Strength of Existing Metal Roof Deck

[KYStructuralEIT]

As part of a project to support a 4,000+ lb mechanical unit on an existing building, I will need to check the metal roof deck.

The unit sits on 1 1/2" curbs that will be attached to the existing wide-rib 1 1/2" x 20GA metal deck. In turn, the curb load will be supported by new beams.

My question is: how can I check that the metal deck won't crush under the curb loading running perpendicular to the flutes (275 lb/ft in this case)?

I am a recent graduate looking to gain experience from this group.

 

[hokie66]

Ron, I thought the 1.5" was the width of the curb, but maybe not. Certainly needs to be higher than that.