【作者】 邱文亮；

【导师】 张哲；

【作者基本信息】 大连理工大学 ， 结构工程， 2004， 博士

【摘要】 自锚式悬索桥以其造型美观、经济、适应性强等优点，越来越受到工程界的青睐，在国内外，已有多座自锚式悬索桥建成和建造中。自锚式悬索桥无论是在施工方面，还是在成桥后的受力方面，与地锚式悬索桥都有很大的区别，存在自身的特点。本文结合工程实际，在自锚式悬索桥的受力性能、极限跨度、极限承载力以及施工控制方面进行了研究和探讨，具体研究内容如下： (1)基于有限位移理论，针对自锚式悬索桥的受力特点，全面考虑大位移效应、主缆垂度效应、初始内力效应、混凝土收缩徐变、预应力损失等因素对自锚式悬索桥的非线性影响，给出了适于自锚式悬索桥非线性分析的有限元方法。利用有限位移理论，对一座跨度240m的自锚式混凝土悬索桥进行了详细分析，发现跨径达到200m的自锚式悬索桥近似满足弹性理论，非线性行为可以忽略；增大主缆矢跨比和加劲梁拱度，可以提高结构刚度，减小活载产生的内力；加劲梁的混凝土收缩徐变对结构内力和变形影响较大；在施工阶段，主梁因压缩和混凝土收缩徐变产生的变形对主缆线形影响很大，在确定主缆空缆线形时应加以考虑。 (2)推导了常见的双塔三跨式自锚式悬索桥和单塔两跨式自锚式悬索桥的极限跨度的表达式，研究了极限跨度与主缆矢跨比λ、边跨与中跨跨度比β、索塔高度与跨度比μ、二期恒载、活载等影响因素的关系。结合目前桥梁常用的材料，考虑主要因素的影响，对混凝土加劲梁和钢加劲梁自锚式悬索桥的极限跨度进行了具体研究，给出了相应的极限跨度。研究结果表明，要想增大自锚式悬索桥的极限跨度，可以采取以下措施：中跨主缆采用较大的矢跨比；主缆和加劲梁采用高强度、轻质材料；尽量减轻二期恒载。 (3)为了分析自锚式悬索桥的极限承载力，首先给出了平面梁单元考虑材料非线性的折减刚度法，建立了考虑滑移非线性效应的钢—混凝土组合梁非线性分析的“双层梁”有限元模型，推导了考虑滑移效应的剪力连接件单元刚度矩阵。 通过对三座实际自锚式悬索桥的弹塑性极限承载力分析，发现对于全桥加载的情况，三座自锚式悬索桥的弹塑性极限荷载安全系数分别为3.00、2.88、3.30；三座悬索桥的破坏均与吊索或主缆的屈服有关，因此吊索和主缆的设计安全系数取值大小应予以重视；采用较小的边跨和中跨的跨度比时，锚固端压重过小，会使结构的极限承载力降低较大。 对万新大桥进一步研究表明，按弹塑性和弹性计算的结果，无论是变形，还是内力，均有较大的差异，说明该桥进入弹塑性阶段，存在显著的内力重分布现象；该桥的无限弹性稳定安全系数远大于弹塑性极限荷载安全系数；加劲梁和索塔的配筋率、主缆的弹性模量、混凝土收缩和徐变对该桥的极限承载力影响不大，但对结构刚度影响明显。 (4)从自锚式悬索桥的成桥状态和主缆矢跨比出发，采用分段悬链线理论计算了成桥主缆线形；考虑自锚式悬索桥主缆线形受主梁变形等因素的影响，利用悬链线理论，计算了主缆空缆状态的线形；研究了考虑非弹性变形时钢丝绳索股无应力长度的计算方法；摘要研究了主缆架设过程中跨度、索长、塔高、温度对线形的影响关系。针对自锚式悬索桥的施工特点，考虑吊索张拉过程中存在大位移非线性、支架接触非线性、混凝土收缩徐变、索鞍顶推、主缆弹性模量非线性等多种非线性因素的影响，编制了适于自锚式悬索桥施工控制的非线性有限元程序。 针对吊索张拉这一复杂的非线性过程，研究了在结构承载力和张拉设备能力等约束条件下，吊索反复张拉次数和接长杆数量的优化方法和脱模状态的确定方法，解决了自锚式悬索桥施工控制中体系转换这一关键问题。对万新大桥施工计算表明，利用该方法，可以通过四次张拉达到理想的脱模状态，三次张拉可以达到满足要求的实际脱模状态。 最后，以最小二乘法为基础，提出了自锚式悬索桥施工过程中的非线性误差调整方法。研究表明，对于施工过程中的索力误差，可以通过部分吊索索力的调整得以消除;而对于主梁和索塔的变形误差，则需要通过全桥吊索索力的调整加以消除，同时获得满足要求的吊索索力误差。 (5)通过模型试验，对自锚式悬索桥的施工过程进行了模拟，对成桥结构进行了静载试验，实测结果与计算结果相吻合，验证了本文对自锚式悬索桥受力性能理论研究的正确性，同时为实桥的施工控制提出了有益的建议。更多还原

【Abstract】 Self-anchored suspension bridges are increasingly appreciated by engineers for their aesthetic look, low cost and high adaptability. Many self-anchored suspension bridges have been completed or are in construction in the world. No matter for.construction or mechanical properties, self-anchored suspension bridges differ from conventional suspension bridge and have their own particularity. Combined with the engineering practice, this paper gives the study and discussion about mechanical properties, limit span, ultimate bearing-capacity and construction control of self-anchored suspension bridge. The main research work covers the following aspects:(1) Based on the finite displacement theory and considering mechanical properties of self-anchored suspension bridge, the nonlinear factors, including sag of main cable, large displacement, initial internal force, concrete shrinkage and creep and loss of prestress, are fully considered, and the finite element method suitable for nonlinear analysis of self-anchored suspension bridges is presented in this paper. Through detailed analysis of a self-anchored concrete suspension bridge with span of 240m by using the finite displacement theory, it is found that a self-anchored suspension bridge with span 200m approximately meets the elasticity theory and the nonlinear behavior can be ignored. When greater the ratio of rise to span of main cable is adopted, the structural rigidity becomes greater and the internal force caused by live load becomes smaller. The concrete shrinkage and creep of stiffening girder has great influence on the internal force and deformation of the structure. Deformation of main girder due to compression and concrete shrinkage and creep has a significant influence on the configuration of main cable at the stage of construction. So it should be fully considered in design of the configuration of main cable.(2) The limit spans of the common twin-tower three-span self-anchored suspension bridges and single-tower two-span self-anchored suspension bridges are deduced. Some factors, such as ratio of rise to span X of main cable, ratio of side-span to mid-span β. ratio of tower height to main span μ, second dead load and live load, are analyzed in this paper. The limit span of the self-anchored suspension bridges with concrete stiffening girder and with steel stiffening girder, are discussed in detail, and the respective limit spans are given. The result shows that the following measures can increase limit span of a self-anchored suspension bridge: a larger ratio of rise to span is adopted for the main cable of mid-span; the main cable and the stiffening girder are made of high strength and light weight materials; and the second dead load is reduced as much as possible.(3) In order to analyze the ultimate bearing capacity of self-anchored suspension bridges, the reduced stiffness method for 2D beam element considering the nonlinearity of material is given, and the finite element model of double-layer beam for nonlinear analysis of steel-concrete composite beams considering nonlinear effect of slip is created. Then, through analysis of ultimate bearing capacity of three actual self-anchored suspension bridges, it is found that for the condition of loading on the entire bridge, the safety coefficients of ultimate bearing capacity of these three bridges are respectively 3.00, 2.88, 3.30. Breakage of these three suspension bridges is related to yield of hanger or main cable. Therefore, attention should be paid to selection of the safety coefficient in design of hanger and main cable. A smaller ratio ofside-span and mid-span leads to too small reaction of the anchor, and causes much reduction of the ultimate bearing capacity. The further study shows that upon break of the bridge, the result based on elastoplasticity and that based on elasticity, no matter for deformation or for internal force, are greatly different, showing that the structure comes to the elastoplasticity stage with a significant redistribution of internal force. The elastic ultima更多还原