A Few Questions about How Skyscrapers are Erected

[myshtern]

I've always been puzzled by a few things in skyscrapers.

1. How is the glass installed on all glass high rises? On some high rises I see scaffolding going all the way up. On others there is no scaffolding so I assume it is installed from the inside of the building (i.e. Burj Dubai).

How is it installed so that you can't see things that are unappealing such as utilities that travel in between floors? Is the inside of that glass area frosted?

2. How are glass high rises insulated? Is there any insulation used in between floors at the exterior?

3. Where do those damn cranes go? If a crane sits at the center of a building like I see with the Philly Comcast tower, I assume there is a square void through the entire building??? How is the crane disassembled with the building all around it? Is that void then later blocked up and used as ventilation shaft???

Thanks :yes:

[harryc]

I've always been puzzled by a few things in skyscrapers.

1. How is the glass installed on all glass high rises? On some high rises I see scaffolding going all the way up. On others there is no scaffolding so I assume it is installed from the inside of the building (i.e. Burj Dubai).

How is it installed so that you can't see things that are unappealing such as utilities that travel in between floors? Is the inside of that glass area frosted?

2. How are glass high rises insulated? Is there any insulation used in between floors at the exterior?

3. Where do those damn cranes go? If a crane sits at the center of a building like I see with the Philly Comcast tower, I assume there is a square void through the entire building??? How is the crane disassembled with the building all around it? Is that void then later blocked up and used as ventilation shaft???

Thanks :yes:
Glass installed:
They use a small crain/hoist from the floor above, there is a good pic of this buried in the trump thread.
Unappealing:
Most if not all electric, Data, Air, water, and sewage is in the core. Curtain wall means just that, it is a curtain.
Insulated:
Not very well ;-) double pained glass.
Cranes go away.
The craines are a stack of segments, the exterior ones lower themselves down. I have always assumed the interior ones pull the segments out the top then lower them down.

[theWatusi]

The crane for the Comcast Center is mounted on the top of the core (there is no tower that goes all the way to the ground like the crane on the exterior)

When it is no longer needed it will be removed by helicopter

[Coldrsx]

"How is it installed so that you can't see things that are unappealing such as utilities that travel in between floors? Is the inside of that glass area frosted?"

if you look closely you will usually see the spandrels on towers which are the same color but typically not see through...in other words you will have your 6 foot curtain wall with a 2-3' spandrel hiding the slab and utilities.

2. How are glass high rises insulated? Is there any insulation used in between floors at the exterior?

many use high R-value (>8) glass and different sorts of peel and stick for moisture/heat transfer, but also they use heated air along the spans of the windows to control heating and thereby creating a sort of "insulation" through that.

3. Where do those damn cranes go? If a crane sits at the center of a building like I see with the Philly Comcast tower, I assume there is a square void through the entire building??? How is the crane disassembled with the building all around it? Is that void then later blocked up and used as ventilation shaft???

depends on the tower...but many condo towers have designed that space for HVAC or just fill in the gaps afterwards.

[Canadian Mind]

how do the utilities go between floors? do they drill holes in the floors after pouring concrete, or are there gaps in the form for shaping utility holes?

[Coldrsx]

how do the utilities go between floors? do they drill holes in the floors after pouring concrete, or are there gaps in the form for shaping utility holes?

they have plastic pipes put into the slabs before the pour so they are there ready once the concrete sets...but they also "core" if they need to.

[AltinD]

The crane for the Comcast Center is mounted on the top of the core (there is no tower that goes all the way to the ground like the crane on the exterior)

When it is no longer needed it will be removed by helicopter

Is that ever used ... I mean the helicopter?

From what I have seen and heard: They just build on top a small portable crane to bring down on the roof the dismantled pieces of the big one. Those pieces are either send down by the lift or that small crane is used.

However, here in Dubai for towers up to around 400 - 450 ft tall, they usually use a mobile crane with a very long expandable arm and a long broom installed on top of it.