Problem No$.2.(50$ points$)$

The roof rafters shown are spaced $2ft.$ o$.$c$.($there are more than $3$ rafters in the roof$).$

Blocking against lateral stability is provided at the supports and the center of the rafter.

$DL=20$ psf along rafter; $SL=22$ psf on horizontal plane; in addition a mechanical system $(1$kip $)$ is attached to the center of the Rafter and is considered as dead$-$load.

Use ASD Design criteria.

The $2$ X $12$ Roof Rafters are Beech$-$Birch$-$Hickory $-$Select Structural

Rafter slope $6$:$18$

$MC=19\%$; Temp.$=100$F; If not specified assume adjustment coefficient Cx $=1\mathrm{.}0$

Determine the total Loads along the rafter slope. $($Use this load for design check$).$

Determine the total Loads on the horizontal plane $($Do not use this load for design check$)$

Check if the $212$ Rafter is adequate for bending stress.

Check if the rafter is adequate for shear without the notch and with the notch at the ridge beam.

Check if bearing in the $24$ top plate at the stud wall is adequate.

The top plate is a $2$X$4$ Douglas Fir Larch No $1.$

Check deflection against $\frac{L}{240}.$