Historic rebar identification 1

[Catacus]

I have a concrete slab that is reinforced with what appears to be 3 wires twisted together, about 3/16" dia wire.

The slab is about 6" thick with the twisted bars bottom at 6" on center spanning 9 feet between dropped concrete beams. It was a 4 story warehouse buildng, not sure of the age but obviously old, and it's in the midwest.

Any info on this type of reinforcing would be appreciated.

 

[MiketheEngineer]

Years a go they used just about anything for rebar as there were no "standards" - they just knew it helped. Scrap steel in bars, pipe or even angles was often used.

You might try to figure some kind of cross sectional area and then run some designs - just be very conservative.

 

[Catacus]

Thanks Mike, I'm sure that you are right about that. It is a substantial building though so they must have obtained a lot of it. I googled it and looked through the old reference books and didn't see anything like it so I thought I'd check here. As you imply it's just a matter of getting the area of the reinforcing and doing some checks. Thanks again

 

[SlideRuleEra]

Catacus - If the building is really old, say early 20th century, you may have one of the patented reinforcement systems from that time period. See the attached document for guidance on evaluation of this type of reinforced concrete.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[Catacus]

That's great, I'll see what I find, thanks Sliderulera