Reducing Load Cases for Automatic Generation of Combinations

Tips & Tricks

In RFEM and RSTAB, you have the option to automatically generate load combinations. A large number of load cases and action categories can result in an even larger number of possible combinations. To handle this, we implemented an option to reduce these combinations. By selecting the according check box in the ‘General’ subtab of the ‘Combination Expressions’ tab, the ‘Reduce - Number of Load Cases’ subtab becomes available. There are five sections in this subtab.

Section 1 ‘Choice of Load Cases’

In this section, you specify the reduction method. If you select ‘Manually’, you can select the load cases yourself in groups in Section 2. If you select ‘Automatically’, you have two further choices: you can either set a maximum number of the relevant load cases or a percentage limit. If you use the percentage limit, all load cases are used that reach a specified percentage of the maximum result. That means the higher the percentage, the less load cases will be considered.

Section 2 ‘Considered Load Cases’

After you select the ‘Automatically’ option in section one, the selected load cases will be shown here in their groups. The combinations are created only in these groups without further mutual combinations.

Section 3 ‘Combination type’

If you select ‘Combine considered load cases’, all load cases are combined with each other once again in one group. The ‘Include considered load cases in groups’ option results only in combinations containing all load cases from this group (with different leading actions).

Section 4 ‘Examining Results’

In this section, you can select which results are used for the selection of the governing load case. Only selected result categories are used in the comparison. If you select the ‘Assign separately for each object’ check box, then the governing load cases can be set for selection by means of individual objects with certain results from the global deformation. Thus you can, for example, select the global deformation ux and analyze it only at Member 1. In addition, you can analyze uy only at Member 2. The selection is done in Section 5.

Section 5 ‘Examining Results of Objects’

In this section, you can select of which objects the results are to be analyzed for the load case reduction.

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RFEM Main Program
RFEM 5.xx

Main Program

Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements

RSTAB Main Program
RSTAB 8.xx

Main Program

The structural engineering software for design of frame, beam and truss structures, performing linear and nonlinear calculations of internal forces, deformations, and support reactions