1950s Lightweight Concrete Compressive Strength

[sawoods]

I am currently using original construction drawings from 1959 to determine whether or not a roof stucture can support new imposed loading. The drawings show a " 2" lightweight pre-cast concrete plank" roof deck. This is the only information the drawings contain concerning the roof deck. What strengths were they making back then that I could used for an assumed value of f'c for the concrete?

 

[BAretired]

Try 2000 psi. It likely was more than that.

BA

 

[msquared48]

2"? The supporting members must be at 3 to 4' spacing then?

2000 psi is a reasonable assumption without using special concrete testing equipment.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[dik]

I've seen similar... max span approx 2'-6"... and f'c=3000 psi...

Dik

 

[sawoods]

The supporting beams are at 6'-6" O.C. The concrete planks are only about 12" wide. One spot of spalling reveals some pretty heavy duty W.W.R., but otherwise, they seem to be in good shape. It seems like a pretty questionable system, but it's worked for over 50 years, with a ballasted roof until just recently, so it can't be all bad.

Thanks for the help.

 

[msquared48]

Must not see any appreciable snow loads.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com