Get the response spectrum signal as a time domain signal

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moizhyd
Posts: 9
Joined: 22 Jun 2018, 15:42

Get the response spectrum signal as a time domain signal

Post by moizhyd » 27 Sep 2018, 09:08

Hello,

I am wondering if its possible to get the response spectrum signal as a time domain signal with Seismo Match.
After scaling the signal I would like to get the time domain output of applying this signal to multiple 1 DoF oscillators
becausw I am interested to use the response signal rather than the input signal.

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seismosoft
Posts: 594
Joined: 06 Jul 2007, 04:55

Re: Get the response spectrum signal as a time domain signal

Post by seismosoft » 27 Sep 2018, 17:48

No, it is not possible to do this directly in SeismoMatch. You should use SeismoSignal to get the response signal.
Seismosoft Support

huffte
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Location: Cookeville, Tennessee, USA
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Re: Get the response spectrum signal as a time domain signal

Post by huffte » 27 Sep 2018, 17:51

Hi moizhyd. Can you clarify your request? As a response spectrum is the response to an input signal at many different SDOF periods, I cannot quite tell what you are wanting to do. Perhaps you are wanting to take matched accelerograms (input signals) and apply them to nonlinear SDOF oscillators of varying period? If so, you could save the matched accelerograms and load them into SeismoSignal, which will generate not only elastic response spectra, but inelastic, constant ductility spectra as well. SeismoSignal will also provide inelastic time history of response for a specified initial period.
Tim Huff

moizhyd
Posts: 9
Joined: 22 Jun 2018, 15:42

Re: Get the response spectrum signal as a time domain signal

Post by moizhyd » 28 Sep 2018, 10:43

Hi Tim,

What I am trying to do is to arrive at a signal that is felt by a system which is inside a building.
So I start with a ground acceleration and essentially I want to scale this to account for the dynamics of the building.
I make a custom response spectrum that mimics the characteristics of the building for scaling the ground acceleration
signal and then do the scaling with seismo match.

After the scaling I however need the ouput signal or signals rather than the input because my goal as I mentioned
is to apply the scaled signal on a system that resides inside the building.

Please let me know if you have any suggestions on this apporach.

huffte
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Location: Cookeville, Tennessee, USA
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Re: Get the response spectrum signal as a time domain signal

Post by huffte » 28 Sep 2018, 14:37

Ah, I see moizhyd. You are needing to generate in-structure spectra, also known as floor spectra. There are approximate ways to take a building design spectrum and develop in-structure spectra. A google search on 'floor spectra' will get you some good information on that. The most theoretically correct method to do this, however, is to develop a structural model of the building (Seismostruct could be used) and apply accelerograms matched to the building target spectrum using SeismoMatch, for example. Suppose you wanted to look at equipment on the third floor. You would then take the appropriate 3rd floor node response history from Seismostruct to each of the accelerograms and generate spectra (Seismospect) using those records. So it is time consuming and relies on appropriately selected and matched records for input. The direct spectra-to-spectra method might be worth looking into. But the rigorous analysis is do-able. Best of luck.
Tim Huff

moizhyd
Posts: 9
Joined: 22 Jun 2018, 15:42

Re: Get the response spectrum signal as a time domain signal

Post by moizhyd » 18 Nov 2018, 18:32

Hi Tim
Would you have an end to end example of this that I could try out using the suite of the Seismosoft softwares ?
This would help me and my management understand better regarding investing in them. One of the issues
however is we do not have exact details of the building design. We can use generic models or worst case
scenarios as far modeling the building goes.Further could you explain what you mean by 'accelerograms matched to the building target spectrum'and 'spectra to spectra method'.FYI, we have already purchased a license of Seismomatch and finding it quite useful.Thank you.

huffte
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Location: Cookeville, Tennessee, USA
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Re: Get the response spectrum signal as a time domain signal

Post by huffte » 18 Nov 2018, 21:08

Ho moizhyd. If you email me through SeismoSoft and give me an email address, I will send two images I put together which outline a 9-step process. Hopefully, these will help in understanding the necessary procedure. I cannot attach images to forum messages, or I would put them here.
Tim Huff

moizhyd
Posts: 9
Joined: 22 Jun 2018, 15:42

Re: Get the response spectrum signal as a time domain signal

Post by moizhyd » 19 Nov 2018, 21:07

Hi Tim,

My email is moizhyd@gmail.com.
Thank you for the explanation.

moizhyd
Posts: 9
Joined: 22 Jun 2018, 15:42

Re: Get the response spectrum signal as a time domain signal

Post by moizhyd » 22 Nov 2018, 08:51

Hi Tim,

Thanks again for sharing the steps was very useful.
Did you receive my last email (reply to your mail about the steps) ?
Looking forward to hear from you.

SukanyaR
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Joined: 02 Apr 2019, 11:37
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Re: Get the response spectrum signal as a time domain signal

Post by SukanyaR » 02 Apr 2019, 11:41

The steps surely were to the point and pretty understandable.

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