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A double angle discontinuous strut to carry a factored axial comp of 178kN the length of strut between centre of intersection 9s 3.08m design the member for following two cases1)angle packed back
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to back in opposite site of gusset plate 2)Angle place same side of gusset

Angle are tack bolted & provided wotj min of two bolts

Given P=178KN

l=3.05m

leff=0 8×3.08

=2464mm

consider fed=150mpa

Pd=Ae×fcd

178×103=Ae×150

back to back connection Ae=1186.67mm2 Area required

Area of each angle=1186.672=56.33mm2

Assume fcd=90mpa

Pd=Ae×fcd

178×103=Ae×90

Ae=1977.78mm2

Area of each angle = 1977.782=988.88mm2

select Anlge=×80×50×10

A=1202mm2

Area provided =1202×2=2404mm2

enter image description here

γxx=$IxxA γuu=IuuA

Iuu=22.10×104mm4--steel table

Iyy1=Iyy1+Iyy2

=2(Iyy+Ah2)

=2(22.10×104+1202×(102+13.2)2)

Iyy=1.23×106mm6

γyy=1.23×1062404

γyy=22.63mm

λ=kLγyy=246422.69=108.56

100        107

108         fcd

110          94.6

110100110106.56=94.610794.6fcd

101.44=12.494.6fcd

-17.856=946-10fc

fcd=96.38 N/mm2

Pd=A×fcd

=2404×96.38

Pd=231.71 KN =178 KN hence safe

Case second

angle connect same side of gusset plate

enter image description here

Iyy=Iyy1+Iyy2

=2(22.1×104+1202(17.2)2)

Iyy=860×87×103mm4

γyy=860.87×1032404=18.92mm

λ=246418.92=130.20

130 743 140=130140130.20=66.274366.2fcd

fcd=74.13N/mm2

Pd=2404×74.13

=178.22KN>178 hence safe

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