The 2,717 state highway bridges incorporated into this study from the WSDOT bridge inventory database were assessed using the BSST analysis methodology detailed previously in this report. Results consist of three types of outcomes: Bridge Damage Levels and Types, Bridge Repair Types, and Bridge Reopening Times. All output is a part of this feature class. Bridge damage types are projected on the basis of both damage level (None, Moderate, Significant), whether a bridge is a special bridge type, and also the types of damage that the bridge will experience (including both direct seismic and secondary earthquake-induced impacts); The projected repair types and reopening times necessary to bring bridges back to a minimum level of functionality that enables their use for emergency response were computed using the methodology specified in the Bridge Reopening Times section. Refer to the BSST Technical Report. The BSST was developed to assess the potential impacts of a CSZ earthquake to highway bridges in Washington State at a system-level as part of the Washington State Transportation Systems RRAP project. The results provided identify the Damage Levels, Damage Types, Repair Types and Reopening Times associated with 2,717 bridges located in Western and Central Washington that were evaluated for this RRAP project. Understanding that this analysis likely constitutes a “worst-case scenario” with respect to bridge damage, the results nonetheless project that the majority of bridges in Washington State will experience moderate to significant damage resulting from a CSZ earthquake. While the majority of bridges that experience damage could be reopened within one year of the earthquake, a substantial number of those bridges (28.7 percent) are projected to take more than a year to reopen—in many cases 2 or more years. The results also project that while many bridges may be reopened after either minor repairs/inspections or the construction of a temporary bypass road, a substantial number of more significantly damaged bridges (797 structures) span bodies of water and will require complete replacement prior to reopening. This suggests that significant gains in roadway corridor reopening times could be gained by focusing on retrofits or upgrades to these more vulnerable bridges that span rivers and other bodies of water. This tool is primarily intended to inform regional highway prioritization for emergency response activities; however, the BSST provides a useful evaluation methodology that could be applied to other regional emergency preparedness and infrastructure assessment studies. This could include studies of bridge infrastructure to other potential seismic events within the region, or at varying jurisdictional levels (i.e., county, local). The BSST also uses currently available seismic, seismically-induced secondary hazard and infrastructure information. As new seismic information becomes available, or as secondary-hazards (e.g., landslides, avalanches) become characterized more comprehensively, such information could be integrated into the current BSST methodology. Similarly, as seismic retrofit activities or other infrastructure improvement projects continue throughout Washington State, or as new infrastructure are built, it will be important that the infrastructure data integrated in the BSST also be updated periodically. Doing so will ensure that planners and infrastructure managers maintain the most current and complete understanding of the network-level seismic risks of a CSZ event to Washington State highways.Please note that all results from the BSST are based on a model and information received from WSDOT. Damages from an earthquake may be different that what is provided here. Liquefaction data was used within the BSST tool. WADNR is the source for liquefaction data and is available here: https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/geologic-hazard-maps#nehrp-site-class-and-liquefaction-susceptibilityUSGS ShakeMap was also used in the BSST tool for a M9.0 Cascadia earthquake and is available here: https://earthquake.usgs.gov/scenarios/eventpage/gllegacycasc9p0expanded_se/shakemap/pga. DHS distributed this data to WSDOT on August 22, 2019.
OwnerThe Washington State Department of Ecology - view all
Update frequencyunknown
Last updated10 months ago
Overview018BridgeDOTDataDepartmentEmergency ManagementOpenPlnngRdwy InfrResiliencyStateTRNTransportationWAWSDOTWashington
Additional Information
KeyValue
dcat_issued2020-04-07T18:50:53.000Z
dcat_modified2023-08-29T18:12:13.269Z
dcat_publisher_nameWSDOT Security and Emergency Operations
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language
harvest_object_idda3d81e9-58a1-40e7-b29a-e865210782eb
harvest_source_id03016d16-b963-4f6a-99b0-8a37574f4576
harvest_source_titleWashington Geospatial Open Data Portal