| Applies To | |||
| Product(s): | AutoPIPE, | ||
| Version(s): | ALL | ||
| Area: | Analysis | ||
| Original Author: | Bentley Technical Support Group |
Problem:
The support at this location (ex. AB03), is a V-stop support, with the following settings:
Why when enabling the Non-linear analysis setting Ignore Friction E does the support have horizontal loadings, Zaxis: 254, Xaxis: 98?
Solution:
AutoPIPE is correctly calculating the loads on the support.
Again, do not concern yourself with the individual load cases (ex. Gr, P1, E1), only consider operating conditions (ex. GRT1P1E1) in your analysis review. One should only consider individual cases when trying to understand how they contribute to an operating condition results.
In this example, the individual loads case are added correctly to calculate the operating condition:
Again, why are there horizontal seismic loads on the support; 254 and -98?
For each static analysis set where "Ignore Friction E?" feature was enabled / turned on, all friction loads that occurred before each analyzed seismic load case will be released. To accomplish this, AutoPIPE will calculate the total friction force for all individual load cases as defined by the analysis load sequence (see Analysis Summary) to the specific seismic event. Then the software will apply an equal and opposite force value to essentially release the load on the support when calculating the operating condition.
Example:
- Load sequence = Gr -> T1 -> P1 -> E1
- Sum all individual load case forces acting on the support: (note, for V-stop there would be no vertical friction only friction on the horizontal plane).
- Apply equal and opposite total value for respective occasional seismic load (ex. E1); 254, -98 respectively.
- Refer to above SUPPORT report, exact same values were reported.
- When calculating the Operating condition, friction loads from Gravity, Temperature #1, and Pressure #1 are ignored / released.