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[ranna]

Dear sefians
sometimes it is necessary to provide floating columns for the reasons
like greater passage width in ground floor, additional supporting
columns in other floors, bracing connections, providing walkways etc.,.
This is more common in high raised / heavy steel structures than rcc
framed structure.
r.anna

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[anandrshah9]

We agree that as a structural engineer one should always avoid floating
columns & slab beams.
But, sometimes it�s not in our hand to restrict floating columns or slab
beams because of pressure from client or architect.
What are the maximum precautions we can take in design/detailing of slab
beams?

Thanks & Regards,
Anand Shah

[p_kadam]

Dear all (Mr Anand Shah, Mr R Anna & like),

This topic often comes up & gets dumped as a foolish proposal. Those who encounter the unavoidanle situation are probably in minority & hence helpless. Will theSEFI fraternity rise to the occasion this time?

regards,

P Kadam

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[prof.arc]

It will be always an absurd idea to think that a system is a column if it
does not reach the ground and transfer the load to foundation directly.
thereis no such thing as a floating COLUMN. it is a misnomer and is only an
architechtural fancy.
ARC
On Mon Dec 5 11:31:46 2005, p_kadam[AT]vsn... wrote:

[rsm]

Dear All:

Floating column, stub columns etc. etc. are still columns as they carry
significant axial forces. Let us discuss the issues there and how these can
be designed rather than pushing this important issue under the carpet!

This is not Architectural Fancy but a Structural Reality. There are scores
of such buildings. So let us discuss these here.

Regards

Hemant Kumar

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[rtripathi]

Dear All,

We should design floating column only for gravity load(i.e. only vertical load) no horizontal load. And should not consider this as part of Moment Resisting frame.
并提供好详细的列beam from where it floats.

Regards,
Ramkrishna U Tripathi

-----Original Message-----
Message From rsm[AT]tou... [mailto:rsm[AT]tou...]
Sent: Tuesday, December 06, 2005 3:30 PM
To: Tripathi Ramkrishna (Mumbai - Civil)
Subject: floating coluns

Dear All:

Floating column, stub columns etc. etc. are still columns as they carry
significant axial forces. Let us discuss the issues there and how these can
be designed rather than pushing this important issue under the carpet!

This is not Architectural Fancy but a Structural Reality. There are scores
of such buildings. So let us discuss these here.

Regards

Hemant Kumar

Posted via Email

[rtripathi]

Dear Ms. Sangeeta,

You are correct, if we can avoid the floating column it is very good for structures. I am also agreeing in line with you that most of time such modifications are added when we have finish foundation design for structures. But still I have feeling that by rearranging your flow of load from super structures to foundation we can produce good structure.

Regarding you question for detailing, I am talking about shear & torsion detailing. By provide sufficient depth, width & extra reinforcement, we can Minimize torsion effect ( I am not saying that, there is no torsion). Try to tie the support beam and floating column from both directions, this is will reduce the slenderness effect.
And about horizontal force....I think you must agree with me, that it is up to us "How the structures behave in lateral load case" (It is Engineer who decides the behavior of structures). And I can ignore/ avoid floating column be part of moment resisting frame.

If you have still any queries please feel free to write.

Thank you,

Regards,
Ramkrishna U Tripathi.

-----Original Message-----
Message From sdec[AT]bol... [mailto:sdec[AT]bol...]
Sent: Tuesday, December 06, 2005 6:01 PM
To: Tripathi Ramkrishna (Mumbai - Civil)
Subject: floating coluns

Dear Mr Tirupathi,
If u dont mind, can u pl elaborate what exactly is ur concept of a good
detailing?? and as to how u will prevent it frm being a part of moment
resistant frame after such a good detailing has been done??How can u detail
it to avoid heavy torsion being created in such a case? It is allright if u
defend this concept to reconcile some architect friends or some non
technical clients (who claim to know better engineers who can deliver
solutions to all the problems)...but the fact is that such columns are
normally added at a much later stage in the superstructure after the
foundations and columns have been cast...mostly the machine room and mumty/
Overhead tank supporting structure details are never worked out by the
architects till this stage...dont you agree that it is always a compromise
and not a sound str solution to agree to provide floating columns??I've also
checked a society where,, the architect added penthouses on top floors and
altered the str system quite substantially and added floating
columns..almost after half the bldg had already come up....in such a case it
was a designers nightmare to transfer even the gravity loads
correctly..leave alone the horizontal forces.
regards
sangeeta wij

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