CHICAGO | River Point | 730 FT | 52 FLOORS

[Mr Downtown]

Originally Posted by ardecila

It is odd that many of the buildings over Union Station have plazas above street level. Boeing, 2 N Riverside, 10 S Riverside, etc. Virtually all of them step up from street level to some extent.

Surely you realize there are railroad tracks underneath all of those. So you automatically are 24-30 feet above the riverbank level before you can put down any decking support.

[harryc]

Jan 17

(from ABA)


(from CTA)

[BVictor1]

Lol...

This is going to be a 10 year thread (2007-2017).

Announcement to completion.

The time we spend.

[neverdone]

Originally Posted by harryc

Looks like no openings in that slab. Maybe the cantilever & portholes help with dissipating the Metra exhaust?

[harryc]

Originally Posted by neverdone

Looks like no openings in that slab. Maybe the cantilever & portholes help with dissipating the Metra exhaust?

That is correct.

[ardecila]

Originally Posted by Mr Downtown

Surely you realize there are railroad tracks underneath all of those. So you automatically are 24-30 feet above the riverbank level before you can put down any decking support.

Of course, but nobody's ever explained why the plaza decks need to be higher than the streets, which also cross the railroad tracks on structure.

The only thing I can think of is that the plaza decks need extra structural depth because they're supporting building loads.

[wierdaaron]

^Yeah, those pre-stressed steel girder things people were drooling over a few pages ago sure added a lot of height. If they weren't necessary, the roof itself would probably be pretty close to street level. Weird.

[wierdaaron]

Originally Posted by J_M_Tungsten

(To illustrate.)

[Rizzo]

Originally Posted by ardecila

Of course, but nobody's ever explained why the plaza decks need to be higher than the streets, which also cross the railroad tracks on structure.

The only thing I can think of is that the plaza decks need extra structural depth because they're supporting building loads.

It's because this is the only site on a curve. They aren't going to build a forest of columns like the other buildings with a ton of cast in place of formwork of a ton of different dimensions.

If there was a building on top, they could at least transfer the loads within the interior of the building, but it's a plaza.

It's cheaper to run a ton of longspan beams. They can support a ton of load with simple construction at a low cost. Probably makes Metra happy from a maintenance standpoint. It's the easiest and cheapest. Only problem is all that structural depth adds some elevation above street level. But there's always an architectural solution.

I suppose it's not ideal. But it's Lake Street....

[ardecila]

I was talking about buildings further south, like Boeing and 2 N Riverside.

I understand the situation at River Point pretty well; I think most of the design criteria there have been discussed in this thread at one point or another.

[harryc]

Jan 21


Jan 22


Jan 24

[pilsenarch]

Originally Posted by wierdaaron

(To illustrate.)

It isn't just the structural depth... the bottom of the structure is what, 4-6' above the bottom of the lake street viaduct structure...

[J_M_Tungsten]

It was probably purposely designed like that so they can keep better control over the site. The can close it off if need be. Also, I imagine a tunnel over railroad tracks would need to be secured to some extent.

[BVictor1]

Originally Posted by ardecila

Of course, but nobody's ever explained why the plaza decks need to be higher than the streets, which also cross the railroad tracks on structure.

The only thing I can think of is that the plaza decks need extra structural depth because they're supporting building loads.

One nice thing about the deck height is that the pedestrian at park level will be a lot close and personal with the El.

[Swicago Swi Sox]

I may also be that Metra (or whoever controls those tracks) have decided to change their requirements over the years. 25 years ago, when Boeing was built, they may have thought a certain overhead height would work out and have now found that it did not and are being more strict this time around. Similarly, it could also be that the trains require a higher overhead at this section of track due to a different speed or turn.

[ardecila]

Originally Posted by Swicago Swi Sox

Similarly, it could also be that the trains require a higher overhead at this section of track due to a different speed or turn.

That is the reason for the higher deck, at River Point.

The Metra tracks rise up between the Lake and Canal crossings. The deck height is set relative to the elevation at Canal and extended in a mostly flat fashion across the site. When that meets Lake Street, it hits above the deck of the Lake St viaduct.

(Metra train rising up, courtesy harryc)

[harryc]

[harryc]

Big Manitowac crane is gone.

[left of center]

Can't wait for this one to start rising!

Anyone take the MDW, NCS or MDN lines in to the Loop? How cool is it having the train move through that new tunnel? Once 150 N Riverside has work start on its own foundation, it will really compete with the SWS, BNSF and HC approach to Union Station from the south, which is all tunneled in from Polk Street. All told, that will be roughly 12 city blocks of Metra trackage that will be under street level and built on.

I'm a sucker for underground transportation infrastructure

[ardecila]

I think the tunnel is actually a downgrade for the Metra rider's experience... they once had a spectacular view of the Confluence and now they have a vista of concrete walls.

It's a slight win for the public at large, though, which will now have access to this riverbank when they didn't before.