Moving the Historic Washington Street Boat Landing

Washington Street Boat Landing removal process — Steel beams are installed to temporarily support the structure.

The Washington Street Boat Landing pergola is in the process of being removed, protected, and restored in anticipation of the Elliott Bay Seawall project. The move is slated for Sunday, February 9th and Monday, February 10th.

The historic boat landing’s iron shelter was built in 1920, and is one of three pergolas in Pioneer Square. The Pioneer Square Preservation Board gave its Certificate of Approval to move the structure to a storage site on Terminal 25, thereby ensuring its safety during construction. After the Seawall Project is completed, the pergola will be moved back to its original site and will be restored. Overseeing the project is the Seattle Department of Transportation (SDOT) under Section 106 MOA agreements.

From supervising project manager, Jessica Murphy, PE with SDOT: “Preparations for the relocation have been ongoing since early January 2014. Bracing of pergola walls, removal of the roof, lead abatement and other preparatory work has been performed under the oversight of Ron Wright, our architectural specialist. We are now in the final stages of preparation for the structure relocation to a site at Terminal 25. The move will happen in two steps: 1) The move eastward off the current pier structure, and 2) The final move south to Terminal 25.”

Steps have been taken to ensure restoration of the pergola will be historically accurate. Under the Section 106 MOA rules, a rigorous documenting process has been put in place and organizers are actively photographing and video recording every part of the structure that is removed.

This move and plans for restoration could not have come any sooner! In September 2012, the Alliance for Pioneer Square contacted SDOT about signs of deterioration on the historic boat landing. We look forward to see it renewed on a world class waterfront in the near future.

Alaskan Way Viaduct Replacement Project Construction Update – January 2014

Progress made in search for tunnel blockage

It was a busy holiday season for crews working to get Bertha, the SR 99 tunneling machine, digging again. While we still can’t say for sure what halted the machine on Dec. 6, we’re much closer to finding an answer than we were when all of this started.

Here’s a recap of what crews have been up to since the blockage occurred:

On Dec. 7, our contractor, Seattle Tunnel Partners (STP), began prepping the machine and surrounding environment so crews could inspect the cutterhead and excavation chamber safely.
On Dec. 17, a brief visual inspection of a small section of the excavation chamber and cutterhead found dirt, sand and cobbles – nothing unusual.
Over the holidays, STP crews were on-site to drill dewatering wells, maintain the machine and switch out cutting tools on the machine’s face.
Earlier this week, STP drilled 17 small-diameter, exploratory holes near the front of the machine to see if they could identify an obstruction. They encountered obstructions in four of the holes.
On Jan. 2, the water pressure was low enough and enough soil was removed from the excavation chamber to inspect the top 15 feet of the chamber.
This inspection showed an 8-inch-diameter steel pipe protruding through one of the many openings in the cutterhead. We believe the steel pipe is a well casing installed by WSDOT in 2002 after the 2001 Nisqually earthquake to better understand how groundwater flows through this area. The location of this pipe was included in reference materials in the contract.
We also believe at least some of the obstructions found by the exploratory holes are pieces of the 2002 steel pipe, which could be a contributing factor in the delay of boring.
Other potential factors include changing soil conditions that may have caused excessive wear of cutting tools, potential objects in front of the cutterhead or objects in the lower portion of the excavation chamber that still aren’t visible.

Next steps

STP is considering several options to remove the steel pipe and identify other potential obstructions.

While Bertha is stopped, other work is taking place. This includes:

Extensive construction on the north and south ends of the tunnel.
Preparatory work to dismantle the push frame and temporary tunnel rings in the launch pit.
Preparatory work to reconfigure the launch pitand build the roadway within the tunnel.

It’s too early to speculate about the cost or long-term schedule implications of this issue. We’ll continue to work with STP to determine ways to make up time lost during the blockage. Our focus is now on addressing this issue safely and in a timely manner so we can resume tunneling as soon as possible.

Watch the Alaskan Way Viaduct Replacement Project on YouTube

The Washington State Department of Transportation has a YouTube channel dedicated to the big construction project that has dominated the Seattle Waterfront for the past couple of years. Here you’ll find animated videos of how Bertha the world’s largest tunnel boring machine works, loving goodbyes to the old viaduct which the new tunnel will replace, and milestones throughout the project. Above is a video showing Mario driving a go-cart through a simulation WSDOT originally posted of a temporary route for SR 99.

As we’re learning about what’s really blocking Bertha the Tunnel Boring Machine, you may want to get caught up on what Bertha is doing underneath Pioneer Square and why she’s digging a 2-mile tunnel underneath Downtown Seattle. Visit Milepost 31, the information center dedicated to the area’s history and the technology used in the tunnel boring machine. It’s located in Pioneer Square and tours of the nearby launch site are held regularly, as well as a Speaker Series on First Thursdays. There’s also a fabulous historical website called ViaductHistory.com through which visitors can explore the history of the SR 99 viaduct and surrounding neighborhoods. You can even follow Bertha on Twitter!