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Capacity Spectrum Method of ATC 40 using ETABS - Printable Version

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Capacity Spectrum Method of ATC 40 using ETABS - paladin - 09-24-2010

Dear members of Civilea
I need help.
I did CSM procedure manually of course with help of ETABS & excel
What 'target displacement' that I should enter at the pushover case for CSM procedure ?
Should I calculate first "the target displacement" as in FEMA 273/356 & enter that 'target displ. of FEMA 273/356' to the pushover case ?
Thanks
Paladin


RE: Capacity Spectrum Method of ATC 40 using ETABS - iceman84 - 09-24-2010

Yes, you should calculate the target displacement first and enter with it in the pushover case. All the checks should be done at the target displacement.


RE: Capacity Spectrum Method of ATC 40 using ETABS - paladin - 09-26-2010

Dear iceman84
When 'performance point reached' in left-hand-side of etabs's window, appear 'pushover curve' and it's performance point & below this curve usually appear ( V,D) and it's value.
The questions :
1) What V & D are these ?
2a) This V must be compared to 'design base shear' (in conventional seismic design phase ) ? And this V must be smaller or bigger if compared to the design base shear ?
2b) This D must be compared to which drift or displacement limitation or others ?
Thanks for your time & your help
Regards
Paladin



RE: Capacity Spectrum Method of ATC 40 using ETABS - iceman84 - 09-26-2010

The performance point represents the maximum structural displacement expected for the demand earthquake ground motion. So you are interested in the value of the displacement, which you have to compare with the limit values (ATC 40 gives some limit values for the displacement).
Hope this will help you!