Aerodynamic Challenges in Major Chinese Bridges

Abstract

<p>This paper presents recent advances in aerodynamic studies of flutter instability , vortex induced vibration , and stay cable vibration , undertaken to address the most formidable challenges of long-span bridge design. Aerodynamic stabilization for long-span suspension bridges is introduced, followed by an aerodynamic feasibility study of a 5 000 m-span suspension bridge. It seems that the intrinsic limit of span length due to aerodynamic stability is about 1 500 m for a traditional suspension bridge, but either a widely slotted deck or a narrowly slotted deck with vertical and horizontal stabilizers could provide a 5 000 m suspension bridge with high enough critical flutter speed. Since cable-stayed bridges have good intrinsic aerodynamic stability, rain-wind induced vibration and mitigation are discussed as the primary concern encountered in the design of most long-span cable-stayed bridges. It is possible to increase the span length of cable-stayed bridges in the near future while ensuring aerodynamic stability. Compared to suspension bridges and cable-stayed bridges, arch bridges have relatively shorter span and higher stiffness. Consequently, only one of the ten longest-span arch bridges, namely Shanghai's Lupu Bridge, suffers vortex-induced vibration as described in the paper. An increase m span length of arch bridges should not be influenced by aerodynamic requirements.</p>