Wharf Duck 1

[ejvlv]

How to determine the psi of existing concrete piles over 40 yrs. ago, Because I'm going to design a RC- Precast slab and RC- beam.
job'

i'm virgilio villacorta bs civil engineering. i'll been work assupervisingengineer on horizontal and vertical project morethan 18 yrs.

 

[Qshake]

The psi may be determine via coring and testing the sample. Alternatively, if you know the design strength of the concrete at the original placement you can use a factor of 1.5 to determine the strength of the aged concrete. Otherwise you can be conservative and use 1.0.

 

[RDK]

There is a non destructive testing method that may be useful. Its called a Schmidt Hammer. (also called a Swiss hammer). This method of testing is based on the inertia of a ball inside the Schmidt hammer testing apparatus that is "bounced off" of the concrete.

Be careful using this as it only gives the strength near the surface. It is also very susceptible to user errors (not holding correctly, etc.)

The big advantage is that it gives strength readings in seconds. Take lots and use the average.

They can be found on the net. Use your favorite search engine.
Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com

 

[Ron]

I would not use the Schmidt hammer for this application. The strength readings provided by this method are highly variable and often incorrect. This concrete likely has some surface deterioration (carbonation, sulphate attack, etc.), which will make the readings even more suspect.

The Windsor Probe would be a bit better than the Schmidt hammer, but the definitive assessment should be done by coring as you need to know the integrity of the concrete as well as its strength.