User`s Manual

Steel Portal Frame EC3 RUNET software

16.10.6 Buckling resistance of uniform members in compression

ΕΝ 1993-1-1:2005 § 6.3.1

Buckling resistance due to compression.

N

Ed



1

(ΕΝ 1993-1-1, 6.46)

N b

,

Rd

N b

,

Rd





Af y



M

1

for class 1, 2, 3 cross-sections (ΕΝ 1993-1-1, 6.47)

N b

,

Rd





A eff



M

1

f y

for class 4 cross-sections (ΕΝ 1993-1-1, 6.48)

The reduction factor



is determined from the non-dimensional slenderness



1



 

1

(ΕΝ 1993-1-1, 6.49)

  

2





2

 

0 .

5 1













0 .

2









2





Af y

;

N cr





2





2

;





l eff

N cr i



non-dimensional slenderness

,

;

i



I

A

N

elastic critical buckling load,

cr

Lcr equivalent buckling length,

λ slenderness, i radius of gyration.

The imperfection factor

 that corresponds to the appropriate buckling curve ao,a,b,c,d should be obtained from Table 6.2 of Eurocode 3, ΕΝ 1993-1-1:2005:

Buckling curve a o a b C d

Imperfection factor α 0.13 0.21 0.34 0.49 0.76

Equivalent buckling lengths Lcr/L

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Steel Portal Frame EC3 RUNET software

Table 6.2 ΕΝ 1993-1-1:2005 Selection of buckling curve of a cross-section

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