North End

North End

Last updated March 1, 2016

Sign foundation work on SR 99/Aurora Avenue North complete (for now) 

Crews have finished installing concrete foundations for new overhead traffic signs on SR 99/Aurora Avenue North. Located between the Aurora Bridge and just north of Mercer Street, these traffic signs will communicate important information to drivers approaching the future SR 99 tunnel – similar to the large signs on I-5 and other highways. 
Crews finished foundation work near Comstock Street on Tuesday morning, March 1. The project began in mid-January and required lane reductions along this section of Aurora. Thank you for your patience and flexibility as we completed this work. 
Minor electrical work continues 
Electrical crews will continue working for one to two more weeks to install underground electrical cabinets and connect communications lines to the overhead system. This work will continue to intermittently close one southbound lane at Valley Street and Raye Street during off-peak hours only.
Future lane closures on SR 99 
This spring crews will return to SR 99 to erect the metal sign structures at each of the new foundations (the actual signs will be hung at a later date). Because of the size of the structures and the equipment needed, this work will require partial or full directional closures on SR 99. We will notify the traveling public of expected traffic impacts once this work is scheduled. 
For questions or concerns about SR 99 lane closures, contact us at or 1-888-AWV-LINE (298-5463). 

Originally posted Dec. 7, 2015.

Building the north portal

A significant amount of construction continues at the SR 99 tunnel’s future north portal. This is the spot where Bertha, the SR 99 tunneling machine, will emerge at the end of her two-mile journey beneath downtown Seattle. 

Enlarging the image below will display a rendering of the way the future SR 99 will connect with the surrounding surface streets. 

North portal progress 

Seattle Tunnel Partners continues to build the tunnel's future north portal. Here's a shot of the pit where Bertha will complete her journey. You can see the future lanes of the SR 99 tunnel with northbound lanes on the bottom of the image and the southbound lanes and a ventilation corridor above them. 

North operations building construction

STP crews near the receiving pit are hard at work on the north operations building. Crews installed the building's yellow ventilation stacks in July. This post explains the tunnel's two operations buildings in more detail.

Future north portal connections

Crews working for Atkinson Construction are building the walls and roadbed for the future northbound lanes that will come out of the north end of the SR 99 tunnel. The opening just below the Space Needle is the future tunnel portal for southbound traffic.