Differently Acting Load Cases for Automatically Created Combinations
For the automatic load case combination in RFEM and RSTAB, you have to enter the possible interaction of load cases. In addition to the simultaneous or alternative occurrence of all load cases of an action, an option for different combination conditions is possible.
Differently Acting Load Cases
For a simultaneous action of load cases, cases may occur individually or together in a combination; in the case of an alternative action, only one load case of this action is possible. If this general definition is not sufficient for the load cases of an action, the different action can be defined by means of groups. An additional column is displayed that allows you to assign load cases to groups.
Within a group, the load cases are combined as alternatives to each other. Thus, only one load case from a group is considered when creating a combination. For the groups among themselves, the simultaneous combination rules apply, so one load case from each group could be contained in a combination.
If load cases are not assigned to a group ("-"), the simultaneous action applies to these load cases both among themselves and in relation to the groups.
Further relations of load cases can also be defined over all actions in the combination expressions.
Dipl.-Ing. Oliver Müller
Product Engineering & Customer Support
Mr. Müller is responsible for the development of the add-on modules for steel structures and provides technical support for our customers.
- Automatic Generation of Load Combinations in RFEM
- Automatic Generation of Load Combinations in RSTAB
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In addition to the basic combination rules of EN 1990, there are other combination conditions for actions on road bridges specified in EN 1991‑2 that must be taken into account.
Depending on stiffness, mass, and damping, structures react differently to wind action.
- Although I have selected "simultaneously" for several load cases within one action category, there are also load combinations generated that do not act simultaneously.
- What does the meaning of the action acting "Differently" when I define the action categories?
- I design timber components. The deformations of load combinations deviate from the manual calculation exactly by the factor of the material partial safety factor. Why?
- I have created automatic load combinations according to EN 1990 + 1995 (CEN). Although Ψ2,1 = 0, there are the factors greater than zero applied for wind and snow. Is this a program error?
- I use automatic combinations, but some load cases are not used in the generated combinations. How can I change it?
- I have used the RF‑/DYNAM Pro add-on module to generate the governing result combinations of seismic loads. What is the next procedure to perform the design of the individual structural components?
- Why is it not possible to select the individually or simultaneously acting load cases in the "Combination Expressions" tab?
- There are no load case numbers (LC1, LC2, LC3, ...) but action categories (D, W, S, Imp) displayed for load combinations. Where can I set this?
- How can I generate load combinations automatically in an existing file retroactively?
- Why do some external pressure coefficients have a value of 0 when generating wind loads?
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