Information on "Tube Structure"
Information on "Tube Structure"
(OP)
Hello,
I am a new structural engineer. I am looking at a example of a eight story building 60' x 60'. I am trying to understand the way the structural system works.
The exterior walls are moment frames. The columns are spaced closer together than the interior columns. The beams on the inside are connected to the exterior columns with a pinned connection. I have found some information calling this a tube structure. This book says that the moment frame resists the lateral forces and some gravity forces. The interior columns are designed only to carry vertical forces. I do not understand why this is true. I would think that the effect would be felt also on the interior. Does it have to do something with the reaction between the metal deck and the floor system?
Thanks
I am a new structural engineer. I am looking at a example of a eight story building 60' x 60'. I am trying to understand the way the structural system works.
The exterior walls are moment frames. The columns are spaced closer together than the interior columns. The beams on the inside are connected to the exterior columns with a pinned connection. I have found some information calling this a tube structure. This book says that the moment frame resists the lateral forces and some gravity forces. The interior columns are designed only to carry vertical forces. I do not understand why this is true. I would think that the effect would be felt also on the interior. Does it have to do something with the reaction between the metal deck and the floor system?
Thanks






RE: Information on "Tube Structure"
What you describe sounds more like a sway framed building than a tubed structure, you may want to do a bit of reading in that direction.
As for what resists the lateral forces, it largely depends on how you design it. If the interior columns have pinned connections to the beams then they will take no significant part in the lateral load resisting system.
Here is a good website to look at:
http://
csd
RE: Information on "Tube Structure"
Also the structural system (tube structure) that you have described, are well effective during a progressive collapse.
RE: Information on "Tube Structure"
RE: Information on "Tube Structure"
DaveAtkins
RE: Information on "Tube Structure"
The World Trade Center Towers were examples of tube structures (one extrerior tube). The Sears Tower is a bundled tube (9 tubes acting together).
I hope this helps!
RE: Information on "Tube Structure"
And this is why (mainly) both the structures stood without collapsing for 1 1/2 to 2 hours after impact. This saved lot of lives. 'tube' Saved the structure from immediate progressive collapse.
RE: Information on "Tube Structure"
I assume you have an elevator shaft on this building, is there a reason why you are not using this to resist the lateral loads?
csd
RE: Information on "Tube Structure"
I absolutely agree! The redundacy of this system was remarkable in saving lives!
RE: Information on "Tube Structure"
Thanks for the replies, that link was great. There is a elevator shaft, but it is all the way in the front off the structure (right against the exterior wall). In the rear of the buillding it is all open.
I was thinking that using the elevator shaft to resist the lateral loads would cause some excentricity in the design/building. Is there a way that I could incorporate it?
Thank You
RE: Information on "Tube Structure"
If this is in a seismic zone then this may make picking a structural response value a bit tricky.
csd