Structures II

Problem $1(10$ points$)$

a$)$ Determine the ultimate moment capacity of a beam with dimensions $b=10in.$ and $d_{\text{e}\text{f}\text{e}\text{c}\text{t}\text{i}\text{v}\text{e}}=20$ in$,$ and that has two No$.14$ bars of tension$-$reinforcing steel.

Assume $d_{\text{g}\text{r}\text{o}\text{s}\text{s}}=23$ in$.,F_t=60$ksi, and $F_c^{\text{'}}=3$ksi.

b$)$ Assume the section is used as cantilever beam $15ft$ long, service loads are dead load $=250l\frac{b}{f}t$ and live loads $300l\frac{b}{f}t.$ Is the beam adequate bending? Calculate the ultimate moment capacity of the beam first.

Hint: see similar example in Schodek $530$pp