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In RF-PUNCH Pro, I use the sector model to determine the load increasing factor ß. However, due to singularities in the surface internal forces, the ß-values are sometimes set too high. How can I handle this?


It is correct that singularities in the FE calculation also affect the results of the determination of the LO ratio ß by means of the sector model.

Smooth ranges applied in the RFEM model have no influence on the determination of ß in RF-PUNCH Pro.

If the results in the critical control perimeter are influenced by the singularities, you can select the Load increasing factor ß yourself. You can display the "Shear force in sectors" in the result navigator of the RF-PUNCH Pro Results window (Figure 01). The maximum value of all sectors is used to determine the ß-factor.

You can also find an article describing the load increasing factor ß in our Knowledge Base .

Now, you can estimate by the engineer whether this value is to be applied for the determination of the LO-factor, or not. If not, you as the user can evaluate the distribution of the shear force in the sectors (see Figure 01) and determine the load increment factor ß yourself (averaged value of the considered sector / averaged value over entire control perimeter).

In the input dialog box "1.5 Nodes of Punching Shear" in RF-PUNCH Pro, you can directly specify the loading increase factor ß. See Figure 02. Thus, you can avoid values resulting from a singularity by individually specifying the load increasing factor β.

The following is important:
The program can not provide automatic control for this. These points must always be individually checked and evaluated by the designer.


Load increment factor ß Punching Singularity Critical perimeter Shear force distribution

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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

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