Frangible Concrete Reinforcing

[timbercharlie]

I have recently come across a specification for "frangible" rebar in a concrete footing. Does anyone have any info on "frangible" reinforcement? I have googled it and called a couple suppliers and can't find any explanation.

Thanks!

 

[cntw1953]

Can you type the whole phrase, or notes. May it be a typo?

 

[ishvaaag]

fragile, breakable (Webster's)
readily or easily broken (Longman's)

Normally we are looking for ductile steels for reinforced concrete. Fragile the concrete is. Then, the high strength steels attain lower elongation over "yield" point. It is more than enough, anyway, to make noticeable any cracking that not progresses thunderously to failure. And frangible steels (as some cast irons and old irons are) are routinely specified for vertical signing posts, where it is preferred the sign be ejected by the impact than hammering the vehicle in whipping action.

So ... except that someone has wanted to signal that the steel standing in the footings is not ductile, it would be a funny note, because most would put such class of steel or HS steel directly, instead.

 

[BAretired]

I don't know why anyone would manufacture "frangible reinforcement".

http://www.google.ca/search?q=frangible&hl=en&sourceid=gd&rlz=1Q1IRFA_enCA356CA356&aq=t

BA

 

[cntw1953]

One word a day

 

[timbercharlie]

It doesn't make since to me why an engineer would specify "frangible" reinforcement either. The project I'm referring to is on the coast of Florida and subject to wave action during a hurricane... after reviewing this more, I'm thinking the lower floor at or below the wave crests is actually sacrificial or breakaway so as to remove surfaces that the wave action could impact(?), thus preserving the balance of the structure. I called a couple rebar suppliers and they have never heard of "frangible" reinforcement.

 

[concretemasonry]

It sounds like you are facing "blow-out" walls to reduce the resistance of the storm surge. I have seem many along the Gulf coast (MS, AL) where they use rectangular reinforced structural block columns (long axis perpendicular to shore) and then run in-fill sacrificial unreinforced block walls between the structural piers. The lower level can be finished and useble, keeping in mind it will eventually be flooded or the sacrificial walls blown out (ala Katrina). - Good for garage, storage, utilities, rec room or TV theater. Just remove the valuables.

I don't know about the terms or possible miss-spelling, but could be the intent. You don't want the blow-out walls to be too strong even though we engineers usually like the "belt and suspenders" philosophy to provide redundancy.

Dick

 

[dhengr]

Call the people who wrote the spec. and did the plans, and ask what frangible conc. reinf. is, and what the terminology means in your case. No need to feel embarrassed. Tell them that you have asked ten of your very best friends, who just happen to be great structural engineers also, and they didn’t know that terminology either.

 

[cntw1953]

6, you and I included, need 4 more curious cats to make the claim

 

[dhengr]

cntw1953:

Seems we have crossed paths before, generally in an agreeable fashion. But, the idea that you expect I should be able to count too, is pushin it a bit too far, you are gettin downright disagreeable. We are gettin closer, 7 now, I was anticipating 10 before timbercharlie looked again.

 

[Ron]

Frangible walls, yes...as CM described..a blow-out wall. Frangible reinforcement?? No. Maybe he/she is describing that as a level of reinforcement to achieve a frangible wall.

 

[concretemasonry]

If it is "frangible" it is not in the normal dictionary, but could be from a different language background.

The loose spec is probably too vague and unenforceable without any further definition or request for clarification.

Dick

 

[hokie66]

Frangible is a perfectly good word to describe brittle things like potato chips, but I can't see how it applies to reinforcing steel.

 

[msquared48]

He/she probably meant "fragmentable" concrete reinforcing.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[beton1]

Got ten yet? Lost count.

 

[kelowna]

For all what is worth, count me in on those 10.

Not only I have no idea about what it could mean, I am extremely curious now about what it is!