Roof Live Load Determination

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Roof live load determination.

For dead loads you are correct. In asce 12 7 2 and 12 14 8 1 as referenced in section 1613 1 definition of w item 4 is deleted and replaced with the following. You need to supply the following information. However in my practice i typically use the horizontal run of the roof for both types of load.

Victor staley a building official in the town of brewster mass responds. The roof shall be designed for the live load indicated in table r301 6 or the snow load indicated in table r301 2 1 whichever is greater. This issue of live load vs. Ang alive del 0000 oddo problems determine the roof live load le for members rj1 rb1 rb2 rb3 and column b 2 in the framing plan given in problem 4 a rj1.

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. Used but they typically defined the load cases or combination stress or strength limits and deflection limits. Load types loads used in design load equations are given letters by type. To do this i use conservative too heavy dead loads and full snow loads regardless of pitch.

Both dead load and live load are expressed in pounds per square foot. The dead load of a typical asphalt shingled wood framed roof is about 15 pounds per square foot. A clay tiled roof may have a dead load. Boca also allows you to reduce the snow load for roofs with slopes greater than 30 degrees presumably because snow will slide or blow off steeply pitched roofs.

If your roof is pitched enter the length and width of the flat area covered by the roof. Unlike the trussed roof live load and dead load of the rafters and ceiling joists must be accounted for as separate systems. To calculate the weight of snow on a roof use the first two sections of our snow load calculator. Length and width of your roof.

W s weight of snow to be included as effective. Since it is possible to use the attic for storage the live load of the attic floor is set at 20 psf according to code. Ground snow load might seem somewhat confusing until you read the basic premise that is identified in irc section r301 6 which states. The live load is determined by applicable building codes and usually consists of components for snow load and the estimated weight of persons and equipment required to maintain the roof.

1 for places of public assembly live loads in excess of 100 psf and for parking garages 0 5 for other live loads ƒ 2 0 7 for roof configurations such as sawtooth that do not shed snow off the structure 0 2 for other roof configurations 02 fanella chapter 02 p005 030 indd 7 26 07 18 7 15 pm. The load increases with the use of heavier roofing material. Where flat roof snow load p f exceeds 30 psf the snow load included in the effective seismic weight shall be calculated in accordance with the following equation. W s 0 20 0 025 p f 0 20 p f.

Technically you should use the actual rafter length when adding up the weight of roofing materials. Probleme for the given roof framing plan define the trutary width for members rur.