Repeat Problem $7\mathrm{.}5$ with the following: B$,=4$ ft$,$ B$2=10$ ft$,$

$4=8$ ft$,$ Ls $=12$ ft$,$ and the uniform load on the flexible area $=$

$25001$b$/$f$?.$ Determine the stress increase below point O at a

depth of $20$ ft$.$ Use Eg$.(7\mathrm{.}43)$ and us $=0.$