Snow on a Deck

Coefficient 144 in the formula reflects a transition from square inches to square feet Snow on a Deck 

As it was described above, a deck should satisfy a building code requirement of the uniformly distributed load of 250 Ib/fF. (100 Ib/fF of the requirements itself, with a factor of safety of 2.5). In some snowy areas there is a more stringent requirement for a deck of the uniformly distributed load of 400 Ib/fC. Let us consider a joist support span rating for this latter case with an example of GeoDeck. 

Strength At ambient (74°F) flexural strength of GeoDeck is 2490 psi and flexural modulus is 323,000 psi. At— 20°F the figures are equal to 3530 and 564,000 psi, respectively (Tables 7.20 and 7.41). Because we consider a snow load, let us take a modest 32°F. Below this temperature GeoDeck is stronger and stiffer. A simple linear extrapolation (there is no reason to seriously doubt this assumption) shows that at 32°F flexural strength would be 2955 psi and flexural modulus 430,593 psi. 

An alternative two sets of data (Tables 7.18, 7.19 and 7.39, 7.40) give us flexural strength and modulus for GeoDeck at ambient temperature, at 10 and at -20°F. Linear extrapolation of these numbers (flex strength and modulus separately, of course) to 32°F gives us flexural strength values of 2430 and 2820 psi, and flexural modulus of 445,000 and 360,000 psi, respectively (from two separate sets of data). From Eq. (7.41) we get that the uniformly distributed load at failure is equal to 

Snow Load on a Heavy Duty GeoDeck Hollow Board (Width 8.10 in.. Depth 1.55 in.. Moment of Inertia 1.858 in. , and Support Span of 24 in.) Using the extrapolated to 32°F flexural strength values of 2955,2430 and 2820 psi (see above), one can obtain the ultimate uniformly distributed load at support span of 24 in. for the board equal to 1749 Ib/fF, 1438 Ib/fF, and 1669 Ib/fF, that is, 3.6-4.4 times higher than the required 400 Ib/fF potential snow load. 

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Snow load, 272- 274 Snow on a deck, 272 Softwood fiber, 86, 100 Soil Block test, 431 Soil-block cultures, 434 Solar radiant exposure, 615 Solar radiation (UV light), 531 Solid board, 2, 16, 36, 267, 280, 281, 288, 311 Soundwall, 252, 269, 281-286 Bending moment, 282... 

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