고체역학 (Beer) — Analysis and Design of Beams for Bending: Problem 5.90

5.90 Beams $AB, BC,$ and $CD$ have the cross section shown and are pin-connected at $B$ and $C$. Knowing that the allowable normal stress is $+110\text{ MPa}$ in tension and $-150\text{ MPa}$ in compression, determine (a) the largest permissible value of $P$ if beam $BC$ is not to be overstressed, (b) the corresponding maximum distance $a$ for which the cantilever beams $AB$ and $CD$ are not overstressed.