Pushover Analysis Error

04-Unexpected behaviour/errors
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sh.hosseinzadeh
Posts: 5
Joined: 30 May 2016, 21:35

Pushover Analysis Error

Post by sh.hosseinzadeh »

Hi there,
I have a building modeled with SeismoStruct 2016, while I am trying to perform pushover analysis it will end up getting me weird responses and/or not converging at all. I have checked the file several times to make sure there is no material error. but I can not fix it.
Can anyone diagnose this issue? I also enclose the dropbox link such that you can download the file.

https://www.dropbox.com/s/06r1j51orkowg ... 7.spf?dl=0

Regards,
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seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: Pushover Analysis Error

Post by seismosoft »

But you have not connected the control node (and all the centres of the slabs in the different floors) with your structure. The rigid diaphragms is not enough. Better to use a rigid link.

Seismosoft Support
sh.hosseinzadeh
Posts: 5
Joined: 30 May 2016, 21:35

Re: Pushover Analysis Error

Post by sh.hosseinzadeh »

Thanks for your reply,
Can you elaborate a little bit? what I did is using a rigid diaphragm besides introducing a node at the center of mass of the structure and I connected all of them together using a rigid diaphragm constraint.
how can I use rigid link instead since it doesn't yeild the same results when I am doing eigenvalue analysis?

Regards,
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seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: Pushover Analysis Error

Post by seismosoft »

The Z+RX+RY DOFs of the control nodes are not connected in any way with the rest of the structure. This is what is mentioned in the warning message that you get, when you start the analysis (always pay attention to the warnings at the beginning!)

Regards,
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obaidullah khan
Posts: 21
Joined: 11 Sep 2023, 14:24

Re: Pushover Analysis Error

Post by obaidullah khan »

hello,
i did static pushover analysis and IDA of my structure got the results, but this time when i added 2 shear walls in building and run the PO analysis, the analysis is not running and giving the error "warning: could not re-orthogonalise all Lanczos vectors".why is it so, what could be the reason as i have connected the shear wall nodes to rigid diaphragms and control node of story through rigid link.
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z.gronti
Posts: 824
Joined: 16 Oct 2013, 08:14

Re: Pushover Analysis Error

Post by z.gronti »

Dear obaidullah khan »,

If you carry out a search in this Forum on "could not re-orthogonalise all Lanczos vectors" you will find posts with hints on this issue.
Zoi Gronti
Seismosoft Srl.
obaidullah khan
Posts: 21
Joined: 11 Sep 2023, 14:24

Re: Pushover Analysis Error

Post by obaidullah khan »

Dear Zoi Gronti,
Thanks for your response I carry out the research and I got some connectivity issue in my model, I solve that now my analysis run completely and all values got converge but the issue is software is not considering the shear walls which I have added. Program is giving the same base shear value as my other model was without retrofitted. I have connected the shear wall to rigid diaphragms and also connected to control node of each story through rigid link constrains
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z.gronti
Posts: 824
Joined: 16 Oct 2013, 08:14

Re: Pushover Analysis Error

Post by z.gronti »

Dear obaidullah khan,

Please check the connectivity of the added walls with your model and the walls' support conditions.
Zoi Gronti
Seismosoft Srl.
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