Using the load Table $5\mathrm{.}40$ given in the handouts $($Chapter $5$ excerpt from LRFD Steel Design and Table $5\mathrm{.}40)$ or Table $18\mathrm{.}2$ in your textbook and select an open$-$web steel joist for the following floor systems and loads:

Joist spacing $=3ft$

Span length $=21ft$

Loads are dead load $=20$ psf$,$ live load $=40$ psf and there is a $3^{\text{'}\text{'}}$ concrete floor slab.

Joist spacing $=3ft$

Span length $=28ft$

Loads are dead load $=20$ psf$,$ live load $=40$ psf and there is a $3^{\text{'}\text{'}}$ concrete floor slab.