Cause (in general)

This error is always related to an inconsistency in the dimensions of the used cross-section(s). Resulting in cross-section classifications, imperfection factors, effective properties, … not being calculated automatically.

Example 1:

An RHS-section is used to create an elliptical cross-section. But because r0 (=25mm) equals B/2 (=50mm/2), the cross-section classification in the weak direction cannot be performed.
Solution: set B= 51mm or set r0 to 24mm.

Example 2:

Some cross-section shapes are associated with cold-formed sections, like these in the list below:

When the option ‘Automatic calculation’ is selected, Diamonds calculates the general, elastic (except T_wm) and the plastic properties of the cross-section.
But Diamonds cannot calculate the effective and design properties for these cross-section shapes. These shapes are in Diamonds because manufacturers (Joris Ide, Brausa, Sadef, …) provided us with lists of common cross-sections with their dimensions and effective properties. So although you can play around with the dimensions, Diamonds is not capable of calculating the effective properties!

So if you want to perform a steel verification on these cross-section shapes, you should:

• Check the option ‘Automatic Calculation’. This way the general, elastic and plastic properties are calculated.
• Uncheck the option ‘Automatic calculation’. This way you can adjust the value of T_wm in the tab page ‘Elastic’.
• Define all the properties in the tab page ‘Effective’.
• Define all the properties in the tab page ‘Design’.