In RF-PUNCH Pro, I use the sector model to determine the load increase 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 load increase factor 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 increase 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 increase factor ß in our Knowledge Base .

Now, you can estimate in line with engineering practice whether this value is to be applied for the determination of the load increase 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 increase 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 load increase factor ß. See Figure 02. Thus, you can avoid values resulting from a singularity by individually specifying the load increase factor β.

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


Load increase factor ß Punching Singularity Critical control perimeter Shear force distribution

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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

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RFEM Concrete Structures
RF-PUNCH Pro 5.xx

Add-on Module

Punching shear design of foundations and slabs with nodal and line supports

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