Composite Waterproofing System Embraces Redundancy for Enhanced Performance
University Link Light Rail (U-Link) is an extension to the north of the Sound Transit Link light rail system in Seattle. When completed, the 3.15-mile light rail extension will run in twin-bored tunnels, bringing the region’s light rail system total to more than 19 miles. The tunnel requires a permanent waterproofing system to protect structures, electrical equipment, people, etc. The U-250 is about 100 feet underground with three station entrances and connections to the University of Washington campus by pedestrian bridge. Cooley Group manufactured the membranes and worked with BDA Associates and SPS Infrastructure Inc. to waterproof the Husky Stadium station segment of this project.
With underground stations at Capitol Hill and at the University of Washington’s Husky Stadium, the U-Link will serve the three largest urban centers in the state of Washington — downtown Seattle, Capitol Hill and the University District. The high-speed, high-capacity, congestion-free light rail originates at the Westlake station in downtown Seattle, continuing under First and Capitol Hill then under the Montlake Cut, and ending at the stadium beneath what is now surface parking lot E11. The footprint of the station is 780 feet long and 58 feet wide with a 32-foot wide station platform located 90 feet below grade. The addition of this one station is expected to add 71,000 riders to the system by 2030, bringing the system-wide total to 114,000.