API-650 Appendix E and Canadian (NBCC) Seismic Spectral Response Parameters

[MechWelder]

I have a question in regards to using the seismic spectral response parameters listed in the Canadian National Building Code(NBCC 2010) with API-650 Appendix E - Seismic Design of Storage Tanks.

I am confused by the differences in notation between the two standards and would appreciate confirmation from some more knowledgable/experienced members that I am in fact comparing apples to apples regarding the seismic parameters used in the two standards. Listed below are the two sets of parameters in which the notation differs between API-650 and NBCC:

Here are the spectral response parameters which are listed in the Canadian National Building Code (NBCC):

·PGA - (Peak Ground Acceleration – Based on 2% probability of exceedance in 50 years)

·Sa(0.2) - (5% damped spectral response acceleration, for the reference ground conditions, for a period of 0.2 seconds – Based on a 2% probability of exceedance in 50 years)

·Sa(1.0) - (5% damped spectral response acceleration, for the reference ground conditions, for a period of 1.0 seconds – Based on a 2% probability of exceedance in 50 years)

Here are the design parameters which are listed in API-650 Appendix E:

·S0 - (Mapped, maximum considered earthquake, 5% damped spectral response acceleration parameter at a period of zero seconds)

·Ss - (Mapped, maximum considered earthquake, 5% damped spectral response acceleration parameter at short periods (0.2 seconds))

·S1 - (Mapped, maximum considered earthquake, 5% damped spectral response acceleration parameter at a period of 1.0 second)

Please confirm that the following parameters are equivalent and can be used directly from the NBCC with the equations listed in API-650 Appendix E:

·PGA = S0
·Sa(0.2) = Ss
·Sa(1.0) = S1

Thanks for the help! I really appreciate it!

MechWelder.

 

[Ganotec]

Yes, these are correct equivalence.

Ganotec