Lessons Learned from the SR-99 Highway Tunnel Project in Seattle, Owner’s Perspective

Geotechnical consultant Gregg Korbin served on the Technical Advisory Board for Washington State DOT for the SR-99 Alaskan Way Viaduct Replacement Tunnel Project. He recently presented to the Vancouver Geotechnical Society on lessons learned from that project, from the owner’s perspective, and fortunately for those of us not in Burnaby, we can watch the recorded version! See below.

The SR-99 highway tunnel under the city of Seattle was designed to replace the waterfront viaduct damaged by the Nisqually earthquake. At time of bid, the 17.5 m diameter EPBM manufactured by Hitachi was the world’s largest TBM. The speaker was a member of WSDOT’s technical review board from design through construction (2009 to 2017). The project faced many technical challenges, and despite a difficult startup, it ended up setting a new standard for the soft ground tunneling industry in terms of ground control and monitoring methodologies. The technical presentation will be from the owner’s perspective. Topics include design and contract approach, TBM issues related to manufacturing, breakdown and rebuild, the management change, TBM performance and ground response from mining, and the court case, as well as the contribution of WSDOT’s technical review board.

Gregg Korbin graduated from UC Berkeley with a Ph.D. in Geological Engineering in 1975. Post graduate research in pre-reinforcement of underground openings and mechanical rock excavation resulted in consulting for the hard rock tunneling industry and hydro projects, mostly on the design side. In 1995 there was an opportunity to consult on the South Bay Ocean Outfall, the first use of an EPBM in North America. With the increased use of pressure face TBMs most consulting over the last 25 years has been in this area of tunneling. Noteworthy projects include Portland East Side and Westside CSOs, Port of Miami, Lake Mead Intake No.3, the SR-99 highway tunnel in Seattle, and Metro Vancouver’s water tunnel projects for seismic upgrade. Gregg Korbin has served on more than 60 technical and dispute resolution boards over the last 45 years.

Lecture presented in Burnaby, BC, Canada on April 13, 2023. Video recorded and published with permission from Gregg Korbin.

YouTube Video Description