고체역학 (Beer) — Analysis and Design of Beams for Bending: Problem 5.84

5.84 Assuming the upward reaction of the ground to be uniformly distributed and knowing that the allowable normal stress for the steel used is 24 ksi, select the most economical wide-flange beam to support the loading shown. (From Fig. P5.84: Beam $AD$ has a total length of $12\text{ ft}$ with three $4\text{ ft}$ segments. Two concentrated downward loads of $200\text{ kips}$ each are applied at points $B$ and $C$, which are $4\text{ ft}$ and $8\text{ ft}$ from the left end $A$ respectively.)