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Properties of Historic Steel Shapes

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StructEngineer11

Structural
Apr 4, 2016
11
I am working on a repair of an old structure, and had a question about the properties of older steel shapes. The existing structure I am working with was designed in 1953. In checking the capacity of one particular W10x33 beam, I have used the AISC 5th edition manual (which was copyrighted in 1947). In it, it references the usage of ASTM A7-46, which is actually included in the manual. I then flipped to that spec to find that the yield strength was 33 ksi for that particular grade. However, in doing some other calculations, I need to use the elastic modulus (E) and the shear modulus (G), which that spec does not provide. Does anyone know what was typically used for those values back then, or where I could find that? Is it safe to just assume those are still 29,000 ksi and 11,200 ksi, respectfully?

Side note: The ASTM A7-46 spec does provide values for "elongation in 8 in., min., per cent" of 1,500,000/(tens. str.) and "elongation in 2 in., min., per cent" of 22. (See attached.) I realize those may be strain values, and elastic modulus is stress/strain, but I'm not getting a number in the ballpark of 29,000 when taking that approach.
 
 http://files.engineering.com/getfile.aspx?folder=e3efbe2a-11a0-426e-9684-9f4f73299c15&file=IMG_1468.JPG
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Look on page 346 of your fifth edition AISC manual for values of E.

E generally is always 29,000 for most steel materials. G will always follow the equation G = E / (2(1+poissons))



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I believe the elongation in 8" includes extensive plastic deformation/ necking down and wouldn't give you the modulus of elasticity if divided out, except possibly for a very brittle material. Also, the values in a specification would be the minimum elongation, not the average.

My 5th Edition, 1948 of AISC has a table of E over in the back, and all the different grades of steel are shown as 29,00,000 psi.
 
Thanks for the responses. I see the E values on page 346 now, so I think it's safe to use 29,000. I was aware of the formula for shear modulus, but didn't know for sure if Poisson's ratio was still the same. I'll assume it is.
 
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