Shear Wave Velocity and Seismic Analysis Procedures

The American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications and AASHTO Guide Specifications for LRFD Seismic Bridge Design are being revised to include the direct use of the site class based on the time-average shear wave velocity (VS) in the upper 100 feet of a geologic profile, rather than average Standard Penetration Test (SPT) blow counts or other methods. Due to the greater emphasis on VS measurements in AASHTO procedures, the Missouri Department of Transportation (MoDOT) would like to explore methods to determine VS profiles at a project site that could be done in the preliminary stages without having to deploy a drill rig, Cone Penetration Test (CPT) rig, or crew to obtain the data. The goal of the proposed project is to update and refine seismic site investigation and analysis procedures in anticipation of upcoming changes to AASHTO specifications.