This article proposes a novel concept to mitigate aeroelastic flutter in long-span bridges by allowing the distortion of their cross-section. Specifically, a twin-box bridge deck cross-section, where the space between the boxes can deform as a parallelogram, was analysed. The structural system and aerodynamic forces were formulated to consider the extra degree of freedom of the deck, denoted as the distortion, so the flutter critical wind speed could be calculated for such configurations. A particular case based on the structural properties of the Great Belt East Bridge was analysed. In it, the analytical flutter derivatives of the flat plate were used as suitable approximations. The results show that, when the stiffness of the inner cell is adequately tuned, an increase of around 40%-50% in the critical wind speed can be found. The results hold for different ratios between the torsional and bending natural frequencies of the bridge, proving the potential of the mitigation strategy. • Deformable bridge cross-sections can increase the flutter critical wind speed. • A novel twin-box deck cross-section with controlled distortion is proposed. • The modelling distortionable twin-box cross-sections is explained. • The distortional mode can be tuned by adjusting the stiffness of the inner springs. • A prototypical example shows an increase in the critical wind speed of 40-50%.
Martínez-López et al. (Sun,) studied this question.