Seattle tunnel construction avoided costly mistakes of Boston's Big Dig

King 5 News ^ | January 17, 2019 | Amanda Grace

[Tolerance Sucks Rocks]

Seattle and Boston have a lot in common: they are both cities on the water, homes to higher learning institutions and hubs for tech companies. They are connected by Interstate 90 and memories of a Superbowl both cities can’t forget. Now Seattle and Boston are both home to big tunnels that run under the downtown core.

Seattle’s tunnel will now face a new challenge: avoiding the problems that plagued Boston’s Big Dig long after it opened.

The Big Dig Backstory

The Big Dig began as a project to replace the Central Artery, an elevated 6-lane highway that was structurally unsound and horribly congested. The state of Massachusetts decided to build an 8-to-10 lane underground expressway, a system of tunnels and four major highway interchanges. However, costs and the construction schedule ballooned out of control.

When Seattle was planning the Highway 99 tunnel, Boston’s troubled Big Dig represented everything that could go wrong. Opponents rallied against the Seattle tunnel, holding signs reading, “No Big Dig.”

In 2009, then-Washington Governor Christine Gregoire vowed to investigate what went wrong in Boston and make sure that any and every lesson that can be learned would be learned.

Seattle Tunnel vs. Big Dig

Infrastructure experts point out that construction was different on the two tunnels.

"Seattle had the benefit of not having an 8-lane super highway that it had to bury,” says Dan McNichol, a former Big Dig spokesperson who has written books about Boston’s tunnels. He says, in terms of scale, the Big Dig was the equivalent of burying I-5.

McNichol points out that Seattle chose a different construction method: tunnel boring versus cut-and-cover.

"The Big Dig was much shallower; therefore, the whole city was ripped up. They call that kind of construction cut and cover,” he explains . . .

[rockrr]

Seattle had the benefit of not having an 8-lane super highway that it had to bury,” says Dan McNichol...

Liar. The viaduct was 8-lanes. They just built a 4 lane tunnel to replace it. Actually being able to get around be damned!

[Steely Tom]

The mistakes of Boston’s Big Dig didn’t start to show up until the it had been open for four years, when a 24-ton chunk of ceiling fell on top of a car and killed someone.

The Seattle project hasn’t yet been open three weeks. Let’s wait and see a little bit before we declare it a thumping success.

[outofsalt]

Did they ever get the tunnel boring machine unstuck? It was disabled 1000 feet in the dig site for years, if memory serves.

[llevrok]

KING5 News (the most liberal of the 4 major stations in the area) fails to mention this tunnel is 3 years late and is $223 million over budget.

But when it’s not the government’s money, why report it?

[Seaplaner]

Why didn’t they just build a Bullet Train, like the one that’s working so well in California?

[Vlad The Inhaler]

They can thank labor unions and crooked politicians for the BIG DIG boondoggle.

BIG DIG original estimate - $2.4 Billion

BIG DIG final cost - $21 to $24 billion (cost plus interest)

https://www.boston.com/uncategorized/noprimarytagmatch/2012/07/10/true-cost-of-big-dig-exceeds-24-billion-with-interest-officials-determine

[Afterguard]

Isn’t this the Seattle tunnel project that they had the tunnel borer stuck in the hole for about a year +, and an extra 1$M or $2M over-run to get it out? Lol!

[Mears]

“BIG DIG final cost - $21 to $24 billion (cost plus interest)”

—

It did do wonders for the waterfront area,though.

:-)

.

[Moonman62]

Work was halted on December 6, 2013 after the machine overheated and shut down [70] approximately 1,083 feet (330 m) into the planned 9,270-foot-long (2,830 m) route. Investigations later revealed the seal system that protects the machine’s main bearing had been damaged. Three days prior to stopping, the machine mined through an 8-inch-steel well-casing used to help measure groundwater in 2002 around Alaskan Way, drilled as part of the planning phases of the project.[71] Whether this pipe had anything to do with the machine’s failure is at the center of legal dispute between WSDOT and the contractor, Seattle Tunnel Partners.[72] This delay lasted for more than two years as the workers had to dig a 120-foot (37 m) vertical shaft down to Bertha’s cutting head to repair it. Settling was discovered in Pioneer Square that may be related to this additional excavation.[73]

Tunnel boring had resumed on December 22, 2015.[74][75] The tunnel boring was halted 23 days later on January 14, 2016, after a 30-foot-wide (9.1 m) sinkhole developed on the ground in front of the machine, causing Governor Jay Inslee to halt drilling until the contractors can perform a root cause analysis to show that the machine can be run safely.[76] Even though contractors filled the hole with 250 cubic yards (190 m3) of material, the ground above the tunnel-boring machine continued to sink, according to the Washington State Department of Transportation. The tunneling restriction was lifted on February 23, 2016, and tunneling resumed that day.[77] Bertha passed under the Alaskan Way Viaduct in early May, closing the roadway for 11 days as the machine had 15 feet (4.6 m) of vertical clearance under the structure’s pilings.[78] On April 4, 2017, the tunnel boring machine broke through to the recovery pit on the north end of the tunnel, completing the excavation process.[79] The boring machine was dismantled and removed from the site over the next four months.[80]
Back of tunnel boring machine and partially completed tunnel with concrete walls in place in 2017

Dirt produced by tunnel construction was sent to fill a CalPortland quarry in nearby Port Ludlow.[81]

[moehoward]

” The viaduct was 8-lanes.”

It also had off ramps so you could get into downtown. I don’t believe there are any in the tunnel. They just route all the traffic along the water front or 1st ave. It’s a major pooch screw every morning requiring cops to keep intersections clear and traffic moving.

[rockrr]

“Two steps forward and nineteen steps back. It’s the Seattle way!”

[rlmorel]

The cost of the Big Dig in Boston was no doubt greatly inflated by graft and corruption. But there are three major things that drove up the cost of the Big Dig massively that people outside the area rarely if ever hear about.

Disclaimer: While I like what the Big Dig did for Boston, as a conservative, I would never approve of the way it was funded. Never. I don't believe in having money taken from people in Montana to pay for highway projects in Boston. But that is the way, with all the political philandering and corruption was and still is done.

First, Boston had a history that bore heavily on the costs as it went along. In the 1950's when the Central Artery was built through the heart of Boston, thousands of people (I think 12,000) and hundreds of buildings were taken against the will of the residents in the North End (Boston's Little Italy). When the big dig was in the design stage, the state vowed (with a codicil in the written process) that nobody who wanted to stay would be forced to leave. So, they didn't use eminent domain, and paid some seriously big bucks to purchase property. One kind of humorous one (for me, at least) is a skinny, four story old tenement right next to The Boston Garden, surrounded by parking lots and ramps on and off the new roads. It looks so bizarrely out of place, but apparently the owner refused to sell regardless of price.

Every time I see that building I think of the movie "Up"!

Second, there were changes in environmental constraints that were not well understood, and at the time the big dig was taking place, they were coming out of the woodwork. The Howard Zakim Bridge spanning the Charles River, and the widest bridge of its kind built to date at a cost of between $100-150 million dollars, had to be redesigned. Why? Apparently the shadow of the bridge on the water was thought to prevent small sardine-like fish called "Alwifes" from migrating up or down the river. They had to do extensive redesign with special slats to allow light to reach the water below. Who knows what other bizarre environmental issues they had to deal with.

Third, huge areas of Boston were built on landfill, soil that had been moved from one area to another. This is one of the reasons they used a "dig and cover" technique as opposed to a tunneling technique. AND, they did this in one area where they actually had to build a large refrigeration unit that froze a huge section of ground in a key area so they wouldn't have to re-route a key commuter rail system and the main Amtrak system. The soil in that area was completely unstable. Crazy, but you can imagine it.

[NYAmerican]

Is it safe to assume this project was executed using solely “Green” energy? That the tunnel will be utilized by only clean energy Mass Transit vehicles?

[rlmorel]

As I said in my prior post...I love what the Big Dig did for Boston even if I don’t agree with the way it was funded and executed.

Right in the middle of the Big Dig project, our family was visited by an old friend who lived in California. He was involved in large construction projects, not like the big dig, but larger than individual large office buildings.

When he got off the plane in Boston, he was astonished looking at the city. Apparently there are special cranes that you only see at very large projects, and most of the time you only see one or two (according to him). He knew of what he spoke, and he said the most of those kinds of cranes he had ever seen in one spot at one time was four.

At that time, I recall he said he counted twelve of them!

I don’t know what they used them for, but I do know that huge earthmoving machines were routinely lowered through vertical tunnels hundreds of feet down, often with inches to spare around the device as it was lowered.

Pretty impressive stuff.

One of the last things to be done after the tunnels were completed was to actually remove the elevated roadway, a rusty green eyesore that cut the city in half. They apparently accomplished that in a comparatively short time frame.

My wife and I had not gone into Boston for months, and we took the train in...when we got off and walked around the corner near what is called “City Hall Plaza ( a real eyesore of a building in and of itself) we had our breath taken away.

The Expressway was gone. Just gone. You only saw blue sky, where there had formerly been that crappy POS highway that caused so much irritation and traffic misery for decades.

That was pretty cool.

[SkyDancer]

And they closed the Viaduct three weeks before the partial opening of the tunnel.

[SkyDancer]

Because trains don’t go where people want them to go.

[outofsalt]

from wiki
“As of 2019, litigation is ongoing over which parties are responsible for the $642 million repair to the tunnel boring machine.[83][84] Fragments of the steel well casing struck in December 2013 and cited as a possible cause of Bertha’s breakdown were stored as evidence at the construction site and subsequently went missing in 2014.[83][85] Detailed journal entries kept by the tunnel contractor’s deputy project manager between December 2013 and February 2014 also went missing”

[IndispensableDestiny]

Third, huge areas of Boston were built on landfill, soil that had been moved from one area to another.

The hills in and around Boston were pulled down to create the fill. Tough work in the 19th century.

The growth of Boston:

[SuperLuminal]

Speaking of Boston's "cut and cover" disaster: I remember the Boston area when it was "duck and cover"... In elementary school we spent lots of time sitting on cardboard under desks and in hallways..

Had an 80-year-old teacher who would tell us that the "thunderstorms" would be over soon... Like us 8 & 9-year-olds were really stupid...