Compression member: SHS / RHS calculator

Inputs in the worked example

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Worked example — results

• ✓ N* ≤ φNc

Method, formulas and assumptions

• Area (square corners) = 150*150-(150-2*6)*(150-2*6) = 3456 mm²
• I min = MIN(150*150^3-(150-2*6)*(150-2*6)^3,150*150^3-(150-2*6)*(150-2*6)^3)/12 = 1.196e+7 mm⁴
• r min = SQRT(1.196e+7/3456) = 58.839 mm
• λe short side = (MIN(150,150)-2*6)/6*SQRT(350/250) = 27.214
• λe long side = (MAX(150,150)-2*6)/6*SQRT(350/250) = 27.214
• kf (λey = 40, effective widths) = (2*(MIN(150,150)-2*6)*MIN(1,40/27.214)+2*(MAX(150,150)-2*6)*MIN(1,40/27.214)+4*6)*6/3456 = 1
• φNs = 0.9 kf A fy = 0.9*MIN(1,1)*3456*350/1000 = 1088.6 kN
• λn = (le/r)√kf √(fy/250) = 4.5*1000/58.839*SQRT(MIN(1,1))*SQRT(350/250) = 90.493
• αa = 2100*(90.493-13.5)/(90.493^2-15.3*90.493+2050) = 18.26
• λ = λn + αa·αb = 90.493+18.26*-0.5 = 81.362
• η = MAX(0,0.00326*(81.362-13.5)) = 0.22123
• ξ = ((81.362/90)^2+1+0.22123)/(2*(81.362/90)^2) = 1.2471
• Slenderness reduction αc = MIN(1,1.2471*(1-SQRT(1-(90/(1.2471*81.362))^2))) = 0.67114
• φNc = 0.67114*1088.6 = 730.63 kN
• Section properties from dimensions with square corners (published values include corner radii).

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