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View Full Version : How are tower cranes attached to buildings?



KevinFromTexas
Oct 10, 2007, 4:54 AM
This was a question posed by another forumer, and I've sort of wondered myself. How are tower cranes attached to buildings? They appear to have some kind of bracket that reaches out from the shaft of the tower crane and latches onto the skeleton of the building. Anyone know exactly how they are attached and where exactly? Floorplates or columns.

Austin55
Oct 11, 2007, 2:50 AM
This was a question posed by another forumer, and I've sort of wondered myself. How are tower cranes attached to buildings? They appear to have some kind of bracket that reaches out from the shaft of the tower crane and latches onto the skeleton of the building. Anyone know exactly how they are attached and where exactly? Floorplates or columns.

Arent they attached to the floorplates And the columns? but how does that move up?

KevinFromTexas
Oct 11, 2007, 3:58 AM
The tower crane's shaft doesn't move up. Only the top of the crane moves up when it's time to raise the crane. A jack raises the top of the crane and a new piece of tower shaft is slid in and bolted into place. The jack raises up another level (up to the new piece of shaft) and the process continues until the desired height is achieved. But I'm wondering how exactly they attach to the concrete without damaging it. That was the original question posed by another forumer, how are the brackets attached without chewing up the concrete.

dallasbrink
Oct 11, 2007, 5:22 AM
how do they move up the cranes on the super talls that rise with the building inside the building and how do they remove the cranes from the top of them?

The Jabroni
Oct 11, 2007, 4:12 PM
This has been a question that's been boggling my mind for a long time. I also want to know that once they're done construction, how do they take down the crane, especially at very tall heights?

cbotnyse
Oct 11, 2007, 6:14 PM
This has been a question that's been boggling my mind for a long time. I also want to know that once they're done construction, how do they take down the crane, especially at very tall heights?This is what I am wondering. In Chicago, I've seen other cranes come in to take down cranes, but that was on a mid-rise. How do you get down the Trump crain once its topped off? or the Spire crane????

MayDay
Oct 11, 2007, 6:50 PM
From wikipedia:

A tower crane is usually assembled by a telescopic crane of smaller lifting capacity but greater height and in the case of tower cranes that have risen while constructing very tall skyscrapers, a smaller crane (or derrick) will sometimes be lifted to the roof of the completed tower to dismantle the tower crane afterwards.

From what I understand, some cranes (likely the smaller/derrick) can be dismantled into pieces/parts that are small enough to fit in a freight elevator. That's likely what they used to remove the crane seen here (Key Tower under construction):
http://www.clevelandskyscrapers.com/cleveland/keytop1.jpg

theWatusi
Oct 11, 2007, 11:22 PM
how do they move up the cranes on the super talls that rise with the building inside the building and how do they remove the cranes from the top of them?

Only the top of the crane moves in this case also. The shaft of the crane is inside of the core (the base is at the bottom) See pictures of the FT to illustrate this

KevinFromTexas
Oct 13, 2007, 2:10 AM
I posted a very comprehensive thread in the Texas section with photos and video of how they raise and lower tower cranes. Amanita, our resident forum crane goddess, also helped out with the info. See the link below.
http://forum.skyscraperpage.com/showthread.php?t=135432

harryc
Oct 13, 2007, 2:14 AM
http://lh5.google.com/harry.r.carmichael/Rv2zzT6-WAI/AAAAAAAAHMk/-v7p8m0TNl4/P1040692.JPG?imgmax=640

http://lh3.google.com/harry.r.carmichael/Rv2z0z6-WBI/AAAAAAAAHMw/Uncf8vHUn7I/P1040699.JPG?imgmax=640

KevinFromTexas
Oct 13, 2007, 2:17 AM
Ha, well, here's a little photo info about how tower cranes are attached.
I took this picture back in July of the construction of San Antonio's Grand Hyatt hotel.
I took this picture from the Tower of the Americas of the hotel's top during construction.
If you pan over to the right you can see the braces I'm talking about which anchor the crane to the building's skeleton.
I'm still wondering how these are attached though without damaging the concrete.
http://i20.photobucket.com/albums/b234/KevinFromTexas/San%20Antonio/SanAntonioPano1.jpg

harryc
Oct 13, 2007, 2:18 AM
I posted a very comprehensive thread in the Texas section with photos and video of how they raise and lower tower cranes. Amanita, our resident forum crane goddess, also helped out with the info. See the link below.
http://forum.skyscraperpage.com/showthread.php?t=135432

Impressive.

harryc
Oct 13, 2007, 2:24 AM
Pieces on the ground.

http://lh4.google.com/harry.r.carmichael/Ru8wujpq-qI/AAAAAAAAF5w/FiRLUSmYkDg/P1030283.JPG?imgmax=640

Installed.

http://lh5.google.com/harry.r.carmichael/RwF52T6-jdI/AAAAAAAAJXI/O66Jy-fDOlk/P1040878.JPG?imgmax=512

This allows the crane to put in - or take out - sections of tower, raising or lowering itself.

harryc
Oct 13, 2007, 2:25 AM
http://lh4.google.com/harry.r.carmichael/RtLPIG-1l7I/AAAAAAAAE7Y/LR1s6cLjDVo/P1020026.JPG?imgmax=640

KevinFromTexas
Oct 13, 2007, 3:12 AM
Cool, thanks for the pictures. I'm guessing they're just bolted into the concrete?

Kelvin
Oct 13, 2007, 4:37 PM
Generally speaking a crane derives it's lateral support by, as noted previously, by use of horizontal ties to the building frame. The engineer who designs the building does not account or provide these measures -- rather that task is given to the general contractor or crane designer.

They in turn offer a means of support, including drawings and calculations, to the engineer who reviews it for compliance with their design.

All this is done before the crane goes up and so when formwork is put together, the contractor will then place special embedments behind the forms that get cast into the concrete (one could also detail special attachments in a steel frame too) and then are available to the crane when it gets to that point.

The point of attachment is usually at the slab (rather than the column) for a couple of reasons - 1. the column face is often further back than the edge of the slab making it the easiest place to connect to, and 2. placing lateral load (from the crane tower) is generally not well received by the engineer (it could make his column push out and deform, crack, or buckle - esp. with "green" concrete). Slabs on the other hand are especially well suited to picking up and distributing lateral loads from external elements.

When the crane is disassembled and the ties removed, the anchors can be grouted over.

harryc
Oct 13, 2007, 5:13 PM
Generally speaking ........ the anchors can be grouted over.

Thank your Kelvin !

Anchor on concrete ( 300 N LaSalle - Chicago )

http://lh5.google.com/harry.r.carmichael/RnA89uAe-9I/AAAAAAAAKLs/oekw9xWpymY/IMG_9771.jpg?imgmax=640

dallasbrink
Oct 15, 2007, 6:05 PM
ok, on these super tall building where the crane climbs with the floors and is attached to the floors i guess, how do they get those cranes down. Like on the Trump Tower in Chicago, how will they get those down?

MayDay
Oct 15, 2007, 6:32 PM
Slow down, switch to de-caf, and re-read:

A tower crane is usually assembled by a telescopic crane of smaller lifting capacity but greater height and in the case of tower cranes that have risen while constructing very tall skyscrapers, a smaller crane (or derrick) will sometimes be lifted to the roof of the completed tower to dismantle the tower crane afterwards.
...........

From what I understand, some cranes (likely the smaller/derrick cranes) can be dismantled into pieces/parts that are small enough to fit in a freight elevator. That's likely what they used to remove the crane seen here (Key Tower under construction):

http://www.clevelandskyscrapers.com/cleveland/keytop1.jpg
..........

MayDay
Oct 15, 2007, 6:40 PM
This is a pretty good "Cranes 101" from ALL - a company based in Cleveland:

http://allcraneloadcharts.com/pdfs/ALL_Erection_Equip_Guide.pdf

dallasbrink
Oct 15, 2007, 8:52 PM
still didn't answer my question.

I need visual examples or im not going to get it.

antinimby
Oct 16, 2007, 10:13 PM
How does the crane operator get up into the cab to operate the crane each day?

KevinFromTexas
Oct 17, 2007, 3:34 AM
How does the crane operator get up into the cab to operate the crane each day?

The tower crane shaft has a ladder that winds up the center of it. If you look closely at the photos posted above, you can see them. When a crane is standing alone on a construction site, the crane operator climbs the ladder to the operator's cab. Once the building starts to climb and the crane with it, the crane operator can use the construction elevator instead, which is attached to the side of the building much like the crane is. Then the operator can just climb into the tower crane shaft to the last few feet to the cab.

cbotnyse
Oct 17, 2007, 4:12 PM
still didn't answer my question.

I need visual examples or im not going to get it.I agree those pictures do not illustrate how a tower crane is lowered from a supertall.

MayDay
Oct 17, 2007, 11:58 PM
I'll try to simplify this:

http://www.clevelandskyscrapers.com/cranediagram.jpg

Crane A is assembled and jacked up (through a variety of ways) to the height required to build the tower structure.

Once Crane A is no longer needed, the construction crew uses Crane A to hoist Crane B to the roof, where it's secured. Crane B is used to dismantle Crane A and lower the pieces/parts to the ground.

Once Crane B has dismantled Crane A, Crane B either hoists Crane C to the roof *OR* Crane C's parts are placed in an elevator (The model that's Crane C can usually be broken down into parts that small) and sent up to the roof, where it is then used to dismantle Crane B. Once Crane C is no longer needed, it's dismantled and the pieces/parts are sent down via the elevator.

This photo, although it's on the ground is a good example of a Crane B being used to assemble/dismantle (either or) a Crane A. I really can't think of how I could make this any easier to understand, folks:

http://www.clevelandskyscrapers.com/avedist082707.jpg

dallasbrink
Oct 21, 2007, 7:15 AM
ooooo, that makes since.

Amanita
Oct 21, 2007, 6:11 PM
Check my dismanting picture sequence in the other thread somebody posted the link to. That's one way to get a Tower crane down.
I myself was not 100% sure how they rigged up the external supports for crane towers pictured here. Due to the relative lack of very tall buildings here, it's not something I've seen up close. I did have one fellow PM me asking, because he was worried about moving into a condo with damage to the ceiling left by the crane tiebacks.
I assured him that he won't have anything to worry about- whatever the securing method used, no developer or builder in their right mind is going to hand off a damaged unit to a buyer, with "crane marks" left all over the walls, floor, or ceiling. Can you imagine how many pissed off tenants there would be? Oww.

Since somebody's asked how operators get up into the crane, I'm surprised nobody's asked about bathroom breaks yet:)
Well, here's the short, sweet, and blunt of it. You want a bathroom break? You climb back down the tower. However, if the operators get really busy or don't want to bother with the time it would take, I've heard of them using bottles or buckets, at least for #1. One operator I heard of even got creative, employing a funnel attached to a very long hose, which emptied into a container down on the ground.

And this is most assuredly NOT reccomended for numerous reasons, both sanitation-wise, and to avoid a serious beatdown from one's co-workers, but my crane instructor told me about an idiot operator who just whizzed out his cab window whenever. Look out below!
Usually men can find ways around most of the bathroom dilemma, for obvious reasons. I'm still not sure what women do, as there are still so few of them.

KevinFromTexas
Oct 24, 2007, 4:34 AM
For anyone wondering how cranes are raised, that red structure around the shaft of the crane is the jack. If you look closely you can see one of the hydraulic pistons that raises it. That structure can move up and down the shaft. When they want to raise the crane, this jack crawls up the shaft to the top of the crane. It lifts up the top of the crane, including the boom (part that swings around). The jack also includes a tray that slides out. New sections of shaft are hoisted onto the tray by using the crane's hook. The new section is bolted into place and the jack raises up another level. They keep doing that until they get the height they need.
http://i177.photobucket.com/albums/w208/houtosme/HouConstruction/Mosaic2102107B.jpg
Photo credit goes to Wattleigh

Amanita
Oct 24, 2007, 10:32 PM
http://www.sitbonzo.com/crane/
check this out, it's truly horrifying. It's what happens when a climbing operation like this goes horribly wrong. Apparently they forgot to bolt the upperworks of the crane in place, and when they trolleyed that tower segment in, its balance was upset and over it all went.
Truly awful to look at.