Textbook Problem

Design the tension members of the roof truss shown in Figure P3.8-4. Use, double-angle shapes throughout and assume $\raisebox{1ex}{$3$}\!\left/ \!\raisebox{-1ex}{$8$}\right.$-inch-thick gusset plates and welded connections. Assume a shear lag factor of U = 0.85. The trusses are spaced 25 feet. Use A572 Grade 50 steel and design for the following loads.

Metal deck: 4 psf of roof surface

Build-up roof: 12 psf of roof surface

Purlins: 6 psf of roof surface (estimated)

Snow: 18 psf of horizontal projection

Truss weight: 5 psf of horizontal projection (estimated)

a. Use LRFD.

b. Use ASD.