Sotirios Vardakos joins HNTB as Technical Director – Tunnels and National Tunnel Practice Consultant

Veteran tunneling professional brings extensive experience in the underground engineering realm for transportation and infrastructure

AUSTIN, Texas (July 13, 2022) –Sotirios Vardakos, PE, PhD, has joined HNTB Corporation as a national tunnel practice consultant and associate vice president. In this role, he will focus on expanding HNTB’s tunneling business in the Central Texas region, and nationally, as one of the key technical resources to our transportation and infrastructure clients across the U.S.


Based in HNTB’s Austin office, Vardakos brings more than 20 years of geotechnical, tunnel engineering and research experience. He has been involved in various projects ranging from bored tunnels by tunnel boring machine, mined tunnels and caverns by sequential excavation method, cut and cover structures, and other complex underground structures for major transportation, water and wastewater tunnel, and marine projects.

“As the U.S. is looking to improve mobility and bring major overhaul to our aging infrastructure, underground solutions have been considered more often than ever,” said Sanja Zlatanic, HNTB national tunnel practice chair, senior vice president and HNTB Fellow. “Vardakos’ commitment to technical excellence, determination toward implementing innovations, and tenacity in terms of advances in the tunnel industry, enable him to lend his expertise to our foundation clients and help fulfilling our long-standing commitments to state-of-the-art quality delivery. We are thrilled to welcome him to HNTB.”

Before joining HNTB, Vardakos served as a senior lead consultant and senior technical principal in another major consulting firm in the U.S. He served as task lead and subject matter expert on several signature underground engineering projects; most recently, he was a principal investigator and deputy project manager for task orders by the Federal Highway Administration including research on the design practice of modern large diameter highway tunnels in the United States.

Vardakos is Secretary of the American Society of Civil Engineers Underground Engineering and Construction Committee, an active member of the International Tunneling Association, the Underground Construction Association’s working Group 14 on Mechanized Tunneling, and the American Rock Mechanics Association.

Vardakos received his master’s and PhD in civil and environmental engineering from Virginia Polytechnic Institute and State University, and a master’s of science in mining engineering and metallurgy — geotechnology and tunneling track– from the National Technical University in Athens, Greece. He is a registered professional engineer in New York, Colorado and Texas.