897_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

# 897_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

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SECTION 11.9 Design Formulas for Columns 891 Solution 11.9-4 (1) T RIAL VALUE OF Upper limit: with (2) T RIAL VALUE OF AREA A ± P s allow A ± 7273 mm 2 Try s allow ± 110 MPa s allow max ± 150 MPa s allow max ± s y n 1 L r ± 0 n 1 ± 5 3 s allow L c r ± A 2 p 2 E s y A 2 p 2 E s y ± 125.664 E ± 200 GPa s y ± 250 MPa L ± 4.25 m P ± 800 kN K ± 1 (3) T RIAL COLUMN (4) A LLOWABLE STRESS FOR TRIAL COLUMN s allow ± 103.9 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 ± 1.879 n 1 ± 5 3 + 3 a K L r b 8 a A 2 p 2 E s y b ² a K L r b 3 8 a A 2 p 2 E s y b 3 L r ± 83.170 L r 6 L c r A ± 8580 mm 2 r ± 51.1 mm W 250 * 67 Problem 11.9-3 Determine the allowable axial load P allow for a steel wide-flange column with pinned ends (see figure) for each of the following lengths: L ± 10 ft, 20 ft, 30 ft, and 40 ft. (Assume E ± 29,000 ksi and .) s Y ± 36 ksi W 10 * 60 Problem 11.9-4 Select a steel wide-flange column of nominal depth 250 mm. (W 250 shape) to support an axial load P ± 800 kN (see figure). The column has pinned ends and length L ± 4.25 m. Assume E ± 200 GPa and ( Note : The selection of columns is limited to those
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Unformatted text preview: listed in Table E-1(b), Appendix E.) s Y ± 250 MPa. Solution 11.9-3 Steel wide-flange column Pinned ends ( K ± 1). Bucking about axis 2-2 (see Table E-1a). Use AISC formulas. L c ± 126.1 r ± 324.in. ± 27.0 ft Eq. (11-76): a L r b c ± A 2 p 2 E s Y ± 126.1 E ± 29,000 ksi s Y ± 36 ksi a L r b max ± 200 W 10 * 60 A ± 17.6 in. 2 r 2 ± 2.57 in. L 10 ft 20 ft 30 ft 40 ft L/r 46.69 93.39 140.1 186.8 n 1 (Eq. 11-79) 1.799 1.894--n 2 (Eq. 11-80)--1.917 1.917 (Eq. 11-81) s allow / s Y 0.5177 0.3833--(Eq. 11-82) s allow / s Y--0.2114 0.1189 s allow (ksi) 18.64 13.80 7.610 4.281 ± A s allow P allow 328 k 243 k 134 k 75.3 k 11Ch11.qxd 9/27/08 2:27 PM Page 891...
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## This note was uploaded on 12/22/2011 for the course MEEG 310 taught by Professor Staff during the Fall '11 term at University of Delaware.

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