The technical objective of this project is to develop tsunami loading and design recommendations for bridges that address issues that must be treated differently for bridges than for buildings. These issues include (1) three-dimensional bridge geometries such as deck shape, skew and embankments, whose hydraulic characteristics can lead to channelization, bore entrapment, and shielding; (2) debris impact and debris damming that can greatly increase the forces on a bridge, both during the initial impact of the tsunami waves and during the outflows; and (3) fluid-structure interaction effects that can be significant for particular types of bridges and retrofit strategies, such as the deployment of fenders or in cases with flexible structures. Bridge-specific retrofit strategies will also be explored. Recent advances in the development of parallel processing software and the availability of powerful computational platforms make it possible to simulate these complex effects. Computational fluid dynamics (CFD) modeling will address the effects of three-dimensional hydraulic geometries. The Material Point Method (MPM) will address the effects of debris impact fields and damming by modeling debris explicitly. The Particle Finite Element Method (PFEM), as implemented in OpenSees, will allow researchers to consider the fluid-structure interaction, the effects of the preceding earthquake shaking and the effect of uncertainties. As part of this planning grant, the simulation strategies will be developed sufficiently to guide the detailed design of critical experiments in a NEES2 facility early in FY2015.
Over the past decade, tsunamis have caused hundreds of thousands of deaths and hundreds of billions of dollars of damage. The loss of critical lifeline structures has exacerbated these catastrophes by delaying emergency response efforts and post-event economic recovery. Large tsunamis also threaten at least five U.S. states and numerous U.S. territories. Nearly all past tsunami research has focused on run-up modeling, the development of evacuation strategies, and more recently, on the design of buildings to resist tsunamis. In comparison, little research has addressed the tsunami performance of bridges, and no guidelines are available to design safe and economical tsunami-resistant bridges or to develop retrofit strategies. To these ends, the proposed research will transform the design of tsunami-resistant bridges, and consequently, greatly improve post-event response and recovery efforts. Data from this project will be archived and made available to the public through the NEES data repository. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).
