【作者】 苏原；

【导师】 陈传尧； 李黎；

【作者基本信息】 华中科技大学 ， 结构工程， 2009， 博士

【摘要】 框架-筒体结构中的外框架属一般框架，能够给予建筑创作较多的选择和自由，因此，框架-筒体结构在高层建筑中得到了广泛应用；为了克服框架-筒体结构存在的侧向刚度较小的弱点，工程中通过采取在框架-筒体结构中设置刚度很大的结构加强层的措施，形成了带加强层框架-筒体结构。目前对于带加强层框架-筒体结构的研究一般多为针对个例进行定性分析，或采用忽略某些构件作用，比较简化的力学模型进行定量研究，这种定性分析或定量研究对结构体系的力学性能的认识尚不够全面、准确。对结构力学性能认识的模糊，会使得在结构设计中合理选择结构体系、确定和调整结构方案等方面遇到困难。本文在同时考虑筒体、伸臂、楼面梁和外围框架等对带加强层框架-筒体结构力学性能有重要影响的结构构件、基于弹性、小变形和结构构件几何参数沿高度连续不变的基础上，建立了一个全新的结构计算模型，对带加强层框架-筒体结构体系做了较为全面、系统的分析研究。本文主要完成了以下工作：首先，根据带加强层框架-筒体结构体系的特点，在框架-剪力墙结构连续化分析的计算简图中加入水平伸臂和楼面梁，形成了顶部带加强层框架-筒体结构的结构计算模型。根据高层建筑结构连续化分析方法、势能驻值原理和泛函变分方法，推导出了顶部带加强层的框架-筒体结构侧移计算公式；通过引入相对坐标、框-筒刚度特征值和伸臂刚度特征值，得到了带加强层的框架-筒体结构在倒三角形荷载、均布荷载、顶部集中荷载和顶部集中弯矩作用下的侧移计算式、以显式表达的解析解和结构构件的内力计算式。通过对本文结构侧移计算方法的退化验证以及与有限元计算结果的对比分析，表明了本文方法的可信性。其次，研究了框-筒刚度特征值和伸臂刚度特征值在各种水平荷载下对顶部带加强层框架-筒体结构侧移和筒体弯矩的影响，通过分析各种结构构件几何尺寸的变化对刚度特征值的影响，得出了各种结构构件对顶部带加强层框架-筒体结构侧移和筒体弯矩的影响规律。第三，对带加强层框架-筒体结构适用范围、水平伸臂“最佳刚度”和加强层的“最佳位置”等问题进行了研究，得出了定量分析结果。在讨论加强层的“最佳位置”时，研究了单道加强层和两道加强层位置与筒体弯矩突变量之间的关系。第四，关于筒体剪力突变问题，本文研究结果表明影响筒体墙肢剪力突变的主要因素是伸臂弯矩(也就是筒体在加强层处的弯矩突变量)和伸臂高度，同时给出了减少该类结构内力突变的措施，提出了水平伸臂采用小截面面积、大截面高度的设计理念，为同类结构减少内力突变量、减少结构薄弱层的影响提出可供参考的方法。第五，对于周边环带进行了分析。结果表明在设置水平伸臂后加设周边环带，可以有效地降低外围框架翼缘柱轴力不均匀的程度，使得各柱轴力趋于均匀；可以使伸臂和环带的内力大幅降低，改善加强层楼板的受力状态，增加整个加强层的整体性。总之，本文研究表明，影响带加强层框架-筒体结构力学性能的主要因素是：框-筒刚度特征值λ、伸臂刚度特征值γ和加强层位置，它们三者的关系，决定了带加强层框架-筒体结构的力学性能；周边环带在与水平伸臂设置在同一层时，环带主要起增加加强层的刚度和整体性，保证结构整体性的作用。更多还原

【Abstract】 The frame - core structure has an extensive application in high-rise buildings. The external frame in the frame-core structure is the average frame, which can be made a number of choices in architectural innovation. In practical engineer, outriggers with large stiffness are adopted to avoid the effects of small lateral stiffness in the frame - core structure. Thus, the frame - core structure with strengthened story is formed.In the literature, the research on the frame - core structure with strengthened story focused on either the personal case or the comparison of simplified mechanical model by ignoring the action of certain components. However, the previous study is not full-scale and accurate on the mechanical capacity of the stuctural system, which will encourter the difficulty on aspects of choice structural system as well as determination and modification of structural scheme in sturctural design. Considering the effects of core, outriggers, floor beam and perimeter frame, a new sturctural computing model is established base on linear, small deformation and gemetrical parameters of structural components being continuons and constant over the vertical direction. A comprehensive analysis is done for the frame -core structure with strengthened story in the thesis.The primary work in the thesis is as following:First of all, in accordance with the characteristic of the frame - core structure with strengthened story, adding the outriggers and floor beams into the computing diagram of continuity analysis for frame-shear wall sturcture, the structural computing model is formed with the outrigger at the top in the frame-core sturcture. The formulas of the lateral displacement for the top outrigger braced frame - core structure are derived base on the principle of minimum potential energy, functional variation method and continuum approach for tall structures. According to the introduction of relative coordinates, frame stiffness characteristic parameter and stiffness characteristic parameter of outriggers, terse format analytic expressions for structure lateral displacement and internal force calculation under lateral distributed load, top concentrated load and top moment are obtained. With the retrogressed verification for the lateral displacement computing method and the comparison with finite element method, the results indicate the reliability of the method.Secondly, the influence of the frame stiffness characteristic parameter and stiffness characteristic parameter of outriggers on the structure lateral deflection and core moment under lateral distributed load, top concentrated load and top moment are analyzed. According to analyzing the effects of geometrical parameters of structural components on the characteristic value of stiffness, the impacts of the structural components on structure lateral deflection and core moment are obtained.Thirdly, the research focuses on the applicable range for frame-core structure with strengthened story, the optimal location and rigidity of outriggers. In particular, for the optimal location of strengthened story, the relationship between single and two strengthened story position and the core moment reversal is analyzed.Fourthly, the results show that the key factors for the impact of core shear force reversal are outriggers’ moment, that is the reversal amount of core moment at the location of strengthened story, and outriggers’ section depth. The method to reduce the internal force reversal are given. The design conception to adapt small sectional area and large section depth with outriggers is which can reduce the reversal amount of internal force and structural weakness story for analogous structure.Finally, the belt is analyzed. The results show that setting belt after setting outriggers can effectively reduce uneven degree of axial forces of the external frame columns. It can also dramatically reduce internal forces of outriggers and belt, improve the stress and strain states of the floor of the strengthened story, and increase the integrity of whole strengthened story.To sum, this thesis indicates that the key factors to effect the mechanical property of the frame-core structure with strengthened story are the frame stiffness characteristic parameter, the stiffness characteristic parameter of outriggers and the location of strengthened story. The relatiship among them determines the mechanical property of the frame-core structure with strengthened story. When belt and outrigger are set at the same story, the belt can improve the stiffness of the strengthened story and ensure the integrity of the structural.更多还原