1

General method for lateral and lateral torsional buckling of structural components in Eurocode 3

F. Bijlaard, M. Feldmann, J. Naumes, G. Sedlacek

2

Stability rules in Eurocode 3 Design of steel structures

Column buckling

Lateral torsional buckling

Interaction

Rules for stability assessment

Plate buckling x Plate buckling y Plate buckling

Interaction

General method stability

General method plate stability

3

Basic model for general method

EN

crit

EEE

NNNeM

=1

10

1=+R

E

R

E

MM

NN

=R

E

NN 2=

cr

R

NN

11

120 =

+

eMN

R

R

( )2.00 = R

R

NMe

( ) 11

11 2 =+

22

1

+

= ( )[ ]22.015.0 ++=

1.

2.

3.

4.

5.

6.

7.

8.

4

-value for different cross sectional resistances

5

-value determined by FEM calculations

6

-values

7

-values

8

Test evaluation for buckling about weak axis (buckling curve b)

9

Partial factor M acc. to EN1990 - Annex D

10

Basic model for lateral torsional buckling

11

Basic equation for lateral torsional buckling

12

Column buckling formula

13

Comparison between column buckling curve and lateral torsional buckling curve

14

Comparison with test results

15

M-values

16

Calculation steps for assessment of combined column-buckling - lateral-torsional buckling problem

1. step: in-plane :

2. step: out of plane:

3. step:

4. step:

5. step:

KdKult RE =,

dcritcrit x,,*

*0

*

0 =

crit

crit

crit

Kult

,= ( ) ,*0= ( ) ( )dKultdE xx , =

( ) ( )1,

=

M

dKultdEd

xx

17

Example for implementation

18

Eigen mode of example

19

Example with fin-plates

IPE 120S235

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Test results

21

Comparison between calculative and test results

22

Tests with haunched beams

23

Comparison between calculative and test results