Tributary area to ridge beam
AT = 13 * 20 = 260 ft2
Note that the dead loads calculated in Problem 2.1 were on a horizontal plane, so we use the horizontal distance of 13 ft instead of the hypotenuse.
Roof Live Load
Term Value Reference L0 20 psf (at 0:12) ASCE 7 table 4-1 R1 1.2 - 0.001AT ASCE 7 section 4.9.1 R2 1 (F ≤ 4) ASCE 7 section 4.9.1
Lr = (1.2 - 0.001 * 260) * 1 * 20 psf = 18.8 psf (pressure)
wLr = 18.8 psf * 13 ft = 244.4 lb/ft (distributed load on ridge beam)
