Use A36 steel and select structural tees for the top chord of the welded roof truss shown in the figure below. All connections are made with longitudinal plus transverse welds. Assume a connection length of 11 inches. The spacing of trusses in the roof system is 13 feet 6 inches. Design for the following loads. Snow: 20 psf of horizontal projection Roofing: 12 psf MC 8 x 8.5 purlins Truss weight: 1000 lb (estimated) 3'-0" 3 x 10'-0" 30'-0" For A36 steel: Fy = 36 ksi, F₁ = 58 ksi. Use the table below. Shape Ag "min 18 in.2 in. in. WT 5 x 13 3.81 1.36 1.06 WT 5 x 11 3.24 1.33 1.07 WT 5 x 9.5 2.81 0.874 1.28 WT 5 x 8.5 2.50 0.844 1.32 Check My Work Feedback Interior joint load: 3 30.15 30 Snow: 20(10) (13.5) = 2,700 lb Roofing: 12(10) (30.15/30) (13.5) = 1,628 lb Purlins: 8.5(13.5) 114.8 lb = Truss weight: 1000/3 = 333.3 lb == (The assumption that the truss weight is distributed equally to the joints is approximate but is consistent with the approximate nature of the estimate of total truss weight.)