1
the top flange of the W18x50 and a 3 ½ x 3 x 3/8 angle is
attached with the long leg up at the lower left as shown.
Determine the location of the centroid, and the Ix and Iy about
the major centroidal axes using the cross-sectional properties
given in the steel tables for standard rolled shapes (see
Appendix).
Problems: from Onouye, Chapters 7 & 9
Notes: Problems marked with a * have been altered with respect to the problem stated in the text.
Multiframe4D or other methods may be used for V & M diagrams and maximums.
*
Partial answers to check with:
x
ˆ
= -0.0805 in,
y
ˆ
= 11.99 in and must be calculated using the table,
Ix = 1578.8 in.4, Iy = 393.1 in.4,,rx = 7.40 in, ry = 3.69 in
*
Partial answers to check with: Sreq’d
43.64 in.3, fv = 5.5 ksi
*
Partial answers to check with: Sreq’d
74.5 in.3, fv = 58.2 psi
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(flexural and shear stress)
sawn timber
2.4 k/ft
A992 steel (Fb = 33 ksi).
steel
*The load is changed to 2.4 k/ft and the depth is not
restricted. Also find the maximum shear stress, fv.
Assume A992 steel (FY = 50 ksi, Fb = 33 ksi).
*The load is changed to 180 lb/ft. Assume Douglas fir-
larch No. 2 (Fb = 1450 psi). Also find the maximum
shear stress, fv.
(flexural and shear stress)
(20%)
(10%)
(10%)
180 lb/ft
L3 ½ x 3 x 3/8
*Also calculate the radius of gyration, rx and ry.
(centroid and moment of inertia)
