Dec. 9 project update

Posted on Dec 9 2014 2:51 PM
Excavation continues on the circular pit (pdf 2.5 Mb) that will be used to access and repair the SR 99 tunneling machine. Seattle Tunnel Partners’ engineers have determined that continuing excavation to 84 feet, an additional 3 feet from the current depth, will not affect when and how the dewatering wells could be turned off. We anticipate excavation to this elevation will take approximately one day, at which time STP will inspect the shaft walls per their quality assurance procedures. Once they reach 84 feet, STP will review survey data and consult with their engineers and WSDOT prior to determining next steps.
Access pit
The modular lift tower, or large crane that will lift the front end of the tunneling machine to the surface, is taking shape near the access pit. Below is a photo that was taken today from access pit camera #1. Crews recently started to erect the modular lift tower support legs.
Modular Lift Tower
Inside the tunnel, crews continue to build the interior roadway walls. Below you can see a truck pumping concrete into the wall forms. Crews are continuing to work on the first 450 feet of interior structures.
Tunnel walls