不同粗糙度斜拉索气动力特性和风荷载计算方法研究

摘要

Most parts of wind loads on a large span cable-stayed bridge are caused by cables.It is very important to determine wind forces on cables exactly for bridge design and analysis.Through wind tunnel tests,aerodynamic forces of 8 types of cables with different surface roughness were measured,the influences of surface roughness on Reynolds number effect and aerodynamic force characteristics were studied,the maximum wind load on a cable of a practical bridge was calculated.Results showed that the cable surface roughness has obvious effects on aerodynamic force;with increase in the cable surface roughness,Reynolds number effect decreases gradually;for different surface roughness of a cable,wind velocities corresponding to the maximum wind loads are different;for real bridge design,the maximum wind loads of cables should be determined according to their surface roughness.%大跨径斜拉桥斜拉索上的风荷载对主梁的位移和内力的贡献占全桥的主要部分,准确掌握斜拉索上的风荷载,对于桥梁的抗风设计具有重要的意义.通过风洞试验,得到了8种具有不同表面粗糙度斜拉索的气动力系数随雷诺数的变化规律,研究了粗糙度对斜拉索雷诺数效应和气动力特性的影响,以实桥为例分析了斜拉索最大风荷载的计算方法.结果表明:斜拉索表面的粗糙度对气动力具有明显的影响,随着粗糙度的增大,雷诺数效应随之减弱;不同粗糙度的斜拉索,最大风荷载对应的风速不同,计算方法也不同,实桥设计时应根据斜拉索的具体表面粗糙状态确定其最大风荷载的数值.