1980's Rebar Strength

[Den32]

Hi, checking an existing single-story concrete roof structure built between 1981-1983 in eastern Virginia, USA.

I know that both Grade 40 and Grade 60 rebar was available during that time period.

Does anyone know if Grade 60 was the 'standard' during that time? We don't know the rebar or concrete properties, so we need to make reasonable assumptions.

Will assume 3000 psi for the concrete which is probably conservative.

Thank you.

 

[ztengguy]

reasonable would be grade 40, without testing. Are they prestressed perhaps too? Whats the span, is it just a slab?

 

[Den32]

One-way slab spanning to beams. Single-story roof structure. No, mild reinforcing. We have the record drawings, but only the Plans & Section Sheets.

The Plan sheets refer to the "General Note Sheets" for design loads and strength properties, but we do not have those particular sheets.

 

[hokie66]

I practiced in Richmond from 1970 to 1982. For 1981-1983, the standard was Grade 60 for everything except ties and stirrups, which were Grade 40. But Grade 40 was still available in larger sizes...I think.

 

[DST148]

@Den32 - Try thread507-212150. It provides a link to CRSI Engg. Data Report 48 which lists specs for rebars from 1911 to present.

 

[UcfSE]

CRSI EDR 48

 

[MiketheEngineer]

Unless it is critical - just use Grade 40. If that doesn't work - you might try to get a coupon test...

 

[JAE]

My experience in all the 1980's was what hokie66 stated....60 grade for most bars and 40 grade for #3 stirrups and ties. Many times grade 40 for #4 stirrups and ties.

 

[Den32]

Thanks to all for the input. Very much appreciated.

Go GIANTS!