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

chief56 · #1 Posted **Apr 19, 2017, 12:40 PM**

Quote:

Originally Posted by petey2428

I thought the bedrock is pretty high in new york, so you don't have to go down deep unless it's for rock anchors. For example, 1WTC in New York sits pretty much on bedrock. You don't have that condition in Chicago.

PT construction is the standard for high rise residential construction in Chicago. You can curve the tendons to avoid conflict with conduits/pipes/etc.

Allows for less reinforcing in the slab, resulting in thinner slabs and the heigher floor to ceilings people want in residential buildings.

An easy way to tell where bedrock in NYC is look where all the tall buildings are. Southern end of the island and middle.

BVictor1 · #2 Posted **May 1, 2017, 7:07 AM**

04/28/17

I'm not exactly sure what the blue poles are about.

kayosthery · #3 Posted **May 1, 2017, 11:58 AM**

Quote:

Originally Posted by BVictor1

04/28/17

I'm not exactly sure what the blue poles are about.

The blue poles hold a horizontal life line. The workers can attach a lanyard or retractable to the line when exposed to a fall; usually the carpenters installing the deck formwork.

BVictor1 · #4 Posted **May 1, 2017, 2:13 PM**

Quote:

Originally Posted by kayosthery

The blue poles hold a horizontal life line. The workers can attach a lanyard or retractable to the line when exposed to a fall; usually the carpenters installing the deck formwork.

Interesting.....

And I'm guessing that lip-like formwork prevents the poles from being permanent and they'll slide back down through the floor.

harryc · #5 Posted **May 1, 2017, 3:13 PM**

Quote:

Originally Posted by BVictor1

Interesting.....

And I'm guessing that lip-like formwork prevents the poles from being permanent and they'll slide back down through the floor.

They are raised as the floors set, the hole keeps them from getting stuck in the concrete. On some sites the holes have been filled in after the floors above have been completed.

City Wide · #6 Posted **May 1, 2017, 4:03 PM**

Quote:

Originally Posted by kayosthery

The blue poles hold a horizontal life line. The workers can attach a lanyard or retractable to the line when exposed to a fall; usually the carpenters installing the deck formwork.

Not that it matters in the whole course of events, but why have at least one of the poles in the middle of the slab, fall away from the edges.
Strange that none of the photos show any one actually connected to the poles, even the ones somewhat close to the edge.
Unless these poles are attached to something on the floor under the one actually being worked on, that would mean that the poles aren't attached to anything other then the form work, 3/4" plywood, which doesn't seem like that big of a support.

kayosthery · #7 Posted **May 1, 2017, 4:37 PM**

Quote:

Originally Posted by City Wide

Not that it matters in the whole course of events, but why have at least one of the poles in the middle of the slab, fall away from the edges.
Strange that none of the photos show any one actually connected to the poles, even the ones somewhat close to the edge.
Unless these poles are attached to something on the floor under the one actually being worked on, that would mean that the poles aren't attached to anything other then the form work, 3/4" plywood, which doesn't seem like that big of a support.

The slab formwork in the picture is complete for those respective slabs. The handrail is in place where McHugh is breaking the pour between the West and East portions of the building. While the work was in progress those blue poles were actually in a more "useful" position.

As I'm looking at the pics more closely, they may not be an actual horizontal lifeline, but rather just a taller tie-off point to control fall distance.

The poles are actually anchored into the slabs below, as Harry mentioned. They are pulled up after each pour and the slab is filled in, or they exist in a mechanical opening that's in the same place on each slab.

City Wide · #8 Posted **May 2, 2017, 4:37 PM**

Quote:

Originally Posted by kayosthery

The slab formwork in the picture is complete for those respective slabs. The handrail is in place where McHugh is breaking the pour between the West and East portions of the building. While the work was in progress those blue poles were actually in a more "useful" position.

As I'm looking at the pics more closely, they may not be an actual horizontal lifeline, but rather just a taller tie-off point to control fall distance.

The poles are actually anchored into the slabs below, as Harry mentioned. They are pulled up after each pour and the slab is filled in, or they exist in a mechanical opening that's in the same place on each slab.

I'll be the first to acknowledge that this 'blue pole' issue is a very minor point in a large, complex, interesting and important project. But, as someone who's been looking at and sometimes working at construction sites for many, many years, I'm always interested is seeing the ever changing methods used to build. Its a dance performance that takes years to complete, and it has lots of different acts in the dance..

Anyways, if these poles are actually two floors tall and we only see the top half and the bottom is attached to the last completed pour, then the poles position isn't going to change floor to floor. I assume as one floor is completed and the concrete is reasonably firm, the pole would be pulled up through the hole in the concrete, somehow anchored, and the formwork for the next floor built around this pole. And so on during the construction climb.

Meaning, that after a pour is complete, they can't just be moved out of the way for awhile, unless they are pulled out of their hole.

But I'm not so sure they are part of any fall protection system, time will tell. They aren't regularly spaced, they aren't always on the edge (where falls take place) and so far none of the photos show anyone connected to them. But I don't have any idea what they are for; and if they are in fact anchored one floor below, (photos please if possible) then being part of a safety system makes as much sense as anything else; at least until there's more evidence one way or another.

harryc · #9 Posted **May 2, 2017, 10:41 PM**

Apr 24

Doka Forms

n.b. break off heads on the bolts - just tighten until they pop off (at a pre-determined torque).

Tie off pole for safety lines - used while constructing the deck.

harryc · #10 Posted **May 1, 2017, 5:36 PM**

Quote:

Originally Posted by City Wide

Not that it matters in the whole course of events, but why have at least one of the poles in the middle of the slab, fall away from the edges.
Strange that none of the photos show any one actually connected to the poles, even the ones somewhat close to the edge.
Unless these poles are attached to something on the floor under the one actually being worked on, that would mean that the poles aren't attached to anything other then the form work, 3/4" plywood, which doesn't seem like that big of a support.

These Union folk are pretty anal about their safety measures - often both the GC and the Union will have safety inspectors on site. I will dig up some shots of them using the safety harnesses and fall prevention, when working below grade on the foundation mat.

Rocket49 · #11 Posted **May 1, 2017, 6:21 PM**

Quote:

Originally Posted by harryc

These Union folk are pretty anal about their safety measures - often both the GC and the Union will have safety inspectors on site. .

If you're using "anal" in a derogatory sense, I would have to disagree with you.

Having a very safe worksite should be a prime goal of any construction project.

harryc · #12 Posted **May 1, 2017, 6:30 PM**

Quote:

Originally Posted by Rocket49

If you're using "anal" in a derogatory sense, I would have to disagree with you.

Having a very safe worksite should be a prime goal of any construction project.

No - short for anal-retentive - not derogatory, fastidious just doesn't seem to convey the correct feel.

They follow the rules even when common sense says otherwise (e.g. rigging safety lines and wearing fall protection when working at the bottom of a pit).

I suspect the injury rate on union sites is well below that of their more ... pragmatic ... competitors..

Skyguy_7 · #13 Posted **May 1, 2017, 6:31 PM**

^^There's safety, and then there's five safety enforcers with clipboards watching one man work, which is what Harry is likely referring to. Too many "safety" regulations actually hinders construction and often times, can make working more hazardous.