Beam-columns - The Behaviour and Design of Steel Structures to EC3 - page 333

1 − N Ed / N cr , y
1 − χ y N Ed / N cr , y =

1 − 200 / 1417
1 − 0.693 × 200 / 1417 = 0.952

µ y = TA.1

µ y
( 1 − N Ed / N cr , y )

1
C yy

k yy = C my C mLT

0.952
1 − 200 / 1417 ×

1
0.990 = 1.091

= 0.975 × 1.0 × TA.1

N b , y , Rd + k yy M y , Ed

N Ed

M c , y , Rd = 200 900 + 1.091 × 45.0

132.8

= 0.222 + 0.370 = 0.592 < 1 6.3.3(4)

and the member resistance is adequate.

7.7.3 Example 3 - checking the minor axis in-plane
resistance

Problem. The 9m long two span beam-column shown in Figure 7.19c has a fac-
tored design axial compression force of 200kN and a factored design uniformly
distributedloadof3.2kN/mactingintheminorprincipalplane.Thebeam-column
isthe254 × 146UB37ofS275steelshowninFigure7.19a.Checktheadequacy
of the beam-column.

Simplified approach for cross-section resistance.

M z , Ed = 3.2 × 4.5 2 / 8 = 8.1 kNm.

TheflangeisClass1underuniformcompression,andsoremainsClass1under
combined loading.

c w /( t w ε) = ( 256.0 − 2 × 10.9 − 2 × 7.6 )/( 6.3 × 0.924 ) = 37.6 < 38 T5.2

and the web is Class 2.Thus the overall cross-section is Class 2.

M c , z , Rd = 275 × 119 × 10 3 / 1.0 Nmm = 32.7 kNm.

6.2.5(2)

200 × 10 3

47.2 × 10 2 × 275 / 1.0 + 8.1 32.7 = 0.402 < 1

6.2.1(7)

and the cross-section resistance is adequate.