Damage analysis of a reinforced concrete rigid-frame bridge under combined strong earthquake and wave action

The combination of strong earthquakes and wave action may pose risks to the safety of sea-crossing bridges during their service life, resulting in damage to the bridges. To investigate the damage evolution laws of reinforced concrete rigid-frame bridges under combined earthquake and wave action, a novelty simplified numerical method was developed, which was then verified using the results of underwater shaking table tests on a bridge pier. Then, a reinforced concrete rigid-frame bridge modelled by nonlinear fibre damage elements was established and a damage evaluation method was proposed to evaluate the seismic damage evolution processes of the bridge under different wave environments, including various earthquake-wave phase differences, wave directions and wave levels. The obtained results show that the simultaneous effects of earthquakes and waves may increase or decrease bridge damage, which is related to earthquake-wave phase differences. The simultaneous effects of earthquakes and longitudinal waves significantly exacerbate bridge damage compared to those of earthquakes and transverse waves. For the bridge in the largely intact status, the bridge damage index increases with greater wave level. For the bridge in the slight damage status, wave action slightly increases bridge damage at the low-intensity phase in the latter part of the seismic record.