【作者】 李波；

【导师】 杨庆山；

【作者基本信息】 北京交通大学 ， 结构工程， 2008， 博士

【摘要】 张力结构通过施工中施加预应力使结构成形后才具有刚度,其施工过程分析与结构设计紧密相连且必不可少。目前对于索穹顶等索杆张力结构的施工分析研究较多且取得许多成果,但对索网结构和膜结构的施工分析研究较少,尤其是膜结构的特殊性使其施工分析难度较大,导致膜结构的施工模拟分析问题尚未得到解决。膜结构是一种对误差较为敏感的空间结构,其支承体系不同的位移偏差会导致上部的索膜出现不同的误差情况,而目前国内外学者在该方面的研究成果还较为缺乏。本文对索网结构和膜结构的施工模拟分析及误差分析进行了深入研究。本文首先系统分析了张力结构尤其是索膜结构施工的特点和施工分析的必要性及难点,在总结了张力结构施工分析和膜结构相关研究现状的基础上,分析了现有张力结构施工模拟计算方法无法直接应用于膜结构的原因。作为施工分析的理论基础,本文采用三节点三角形平面膜单元和两节点直线索单元推导了索网结构和膜结构的几何方程、物理方程和平衡方程。同时研究了现时构形和初始构形上的两种应力和应变的定义及其关系。本文采用逆分析方法对索网结构的施工过程进行跟踪计算,得出施工张拉值与结构在施工各阶段的内力和位移,解决了索网结构常用的分阶段分批张拉并多次调整的施工方法费时费力的问题。对不同施工张拉顺序进行了分析比较,并针对工程实例应用本文方法与常规方法进行了对比分析。本文对已有的褶皱判断和处理的方法进行分析比较后,采用主应力一主应变准则来判断施工中褶皱的出现,并对修正本构矩阵方法进行改进以处理膜结构施工过程中褶皱或松弛的单元。提出了逆分析和正分析相结合的方法对膜结构的施工过程进行模拟计算,在膜结构分析软件CAFA1.0基础上编制了索膜结构施工分析程序,对马鞍形曲面和圆锥形膜结构分别进行了施工分析,得出施工初始态、施工张拉控制值和施工过程中结构的内力、位移、反力等参数,详细讨论了不同的施工顺序对施工过程的影响,并对考虑支承与否的马鞍形索膜结构的施工过程进行了对比分析。对威海市体育场看台挑蓬这一大型张拉膜结构进行了施工过程分析,得出各单体张拉时的相互影响情况。与原施工张拉方法相比,本文方法按计算出的施工张拉值施工,不需反复多次调整张力,可提高工作效率降低施工成本。对膜结构下部支承点不同方向不同组合的尺寸偏差引起上部的索膜中应力、位移和支座反力等参数的不同误差情况进行了分析计算,得出最不利的情况。讨论了现行膜结构技术规程中施工验收的相关规定及存在的问题,并探讨了规程对膜的下部支承结构的误差规定需要细化的问题。使用本文的方法可对施工误差进行定性和定量分析,为规程的施工验收规定提供依据。更多还原

【Abstract】 Construction analysis is necessary for tensile structures which are different from normal structures. In recent years, some results on it have been obtained about tensile structures such as cable dome. But construction analysis about Cable Nets and Membrane Structure has not been solved for their special performance. Being sensitive for inaccuracy, different errors of supporting structure cause different errors of membrane. Few results have been obtained about error analysis of Membrane Structure. Construction analysis and error analysis are researched in this dissertation.The necessities and present research of Membrane Structure construction analysis are studied. Reasons are discussed which tensile structure’s construction analysis method can not be suitable for Membrane Structure.Geometric equation, physics equation and balance equation of Cable Nets and Membrane Structure are developed with nonlinear finite element method about membrane and cable elements. Two stresses and strains in the original and updated reference configurations are studied.The inverse process analysis method is proposed which can simulate Cable Nets construction procedure. Through the method, the tensile force and deformation in the course of construction can be obtained. At the same time, traditional tension method is improved. Construction processes with different tension order are studied. The method in this paper and the traditional construction method are compared through some actual projects.Three states of Membrane Structure in construction process are divided in this paper, which are original state, construction state and designed state. Construction original state is proposed to be convenient for construction analysis. Criteria for the wrinkling judgment and approaches for wrinkling analysis are studied. The principal stress and strain criterion, the modified constitutive relationship method are appropriate for Membrane Structure construction analysis about wrinkling.The method which combines inverse and direct process analysis is proposed to study the construction course of Membrane Structure. And it is programmed for full process of construction simulation. Through the program, saddle and cone Membrane Structures stress, displacement, reaction and tensile force in the course of construction can be obtained. The influence of different tension order and support on construction process is researched. Weihai stadium, a large-scale Membrane Structure, is analyzed on its construction process. The interrelationship regularity in tension process is obtained.The stress or displacement error which is induced by different dimensional discrepancy of the support is calculated. Some problems of technical specification for membrane structures, such as the error range need to be specified more detailed, are discussed. And the error analysis result can be reference for technical code for work and acceptance更多还原