(April 2, 2013, WSB photo by Nick Adams)

SUNDAY NIGHT: If you’re on Highway 99 tunnel watch – the tunneling machine is now down to a double-digit distance, 89 feet as of this morning. WSDOT still is not officially predicting what day will bring the “Bertha breakthrough,” but at this rate (it’s gone 38 feet since Friday), it’s likely to be this week. They’ve said that it will happen in two phases – the machine will reach the wall of the disassembly pit and stop, while WSDOT and Seattle Tunnel Partners explain what happens next. Then, likely on the following day, the machine will be set into motion for a several-hours-long breakthrough process. They continue to promise a live camera will be available, since the pit is in a construction zone and a public viewing area isn’t feasible.

P.S. Checking the archives, we note that today is the 4th anniversary of the tunneling machine’s arrival via ship from Japan.

MONDAY AFTERNOON: So much news today that we haven’t had time to publish an update yet, but WSDOT is expecting breakthrough sometime Tuesday – here’s the latest; full update a bit later.

(WSDOT photo)

If the Highway 99 tunneling machine keeps digging at the same pace of the past few days – 61 feet between yesterday’s update and today’s update, and 127 feet to go – next week could bring the breakthrough. Just a reminder that WSDOT and Seattle Tunnel Partners are NOT opening the site for the public to watch it happen, but they’re working on some kind of a live feed. Once the machine gets to the end of the line, it will be broken into pieces, which is why they’re calling what you see above “the disassembly pit.”

We’ve been watching the Highway 99 tunneling-machine update page, now that “Bertha” is getting close to breakthrough, and just noticed that today’s update says 219 feet to go – same as yesterday. WSDOT explains via Twitter that “(Seattle Tunnel Partners) is wrapping up routine maintenance and plans to resume mining tomorrow.” So for those who speculated breakthrough might happen this week – highly unlikely.

(WSDOT photo of ‘disassembly pit’ that accompanied today’s progress-report tweet)

The Highway 99 tunneling team has now moved from twice-weekly progress reports to daily progress reports. Not that the tunneling machine is on an “any day now” basis yet, but here’s what WSDOT reports this afternoon:

Seattle Tunnel Partners is making final preparations for the SR 99 tunneling machine’s arrival at the disassembly pit near Seattle Center. Because mining rates will continue to vary as crews approach the pit, we can’t predict when Bertha’s breakthrough will occur. We will continue to provide regular progress updates along the way.

We recognize that there is great interest surrounding this stage of the project, and we are working on ways to share this historic moment with the public. We will be activating a new time-lapse camera as well as streaming video of the disassembly pit prior to breakthrough. These cameras will offer the best view of Bertha’s arrival in the pit. We will also continue to share photos and provide frequent updates via social media, including daily progress updates. For safety reasons, the public will not be allowed in the construction zone during the breakthrough.

Look for more updates soon about the breakthrough sequence, the process for disassembling Bertha and the work that remains before the tunnel opens in 2019.

As of today, WSDOT tweeted, “Today Bertha has 320 feet to go – less than the Mariners 326′ right-field foul line in Safeco Field.” They’ve said that they won’t be setting up an in-person breakthrough-watching event because the pit is in the middle of a construction zone.

(WSDOT photo: Crews assembling rebar for a section of the foundation to support northbound SR 99 roadway and wall on west side of roadway)

The Highway 99 tunneling machine is back on the move, and re-aligned after veering a half-foot off course, according to this update late today from WSDOT:

Seattle Tunnel Partners resumed mining today after conducting additional survey work to verify Bertha’s position and to make necessary adjustments to complete the tunnel drive. Crews performed routine inspections and maintenance while mining was stopped, including the replacement of cutterhead tools.

As of this afternoon, Bertha was tunneling north toward the intersection of Denny Way and Sixth Avenue North, less than 1,000 feet from the disassembly pit.

STP stopped mining on February 28 after survey data indicated the tunneling machine may be several inches off the tunnel alignment. Three independent surveys confirmed the 57.5-foot machine was approximately six inches off alignment.

STP designers made a slight change to the tunnel alignment between the machine’s current location and the end of the tunnel drive. Adjustments are common during tunneling, including on this project. STP made a similar adjustment to correct Bertha’s course after the machine mined out of the access pit following repairs.

Crews steer Bertha based on information they receive from its on-board guidance system. The system is now set to the new tunnel alignment. According to STP’s most recent schedule, Bertha will arrive at the disassembly pit in May.

(WSDOT photo taken last month – work crews in the tunnel)

WSDOT says tonight that the Highway 99 tunneling machine is expected to arrive in its “disassembly pit” in May. That news comes as they also announce that Seattle Tunnel Partners has stopped digging to get the machine ready for the “final 1,000 feet of the 9,270-foot tunnel drive.” They’re checking its position because, WSDOT’s update says:

Recent surveys show that Bertha may be several inches off of the tunnel alignment. STP is conducting additional survey work and will make adjustments as needed to complete the tunnel drive.

Adjustments are common during tunneling, including on this project. STP made a similar adjustment to correct Bertha’s course after crews mined out of the pit that was used to access and repair the machine.

Crews will continue to perform routine maintenance on the machine for the next several days. They plan to resume mining next week.

According to STP’s most recent schedule, Bertha will arrive at the disassembly pit in May. The pit is located approximately 960 feet north of the cutterhead’s current location beneath Denny Way and Sixth Avenue North. Mining rates will continue to vary based on maintenance needs and soil conditions.

Crews successfully mined under the final building of the tunnel drive earlier this week. Bertha has traveled a total of 8,310 feet and built 1,270 of 1,426 concrete tunnel rings.

Because the end-of-the-line pit is part of a construction site, WSDOT has said it’s not planning to have a big event for the public to watch the machine break through.

Meantime, yet another reminder – the Alaskan Way Viaduct is scheduled to close for inspection 6 am-6 pm each day this Saturday and Sunday, with a few other events on 99 north of the Battery Street Tunnel – full details are here.

(Tunnel as seen from machine – WSDOT photo taken earlier this month)

Since the last twice-weekly update, the Highway 99 tunneling machine has passed the 8,000-foot mark of its 9,270-foot route. To be specific, as of today, it’s dug 8,132 feet and has 1,138 feet to go – about two more blocks, according to today’s WSDOT update. It’s currently near 6th/Wall and set to emerge at 6th/Thomas.

P.S. If you missed it earlier today, WSDOT has announced the Alaskan Way Viaduct’s next weekend maintenance (etc.) closure will be March 4-5.

Last weekend, we noted that the Highway 99 tunneling machine was in the zone where it would pass beneath the Battery Street Tunnel and the Seattle Center Monorail. This afternoon, WSDOT reported that it’s gone beneath the former and on its way to the latter. The machine is now 115 feet beneath the surface and climbing upward, 100 feet higher than the tunnel’s deepest point. WSDOT also reports that roadbuilding continues and is already halfway down the 7,692-foot path that’s been dug – here’s a document with updates on that and other parts of the project. WSDOT adds, “Work has also begun on the mechanical, electrical and plumbing systems within the tunnel. Crews began installing these systems near the stadiums last week …” Read today’s full tunneling update here.

Somebody asked us how the Highway 99 tunneling machine is doing. While WSDOT hasn’t had many major updates lately, it’s continuing the routine of publishing distance updates on this page on Mondays and Thursdays, and according to the newest number – 7,499 feet dug, of the 9,270-foot route – it’s now more than 80 percent of the way to the end. The zone it’s in now goes below the Battery Street Tunnel, which will be decommissioned when the new tunnel opens, and beneath the foundation of the Seattle Center-to-downtown Monorail.

WSDOT just published that new video about working hyperbarically with the Highway 99 tunneling machine as it continues a maintenance stop before moving on to dig the final 25 percent of its 9,270-foot path – explaining, among other machines, that the machine is underwater as well as underground and is therefore something of “a submarine.” During the maintenance work that’s been under way since January 5th, crews have replaced 250 cutterhead tools, like these:

See the latest tunnel update here; the machine’s current location is shown here.

(Map showing the zone where the tunneling machine is now, from WSDOT’s update page)

Among those taking time off for the holidays, the Highway 99 tunneling-machine crew. Here’s the last update of the year from WSDOT, with a bit more than one-fourth of the way to go on the tunnel route:

Seattle Tunnel Partners crews built their final concrete tunnel ring of the year on Tuesday before stopping for the holidays. The remaining days of 2016 will include a break for crews, followed by scheduled maintenance on Bertha, the SR 99 tunneling the machine.

In the year since STP restarted tunneling, Bertha has traveled approximately 5,700 feet and built almost 900 rings. Along the way, crews continued to control the ground as they mined beneath streets and structures, including the Alaskan Way Viaduct.

When mining resumes early in the new year, Bertha will be less than 2,500 feet from the pit near Seattle Center where she’ll emerge at the end of her journey. STP will continue to inspect and perform maintenance on the machine as needed.

Bertha’s cutterhead is located approximately 160 feet below Third Avenue between Blanchard and Bell streets. Progress updates are posted on Mondays and Thursdays at our Follow Bertha page. You can also follow Bertha on Twitter @BerthaDigsSR99.

Happy holidays from the Alaskan Way Viaduct Replacement Program. We’ll see you in 2017.

Current estimate is for the tunnel to open in early 2019. That’ll be almost a decade after the waterfront ceremony formalizing the plan; at that time, the hope was for a 2015 opening.

That time-lapse video shows road-building inside the under-construction Highway 99 tunnel, and it accompanies WSDOT’s latest update on tunneling progress. The tunneling machine is now more than 70 percent of the way along the 9,270-foot route, according to WSDOT, which included the video in this update published today. It’s the second update of the week – this one details progress at the tunnel’s “south portal.” It’s been almost a full year since tunneling resumed on December 22, 2015, two years and two weeks after the machine stalled.

While the Highway 99 tunneling machine hasn’t made much news lately, it’s continuing to dig steadily along, says WSDOT. Their latest twice-weekly update, published this afternoon, says it’s more than two-thirds of the way down the route – 6,337 of 9,270 feet. It’s already gone past the deepest point on the route and is starting to climb back toward the surface, currently in the zone beneath Belltown. The current estimated opening date remains early 2019, and as noted in this tweet, Viaduct demolition would follow over much of the rest of that year.

The Highway 99 tunneling machine has passed the one-mile mark as of this morning, according to WSDOT. It’s also made a new video showing how the machine is steered along its designated path underground, considering there’s no GPS:

The machine is at its deepest point – around 200 feet underground – with just under 4,000 feet remaining on the route, which is shown on this map, along with the machine’s approximate current location. The most recent timeline says that absent any further major problems, the tunnel will open in 2019.