Seattle Sound Transit is seeking bids for its Northgate Link Light Rail Extension, TBM Tunnels contract (N125). The project consists of 3.48 miles of twin-bored, 22-ft outside diameter tunnels that run from the Maple Leaf Portal in the Northgate suburb of Seattle to Sound Transit’s University of Washington Station near Husky Stadium. The project has 23 cross passages that connect the running tunnels. In addition, the contract also contains work to install support of excavation systems and excavation for two underground stations, one in the University District and one in the Roosevelt neighborhood. The station finishes will be built under separate contracts. The U District station support of excavation consists of soldier piles and lagging, soil nails, secant piles and tie backs. The Roosevelt station support of excavation is designed to use secant piles with tie backs.
Currently, the design for this project is 100 percent complete and is under final review. The project is expected to be advertised for bids in the second quarter of 2013. Notice to Proceed for the N125 contract is expected in the fourth quarter of 2013. Sound Transit’s Northgate Link Extension Principal Construction Manager will be Jonathan Gabelein (firstname.lastname@example.org).