Ground Snow Load To Roof Snow Load Conversion

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Ground snow load to roof snow load conversion. Snow load thickness density the result snow load or the pressure exerted by the snow has the units of kn m or lbs ft. This web based application is made freely available courtesy of the advertisements displayed on this page. Increasing the snow load factor from 1 6 to 2 0 increases the reliability index to roughly 2 0. From eave to ridge w.

Importance factor i s. Or the 25 psf snow load could be entered as a roof snow load with the unbalanced snow loading option turned off. Our recommendations on ground to roof conversion factors incorporates what we consider to be the most accurate information on the topic. In my region on cape cod we have a ground snow load design of 25 psf which is a greater design load than the live load 12 psf to 20 psf over an entire roof system.

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. The snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load. Ground snow load pg. Length of low roof ll.

Snow weight length width cos pitch snow load the weight of snowis measured in kgor lbs. Version 0 1 0 september 13 2020. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. Length of high roof lu.

In other words on a steep roof less material would be stacked in a concentrated area at one time to avoid having it slide off. Ground snow load s s. Figure 7 1 pages 84 85 and table 7 1 page 92. In our case let s assume that our structure has a flat roof roof slope 5.

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. The flat roof snow load is calculated using formula 7 3 1. Roof snow load nbc 2010 roof snow load nbc 2010 version 0 1 0 september 13 2020. Length of roof upwind of the snow drift.

Using the recent data on the groundload to roof load conversion factor statistics are obtained for the one year and fifty year snow load. Rain load s r. If unbalanced snow loading isn t required or specified the truss designer may enter the 25 psf snow load as a top chord live load tcll set the load duration factor to 1 15 for snow and turn snow loading off completely. Length of roof downwind of the snow drift.

Horizontal distance from eave to ridge. Based on these statistics the reliability index is on the order of 1 6 when snow load controls the design. The ansi snow load subcommittee took advantage of this new information to update and improve calculation of roof snow loads.