Lateral load system for a gable roof building

[structural7722]

I am designing a cmu building with a gable standing seam over steel decking roof. I am unsure if I can count on diaphragm action from the roofing to serve as the lateral load transfering mechanism into shear walls or if I must design a horizontal roof bracing system instead.

 

[OHIOMatt]

A little more information would be helpful.

What type of metal deck are you planning to use?
What is the direction of span for the metal deck?
Is the metal deck being deisgned as a diapragm with sufficent connections to the shear walls?
What are the load parameters for the project, such as wind speed and seismic design category?

 

[MikeE55]

I'm assuming you know the standing seam contributes zero and you are asking whether the structural deck being on a slope prevents you from using it as a diaphragm. The short answer is if it is connected properly it can work as a diaphragm, but loads are increased due to the slope. i.e., it is not as efficient as if the diaphragm is horizontal.

 

[msquared48]

If the steel deck is 22 gage or thicker, you should be able to use it as a structural diaphragm. Definitely not the standing seam stuff though.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[msquared48]

I'm also assuming a minimum of 1.5" deep decking, not formdeck.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[MiketheEngineer]

Agree w/ above and most mfgs can give you values