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Yield strength of older rebar

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ASTM A 305 is the specification for deformations on reinforcing, not yield 
strength.  Before ASTM A 615, the specification for rebar consisted of two 
requirements:  generally ASTM A 15 for strength and property requirements 
(structural, intermediate or hard grade) which was for plain *or* deformed 
bars, and ASTM A 305, which was for deformations.

ASTM A 15-54T (Tentative) requirements for deformed bars are as follows:

Structural Grade:
      Tensile Strength:    55 - 75 ksi
      Yield point (min):   33 ksi
      Elongation:          1,200,000/(tens. str) but >= 16%

Intermediate Grade:
      Tensile Strength:    70 -90 ksi
      Yield point (min):   40 ksi
      Elongation:          1,100,000/(tens. str) but >= 12%

Hard Grade:
      Tensile Strength:    80 ksi (min.)
      Yield point (min)    50 ksi
      Elongation:          1,000,000/(tens. str)

Elongation is in 8" gage length and is minimum.

ASTM A 15 was issued in 1950, revised in 1952, and June and October, 1954.  
Prior to being published as a "Tentative," the specifications were issued as 
a standard from 1911-1950, being revised in 1912, 1913, 1914, 1930, 1933, 
1935, 1939, and 1950.

Hope this helps.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Scott Maxwell wrote:

>>Is anyone familiar with ASTM 305 for reinforcing steel?  I am looking at a
building built around 1957 that specifies ASTM 305 for the rebar.  Would
this have a yield strength of 40 ksi, or something else?<<