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Elastic modulus, Zy(cm3) 1570

Plastic modulus, Sx(cm3) 4690

Area of section, A (cm2) 300

BS 5950-1: 2000

Web thickness, t = 18.5< 40 mm, py= 265 N/mm2

Flange thickness, T = 30.2 < 40 mm, py= 265 N/mm2

The parameter, Flange, b/T = 6.54 < 9 Class 1 PlasticWeb, d/t = 15.7 < Class 3 Semi compactHence, the section is categorized as semi compact.

Table 9

Table 11

Effective length

Assume partially restrained in direction at both ends

LEx= LEy= 0.85L = 2975 mm

Slenderness ()

Column curve

Rolled H-section (Thickness 40mm)

Buckling about x-axis >> Table 24, curve (b)

Buckling about y-axis >> Table 24, curve (c )

Table 23

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Compressive strength

x-axis:

Py = 265 N/mm

2

Curve (b) >> pcx= 263 N/mm2

Y-axis:

= 29.17Px = 265 N/mm

2

Curve (c ) >> pcy= 246 N/mm2

Get the minimum pc, so the pc= 246 N/mm2

Compression resistance (Pc)

Pc= Agpc

Pc= (300 x 102)(246 x 10-3) = 7380 KN > Fc[Safe!]

Overall buckling check

Since, Mx= 0, My= 4.72 KNm,

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For External column

Axial

The maximum axial load, Fc= (2025.99) + (572.77 + 31.68 + 338.94) + (60 x 3.5 x

10-2) = 2971.48 KN

Pc= Agpc, Assume pc= 150 N/mm2 and Pc= 2971.48 KN

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2971.48 = Agx 150

Ag= 198.10 cm2

Use UC 254 x 254 x 167

Nominal moments

Mx= 0 (the loads are balanced about x-x axis)

My= [572.77 x (100 + t/2)]/2

= [572.77 x (100 + 19.2/2)]/2 = 31.39 KNm

Element UC 254 x 254 x 167

Depth of section, D (mm) 289.1

Web thickness, t (mm) 19.2

Flange thickness, T (mm) 31.7

Ratio for buckling flange, b/T 4.17

Ratio for buckling web, d/t 10.4

Radius of gyration, rx(cm) 11.9

Radius of gyration, ry(cm) 6.79

Elastic modulus, Zy(cm3) 741

Plastic modulus, Sx(cm3) 2420

Area of section, A (cm2) 212

BS 5950-1: 2000

Web thickness, t = 19.2 < 40 mm, py= 265 N/mm2

Flange thickness, T = 31.7 < 40 mm, py= 265 N/mm2

The parameter,

Table 9

Table 11

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Flange, b/T = 4.17 < 9 Class 1 PlasticWeb, d/t = 10.4 < Class 3 Semi compactHence, the section is categorized as semi compact.

Effective length

Assume partially restrained in direction at both ends

LEx= LEy= 0.85L = 2975 mm

Slenderness ()

Column curve

Rolled H-section (Thickness 40mm)

Buckling about x-axis >> Table 24, curve (b)

Buckling about y-axis >> Table 24, curve (c )

Compressive strength

x-axis:

Py = 265 N/mm

2

Curve (b) >> pcx= 258 N/mm2

Y-axis:

= 43.81Px = 265 N/mm

2

Curve (c ) >> pcy= 237 N/mm2

Get the minimum pc, so the pc= 237 N/mm2

Table 23

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Compression resistance (Pc)

Pc= Agpc

Pc= (212 x 102)(237 x 10-3) = 5024.4 KN > F

c[Safe!]

Overall buckling check

Since, Mx= 0, My= 31.39 KNm,

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