拉索对斜拉桥竖向频率的影响研究

The influence of cables on vertical frequency of cable-stayed bridge

基于漂浮式独塔斜拉桥三梁离散弹簧动力学模型,对拉索对斜拉桥竖向振动频率的影响进行了研究。该模型将斜拉索简化为无质量弹簧,将桥塔视为考虑轴力影响的欧拉柏努利梁;同时,将桥面与桥梁交接处截开为两根欧拉柏努利梁。然后基于传递矩阵法基本理论,以长沙某独塔斜拉桥为研究对象,计算了斜拉桥的自振频率和模态,从而基于频率对斜拉桥的竖弯刚度进行评估。最后对普通钢索被替换为CFRP斜拉索后对桥梁整体竖弯刚度的影响进行了研究分析。结果表明,利用所提出的模型可以很好地评估斜拉桥的整体竖弯刚度,并且将钢质拉索更换为CFRP斜拉索能不同程度地提高斜拉桥的整体刚度。

Based on the dynamic model of three beams with discrete springs of the floating single-tower cable-stayed bridge,the influence of cables on the vertical frequency of the cable-stayed bridge is studied.In the model,the stay cables are simplified as springs without mass and the single-tower is regarded as a Euler-Bernoulli beam with consideration of the impact of axial force.At the same time,the bridge deck has been divided into two Euler-Bernoulli beams at the intersection of deck and tower.Then,based on the basic theory of transfer matrix method,the natural frequency and mode are calculated for a single-tower cable-stayed bridge in Changsha,and the vertical bending rigidity of the cable-stayed bridge is evaluated based on the frequency.Finally,the influence on the vertical bending rigidity of the bridge is studied when ordinary steel cables are replaced with CFRP cables.The results show that the model proposed in this paper can be used to evaluate the vertical bending rigidity of the cablestayed bridge,and the CFRP cables can improve the overall rigidity of the cable-stayed bridge to some extent.