Metal Deck Shear Buckling

[slickdeals]

Folks,
I have never worked much with calculating the capacities of bare metal decks and have a question.

I was recently reviewing a report where the shear capacity of a CF46 Metal deck (

http://www.corusgroup.com/file_sour..._Units/International/Comflor Decking new.pdf)

was calculated to be 16.1 MPa (2.335 KSI). It was mentioned that "shear buckling" controlled the capacity.

Where can I find information regarding how to calculate the capacity for metal decks?

We are Virginia Tech
Go HOKIES

 

[WillisV]

SDI's Diaphragm Design Manual is the industry standard for these calculations and provides information regarding shear buckling - it can be ordered here:

http://www.sdi.org/manuals.htm

As mentioned in a previous post you can also use Hilti's Profis DS program to determine shear strength of metal decks (including output for panel buckling/shear buckling strength) that match the Diaphragm Design Manual. Download here:

http://www.us.hilti.com/holus/page/...DF12752201C91443.node4?lang=en&nodeId=-153448

 

[ishvaaag]

I attach a pdf of a Mathcad 2000 worksheet for the calculation of the strength of trapezoidal deck sections. Therein the formulas for web crippling and strength are extant. Since it is maybe 10 years that I did it and didn't annotate it, I don't remember the exact model code or book I was looking at when doing the sheet.

 

[ishvaaag]

It seems the attachment didn't work. Try again.

 

[ishvaaag]

And now a copy of the mathcad worksheet zipped.

 

[slickdeals]

@Willis,
Thanks for the info. Where can I get more information regarding the various failure modes?

I am having a hard time picturing the shear buckling failure. I presume that this is out-of-plane and not in-plane. Shear forces can be traveling parallel to the flute or perpendicular to the flute.

In a direction parallel to the flute, I can see the flutes acting as stiffened columns. How does shear buckling happen in a direction perpendicular to flutes?

Also, if I can figure the equations in the SDI manual for shear buckling (Eq 2.3-3), which gives me a PLF value, can I then use this value and divide by a cross-sectional area / foot and calculate an equivalent shear stress?

I need to compute this because one of the reviewers is calculating a stress value (16.1 MPa / 2.33 KSI) and then asking to provide diaphragm shear stresses (S12 in ETABS) to prove the metal deck works.

We are Virginia Tech
Go HOKIES