Wind-induced vibration test and aerodynamic optimization of a long-span suspension bridge with steel box girder located in cliffy mountainous areas

In order to understand the wind-resistant performance of a long-span suspension bridge with steel box girder located in cliffy mountainous areas, a practical engineering project was taken as the analysis example. The three-dimensional finite element model of the bridge was established to extract the modal characteristics, and the sectional wind tunnel test was designed accordingly to test the flutter performance of the bridge at different angle of attack. The aerodynamic shape of the steel box girder was optimized in accordance with different aims, and the effectiveness of the countermeasures was evaluated based on the critical flutter wind speed and the vortex-induced vibration (VIV) performance. The results show that the bridge with higher crash barrier is of worse flutter stability at positive angles of attack. Setting the central vertical stabilizer on the bridge deck or the guide plate on the wind fairings could improve the critical flutter wind speed of the bridge. However, the two countermeasures have different effects on the VIV of the bridge. The set of the stabilizer makes the bridge have the possibility to produce VIV at both positive and negative angles of attack, while the set of the guide plate makes the bridge have the possibility to produce of VIV at positive angles of attack only. Considering that negative angles of attack are dominant for the bridge site, the latter countermeasure shows more advantages. © 2023 Chinese Vibration Engineering Society. All rights reserved.