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Re: 1937 VA job- rebar and concrete strength

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Andrew, Roger,
        You might consider testing a few concrete cores and a few steel bar specimens.
        We did this a year-an- a-half ago.  In our case we found concrete strengths around 3,500 psi (less than I expected for 94 year old concrete) and one steel test at 38,000 psi plus five at 42,000 psi (higher than I expected for the steel).  I don't remember the exact cost but it was only about $600 for the two (certainly less than a thousand).
H. Daryl Richardson
----- Original Message -----
Sent: Friday, June 06, 2008 9:42 AM
Subject: Re: 1937 VA job- rebar and concrete strength

Contact CRSI at They used to provide free downloads of their technical data sheets but I couldn't find them this morning. I found the following in their FAQ section:
"In the late 1970s, when staff began experiencing a large number of inquiries regarding old reinforcing bars, CRSI published Engineering Data Report 48, "Evaluation of Reinforcing Bars in Old Reinforced Concrete Structures."
Table 5 in that publication provides minimum yield strengths for all reinforcing steel bars produced since 1911 correlated to ASTM specification grades. For more information, see EDR 48 and CRSI's handbook, "Evaluation of Reinforcing Steel Systems in Old Structures.""
Roger Davis
Architect, Retired

"Andrew Kester, P.E." <akester(--nospam--at)> wrote:
I am doing a job in a VA hospital in VT built in 1937. This is the second time I am doing a job there, did one 6 years ago with my old company. They gave me some of their files from when I worked on it the first time. I used f'c=2500psi concrete strength and fy=33000psi rebar strength the first go-round. They have a more involved peer reviewer, a PE, who wants some justification. I am searching on my own right now, I want to guess Nels or Harold or somebody sent me a PDF or something they had in their libary for the rebar values...
Andrew Kester, P.E.
Principal/Project Manager
ADK Structural Engineering, PLLC
1510 E. Colonial Ave., Suite 301
Orlando, FL 32803

Roger Davis
SDS Architects, Inc.