Alaskan Way Viaduct Replacement Tunnel

[Bickendan]

That, to me, is the tunnel's biggest flaw: Lack of downtown access. Reconfiguring I-5 would have been a better use of the tunnel's money, but at this point, it'd be foolish not to complete the tunnel. If there were a way to include downtown exits to the tunnel while minimally impacting the buildings or streets, it should be designed and built down the line after the initial tunnel opening, though that would be difficult, particularly since the Seneca and Columbia St ramps worked well with the topography. You could possibly have the onramp facing east at Marion and Western, and the offramp coming up from under the old Seneca onramp.

[iBallasticwolf2]

That, to me, is the tunnel's biggest flaw: Lack of downtown access. Reconfiguring I-5 would have been a better use of the tunnel's money, but at this point, it'd be foolish not to complete the tunnel. If there were a way to include downtown exits to the tunnel while minimally impacting the buildings or streets, it should be designed and built down the line after the initial tunnel opening, though that would be difficult, particularly since the Seneca and Columbia St ramps worked well with the topography. You could possibly have the onramp facing east at Marion and Western, and the offramp coming up from under the old Seneca onramp.

I think the point of the tunnel was to bypass downtown because with only 2 lanes in each direction if it had exits to downtown it would get more traffic and be super-congested. It will have an exit to downtown as the Alaskan way surface street however. The tunnel is for thru motorists not wanting to use I-5. It also bypasses I-90 which could be very congested.

[jakeroot]

That, to me, is the tunnel's biggest flaw: Lack of downtown access...If there were a way to include downtown exits to the tunnel while minimally impacting the buildings or streets, it should be designed and built down the line after the initial tunnel opening, though that would be difficult, particularly since the Seneca and Columbia St ramps worked well with the topography. You could possibly have the onramp facing east at Marion and Western, and the offramp coming up from under the old Seneca onramp.

Even if there's a few crazies in the anti-Bertha camp, it still is kind of a huge waste of a project. The tunnel will carry less traffic than the old viaduct because it doesn't have downtown exits, which were heavily used by commuters from West Seattle. There's better ways of spending the money that went into this project (reconfiguring I-5 and all of its left exits and the reversible express lanes, funding the last mile of the SR 520 project in Seattle, etc.) that would've benefitted Seattle and its commuters much more.

You still have to do something about the viaduct, which has to come down (none of the alternatives allowed keeping the viaduct as-is).

That aside, additional lanes do not inherently increase roadway capacity. Additional infrastructure surrounding the tunnel (such as improved surface streets and well-functioning portals that allow easy ingress and egress from downtown) will be the key in keeping the tunnel from suffering from congestion. Not to mention, the tunnel only exists to funnel traffic from north/south of the city to the opposite end. WSDOT is able to only have two through lanes in each direction because downtown traffic will not use the roadway anymore.

The only place where I sense an issue is that the access to/from Elliott will effectively disappear. I sense that the reconstruction of Mercer is meant to rectify this issue, but I'm playing the waiting game to see how that works out.

I think the point of the tunnel was to bypass downtown because with only 2 lanes in each direction if it had exits to downtown it would get more traffic and be super-congested. It will have an exit to downtown as the Alaskan way surface street however. The tunnel is for thru motorists not wanting to use I-5. It also bypasses I-90 which could be very congested.

Bingo.

[kkt]

Reconfiguring I-5 downtown would be nice, but it would cost way, way more than the tunnel.  Even with Bertha's problems.  And I-5 isn't going to fall down in the next earthquake, so it's a less urgent problem.

[Bruce]

Reconfiguring I-5 downtown would be nice, but it would cost way, way more than the tunnel.  Even with Bertha's problems.  And I-5 isn't going to fall down in the next earthquake, so it's a less urgent problem.

It's better to start the discussion now and let the Seattle process play out before I-5 starts to have visible cracks and other age-related problems. I don't think I-5 will be reconstructed until I reach retirement age, but at the very least we can prevent rushed decisions that will come back to bite us in another 50 years (e.g. the 2-lane northbound thru lanes under the Convention Center).

[iBallasticwolf2]

Reconfiguring I-5 downtown would be nice, but it would cost way, way more than the tunnel.  Even with Bertha's problems.  And I-5 isn't going to fall down in the next earthquake, so it's a less urgent problem.

It's better to start the discussion now and let the Seattle process play out before I-5 starts to have visible cracks and other age-related problems. I don't think I-5 will be reconstructed until I reach retirement age, but at the very least we can prevent rushed decisions that will come back to bite us in another 50 years (e.g. the 2-lane northbound thru lanes under the Convention Center).

The fact that there are only 2 through lanes at the convention center is BAD. For a city the size of Seattle it would need to be at LEAST 3 through lanes if not 4. However with the Seattle process and the tunnels it would be a long process to improve I-5.

[Thunderbyrd316]

   I for one am VERY skeptical of claims that the Alaska Way Viaduct was ever in any danger of collapsing in an earthquake. (Just because a freeway is a "double decker" does NOT mean that it will automatically collapse like the Nimitz did in '89. The Nimitz Freeway was in atrocious condition the last time I drove on it in April of 1989, just 6 months before it collapsed. Every section of that roadway was visibly and significantly sagging between each set of supports and I actually commented to my father as we drove along it that "If there is ever an earthquake, this thing is going to fall over."

   I personally believe that the citizens of the Northwest have been duped by the politicians and bureaucrats as they so often are. This whole endeavor was just an excuse to spend wads of tax payer money and eliminate a dated but still functional freeway in favor of a more "politically correct" roadway with lower speed limits, fewer lanes and tolls for those "evil" automobile drivers.

   Consider these facts; Alaska Way Viaduct (as it was before they started messing it up): 6 lanes, 50 m.p.h. speed limit, incredible, tourist worthy views (North Bound) of down town, Olympic Mountains and Puget Sound, historically significant as first truly modern urban freeway in the Northwest, no tolls. New Tunnel: 4 lanes, 40 m.p.h. speed limit, no view of anything, no historic significance, tolls (which will certainly grow just as they have with the Narrows Bridge) that require government tracking of your vehicle and massive expense to the tax payers.   

[iBallasticwolf2]

   I for one am VERY skeptical of claims that the Alaska Way Viaduct was ever in any danger of collapsing in an earthquake. (Just because a freeway is a "double decker" does NOT mean that it will automatically collapse like the Nimitz did in '89. The Nimitz Freeway was in atrocious condition the last time I drove on it in April of 1989, just 6 months before it collapsed. Every section of that roadway was visibly and significantly sagging between each set of supports and I actually commented to my father as we drove along it that "If there is ever an earthquake, this thing is going to fall over."

   I personally believe that the citizens of the Northwest have been duped by the politicians and bureaucrats as they so often are. This whole endeavor was just an excuse to spend wads of tax payer money and eliminate a dated but still functional freeway in favor of a more "politically correct" roadway with lower speed limits, fewer lanes and tolls for those "evil" automobile drivers.

   Consider these facts; Alaska Way Viaduct (as it was before they started messing it up): 6 lanes, 50 m.p.h. speed limit, incredible, tourist worthy views (North Bound) of down town, Olympic Mountains and Puget Sound, historically significant as first truly modern urban freeway in the Northwest, no tolls. New Tunnel: 4 lanes, 40 m.p.h. speed limit, no view of anything, no historic significance, tolls (which will certainly grow just as they have with the Narrows Bridge) that require government tracking of your vehicle and massive expense to the tax payers.   

Well the viaduct was actually causing the waterfront to suffer plus it had no shoulders. Besides the tunnel bypasses downtown so the smaller amount of lanes isn't too bad. Additionally the viaduct was actually dated.

[Bruce]

The fact that there are only 2 through lanes at the convention center is BAD. For a city the size of Seattle it would need to be at LEAST 3 through lanes if not 4. However with the Seattle process and the tunnels it would be a long process to improve I-5.

I would probably steal a lane from the C/D lane and make the reversible express lanes into a two-way HOV 3+ expressway (possibly tolled to pay for all of this). That should help a little bit without a significant amount of construction.

   I personally believe that the citizens of the Northwest have been duped by the politicians and bureaucrats as they so often are. This whole endeavor was just an excuse to spend wads of tax payer money and eliminate a dated but still functional freeway in favor of a more "politically correct" roadway with lower speed limits, fewer lanes and tolls for those "evil" automobile drivers.

   Consider these facts; Alaska Way Viaduct (as it was before they started messing it up): 6 lanes, 50 m.p.h. speed limit, incredible, tourist worthy views (North Bound) of down town, Olympic Mountains and Puget Sound, historically significant as first truly modern urban freeway in the Northwest, no tolls. New Tunnel: 4 lanes, 40 m.p.h. speed limit, no view of anything, no historic significance, tolls (which will certainly grow just as they have with the Narrows Bridge) that require government tracking of your vehicle and massive expense to the tax payers.   

The viaduct is in no way historically significant and preservable. I say that as a roadgeek and an amateur historian. It would be much better to have a nice pedestrian-oriented plaza on the waterfront than to keep and continually rehabilitate the viaduct, which serves as a giant wall between downtown and her waterfront.

The "tourist worthy views" (which you can't stop and appreciate, so what's the point?) are not dissimilar to those found from CenturyLink Field, around King Street Station, and on the Seattle Great Wheel. We have plenty of public viewpoints from the north and south, so it's not worth saving.

The tunnel does have historical significance already, with the entire Bertha debacle now etched into the fabric that is Seattle's transportation woes. It's hard to argue that the viaduct has any more, especially prior to its opening.

[kkt]

   I for one am VERY skeptical of claims that the Alaska Way Viaduct was ever in any danger of collapsing in an earthquake. (Just because a freeway is a "double decker" does NOT mean that it will automatically collapse like the Nimitz did in '89. The Nimitz Freeway was in atrocious condition the last time I drove on it in April of 1989, just 6 months before it collapsed. Every section of that roadway was visibly and significantly sagging between each set of supports and I actually commented to my father as we drove along it that "If there is ever an earthquake, this thing is going to fall over."

WashDOT reports the Viaduct's sinkage rate every six months.  Highlights from March:  two new cracks in columns.  Additional 1/8 to 1/4 inch of settling near Seneca St., in addition to the 1/16 settling as of last October.

http://www.bizjournals.com/seattle/news/2015/04/07/more-cracks-detected-in-alaskan-way-viaduct.html

While WashDOT says it's still safe for everday use, I don't think they're exagerating the need to replace it sooner rather than later.

[Bickendan]

Plus, if memory serves, the viaduct did suffer some damage in the Nisquilly Quake.
While I'll be sad when the Alaskan finally gets torn down, I think it is time.

[jakeroot]

New Tunnel: 4 lanes, 40 m.p.h. speed limit, no view of anything, no historic significance, tolls (which will certainly grow just as they have with the Narrows Bridge) that require government tracking of your vehicle and massive expense to the tax payers.   

Four Lanes: Not as much traffic will be using the tunnel as before, you don't need eight lanes (though it was mostly six lanes anyways).
40 MPH Speed Limit: This has not been decided to my knowledge -- source?
No View: Fair enough. But an opened waterfront without the viaduct will be a thing of beauty in and of itself.
No Historic Significance: Not necessary for a successful highway project???
Tolls and other conspiracy theories: Highway funding has changed drastically in the last 60 years -- the government doesn't just step in every time we need a new freeway

[kkt]

Views for people whose eyes should be on the road is not as important as views for people whose feet are on the ground.

[myosh_tino]

The Nimitz Freeway was in atrocious condition the last time I drove on it in April of 1989, just 6 months before it collapsed. Every section of that roadway was visibly and significantly sagging between each set of supports

I don't ever recall seeing portions of the Cypress Structure sagging between support columns granted it's been 25+ years since any of us drove that portion of I-880.

What do remember about the collapse was the fact that, the upper deck collapsed onto the lower deck but, for the most part, the lower deck did not collapse to the ground.  I also remember that studies into the collapse focused on the design of the support columns between the upper and lower decks of the freeway.  I made this drawing for a different thread on these forums...



You'll notice the tapered nature of the support column (wide at the top, narrow at the bottom).  The Loma Prieta Earthquake shook the freeway horizontally causing the columns to shear at the bottom which caused them the splay outward...



While it may be entirely possible there was some sagging of the upper deck, I am still of the belief that the the lateral movement during the quake coupled with what I would call a design flaw in the support columns is what caused the collapse.  I don't think the Cypress Structure was in "atrocious" condition.  Just my two cents.

[kkt]

Reconfiguring I-5 downtown would be nice, but it would cost way, way more than the tunnel.  Even with Bertha's problems.  And I-5 isn't going to fall down in the next earthquake, so it's a less urgent problem.

It's better to start the discussion now and let the Seattle process play out before I-5 starts to have visible cracks and other age-related problems. I don't think I-5 will be reconstructed until I reach retirement age, but at the very least we can prevent rushed decisions that will come back to bite us in another 50 years (e.g. the 2-lane northbound thru lanes under the Convention Center).

The fact that there are only 2 through lanes at the convention center is BAD. For a city the size of Seattle it would need to be at LEAST 3 through lanes if not 4. However with the Seattle process and the tunnels it would be a long process to improve I-5.

The 2-lane stretch is less than ideal, but the backups are usually worse between WA 520 and Mercer St. in my experience.  The Convention Center segment would be very expensive to fix -- expensive real estate and difficult construction on both sides.  The Mercer Weave has a better chance of getting fixed in my lifetime.  The land around it is merely expensive, instead of hideously expensive.

[Bruce]

Ah, the Mercer weave. It seems as if it was originally built as a stopgap between the completion of SR 520 and the proposed construction of the Bay Freeway on Mercer Street (which was cancelled in 1972). Ideally, we'd demolish the SR 520 interchange and reconfigure it to have right-side ramps, but that would be costly and disruptive to the drivers using it.

[jakeroot]

Ah, the Mercer weave. It seems as if it was originally built as a stopgap between the completion of SR 520 and the proposed construction of the Bay Freeway on Mercer Street (which was cancelled in 1972). Ideally, we'd demolish the SR 520 interchange and reconfigure it to have right-side ramps, but that would be costly and disruptive to the drivers using it.

That would help SB I-5 drivers, but those going from Mercer to 520 East still need to merge over 4 lanes since the merge is also on the left. That would also need reconstructing. I believe this is called the 520 Shuffle.

[The Ghostbuster]

Has there been any updates on when/if construction on the tunnel will resume?

[Henry]

As soon as Bertha is fixed, then construction shall continue.

[jakeroot]

Has there been any updates on when/if construction on the tunnel will resume?

The tunnel boring is certainly not proceeding ATM due to Bertha (and as Henry said, once she's fixed, the tunneling will resume), but the construction involving everything else (north and south portals, the part of the tunnel already dug) is still proceeding.

[707]

Suppose once the maintenance is completed, Bertha breaks down yet again? Is there any possibility of the tunnel being outright cancelled along its full length and being replaced by a surface boulevard partway?

[jakeroot]

Suppose once the maintenance is completed, Bertha breaks down yet again? Is there any possibility of the tunnel being outright cancelled along its full length and being replaced by a surface boulevard partway?

No. That would be way too expensive.

[kkt]

Suppose once the maintenance is completed, Bertha breaks down yet again? Is there any possibility of the tunnel being outright cancelled along its full length and being replaced by a surface boulevard partway?

No. That would be way too expensive.

As opposed to rescuing Bertha again if she breaks down somewhere we can't just dig straight down?  Like under a building?  Could easily have happened...

[Bruce]

Suppose once the maintenance is completed, Bertha breaks down yet again? Is there any possibility of the tunnel being outright cancelled along its full length and being replaced by a surface boulevard partway?

No. That would be way too expensive.

As opposed to rescuing Bertha again if she breaks down somewhere we can't just dig straight down?  Like under a building?  Could easily have happened...

The tunnel route goes right under parts of Pike Place Market, which would make it unreachable.

[intelati49]

Just read through the entire thread... HFS I didn't realize it was that bad. Big Dig 2.0 for sure.