某大跨悬索桥风振响应现场实测与理论对比分析

Comparison between field measurement and theoretical analysis results for a long-span suspension bridge's wind-induced vibration responses

结合东海某大跨悬索桥健康监测系统,同步实测桥面处风速及加劲梁与吊索风振加速度响应,采用统计方法及频谱分析对结构响应长期实测数据进行分析;探讨结构构件风振响应实际特性;将强风作用下加劲梁响应实测值与抖振分析理论结果进行对比研究。结果表明,加劲梁的RMS响应与垂直桥面平均风速基本呈线性关系,加劲梁响应以低频为主,动力特性随风速增大变化不大;吊索振动主要为高频涡振,迎风侧吊索响应明显高于背风侧吊索响应;由于大跨度悬索桥抖振响应计算及实测过程受复杂与不确定因素影响,理论分析结果明显大于实测值。

Based on the structural health monitoring system installed on a long-span suspension bridge, the simultaneous wind speeds at the bridge deck and the wind-induced acceleration responses of the stiffening girder and hangers were recorded. The actual characteristics of the wind-induced vibrations and the comparison between the theoretical results and the measured responses were discussed. The results indicated that the RMS of acceleration responses of the stiffening girder have a linear relationship with the average wind speeds vertical to the bridge deck; and their dynamic characteristics are stable with increase in wind speed; the dynamic response of the hanger under wind is a higher frequency resonance and the resonance frequency increases with increase in wind speed; the buffeting responses with theoretical analysis are significantly greater than the measured ones, the buffeting analysis still needs more refinements.