Hydrodynamic analysis of sea-crossing bridge piers subjected to freak waves

To support growing populations and economic activities, coastal areas are witnessing a surge in critical infrastructure development such as sea-crossing bridges. However, these structures face ongoing challenges in harsh marine environments. Therefore, understanding the hydrodynamics of bridge structures under extreme wave conditions is imperative for designing effective countermeasures. In this study, pier hydrodynamics were investigated using a three-dimensional numerical flume simulated using OpenFoam, focusing on loading characteristics and wave climb differences under freak and linear waves. The results showed that freak waves induce larger surges and forces than linear waves, with a notable ‘bell vibration’ effect near the wave surface. Moreover, peak forces and bending moments were found to increase non-linearly with the ratio of wave height to significant wave height. For double-column piers, transverse alignment concentrates wave climb on the rear side of the front pier, with forces increasing with spacing, while those on the rear pier decrease. Conversely, longitudinal arrangements showed amplified loading effects. These findings provide valuable insights into the hydrodynamic behaviour of bridge piers under freak wave conditions, offering practical implications for the design and protection of sea-crossing bridges.