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In RAM Elements (and Ram Connection), every load combination is given a type that determines when the load combination is utilized. The figure below illustrates how several different types of combos could be used in a single file.
On the Analysis tab of the Process – Analyze model dialog box, the user indicates if second order analysis will be considered. This is required when using tension-only members or compression-only springs, but may be turned on for any model.
Whenever a second order analysis is performed, the program individually analyzes each selected load case on the Condition tab.
If second order analysis is NOT performed, then the program only analyzes the selected load cases. The results for all combinations are generated using the principal of superposition, so the user can no longer uncheck individual combos.
Furthermore, if the user opts not to analyze certain load cases, any combinations including those load cases will not have any results available.
The program uses "Service" or "Service-Steel" type load combinations for checking beam deflections. If a model has only "Design" or "Design-Steel" combinations and no service combinations, this feature will not be available. Add at least one service combo (e.g. 1.0 DL + 1.0 LL) to access this feature.
In the continuous beam module, if you have skip loading defined with any percentage it's important to generate combos using the Continuous Beam Combo Generator designed for skip loading (.cbg files). If you use the general RAM Elements Combo Generators (.rag files) you get something like this:
1 DL
2 DL+LL+SK1+SK2+SK3+SK4
i.e. with all the live load cases (LL,SK1, SK2…) together. The result is a combination which effectively doubles the live load.
It should be more like this:
2 DL+SK1
3 DL+SK2
4 DL+SK3
i.e. with each skip load case used independently, which is what you get using the .cbg combo generators.
Structural Product TechNotes And FAQs
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