中文摘要：

由于大跨度斜拉桥斜拉索的风荷载在全桥风荷载中占很大比重,因此准确掌握斜拉索的风荷载对大桥的设计工作是十分重要的。通过风洞试验,测试斜拉索的阻力和升力,得到力系数随雷诺数的变化规律,证实在临界雷诺数区域有平均升力的产生,其最大升力系数远大于此雷诺数时对应的阻力系数,忽略升力的存在可能导致斜拉索风荷载的计算结果偏小;将阻力系数和升力系数合成为合力系数,并与规范值比较,发现只有当雷诺数超过一定数值之后,规范的算法才是安全的,雷诺数小于此值尤其是在临界雷诺数区域,合力系数比规范值超出较大。针对苏通长江公路大桥和南京长江第二大桥,利用试验结果和规范值,对斜拉索的风荷载分别进行计算分析,发现利用本文方法计算的合力并不随风速的增大单调增长,而是在一定的风速时取得极大值;利用静阵风风速计算风荷载,按桥规计算的结果在某些情况下偏小,建议规范适当考虑气动升力对斜拉索风荷载的贡献。

英文摘要：

As the most part of wind loads on a cable-stayed bridge is caused by the cables,it is very important to master the wind forces on cables exactly for bridge design.By wind tunnel tests,drag forces and lift forces on cables were measured,and change of force coefficient with Reynolds number was obtained.It is found that lift force occurred in critical Reynolds number range,and the maximum of lift force coefficient is much greater than drag force coefficient with the same Reynolds number,so neglecting lift force would lead to lower value of wind force.Resultant force coefficient were combined from drag force coefficient and lift force coefficient,and by comparing with the specification value,results indicate that when Reynolds number is greater than a certain value,the bridge specification value is safe,but when Reynolds number is less than the certain value,especially in critical Reynolds number range,resultant force coefficient is much grater than the bridge specification value.Wind resultant force calculated by test result and the bridge specification were compared by using the parameters of Sutong Yangtse River Bridge and the Nanjing 2nd Yangtse River Bridge,and the results indicate that wind resultant force non-monotonically increases with wind velocity,and it obtains the maximal value in a certain wind velocity.By wind load analysis using static gust velocity,it is found that in some case the bridge specification value of wind load are relatively small.The contribution of lift force to wind load in the bridge specification is suggested to be taken into consideration.