超高巨柱—核心筒—伸臂结构地震灾变及抗震性能研究

发布时间：2018-10-21 18:46

【摘要】：近年来，我国在地震区修建了大量超高层建筑，使得超高层建筑的抗震性能成为工程界和学术界共同关注的热点。超高巨柱－核心筒－伸臂结构是近年来在超高层建筑中应用较多的一种结构形式。本文以632m的上海中心大厦这一典型的超高巨柱－核心筒－伸臂结构为基本研究对象，对其在特大地震下的动力灾变和抗震性能展开了系列研究，重点研究了其在特大地震下的动力灾变模拟、合理的地震动强度指标的选取、地震耗能分布规律以及最小地震剪力系数对超高巨柱－核心筒－伸臂结构抗震性能的影响等关键问题，取得了如下的主要研究成果：（1）提出了超高巨柱－核心筒－伸臂结构在特大地震下的倒塌灾变过程模拟方法。以上海中心大厦为基本研究对象，利用通用有限元程序MSC.Marc2007建立了合理的有限元模型；并利用基于材料本构层次的生死单元子程序，成功实现了超高巨柱－核心筒－伸臂结构在特大地震下倒塌灾变过程的模拟，为研究其在强震作用下的损伤演化规律和倒塌灾变机理提供了基础。（2）提出了适用于超高层建筑抗震分析用的地震动强度指标。通过对现阶段常用地震动强度指标的分析，结合超高层建筑地震响应中高阶振型影响显著的特点，提出了形式简便的基于弹性反应谱加速度几何平均值的地震动强度指标，并通过大量算例的时程分析，回归得到了指标中关键参数的合理取值，为减小超高层建筑地震响应预测结果的离散性提供了参考。（3）研究了超高巨柱－核心筒－伸臂结构的地震耗能分布规律。通过对上海中心大厦在不同地震动强度下的时程分析，，统计得到了地震耗能分布规律。结果表明：上海中心大厦的地震输入能量主要由结构本身阻尼耗散，塑性滞回耗能则主要集中在结构的上部4个节段，其中伸臂桁架是最主要也是最理想的塑性耗能构件；通过在伸臂桁架上附加粘滞阻尼器，可减轻高阶振型引起的上部节段的损伤程度，使结构侧向变形更加均匀，为超高层建筑的损伤控制提供参考。（4）讨论了最小地震剪力系数对超高巨柱－核心筒－伸臂结构抗震性能的影响。以8度区的假想超高层建筑结构为例，在设计条件完全相同的条件下，按照三种不同的最小地震剪力控制方案设计了三个相应的超高层建筑模型，并基于弹塑性时程分析和倒塌分析，讨论了最小地震剪力系数对超高巨柱－核心筒－伸臂结构抗震性能的影响，为进一步完善超高层建筑设计方法提供了依据。
[Abstract]:In recent years, a large number of super-tall buildings have been built in the earthquake area in China, which makes the seismic performance of super-tall buildings become the focus of common concern in the engineering and academic circles. Super-high column-core tube-arm structure is a kind of structure which is widely used in super-tall buildings in recent years. In this paper, the 632 m Shanghai Central Mansion, a typical super-high column, core tube and cantilever structure, is taken as the basic research object, and its dynamic catastrophe and seismic performance under the earthquake are studied in a series. In this paper, the dynamic disaster simulation and the reasonable selection of earthquake intensity index are studied. The key problems such as the distribution of seismic energy dissipation and the influence of minimum seismic shear coefficient on the seismic behavior of ultra-high giant column-core tube-extension arm structures are discussed. The main research results are as follows: (1) A method for simulating the collapse and catastrophe process of ultra-high giant column-core tube-extended-arm structures under a large earthquake is proposed. Taking Shanghai Central Mansion as the basic research object, the reasonable finite element model is established by using the universal finite element program MSC.Marc2007, and the life and death element subprogram based on the material constitutive hierarchy is used. The collapse and catastrophe process of ultra-high giant column, core tube and extended arm structure under a large earthquake is successfully simulated. It provides a basis for studying the law of damage evolution and collapse mechanism under strong earthquake. (2) the index of ground motion intensity suitable for seismic analysis of super-tall buildings is put forward. Based on the analysis of the commonly used ground motion intensity indexes at present and the remarkable influence of high order modes on the seismic response of super tall buildings, a simple and convenient index of ground motion intensity based on the geometric average of the acceleration of elastic response spectrum is proposed. Through the time history analysis of a large number of examples, the reasonable value of the key parameters in the index is obtained by regression. This paper provides a reference for reducing the dispersion of earthquake response prediction results of super-tall buildings. (3) the distribution of seismic energy dissipation of super-tall column-core tube-arm structures is studied. Based on the time-history analysis of Shanghai Central Mansion under different ground motion intensity, the distribution of earthquake energy dissipation is obtained by statistics. The results show that the seismic input energy of Shanghai Central Mansion is mainly dissipated by the damping of the structure itself, and the plastic hysteretic energy dissipation is mainly concentrated in the upper four segments of the structure, in which the cantilever truss is the most important and ideal plastic energy dissipation member. By attaching viscous dampers to the cantilever truss, the damage degree of the upper segment caused by high-order modes can be reduced, and the lateral deformation of the structure can be more uniform. It provides a reference for damage control of super-tall buildings. (4) the influence of minimum seismic shear coefficient on seismic behavior of super-tall column-core tube-arm structures is discussed. Taking the hypothetical super-tall building structure in the 8 degree region as an example, under the same design conditions, three corresponding super-tall building models are designed according to three different minimum seismic shear control schemes. Based on the elastic-plastic time-history analysis and collapse analysis, the influence of the minimum seismic shear coefficient on the seismic behavior of super-tall column-core tube-arm structures is discussed, which provides a basis for further improving the design method of super-tall buildings.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU973.31

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