Question:
For a specific combination expression, I would like to consider a load case with a combination coefficient that deviates from the standard. How can I proceed?
Answer:
First, you should consider whether it would not be easier for the different combination expression to create the load combinations manually, in addition to the automatically generated combinations. If there are only a few load combinations, you can create them quickly. However, if the effort is considerable due to many load cases, you can proceed as follows:
Example
For "earthquake" combination expressions according to EN 1990, snow (≤ 1,000 m) should be considered using ψ-2 = 0.5 instead of ψ-2 = 0.0. For the "Permanent/Transient" design situation, however, ψ-2 should be considered as 0.0 according to the standard.
In order to consider different values for both combination expressions, it is necessary to copy the snow load case and to change the action category of the copied load case to "Other" (see Image 01).
By default, the combination factor ψ-2 is preset with 0.5 for this action category (see Image 02).
If you need a different value, you can select a different, suitable action combination for the copied load case. If no action category meets the desired value, you can create a user-defined standard. You can find the description of how to do it by clicking the link below this FAQ.
In order to avoid the superposition of Load Case 3 and Load Case 4 shown in Image 01, the respective load case must be excluded in the combination expressions. To do this, use the "Reduce number of load cases ..." function (see Image 03).
Then, you can assign the load cases to be combined with the respective combination expressions (see Image 04 and Image 05).
Now, you obtain the desired load combinations (see Image 06).
