Ties for wall vertical reinforcement 9

[WARose]

I have a feeling what the answer is on this one......but I'll ask anyway ()......Does anyone know of anyway (via a code anywhere) that allows you to consider a single layer/curtain of vertical wall reinforcement as "tied' via the horizontal steel? The way I've always read ACI code.....you need to have 2 layers/curtains of vertical steel, with ties between them in order to call it tied as per code.

Basically what I have is: a wall with a single layer of vertical reinforcement (and a horizontal layer as well). I'd like to use that steel as compression steel (for a vertical load on the wall).....but it's not tied. It's a pretty short wall (4' high, 10" thick).

 

[JAE]

Yes - I see it. Seems like that's been now relegated to only columns and pilasters (vs. walls) in later editions while the 05 edition simply refers to compression in masonry.

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[Guest090822]

Did the OP’s question ever get answered?

 

[JAE]

Well, sort of. I guess WARose should respond on that, though.



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[TLHS]

Koot,

That load reversal style of failure is one of the banes of concrete construction in seismic design. You get load reversal failure, then you cycle a few times and the concrete disintegrates. Then you lose the compression or shear load path because you just have a bunch of bars hanging in the air and bad things happen. This is why tie and stirrup detailing are a big deal in concrete seismic systems.

 

[WARose]

I consider it answered. I actually had forgotten about that section of ACI that the debate broke out about.

That reference i posted above (from the NZ code) appears in other forms in other references I have (in a more usable form).....when I get a chance, I'm going to mess around a bit and see what sort of concrete strains correspond to minimum tie areas (as per ACI 318 vs. NZ code).

EDIT: And by the way, thanks to everyone who participated.

 

[KootK]

@TLHS: agreed. I was pretty careful to exclude seismic in all of my comments. That's actually something that I've come to resent a bit. Nowadays, I feel as though I'm obligated to preface every damn thing that comes of my mouth with "..unless it's seismic..."

 

[TLHS]

Koot, wasn't really disagreeing or pointing out a problem. Just expanding on your hinge zone caveat.

 

[MrHershey]

Resurrecting this thread to close loop on the errata and code updates referenced by JAE above. Looks like things have formally changed here.

Previous language in ACI 318-14:

Language from ACI 318-14 errata:

Current language in ACI 318-19:

 

[JAE]

whew. All is right with the world. I can calm down now!

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