【作者】 江俐敏；

【导师】 张开鹏；

【作者基本信息】 武汉理工大学 ， 桥梁与隧道工程， 2011， 硕士

【摘要】 近二十年来,随着经济的迅速发展,大跨度桥梁不断涌现,混凝土结构由于其自重大、易开裂、需要的模板支架费用高等缺点,在大跨度桥梁中的应用受到制约。钢管混凝土结构充分结合了钢材抗拉性能好和混凝土抗压性能好的特点,具有承载力高、塑性和韧性佳、耐火性能好、抗震性能好、施工简便、经济效果好等诸多优点,适合应用于大跨度结构。而钢管混凝土空间桁架结构是对传统的箱梁进行不断优化而产生的一种新型结构形式,这种结构形式既利用了钢管混凝土这一轻质高强材料,同时又具有箱梁的优点,并且克服了箱梁的诸多缺点,是大跨度桥梁中比较常用的一种结构形式。由于这种结构形式新颖,受力复杂,目前国内还没有统一的设计、施工规范,故各种设计、施工还处在探索阶段,尚需进一步的完善和优化,以便形成统一的规范。本文以四川境内某钢管混凝土空间桁架梁桥为工程背景,在已有的国内外研究的基础上,对钢管混凝土空间桁架组合梁式桥的设计和施工做进一步的优化。论文的主要研究内容如下：(1)运用有限元程序ANSYS针对下弦管内混凝土不同的浇筑长度建立四个模型,分析它们在静力荷载作用下不同的混凝土浇筑长度对结构位移和局部应力分布的影响,其中的静力作用包括结构仅在重力作用、成桥后桥面板满布均布荷载及左、右幅最外侧车道跨中分别作用偏心荷载四种情形；通过屈曲计算,分析结构的整体稳定和局部稳定；通过模拟其在竖向地震作用下的响应,分析结构的最大位移和最大应力；最后综合对比分析,得出优化后的混凝土浇筑长度为：下弦管内混凝土的浇筑长度为三分之一跨度；(2)对已得出的优化模型,运用ANSYS生死单元高级分析技术,模拟上、下弦管管内混凝土及桥面板混凝土不同的浇筑次序,考虑八种施工工况,通过比较分析结构的位移和局部应力,得出最优的混凝土浇筑次序：先浇筑下弦管内混凝土,再浇筑上弦管内混凝土,桥面板混凝土先浇筑支座段(二分之一跨度),然后浇筑跨中段(二分之一跨度)；(3)通过上述分析计算,对该工程的施工提供指导性意见,并为其他类似结构形式桥型的设计和施工提供参考。更多还原

【Abstract】 With the fast development of economic in recent two decades, long-span bridges spring up, the concrete structure’s application is restricted in long-span bridges because of its big weight,easy to crack, and need higher-cost formwork supports. Concrete filled steel tube structure is characteristic of good bearing capacity, good ductility and toughness, anti-seismic capability and easy construction which fully combines steel’s tensile performance and concrete’s compressive performance characteristics. Spatial truss structure of concrete filled steel tube is a new structure type and been commonly used for bridge which is progress from traditional box girders bridges, and possess both the light weight high strength material-concrete filled steel tube-and most advantages of box girders, furthermore get rid of the disadvantage. However, this brand new structural form’s force-analysis is complex so there is no unified design construction standard, design and construction works are been exploring, problems should be proving and optimizing so as to form a unified standard.In this paper, taking a Space truss girder bridge concrete filled steel tube in Sichuan province for the engineering background, based on domestic and external researches, optimize the design and construction of Spatial truss structure of concrete filled steel tube. The main research contents of paper are as follows:(1) Build four models with deferent pouring length of concrete in lower tube by ANSYS, and analyses the impact of concrete pouring length act on the structural displacement and local stress distribution under static loading, witch including four cases:only gravity, distributed load fully loaded bridge deck, and eccentric load loaded on the lateral lanes of the left half bridge or the right. Analysis the overall stability and local stability of structure by buckling calculation, analysis the maximum displacement and the greatest stress of structure. Through comprehensive contrast, optimal concrete pouring length in lower tube is 1/3 span.(2)Using birth-death element analysis technology in the optimal ANSYS model above, simulate eight different pouring sequences of lower tube, upside tube and bridge deck, by comparing structural displacements and local stresses of eight deferent construction conditions, it can work out the optimal pouring sequence:firstly concrete in lower tube, then higher, secondly concrete of bridge deck in the bearing span -1/2 span-and then mid-span which is also 1/2 span.(3) Analysis and calculation from the above provide guidance to construction of this project, and provide reference for design and construction of other similar structure form of bridge.更多还原