By Lynn Peterson

What a summer.

Wildfires, flash floods, tornados. Our state has faced no shortage of unplanned challenges recently. In addition to causing more serious repercussions, these challenges strain our transportation system, particularly when they hit during a busy season of planned construction closures. Add it all up and you end up with a predictable outcome: delays and frustration for travelers trying to reach their destination.

New SR 99 at Broad Street

Today, as scheduled, we wrapped up a four-day closure of State Route 99 in Seattle that included two rare weekday closures of the highway. Before the closure started, we asked you to do your part to help. We suggested you plan ahead, change your travel mode or revise your commute, among other measures aimed at reducing congestion. As you did during major lane reductions on I-90 last month, you delivered. Traffic was more challenging than usual, but we expected that. And had you not heeded our suggestions, things would have been much, much worse.

Progress

Of course when you’re sitting in traffic, it’s easy to forget that the headaches we’re enduring have tangible benefits. In the case of the four-day SR 99 closure, we came away with plenty to show.

Most notably, crews building the future north portal of the SR 99 tunnel demolished and replaced the section of SR 99 that crosses above Broad Street in Seattle. It looks easy in this time-lapse video, but completing this work and reopening the highway in four days was no small feat. 

During the weekend portion of the closure, crews replaced 81 concrete panels on SR 99 south of downtown, repaired an expansion joint at the Seneca Street off-ramp from northbound SR 99 and cleared ivy from the Alaskan Way Viaduct to make future maintenance of the structure easier.

With more than 18,000 miles of highway under our care, we’re always getting ready for the next big push. There will be more closures, more travel challenges. But please be assured that we spend a significant amount of time and energy coordinating our work in advance, and doing everything we can to minimize delays for the traveling public.

When the next big closure approaches, we’ll again ask for your help. Let me say in advance, on behalf of your fellow travelers, thank you. Your help, and your patience, benefit everyone as we work together to maintain and improve our state’s transportation system.

Keeping the Alaskan Way Viaduct safely open to traffic during SR 99 tunnel construction is a top priority. It’s one of the main reasons we’re boring a tunnel – to minimize disruption at the surface as we replace the viaduct.

Recent media reports have stated that ground settlement due to tunnel construction could cause us to close the viaduct. These reports are inaccurate.

The viaduct is still vulnerable to earthquakes, but it remains safe for everyday use. The viaduct settled as a result of the Nisqually earthquake and we strengthened the viaduct in those areas so it remains safe for drivers.

We have no plans to close the viaduct until after the tunnel opens to traffic. Crews inspect the structure four times per year – the next inspection is scheduled for this weekend – and have taken a number of steps to protect it during construction.

We anticipated some ground settlement would occur during construction of the tunnel, which is taking place near the viaduct. That is why the viaduct has been strengthened in this area and more than 100 monitors have been installed on the viaduct to measure how much the ground beneath the structure moves.

Those monitors told us that the viaduct settled up to four-tenths of an inch at one location along the viaduct near where tunnel construction is underway. This settlement is well within the limits established by WSDOT’s structural engineers.

We will continue to carefully monitor the viaduct during construction and will take additional steps to reinforce the viaduct if needed.

We’ll be posting additional details soon about the work we’ve done to protect the viaduct. In the meantime, please feel free to contact us if you have questions or concerns.

Learn more about the Alaskan Way Viaduct Replacement Program.

By guest blogger KaDeena Yerkan

This week a small group of WSDOT and Federal Highway Administration (FHWA) officials gathered in a conference room in downtown Seattle to watch something that will change the course of history in Seattle.

With little more fanfare than snapping a few photographs, FHWA’s Washington Division Administrator Dan Mathis, signed the SR 99 Alaskan Way Viaduct Replacement Project’s Record of Decision. While the document has a long and bureaucratic title, its intent is clear. It means that we have successfully completed 10 years of environmental review and can now focus on final design and construction of the new SR 99 tunnel beneath downtown Seattle.

Dan Mathis, FHWA’s Washington division administrator, preparing to sign the SR 99 Alaskan Way Viaduct Replacement Project’s Record of Decision with Secretary of Transportation Paula Hammond.

So, what is a record of decision? In a nutshell, it’s federal approval of a project’s environmental review, and it describes the project the agencies have decided to build. A record of decision also includes any mitigation measures and commitments the project will need to implement. For the SR 99 tunnel, this list includes monitoring buildings and utilities during tunnel boring, replacing lost parking during construction and keeping neighbors and the public informed throughout the project.

The signed document set in motion a flurry of activities to get tunnel construction started. One of the first things we did was give our tunnel contractor, Seattle Tunnel Partners, the official notice to proceed with final design and construction. Seattle Tunnel Partners, along with boring machine manufacturer Hitachi Zosen, will begin work this fall.  When it opens in late 2015, the 1.7-mile-long tunnel will whisk traffic between Seattle’s SODO and South Lake Union neighborhoods.

Once open, the tunnel will also allow us to remove the final stretch of double-deck viaduct along Seattle’s downtown waterfront. The Alaskan Way Viaduct is vulnerable to collapse in a severe earthquake, which is why we’ve been working so diligently to make its replacement a reality. A project to replace nearly half of the viaduct with a new above-ground roadway is already under way south of downtown and is designed to eventually connect to the tunnel.