Metal Grating Material Yield Stress

[Lemony]

I am a structural engineer in the states. I am looking at some metal bar grating for a factory floor. This is carbon steel stuff and its vintage is 60's. The Metal Bar Grating Manual (MBG 531-09 published by NAAMM) uses an allowable stress of 18 ksi. I Believe that I can eek out extra capacity by using AISC Specification for Structural Steel Buildings, 13th Ed, Section F11.

Does anyone have a reference for what the yield stress of this vintage of metal grating is? I am currently using 33 ksi, but I suspect the NAAMM manual uses 36 ksi (and so a safety factor of 2).

Thanks.

 

[JedClampett]

Why don't you have it tested? It will give you a 100% confident number and you'll probably get an even higher number than 36 ksi.
Note that the 18 ksi used is probably a way to restrict deflection.

 

[JLNJ]

My old Klemp book has astm A569 as the material with fb = 18000 psi. They also reference an allowable of 20000 for A36.

Even if you just took advantage of the plastic section and kept it to 18000 you will get a decent capacity increase over using the elastic section modulus.

 

[Lemony]

Thanks for the input Jed and JLNJ.

Deflection is addressed separately.

JLNJ, so does that mean a SF of 1.8?