Offshoot of the Hampton Roads thread: how many tunnel projects have had capacity added after the fact? Here are a few:
* Lincoln Tunnel - opened with 2, expanded to 3, briefly considered 4
* WV and PA Turnpikes (several)
* I-90, Seattle's Mercer Island
* Big Dig - original tunnel dualized and incorporated into final product
* Alaskan Way - existing tunnel to be bypassed by a wider one
Alaskan Way is the only one I can think of in the USA that replaced an existing tunnel with a wider one. The others just added parallel tubes. In some cases, they were designed for such.
The next major tunnel twinning I can foresee is Chesapeake Bay Bridge-Tunnel. Any others on the horizon?
Caidecott Tunnels (CA 24) expanded from three bores to four.
Sumner had Callahan added as essentially a twin tube to form an inbound/outbound pair, though portals are not immediately adjacent.
178th-179th through Manhattan were replaced by I-95.
A railroad tunnel (Winston) in NW Illinois was modified repeatedly over it's useful life. Crews lowered the the floor to allow taller trains, and IIRC the sides were strenghened or rebuilt.
I realize it's not a hiway tunnel, but it's very interesting as a primer on what can be done with an existing tunnel to improve it if there is enough money. Sadly, Winston Tunnel is now abandoned and pretty much destroyed from water ingress and lack of maintenance.
Alaskan Way isn't replacing the existing tunnel with a wider one. The existing tunnel is two lanes (each direction), and I'm 95% sure the new one will be as well. In fact, what they're doing is replacing the 2x3-lane viaduct with a narrower roadway. The existing tunnel is being closed because while it's not as unsound as the viaduct, it is old and deficient, but moreso, it would be too hard to tie it in with the new roadway.
Twin Tunnels just east of Idaho Springs, CO on I-70 -- expansion from 2 to 3 lanes each. Westbound tunnel was finished last year; eastbound tunnel is currently under construction.
Does the Yerba Buena Tunnel count? Opened with 3 lanes of auto traffic in each direction on the upper deck and 3 lanes of truck traffic (1 reversible) plus 2 rail lines on the lower deck before being converted to 5 lanes on each deck.
Quote from: oscar on November 13, 2014, 11:47:43 PM
Caidecott Tunnels (CA 24) expanded from three bores to four.
And it had previously expanded from 2 to 3.
Not a road tunnel, but the Virginia Ave rail tunnel in DC (under Virginia Ave SE and the SE Freeway) is about to be expanded.
Quote from: Alps on November 13, 2014, 11:36:12 PM
Offshoot of the Hampton Roads thread: how many tunnel projects have had capacity added after the fact? Here are a few:
* Lincoln Tunnel - opened with 2, expanded to 3, briefly considered 4
* WV and PA Turnpikes (several)
* I-90, Seattle's Mercer Island
* Big Dig - original tunnel dualized and incorporated into final product
* Alaskan Way - existing tunnel to be bypassed by a wider one
Alaskan Way is the only one I can think of in the USA that replaced an existing tunnel with a wider one. The others just added parallel tubes. In some cases, they were designed for such.
The next major tunnel twinning I can foresee is Chesapeake Bay Bridge-Tunnel. Any others on the horizon?
WV Turnpike didn't get a tunnel expansion...they totally bypassed it like the Laurel Hill tunnel.
Actually the Lincoln Tunnel was opened with one tube. It expanded to two before the last tube opened in 1957.
Quote from: Jardine on November 14, 2014, 01:28:28 AM
A railroad tunnel (Winston) in NW Illinois was modified repeatedly over it's useful life. Crews lowered the the floor to allow taller trains, and IIRC the sides were strenghened or rebuilt.
I realize it's not a hiway tunnel, but it's very interesting as a primer on what can be done with an existing tunnel to improve it if there is enough money. Sadly, Winston Tunnel is now abandoned and pretty much destroyed from water ingress and lack of maintenance.
BNSF (or predecessor BN) cut notches into the upper corners of their Cascade Tunnel in Washington to allow trains with double-stacked containers to clear it and use that route. This has also been done in many other tunnels (ie, CP's ex MILW tunnel near Tunnel City/Tomah, WI) for the same reason.
Mike
In the 1960s, the PA Turnpike doubled the 4 mainline tunnels that are still in use today. The other 3 were bypassed. It wasn't until the '90s that the lone tunnel on the NE Extension (I-476) was doubled as well. Significantly, the second bore was done using NATM (New Austrian Tunneling Method).
There has been talk of improving the Allegheny Mountain tunnel to 3 bores, or just bypassing it.
Quote from: Alps on November 13, 2014, 11:36:12 PM
The next major tunnel twinning I can foresee is Chesapeake Bay Bridge-Tunnel. Any others on the horizon?
I recall reading someplace that there was some consideration given to replacing the current (2 lane) CBBT tunnels with new four lane tubes and then abandoning-in-place the old ones.
Quote from: cpzilliacus on November 14, 2014, 02:04:47 PM
Quote from: Alps on November 13, 2014, 11:36:12 PM
The next major tunnel twinning I can foresee is Chesapeake Bay Bridge-Tunnel. Any others on the horizon?
I recall reading someplace that there was some consideration given to replacing the current (2 lane) CBBT tunnels with new four lane tubes and then abandoning-in-place the old ones.
Well, partially abandoning in place and partially ripping out. The impetus for full replacement instead of twinning would be so the new tunnels could be further down as well as wider, allowing the channels above them to be dredged deeper.
Quote from: Alps on November 13, 2014, 11:36:12 PM
* I-90, Seattle's Mercer Island
A bit late to the topic, but could someone please expand on this one? I thought I-90 across Mercer Island was above ground entirely until the early 90s when the new bridges were built, and the new carriageways were sunk below the lids. I'm about 90% sure that there hasn't been any tunnel widening since they (the lids) were built.
Or is the purpose of the topic to discuss tunnels that were built wider than what they replaced, regardless of whether or not there was a tunnel before? If that's the case, WA 520 was widened and several new tunnels were constructed near the junctions with Yarrow Point and Hunts Point, and another tunnel was built near Evergreen Point, though no junction exists for this peninsula.
The Idaho Springs tunnels west of Denver on I-70 were just recently expanded from 2 lanes to 3 lanes in each direction.
Quote from: ski-man on December 22, 2014, 10:23:46 PM
The Idaho Springs tunnels west of Denver on I-70 were just recently expanded from 2 lanes to 3 lanes in each direction.
Is the eastbound tunnel done now? I drove past there in September (2014) and it looked like they had a fair amount of work left to do.
Quote from: Kacie Jane on November 14, 2014, 01:45:06 AM
Alaskan Way isn't replacing the existing tunnel with a wider one. The existing tunnel is two lanes (each direction), and I'm 95% sure the new one will be as well. In fact, what they're doing is replacing the 2x3-lane viaduct with a narrower roadway. The existing tunnel is being closed because while it's not as unsound as the viaduct, it is old and deficient, but moreso, it would be too hard to tie it in with the new roadway.
Actually, they are replacing a largely 3x3 viaduct with a
3x3 2x2 stacked tunnel, likely because they aren't planning on any entrances or exits along with route, which is poor planning in my opinion. Why in the hell it is stacked it anyones guess. The Battery Street tunnel is being replaced, which I think is what is being referenced. Although, I don't consider Cut and cover to be real tunnels, just capped roadways. It would have likely been cheaper and easer to have two parallel tunnels.
Also, there are no true tunnels on Mercer Island, just cut and cover tunnels, which were added as part of the conversion of US 10 to I-90. The Mt. Baker tunnel, on the mainland was paralleled, not widened.
From the Northeast group:
Pa. Turnpike considers plans to replace Allegheny Tunnels in Somerset County (http://www.post-gazette.com/news/transportation/2014/12/24/Pennsylvania-Turnpike-considers-plans-to-replace-tunnels-in-Somerset-County/stories/201412230034)
The article does explicitly say that expanding the tunnels is not an option, only because it would be hard to safely maintain traffic and would take too long. Either additional bores or a bypass cut through the mountain is discussed.
Also in Pennsylvania, at least two rail tunnels in Pittsburgh were expanded or otherwise modified. Both go through Mt. Washington, same as the Ft. Pitt and Liberty tubes.
One is the Panhandle tunnel, which was modified so both buses and trolleys could use it. The trolley system has since "graduated" to light-rail, possibly bringing more improvements to the tunnel. (This is not to be confused with the new NATM bored tunnel in the Mt. Lebanon area, or the cut-and-cover tunnels downtown, both of which are rails-only.) The other is the Wabash tunnel, which was converted to highway HOV lanes, though I understand the HOV requirement has since been lifted at least for now.
Quote from: TEG24601 on December 26, 2014, 11:45:22 AM
Quote from: Kacie Jane on November 14, 2014, 01:45:06 AM
Alaskan Way isn't replacing the existing tunnel with a wider one. The existing tunnel is two lanes (each direction), and I'm 95% sure the new one will be as well. In fact, what they're doing is replacing the 2x3-lane viaduct with a narrower roadway. The existing tunnel is being closed because while it's not as unsound as the viaduct, it is old and deficient, but moreso, it would be too hard to tie it in with the new roadway.
Actually, they are replacing a largely 3x3 viaduct with a 3x3 2x2 stacked tunnel...
Our notation is different, but that is in fact what I said, so the "Actually..." was unnecessary. The existing viaduct is mostly 3 lanes in each direction (though a significant portion of the southbound roadway was restriped to only two lanes for safer merging), and it's being replaced with a narrower tunnel of only two lanes in each direction.
(I was assuming the proper notation would be
2 carriageways x
3 lanes each, since 2 x 3 = 6 lanes total. Otherwise wouldn't it be 3+3 instead?)
Quote from: cpzilliacus on December 26, 2014, 10:40:53 AM
Quote from: ski-man on December 22, 2014, 10:23:46 PM
The Idaho Springs tunnels west of Denver on I-70 were just recently expanded from 2 lanes to 3 lanes in each direction.
Is the eastbound tunnel done now? I drove past there in September (2014) and it looked like they had a fair amount of work left to do.
Both tunnels are complete, but westbound is still only 2 lanes because the approaches need to be widened to 3 lanes.
Quote from: TEG24601 on December 26, 2014, 11:45:22 AM
Also, there are no true tunnels on Mercer Island, just cut and cover tunnels, which were added as part of the conversion of US 10 to I-90.
I get your point, but I would still count the lids as tunnels. The basic definition of a tunnel is an "artificial underground passage". Given the fact that the freeways pass under the ground, it would seem then that they are indeed tunnels. Sure, compared to something like the Eisenhower Tunnels, lids go under land that was not always there. But the fact remains that they now
do go under land, which would then make them a tunnel.
Quote from: jakeroot on December 27, 2014, 03:49:32 PM
But the fact remains that they now do go under land, which would then make them a tunnel.
Agreed. What about tunnels that go under bodies of water?
QuoteWhat about tunnels that go under bodies of water?
OP mentioned one in the NYC area. Have the Holland and Queens-Midtown Tunnels always been two tubes?
In Norfolk, both the HRBT and Downtown Tunnel were initially single-tube, later dualized. And the Midtown Tunnel is currently being dualized, as those who were at the Hampton Roads meet this past spring saw.
The New Orleans area brings an interesting case: the Belle Chase Tunnel, which was a dualization of a drawbridge across the Intracoastal Waterway....SB LA 23 traffic uses the tunnel, while NB LA 23 traffic uses the drawbridge.
Quote from: froggie on December 29, 2014, 08:58:30 AM
QuoteWhat about tunnels that go under bodies of water?
OP mentioned one in the NYC area. Have the Holland and Queens-Midtown Tunnels always been two tubes?
Yes. One of the proposals for Holland used one large tube, but the one chosen had a tube for each direction since opening.