台风环境大跨度廊桥非平稳抖振分析及舒适度评估

Non-stationary buffeting analysis and comfort assessment of long-span corridor bridge in typhoon environment

以东南沿海某大跨度廊桥为工程背景,建立了风振分析有限元模型.基于台风湍流演变谱模型,对台风非平稳湍流场进行模拟与验证,开展台风环境下大跨度廊桥非平稳抖振分析及舒适度评估,并与相同平均风速下基于平稳湍流谱获得的抖振分析结果进行对比.结果表明,在时变平均风较大时段内,非平稳风速幅值明显增强,相应的非平稳抖振加速度高于平稳抖振结果.平稳与非平稳抖振竖向峰值大于横向抖振峰值,竖向与横向抖振峰值均在规范规定的最佳舒适度限值内,而非平稳抖振峰值较平稳抖振峰值更加接近规范舒适度限值.因此,考虑台风湍流非平稳特性开展大跨度廊桥抗风设计更加安全合理.

A finite element model of a certain bridge at the coastal area in Southeast China was established and regarded as the engineering background.Based on the typhoon turbulent evolution spectrum model,the non-stationary turbulent wind field were simulated and validated.Non-stationary vibration analysis and comfort assessment for the long-span corridor bridge in the typhoon environment were carried out.The analysis results were compared with those obtained by a stationary turbulent spectrum with the same mean wind speed.The results indicate that during the periods with high time-varying mean wind speeds,the amplitude of the non-stationary wind velocity significantly increases.The acceleration of the non-stationary vibration is higher than that of the stationary vibration.The vertical peak vibration values of stationary and non-stationary vibrations are greater than the horizontal peak vibration values.However,both vertical and horizontal vibration peak values fall within the ultimate comfort limits in the code.Furthermore,the non-stationary vibration peak values are closer to the comfort limit in the code than the stationary one.Therefore,considering the non-stationary characteristics of typhoon turbulence to conduct wind-resistant design for long-span corridor bridges is safer and more rational.