Hint:

$1-$ Calculate the required plastic modulus $(Z)$ from the design bending moment and

allowable stress $($Required Z$=$M$/$Fb$).$

$2-$ calculate the required moment of inertia $($I$)$ from the distributed loads and the

allowable deflection $($Figure $7).$ The required I value should be determined for $1)$

$DL+LL,$ and $2)$ LL $,$ as the deflection criterion is different for each.

$3-$ Use the maximum of the two I values to determine the required I $.$

$4-$ Enter Table $1$ with the required $Z$ and I and select the section whose $Z$ and I are

greater than the required values.

Figure $7-$ Required I values