Parameters for manual pushover procedure

03-Analytical/modelling capabilities
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warcorsario
Posts: 18
Joined: 26 Jul 2019, 01:16

Parameters for manual pushover procedure

Post by warcorsario »

I interesed in verify the performance point using Capacity Spectrum Method (ATC-40), in this case it is necessary to do a manual procedure using a spreadsheet (excel), for which it is necessary to convert the pushover curve into capacity spectrum and other hand obtain the demand spectrum.

To obtain Capacity curve is necessary used the formula Sa=V/(W*alpha1) , V is base shear, W is weight and alpha1 is modal mass coeficient corresponding to first mode. Sd=delta/PF1, Delta is story displacement and PF1 is modal participating factor refered to first mode.

how could obtain W, alpha1 and PF1 parameters in seismostruct? or is possible obtain first mode amplitude at level i (Phi1i) and assigned mass to level i (wi/g)?, because is necesary to manual procedure of performance point verify.
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seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: Parameters for manual pushover procedure

Post by seismosoft »

After running pushover you can get in the post-processor the following results:
1) the base shear at any step can be extracted from the Global Response Parameters>Hysteretic Curves
2) the weight of the structure can be extracted from the Global Response Parameters>Forces and Moments at Supports
3) the Modal Participation Factors can be extracted from the Eigenvalue Results page (this can only be seen, if you have activated the Target Displacement calculation from the pre-processor, Target Displacement tab).

Note that the target displacement according to EC8 (one variant of the CSM) and ASCE 41 (equation method) can be automatically calculated. Furthermore, the program automatically carries out the bilinearisation of the capacity curve (Target Displacement tab of the post-processor)

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warcorsario
Posts: 18
Joined: 26 Jul 2019, 01:16

Re: Parameters for manual pushover procedure

Post by warcorsario »

Thanks for your answer, how could obtain modal mass coeficient corresponding to first mode (alpha1)? i need its parameters because is necessary make manual procedure with Capacity Spectrum Method (ATC-40), I am using spectra demand from seismic code of my country (Perú).
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z.gronti
Posts: 824
Joined: 16 Oct 2013, 08:14

Re: Parameters for manual pushover procedure

Post by z.gronti »

Dear warcorsario,

The Modal Periods and Frequencies module, found in the Post Processor> Eigenvalue Results, provides a summary of the main eigenvalue results, i.e. the natural period/frequency of vibration of each mode, the modal participation factors, the effective modal masses and the effective modal mass percentage.
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warcorsario
Posts: 18
Joined: 26 Jul 2019, 01:16

Re: Parameters for manual pushover procedure

Post by warcorsario »

Thanks for yours answers, how could obtain modal first mode amplitude at level i (Phi1i)? because is necessary to convert capacity curve in capacity spectrum.
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