【作者】 陈爱军；

【导师】 邵旭东；

【作者基本信息】 湖南大学 ， 桥梁与隧道工程， 2005， 硕士

【摘要】 无背索斜拉桥是一种全新概念的桥梁结构形式,它利用塔柱倾斜来平衡桥面恒载和活载,不设背索,丰富了桥梁结构和景观之间的协调关系,达到了造型优美独特的效果,打破了传统桥梁设计理念。无背索斜拉桥虽然结构受力比常规的直塔斜拉桥复杂得多,但是,它优美独特造型和杰出的景观效果得到了广泛的认可,并越来越多的得到工程界的应用。因此,对这种桥型的合理结构型式进行探索和研究,为同类型桥梁结构的设计和施工提供一定的借鉴和参考均具有十分重要的现实意义。本文以长沙市洪山大桥为工程背景,参照Alamillo桥和其他同类桥型的相关资料,借助平面及空间有限元分析方法这一手段,从设计的角度通过改变一些重要的设计参数对无背索斜拉桥的合理结构型式进行了探讨。主要从以下几个方面着手。1.从无背索斜拉桥不同于常规的斜拉桥的受力特点出发,比较了无背索斜拉桥与常规直塔斜拉桥的力学行为差异。结合收集到的国内、外目前已建和在建的10座无背索斜拉桥的相关资料,根据塔、梁、索的布置形式对其进行结构体系的分类,通过大量的平面和空间有限元计算分析得出带辅助孔的刚构体系既可以减小主梁跨中挠度又可以减小斜塔柱向主跨侧前倾的纵向和竖向位移,还可以大大提高结构的竖向刚度和自振频率。2.通过改变洪山桥斜塔柱和主梁的设计参数,如塔、梁重量的增减和刚度的变化、斜塔合理倾角的选取、主梁结构选型和截面形式、拉索在塔内的锚固位置和形式、主梁无索区长度和辅助孔的跨度以及主梁梁端连接构造和主梁施工方法的合理性等对结构受力的影响来探讨大跨无背索斜拉桥的合理结构型式。3.采用频率法弦振理论简化计算索力的公式对洪山桥在挂索期间的索力进行测试计算,通过测试计算结果来对洪山桥索力的变异性和敏感性进行分析。4.最后,综合计算数据得出结论、提出有待研究的问题。更多还原

【Abstract】 The cable-stayed bridge with no backstays is a new concept bridge construct. With the elimination of the backstays, the inclined pylon would rely on its own dead weight, serving as a counterbalance to support the dead loads and live loads on the deck. It would enriched the harmonious relationship between bridge construct and natural landscape, In addition, the particularly exquisite shape would be formed, and the conventional design concept would be broken free from the upright pylon in conventional cable-stayed bridges. Though its mechanical behavior is more complicated than the upright pylon in traditional cable-stayed bridge, the cable-stayed bridge with no backstays not only has been widely accepted but also has been getting more and more applications because of its particularly exquisite shape and outstanding effect of natural landscape. So it is very valuable to research the reasonable structural system and provide some reference for the design and construction of the congener bridge. In this paper, refers to the Alamillo bridge and other bridge of the same bridge type, some studies on the reasonable structural form of no back-stays cable-stayed bridge are carried out by using the plane and space FEM in which the paper changes some important parameters from the point of design based on the Hongshan Bridge, Changsha, Hunan Province, China. The contents are as the following: 1. The paper contrasts the difference of the mechanical behavior between the cable-stayed bridge with no backstays and the traditional upright pylon cable-stayed bridge. Referring to the information about the ten congener bridge built and building and classifying the structure system according to the different disposal form of the towers, the girders and the cables, it draws a conclusion that rigid structure with auxiliary span can minishes both the deflection at the middle of girder’s span and the longitudinal and the vertical displacement of the inclined pylon leaning to the side of the main span. At the same time, it can also increase the vertical stiffness and the natural logarithm of the structure. 2. This paper researches the rational structural system of the large span cable-stayed bridge with no backstays by changing the design parameters of the Hongshan bridge’s pylon and the main girder, such as the increase or decrease of the weight and the variety of the rigidity to girder and tower, the selection of reasonable obliquity to inclined pylon, the selection of structural system and sectional type, the location and form of the anchors within inclined pylon, the length of auxiliary span and no-cable area of girder, the reasonable join constitution of girder end and construction technique of girder. 3. The variability and the sensitivity of the cable force of the Hongshan bridge is analysed though the results of the cable force which was tested by the apparatus during the cable installation and calculated by the simplified formula of chord vibrant theory and frequency method. 4. At last, this paper draws the final conclusions and puts forward the problems to be solved.更多还原