基于风致静动力稳定性的超大跨径桥梁主梁比选研究

Selection of Main Girder for Super Long-span Bridges Based on Wind-induced Static and Dynamic Stability

为寻求适用于超大跨度桥梁的具有更优气动特性的主梁断面,推动我国超大跨桥梁建设的发展,针对超大跨度桥梁原型设计中提出的5种主梁断面形式,采用CFD数值模拟方法计算得到了各断面的静力和动力气动参数,并进一步计算了对应5种主梁断面桥梁的静风失稳临界风速及颤振临界风速,对比了各断面的静动力稳定性能。结果表明,分离双箱主梁和分离3箱主梁的气动性能优于其他类型主梁断面;单箱主梁和双箱主梁气动特性目前已得到较大程度的优化,3箱主梁气动特性应具有较大的优化空间,椭圆形主梁及重力式主梁气动性能较差,优化价值有限。

In order to find the main girder section with better aerodynamic characteristics for super-long-span bridges and to advance the construction development of super long-span bridges in China, five kinds of main girder section were proposed in the prototype design of super long-span bridges. The aerostatic and aerodynamic parameters of the main girder sections were obtained by the CFD numerical simulation method. The critical wind speeds of aerostatic instability and flutter were further calculated for the five kinds of main girder section respectively. The performance of aerostatic stability and flutter stability of these girder sections were compared. It is shown that （1） two-box girder and three-box girder have better aerodynamic characteristics ; （2） the aerodynamic characteristics of single-box girder and two-box girder have been greatly optimized, and there is great room for optimization of three-box girder, while the aerodynamic characteristics of oval girder and gravity girder are poor, and there is little value for their optimization.