906_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

906_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

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Problem 11.9-16 A W 250 67 steel wide-flange column with pinned ends carries an axial load P . What is the maximum permissible length L max of the column if (a) P ± 560 kN, and (b) P ± 890 kN? (Assume E ± 200 GPa and .) s Y ± 290 MPa * 900 CHAPTER 11 Columns Solution 11.9-16 For each load, select trial values of the length L and calculate the corresponding values of This solution show only the successful trial. (a) s allow ± 65.45 MPa s allow ± s y a K L c r b 2 2 n 2 a K L r b 2 n 2 ± 23 12 Try L ± 6.41 m L r ± 125.440 L r 7 L c r P ± 560 kN P allow L c ± r A 2 p 2 E s y L c ± 5.962 m L c r ± 116.676 L max ± 200 r r ± r 2 r 2 ± 51.1 mm A ± 8580 mm 2 W 250 * 67 E ± 200 GPa s y ± 290 MPa K ± 1 (b) ; Therefore L max ± L L max ± 4.76 m P allow ± A s allow P allow ± 891 kN s allow ± 103.85 MPa s allow ± s y 1 n 1 1 ² a K L r b 2 2 a A 2 p 2 E s y b 2 ¥ n 1 ± 1.902 n 1 ± 5 3 + 3 a K
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Unformatted text preview: L r b 8 a A 2 p 2 E s y b a K L r b 3 8 a A 2 p 2 E s y b 3 Try L 4.76 m L r 93.151 L r 6 L c r P 890 kN ; Therefore L max L L max 6.41 m P allow A s allow P allow 561.6 kN Problem 11.9-17 Find the required outside diameter d for a steel pipe column (see figure) of length L 20 ft that is pinned at both ends and must support an axial load P 25 k. Assume that the wall thickness t is equal to d /20. (Use E 29,000 ksi and .) Probs. 11.9-17 through 11.9-20 s Y 36 ksi t d 11Ch11.qxd 9/27/08 2:27 PM Page 900...
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