SR-99 / Alaska Way Tunnel Project - Permanent Power - Seattle
In summer 2013, the world’s largest-diameter tunneling machine will begin a historic journey beneath downtown Seattle. Its purpose is to dig a tunnel to replace the SR 99 Alaskan Way Viaduct, a double-deck highway that has spanned the downtown waterfront for more than half a century.
The project includes:
• A two-mile-long tunnel beneath downtown Seattle.
• A mile-long stretch of new highway that connects to the south entrance of the tunnel, near Seattle’s stadiums.
• A new overpass at the south end of downtown that allows traffic to bypass train blockages near Seattle’s busiest port terminal.
• Demolition of the viaduct’s downtown waterfront section in 2016.
• A new Alaskan Way surface street along the waterfront that connects SR 99 to downtown.
• Redundant electrical power system feeding each end of the tunnel and a tie circuit connecting both ends.
Click here for more information about this project.
PowerStudies, Inc was hired by the lead electrical engineering design firm to provide engineering design support by performing power system studies for the tunnel permanent power distribution system. PowerStudies, Inc engineers performed the following studies:
Duct bank ampacity (for relocation of Seattle City Light circuits)