【作者】 刘凯；

【导师】 张崇厚； 刘彦生；

【作者基本信息】 清华大学 ， 建筑与土木工程（专业学位）， 2019， 硕士

【摘要】 自建筑出现以来,人类就不断追求使其跨越更大空间的可能性,大跨度建筑及大跨度结构技术是一个国家建筑科技水平的重要标志之一。本文以大跨度结构的工程问题为导向,以为结构设计服务为出发点,对大跨度结构的受力机理进行了研究,结合工程实例对索结构的相关问题进行了深入探讨,为结构设计人员从力学原理出发解决大跨度结构尤其是索结构的设计问题提供参考和指导。主要工作和成果如下:1)探讨了大跨度结构的受力效率问题。根据结构抵抗竖向荷载产生的力矩的特点,可以将大跨度结构分为三大类,即梁式结构、桁架式结构和索拱式结构。理论分析和算例分析表明,在抵抗竖向荷载产生的力矩方面,索拱式结构效率最高,桁架式结构次之,梁式结构最低。索拱式结构受力效率的优势可以从构件受力层次、内力外力层次和力臂层次进行直观的解释。2)探讨了索的刚度问题。索结构从材料、构件的连接与约束、构件的几何形状和结构的内力中获得刚度。索的刚度包括侧向刚度和轴向刚度。索的侧向总刚度由小位移线性刚度、几何刚度和大位移刚度构成,理论分析表明,在索变形过程中,三种刚度存在转化关系。索的轴向刚度受索的垂度影响。通过对比索在不同荷载模式下的变形,论证了索的轴向刚度对其侧向变形存在影响,当索承受的荷载模式发生改变时,索的侧向变形会显著增大。3)探讨了索结构设计的关键问题,并结合工程实例进行阐述。分析了索结构在安全性、适用性、经济性方面的特点,探讨了索结构在传力路径、整体冗余度、整体刚度、受压杆件稳定性等方面的设计难点及解决方案。模型建立是索结构计算过程中结构工程师直接面对的难点,参数化建模是应对该难点的有效手段。探讨了参数化建模的原理、流程和优势。4)探讨了索结构设计过程中需要考虑的施工复杂性。考虑施工复杂性是索结构设计工作中极为重要的内容,结合工程实例分析了设计过程中需要着重考虑的施工复杂性因素,以及解决施工复杂性问题的方法。对工程实例中的施工关键问题进行了探讨,指出施工步骤的确定应保证设计意图的实现。更多还原

【Abstract】 Since the advent of architecture,mankind has been pursuing the possibility of making it reach a larger span.Large span buildings and the technology of large span structure are one of the important signs of a national building technology level.This paper is guided by the engineering problem of large span structure,aiming to be helpful for the structure design.The mechanism of the large span structure is studied,and the related problems of the cable structure are discussed based on a project case.This paper may provide reference and guidance for solving the design problems of large span structures,especially cable structures.The main work and results are as follows:1)The efficiency of large span structures is discussed.According to the characteristics of the moment generated by the vertical load,the large span structures can be divided into three categories,namely beam structure,truss structure and cable-arch structure.Theoretical analysis and case analysis show that the cable-arch structure has the highest efficiency in resisting the moment generated by the vertical load,the truss structure is the second,and the beam structure is the lowest.The advantage of the efficiency of the cable-arch structure can be explained intuitively from the component stress level,the internal-external force level and the force arm level.2)The stiffness of the cable is studied.The stiffness of the cable structure is related to the material,the connections and constraints of the components,the geometry of the components,and the internal forces of the structure.The stiffness of the cable includes lateral stiffness and axial stiffness.The lateral stiffness of the cable is composed of small displacement linear stiffness,geometric stiffness and large displacement stiffness.Theoretical analysis shows that there is a transformation relationship between the three kinds of stiffness during the cable deformation process.The axial stiffness of the cable is affected by the sag of the cable.It is demonstrated that the axial stiffness of the cable has an influence on its lateral deformation by comparing the deformation of the cable under different load modes.When the load mode of the cable changes,the lateral deformation of the cable will increase significantly.3)The key issues of cable structure design are discussed based on a project case.The characteristics of cable structure in terms of safety,applicability and economy are analyzed.The design difficulties and solutions of cable structure in terms of the force transmission path,the overall redundancy,the overall stiffness and the stability of the compression bars are discussed.It is difficult for structural engineers to establish the model in the process of cable structure calculation.Parametric modeling is an effective means to deal with this difficulty.The principle,process and advantages of parametric modeling are discussed based on the project case.4)The construction complexity that needs to be considered in the cable structure design process is discussed.It is extremely important to consider the complexity of construction in the design of cable structure.The construction complexity factors are analyzed based on the project case,and the methods to solve the construction complexity problems are proposed.The key construction problems in the project case were discussed,and the conclusion that construction steps should ensure the realization of the design is achieved.更多还原