range of matching

02-Analytical capabilities
beiraghii@yahoo.com
Posts: 12
Joined: 14 Feb 2014, 05:39

range of matching

Post by beiraghii@yahoo.com »

Hi
To perform Spectrum-matching:
1-what should be the range of matching? Is 0.2T1 to 1.5T1 as used for conventional scaling is enough? (T1 =1.4*code resulted T<numerical T) Could you, please, recommend me some references for this?

2-In some cases the matching is not matched very good (visually), specially at the short period of spectrum for tall building. what should we do in this case to match better? I have used several roughly scale factors for ground motion but the matching results is not satisfactory, I think.
huffte
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Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA
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Re: range of matching

Post by huffte »

ASCE 7, NIST GCR-11-917-15, are 2 references for the .2T-1.5T rule.

It all depends on your desired goal. It is possible to match over wider ranges if needed.

For an individual record, the match may not appear ideal visually. But with enough records matched, the mean of the suite of records can still be a very good match. In fact, in my experience, an individual record may not converge, yet when combined with other records and the mean calculated, a very tight match to the target is attainable.

And the closer the original accelerogram matches the overall shape of the target spectrum, the more success you will have with an individual record.

I have found SeismoMatch to be a valuable tool for this.

Best of luck, beiraghii@yahoo.com.
Tim Huff
Navid
Posts: 17
Joined: 18 Jun 2017, 02:09

Re: range of matching

Post by Navid »

Hi. The Max period in the the matching parameters tab under the settings section is set to 4. Is there any chance that the said parameter could be changed to a larger value?

Regards,
Navid
Navid
Posts: 17
Joined: 18 Jun 2017, 02:09

Re: range of matching

Post by Navid »

I just wonder why the minimum value associated with the matching period range otta be defined more than 0.05!

Thanks a billion!
Navid
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z.gronti
Posts: 824
Joined: 16 Oct 2013, 08:14

Re: range of matching

Post by z.gronti »

Dear Navid,

You may insert the values that serve your goal. According to the SeismoMatch Help System the Min and Max periods are "Lower and upper period bounds within which spectral matching is carried out.". In addition, note 4 of the same topic informs that "The spectrum matching period range (defined by the Min and Max period parameters) should, in principle, consider not only the fundamental vibration period of the structure that will be analysed through nonlinear dynamic analysis, but also the higher modes that might affect the structure's response as well as the effects of period elongation due to damage accumulation (and corresponding structure stiffness decrease). ".
Zoi Gronti
Seismosoft Srl.
Navid
Posts: 17
Joined: 18 Jun 2017, 02:09

Re: range of matching

Post by Navid »

Dear Zoi,

The irksome point is that SeismoMatch considers the value of 4 for the upper bound on the horizontal axis of the seed response spectrum from EC8 or other codes and standards. Into the bargain, the period of my target response spectrum of interest is from 0 to 5 sec: yet, SeismoMatch plots it towards 4 seconds. Do you happen to know how to excel the said value for the horizontal axis of the target response spectrum?

Thanks a million in advance!
Navid
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z.gronti
Posts: 824
Joined: 16 Oct 2013, 08:14

Re: range of matching

Post by z.gronti »

Dear Navid,

You should change the value of the Max. Period in the "Response Spectra" tab in the "Settings" module.
Zoi Gronti
Seismosoft Srl.
Navid
Posts: 17
Joined: 18 Jun 2017, 02:09

Re: range of matching

Post by Navid »

Thanks heaps, Zoi!
Navid
Posts: 17
Joined: 18 Jun 2017, 02:09

Re: range of matching

Post by Navid »

Could you please help me out with matching the yellow response spectrum to the red one as the seed response spectrum? It should be voiced that I have been playing with the Min and Max periods; yet, it went haywire!!!

Image
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z.gronti
Posts: 824
Joined: 16 Oct 2013, 08:14

Re: range of matching

Post by z.gronti »

Dear Navid,

Please check the assigned values for the min and max periods in the "Matching Parameters" module of the Settings.
I would suggest you to use the program default parameters or read the "Spectral Matching" topic of SeismoMatch Help System for a better understanding of the available Spectrum Matching Parameters.
Zoi Gronti
Seismosoft Srl.
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