大跨度斜拉桥拉索的抖振响应计算方法

Calculation method of buffeting response for stay cables of long⁃span cable⁃stayed bridge

为完善大跨度斜拉桥拉索的抖振响应计算方法,分析了桥梁抖振反应谱法的不足之处,给出了适用于大跨度斜拉桥拉索的气动阻尼计算公式。结合气动阻尼计算公式,对桥梁抖振反应谱法进行改进,进一步提出了适用于大跨度斜拉桥拉索的顺风向抖振响应均方根值的近似计算公式,并对公式的适用性和影响因素进行了分析。研究结果表明:当风速大于40 m/s且拉索无量纲垂度参数在0.76~2.29之间时,该公式具有良好的准确性。运用该公式能方便有效地计算斜拉索的顺风向抖振响应均方根值,可为相关研究及工程分析提供有效方法。

In order to improve the buffeting response calculation method for cables of long-span cablestayed bridge,the shortcomings of bridge buffeting response spectrum method are analyzed.Based on bridge buffeting response spectrum method,the aerodynamic damping calculating formula suits for cables in long-span cable-stayed bridge is given,and the approximate formula for the cable buffeting response root mean square along-wind in long-span cable-stayed bridge is proposed.The applicability of the approximate formula is analyzed.The results show that the approximate formula has a good accuracy when the wind speed is higher than 40m/s,meanwhile the sag parameter is between 0.76 and 2.29.The root mean square of cable buffeting response along-wind can be calculated conveniently by this formula,which can provide buffeting response study and engineering analysis with an effective method.