"Prob. $6\mathrm{.}4-13.$ A structural designer wishes to locate the

roller support $B$ such that the beam $AD$ in Fig. P$6\mathrm{.}4-13$ will

have the same maximum magnitude of positive moment and

negative moment when subjected to concentrated loads $P_A$

and $P_C$ acting on the beam as shown. Once the overhang

length $b$ has been determined, the designer must choose an

appropriatc beam to satisfy a flexural stress allowable of

${}_{\text{a}\text{l}\text{l}\text{o}\text{w}}($tension or compression$).($a$)$ Determine the overhang

length $b.($b$)$ From Table D$\mathrm{.}2,$ select the best wide$-$flange

section for this application.