No. 3 - Alaskan Way Viaduct Replacement Tunnel Project

No. 3 - Alaskan Way Viaduct Replacement Tunnel Project

Before most grand openings like this, customers are at least allowed to pass along in a line and look at the goods.

The Alaskan Way Viaduct Replacement Project will use the more traditional methods before the ribbon cutting. Everyone will have to stay off the property while just the workers mill about doing last-minute tasks. The longest highway closure in Puget Sound history will be required before traffic can experience the S.R. 99 tunnel. It will take three weeks of no traffic while crews connect road segments of S.R. 99 to the massive two-level traffic cylinder. Road projects usually consist of a work zone alongside moving traffic. Very few involve complete road closures.

In mid-September officials announced the opening would be during the first quarter of 2019, even though the hope was for the moment to happen in late 2018.

The following factors influenced the decision:

Construction progress: The Washington State DOT (WSDOT) has several contractors that must complete work to be ready for the three-week S.R. 99 closure. Scarsella Brothers Inc. will then build the final tunnel and ramp connections. Some of this work, like road striping, is weather dependent;

Public notice: Starting in January ensures that contractor work will be complete and a specific opening date will be provided well in advance;

Holiday travel and commerce: WSDOT and its partner agencies are committed to keeping people and goods moving during the busy holiday season. Avoiding a major highway closure between Thanksgiving and New Year’s Day helps achieve this goal. There also are fewer major events in early 2019 than there are during the last quarter of 2018.

The three-week road closure will start on Jan. 11.

“We have a big ask . . . we want drivers to change their commutes and driving habits for three weeks and there are 90,000 vehicles a day that use the viaduct,” Laura Newborn, spokesperson for the Washington State DOT, told Roads & Bridges. “We know from past closures of S.R. 99 that all highways through the region see increased traffic.”

When Roads & Bridges last checked in on progress on the S.R. 99 tunnel project back in July the prime contractor, Seattle Tunnel Partners, was in the middle of doing extensive testing on the systems inside the tunnel. At press time for the October issue, testing was close to 80% complete.

Newborn also said Scarsella Brothers was working on installing bridge work signage and road work needed in advance of the three-week S.R. 99 closure. Kiewit Infrastructure West Co. was completing the work needed to move Alaskan Way out from underneath the viaduct. The traffic switch was expected to take place in October and will provide two lanes of traffic in each direction for travelers along Seattle’s waterfront.

Location: Seattle, Wash.

Owner: Washington State DOT

Designer: HNTB Corp.

Contractor: Seattle Tunnel Partners

Cost: $3.3 billion

Length: 2 miles (tunnel)

Completion Date: Early 2019