
	Applies To

	Product(s):	AutoPIPE
	Version(s):	V8i
	Area:	Combinations
	Original Author:	Bentley Technical Support Group
	Date Logged & Current Version	April. 2015 09.06.01.11

Problem:

We have used seismic E3 (+X), E4 (+Y), E5 (+Z) and W1 (Wind +X N -S), & W2 (+Z, E-W) direction load cases. Calculations were performed an a Linear analysis, On the non-Code Comb. We are also using combination option - "Add negative Occasional cases". We thought this will perform combination like GR+E1 or GR+W1 and GR-E1 or GR-W1. But looking at Restraint reactions it does not show correct results. It gives “-4” for both direct ions in Z direction. Are we doing something wrong?

Solution:

As mentioned in the online help for "Add Negative Occasional Cases"

If this option is selected, the program will generate default Non-Code combinations for negative occasional load cases in addition to the default Non-Code combinations for positive occasional load cases of seismic and wind only, i.e. GRTP1+W1, GRTP1-W1, GRTP1+E1, GRTP1-E1, etc.

Additional comments for this particular issue, the model was constructed with small bore piping (i.e. OD = 2.375") over 4 different segments (Seg A-D). In this model, Wind was found to be only applied to segment D (i.e. a very small pipe segment). Model Input Listing report, Load Summary Data Listing sub-report,

There is not enough surface area for the wind to really affect the model. Confirm Wind should be applied to the entire model or just this small segment. Make the necessary adjustment to the Wind load case.

"Add Negative Occasional Cases" Combination Options on the Load Combinations dialog in AutoPIPE

Problem:

Solution:

See Also