mached acceleration

02-Analytical capabilities
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danielteruna
Posts: 10
Joined: 28 Jan 2013, 21:29

mached acceleration

Post by danielteruna »

Hi!
I want to know how to get match mean spectrum acceleration. As we know, when several acceleration were selected and matching to response spectrum target and we get macthed acceleration. sometimes these accleration using different scale factor.S0, how to get matched mean acceleration by the use selected acceleration with different scale factor.

Regards
Daniel
huffte
Posts: 978
Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA
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Re: mached acceleration

Post by huffte »

Hi danielteruna.

With SeismoMatch,"matching" to the target response spectrum is accompliched using wavelets added to the original time history of acceleration, not specifically through scaling of the original accelerogram.

Of course, you specify a scale factor when you read in the original accelerogram, and much judjement is required in determining this scale factor. To minimize the potential alteration of the original accelerogram, the scale factor should minimize, in some respect, the difference between the target and the scaled accelerogram spectra.

Please note that you must be aware of the nature of your target response spectrum. For example, if the target response spectrum is a geometric mean spectrum, then you might not want to match both horizontal components of a given record to the same target.

Once you have performed the matching in SeismoMatch, the Mean Matched spectrum is available in it's own tab. But, once again, these are spectra of records matched using wavelets, not straight amplitude scaling.

Best of luck.
Tim Huff
danielteruna
Posts: 10
Joined: 28 Jan 2013, 21:29

Re: mached acceleration

Post by danielteruna »

Hi! Huffte
Thank you for your response but I am not really understand. For example, there are 4 records original acceleration. I will matched these acceleration to target spectra one by one. Sometimes they can matched with different scale factor.Let's say 3 of them using scale factor 1.5 and the last one using 2. When I matched them simultenously, I can obtain mean acceleration.my question is what scale factor should be used? 1.5 or 2. If I choose 1.5 , the last acceleration maybe not matched, because of suitable scale factor for it is 2. would you please guide me about this problem

Regards
Daniel
huffte
Posts: 978
Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA
Contact:

Re: mached acceleration

Post by huffte »

Daniel, you may and should use a different scale factor for each of your 4 records. For example, you might wish to scale each record when it is read in to SeismoMatch so that:

(a) it's spectral acceleration at a certain period is exactly equal to the target spectral acceleration at that period or

(b) the means scaled error between the scaled accelerogram's response spectrum and the target is minimized over a range of periods

(c) some other means of scaling the accelerogram to improve the initial match to the target.

In this case, you would set both the scale factor in the settings button to 1.0 and the scale factor on the target spectrum to 1.0, with the appropriate scale factor applied by you up front when the record in read into SeismoMatch with the "Open Single" or "Open Multiple" button.

SeismoMatch then takes each accelerogram one by one an matches to the target over the range you specify by adding wavelets to the scaled records, one by one, as I say. So there is no reason not to use a different scale factor for each record.
Tim Huff
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