Figure 10-39 shows a long-span, flat roof designed using bar20 ft), beams, and girders. The snow load is 20 psf, and the dead load, including the weight of the joists(but not of the beams and girders), is 20 psf. Because ponding could be a factor, the total load deflection is limited to L/360.Use F,= 36 ksi steel for the beams and f3 + 50ksi steel for the girders .

Fig: 1