【作者】 雷宇；

【导师】 赵雷；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2009， 博士

【摘要】 论文在总结中外学者研究成果和中外设计规范的基础上,结合我国斜拉桥稳定性的研究经验,系统的研究了组合梁斜拉桥施工全过程的稳定性问题。全文在结构和内容上主要分为两个部分:第一部分为组合梁斜拉桥基本理论、混凝土三维徐变理论,包括第1章～第2章,属于理论与方法;第二部分是实现稳定研究而进行的通用有限元软件接口程序开发和组合梁斜拉桥施工全过程整体稳定、局部稳定、稳定关系的计算与研究,包括第3章～第7章,属于应用与研究。论文主要针对以下多个方面的内容展开工作:1)第1章～第2章,主要研究了斜拉桥与钢-混凝土组合梁的发展历史、应用现状、以及存在的关键技术问题,并基于三维粘弹性理论对三维状态下的徐变计算方法做了详细分析与介绍;2)通用有限元计算软件在实现桥梁结构的特殊功能时需要开发专业的接口程序。第3章基于通用有限元软件Abaqus,研究了对斜拉索采用降温法实现目标索力、斜拉索在极限承载力分析过程中实现断裂、梁单元在积分点处施加残余应力的实现方法与过程;施工阶段的状态具有继承性,为了将一种分析的计算结果作为另外一种分析的初始状态,达到计算结果在不同的分析类别之间转换时可以修改材料、增减结构的单元、可以只读取需要的单元结果的目的,开发专业接口程序的方法与过程;3)第4章以具体的工程背景研究了组合梁斜拉桥施工全过程的第一类与第二类整体静力稳定性。参考几座重要桥梁的稳定性研究规律,对斜拉桥施工全过程第一类稳性安全系数与屈曲模态的发展规律进行深入的研究、总结;通过具体的计算实例,研究了不同的施工内容在同一施工梁段内安全系数的变化规律、相同的施工内容在不同梁段内的变化规律;研究不同斜拉索材料对结构整体稳定性的影响;研究了混凝土本构关系对结构第二类整体稳定性的影响;研究结构部件对整体稳定性的影响及其在全过程中的发展规律;针对单主梁与双主梁两种不同的主梁模式,研究两者稳定性的差异与差异的原因;对组合梁斜拉桥稳定性的影响因素,如结构的剪力钉、钢主梁的残余应力、结构的初始状态、单元的安装方式(切线法、零位移法)进行具体的研究,对这些因素的影响程度给予评价;混凝土桥面板具有明显的时变效应,随着时间的变化混凝土要发生徐变,变形受到钢梁的约束,导致组合梁中混凝土桥面板和钢梁的应力重分布,研究了混凝土桥面板的徐变效应对结构稳定性的影响,并对这种影响的程度给予评价;4)第5章以具体的工程背景研究了组合梁斜拉桥施工全过程的第一类与第二类局部静力稳定性问题,主要研究了构件的初始缺陷对于稳定性的影响;研究组合梁斜拉桥施工全过程横梁、锚拉板、桥面板、钢主梁最不利状态下的局部稳定性;5)第6章结合整体稳定性、局部稳定的研究结果得出一些关于施工全过程中整体与局部失稳先后性的结论;采用细化模型(降低单元长度、局部区域精细化)研究整体稳定与局部稳定的相关性;最后,对论文的研究工作进行了总结,指出有待进一步研究的问题,并对此进行了讨论。更多还原

【Abstract】 Based on the research results summarized by Chinese and foreign scholars and the design specifications at home and abroad, the problems of the stability in the whole construction process of the cable-stayed bridge are studied with the research experiences of stability in China. The thesis is divided into two parts depending on structure and content.The first part is from Chapter 2 to Chapter 4 ,the basic theories of cable-stayed bridge with composite beam, stability, and the three-dimensional creep of the concrete are introduced, which is belong to the aspect of theory and method; the second part is from Chapter 5 to Chapter 7, the development of interface program of the general finite element software for the study of Stability is made, the calculation of overall, local stability and interactive stability, the research and summary of the regular pattern are provided, which is belong to the aspect of research and application. The main aspects of work in the paper as follows:1) From chapter 1 to Chapter 4, the historys of the cable-stayed bridge and steel - concrete composite beam, application status, the key technical issues, and basic theorys of composite beam cable-stayed bridge are mainly introduced, the main reasons of the stability of cable-stayed bridge, the classification of stability, the main research content and research methods of stability are discussioned; the problems of three-dimensional creep in concrete are studied, and the computation method of concret creep under the state of three-dimensional are analyzied particularly and introduced in detail depend on the theory of three-dimensional viscoelastic theory.2) In order to achieve the special function of bridge structure, the general finite element analysis software need to develop a professional interface program, In chapter 5, the method and process are researched as following: achieving target forces of tendons using cooling method in Abaqus; achieving failure of stayed cable in the ultimate bearing capacity analysis process; and exerting Residual Stress through integration points in the element of beam; Moreover, because of the inheritance existed in the status of construction, the method and process of developing the professional interface procedure are researched to make the former result as the initial state of the latter analysis, then materials and element amouts can be changed when changing the results in the different categories of analysis.3) The main content of the chapter 6 is the discussion of first and second category of overall static stability of cable-stayed bridge in the whole construction process with the view of the engineering background. The law of safety factor and buckling mode in the first category stability in the whole construction process are studied and summarized by referencing the stability regular of several important bridges; according to the concrete examples of calculation, the laws of variety of the safety factor of different construction content in the same state and the same content in different Beam Segment are studied; After compairing the affect produced by changing different stayed cable material, some conclusions are obtained; the impact produced by concrete constitutive relation on the second category overall stability are researched; how to impact the second category overall stability and the law through the whole construction process are put forward; the stability calculation results of the two different models (single -Main beam and double-girder of the main beam) are compared and the reasons causing the difference are discussioned; Discussion and evaluation are made regarding the impact degree of some Influencing Factors Such as Shear Studs, Residual Stress of the main beam, Initial State of the structure, installation method of the element (tangent method, zero-displacement method); Concrete Slab possess time-dependent effect, creep will take place as time goes on,but because of the transformation constrainted by steel beam, stress redistribution of Concrete Slab and steel beam is produced, thus, the influence of stability caused by Creep Effect are studied and evaluated.4) In Chapter 7, based on the specific engineering background, the problems of the first category and second category of local static stability through the whole construction process are researched, it is mainly studied the effect on the stability produced by initial imperfection of structure; The Local Stability under the most dangerous state of cross beam , tensile anchor plate, Bridge Deck, and steel girder are researched.5) In chapter 8, combing the results of global stability and local stability, the sequence of the whole stability and partial stability in the whole construction process are conclused; the relativity of the whole stability and partial stability when reducing the element length and considering the stress complex region is researched by establishing refined model.Finally, summarize the research work on this paper, and point out the issues which be studied further, carry on the discussion for this.更多还原