【作者】 刘洁平；

【导师】 张令心；

【作者基本信息】 中国地震局工程力学研究所 ， 防灾减灾工程及防护工程， 2003， 硕士

【摘要】 本文首先介绍了巨型结构及其特点，着重总结、论述了巨型钢结构的力学模型和分析方法及其抗震研究发展现状，指出了这种钢结构体系抗震研究中存在的主要问题，和今后需要进一步研究的方向。 在此基础上，深入研究了楼板刚度及次框架对巨型钢框架结构反应、抗震设计方法及抗震性能的影响。本文选取了具有代表性的3个巨型钢框架结构作为算例，假设了4个计算方案，即方案1：仅考虑主框架、不考虑楼板刚度；方案2：考虑主、次框架协同工作、不考虑楼板刚度；方案3：考虑主、次框架协同工作和楼板刚度；方案4：仅考虑主框架和楼板刚度。应用有限元分析软件ANSYS，选取了代表不同场地条件的5条典型地震波，对不同计算方案的3个算例进行三维地震时程反应分析。通过对算例1方案1和方案4及算例1-3方案2和方案3结构周期、位移和内力反应的比较，研究了楼板刚度对巨型钢框架结构反应的影响，得到如下结论：与普通钢框架的梁、柱相比，巨型钢框架中主框架的巨型梁、巨型柱截面尺寸要大得多，并且由它们组成的这种超常规的大型结构具有巨大的抗侧刚度和整体工作性能，因此，在地震作用下，考虑楼板刚度与否对巨型钢框架结构整体反应影响不大，对主框架柱位移和内力反应影响也不大，但对次框架位移和内力反应的影响相对较大。由此可见，我们有理由采用计算方案1代替方案4与方案3比较来研究次框架对巨型钢框架结构反应和抗震性能的影响。通过3个算例方案1和方案3结构周期、位移和内力反应的比较分析可知，次框架可以进一步增加巨型钢框架结构的抗侧刚度，减少结构侧向变形，特别是明显减少了结构最大层间位移，使整个结构的内力与变形分布更为均匀；次框架的加入使主框架柱最大轴力较无次框架情况减少，而主框架柱的最大剪力和弯矩较无次框架情况都有所增加，由此可知，虽然主框架本身可以成为独立的结构体系，但在分析设计时，还应该考虑主、次框架协同工作，进行整体分析、整体设计，否则结构会偏于不安全。通过研究还发现，组成一个巨型柱的内榀柱的剪力和弯矩增加幅度比外榀柱要大得多，设计时也应给予注意。更多还原

【Abstract】 In this paper, the mega structure and its characteristics are introduced. The mechanical models, analysis methods and the present seismic research condition of the structures are summarized. The main problems and the direction of further seismic research of the structures in future are pointed out.On the basis of these, the paper studies profoundly the influence on response, seismic design method and seismic behavior of the mega steel structures from the floor stiffness and hypo-frame. Three representative mega steel-frame structures are selected. Four calculative modes are hypothesized, which are, mode 1: considering the main-frame, not considering the floor stiffness; mode 2: considering the cooperation of main and hypo frames, not considering the floor stiffness; mode 3: considering the cooperation of main and hypo frames, and the floor stiffness; mode 4: considering the main-frame and the floor stiffness. 5 typical earthquake waves are selected, which represent different site conditions respectively. Using finite element program ANSYS, three-dimensional history time analysis of three mega steel-frame structures with different calculative modes subjected to different earthquake ground motions are conducted. The results of structural period, displacement and internal forces including axial force, shear force and bending moment are obtained. In order to study how the floor stiffnesses influence on the mega steel-frame structures, the results of mode 1 and mode 4 of example 1, and those of mode 2 and mode 3 of three examples are compared. Some conclusions are obtained as follows: compared with beams and columns of the common steel-frame structures, the cross-sectional dimension of mega beams and mega columns in the main-frames of mega steel-frame structures are very large. Because the mega structure system has great lateral stiffness and entirety work behavior, whether or not considering the floor stiffness has less influence on the entirety responses of the mega steel-frame structures and on the displacement and internal forces of columns of the mainframe, but larger influence on the response of columns of hypo-frame. So it is reasonable that mode 1 substituting for mode 4 is compared with mode 3 to study the influence on response, and seismic behavior of the mega steel structures from the hypo-frame. Compared the results of structural period, displacement and internal forces of mode 1 with mode 3, we can know that the hypo-frame can increase the lateral stiffness of the mega steel-frame structures, decrease lateral-deformation of the structures, especially decrease the maximum inter-storey displacement obviously, and get the internal forces and deformation of the whole structure more uniform. From the analysis results, it can be found that the maximum axial force gets lesswith hypo-frame than without it, and the maximum shear force and bending moment get more with hypo-frame than without it. Thus it can be seen that the mainframe can be an independent structure system by itself, but the cooperation of main and hypo frame should be considered for conducting the entire analysis and design, otherwise the mega structure can be unsafe, In addition, from the comparing analysis, it can be found that the shear force and bending moment of inside-row columns are increased much more than those of outside-row ones in a mega column. So this phenomenon should be paid attention during designing of a mega structure.更多还原