is a Senior Technical Principal and Supervising geotechnical and tunneling Engineer at WSP experienced in geotechnical and tunneling engineering analysis, design and research. Dr. Vardakos has served as Lead Engineer in the WSP-New York office for more than 5 years and as Geotechnical Manager for the WSP-Chicago office from 2010 to 2017. He has been involved in various projects ranging from design and analysis of deep excavation support systems, TBM tunnels and caverns, major highway and transit projects as well as marine projects. He serves as principal investigator for several Federal Highway Administration research projects for tunnels and advanced geotechnical exploration. Sotirios serves as Secretary of the ASCE GI Underground Engineering and Construction Committee.