Cantalevered Roof Deck

[jorgen1212]

Ive designed a 1.5 B roof deck with a 3' cantalever using a beff = 1 foot
Deck flutes are perpendicular to perimeter bm.
Fb 20 ksi
Using a 50 psf SL and a 20 psf DL
M = 70 x 3^2 /2 = .315 k'
Sreq. = .315 (12) / .6 x 20 = .315
Sp = 3.18 for B18 deck
Any comments ?

 

[slickdeals]

Your allowable stress = 0.6 Fy = 20 ksi, assuming a 33 ksi deck. You don't need the additional 0.6 factor when calculating Sreq. Your Sreq should be 0.19 in3/ft. Also, Sp for a 1.5B 18 gage deck is 0.315 in3/ft

 

[wannabeSE]

The SDI RD-2010, Standard for Steel Roof Decks recomnends using a 200 pound concentrated load at the end of the deck for construction and maintenance. The standard can be downloaded for free:

http://www.sdi.org/sdiansi.htm

 

[hokie66]

Sounds like too far to cantilever 1.5" deck. Deflection?