Gridded earthquake ground motions for the 2023 AASHTO Design Specifications

For designing bridges to safely resist earthquakes, the 2023 editions of the AASHTO (1) Guide Specifications for LRFD Seismic Bridge Design, (2) LRFD Bridge Design Specifications, and (3) Guide Specifications for Seismic Isolation Design provide risk-targeted design ground motions via this data release and the corresponding USGS Seismic Design Web Services (listed below). The web services spatially interpolate the gridded ground motions of this data release for user-specified latitudes and longitudes. All of the data files within the regional "Child Items" below were derived from respective USGS National Seismic Hazard Models (cited below). Details of the derivation will be added to this data release upon publication of the 2023 AASHTO Design Specifications.