Flexural Buckling

The Flexural Buckling Check is executed according to EN 1993-1-1 art. 6.3.1.

Buckling Curve

Table 6.3 regarding the buckling curves is revised as follows:

- I-section (formcode 1) with fabrication Rolled:

Condition		Other fy	fy =  460 N/mm^2
if h/b >1,2 and tf <= 40 mm   and 40 < tf <= 100 mm	Curve yy Curve zz   Curve yy Curve zz	a b   b c	a0 a0   a a
if h/b <= 1,2 and tf <= 100 mm	Curve yy Curve zz	b c	a a
for any h/b and tf > 100 mm	Curve yy Curve zz	d d	c c

Any other cases not covered by the above:

Curve yy = d

Curve zz = d

- I-section (formcode 1) with fabrication Welded:

tf <= 40 mm   tf > 40 mm

Curve yy Curve zz   Curve yy Curve zz

b c   c d

- RHS (formcode 2) or CHS (formcode 3) with fabrication Rolled:

Curve yy = a

Curve zz = a

In case fy = 460 N/mm^2 this becomes:

Curve yy = a0

Curve zz = a0

- RHS (formcode 2) or CHS (formcode 3) with fabrication Cold-Formed:

Curve yy = c

Curve zz = c

- RHS (formcode 2) with fabrication Welded:

Curve yy = b

Curve zz = b

- RHS (formcode 2) or CHS (formcode 3) with any other fabrication:

Curve yy = d

Curve zz = d

- Any section of the group:

Curve yy = b

Curve zz = b

- Channel section (formcode 5) or T-section (formcode 6) or full-rectangular (formcode 7) or full circular (formcode 11) with any fabrication:

Curve yy = c

Curve zz = c

- L-section (formcode 4) with any fabrication:

Curve yy = b

Curve zz = b

- Asymmetric I-section (formcode 101): This follows the same rules as a symmetric I-section. For the conditions b is taken as the max of Bt and Bb and tf is taken as the max of tt and tb.

- From the group the SFB, IFBA, IFBB sections follow the same rules as a welded I-section (independent of fabrication). For the condition tf is taken as the max of to and tu.

- From the group the THQ section with any fabrication:

Curve yy = b

Curve zz = b

- Any section from the group follows the same rules as a welded I-section (independent of fabrication). For the condition tf is taken as the max thickness of any of the flanges.

- Any section of the or or groups (which do not meet any of the other rules):

Curve yy = c

Curve zz = c

- Any other section i.e. not covered by any of the above:

Curve yy = d

Curve zz = d

The user can manually overrule the buckling curve within the Cross-section.

For non-prismatic members with cross-sections that are not listed in Table 6.2 all generated sections will receive the user inputted values of the buckling curves of the first section in the span.

Buckling Length

For the calculation of the buckling length, reference is made to chapter ""Annex B: Calculation of buckling ratio"".

The buckling properties for a VARH element are calculated by using the critical Euler force for this member (see chapter “"Calculation of critical Euler force"”).