Question

Find the minimum required thickness tmin for a steel pipe column of length L-3.6 m and [25 pts.] Q-3 outer diameter d=160 mm supporting an axial load P-240 kN (See Fig. below). The column is fixed at the base and free at the top. (Use E 200 GPa and Sy-250 MPa.) -The critical 1loading is calculated from Euler's formula, L 2EI Per er (Le/r Le equivalent length ka/

Answer 1

grve n ア=240 KN 7.2m KL-(2) Syective length Le ts ra tio Critical slenderness (200 XDMFa - 25.66 RITTE KL 250 MPa 4 64 Tld d-2t Aこ 4 A

ferst trial T (6o)" (60-14] -q.866X10 ot 64 A = -3365mm (r60(160-14- 9.S66 X106 5415 ma 3365 column slerdermess mtio KL- 2(3.6) - 133 5415 vratio Ut than The critical (anger is this Since the obtain slendeness ratio 50 allowable sbress allos 0.8T7Te -0.871 LL8 0 13e)2 alo 497 ksi allow58:6 MPa The allouable axial load is = allowA (58.6)(3365) Tallou Pallow196 KN Z 240 KN Take t8.9mm 16060-17-8) A = -4234. 78 mma 20989 xI06 4224 18 - 53 5 mm KL(2(3 6) , 134.6 53.5X10 T2x2DOxIO (134 6)3 allouw 0.811 allow512 MPa Pallousallos A = (51.4224-18) "Pallous241 KN