I-35W/I-94 Commons

[Tom H.]

If they can deep bore the 2nd Ave Subway in NYC, I'm pretty sure there's a way to tunnel under Lowry Hill in Mpls.

[seanrichardryan]

Yes, there is a 'way'. The Second Ave subway cost 2,000,000,000 per mile.

[RailBaronYarr]

A better comparison is the deep boring under Seattle, that has historic buildings, pilings for earthquake-resistant towers, and rail tunnels. But again, expensive as hell.

[UptownSport]

Yes, all so very helpful. Below is what you are going to get.

p. 2
https://forum.streets.mn/viewtopic.php?p=15886#p15886

This seems to have disappeared from the http://www.35lake.com/ site ...

This remains as justification for the 35W Lake project;

There are two bridges in the I-35W Transit/Access Project that must be replaced by 2018 under the Chapter 152 legislation. These are the “braid” bridge near 24th Street and the “flyover” bridge that connects northbound I-35W to westbound I-94. Replacement of the braid bridge provides an opportunity through a slight design change to land the bridge on the right side of southbound I-35W rather than the left side, thus accommodating a future continuous managed lane from downtown to the new transit station and beyond. Replacement of the flyover bridge offers an opportunity through a slight design change to ease congestion in the I-94 commons area that results from having a lot of traffic trying to merge in one location.

[mister.shoes]

So I've been thinking about this problem for quite literally months. The idea of a deep bore I94 tunnel is really intriguing, for obvious reasons. While everyone who has posted ideas thus far has great thoughts, I think the key to making a tunnel of this sort work is having the west portal be well north of 394. Trying to get the tunnel above ground quickly enough to connect to the existing 394 ramps is just too difficult. Plus, the existing 394 ramps are sharp and dangerous and too close to the Hennepin/Lyndale triangle, forcing that entire area to be a huge mess. I realize that moving the portal makes connecting 394 to 94 more difficult, but as this is a pie-in-the-sky idea, I've added underground exit/entrance ramps. Why not, right? The tunnel would have to stay deep enough long enough to get under Basset Creek, which shouldn't be too tough if the portal is up by Olson Hwy.

Anyway, I started with RBY's idea for the multi-way boulevard and the roundabouts at the triangle and in front of the Basilica, as well as the land bridge connecting the sculpture garden with Loring Park:

I liked the idea so much that I put together a combination of a couple ideas I had seen: https://mapsengine.google.com/map/edit? ... x2b9LCQA7Q

Here are some highlights/helpful bits:

• 35W and 394 are red. 94 is blue. 394 carpool lanes are orange. Ramps between interstates are purple. Ramps to surface streets match the color of their interstate.
• Surface streets are bright blue. Bike paths are bright green. The Nicollet streetcar is black.
• Reclaimed land used as a park is light green.
• Reclaimed land available for development is brown.
• The land bridge between the parks is dark green.
• On 35W, the downtown exit lanes are in the middle, which allows the HOV lanes to remain intact all the way to DT.
• I kept the 3rd Ave bridge intact and treated it as the tunnel portal. Why tear down a perfectly good unnecessarily embellished bridge? *cough*
• I kept the fancy dancy bicycle bridge that connects Bryant Ave to a new bike trail heading east. Because it's pretty, that's why.
• 16th/15th/Oak Grove/Vineland becomes a pretty important E/W street.
• The peanut-shaped roundabout at Groveland/MWB seems pretty ridiculous, but the angle of intersection for those two streets proved really complicated. I kind of like the idea, though. It's fun.
• On top of the land bridge, I added very narrow one-ways between Hennepin/Dunwoody and Oak Grove/Vineland. The easterly one follows Old Hennepin Ave. The westerly one wouldn't be necessary if Van White had connected to Stadium Parkway. Le sigh.
• Laurel Ave connects west across Lyndale to Aldrich.
• North of 394, Lyndale becomes much more friendly. There are still freeway lanes sandwiched in the middle, but I was able to add bike lanes all the way up to Olson Hwy and connect them to the Cedar Lake trail.
• Both the Basilica and Farmers' Market lose their under-the-freeway parking lots, but it's worth it, IMO.

I toyed with the idea of adding a Hennepin Ave alignment for the SW LRT. I think it would be fun to repurpose a portion of the Lowry Tunnel as a subway stop. The Guthrie's foundation would be a challenge to get around, but from there the line could go NW to the currently planned Van White station and follow that route to The Interchange. Maybe v.2 of this map.

Enough blabbing. The result was this:

Click for the full size version

[bubzki2]

Very nice! Wow, if only. If only.

[talindsay]

Love it. Never going to happen because it would cost billions, but I love it. If I ever become Bill Gates I'll lose the nerdy glasses and then I'll fund this.

[mister.shoes]

Because I can't leave well enough alone...

• Cleaned up the ramps to 94 up by Olson Hwy. No more wacky weave.
• Moved the point where the 94 ramps split from Lyndale so Linden Ave can be reconnected.
• Got rid of the peanut-shaped double roundabout and realigned the MWB where it intersects Groveland and Clifton using two separate small roundabouts. This makes the newly developable land more contiguous and the street alignment more sensible.
• Added a loop ramp from 16th Street/3rd Ave S to WB 94. I had overlooked that movement on my first version. It seems unnecessary, but I didn't want to remove any existing access.

Click for the full size version

[RailBaronYarr]

Very clean images, and I really like the modifications. I also like the idea of extending the tunnel further up, even if it would cost more to do it and add tunneled entrance ramps to/from 394. Would be great to see this done and use redevelopment to help fund it, along with increased property values in existing land from the removal of a loud freeway adjacent to them. The tunnel would be ~1.5 miles, how would this compare to the Alaskan Way tunnel for technical difficulty?

[Wedgeguy]

The one difficulty that I see is the high water table in that area. Not sure what the soil conditions would be in that area. Where bedrock is etc. If they can do the Boston tunnels then this is a possibility. But it will be a piece of work and a few more bucks than normal!

[David Greene]

I toyed with the idea of adding a Hennepin Ave alignment for the SW LRT. I think it would be fun to repurpose a portion of the Lowry Tunnel as a subway stop. The Guthrie's foundation would be a challenge to get around, but from there the line could go NW to the currently planned Van White station and follow that route to The Interchange.

That's a really interesting idea. Totally impractical, I'm sure, but it would maintain Van White, though the loss of Penn would be a blow. It's something I could probably get behind, however.

[RailBaronYarr]

I could also really get behind that. A Hennepin route that passes under the Greenway, mid-cruve westward with a station to meet up vertically with other lines, then uses the Mall to portal just south of the Midtown track alignment and meet up with it before crossing the channel between Isles/Calhoun would be perfect. The Lowry Hill tunnel as subway stop makes perfect sense as well.

Doing something like this would be so huge to connecting downtown/Loring Park to S Minneapolis, in both street connections and tying land-use back together.

[Mdcastle]

I kind of wonder if you could stack the lanes in the tunnel- have say 5 lanes on top and 5 lanes on the bottom like the Yerba Buena tunnel in the bay area to reduce the overall width. Also, a minor point, I believe plans are still to move the ramp from I-35W north to I-94 east to the right, it would leave before the curve and pass under the on-ramp from Franklin.

[mister.shoes]

Only moderately related to the topic at hand (ok, not really related at all), but there are some killer photos of the Alaskan Way tunnel in this article.
http://gizmodo.com/something-called-the ... 1487090414

[woofner]

I'd say the article is highly relevant as an example of why it's inappropriate to assume tunneling costs in Seattle for projects here:

Bertha, the world's largest tunneling machine, churning through the rock and mud beneath Seattle, has hit a mysterious roadblock—so mysterious, it is only known for now as "the object."

The New York Times reports that the machine—300 feet long and 5 stories tall—has ground to a halt. Built precisely not to be stopped by, well, by just about anything, Bertha has apparently met her match. But what exactly is it? "Something unknown, engineers say—and all the more intriguing to many residents for being unknown—has blocked the progress of the biggest-diameter tunnel-boring machine in use on the planet," the NYT writes.

It is something the managers on site "still simply refer to as 'the object.'"

There is, of course, an element of risk in any underground project. But there is much less risk when your bedrock is layers of compressed sand than when your bedrock is a twisted amalgam of volcanic rock permeated with fault lines.

[mattaudio]

^that's what I like to hear, woonerf!

[RailBaronYarr]

Someone call Zelle and get this prioritized ASTAT.

[froggie]

(idly surprised I didn't catch the reboot of this forum, whenever it was)

Relating to Hennepin/Lyndale, here's another way to consider it:

[froggie]

(also posted on Streets.MN, as mister.shoes asked my opinion of his proposal there)

I like the overall concept of a more direct I-94 tunnel, though it'd be just as fantastically expensive as MnDOT's earlier proposal to expand the existing tunnel. It's location is not unlike "Line C" from the I-94 alignment studies: http://www.flickr.com/photos/ajfroggie/13088241504/

Some comments/concerns:

- I think there's more that would have to be cut-and-cover than you're thinking, especially north of I-394. This would be a major impediment to construction given the private lane (and large building) north of 394.

- I don't think this would have to be 5 lanes each way, but it'd likely have to be 4 lanes each way. A pair of 2-lane tubes each way (similar to the Fort McHenry Tunnel in Baltimore, MD) may be doable, with the rightmost tunnel expandable to 3 lanes in the future if needed.

- As this would still be a tunnel, "prohibited" trucks would still have to use your new surface route. As such, I don't think the roundabouts would fly. The lack of a direct connection from westbound 94 to the proposed surface route doesn't help either. Such trucks would probably follow 15th instead.

- The weird loop ramp from 3rd Ave to the westbound tunnel is unnecessary.

- Still like my idea of a "Lowry Square" instead of a traffic circle at the Hennepin/Lyndale confluence.

- Instead of the large traffic circle at Hennepin/Lyndale/Dunwoody, I'd make Lyndale a multi-way boulevard through the project area.