How are "Sustained + Earthquake + Seismic Displacements" combined in an AutoPIPE model?
This can be done by creating a new user combination with the Sustained case (SUS), Earthquake case (E1…E4) and SAM case (S1). It is important to understand the Seismic Anchor Movement load case (SAM). This is a pseudo dynamic load case which should be combined with a dynamic earthquake load case (Response Spectrum).
However, in this discussion earthquake load was applied as a static load, so instead of SAM, should be using either the Point/Member Static Earthquake Scale Factor option or applying these Imposed Displacements as a User Case or combined with the E1, E2, E3, E4 load cases.
IMPORTANT: In this example, a nonlinear analysis is being analyzed but many of the load combinations are inconsistent with the initial state for the occasional load, which is set to GR in this analysis set (shown below). Please review the information available to understand nonlinear analysis and load sequencing so that load combinations are combined correctly and the correct results are being used.
In this situation, 3 analysis sets was created… Analysis set 1 was shown to have the initial state for the occasional loads set to OP1, Analysis set 2 with the initial state for the occasional loads set to OP2 and Analysis set 3 with the initial state for the occasional loads set to OP3. If this was done, then these combinations will automatically be combined correctly.
Read through entire wiki - https://communities.bentley.com/products/pipe_stress_analysis/w/pipe_stress_analysis__wiki/8403/06-non-linear-load-sequencing-explained
Read through entire section - Within AutoPIPE, go to Help > Contents > Contents Tab > Reference Information > Analysis Considerations > Static Analysis > Nonlinear Analysis
Question: How should the "Seismic Displacement" of structures be entered into the model and how should the cases be combined?
Answer: This information will be outline in your project scope and the piping code you are using.