Concrete shear wall boundary elements
Concrete shear wall boundary elements
(OP)
Are you permitted to have just a single layer of reinforcing at the boundary elements. The code requires confinement steel if compression exists. So providing confinement is really not possible with just 1 layer of reinforcing. I believe you must always have 2 layers with confinement ties. Does anyone know if a single layer can be detailed?






RE: Concrete shear wall boundary elements
You don't always require confinement at your boundary elements. If you don't need it the sure, one layer. But if you do need confining then I agree, you'll need two layers (at the boundary element at least).
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Concrete shear wall boundary elements
If it is ordinary concrete shear walls, one layer can certainly be used. I use the horizontal bars with a 180 degree hook around the boundary steel for confinement.
RE: Concrete shear wall boundary elements
Clever. I'd never thought of it this way. Does that mean that you limit your boundary steel to single vertical bars? Or maybe a bundled group of two or three?
I'm not sure how much of a code issue it would be but, with the confining steel being placed in the middle of the wall, I'd be comfortable with 90 degree hooks. And that means that I could just use standard corner bars lapped with the horizontals. Contractors would love that...
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Concrete shear wall boundary elements
RE: Concrete shear wall boundary elements
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Concrete shear wall boundary elements
RE: Concrete shear wall boundary elements
The question that I have here is the extent to which this arrangement constitutes confinement in the direction perpendicular to the wall. Normally, you're tying a bar on one face of a wall to another bar on the opposite face, engaging most of the wall thickness. Here that's a bit more questionable. Both bars might just buckle laterally together which would make tying one against the other pointless.
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Concrete shear wall boundary elements
RE: Concrete shear wall boundary elements
What types of software do either of you use to analyze shear walls? We just started using RAM Elements and RAM Concrete and trying to figure this all out.
Thanks.
RE: Concrete shear wall boundary elements
I try not to take this stuff too seriously. In the US, you calculate your limiting compressive stress for confinement based on the uncracked concrete section. And that means that it's completely wrong and really nothing more than an index.
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Concrete shear wall boundary elements
That being said, I've used ETABS, RAM, and RISA to do shear walls. For ordinary shear walls in fairly regular buildings, RAM is awesome and easy to use. For special concrete shear walls or shear walls in irregular buildings, you may want to consider ETABS. RISA seems to handle both ordinary and special shear walls fairly decently.
RE: Concrete shear wall boundary elements