After you obtain the roof slope factor from those sections in asce 7 10 the balanced design snow load for the sloped roof can easily be calculated using equation 7 4 1.
Roof live load reduction example.
L r l o r 1 r 2.
Building live load reduction recognizing that the probability of supporting a large fully loaded tributary area is small.
Building codes permit reductions in the standard l 0 design live loads when the influence area ai k lla t is larger than 400 ft2 37 2 m2 as given in the following formulas.
The live loads for members supporting two or more floors are permitted to be reduced by a maximum of 20 percent but the live load shall not be less than l as calculated in section 1607 10 1.
R 1 1 for a t less than or equal to 200 psf r 1 1 2 0 001 a t for between 200 psf and 600 psf.
2attic loads may be included in the floor live load but a 10 psf attic load is typically used only to size ceiling joists adequately for access purposes.
Loads should be determined in accordance with this chapter.
Where l r shall not be less than 12 psf and not more than 20 psf.
The balanced snow load is applied everywhere where the roof structure is located.
The nature of roof live load is different from that of floor live load so the approach to reducing roof live load is different from that used for floor live load.
Roof live load reduction.
1 2d 1 0e l 0 2s when h loads are present they shall have 6.
Minimum uniformly distributed live loads adapted from sei asce 7 10.
The live load on a roof is the weight of any temporary objects on the roof.
Where d is floor dead load.
Roof live load may be reduced by the following equation.
However if the attic is intended for storage the attic live load or some portion should also be considered for the design of.
0 9d 1 0w a load factor of 1 6 when adding to load 7.
Where uniform roof live loads are reduced to less than 20 psf 0 96 kn m 2 in accordance with section 1607 13 2 1 and are applied to the design of structural members arranged so as to create continuity the reduced roof live load shall be applied to adjacent spans or to alternate spans whichever produces the most unfavorable load effect.
For uses other than storage where approved additional live load reductions shall be permitted where shown by the registered design professional that a rational approach has been used and that such.
Minimum design loads for buildings and other structures location uniform load psf.
0 9d 1 0e effect or 0 9 when resisting the load when permanent.
The requirement is presented in asce 7 05 4 9.
