Question

2. Verify that a built-up ASTM A572 Grade 50 (Fy - 345 MPa) column with PL 205 x 25 mm flanges and PL 380 * 6 mn web is sufficient to carry a dead load of 300 kN and live load of 900 KN in axial compression. The column, having an unbraced length of 8 meters, is braced at the midpoint about the weak axts, the ends are pinned in both axes. (Use ASD, 15 pts)

Answer 1

Ic 205 f 125 1380 k 99.5 All Dimensions are in mm * Given Data: A572 Grade 50 steel Fy= 345 MPa Fu= 450 MPa Kl=em=8000 mm. 1) Loads Po - 300 kN (Dead load). PL = 900kN (Live load) Pa = Ppt P2 = 300+900 P= 1200 KN 2) selection properties 5 A=(2X205X25) +(380x6). 1A= 12530 mm? → Ix= (205x(430) (@osuzo?}-{84495x1350 IX=448.28 X 100 mmt

380x600 + 6 $) 8x = V 18y こ 0-658 CylFe), Fy: Iy = fax (205) x 25 12 12 Iy= 35-903 X 100 minit ve 448.28x108 12530 18x = 189:15 mm By = Iy 35.903 X10 12530 = 53.53 mm Now, kl 8000 42.29 8x 189.15 kle (8000/2) 74.72 ry 53.53 :. consider maximum (kl) = 74.72 3.) compressive strength:- * Fe TT? x 2,00,000 = 353.55 MPa (kl) (74.722 Fe = 353.55 MPa (345/353-55) =0-658 X 345. TE 2 For=229.32 MPa

* Now, ASD allowable load Pa = Eco x Ag 229.32 X 12530 1.67 : Pa= 1720-58 KN Here, 1720-58 KN > 1200 KN so, the load is safe and the material is also safe. : The section can bear the given load.

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