As flutter is a very dangerous wind-induced vibration phenomenon, the mitigation and control of flutter are crucial for the design of long-span bridges. In the present study, via a large number of section model wind tunnel tests, the flutter performance of a superlong-span suspension bridge with a double-deck truss girder was studied, and a series of aerodynamic and structural measures were used to mitigate and control its flutter instability. The results show that soft flutter characterized by a lack of an evident divergent point occurred for the double-deck truss girder. Upper central stabilizers on the upper deck, lower stabilizers below the lower deck, and horizontal flaps installed beside the bottoms of the sidewalks are all effective in suppressing flutter for this kind of truss girder. By combining the structural design with aerodynamic optimizations, a redesigned truss girder with widened upper carriers and sidewalks, and double lower stabilizers combined with the inspection vehicle rails is identified as the optimal flutter mitigation scheme. It was also found that the critical flutter wind speed increases with the torsional damping ratio, indicating that the dampers may be efficient in controlling soft flutter characterized by single-degree-of-freedom torsional vibration. This study aims to provide a useful reference and guidance for the flutter design optimization of long-span bridges with double-deck truss girders.

由于颤振是一种非常危险的风振现象，因此缓解和控制颤振对于大跨度桥梁的设计至关重要。在本研究中，通过大量截面模型风洞试验，研究了具有双层桁架梁的超大跨度悬索桥的颤振性能，并采用了一系列空气动力学和结构措施来缓解和控制它的颤动不稳定。结果表明，双层桁架梁出现了缺乏明显发散点的软颤振。上层甲板上的上部中央稳定器，下层甲板下的下部稳定器以及在人行道底部附近安装的水平襟翼均能有效抑制此类桁架梁的颤动。通过将结构设计与空气动力学优化相结合，重新设计的桁架大梁被认为是最佳的减振方案，该桁架大梁具有加宽的上托架和人行道，以及双下稳定器和检查车辆的导轨。还发现临界颤振风速随着扭转阻尼比的增加而增加，表明阻尼器在控制以单自由度扭转振动为特征的软颤振方面可能是有效的。本研究旨在为双层桁架梁大跨度桥梁的颤振设计优化提供有益的参考和指导。还发现临界颤振风速随着扭转阻尼比的增加而增加，表明阻尼器在控制以单自由度扭转振动为特征的软颤振方面可能是有效的。本研究旨在为双层桁架梁大跨度桥梁的颤振设计优化提供有益的参考和指导。还发现临界颤振风速随着扭转阻尼比的增加而增加，表明阻尼器在控制以单自由度扭转振动为特征的软颤振方面可能是有效的。本研究旨在为双层桁架梁大跨度桥梁的颤振设计优化提供有益的参考和指导。