Prestressed Piles - Historical Information

[humanengr]

I'm checking some old pre-stressed concrete piles constructed in the mid-1970's. There are no specs. available for the piles. Currently pre-stressed piles typically have 4,000 or 5,000 psi concrete. Does anyone know if it was "standard" to use 4,000 psi concrete back in the 1970's. Is there any reason to believe they may have used less than 4,000 psi?
Thank you.

 

[SlideRuleEra]

In the 1970's prestressed concrete strength would have been at least 4000 psi, probably higher.

I do have a 1961 AASHO (as AASHTO was named until 1973) committee recommendation that prestressed concrete strength be in the 5000 psi to 6000 psi range. Here is a scan of that portion of the 1961 document:

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net