【作者】 江德增；

【导师】 王荣辉；

【作者基本信息】 华南理工大学 ， 结构工程， 2010， 博士

【摘要】 斜塔斜拉桥因其独特的景观效果和力学效果,在城市桥梁中得到了广泛的应用。其倾斜的索塔和较宽的桥面宽度,给结构受力计算带来了一系列问题,如宽截面主梁的计算方法、桥梁结构的非荷载效应、索力优化理论和斜塔、主梁的施工控制等等。本文以中山板芙二桥这座斜塔斜拉桥为工程背景,对斜塔斜拉桥的空间计算理论和施工、运营过程的力学行为进行分析研究。主要完成了以下的研究工作:(1)针对边主肋截面主梁的构造和受力特点,将两侧边主肋视为Timoshenko梁子单元,将桥面板视为板梁子单元,根据子单元间的变形协调关系,组拼成一种能够考虑剪力滞后效应的组合板梁单元。并通过UPFs的二次开发技术,在大型通用有限元软件平台上,实现了用户单元。(2)在组合板梁单元的基础上,研究温度效应、收缩效应和徐变效应的计算方法。先将边主肋子单元、桥面板子单元的非荷载效应等效为子单元的节点荷载,再通过转换矩阵,将各子单元的节点荷载转换到组合板梁单元上,最后用等效节点荷载进行结构分析,获得结构的温度、收缩和徐变荷载效应。(3)进行板芙二桥的温度场实测试验。根据实测数据,提出适合于结构复杂温度场的分区描述方法。即按主梁和索塔各组成构件的温度分布规律,分别提出各构件的温度场模式,包括一维温度场和二维温度场。根据实测数据,拟合各构件温度场模式中的待定参数,为广东地区同类截面桥梁结构温度效应分析提供温度场参考模式。(4)结合弯曲能量最小法和影响矩阵法两种方法对确定板芙二桥的合理成桥状态。针对板芙二桥的结构特点,采用单一的优化方法不能获得令人满意的成桥索力。对此,提出了二次优化的思路,即首先通过弯曲能量最小法初定成桥状态,然后再运用影响矩阵法进行微调。合理成桥状态确定后,再根据成桥状态进行施工倒拆分析,从而得到合理施工张拉力,在计算过程中收缩徐变的影响通过等效节点荷载考虑,这样只需进行一次倒拆分析便可以得到合理的施工张拉力,从而提高了索力优化的效率。(5)基于上述研究成果,建立结构空间有限元分析模型,对板芙二桥施工、运营过程中力学行为进行分析研究。研究包括:主梁的剪力滞效应;温度变化对结构变形和内力的影响;主梁和斜塔的长期变形和内力预测。另外,还进行了塔墩梁连接区域局部应力分析。考虑到组合板梁单元在细部应力分析的不足,在分析塔墩梁连接区域局部应力时,连接区域采用实体单元,其他区域采用板梁单元。通过这些研究,为斜塔斜拉桥的设计和施工提供参考。更多还原

【Abstract】 The type of inclined pylon cable-stayed bridge is widely used in the city. The inclined pylon and wide deck bring a lot of difficulties for structural computation, such as computational method of the girder, non-load effect, cable tension optimization theory, and the construction control of inclined pylon and girder. Based on Banfu No.2 Bridge in Zhongshan city, this thesis studies the spatial computational theory and the mechanical behavior during construction and operation. The main research work in this thesis is as follows:(1) Based on the characteristics of structure and mechanics, the two side main ribs are considered to be Timoshenko beam sub-element, and the deck is considered to be plate beam sub-element. According to the compatibility of deformation among elements, one assembled plate beam element is obtained, and this element can take into the shear lag effect. Through the secondary development of UPFs, the user element is realized on the finite element software platform.(2) On the basis of assembled plate beam element, the computational method of thermal effect, shrinkage and creep effect is studied. The non-load effect of side main rib and deck is equivalent to be the node load of sub-element. Then the node load of each sub-element is converted into the assembled plate beam through transition matrix. Then structural analysis uses the equivalent nodal load, and the thermal effect, shrinkage and creep effect are obtained.(3) The temperature field experiment of Banfu No.2 Bridge is performed. According to the measured data, the regional temperature field is presented. That is: according to the temperature distribution rules of girder and pylon, the temperature field of each member is presented, including one-dimensional and two-dimensional temperature field. Based on the measured data, the parameters of each temperature field are fitted. Then it can provide reference for the thermal effect analysis of the similar section in Guangdong province.(4) The reasonable finished state is determined through the minimum bending energy and influence matrix methods. For the Banfu No.2 Bridge, the single method can not obtain reasonable cable tension. Therefore, twice optimum approach is presented. The process is: the initial finished state is determined through the minimum bending energy, and then the influence matrix method is used to adjust some cable tension. After the reasonable finished state is determined, the backward analysis is carried on, and the reasonable construction tension is obtained, the shrinkage and creep are considered through the equivalent node load. As a result, the reasonable construction tension can be obtained through only once analysis, and the cable tension optimization efficiency is increased.(5) Based on above analysis approach, the spatial finite element model is built to analyze the mechanical behavior during construction and operation. The contents are the shear lag effect of girder, the structural temperature effect, and the forecast of long-term deformation and internal force. Besides, the local stress among pylon, pier and girder is analyzed. Duo to the assembled plate beam element is weak in analyzing local stress, the analytical area selects solid element, the other area selects assembled plate beam element. Through all the research, it provides reference for the design and construction of inclined pylon cable-stayed bridge.更多还原