【作者】 王统宁；

【导师】 刘健新；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2010， 博士

【摘要】 大跨度缆索承重桥梁由于刚度小,在荷载和自然因素作用下的梁端位移较大。梁端位移不仅是梁端附属装置和梁端构造的一个重要设计参数,也是缆索承重体系桥梁健康监测的重要参数之一。因此,研究影响梁端位移的作用因素、结构因素及梁端位移作用效应的组合方法有重大的工程价值和意义。论文以斜拉桥和悬索桥体系为研究对象,采用有限元方法系统研究了产生梁端位移的作用因素；基于可靠度理论研究了梁端位移作用效应组合及组合的分项系数；提出了梁端附属装置和梁端构造位移参数的设计方法。论文的主要研究成果如下：1、系统研究了温度、汽车、静风和地震作用对斜拉桥和悬索桥梁端位移和转角的影响。针对不同的缆索承重桥梁结构形式,明确了需计算的梁端位移和转角类别及计算时应考虑的作用因素。其中关于梁端转角的研究表明：目前梁端附属装置横桥向轴的转角限值(±0.02rad)不能满足所有缆索承重桥梁的要求,需进行针对性的设计。2、系统研究了辅助墩、支座摩阻力和塔梁连接方式对梁端位移和转角的影响,明确了缆索承重桥梁的梁端位移预测时需考虑的结构因素。其中采用刚-塑性刚度模型研究了支座摩阻力对静态下梁端位移的影响,指出在斜拉桥梁端纵向位移计算时需考虑支座摩阻力的影响。塔梁之间弹性索能有效减小汽车、静风和桥塔梯度温差作用下的梁端纵向位移；由于地震动频谱的影响,弹性索并不总是减小地震作用下的梁端纵向位移。3、针对影响梁端位移的作用因素,首次基于可靠度分析的一次二阶矩理论建立了梁端位移作用效应组合方法。根据梁端附属装置的特点确立了梁端附属装置的设计基准期和目标可靠度指标,利用作用的概率分布函数推导了梁端附属装置设计基准期内的最大值分布,并确定了作用效应组合的分项系数。该组合方法的突出优点是充分考虑了作用效应的特性和概率分布,具有明确的可靠度指标,方便和实用。4、基于梁端位移的影响因素和作用效应组合的研究成果,充分考虑了梁端各方向的变位,改进了梁端附属装置和梁端构造的位移参数的设计方法。更多还原

【Abstract】 As the stiffness of long-span cable supported bridges is low, the displacement of the girder always large under load and natural function. Beam-ends displacement is a important design parameters for construction and devices of girder end, and for the bridge health monitoring. So, study on the effect action, construction factor, and the combination for action effects of beam-ends displacement that has great engineering values and important meaning. In the paper, it take cable-stayed bridge and suspension bridge as object of study, action and structure factor that effect beam-ends displacement was analyzed using FEM method, and the combined effect of girder displacement has studied based on the reliability theory. In turn, design method of displacement parameters for devices of girder end was put forward. The main conclusions are as follows:1. Systematically study the influencing factor such as temperature, vehicle, static wind and earthquake which how to influence beam-ends displacements. For different cable surpported bridge, displacements and rotation angles which need calculation in bridge design was definited. which action is must be take into account when calculating beam-ends displacements was also provided. The results of studied on rotation angle show that the current limit rotation angle(±0.02rad) can not meet the needs of all of cable surpported bridges, it must be specific design.2. The structure factor, such as auxiliary pier, supports frictional resistance, connections between tower and beam, which how to infuence on displacements and rotation angles was studied Systematically, and which structure factor is must be take into account when calculating beam-ends displacements of cable supported bridges was definited. Rigid-plastic model was used to analyze the effection of supports frictional resistance on beam-ends displacement and results indicated that the supports frictional resistance should be include During the cable-stayed bridge displacement prediction. Flexible cable between tower and beam can efficiently decrease the beam-ends longitudinal displacement caused by vehicle, static wind and temperature longitudinal gradient of tower. but it may be enlarge the beam-ends longitudinal displacements under the excitations of earthquake with designated frequency spectrum.3. Based on First-order Second-moment Method on reliability analysis, set up the action effects combination method of beam-ends displacement effects, direct towards the influence factors of beam-ends displacement. Defined the design reference period and target reliability index of girder fixtures according to the characteristic of them, derive the maximum distribution during reference period using the probability distribution function of loads, certain the partial safety factor of action effects combination. The advantages of the combination method are that it is banausic and convenient, and has clear reliability index.4. According to the influence factors of girder displacement and the action effects combination, taking all displacements and rotations of girder end, improving the design methods for displacement parameters of beam-ends devices and construction.更多还原