Live Load Of Flat Roof

Roof load live load design is affected by the shape of the roof whether it is flat curved or pitched.

Live load of flat roof.

Axial forces from snow loads and roof live loads should usually not be considered simultaneously with an extreme wind load because they are mutually exclusive on residential sloped roofs. Further in most areas of the united states design winds are produced by either hurricanes or thunderstorms. D dead load l live load l r live roof load w wind load s snow load e earthquake load r rainwater load or ice water load. This downward imposed load on the home is also known as the snow load.

Flat roofs often can carry a higher live load than sloped roofs. To figure out the load on your roof take the depth of snow in feet and multiply it by the weight of a cubic foot of snow. If the snow weighs 10 pounds per cubic foot and there are 1 5 feet on the roof each square foot of the roof is getting 15 pounds of pressure. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow.

Load types loads used in design load equations are given letters by type. Roof loads are a downward vertical force on the home. For roofs that are flat and with ground snow loads lower than 20 pounds per square foot the roof snow load is equal to 70 of the product of the exposure thermal and importance factors and the ground snow load. Where snow isn t a problem the live load can come from people working on the roof and any equipment they take on to the.

Live loads on roofs table 1 3 gives lives loads on flat roofs sloping roofs and curved roofs. 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. Roofs of buildings used for promenade or incidental assembly purposes shall be designed for a minimum load of 400 kg m2 4 kn m2 or heavier it required. The north zone middle zone and the south zone are identified on the roof load zone map above.