Problem $3\mathrm{.}17$

Use LRFD and design tension members of the truss loaded as shown in Figure below. Use double$-$angle shapes throughout and assume $10mm$ thick gusset plates and welded connections. Assume a shear lag factor of $U=0\mathrm{.}80.$ The trusses are spaced at $9m.$ Use A$36$ steel and design for the following loads.

Metal deck: $192$kPa of roof surface

Built$-$up roof: $576$kPa of roof surface

Purlins: $144$kPa of roof surface $($estimated$)$

Snow: $960$kPa of horizontal projection

Truss weight: $240$kPa of horizontal projection $($estimated$)$

LSG$16$