Beer & Johnston — Analysis and Design of Beams for Bending: Problem 5.146

5.146 Two cover plates, each $\frac{5}{8}$ in. thick, are welded to a W30 $\times$ 99 beam as shown. Knowing that $l = 9\text{ ft}$ and $b = 12\text{ in.}$, determine the maximum normal stress on a transverse section (a) through the center of the beam, (b) just to the left of $D$.