STORY STIFFNESS

Offline pnnaik over 9 years ago

I would like to know how staad calculate story stiffness?

I am using FLOOR DIAPHRAGM and PRINT STORY STIFFNESS to get story stiffness from staad.

Now suppose structure with 5 floor and same height. All column and beam are of same size. When I check story stiffness result why they differ floor to floor when all floor are similar?

Kindly reply.

Regards,

PNSTORY STIFFNESS.std

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Offline pnnaik Wed, Feb 25 2015 6:13 AM in reply to DSANJU +1

Thank you for your kind reply. In attached file structure has 5 floor. Each floor have 3m height. All column and beam have same property. I suppose to get same story stiffness from staad. But result…

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Offline DSANJU Wed, Feb 25 2015 6:03 AM
Please find the attached document which explains the process of calculation of storey stiffness in the presence of rigid floor diaphragm.
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Offline pnnaik Wed, Feb 25 2015 6:13 AM in reply to DSANJU

Thank you for your kind reply.
In attached file structure has 5 floor. Each floor have 3m height. All column and beam have same property.
I suppose to get same story stiffness from staad. But result are giving varying stiffness floor wise. Why is it so?
Kindly go through attached file.
Regards,
PN
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Offline pnnaik Wed, Feb 25 2015 6:13 AM in reply to DSANJU

Thank you for your kind reply.
In attached file structure has 5 floor. Each floor have 3m height. All column and beam have same property.
I suppose to get same story stiffness from staad. But result are giving varying stiffness floor wise. Why is it so?
Kindly go through attached file.
Regards,
PN
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Offline pnnaik Wed, Feb 25 2015 6:19 AM in reply to pnnaik

I mean to say if we use equation 12EI / L3. It should result in same story stiffness for all floors.
Regards,
PN
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Offline DSANJU Wed, Feb 25 2015 6:27 AM in reply to pnnaik
Please refer to the document that I have attached. Storey stiffness is calculated from the relative displacements of the centre of mass of each floor. A sample calculation has also been explained.
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Offline Dushyant Gambhava Fri, Feb 26 2021 12:12 PM in reply to pnnaik

Hello pnnik,
I am having the same question.
Did you figured out the solution.
Please do let me know,Im having the same problem.

Thank You.
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