Maximum Displacement in SPA

[karabi]

Dear All,

My query is regarding the maximum displacement in the loading phases. I have used response control. Does the performance levels in SPA changes with the increase in the maximum displacement? I have observed that the point of performance criteria (PC) changes when comparatively higher value of maximum displacements is taken specially when the building is non ductile(Stirrups largely spaced). Say I obtain a PC at 0.03m when I take a maximum displacement of say 1.5x(0.004xheight) but this PC changes to say 0.05m when I take 2.5x(0.004xheight). Is this because the maximum displacement is too high and the structure is quite unstable at that such high displacement? So should I take the PCs for the SPA with reasonable maximum displacements?

Apart from this, I would like to know why isn't the LS level of performance criteria as per ASCE is not included? I could find only yield chord rotation and capacity chord rotations.
Thanking you in anticipation

with warm regards,
Karabi

[seismosoft]

I am not sure what you mean with SPA, but the maximum pushover displacement does play a role in the determination of the target displacement, when a full capacity curve is not achieved, i.e. when the pushover analysis does not provide a full capacity curve until the descending branch. Please refer to the parts of the codes that describe how the target displacement is calculated.
Regarding your question about the performance criteria of ASCE, the corresponding equations are indeed supported (refer to the Performance Criteria module).

Seismosoft Support

[karabi]

Thanks for the response. By SPA I mean Static Pushover Analysis. I checked the performance criteria module. For ASCE Equations, I could find the chord rotation yield and chord rotation capacity. So if I consider the yield one as Immediate Occupancy(IO) and capacity as Collapse Prevention(CP), which criteria should I choose for Life Safety(LS) ? For a number of models its difficult to put manual values of LS as available in the ASCE equations and tables. And I could not find any automatic values. I could find automatic calculation for yield and capacity only. Please suggest.

Thank you,
With warm regards,
Karabi

[z.gronti]

Dear Karabi,

I think that the Code-based checks is what you are looking for. You may check the chord rotation capacity in any of the four limit states of ASCE 41-17, i.e. Operational Level, Immediate Occupancy, Life Safety and Collapse prevention.

[karabi]

Dear Zoi Gronti,
Thanks a lot. I was searching for that only. However I didn't focus in that code check tab as it limited to only 20 members in academic version. Isn't? So I can check the Operational Levels for all the members if I purchase the seismostruct software?
Thanks and regards,
Karabi

[z.gronti]

Dear Karabi,

Yes, that's right. The only limitation of the academic version of SeismoStruct is that it supports code-based checks for up to twenty members.

[karabi]

Thank You