Advanced Procedure for Effective Shape Calculation

In addition to the standard procedure described in the previous paragraphs for the calculation of the Effective Shape, also the Advanced Procedure described in EN 1993-1-3 art. 5.5.1(7) is supported.

This procedure does not use analytical formulas for calculating the critical local- and distortional buckling stresses of the different elements, but instead uses the values obtained by a numerical (stability) analysis.

When this setting is activated within the Cross-section, the user can input the minimal local- and distortional buckling stresses obtained from numerical analysis for the different effective shapes. These stresses are then used for the calculation of the effective widths and thicknesses.

 

The following provides an overview of the different steps:

1) Calculate the elastic buckling stresses and identify the corresponding buckling modes

2) Calculate the effective width(s) according to 5.5.2 for locally buckled cross-section parts based on the minimum local buckling stress

3) Calculate the reduced thickness (see 5.5.3.1(7)) of edge and intermediate stiffeners based on the minimum distortional buckling stress

4) Calculate overall buckling resistance according to 6.2 based on the effective cross-section from steps 2) and 3).

 

This method provides an alternative for cross-sections which have more complex shapes. It should however be noted that, due to the use of the minimal stresses, this procedure is quite conservative.