"This tunnel will be a bargain" -- Big Dig Bashin'

BostonUrbEx

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$54M Big Dig light fix called ‘permanent solution’
By Matt Stout
Thursday, April 5, 2012

A $54 million proposal to replace the more than 25,000 fixtures in the Big Dig tunnels is being touted by MassDOT officials as a “permanent solution” to fix the corroded lights inside the problem-plagued underground highway and ramp system.

The project, slated to begin this time next year pending the MassDOT board’s approval of a bid, would replace the corroding fluorescent fixtures that crashed into the spotlight in February 2011 after a 110-pound fixture fell in the Thomas P. O’Neill Jr. Tunnel, said state Highway Administrator Frank DePaola.

“The lights are safe,” DePaola said. “But if we don’t do something, this will be a continuing maintenance issue we have to deal with, which means road closures. ... This will be the biggest lighting project we’ve done in many years.”

Engineers have fortified all lights in the 7.5-mile system with plastic ties, but MassDOT officials hired an engineering firm last year to examine possible long-term solutions, which included lower-cost options such as replacing all lights with new fluorescent ones or subbing out the fixtures’ fastening system.

Officials instead opted for a complete overhaul to energy-saving LED lights, which last 12 to 15 years — compared to two for fluorescent — and should save $2.5 million a year on the tunnels’ electrical bill, DePaola said.

They also feature plastic fixtures, which should help eliminate concerns of corrosion that DePaola admitted is happening “faster than we would have liked.”

Slated to last two years, work would largely be done overnight from 11 p.m. to 5 a.m., likely starting first with the tunnels before moving to the system’s main arteries, DePaola said. The project needs the board’s approval, but DePaola was confident he’d get the green light.

“There was a lot of things they didn’t like at the board meeting, and this they did,” MassDOT spokeswoman Sara Lavoie said, referencing the heated discussion board members heard yesterday before voting to enact steeper T fares. “They liked the energy savings.

“We needed a permanent solution,” she added, “and we think this $54 million proposal is the solution.”

Money for the project would come from a maintenance fund, established four years ago, Lavoie said.

DePaola said the highway administration’s legal department is still trying to determine who’s to blame for the corrosion of the fixtures, adding the manufacturer, NuArt, was bought out and is no longer in business, compromising chances of recouping any of the costs.

“I don’t know how that’s going to come out,” he said.



Highway boss: Big Dig ‘sinkhole’ a pool of mud
By Richard Weir
Thursday, April 5, 2012

The so-called sinkhole that officials feared had emerged underneath Interstate 90 connector tunnels is instead a “pool of mud” that will need to be filled with pressurized cement to prop up the roadway’s infrastructure, said a state transportation official.

“We have a zone of loose soil that is not providing subgrade support. The tunnel is like suspended through a pool of mud,” said state Highway Administrator Frank DePaola. “It’s like a mud puddle. You step in a mud puddle, it’s not going to hold you up.”

Transportation officials last summer announced a void likely had formed under the tunnels where large patches of earth were chemically frozen to allow train service into South Station during Big Dig construction.


News of what DePaola then referred to as a “sinkhole” prompted U.S. Rep. Stephen Lynch to call for a federal probe into the tunnels’ safety and for the state to hire a private contractor, GZA GeoEnvironmental of Norwood, to conduct boring samples. DePaola provided the firm’s test results and recommended the remedy to the MassDOT board yesterday.

“As we’ve said before, we’ve concluded that the tunnel can bridge across this loose zone,” he said. “We don’t have any immediate concerns about the structural stability but I realize it’s unsettling for people. ... The tunnel is safe, but I want the tunnel to be there for 100 years and for people to stop worrying about it.”

To that end, he said, the state next year will hire a contractor to dig a 90-foot shaft below the concrete box tunnels to pump in 100 tons of cement grout to “firm up” the marine clay that turned to a muddy mix after it thawed.
 
2 years to replace the lights seems like a very long time.

Then again the Park Street elevator is going on 2 years now, so nothing surprises me.
 
This will be expensive. They'll probably have to limit the times the tunnel is open, raise tolls, and maybe even close some of the connector ramps. Oh wait, this is for cars and not the T? Oh, then I guess not.
 
Looks like the payback on the lights will be faster than a chevy volt's payback.
 
Until the plastic used is found to degrade from the engine exhaust from someone failing to select vapor tight and resistant fixtures.
 
2 years to replace the lights seems like a very long time.

Then again the Park Street elevator is going on 2 years now, so nothing surprises me.

Mass -- They should bite the bullet and install LEDs -- capital costs might be higher -- but down the road the electricity costs will be less than 1/2, and the routine maintenance involved in replacing of bulbs can be completely zeroed out for at least 10 years.
 
They are doing exactly that, from what I've read (maybe in the Globe?)
 
Mass -- They should bite the bullet and install LEDs -- capital costs might be higher -- but down the road the electricity costs will be less than 1/2, and the routine maintenance involved in replacing of bulbs can be completely zeroed out for at least 10 years.

It's all the labor costs. Highway installs may be different, but most municipal street lighting is charged by NStar at a per-fixture rate...not metered by usage. So all these towns that are now installing them (just started sprouting up all over East Watertown last week!) get no breaks whatsoever on electricity bills until they can renegotiate lower per-fixture rates with NStar. NStar, in the meantime, now gets to make the same money for half the juice. But it's such an overpowering slam-dunk on maintenance and labor savings that local municipalities are springing for it anyway. Boston's now moving forward with replacing post-top lighting in parks with LED's, so the Common and Public Gardens are probably going to have those retrofits by end of spring.



LED's ain't as likely to kill you falling like bricks from a ceiling, either. I never understood why those Big Dig fluorescents were so goddamn bulky when the newest-gen electronic ballast tube fixtures in every house, store, office, etc. are half the weight of the old-style magnetic ballast ones from 20 years ago. Who decides to use tube fixtures heavy enough to crush a compact car?
 
LED's ain't as likely to kill you falling like bricks from a ceiling, either. I never understood why those Big Dig fluorescents were so goddamn bulky when the newest-gen electronic ballast tube fixtures in every house, store, office, etc. are half the weight of the old-style magnetic ballast ones from 20 years ago. Who decides to use tube fixtures heavy enough to crush a compact car?

People smart enough to figure that if they sell dated technology to the project, then sign a contract to provide replacements they get to supply new fixtures in a few years?
 
Is the BIG DIG Tunnel SAFE?

If the lights are corroded wouldn't that mean there is a bigger problem like water underneath the lights causing corrosion?
 
Is the BIG DIG Tunnel SAFE?

If the lights are corroded wouldn't that mean there is a bigger problem like water underneath the lights causing corrosion?

Riff -- that one is on target -- BullsEye!

The O'Neil Tunnel interior where the lights are corroding away -- is sort-of-connected to the Atlantic Ocean

To save money -- they didn't do the standard "tunnel-within-a-tunnel" -- they just did a single-wall tunnel, and so the water will always be there finding its way in

And -- since the water is salty -- its really good at corroding things made of metal - particularly steel and aluminum
 
Riff -- that one is on target -- BullsEye!

The O'Neil Tunnel interior where the lights are corroding away -- is sort-of-connected to the Atlantic Ocean

To save money -- they didn't do the standard "tunnel-within-a-tunnel" -- they just did a single-wall tunnel, and so the water will always be there finding its way in

And -- since the water is salty -- its really good at corroding things made of metal - particularly steel and aluminum

I'm no engineer but at this point......Then the O'Neil Tunnel will collaspe over time if your statement is true Whigh?
 
On LED's: the Globe article cited a $54M construction cost and $2.5M in annual electricity savings. That's a 5% return before even considering the savings in maintenance/replacement (since LED last considerably longer).
Seems like this was a no brainer even if there weren't corrosion problems.
 
On LED's: the Globe article cited a $54M construction cost and $2.5M in annual electricity savings. That's a 5% return before even considering the savings in maintenance/replacement (since LED last considerably longer).
Seems like this was a no brainer even if there weren't corrosion problems.

That depends on whether they're metered fixtures. Every municipality that installs these trumps up the energy savings argument, but like I said when NStar's got 'em on a per-fixture rate they pay the same either way. So it depends on how MassHighway is rated by the utilities for its fixtures.

It's still silly no-brainer for reliability, maintenance, and safety. Especially in a tunnel where sideways light is a visibility non-factor. It'll be a much nicer drive with the purely unidirectional light reducing glare when you go in and out of the tunnel and have to adjust your eyes. LED's work even better when it's in a linear strip configuration like tunnel lighting vs. pole mount where you have to be precise about the fixture spacing to avoid having dark spots between fixtures.
 
I'm no engineer but at this point......Then the O'Neil Tunnel will collaspe over time if your statement is true Whigh?

Not if they keep up with maintenance and mitigate at the source. The tunnels that are having the engineering (as opposed to contractor corruption) problems are the Pike tunnel and single-layered slurry wall main tunnel where the construction methods were never before used on any major civil engineering project. They did unlayered slurry walls because it was the only way to cram an extra lane of traffic and turnouts on the same footprint as the old Artery, and they had to do the ground freeze to jack the surface while navigating around such a complicated maze of tunnels. They knew they were going to have groundwater seepage and thawing issues from Day 1. Where it's gone awry is that the contractors were lackadaisical while they had the ground torn open about documenting subsurface conditions, and of course when they were doing finishing work on the backside of the project they were cutting corners left and right oversight-free. So the scope of the problem became a big fucking surprise.

The Pike tunnel's "mud cavity" is the scariest one in concept, but the concrete pumping is a permanent fix. So long as they do an accurate determination of how much ground thaw is left to go (and it can't be much a decade later) and don't completely miss another gigantic reservoir of liquified goo in an empty cavity, the ground will be stronger than ever after they pump in the filler. It's just a too-likely assumption that they're going to miss something and have to go back and do it again and again when they find another cavity.

The leakage in the main tunnel is more vexing because 1) they're still in repressing info mode and continually underquote to the public exactly how many gallons are spilling from how many places; 2) this whole things crashing from the ceiling and KILLING PEOPLE risk that we likewise aren't getting straight answers on, and 3) can anyone say with confidence that the contractor corruption with the ceiling plate epoxy glue was only limited to the Pike tunnel? And in each case you can clearly see that it's the public trust issues that are most problematic. Tunnels through the water table leak. And will leak unevenly. The engineering task is to mitigate it to a controlled minimum and not get nasty surprises where gushers open up where there were none before. And do it before it hits deferred maintenance territory like the Red Line Alewife extension where they just let it leak like a sieve for 25 years before doing anything. These are patchable leaks. If they do due diligence on the discovery phase, stay on top of the patches, and even it out to a trickle instead of widespread gushers like this scary situation...then the tunnel is so extremely overbuilt and designed to handle a reasonable leak load that it'll last a hundred years under persistent (but manageable) seepage. As for the ceiling, that's the lowest leak risk, but it obviously ain't helped by the influx of salt from the gushers on the side walls. Fix the side walls and be GODDAMN SURE that epoxy is safe and ceiling mounts like the lights are safe and that problem drops below any sort of trace-effect threshold.

General competence can manage that. We haven't had general competence managing this project, and there's little confidence that's going to start anytime soon.


But at least it's only those two tunnels. The Ted is holding up very well now 17 years after opening. The remade Dewey Sq. tunnel (obviously not new structural construction) is doing well. And all surface structures are holding up nicely...that annoying grooved pavement even keeping nice and intact without the embarrassing premature decay of the main tunnel or the Transitway. So it's not like the whole thing is a house of cards. It's two tunnels built on elevated engineering risk, mismanaged to hell, with vexing fixes the public has zero confidence the personnel are up to because they can't even stop habitually misleading people on the PR end.
 
But at least it's only those two tunnels.

???

If ANY tunnel in Boston were to collapse... any at all... then essentially every major piece of transportation infrastructure is immediately fucked. If the central artery goes, immediately scratch off the Ted and the Sumner/Callahan. I'm not positive, but I suspect the Summer St concourse is tied in to emergency egresses for the central artery, meaning that the Red Line and Silver Line are toast, if not but some other means, such as the weight collapsing the floor into the Red Line or penetrating in some other way. The Pike ramps at 93 are below sea level and by the time they're at grade with the Pike, the Pike is at sea level, so essentially that's flooded out to the Pru and the Orange Line takes it in the ass come high tide.

The best I can tell, due to elevations, the Green Line and Blue Line are the only things spared. And that's assuming that any utilities or emergency egresses at Aquarium, if there are any, aren't connected to the Central Artery.



Don't mind me, just love a good disaster scenario.
 
???

If ANY tunnel in Boston were to collapse... any at all... then essentially every major piece of transportation infrastructure is immediately fucked. If the central artery goes, immediately scratch off the Ted and the Sumner/Callahan. I'm not positive, but I suspect the Summer St concourse is tied in to emergency egresses for the central artery, meaning that the Red Line and Silver Line are toast, if not but some other means, such as the weight collapsing the floor into the Red Line or penetrating in some other way. The Pike ramps at 93 are below sea level and by the time they're at grade with the Pike, the Pike is at sea level, so essentially that's flooded out to the Pru and the Orange Line takes it in the ass come high tide.

The best I can tell, due to elevations, the Green Line and Blue Line are the only things spared. And that's assuming that any utilities or emergency egresses at Aquarium, if there are any, aren't connected to the Central Artery.



Don't mind me, just love a good disaster scenario.


Urb -- people always wonder why you come out into the sunshine when you enter the I-90 tunnel from the Pike enroute to Logan -- real basic hydraulics

If one of the tunnels floods -- the open hole keeps syphoning from carrying water up over the top and then down again to flood everything. That's also why the Red Line had some gates put in to isolate the section passing through the Fort Point Chanel and under the immersed tube tunnels for I-90 that were then towed into place and sunk onto the 100+ support piers. if the I-90 tunnel had missed and broken the Red Line the flooding would have been confined.

I think the most servious threat to the T system would be a breach of the Blue Line trans-harbor Tunnel. That breach would flood Aquarium, State, Government Center Blue Line platforms and I suspect that State would couple the flood into the Orange Line. If that part of the scenario is valid then you'd lose Haymarket, DTX and Chinatown on the Orange. The big question is what happens to the Red Line at DTX -- over flow (not syphoning as everything is open to the air) could then flood South Station, the Silver Line Tunnel to Courthouse and possibly Park Street. A lot of buildings are connected to the T through entrances or just emergency passages -- it would be an interesting project for some student interested in infrastructure and modeling -- probably get a grant from DHS
 
Blue's been dry as a bone under the Harbor for a century. That one is your shining example of untested civil engineering in this city done right. Nobody knew what to expect in 1900 when they dug that one.

The only thing that's a serious threat to the tunnels is a major earthquake. But the silt they're laid through has more flex than solid rock so even that shouldn't be a problem. The Ted is sunken steel cassions, which is pretty tried-and-true everywhere around the world.

Really, the Pike tunnel is the most untested construction method of the whole project with the cryogenic-freeze ground jacking. Even moreso than the unlined slurry walls, which has well-known properties with the only unknowns being scale of the project. It was predictable they were going to have problems with the Pike tunnel, and predictable that they were going to need a fix (the soil, not the criminal negligence with things falling from the ceiling). But they better fucking know 100% of what's settled underneath and leave no stone unturned finding out end-to-end, and everywhere else in the ground thaw zone. The fix isn't a problem...once the concrete's poured into the cavity it's solid for life. It's the cavities they don't know about, haven't looked hard enough to find, or haven't told the public about that are scary, scary shit.
 

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