc加以实现，采用其并行运算技术减缩了计算耗时。该方法作为精细分析方法可用于构件及节点的受力特性研究以及小型结构的非线性反应分析。本文采用该方法对巨型柱支撑形式进行了研究，选用不同长细比的支撑杆件，对比了常用三种支撑形式巨型柱的刚度、延性和耗能能力，给出了巨型柱中支撑形式选取的建议。将Timshenko梁理论与纤维模型相结合，以刚度法为基础推导了单元刚度矩阵，建立了能够考虑剪切屈服与弯曲屈服相分离的纤维模型，实现了剪切变形对杆件刚度的影响。通过二次开发接口，将此单元刚度矩阵嵌入到有限元软件MSC.Marc程序中，给出了基于Timshenko梁理论纤维模型的巨型钢框架结构非线性地震反应分析方法。采用V.Mises屈服条件，关联塑性的V.Mises流动法则和Zeigler增量随动强化准则推导了能够考虑一个主应力、两个剪应力和扭转应力的材料弹塑性矩阵，在此基础上，推导了基于Timshenko梁理论有限分割塑性区模型单元刚度矩阵，通过二次开发接口，将此单元刚度矩阵嵌入到有限元软件MSC.Marc程序中，给出了基于有限分割塑性区模型的巨型钢框架结构非线性地震反应分析方法。采用本文所给的三种巨型钢框架结构非线性地震反应分析方法，对深梁和短梁构件进行计算精度和效率的对比分析，结论表明，Timshenko梁纤维模型可作为巨型钢框架结构非线性地震反应分析的实用方法。采用该方法对一栋实际巨型钢框架结构进行了非线性地震反应分析，以此算例说明了该方法的适用性。更多还原

【Abstract】 Steel mega-frame structures are large-scale structure, which has hugelateral resistance stiffness and overall performance. In recent decades, it hasbeen broadly used because of its flexible layout, less material consuming, fullytaking advantage of material strength and well seismic behavior. Under the rareseismic load, some elements tend to yield, so the nonlinear analysis of structuremust be conducted. The composition of the mega beams and mega columns inthe steel mega-frame structure are complex. The proper nonlinear analyticalmodels of elements and nonlinear analytical methods of structure have not beensolved. In this paper, theprecise and practical methods of the nonlinear analysisof the steel mega-frame structures and their applications are studied, whichprovide effective tools for seismic response analysis, seismic performanceresearch and seismic design of this kind of structures. The main work includes:The current 3-D nonlinear analytical methods of steel mega-framestructures and their vantage and disadvantage have been systematically reviewedand summarized, which lay the foundation for the research work in this paper.A 4-node reduced integration shell element, which has high accuracy andcomputation efficiency, is adopted to discrete the mega elements and establishthe analytical model. The nonlinear seismic response analysis method of steelmega-framestructures based on 3-D shell element model is given, and the FEMsoftware MSC.Marc is used to achieve the method. The parallel computationtechnique is explored to reduce the computing time. The method can be used asa precise analytical method for the mechanical behavior analysis of the elementsand nodes or the nonlinear analysis of small-scale structures. The method wasused to study the bracing types of the mega columns. Selecting bracing barswith various length to slenderness ratios, comparing the stiffness, ductility andenergy absorption ability of the mega columns with three common bracing types,the suggest of bracing type choice is given.Combining Timoshenko beam theory and fiber model, the element stiffnessmatrix can be derived based on stiffness method. And the fiber model whichconsiders shear yielding and flexural yielding separately is established. Theinfluence of element stiffness from shear deformation is achieved. The stiffnessmatrix of Timshenko beam-fiber model can be implanted into softwareMSC.Marc by the second development interface. Thus the nonlinear seismicresponse analysis method of steel mega-frame structures based on Timoshenkobeam-fiber model can be realized. Using V. Mises yielding conditions, plasticity-related V. Mises flow lawsand Zeigler incremental strengthening laws, the material elastic-plastic matrixwhich can consider one principle stress, two shear stresses and torsional stresseshas been derived. On the basis, the finite segment element plastic zone stiffnessmatrix was built based on Timoshenko beam theory. This stiffness matrix can beimplanted into software MSC.Marc by the second development interface. Thusthe nonlinear seismic response analysis method of steel mega-frame structuresbased on the finite segment element plastic zone can be realized.The three methods given by this paper is used to analyze the nonlinearresponse of deep beams and short beams. Though comparing computationaccuracy and efficiency, the method based on Timshenko beam-fiber model isregarded as a practical method of nonlinear seismic response analysis method ofsteel mega-frame structures. And the method was used in nonlinear seismicresponse analysis of an actual mega-frame structure to illustrate the applicabilityof the method.更多还原