大跨度钢结构施工力学分析及应用研究

发布时间：2018-01-28 06:54

本文关键词： 大跨度钢结构施工力学 “生死”子结构预夹角找形优化　出处：《华南理工大学》2011年博士论文　论文类型：学位论文

【摘要】：施工力学在大跨度钢结构工程中的应用已经是当今工程界和学术界的热点课题,该方面研究工作需要对作为其力学基础的时变力学有清楚的认识和理解。本文在前人工作的基础上,针对工程界亟待解决的大跨度钢结构施工相关问题,结合现场监测数据,运用施工力学方法进行了研究,取得了一定的效果。主要工作如下: 1.对施工力学的研究特点及分类进行了分析,完善了土木工程施工力学研究的课题以及施工力学效应。作为研究对象的施工力学理论基础,重点讨论了时变力学主要研究内容以及施工力学基本方法和特点,给出了相应问题的时变力学基本方程和有限元算式。 2.讨论了大跨度钢结构施工力学数值分析方法、特点和参数时变的意义,针对施工过程中结构几何及边界条件随时间不断变化这一施工力学分析难点,基于结构分段安装以及先装和后装可通过节点构造预夹角的概念,提出“生死”子结构先后独立求解,调整“死”结构边界节点转动约束条件的施工模拟方法,推导了“生死”子结构的有限元方程。通过典型算例验证方法的有效性及先进性,并进行了实际工程分析。 3.基于深圳会展中心工程施工和使用期钢结构的应力和变形现场实测数据,结合结构主梁、下弦钢棒以及边界约束条件时变的特点,进行了全过程“生死单元法”及本文方法的模拟计算和分析。考虑几何非线性以及胎架的支撑与落架,模拟了多种载荷条件下构件受力和变形,比较分析了三种数据及变化规律;同时进行了拆撑过程路径相关性分析和探讨,得出了一些有益结论,供设计和施工者借鉴。 4.张弦梁找形分析属于施工力学逆解问题,讨论了考虑大变形情况下应用温降法和初应变法模拟施加预应力时单元刚度和应力产生偏差的问题,提出了相应应力和刚度的修正方法;借鉴机械结构螺栓预紧力的概念,给出了模拟张弦梁预张拉的有效方法并克服了上述方法的弱点,通过典型算例验证了方法的有效性。 5.鉴于张弦梁张拉过程撑杆转动对结构体系受力和变形影响大,选择张拉前后撑杆转动量极小化为优化目标,提出了线性预测-非线性校正的优化方法。算例分析了方法的有效性,同时发现三种拉拔预张拉方式中,从中间跨通过花篮螺栓预张拉相对较好的优化结果,对于结构设计和施工具有一定的实际意义。
[Abstract]:The application of construction mechanics in large-span steel structure engineering has become a hot topic in engineering and academic circles. This research work needs to have a clear understanding of time-varying mechanics as the basis of its mechanics. Based on the previous work, this paper aims at the problems related to the construction of long-span steel structures that need to be solved urgently in the engineering field. Combined with the field monitoring data, using the method of construction mechanics to carry on the research, has obtained the certain effect. The main work is as follows: 1. The research characteristics and classification of construction mechanics are analyzed, and the research subject of civil engineering construction mechanics and the effect of construction mechanics are improved, which is the theoretical basis of construction mechanics as the object of study. The main research contents of time-varying mechanics and the basic methods and characteristics of construction mechanics are discussed emphatically. The basic equations of time-varying mechanics and the finite element formulas for the corresponding problems are given. 2. The numerical analysis method of construction mechanics of long span steel structure, its characteristics and the significance of time-varying parameters are discussed. In view of the difficult point of construction mechanics analysis, the geometry and boundary conditions of the structure are constantly changing with time during the construction process. Based on the concept of segmented installation of structure and pre-angle construction of nodes, a construction simulation method of "life and death" substructure is put forward, which adjusts the rotational constraint condition of boundary node of "dead" structure. The finite element equation of "life and death" substructure is derived. The validity and advanced nature of the method are verified by typical examples, and the practical engineering analysis is carried out. 3. Based on the field measured data of stress and deformation of steel structure in construction and service life of Shenzhen Convention and Exhibition Center, combined with the time-varying characteristics of main beam, lower chord steel bar and boundary constraint conditions. The whole process of "birth and death element method" and the method in this paper are simulated and analyzed. Considering the geometric nonlinearity and the support and falling frame of the tire frame, the force and deformation of the member under various load conditions are simulated. Three kinds of data and their changing laws are compared and analyzed. At the same time, the correlation analysis and discussion of the path in the process of brace removal are carried out, and some useful conclusions are obtained, which can be used for reference by designers and constructors. 4. The form-finding analysis of beam string belongs to the inverse solution of construction mechanics. The problem of element stiffness and stress deviation when prestressing is simulated by temperature drop method and initial strain method considering large deformation is discussed. The corresponding stress and stiffness correction method is put forward. Based on the concept of pretension force of bolt in mechanical structure, an effective method for simulating the pretension of beam string is given and the weakness of the above method is overcome. The validity of the method is verified by a typical example. 5. In view of the great influence of the strut rotation on the stress and deformation of the structure system during the tensioning process, the optimum objective is to select the minimum rotation of the strut before and after the tensioning. An optimization method of linear prediction-nonlinear correction is proposed. The effectiveness of the method is analyzed by an example. At the same time, three kinds of drawing pretension methods are found to be relatively good from the middle span through the basket bolt pretension. It has certain practical significance for structural design and construction.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2011
【分类号】：TU391

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