comparisons between different programs

02-Getting started with the modelling
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hashemian
Posts: 6
Joined: 28 Feb 2011, 14:56

comparisons between different programs

Post by hashemian »

Hi,
I modeled a 9 story 2-D bulding with both Siesmostruct and Sap2000.
The pushover curves are so different! The displacement of the pick Force is 1.4m in Sap and less than .1m in Siesmo. (the pick forces are nearly the same.)
Is that possible?
Can any one help me by checking my model?
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seismosoft
Posts: 1263
Joined: 06 Jul 2007, 04:55

Re: comparisons between different programs

Post by seismosoft »

Dear hashemian,

There may be tens of reasons for the differences you report, especially when such markedly distinct software packages are being used.

You should certainly check your model assumptions carefully (perhaps in collaboration with other users, if they so volunteer).

The one thing that we may note immediately is that a drift of 5% at point of peak resistance seems quite high and unlikely.

Seismosoft Support
hashemian
Posts: 6
Joined: 28 Feb 2011, 14:56

Re: comparisons between different programs

Post by hashemian »

Thank you so much.
benamer
Posts: 8
Joined: 04 Jul 2011, 17:40

Re: comparisons between different programs

Post by benamer »

Dear hashemian
There are many things that can cause this difference in displacements. Your input of material properties( strength, direction of cross section of members(x&y)). If you have different orientation of the members cross sections, you would get different answers.
Another thing is nonlinearity. If you run SAP2000 within the linear limit you are likely to get a large displacement.
Thers is no 2D represntation in Seismostruct. So you might be comparing a 3D to a 2D analyses, which causes the difference.
Best regards.
Mohamed Omar
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