Modeling and Simulation of Tsunami and Storm Surge Hydrodynamic Loads on Coastal Bridge Structures

Bridge structures along the coasts are often subjected to hydrodynamics loads of various forms and intensities. The most dramatic loads are those due to tsunamis and storm surges as vividly demonstrated by images of the Dec. 2004 Indian Ocean Tsunami and the Sept. 2005 Katrina Hurricane in the Gulf of Mexico. Other loads include wave impact, current induced scour, and floating debris impact. The physics of these hydrodynamic loads are complex in nature and difficult to model analytically. Few current design codes for coastal structures include tsunamior storm surge-induced hydrodynamic effects. Even those that do, the bases for taking the hydrodynamic loads into the design are often grossly simplified and may be overly conservation and/or unreliable. The design of general coastal structures often relies on experimental model simulations. Because of scale effects, it is important to use experimental facilities capable of performing large scale tests. Recently, with the support of the US National Science Foundation under the Network for Earthquake Engineering Simulation Program, Oregon State University has completed the upgrading of a 3-dimensional wave basin to complement its existing 2-dimension large wave flume to support experimental research on tsunami and storm surge effects on coastal structures. This paper (1) briefly describes the physical phenomena of tsunami and hurricane induced water elevation change and inundation at coastal areas, (2) discusses tsunami and storm surge hydrodynamic loads on coastal bridge structures, (3) summarizes the physical experimental facilities at the Oregon State Wave Research Laboratory and selected numerical models at OSU for coupled fluid-structure interaction modeling, testing and simulation, and (4) provides a discussion on the development of comprehensive experimental studies and some challenges in experimental and numerical simulations of large-scale fluid-structure interaction with applications to coastal bridge structures.