表面损伤的斜拉索平均气动阻力特性的试验研究

斜拉索作为斜拉桥的重要受力构件,其风荷载设计在桥梁抗风设计中具有重要意义。斜拉索在生产、运输和安装过程中有可能受到损伤,针对不同程度表面损伤的斜拉索,利用风洞测力试验,研究了亚临界、临界和超临界雷诺数区域损伤程度对斜拉索气动阻力的影响,并得到了表面损伤斜拉索气动阻力的计算方法。结果表明:在一定的风向范围内,斜拉索表面损伤对其气动阻力影响显著,在亚临界区,表面损伤模型阻力系数大于光滑模型;进入临界区后,表面损伤模型的阻力系数则小于光滑模型;在超临界区,二者又比较接近。随着划痕的加深,临界区起始雷诺数提前,且在临界雷诺数区,随着雷诺数的增大,阻力系数减小。对不同损伤程度斜拉索的阻力系数进行拟合,得出相应的计算公式,以方便斜拉索气动阻力的估算。

Tests for average aerodynamic drag characteristics of stay cables with surface damage

Stay cables as important load-bearing members of a cable-stayed bridge, their wind load design is of great significance in anti-wind design of bridges. These cables may be damaged during production, transportation, installation and operation. Here, through wind tunnel tests, aerodynamic drag characteristics of stay cables with different degrees of surface damage were studied. Effects of damage degree in subcritical, critical and supercritical Reynolds number regions on stay cable aerodynamic drag were studied, respectively to obtain the calculation method of damaged stay cable aerodynamic drag. The results showed that within a certain region of wind directions, cable surface damage has significant effects on its aerodynamic drag; in subcritical region, drag coefficient of surface damage model is larger than that of smooth model; after entering critical area, drag coefficient of surface damage model is smaller than that of smooth model; in supercritical area, both of them are close to each other; with increase in scratch depth, initial Reynolds number in critical area is in advance, and in critical Reynolds number region, drag coefficient decreases with increase in Reynolds number; drag coefficients of cables damaged with different degrees are fitted to gain the corresponding calculation formulas convenient to the aerodynamic drag estimation of stay cables.