【作者】 姜军；

【导师】 蒲黔辉；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2013， 博士

【摘要】 早期桥梁多是简单的梁、柱、拱、索之类桥式体系,受力明确、造型清晰。但随着科学技术的发展,生产力水平空前提高,桥梁的发展无论从跨越能力提高的速度、结构形式的组合化趋势,还是各种新型材料的应用和合理配置等多方面都有了充分的展现。连续刚构拱组合体系桥充分利用了梁、拱各自桥式的受力优势,优化了结构的受力,节省了工程量,创新了桥梁的外观,是大型公路、铁路桥梁中值得应用与研究的桥式结构。目前有关于连续刚构拱组合桥梁的文献尚不多见,也没有相关文献对其梁拱墩结合部受力行为和锚固区局部应力作过系统深入的分析研究。鉴于以上情况,以宜昌长江大桥为研究背景,系统地开展了大跨度连续刚构拱组合桥结合部受力行为与锚固区局部应力的专项研究。内容主要包括五个部分：1、在收集国内外相关资料和深入分析国内外研究成果的基础上,对大跨度连续刚构拱组合桥的发展与受力特点进行了初步分析,并讨论了其在受力行为研究中存在的问题。以宜万铁路宜昌-万州段新建工程宜昌长江大桥为工程背景,提出了进行大跨度连续刚构拱组合桥结合部受力行为与锚固区局部应力研究的课题。2、提出了大跨度连续刚构拱组合桥名义刚度的概念,分析了结构参数对名义刚度的影响,推导出名义刚度理论公式。针对拱梁刚度比的选取及其对结构内力分配的影响进行讨论,分析其对结构内力的影响规律,并得出刚拱柔梁与柔拱刚梁的界定值,为设计人员选取构造参数提供指导。3、基于结构试验模型相似理论,进行静力相似原则的分析和推导,确定模型的相似比,采用模型的基本设计原则,设计并完成了边主墩和中主墩梁拱墩结合块模型试验。同时对模型的材料特性进行力学性能测试,给数值分析提供正确的材料参数。通过计算分析确定加载工况,在切实可行的加载方法下,制定加载程序。最后确定测试内容、方法和测点布置方案。4、介绍了空间静力分析理论,在选定混凝上、钢筋和钢绞线单元的基础上,结合已有的研究成果,建立了梁拱墩结合块三维有限元分析模型,得到数值分析结果,将数值计算结果与试验结果进行对比分析,得出了顶底板、腹板、拱脚和墩顶混凝土应力分布规律,深入研究了梁拱墩结合块的复杂受力行为。5、建立了锚下混凝上局部承压的基本理论,包括对局部受压区的应力状态、局部受压的破坏特征、锚下混凝上局部承压的剪切破坏机理以及局部受压承载力的分析研究,然后对顶底板锚下混凝土应力分布情况进行数值分析。结合宜昌长江大桥的设计,对锚固区局部应力进行了模型试验研究。通过对混凝土应力测试结果的研究以及与数值计算结果的对比分析,得出了锚固区局部应力传递规律,归纳出锚固区裂缝产生的原因,为设计提供依据,对同类型的桥梁设计有一定的参考价值。更多还原

【Abstract】 Most of the bridges in early stage are simple bridge systems of beam, column, arch, cable, etc. The characteristics of this kind of bridge are stressing definitely and clearly modeled. However, as the development of technology and the unprecedented improvement of productivity level, the bridges have fully developed in the speed of span ability improvement, the trend of structure form combination and the application and rational allocation of diversity updated materials. It is worthy applying and researching continuous rigid frame composite arch bridge in large highway and railway bridges because it makes full use of each superiority of beam and arch, optimizes structural force bearing conditions, saves engineering quantity, and innovates the appearance of bridges. At present, there are still few documents in continuous rigid frame composite arch bridge and it is not found any relative documents doing systematic research in the mechanical behaviors of beam, arch and pier combination area and local stress distribution in anchorage zones of the bridges. Considering the situations mentioned above, based on Yi Chang Yangtze River Bridge, the author carries out systematic researches on the mechanical behaviors of combination area and local stress distribution in anchorage zones for long-span continuous rigid frame composite arch bridge. The dissertation includes five parts mainly:1. Based on collecting and learning correlative knowledge at home and abroad, the author preliminarily analyzes the development and mechanical characteristics of long-span continuous rigid frame composite arch bridge. The existing problems in the research of mechanical behavior are discussed. Researched on Yi-Wan Railway Yichang-Wanzhou segment newly built engineering Yi Chang Yangtze River Bridge, the author proposes the subject of mechanical behaviors of combination area and local stress distribution in anchorage zones for long-span continuous rigid frame composite arch bridge.2. The author proposes the definition of nominal rigidity of long-span continuous rigid frame composite arch bridge, analyzes the effects of structural parameters on nominal rigidity and derives the theoretical equation of nominal rigidity. The author also discusses the selection of the rigidity ratio of arch and beam and the effect of the ratio on the structure internal forces distribution, and analyzes the influence law of the ratio on the structure internal forces. Then the author gets the delimitation value between rigid arch-flexible beam and flexible arch-rigid beam. It provides a guidance of selecting the structural parameters to designers.3. Based on the similitude theory of structural test models, the author analyzes and derives the static similitude principle, determines similitude ratio of the model, completes the beam,arch and pier combination area model tests in side span and middle span by adopting basic design principle of the model. And the author tests the mechanical properties of the model materials, provides correct material parameters to the numerical analysis. Loading cases are determined by calculation analysis, loading programs are established under feasible loading method. At last, the author determines the testing contents, methods and arrangement scheme of the measuring points.4. The author introduces the space static analysis theory. Based on choosing the constitutive relationships of concrete, steel and strand, the3-D finite element analysis model of beam, arch and pier combination area is established by the combination of existing study results. The numerical analysis results are obtained. Comparing the results of the model tests with the theoretical ones, the stress distribution of concrete in roof, floor, web, arch foot and pier top are obtained. The complicated mechanical behaviors of beam, arch and pier combination area are further studied.5. The author establishes the basic theory of local concrete compression under anchorage zones, including the analysis and research of stress state in local compression area, failure characteristics of local compression, shearing failure mechanism of local concrete compression under anchorage zones, and also local bearing capacity. Then the numerical analysis of the stress distribution in roof and floor anchorage zones are performed. Based on the design of Yi Chang Yangtze River Bridge, the local stress distribution in anchorage zones are studied on model test. By analyzing the stress tesing results of concrete and comparing the results with the theoretical ones, the local stress transferring rules in anchorage zones are obtained, and the causes of cracking in anchorage zones are concluded. These provide evidence for design and have a reference value to develop the same kind of bridge design system.更多还原