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Ce 479 Fall 05

Steel Roof Deck

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Steel Roof Decks• Support the built up roof carrying the weight of

the insulation, roofing material and the roof live and/or snow loads plus construction loads

• Steel decks are formed from sheet metal into fluted units. They are commonly 1.5” deep but deeper units are also available (Vulcraft Catalog pp. 3-8)

• Specifications and commentaries (Vulcraft pp. 9-16)

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Steel Roof Decks

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Steel Roof Decks

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Steel Roof Decks• The Steel Deck Institute (SDI- Vulc. pp. 9-16) identifies the profile as IR

(intermediate rib pg. 10). A comparison of weights for each profile in various gages shows that weight/strength is most favorable for wide rib decks. Selection resulting in the least weight/ft2 is most appropriate.

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Steel Roof Decks• Consideration must be given to flute width because the

insulation used must span the flute. In the north US thick insulation and high roof loads make the wide rib profile WR (B-manufacturers) more common.

• In the southern US climates, lower roof loads and thinner insulation make the IR (F) more common.

• Where very thin insulation is used, NR (A) may be required.

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Steel Roof Decks

• Allowable Stress Design (ASD) Service Loads:

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Steel Roof Decks

• Construction Loads: Note 20 x 1.33 ~ 26.6 ksi

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Steel Roof Decks

• Limit Deflections:

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Steel Roof Decks– Design Example: 1.5F20 on a 7 ft simple span. Check the

controlling condition for the allowable load shown of 38 psf.