Point Load on Metal deck w/ concrete

[joengineering]

Hello all,

So I have a point load on a metal deck with concerete. I will definately check punching shear but I wanted to check if bending was ok. I have attached a calculation showing what I did to find the bending capacity. Let me know if you think this makes sense, I used a 12" strip. Also, if yoy guys have other methods that would help to.

JO

 

[Once20036]

Canam has a number of design examples on their website - including some for concentrated loads.
I've saved the printouts so I don't have the website, but it should be quick to find. I'd follow their procedure.

 

[steellion]

You can use the allowable PSF loads from the deck catalog to back-calculate moment and shear capacity of the deck span. Then compare the moment and shear capacity to the demand from the concentrated load.

 

[CANPRO]

I belieive this link may give you the design example referenced by Once20036. You may want to double check your effective width.

http://www.canam-steeljoists.ws/

http://www/v4/ecanams.nsf/steeljoists/design_tools?open

 

[joengineering]

ONCE20036/CANPRO,

In CANAM phiMno is given in their steel deck catalog. I am using VERCO, if I dig around I can probably find something near what I am using in CANPRO I guess.

Steellion,

I like that idea.

JO

 

[jayrod12]

The only thing steelion's method doesn't take into account is localized web crippling.

 

[joengineering]

jayrod12,

I think if I check only the 3 1/4" for punching shear, that will eliminate any possibility of web crippling on the deck?

JO

 

[jayrod12]

Probably, and I also forgot you mentioned there is concrete which significantly reduces the chance of any web crippling

 

[joengineering]

I actually compared what moment capacity Canam gives you with my calc and it is really close

 

[SEARUN]

I just worked on something similar. In its catalog Verco recommends checking the moment and shear capacity based on the allowable uniform loads. Calculate capacities based on a simple span beam (they assume concrete will crack over supports since it is in tension). Note that the moment capacity and shear capacity are flat lines (eg wl^2/8 is the moment capacity anywhere along the span and wl/2 is the shear capacity anywhere along the span)

 

[joengineering]

SEARUN,

Where in the VERCO catalog do they recommend that? I would like to see it for reference.

JO

 

[bigmig]

Someone gave this to me years ago. It helped me with this same question. See attached.

 

[SEARUN]

Joe,

See page 7 in the Verco Steel Floor Deck. I talked with the Verco engineer about the capacity (flat line). Makes sense- similar to wide flange beam you have the same moment capacity and shear capacity any point along the beam assuming everything is laterally braced, etc.