The truss shown in the figure below is one of several roof trusses spaced at 20 feet apart. Purlins are located at the joints. The weight of the roofing material is 5 psf, and the snow load is 15 psf of horizontal projection of the roof surface. The self-weight of the truss (including purlins) is estimated to be 10 psf of horizontal projection of the roof surface. Use LRFD and design the lightest square HSS for the most critical top chord members of the truss using all mandatory and recommended criteria. 15'-0 6 @ 15'0"9" The truss shown in the figure below is one of several roof trusses spaced at 20 feet apart. Purlins are located at the joints. The weight of the roofing material is 5 psf, and the snow load is 15 psf of horizontal projection of the roof surface. The self-weight of the truss (including purlins) is estimated to be 10 psf of horizontal projection of the roof surface. Use LRFD and design the lightest square HSS for the most critical top chord members of the truss using all mandatory and recommended criteria. 15'-0 6 @ 15'0"9"