Latest updates on the Alaskan Way Viaduct Replacement Program
With Bertha, the SR 99 tunneling machine, having safely reached her planned maintenance stop, Seattle Tunnel Partners is preparing to complete up to one month of planned maintenance. While the maintenance is routine, some of the methods crews will use to complete it are anything but. That’s because they’ll be performing some work in hyperbaric conditions as they get Bertha ready to tunnel beneath the Alaskan Way Viaduct and downtown.
Hyperbaric conditions are those … more
Seattle is prone to earthquakes, so it’s not surprising that one of the most common questions we receive is this: Will the tunnel be safe in an earthquake?
All modern structures in the area – including bridges and highways – must be designed with earthquake safety in mind. But geotechnical and structural engineers agree that tunnels are among the safest places to be during an earthquake.
Some folks find this counterintuitive. How is it safe to be … more
Last week we reported that crews were making good progress as they worked to install sign foundations on SR 99/Aurora Avenue North in Seattle. Turns out good progress leads to good news: the first phase of sign foundation work is finishing ahead of schedule. By Friday afternoon, median lane closures should be removed and the southbound bus-only lane will be restored to normal operations.
It may be tough to tell, but the new foundations for each sign on SR 99 extend 14 to 18 feet … more
If you’re a regular user of SR 99/Aurora Avenue North between the Aurora Bridge and just north of Mercer Street, we’d like to thank you for doing your part to help keep traffic delays to a minimum during the past two weeks.
Crews are around the halfway mark for the first phase of sign foundation installation work happening on this stretch of SR 99 and are pleased with the progress they’ve made. Work is continuing on schedule and crews expect to move into the … more
We’re quickly nearing some major lane closures in both directions of SR 99/Aurora Avenue heading into and out of downtown Seattle. Starting Jan. 18 and continuing for several weeks, drivers and bus riders should expect slower commutes and some challenging traffic, which is never welcome news. Why these particular closures now? Please read on.
What is closing?
The inside lane in each direction of Aurora Avenue North between the Aurora Bridge and just north of … more
For being Seattle’s “most boring” exhibit, Milepost 31 sure is popular. December marks the four-year anniversary of the information center, which blends information about the SR 99 Tunnel Project with the history of Seattle’s Pioneer Square neighborhood. In addition to recently welcoming the center’s 50,000th visitor, Milepost 31 staff have led hundreds of tours to see SR 99 tunnel construction, and hosted educational programs for school groups and youth … more
As walls are installed at the north and south portal operations buildings in the coming weeks, drivers may be surprised by how little their view inside the buildings changes. The exterior walls of the large fan rooms will be made of glass, providing passersby with a glimpse of the everyday activities that will occur inside these important operation centers.
The decision to use glass walls arose out of the guiding principles for the operations buildings: to reflect their function and … more
Protecting taxpayers is a top priority as we replace the Alaskan Way Viaduct. An important tool in this effort is our design-build contract with Seattle Tunnel Partners, which places a greater share of project risk on the contractor by requiring them to design and build the tunnel.
Another protective measure is insurance, which the contract requires STP to have. Both STP and WSDOT are named on the project’s insurance policy, and both entities have the right to make insurance … more
Future connections between the SR 99 tunnel and city streets are continuing to take shape at the south portal, even if they're only partially visible from the surface. Drivers passing overhead didn't know it, but Seattle Tunnel Partners recently demolished a temporary wall separating the future mainline section of the tunnel from the on-ramp that will one day allow travelers to access northbound SR 99 from the stadiums.
The first photo shows the view from inside the cut-and-cover … more
This weekend, crews will shift State Route 99/Aurora Avenue traffic onto new lanes through the construction zone at the SR 99 tunnel's future north portal. For drivers, a traffic shift is a change in the route one takes to get to work, events or a game. For road builders, a traffic shift is a way to mark the next step toward project completion.
In this latest traffic shift, the progress is significant – 750 feet of new roadway that will be part of the permanent … more