| Applies To | |
| Product(s): | AutoPIPE |
| Version(s): | ALL; |
| Area: | Calculations |
| Date Logged & Current Version | March 2019 12.00.00.14 |
Problem:
Hand calculated ASME Section III, Div.1 Class 1 NB-3653.1 Equation 10 result considering only seismic inertia and earthquake anchor movements is exactly one half the value calculated by AutoPIPE. why?
Solution:
As shown in AutoPIPE help, code compliance calculations:
The Range of resultant moments from seismic anchor movement loading and seismic inertia loading should be defined as 2 x sqrt (Mix^2+Miy^2+Miz^2), found that hand calculations did not include this 2x multiplier. Thus the hand calculated value was 2x smaller than AutoPIPE reported value.
The factor of 2 shown in help documentation is due to description of 'Mi' in ASME-III-1-NB-3653.1 which states that for load combinations that include reversing dynamic loads only, the full range of the reversing dynamic loads are to be used (versus half-range or 'amplitude' when all loads (static and dynamic) are considered).