Coordinated Similarity Theory With a Truncated Method for Floating Bridges Under Combined Earthquakes and Waves

This study investigates the coordinated similarity method and a truncated-model approach for floating bridges subjected to combined earthquake and wave effects. The dimensional relationship between the elastic similarity criterion and the Froude similarity criterion under multi-physics is derived first. The time scale is enlarged by introducing a correction term to account for temporal field dissimilarity, while the geometric scale ratio remains unchanged. Furthermore, based on the “variant design concept” and the “super-stiffness method,” an innovative method for the truncated model is proposed to correct the truncated boundary effects. Validation tests with a geometric scale of 1:100 show that the dynamic responses of the proposed truncated model align well with those of the full-scaling bridge. Under seismic action, the dynamic response of the girder is influenced by mechanical devices, yet its motion amplitude consistently corresponds to the dominant frequency of the seismic acceleration. The resulting error in the spectral characteristics caused by seismic effects is negligible.