台风作用下跨海斜拉桥的失效机理

发布时间：2019-03-27 06:59

【摘要】：随着大跨斜拉桥的快速建设,桥梁的风敏感性也不断增大。因此,在台风多发地区,研究台风风场特性及其引起的桥梁失效机理具有重要的理论意义和工程价值。本文在分析了桥梁风致破坏的几种主要形式后,重点研究斜拉桥在抖振作用下的失效机理。主要研究内容及结论如下： (1)根据台风的风场特性,采用1949-2011年的热带气旋记录,基于Yan Meng台风模型,拟合出了浙江定海站的台风风剖面拟合值a=0.132。并根据台风的脉动风特性选择了Shama提出的台风湍流强度修正公式进行湍流强度的计算。 (2)采用谐波叠加法,结合基于功率谱密度阵的正交分解(POD),考虑横桥向脉动分量和竖桥向脉动分量的负单点相干性来进行良态风和台风三维风场的数值模拟。良态风的风谱选择《公路桥梁抗风设计规范》(JTG/TD60-01—2004)推荐的Kaimal横桥向谱和Panofsky-McCormick竖桥向谱,顺桥向谱选用对应的Kaimal谱；台风风谱选用根据实测拟合的台风谱,顺桥向谱与良态风一致。 (3)应用CFD二维流体数值模拟计算斜拉桥主梁从-10。到10。的三分力系数,绘制三分力系数曲线。应用三维流体数值模拟计算桥塔的阻力系数,得到桥塔7个控制断面的阻力系数。在ANSYS中建立斜拉桥的有限元模型,对于抖振力的气动导纳采用等效风谱法,而自激力的添加则在ANSYS中编程进行实现。 (4)对两种不同风场下的斜拉桥分别进行主梁和斜拉索的抖振分析。计算结果显示,台风作用下桥梁的位移风振系数比良态风的大；且台风作用下桥梁主跨跨中处的竖桥向位移风振系数特别大,值得引起注意。无论在在良态风还是台风作用下,斜拉索的强度安全是有保障的。同样的风速下台风风场作用下的斜拉索疲劳损伤远远大于良态风风场的疲劳损伤；台风作用下随着风速的增大斜拉索的疲劳损伤显著增大,斜拉索的疲劳损伤对风速十分敏感。
[Abstract]:With the rapid construction of long-span cable-stayed bridges, the wind sensitivity of bridges is increasing. Therefore, it is of great theoretical significance and engineering value to study the characteristics of typhoon wind field and the mechanism of bridge failure caused by typhoon in the areas where typhoons occur frequently. This paper focuses on the failure mechanism of cable-stayed bridges under buffeting after analyzing several main forms of wind-induced failure of bridges. The main research contents and conclusions are as follows: (1) according to the characteristics of typhoon wind field, using the tropical cyclone records from 1999 to 2011 and based on typhoon Yan Meng model, the fitting value of typhoon wind profile of Dinghai Station, Zhejiang Province, is fitted to a = 0.132. According to the fluctuating wind characteristics of typhoon, the correction formula of typhoon turbulence intensity proposed by Shama is selected to calculate the turbulence intensity. (2) numerical simulation of three-dimensional wind field of good state wind and typhoon is carried out by harmonic superposition method combined with orthogonal decomposition of (POD), based on power spectral density matrix considering negative single point coherence of transverse and vertical fluctuating components. The wind spectrum of good state wind is selected in the Code of Design for Wind Resistance of Highway Bridges (JTG/TD60-01-2004). The Kaimal transverse bridge spectrum and the Panofsky-McCormick vertical bridge spectrum recommended by the Code of Design for Wind Resistance of Highway Bridges (Kaimal) are selected, and the corresponding Kaimal spectra are selected along the bridge direction spectrum. Typhoon wind spectrum is selected according to the measured typhoon spectrum, along the bridge spectrum is consistent with the good wind. (3) using CFD two-dimensional fluid numerical simulation to calculate the main beam slave-10 of cable-stayed bridge. To 10. The curve of three-component force coefficient is drawn. The three-dimensional fluid numerical simulation is used to calculate the resistance coefficient of the bridge tower, and the resistance coefficients of the seven control sections of the bridge tower are obtained. The finite element model of cable-stayed bridge is established in ANSYS. The equivalent wind spectrum method is used for the aerodynamic admittance of buffeting force, and the addition of self-excitation force is realized by programming in ANSYS. (4) the buffeting analysis of two kinds of cable-stayed bridges with different wind fields is carried out. The results show that the displacement wind vibration coefficient of the bridge under the action of typhoon is higher than that of the good wind, and the wind vibration coefficient of the vertical displacement at the middle of the main span of the bridge under the action of typhoon is very large, which deserves attention. No matter under the action of good wind or typhoon, the strength safety of stay cables is guaranteed. Under the same wind speed, the fatigue damage of cable under the action of typhoon wind field is much greater than that of good wind field, and the fatigue damage of cable under the action of typhoon increases obviously with the increase of wind speed, and the fatigue damage of cable is very sensitive to wind speed.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.27

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