【摘要】 台风灾害频发以及大跨径桥梁塔高、质轻和阻尼弱的特点,台风作用下大跨径桥梁的安全评估十分必要,大跨径桥梁三维台风风场合理模拟是面临的首要问题。利用三次样条函数,模拟台风时变平均风速;采用更新时变平均风速的谐波合成法,实现台风风速脉动部分的数值模拟;并考虑空间点群风速相关性,建立三维台风风场模拟方法。基于进化谱理论,推导非均匀调制进化功率谱(简称进化谱),建立台风风场模拟验证方法;通过对比进化谱与模拟功率谱,对台风模拟结果进行验证。选取沿海地区某大跨斜拉桥为例,应用构建的三维台风风场模拟与验证方法,进行实例桥梁风场分析。结果表明,采用更新时变平均风速的谐波合成法,并考虑空间点群风速相关性,可实现三维台风风场的模拟。更多还原

【Abstract】 Due to hurricane disasters’ frequently occurring and long-span bridges’ features of high-pylon,light weight and weak damping,performing the safety assessment of long-span bridges under the action of hurricanes is necessary. Reasonable simulation of hurricane three-dimensional wind field is the chief problem to be faced. Firstly,adopting cubic spline functions,the time-varying average wind speed of hurricane was simulated. The harmonic synthesis method was adopted to update time-varying average wind velocity and then to realize the simulation of fluctuating parts of hurricane wind speed. Considering the correlation among nodes’ wind velocities in space,the three-dimensional wind field simulation method for hurricanes was established. Secondly,based on the evolutionary spectrum theory,the nonuniformly modulated evolutionary power spectrum briefly called the evolutionary spectrum was derived,the verification method for hurricane wind field simulation was established. Through comparing the evolutionary spectrum and the simulated spectrum for hurricane,the hurricane wind field simulation results were verified. Finally,a case study of a longspan cable stayed bridge in coastal area was selected. The methods of hurricane wind field simulation and validation were used in the case study. The results showed that using the harmonic synthesis method to update the time-varying mean wind velocity and considering the correlation among nodes ’ wind velocities in space,the simulation of hurricane threedimensional wind field can be realized.更多还原