DENVER | Transportation Thread

[Zmapper]

My latest back of the napkin sketch: http://goo.gl/maps/mmAj

Inspired by a comment on the Denver Post, the concept is to extend Colorado Blvd south to connect with Vazquez/Colorado Blvd. A new full parclo interchange would be constructed approximately 1/2 mile south of the existing Vasquez/I-76 Interchange. Such a project would allow for easier travel north and south east of I-25 without the need to drive on congested 2-lane rural roads.

[Cirrus]

Why bother removing the northbound ramp just to build a new one as part of the new interchange? Is something wrong with the existing ramp?

Money is tight. It would cost at least $10 million to demolish that ramp and then build a new one. You can make a case for extending CO Blvd and giving it an interchange, but I'm having trouble seeing the benefit of spending a lot of money to change a northbound ramp if nothing's wrong with it. It doesn't hurt anyone to veer right for the northbound exit 1/4 mile before the other movements.

[Zmapper]

I thought about it, but decided against keeping the ramp there for two reasons, Cirrus:

First, relocating the ramp is more user friendly, as it moves everything related to the Interchange to the interchange. I thought about keeping the ramp, but sooner or later a tourist from Oklahoma wanting to go west on I-76 will see the exit ramp for east, drive a 1/2 mile, wonder where in the heck the interstate is, and turn around.

The second benefit is that a relocation frees up space currently occupied by Vasquez Blvd for redevelopment. A decent sized location right next to the Interstate and close to major destinations would mean that a distribution center or a truck stop could fit there.

I dought relocating the NB ramp would cost all that much, considering that it is completely at ground with the exception of a 20' bridge over a canal.

[Cirrus]

It will cost that much, at least. It's not only the cost to remove the existing one, but also to build a new redundant one.

Selling the land for redevelopment could be a good reason to do it this way, but I'd want to have a buyer and a development plan lined up ahead of time, before agreeing to a large and otherwise unnecessary expense.

[DenverTrans]

Originally Posted by LAM

DenverTrans, this photo you posted is quite beautiful. However, considering RTD would be building it; and it is not the early 1900's; and we don't have a city filled with corporate robber barons, or Tammany Hall, or the likes of that; I doubt anything in Denver would ever look like that. Besides, one bridge does not an elevated rail line make. Not that we can't hope.

http://www.skyscrapercity.com/showthread.php?t=304129


I know -- examples like this are:

1. In Europe
2. A retrofit of an historic viaduct

By the way, the Pershing Square cafe was a project of the Grand Central Partnership Business Improvement District, I think. Originally, there was nothing under the viaduct in that location.

The details do not really matter. The facade is just a skin. The structural system of the viaduct does not have to be masonry arches or steel girders (although those are still being built even today). Box beams can be beautiful too. And the reverse of this model also applies -- one can line a highway overpass with shops as has been done in Columbus, Ohio.

The question is whether urban viaducts can be beautiful in the current era since most people will admit that Paris, Vienna, and similar cities have quite charming elevated rail lines.

Incidentally, there was a time when the United States had no modern LRT systems. Today it is commonplace.

[LAM]

Originally Posted by DenverTrans

I know -- examples like this are:

1. In Europe
2. A retrofit of an historic viaduct

By the way, the Pershing Square cafe was a project of the Grand Central Partnership Business Improvement District, I think. Originally, there was nothing under the viaduct in that location.

The details do not really matter. The facade is just a skin. The structural system of the viaduct does not have to be masonry arches or steel girders (although those are still being built even today). Box beams can be beautiful too. And the reverse of this model also applies -- one can line a highway overpass with shops as has been done in Columbus, Ohio.

The question is whether urban viaducts can be beautiful in the current era since most people will admit that Paris, Vienna, and similar cities have quite charming elevated rail lines.

Incidentally, there was a time when the United States had no modern LRT systems. Today it is commonplace.

Another very cool photo. I have seen other uses of old viaducts where they do the infill under the arches. And, of course there is the Highline in NYC where they kept the rail viaduct and converted the top of it into a raised park.

Unfortunately, I think that an elevated rail downtown would tend to fill up the streets too much. In the same way that they do in Chicago.... And the noise. I know our light rail tracks are a lot quieter ... but still.

However...

...maybe we should look at these solutions for how we treat the area under highway viaducts like I-70. I think large highway viaducts are barriers between neighborhoods because the undersides are dark and scary. People don't want to linger and they are devoid of sunlight and plant life. And the streets underneath just don't work. It is still a black void. So, by filling the darkness with occupied offices and maybe even residences, it would become a street wall no different than a city street with buildings. There would need to be some serious sound mitigation between the highway and buildings below though.

Perhaps it could actually stitch together the neighborhoods again. Or, maybe I'm a little too optimistic.

[bcp]

denver, once again, sadly, has ripped out it's grit - this time it's the old metal viaducts.

[DenverTrans]

Originally Posted by LAM

Another very cool photo...

Unfortunately, I think that an elevated rail downtown would tend to fill up the streets too much...

...maybe we should look at these solutions for how we treat the area under highway viaducts like I-70....

Yeah, I don't know about through downtown either. If an elevated rail line had been designed in years ago, it could perhaps have run over an alley or through buildings mid block (as the High Line does). I think the better opportunity was with intercity rail and Union Station. It would have worked okay in the urban fabric.

I agree it makes sense to look at applications for better highway viaducts.

[bcp]

what's wrong with "filling up the streets too much"...in a city?

[LAM]

Originally Posted by bcp

what's wrong with "filling up the streets too much"...in a city?

I don't mind filling the streets with things like people, cars, and bicycles. But, a long linear building with a rail on top? It just seems like a bit too much to squeeze in there.

[DenverTrans]

Can't resist another one:


http://www.designbuild-network.com/p...a-gurtel2.html


http://www.designbuild-network.com/p...a-gurtel3.html

Again, running a train over the downtown street might not be the best option. I think the better question is to think about how an elevated grade separation might have been accomplished, leaving most options on the table. Probably too late for that now, but more feasible a few years back. Definitely was feasible in the Central Platte Valley.

[mr1138]

But if you're not gonna run it above the street itself, and are going to use something like an alley instead, then isn't what we've been building (dedicated alignment along a freight line thru the CPV) basically just as good functionally speaking? I've always thought that something like the West Line light rail through Lakewood is pretty much as good as any subway or EL train, it's just that in this case we happen to have a dedicated at-grade alignment (I'm not talking so much about where it shares the R.O.W. with 13th Ave. but more where it slips between the back side of houses/properties). Not that the architectural treatment of the above examples aren't really cool (because they are), but if we're gonna run it down an alley or some other non-street right of way, then does it really need to be grade separated from said alley in order to work?

[DenverTrans]

A grade separated rail line can run considerably faster in an urban context than an at-grade line. In the suburbs it is less important, because you can protect the crossings with gates to give priority to the train. In the city, that is not really possible, so the train has to proceed at a slower speed.

If the train is elevated, then at various points it has to interact with urban streets, and at those points, the design becomes key.

One of the biggest impacts is not the elevated structure, but rather the elevated stations, because they take up a lot more space.

It has always been recognized that rapid mass transit requires grade separation. Thus, subways, elevated trains, and flyovers at grade crossings start happening in the nineteenth century (take a look at Philadelphia's rail network). Many people imagined that the elevated trains would run through the big urban buildings mid-block, which solves the problem of having viaduct structures loom over the street. Ultimately, that did not happen for several reasons, but mostly related to the complexity of assembling the right of way, I think, followed by the adoption of automobile infrastructure instead of mass transit. The rapid transit that got built in the later 20th Century often was built in subways (Atlanta, San Francisco, Washington, Buffalo, LAX, etc). Some of the remaining elevated trains were torn down in the name of improving urban conditions, with the Second Avenue el being a prime example. And New York, Our Lady of the Subways, is still struggling all these decades later to build a subway under Second Avenue to replace it.

[SnyderBock]

That's a good point. Viaducts eventually have to be rebuilt. This can be a big problem. A subway tunnel should last much longer. If it's cut and cover subway, with a road deck topping it, it may need to be rebuilt sooner than an actually tunnel bore, but it could possible be done in sections, at night, without interruption to transit service. With a viaduct, it's hard to keep trains moving, when a chunk is torn out for rebuilding!

If Denver ever opts to build urban grade-separate mass transit, I hope they opt for the more expensive up front option of subway. I'd like to see streetcars first though. One concern, is if they build streetcars over an area that in the future they need to build a cut and cover subway. Perhaps they could squeeze the subway tunnel in under the actual street lanes, without having to also be under the streetcar line? I'm thinking mainly Colfax and Broadway.

[bunt_q]

Okay let's quit looking at trains from the 1910s. Let's look at renderings from the 2010s. This is what elevated rail means today. And forget any talk of doing it better - it's already a $5 billion project - this is what we'd get.

First a before/after from the EIS:





A few more from Honolulu Weekly (and the one with the graffiti added, that was added by the AIA chapter... Architects leading the fight against rail, haha.). Anyways:









So yeah... I think we have better options in Denver. I can't think of a single instance where this would be acceptable.

[SnyderBock]

Another tower crane at DUS redevelopment

Source: http://www.earthcam.com/client/kiewit/?cam=pano


Also, initial work has begun on Commuter Rail Terminal
IMA tower crane is also visible in this shot

Source: http://www.earthcam.com/client/kiewit/?cam=pano

Sorry these photos are large!

[EngiNerd]

I cringe every time I see that Honolulu elevated rail...BUT, that would probably be bulkier than needed in Denver because of the high wind and earthquake loads they have in Hawaii....still, I doubt one here would be a whole lot less ugly.

And yes you can make it out of steel, which is lighter, but exposed steel like that doesn't last. No matter how you protect it, an exposed steel structure needs constant and costly maintenance.

[Cirrus]

Originally Posted by bunt_q

And forget any talk of doing it better - it's already a $5 billion project - this is what we'd get.

Not that I necessarily disagree, but how did we afford these?







All images from Google Street View.

[bunt_q]

Those are regular bridges with some added design elements. There's nothing fundamentally different about them from the pictures I posted except that they aren't elevated lines, they are perpendicular crossings. Turn that picture 90 degrees and elevate the structure parallel with the road underneath it and it looks completely different.

This isn't a case of roads getting a sweeter deal than transit. We hate our elevated road too.

Better example would be, "why are we willing to pay to depress I-70?". And when it comes time grade separate our transit, I'll be making the argument that it's worth every penny to go down if the only other alternative is to elevate it.

[LAM]

Originally Posted by Cirrus

Not that I necessarily disagree, but how did we afford these?

Pictures deleted to save room.

All images from Google Street View.

I'm just guessing, but I believe that these bridges added a little extra stuff to the sides which is probably not that expensive when spanning a short distance on a really wide bridge that people drive under for 1 second or so. But, narrow it up and make it much longer and the cost as a percentage of the bridge would likely increase quite a bit. But, that are good examples of how you can add a little extra to make a very dull thing look nice.