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

[Steely Dan]

Originally Posted by chris08876

Can someone explain to me why this link above was deleted from the Chicago construction complilation?

we don't double post stuff when it comes to chicago projects.

ALL images, articles, discussion, opinions, etc. regarding vista tower belong in this thread, not the chicago compilation thread.

it keeps things cleaner and more organized.

[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?

[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.

[LouisVanDerWright]

First they make this:



Then they lower the next longest and skinniest size in (note 12' sprayed on the outside and 11' 3" on the inside sleeve):



Then finally they will lower in the super huge sleeve which is probably like 10' 6" in diameter into the big hole they just made:

[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.

[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

[Steely Dan]

Originally Posted by Kumdogmillionaire

This may be a dumb question but couldn't someone get the bends by going down a hole like that as well?

no, these are open caissons. they aren't pressurized like the ones they used to use to build bridge foundations underwater.

the bends is caused by an extreme and sudden depressurization that causes dissolved gas bubbles to come out of solution in a person's blood.

the air pressure differential between being at grade or at the bottom of a 100' foot hole (or even a 1,000' hole) is nowhere near enough to create the necessary depressurization to cause the bends, regardless of how fast one transfers between the two. hell, thousands of people every single day rocket 1,400' up to the top of the sears tower in those super fast elevators without getting the bends.

[Skyguy_7]

Originally Posted by 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?

There's no set lunch time. Different trades take their breaks at different times, so you'll always have activity throughout the day. My guys take their "lunch" at 9:30! Crazy union rules..

[vexxed82]

Originally Posted by Skyguy_7

There's no set lunch time. Different trades take their breaks at different times, so you'll always have activity throughout the day. My guys take their "lunch" at 9:30! Crazy union rules..

Interesting, thanks! Just got back form the site. Got some cool stuff. Tons to edit...

[vexxed82]

The first of many site visits. Should be a fun ride.



























Have a few more here

[Steely Dan]

^ outstanding pics!

[intrepidDesign]

Bad ass dude. Thanks and keep em coming!

[excel]

That drill is nuts!

[Kumdogmillionaire]

Thanks Steely for the knowledge bomb!

[skybuilder]

I don't usually post but I was a tech engineer for 5 years and worked on many caisson jobs with case and revcon. Basically I was the surveyor on site. Caisson work was really fun/hard. I didn't work on rock caissons but they work the same. The bigger liners you see depend on site issues. Loose soil high water table sandy unstable ground etc. typically the largest and first liner is to hold back the first 10 to 20' of soil around the drill bit. If water is present it's a hole by hole determination as to how deep to go. Basically no set standard on how the liners are used. They drive the liners into the hole by disconnecting the bit from the kelley bar and using a bar to essentially screw the liner in.

[kolchak]

What a great shot of Aqua and the site together.

[Shwayze1994]

Originally Posted by skybuilder

I don't usually post but I was a tech engineer for 5 years and worked on many caisson jobs with case and revcon. Basically I was the surveyor on site. Caisson work was really fun/hard. I didn't work on rock caissons but they work the same. The bigger liners you see depend on site issues. Loose soil high water table sandy unstable ground etc. typically the largest and first liner is to hold back the first 10 to 20' of soil around the drill bit. If water is present it's a hole by hole determination as to how deep to go. Basically no set standard on how the liners are used. They drive the liners into the hole by disconnecting the bit from the kelley bar and using a bar to essentially screw the liner in.

Really interesting.

[BVictor1]

10/07/16

I didn't feel like editing these.