(Photos and video by WSB’s Christopher Boffoli unless otherwise credited)

Not far from the most recognizable above-ground Seattle icon, the Highway 99 tunneling machine finished its 9,270-foot journey under watchful eyes this morning, as shown in our as-it-happened report earlier.

Photojournalist Christopher Boffoli was there for WSB and put together these video highlights:

If you noticed the drone – that was operated by WSDOT, which has since published this minute-long highlight reel:

So – now what? First: The tunneling machine, which arrived in pieces four years ago, will be taken away in pieces. After the cutterhead’s appearance this morning, removal of the braces began.

WSDOT elaborates on what’s ahead:

STP will disassemble the machine by cutting it into pieces. The pieces will be removed from the pit by crane and placed on trucks. Due to roadway restrictions, each truckload will weigh no more than 20 tons.

Some pieces of the machine may be reused on other tunneling projects, while others will be recycled. Because the machine is so large, removing it will likely take several months.

And then there’s a lot of work to be done inside the tunnel – digging it, and “building rings” along the way, was just the groundwork. This WSDOT post goes into details of what happens inside, from road-building to systems installation to testing and commissioning.

Once the tunnel is tied into the surface network, as recapped in the Viaduct/Tunnel FAQ (and discussed in WSB comments), here’s how Highway 99 is planned to connect to the south end of downtown:

Outside the tunnel, other matters remain unsettled. A big one: How much will the toll be? $1-vicinity recommendations were made three years ago. The Washington State Transportation Commission is charged with determining the final toll but there’s no date set for a vote yet. And of course you’ve heard a lot about court fights over cost overruns, mentioned again today in Seattle Times transportation reporter Mike Lindblom‘s look at what’s ahead. (Asked today about the cost overruns, Gov. Inslee said, ““There will be other days to talk about paying for this. We know that our State is going to be insistent that the contractor be financially responsible for the project. We have to get that resolved. I know that will be resolved. And I think there is reason for confidence that the State is going to be held harmless here.” Mayor Murray, asked about a legislator’s proposal to require the city to cover those costs, said today, ” I know we have our annual ‘Let’s bash Seattle’ down in Olympia every legislative session. But again it is a State project and the State will make sure it gets paid. And we will pay for the brand new park that will knit Seattle back to its waterfront.”)

Once the tunnel is open – that clears the way for the remainder of the Alaskan Way Viaduct, which opened 64 years ago today, to be torn down. It’s been more than five years since the south mile was demolished.

11:06 AM: Now that WSDOT says Bertha the tunneling machine is in the final foot before breakthrough, we are going to do what everybody else is doing and put up the live stream. What we’re hearing from those on scene: It’s dusty. Very dusty. More to come. (And if you just want to check back later to see how it all came out, so to speak, Christopher Boffoli is there for WSB and we’ll have pics from him.) If you use Twitter, watching tweets with the hashtag #BerthaBreakthrough is a mix of commentary, observations, humor, and memories (WSDOT notes that today is the Alaskan Way Viaduct’s 64th birthday).

11:28 AM: Christopher sends this view of what it looks like where he and other media are right now.

The site was opened to media about two hours ago. And now as we type this – it just happened:

11:35 AM: Pic from Christopher at the pit:

WSDOT has said it’ll take “weeks” before the machine is in its final position in the pit, to be broken down and hauled away in pieces … which is how it arrived, four years ago, via ship from Japan.

12:07 PM: Just in from Christopher, a new, clear view as the cutterhead continues its slow breakthrough:

And here’s the official news release just sent by WSDOT:

A year ago, SR 99 tunnel crews were about to face their biggest challenge: a trip beneath the Alaskan Way Viaduct they were working to replace. Today, with the viaduct and more than 9,270 feet of new tunnel safely behind them, there was nothing left to face but daylight as the SR 99 tunneling machine chewed its way into a pit near Seattle Center.

Bertha’s 1.7-mile drive beneath Seattle came to a successful end Tuesday afternoon, 64 years to the day since the viaduct first opened to traffic. Led by the Washington State Department of Transportation, and designed and built by contractor Seattle Tunnel Partners, the tunnel project will move a two-mile section of SR 99 underground when it wraps up in early 2019. Crews will then demolish the viaduct, clearing the way for the city’s new waterfront.

“This is a historic moment in our state’s transportation history,” Gov. Jay Inslee said. “Innovation and perseverance are the engines that keep Washington in the forefront. There is still more work ahead but this moment is one worth celebrating.”

Crews will spend the next several days removing steel support braces that stand between Bertha and the interior of the 90-foot-deep disassembly pit. When the braces are gone, crews will drive the machine into its final position and begin cutting it into pieces for removal. As owner of the machine, the contractor will determine which pieces could be salvaged for use on other projects or recycled.

“We were always confident that we would successfully complete the tunnel drive,” Seattle Tunnel Partners Project Manager Chris Dixon said. “The dedication and commitment of everyone on the Seattle Tunnel Partners team has been exceptional, and we wouldn’t be at this milestone without the hard work of our crews. We look forward to continuing this outstanding progress through project completion.”

STP still has significant work to complete before the tunnel opens. Crews must finish building the double-deck highway within the circular walls that were built by crews inside the tunneling machine. Mechanical and electrical systems, plumbing and safety features also must be installed.

Even as crews are installing these systems, crews will begin the extensive task of testing and commissioning the tunnel to ensure it’s ready for traffic. Inspectors will individually test more than 8,500 separate components before testing each of the tunnel’s various systems as a whole.

“This truly is a remarkable feat of engineering,” Transportation Secretary Roger Millar said. “There’s still work to be done, but the individuals working on this job should be proud of this accomplishment.”

Over the next several years, the City of Seattle’s Waterfront Seattle project will build new public space and a surface boulevard in the place of the double-deck viaduct, which is scheduled for demolition in 2019.

“Today is a major construction milestone in our plan to reclaim Seattle’s waterfront,” Seattle Mayor Ed Murray said. “We are one step closer to taking down the viaduct to make way for a reimagined waterfront and surrounding downtown neighborhood. We will build a waterfront for pedestrians, transit and sensible car trips without a freeway wall casting a shadow over our vision of a well-connected 21st century city.”

King County Metro will continue to rely on SR 99 to route buses to Seattle after the tunnel opens, said King County Executive Dow Constantine.

“The new tunnel will provide fast, reliable travel for transit and freight past downtown traffic, and reunite the city with its waterfront,” said Constantine. “The breakthrough highlights what we can accomplish when we think big, act boldly, and embrace the ‘can-do’ tradition of our region.”

Port of Seattle Commission Commissioner Courtney Gregoire said the tunnel will work with the new waterfront surface street to accommodate freight traffic.

“This Alaskan Way route is essential to a strong port and linking our industrial lands between SODO and Ballard,” Gregoire said. “Strong, vibrant transportation connections are essential to keep our economy growing and creating middle-class jobs.”

Background on tunneling machine repairs

Manufactured in Japan by Hitachi Zosen Corp., Bertha arrived in Seattle in April 2013. The machine was launched from a pit near the stadiums in July of that year. In December 2013, STP stopped mining after measuring increased temperatures in the machine.

After an investigation, STP discovered damage to the machine’s main bearing. Crews completed repairs and resumed mining in December 2015. The cause of damage to the tunneling machine is in dispute and is currently in litigation. Neither WSDOT nor STP is able to comment further on ongoing legal issues.

1:37 PM: Just in case you were wondering, the machine’s movement is done for the day, by the way, Christopher and other media at the scene were told.

4:08 PM: Pending our “what’s next” second wrapup later today, here’s Christopher’s video of highlights from the breakthrough and the comments afterward, including the governor, mayor, county executive, and others:

More later. WSDOT, meantime, says the livestream camera will be up until 9 tomorrow morning.

(Image from disassembly-pit camera tonight)

Four years and two days after the Highway 99 tunneling machine arrived in Seattle, in pieces, after a trans-Pacific trip from Japan, it’s scheduled to finish its part of the tunnel-building job tomorrow. WSDOT announced this afternoon that the machine is on the brink of “breakthrough”:

Crews will spend this evening making final preparations. Then, early tomorrow, the massive machine will begin mining through the wall and into the pit where it will be disassembled. Machine operators will proceed slowly through the wall, so it may take several hours for the cutterhead to emerge.

And even once it does, it won’t be done, as WSDOT’s update explains – “it will be weeks until the machine is in its final position in the disassembly pit.” Then, it will be broken apart to be removed from the pit. Live-stream and time-lapse cameras are already embedded on the “Follow Bertha” page, since the public isn’t allowed at the construction site to watch in person. The latest advisory from WSDOT suggests this will happen no sooner than midmorning, but timing is subject to change – the project Twitter account is a good place to watch for updates (and we’ll be tracking it here on WSB too).

Breakthrough will come on the north side of downtown, at the end of a 9,270-foot tunnel route along which there’s still road-building and other work to be done before the tunnel’s projected opening in early 2019 (here’s the newest progress report).