Period step on response spectra

[Alban Kita offline]

Dear Seismosoft Team

It has been told to me in the emails that there isn’t any limitation in the minimum period step for spectra in the commercial version or in general the advantages of the commercial version are that it does not have any of the limitations of the academic one.

I am using an acceleration time history with step dt=0.005 sec . For the reponse spectra i want to use a period step equal to 0.005 sec but the software limits me to 0.01, and further when i save it in a text file i see that the period step is 0.02 .
Can you tell me how can i solve this issue?

Best regards
Alban Kita

[huffte offline]

Hi Alban Kita. You might find it useful to display the response spectrum values by selecting "values" rather than the default "graph". This will present you with a table matching your specified period step which may be selected, copied, and pasted into Excel or most any other application (right click -> select all, right click -> copy). I actually find this to be more convenient than saving to a text file.

As for your desired period step of 0.005 seconds, I would say that while you may have valid reasons for such a refined increment, it does seem much smaller than typically encountered, at least by me. I have found a period step of 0.02 seconds to be adequate, but as I say, you may have your reasons and want to pursue that issue further.

Best of luck with your work.

[Alban Kita offline]

Dear Tim Huff,

First, i thank you very much for your comment.
I prefer the save spectrum option because it saves all (output in 6 columns: period, acc, vel, disp, ps-acc, ps-vel) in one text file, thus, being faster. Anyway, for me the problem is the period step. For now i am working with an acceleration time history with dt=0.005 sec, that's why i want te have a response spectra with period step of 0.005 seconds.
The software allows me until 0.01 sec: Can you help me please how to put this period step of 0.005 sec?

I thank you in advance
Alban Kita

[huffte offline]

You can have it all in one excel file as well via the procedure i previously outlined. Or, if you prefer, there is nothing to prevent you from copying and pasting into notepad and saving as a text file. Additionally, just because the loading history time step is 0.005 seconds has nothing to do with the period step in the response spectrum. Using a smaller period step does not increase the solution accuracy at the periods considered. It only increases the number of periods considered. There is no need to make the period step equal to the time step.

[seismosoft offline]

Hello Alban Kita,
As we explained via email, there was a misunderstanding between our Sales and our Development sections. Indeed, the limit is 0.01 sec, however as we promised we will create a custom release for you that is able to handle periods smaller than 0.01 sec.
Apologies for the inconvenience that we caused.

Regards,
Seismosoft Support

[Alban Kita offline]

Dear Seismosoft Team,

Misunderstanding between people are normal. It is ok. I thank you very much for your availability.

Regards,
Alban Kita

[seismosoft offline]

Hello,
We have just sent you an email with the custom release that we promised.
If you have any further queries, do let us know.
Renewed apologies for the misunderstanding and the inconvenience.
Seismosoft Support