sm7 13

________________________________________________________________________
PROBLEM (7.13) An S 150 x 26 steel I beam (see Table B.8) is simply supported on a
span L and carries a uniform load of intensity w.
(a) Determine the maximum value of w.
(b) Determine the width of a solid rectangular section of the same 152-mm depth to replace
the I shape.
(c) Compare the areas of the two sections.
Given: L = 10 in., all
σ
= 120 MPa
SOLUTION
2
wL
A
s =3270 mm2
w
2
wL 10 m
S =144x10-6
S150x26
152 mm
(a) 2
max 8
all MwL
SS
σ ==
66
22
88(144 10 )(120 10 )
(10)
all
S
wL
σ
−
××
== 1.38 kN m
=
(b) 2
6
bh
S=
2
6(0.152)
144 10 6
b
−
×= , 37.4bmm
=
(c) 22
3270 37.4(152) 5685
sr
AmmA m===
b
152 mm
m
Thus,
1.74
rs
AA=
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or
instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other
reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States
Copyright Act without the permission of the copyright owner is unlawful.