CHICAGO | St. Regis Chicago (Vista) | 1,191 FT | 101 FLOORS

[harryc]

Originally Posted by LouisVanDerWright

Notice how you never just see a giant cassion sleeve like the ones delivered the other day just sticking 3/4 of the way out of the ground? You will never see that because the equipment couldn't possibly work with a 100' long sleeve all at once. What they do is drill in a 22' wide by 25' long one, then lower a 50' long by 21' 3" sleeve into the existing hole so only 25' is sticking out. Then they telescope that one all the way into the hole and then they bring out a 75' long by 20' 6" one and drill that all the way in. THEN comes the big boy which is say 20' even wide and 100' long and drill that all the way down. Once they've "telescoped" to the right depth they bust out the rock grinders, make their socket, and then lower a permanent galvanized corrugated sleeve all the way into the hole with the rebar cage in the middle a pour away.

I actually wondered about that a long time myself, how do they keep reusing the sleeves? How do they get them out? Why do you never see a super long one just like halfway drilled into the ground? Then I watched them working at this site the other day and saw them dropping a medium sized one into a larger hole and was like "gotcha". I suggest going down to watch this site, it's immensely impressive. Watching a rig like this torque the big sleeves that have hundreds of square feet of surface area against thick Chicago mud is quite a sight.

Great explanation !

For those sleeves that just don't want to come back up ...

A block and tackle sized for the job (on right) - CASE at Prentice 2015.

[City Wide]

Originally Posted by LouisVanDerWright

Notice how you never just see a giant cassion sleeve like the ones delivered the other day just sticking 3/4 of the way out of the ground? You will never see that because the equipment couldn't possibly work with a 100' long sleeve all at once. What they do is drill in a 22' wide by 25' long one, then lower a 50' long by 21' 3" sleeve into the existing hole so only 25' is sticking out. Then they telescope that one all the way into the hole and then they bring out a 75' long by 20' 6" one and drill that all the way in. THEN comes the big boy which is say 20' even wide and 100' long and drill that all the way down. Once they've "telescoped" to the right depth they bust out the rock grinders, make their socket, and then lower a all the way into the hole with the rebar cage in the middle a pour away.

I actually wondered about that a long time myself, how do they keep reusing the sleeves? How do they get them out? Why do you never see a super long one just like halfway drilled into the ground? Then I watched them working at this site the other day and saw them dropping a medium sized one into a larger hole and was like "gotcha". I suggest going down to watch this site, it's immensely impressive. Watching a rig like this torque the big sleeves that have hundreds of square feet of surface area against thick Chicago mud is quite a sight.

Lets see if I've got this right----drive a large diameter sleeve into the ground as deep as possible. (I assume that the friction between the sleeve and the ground limits the depth of this drive, bigger diameter=more surface area rubbing against the sleeve=shorter depth, small diameter = less friction = greater depth) then drill and remove the debris from the center of the first sleeve. Repeat these steps with a slightly narrower sleeve but of course it will drive deeper since the top section is not in contact with any dirt.
Then at some point in time a "permanent galvanized corrugated sleeve" is put in the full depth hole, a rebar cage is fit into the permanent sleeve which gets filled up with concrete.
Question, I've only ever seen this type of caisson construction done with 2 sleeves. Is this because 2 sleeves gets one down 100' or so, but if needed this principal of what you call telescoping could be done with as many sleeves as needed.
I have never seen a "permanent galvanized corrugated sleeve" why bother with the cost of galvanizing and corrugating? This last sleeve is just a form for the concrete, rust won't be a problem.
I assume that the reason for adding this permanent sleeve/concrete form/ and not just leaving the drilling sleeves in place must be cost. The drilling sleeves look major league compared to the permanent sleeve
After the permanent sleeve is filled, or maybe as it is being filled, are the drilling sleeves removed and the space they took up backfilled with dirt or grout?

[Swicago Swi Sox]

Originally Posted by City Wide

Augars to extract the soil



Lastly, are the piers/rebar actually mechically attached to the bedrock, as in someone goes down into the hole and glues a pin into the rock, or are there enough cracks and fissions in the rock that the wet concrete can 'key' into?

The Rebar is not mechanically fastened into the rock. The Drill bit creates enough keying action. Depending on what kind of capacity you need (i.e. usually set by uplift/tension capacity) sets how far the caisson needs to be socketed into the rock. These days they really try to avoid sending a human to the bottom of these holes.

[vexxed82]

Thinking of heading down to the site for some photos. Stupid question - but does the whole crew break for lunch at a fixed time? Or is there ALWAYS action going on-site?

[Kumdogmillionaire]

Originally Posted by Swicago Swi Sox

The Rebar is not mechanically fastened into the rock. The Drill bit creates enough keying action. Depending on what kind of capacity you need (i.e. usually set by uplift/tension capacity) sets how far the caisson needs to be socketed into the rock. These days they really try to avoid sending a human to the bottom of these holes.

This may be a dumb question but couldn't someone get the bends by going down a hole like that as well? Seems hella dangerous beyond just the whole sending someone down a metal tube 100 feet down thing

[HiRiser]

Originally Posted by City Wide

Augars to extract the soil


Maybe some of you deep diggers in Chicago can help me----why do some of the cessions have just the outer sleeve and others also have a separate smaller inner sleeve? I've noticed this in other cities (FMC building in Philly) so I guess its common practice.
Do the sleeves stay in the ground or get pulled out as the concrete fills up the hole?
Lastly, are the piers/rebar actually mechically attached to the bedrock, as in someone goes down into the hole and glues a pin into the rock, or are there enough cracks and fissions in the rock that the wet concrete can 'key' into?

Wow, that is a friggin awesome photo showing the scale of these cassions.

[harryc]

Originally Posted by photoLith

What tower is that and is it just a proposal?

Crews are already packing the site.



project is above ground.

[vexxed82]

Judging by Vista's latest issue of "No Parallels" we *only* get one angled column in the lobby area

[Ned.B]

^That's consistent with Officeworker's second to last photo from yesterday of the in progress formwork

[ithakas]

Taken moments ago

[harryc]

Dec 4

[aaron38]

Originally Posted by harryc

Dec 4

From the rendering it looks like the first inflection point is 12 floors above that big balcony on the middle tower. So the slope will change now.

[kayosthery]

Originally Posted by aaron38

From the rendering it looks like the first inflection point is 12 floors above that big balcony on the middle tower. So the slope will change now.

Floor plate of 23 is a narrow point on the high-rise. Walls from 23 to 24 are sloping outward now.

[BVictor1]

01/11/18







01/12/18







01/13/18

[donnie]

Feels just like yesterday they were pouring the foundation!

Awesome pics, thnx

[LouisVanDerWright]

Seriously though, without the city v city, I love how beefy most Chicago supertalls are. With the exception of 2 Pru which is only a metric supertall anyhow, this will basically be the most anorexic supertall in the skyline and it's still a beast. There's just something more exhilarating about watching them build beefier buildings, like that Index tower in Dubai that's like the size of Chase Tower, but as tall as Vista will be. The stump of this tower is similarly girthy, it's impressive to watch.

[Notyrview]

It's true, they're very impressive to watch uc.

it's all about variety anyway. all skinny isn't good, all yuge isn't good.

[harryc]

Jan 27

[Notyrview]

Woo woo woo, i like it, looking greenish.

[left of center]

Originally Posted by Notyrview

Woo woo woo, i like it, looking greenish.

I'm liking it too, although it looks pretty blue to me. Would've definitely preferred that it was a lot greener than it is, but this color isn't too bad... its a nice dark shade, which should differentiate it from the surrounding LSE buildings which have a lighter shade of blue (Coast, Shoreham, Regatta, etc.)