Diamond Plate Diaphragm

[RWW0002]

Has anyone ever come across any information on the use of steel raised-pattern floor plates as diaphragms? I am considering using 1/4" floor plate welded to mezzanine framing as a diaphragm for mezzanine seismic resistance.

Thanks,

 

[KootK]

I don't know of a table of code approved diaphragm values or anything like that. Intuitively, one would think that this would work rather well so long as your fastening scheme is permanent and capable. It might be something of a no man's land with regard to design guidance. For diaphragms of cold formed steel, we use published values. For diaphragms of discrete horizontal bracing we do our own engineering. Where does thick steel plate land on that continuum? I'd wager closer discrete horizontal bracing. While not perfectly applicable, you could look to design guides for steel plate shear walls for some aspects of design. For typical support member spacings, I imagine that it would just come down to shear buckling.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[jayrod12]

I would bet this is a demand type thing first. I.E. what do you need out of the diaphragm? If you can get 1kn/m of shear resistance out of drywall then you must be able to get that or more from checker plate.

I've made this rationalization for using steel grating. I specified that it had to be welded to the support structure instead of clipped. All has been good so far.

 

[RWW0002]

Thanks. My thought s are in line with the above. Connections and shear bucking will likely control, and there is a certain amount of intuitive resistance to the system. I have a feeling that my demand will be low enough that the diaphragm capacity can be justified without much rigor, I was just looking for an easy out if available.

The only part I am not a big fan of is all of the overhead welding of continuous sheets.

 

[jayrod12]

what about providing holes through the diamond plate and welding from the top?

 

[EngineeringEric]

AISI and SDI have diap. capacity for heavy gauge metals... if you are thicker than you have those values at a minimum, assuming equal capacity per fastener.

 

[RWW0002]

Yes plug welds from above are an option.

As far as AISI and SDI values, I do not have it in front of me but I have only seen values for closely spaced support members (16" or 24") While I can not span much farther than that with the metal plate, my support spacing will exceed these values. I agree with you that that data and methodology may be the most directly applicable though.

Thanks All.