Yield Stress for Old Reinforcing Bars 2

[Kman57]

I'm evaluating some concrete beams that were designed in 1926. Any idea what the yield stress for reinforcing bars from that era is?

 

[jike]

Without any additional info. or rebar tests, I would not recommend using a yield greater than 33 ksi.

I suggest that you order a copy of "Evaluation of Reinforcing Bars in Old Reinforced Concrete Structures", Engineering Data Report Number 48 by CRSI.

Grades:
structural 33,000 psi
intermediate 40,000 psi
hard 50,000 psi

 

[Ussuri]

My 1937 copy of Trautwines Civil Engineers Reference Book gives:

"Normal reinforcing steel ultimate strength of between 50,000 - 70,000 lbs per sq in with elastic limit (yield) at 25,000 - 35,000 lbs per sq in.

Cold working the bars will raise the elastic limit to 40,000 - 50,000 lbs per sq in.

Deformed bars have a higher elastic limit claimed at 50,000 - 65,000 lbs per sq in."

 

[ahunt]

I pulled this information off the internet some time ago. It actually came from a post on eng-tips.

Hope it helps.





Per FEMA 356 Table 6-1, rebar typically came in 3 grades prior to 1968:

Structural: Fy = 33 ksi, Fu = 55 ksi
Intermediate: Fy = 40 ksi, Fu = 70 ksi
Hard: Fy = 50 ksi, Fu = 80 ksi





The following info is per CRSI Engineering Data Report No. 48:

Hard Grade is referred to reinforcing with Fy = 50,000 psi. and Fu = 80,000 psi.

Intermediate Grade is referred to reinforcing with Fy = 40,000 psi and Fu = 70,000 psi.

Structural Grade is referred to reinforcing with Fy = 33,000 psi and Fu = 55,000 psi.

These are tied into the following ASTM's:

1911-1966 - ASTM A15 (billet steel) (all three grades)
1913-1966 - ASTM A16 (rail steel) (Hard Grade only)
1936-1964 - ASTM A160 (axle steel) (all three grades)

I think you can get this document from

http://www.crsi.org