Because of the compelling need to reopen vehicular access routes to Sikeston, Cape Girardeau and St. Louis following a devastating earthquake, Missouri Department of Transportation initiated a study of those portions of US 60 and MO 100 that have been officially designated as emergency vehicle priority access routes. The primary objectives of this study were twofold. Objective 1 was to establish a current subsurface and earthquake design geographic information systems (GIS) database for areas in proximity to designated portions of US 60 and MO 100 (includes counties of Butler, Stoddard, New Madrid, Franklin and St. Louis). Objective 2 was to conduct detailed earthquake assessments at two sites along designated emergency access route US 60. Databases have been established for current subsurface and earthquake design data for the US 60 corridor in Butler, Stoddard and New Madrid counties and for the MO 100 corridor in Franklin and St. Louis counties. These databases serve as the beginning of a larger regional or statewide database for future development and usage by Missouri Department of Transportation. Detailed earthquake site assessments were conducted for two critical US 60 roadway bridge sites (Wahite Ditch Bridge and St. Francis River Bridge). Liquifaction potential, slope stability, flooding potential, abutment stability, and structure stability analyses were performed at both sites for selected worst case scenario synthetic bedrock ground motions based on New Madrid source zone earthquakes with 2% and 10 % probabilities of exceedance in fifty years
