【作者】 丁幼亮；

【导师】 李爱群；

【作者基本信息】 东南大学 ， 防灾减灾工程及防护工程， 2004， 硕士

【摘要】 近年来,在高层建筑顶部安装钢结构塔楼的建筑结构体系应用日益增多。但是历次地震震害表明,地震作用下屋顶上的塔楼地震反应强烈,即使在主体结构无震害或震害很轻的情况下,屋顶塔楼也会发生严重破坏。目前这种结构体系的抗震设计方法国内研究得较少,更缺乏系统性的研究,以致工程设计上缺乏较为合理的实用设计方法。本文对带钢塔楼高层建筑结构体系的抗震设计方法进行了较为系统的研究,较为深入地研究了动力特性、阻尼计算模型、地震作用计算方法和抗震设计方法。以江苏省电网调度中心为例,采用三维空间有限元模型研究顶部安装钢结构塔楼的高层建筑动力特性。从整体动力特性可以看出,当高层建筑在地震动作用下产生振动时,屋顶钢塔在高层建筑屋顶层振动的激励下,产生二次型振动,发生显著的“鞭梢效应”。根据Rayleigh-Ritz法的基本原理,本文给出了带钢塔楼高层建筑动力特性的简化近似计算方法。对于这种主体结构和钢塔组成的组合体系,可以分别求出钢塔和主体结构各自的周期和振型,采用Rayleigh-Ritz法将其进行组合近似求解整体动力特性。讨论了结构动力分析中阻尼计算模型的研究进展,在此基础上研究了非比例阻尼结构体系的动力响应特点。从工程实际应用出发,研究了带钢塔楼的钢筋混凝土高层建筑结构体系等效粘滞阻尼比的计算方法,并采用等效粘滞阻尼比来考虑钢塔楼和主体结构不同阻尼耗能特性的影响。分析表明,带钢塔楼的钢筋混凝土高层建筑进行地震响应计算时,钢塔楼内力标准值需要根据结构的等效粘滞阻尼比进行调整,其余的结构地震响应可不作调整。在总结带钢塔楼高层建筑整体地震作用的计算方法的基础上,采用基于振型分解的结构地震响应时程分析方法分析高阶振型在塔楼地震响应中的贡献,提出了采用振型分解反应谱法和振型分解直接动力分析法时所适宜考虑的振型阶数。本文分析了高层建筑顶部塔楼鞭梢效应产生的本质原因,指出塔楼的鞭梢效应实质上是由于在地震作用下整体结构发生共振产生的,而与塔楼和主体结构自振周期的比值没有直接的联系,并提出了高层建筑顶部塔楼抗震概念设计的基本原则。研究了钢塔楼地震作用的影响因素以及钢塔楼对主体结构地震响应的影响,分别分析了阻尼特性、场地类别、设计地震分组、主体结构质量和刚度、塔楼质量和刚度等因素对塔楼地震作用和主体结构地震作用的影响,在此基础上分别给出了塔楼地震作用和考虑钢塔楼作用的主体结构地震作用的简化计算方法。工程实例计算验证了所提出的简化计算方法的正确性和适用性。总结了带钢塔楼高层建筑的抗震设计方法,并以江苏省电网调度中心为例,采用三维空间有限元程序进行了塔楼与主体结构连接处的局部应力分析。更多还原

【Abstract】 The structural system of steel tower built atop high-rise building has been applied in the practical engineering to a great extent. However, earthquake experiences reveal that the steel tower built atop building will have strong reaction under earthquake action even if the main structure have no or little damage. Nowadays the seismic design method of this structural system has no systematic research so that there is no practical design method for engineering design. The systematic research is applied to seismic design method of structural system of steel tower built atop high-rise building in this paper with respect to structural dynamic property, damping model, earthquake action calculation and seismic design method. The dynamic property of structural system of steel tower built atop high-rise building is studied by three-dimensional spatial finite element model in the case of Jiangsu Electricity-net Dispatcher Center. With respect to integral dynamic properties the steel tower will have secondary vibration under the vibrational stimulation of high-rise building under earthquake to have remarkable whiplash effect. According to the Rayleigh-Ritz principle, the simplified calculation method of dynamic properties of such structural system is presented. For such structural system composed of the main structure and steel tower, the integral dynamic properties can be solved approximately by Rayleigh-Ritz method with the natural period and vibration mode of the main structure and steel tower respectively. The research progress on damping model in structural dynamic analysis is discussed in detail, on the basis of which the characteristics of dynamic responses of non-classical damping structural system are studied. In the view of engineering practical application, the calculation method of equivalent viscous damping ratio of structural system of steel tower built atop high-rise RC building is studied to reflect the various energy dissipation properties of steel tower and the main structure. The analysis results reveal that the internal forces of steel tower need to be adjusted according to equivalent viscous damping ratio in the calculation of earthquake responses of such structural system. On the basis of summarization of calculation methods of structural earthquake action, the contributions of high-order vibration mode to seismic response of steel tower are studied using the direct dynamic analysis method based on the mode-superposition. The principle of choosing vibration mode orders is presented with respect to the response spectrum method and the direct dynamic analysis method based on the mode-superposition.The whiplash effect of the tower built atop high-rise building under earthquake is discussed. The reason of the tower’s whiplash effect is analyzed, which reveals that the whiplash effect will occur due to the co-vibration of the whole structure under earthquake and will not be strengthened when the vibration period of the tower equals to that of the main building. The basic principles of the tower’s seismic conceptional design are presented. The influencing factors to earthquake action of steel tower and the influence of the seismic response of the main structure due to steel tower are studied with respect to damping property, field classification, design earthquake classification, mass and stiffness of the main structure and steel towers, on the basis of which the simplified calculation method of earthquake actions of steel tower and the main structure taken the steel tower into consideration are presented. The computation results of the engineering example reveal the validity and applicability of the simplified calculation method. <WP=7>The seismic design method of structural system of steel tower built atop high-rise building is summarized. The finite element analysis of the joint between the steel tower and the main structure is performed by three-dimensional spatial nonlinear finite element program.更多还原