columns with corbel/ hammerhead column/ column with enlarge top

[sazvon]

hi.

i have to ask about this kind of columns..

my problems is...i am designing high rise building and i need to use transfer beam at the 10th floor. the transfer beam need to receive loads from 25 storeys above..hence, the size of the beam become so big. i need to make the width of the beam wider since i have the restriction to deepen the beam (floor to floor clearance); making the beam size: (2200x1500). however the column allowed is only 600x1500. i couldnt make the column size to be 2200x2200 because it will cause disturbance to floor area( staircase, ramp, parking lots).

therefore i was thinking to enlarge only the top part of the column..

so i want to know if i could design the column as column with corbels or hammerhead column just like we use to design for highway flyover and bridge.
or
does anyone here know any better idea?

i really appreciate every comments and help from all of you.

~saz(junior engineer_1 year experience)

 

[hokie66]

I answered in the other forum. Probably should have visited this one first, as it is the more appropriate. In the future, please observe the site rules against double posting.

 

[sazvon]

hokie66answer:
Do you need the extra depth for punching shear in your beam? If not, you may not need to provide a column capital or drop panel. You should consider the ability of the beam to bring the load to the column transverse to the beam axis, and you could possibly check that by a strut and tie analysis.

With 25 storeys being supported on the transfer beam, I would assume the beam is to be post-tensioned, with staged prestressing.

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on top of the transfer beam is load bearing wall with openings..


do you mean that the column can be not the same size of the beam..

or you suggest to strengthen the beam using to be post-tensioned, with staged prestressing..in that way the beam size can be reduce?

p/s: i've deleted my post in the other forum

 

[hokie66]

Not sure of the meaning of your question, but columns are often not as large as the beams they support.

Staged prestressing is used to account for deflections during construction. Post-tensioning does often reduce the required size of beams, but not always.

 

[KootK]

If I understand the situation correctly, I don't see the hammerhead helping really. If your problem was bearing stress at the top of the column, you're likely to still have the same problem at the bottom of the hammerhead. And the hammerhead likely only improves column stiffness about the column axis that is already very stiff (1500 wide). If you describe what isn't working with your column, we'll be in a better position to suggest alternate solutions. A sketch of the situation would also be helpful.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.