UFC 3-310-04 Acceleration

[vmirat]

I'm designing a slab on grade pad for an outside HVAC chiller. This is a DoD project, so it requires the use of UFC 3-310-04, Chapter 4 for an MC-1 component. Equation 4-4 requires the use of a[sub]ip (component spectral acceleration). Would you use S[sub]DS from ASCE 7-05 for a[sub]ip?

 

[MRH1335]

If you use SDS with Ip=1.5 you should good since you would be at the flat part of the spectrum. But you also should check the magnification factor depending on the equipment-foundation frequency ratio (less than 0.7 and more than 1.3 is acceptable).

 

[shin25]

I believe, the short period acceleration, Sds that is included in UFC should match with that in ASCE 7. Therefore, you should be fine if you use Sds from ASCE. Component Importance factor (Ip) can also be taken from ASCE.