1
A
B
wD = 850 lb/ft
wselt wt
wL = 1150 lb/ft
32 ft
Practice Quiz 8
Note: No aids are allowed for part 1. One side of a letter sized paper with notes is allowed
during part 2, along with a silent, non-programmable calculator. There are reference charts on
pages 2-6 for part 2.
Clearly show your work and answer.
Part 1) Worth 5 points (conceptual questions)
Part 2) Worth 45 points
(NOTE: The loading type [ex, live, dead, wind...] and sizes can
and will be changed for the quiz with respect to the beam
diagrams and formula provided.)
A wide flange beam of A992 steel (Fy = 50 ksi, E = 30 x 103 ksi) is
needed to span 32 ft and support uniformly distributed loads of
850 lb/ft of dead load (from materials), the self weight, and 1150 lb/ft of
linearly distributed live load. The beam is simply supported with a maximum unbraced length of 11 ft.
a) Select the most economical beam based on flexural strength using the provided chart (including self
weight). Assume that the dead load will determine the location of the maximum bending moment and
superimpose the live load moment at that location.
b) If a W21 x 44 (A = 13.0 in.2, d = 20.66 in., tw = 0.35 in., bf = 6.50 in., tf = 0.45 in., Ix = 843 in.4) is
chosen, is it adequate for shear?
c) Determine the moment of inertia required such that the total [or live load or dead load] deflection,
ignoring self weight, does not exceed 1.25 inches.
Answers – Not provided on actual quiz!
a) Mu = 248.3 k-ft, use W14x48 (Mu* > 250.5 k-ft)
b) Vu = 36.0 k, Vn = 216.9 k, OK c) Ireq’d = 897 in4
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