【作者】 周海波；

【导师】 李明水；

【作者基本信息】 西南交通大学 ， 结构工程， 2013， 硕士

【摘要】 随着经济和科技的进步,现代斜拉桥等大跨桥梁正朝着超大跨度、极度柔性方向发展,大跨度桥梁的风致振动问题显得尤为突出,已成为在设计中的主要控制因素之一。桥梁抖振是由近地风中的紊流成分引起的随机性强迫振动,抖振虽不像颤振那样引起灾难性的失稳破坏,但抖振在任何风速下都有可能发生,过大的抖振响应不仅会影响行车安全和行人的舒适度还会引起结构构件的疲劳破坏；施工阶段还会危及人员和设备的安全。因此桥梁的抖振响应逐渐引起人们的重视,成为桥梁风致振动研究的重点内容之一本文以某大跨斜拉桥为工程背景,主要对斜拉桥施工阶段的最大单悬臂状态进行了线性抖振分析,主要工作包括以下几点：1.根据大跨度斜拉桥的特点及脉动风场的特性,分析了大跨斜拉桥三维脉动风场简化的可行性,将三维的脉动风场简化为多个独立的一维脉动风场,并根据谐波叠加法编制了脉动风场的模拟程序。2.将平均风引起的静风力和脉动风引起的抖振力进行时域化处理,抖振力求解采取Scanlan建议的准定常气动力模型并考虑了气动导纳的影响。对于建立的动力平衡方程,采用直接积分法中的Newmark法进行抖振响应的求解。3.对某大跨斜拉桥最大单悬臂施工阶段进行线性抖振时域分析,并分析气动导纳的影响；最后结合本桥的风洞试验,将理论计算结果和试验结果进行了对比以检验理论计算的合理性。4.对本论文内容进行了总结,得出了一些结论并提出需要注意的事项和不足之处,指出了研究中有待解决的问题。更多还原

【Abstract】 The issue of wind induced vibrations of long span bridges has become one of the main dominating factors in design due to the longer span and higher flexibility. Among the various vibrations buffeting response, a forced random vibration excited by turbulence flow, is the objective of this paper. The buffeting could be excited in any wind speed, though it could not induced the instability collapse such as flutter, the comparatively large buffeting responses may cause safety and comfort of vehicles and pedestrians and may cause the structure damage due to fatigue. In erection state, the buffeting with large amplitude also needs to be controlled in order to secure the personnel and equipments from danger. Therefore, bridge buffeting responses have drawn more attention and in this way have become one of the primary research topics.Based on a long span cable-stayed bridge, the linear buffeting analysis for single largest cantilever erection stage is conducted and the following contents are included:1. According to the characteristics of the cable-stayed bridge and natural wind field, feasibility analysis of three-dimensional fluctuating wind field simplification is conducted by simplifying the three-dimensional gusty wind field into multiple single dimensional gusty wind fields and compiling simulation program using harmonic synthesis method.2. The time domain transformations are conducted for buffeting loadings caused by static wind and gusty wind. The calculating of buffeting forces is achieved by quasi-steady aerodynamic model proposed by Scanlan while considering the influence of aerodynamic admittance. Established the largest single cantilever construction stage structure of the equation of motion and Newmark method which belongs to direction integral method, the solving program is established.3. The linear buffeting analysis in time domain for a cable-stayed bridge in single largest cantilever erection stage and the influence of aerodynamic admittance to the results are conducted. Based on this, a comparison is made with results obtained in the wind tunnel tests and thus the precision of the calculating results could be verified.4. A conclusion is made and some items that should be noticed, short comings, and the issues to be solved are discussed.更多还原