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ASCE 7 Story Drift & STAAD

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Another question:

It does not appear that the program is taking into account IBC 2003 story drift criteria.  for one, when computing seismic forces, for the ibc referencing the ASCE 7, it details in ASCE 7 not to use the period cutoff values and shear cuttoff values.  i do believe that STAAD does not account for this.  is there a way to remove the cutoff period and shear for automatic ibc eq generation?

further, it would be nice if the story drift calcs could signify torsion irregularities, and compute drift according to ASCE 7 Exception. 


On 12/30/05, Support <support(--nospam--at)> wrote:
If you go to the General Property page, you will find a tab called Define along the right side. Click on that. You will find an option called General.

Specify the member dimensions for YD and ZD (specify YB and ZB also if it is a Tee shape). Then, since the code suggests you reduce the property values to account for cracking, specify the reduced values for AX (Area), IZ (moment of Inertia about Z), IY (moment of inertia about Y), etc. in their respective boxes. Assign this to the member.

The analysis will then be based on what you specified for AX, IY, IZ, etc. The design will be based on the YD and ZD you specified which happens to be the full section dimensions.

STAAD Support Group

---------- Original Message ----------------------------------
From: refugio rochin < fugeeo(--nospam--at)>
Date:  Thu, 29 Dec 2005 14:12:19 -0400

>How do people here use STAAD to deal with ACI 10.10 or 10.11 ?
>Usually in my analyses, what I would do is conduct a first order analysis
>using the reduced sections Moments of Inertia from 10.11. and use the pdelta
>to account for the moment amplification.
>Visual Analysis has a convenient reduction factor for the members input.
>have something similar?
>For the situation, I think I will have to create two models, one for
>deflections and one
>for member design.  The first will use a modified Inertia in the input for
>according to 10.11, the second will have the design dimensions.  Both
>will be second-order elastic analyses.

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