Three-Dimensional Effects of Tsunami Impact on Bridges

Abstract

Field investigations following major tsunamis in recent years have shown that damage to and loss of bridge structures can cause delays in disaster relief and recovery. The damaged bridges were subject to extreme fluid loads such as uplift due to buoyancy and overturning from wave impacts, and these loads are not currently considered within bridge design practice. In response, some studies regarding fluid-bridge interactions have been done; however, they primarily focused on two-dimensional analyses of the bridge. The objective of this work was to examine three-dimensional fluid-bridge interactions utilizing the computational fluid dynamics solver OpenFOAM with a multiphase fluid solver and a Reynolds-Averaged Navier-Stokes (RANS) based turbulence model. Numerical test cases were validated by existing data from flume tests to examine capabilities of OpenFOAM in modelling fluid-bridge interactions. Subsequently, three-dimensional models were developed to examine geometric modifications to the bridge including skewness, grading and superelevation of bridge decks. These modifications were incorporated to resemble common bridge designs. Results showed a clear correlation between forces on the bridge structures and changes in the geometry of the superstructure and these effects should be properly considered in future designs.