Latest updates on the Alaskan Way Viaduct Replacement Program
Over the weekend, crews closed State Route 99 through downtown Seattle for an important reason: the South Atlantic Street overpass needed space to emerge from its cocoon. Don’t worry, it wasn’t flying anywhere. And it isn’t nearly as colorful as a butterfly. Still, you’ll notice a huge difference the next time you take SR 99 through SODO.
For nearly a year, hundreds of steel and timber beams, and acres of plywood and foam spanned the highway in roughly the same … more
Seattleites were digging tunnels long before Bertha, the SR 99 tunneling machine, came along. Folks started transforming subterranean Seattle in 1894, with construction of a sewer tunnel not far from the SR 99 tunnel’s north portal construction site. Since then the city has seen – or not seen, as the case may be – construction of more than 40 miles worth of tunnels.
Last month marked the 109th anniversary of the historic breakthrough on the Great Northern Tunnel, which … more
Saturday, Oct. 19, marks the 145th birthday of Bertha Knight Landes, after whom the SR 99 tunneling machine was named.
Ms. Landes didn’t dig any tunnels, but there’s no question she broke ground. Elected mayor of Seattle in 1926, she was the first woman to lead a major American city. During her two years in office she battled bootleggers, cleaned up corruption in city government and put the city’s finances in order.
She was active outside of politics, too, playing … more
Bertha, the SR 99 tunneling machine, has passed the 200-foot mark as she continues her dig toward the north end of downtown Seattle.
By the end of her shift on Oct. 8, Bertha had traveled a total of 209 feet and the top of her cutterhead was about 20 feet below the surface. She averaged nearly 14 feet of digging per day over the past week.
Bertha is still making her way through fill soil that crews have injected with grout to provide additional strength. She’ll pass into … more
It was a good first week back on the job for Bertha, the SR 99 tunneling machine.
Bertha dug 64 feet between Sept. 23 and the end of the month, averaging about 11 feet of excavation per work day. Add that to the 24 feet she traveled prior to the monthlong stoppage in mining, and Bertha had traveled a total of 88 feet by the start of October.
The end of September brought with it an important milestone: installation of the first permanent tunnel ring. Now that Bertha is building rings … more
More than 1,000 feet of soil separates Bertha from the spot where she’ll pass beneath the Alaskan Way Viaduct a few months from now. That gives drivers plenty of time to prepare for Bertha’s big crossing, which will require an extended around-the-clock closure of the viaduct.
Crews will close the viaduct for one to two weeks to allow Bertha to tunnel beneath the structure (pdf 913 kb). The machine could reach the viaduct in early 2014, but a specific date for the … more
Time-lapse video highlights the hard work that led up to Bertha’s July 30 launch
A lot can happen in two years. Just ask Bertha, the SR 99 tunneling machine.
Two years ago this week, Bertha existed only on paper and her launch-pit site was little more than a field of dirt where the south end of the viaduct once stood. Our contractor, Seattle Tunnel Partners, had just received the go-ahead to complete final design and begin building the SR 99 tunnel.
Then this … more
After slogging through 15 feet of concrete, Bertha gets a taste of the good stuff – but why did it take so long?
Engineers depend on math. It is the thing that, more than any building material, gives shape to their designs. Want proof that what you’re building matches the design? Check the plans, do the math.
But when it comes to tracking the progress of Bertha, the SR 99 tunneling machine, you can’t rely on an equation. Yes, we told you that Bertha would average 6 … more
This time, there were no crowds or fanfare. It was just Bertha, the world’s largest tunneling machine, finally getting the chance to do what she was built to do: dig.
Bertha got her first taste of tunneling on July 30, officially starting the 2-mile journey beneath downtown. Early Tuesday afternoon, Bertha’s 5-story-tall cutterhead broke through the north wall of her 80-foot-deep launch pit. She’s expected to emerge in about 14 months near the intersection of Sixth … more
Start with some sun, soil and celebration. Then add Bertha, the massive machine that will dig the SR 99 tunnel beneath downtown Seattle, and 5,000 of her closest friends. The result is a party big enough for the biggest tunnel-builder the world has ever seen.
Thousands of people descended on the SR 99 tunnel launch pit on Saturday for a chance to see Bertha up-close before she starts tunneling later this month. Guests talked to project staff, learned about the project and walked around … more