Metal Roof Deck in Compression

[nr123]

Has anyone ever considered metal deck in compression. I am looking at section 1620.3.1 (IBC 03) which deals with anchorage to concrete or masonry walls. Would like to justify that in the strong direction of 1 1/2" metal roof deck that the loading imposed by Eq. 16-62 could be taken in compression thru the decking and be transferred into the joist girders which would act as the ties between the masonry walls. In the opposite direction, the metal deck is braced by joists at 6'-0" max, therefore the joists top chord would be designed for a small tension/compression loading.

Any help would be greatly appreciated.

Thanks in advance.

 

[jike]

You should be able to calculate a slenderness ratio of the deck. I have also seen some engineers put a smaller joist space at the end or add additional bracing members to the first joist to carry this compression.

 

[jike]

I also remember seeing a drawing which specified an extra layer of deck over the first layer to carry the compression. There are many ways to skin the cat!

 

[nr123]

I have used steel angles between the joists spaced accordingly to almost create something of a "sub-diaphragm" however when the seismic loads are relatively small it would be nice to rely on the metal deck to do the work for you instead of adding additional steel.

 

[msquared48]

I don't know that I would rely on the deck for compression from seismic/wind forces.

Seems to me the angle on which the deck bears should be designed to be strong enough to span out any lateral loads to the open web trusses and, eventually the steel deck diaphragm.

Mike McCann
McCann Engineering