Validation of Tsunami Design Guidelines for Coastal Bridges

US Transportation Collection2021PDFTech ReportLynett, PatrickThio, Hong KieScott, MichaelMurphy, TomShantz, TomShen, Jian-DzwanOregon Department of Transportation. Research SectionUnited States. Department of Transportation. Federal Highway AdministrationOregon. Dept. of Transportation. Research SectionUnited StatesBridge designBridgesCoastal engineeringCoastsDynamic loadsGeotechnical engineeringHydrodynamicsTsunamistsunami loadstsunami load calculationstsunami loading on bridgesFHWA-OR-RD-21-09Final ReportThis paper details a Transportation Pooled Fund Study, TPF-5(307), that included Alaska, California, Hawaii, Oregon (lead state), Washington, and the Federal Highway Administration. The research goal was to update guidelines as a foundation for review by the respective AASHTO sub-committee(s). This report focused on bridges for the Western United States. Five major efforts were completed: 1. Updated probabilistic tsunami hazard mapping to include wave-heights, velocities, and inundation levels at the 1000-year recurrence interval. This was completed for all aforementioned states at varying detail (10m through 60m); 2. Uncertainties and bias between models were examined to find areas where they agree and potential areas where the study could identify conservative estimates for optimization. 3. Analysis of site-specific tsunami hazards was developed. Two methods (level 1 and level 2) are presented to detail local tsunami hydrodynamics; 4. Loading are detailed and recommendations for equations presented based on research findings. Three load cases, including conditions showing upward lift were modeled and equated. Bridge skew, slope, and super-elevation were examined. Debris was considered. 5. Geotechnical considerations were also discussed.121