Horizontal Shear reinforcing in Walls
Horizontal Shear reinforcing in Walls
(OP)
Folks,
Are you required to develop the horizontal shear reinforcing bars at each end of the wall or is it sufficient for the bars to be straight without hooks or closure U bars.
Are you required to develop the horizontal shear reinforcing bars at each end of the wall or is it sufficient for the bars to be straight without hooks or closure U bars.






RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
I don't know how you can possibly know whether slickdeals needs shear reinforcing in his walls, or how much, without knowing anything about his building. Shear walls in buildings often do require shear reinforcing. I don't find his question unusual at all.
RE: Horizontal Shear reinforcing in Walls
I don't know either, so that's why I suggested to double check analysis using FE to utilize two way action. Many times, it goes away, or might stick, but worth a try if he hasn't done so. We both know shear reinf is not desirable in wall unless there is no way out.
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
If it is kslee that you are asking to answer your question, I doubt that he understands the question. Otherwise, why would he say that SHEAR reinforcement in a SHEAR wall is not desirable? That's like saying that compression reinforcement in a column is not desirable.
For my answer to your original question, refer to my first post.
RE: Horizontal Shear reinforcing in Walls
What does "two way action" have to do with the design of shear walls?
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
I typically still apply the hook requirement to non-seismic walls with Vc over 1 sq-root.
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
In a wall, both horizontal and vertical bars will contribute to shear strength.
BA
RE: Horizontal Shear reinforcing in Walls
Does the U bar size need to be the same size as that of the horizontal shear reinforcing bar or is the U bar only a better detail? For example, can I use a #5 U bar lapped with a # 7 bar about 24"?
RE: Horizontal Shear reinforcing in Walls
BA
RE: Horizontal Shear reinforcing in Walls
Are you designing facility for nuclear power plant? How thick is the wall, how you bend #7 into U, have you check the bendind radius, does the required bond can develop, would the enclosed concrete crash before the yield of steel??????
RE: Horizontal Shear reinforcing in Walls
Mike McCann
MMC Engineering
RE: Horizontal Shear reinforcing in Walls
BA
RE: Horizontal Shear reinforcing in Walls
In a wall where you need #7 bars as the shear stirrups, I would not skimp on the anchorage. Shear walls are just cantilevered deep beams, and you wouldn't change the size for beam stirrups. Anchorage of shear reinforcement is critical. As to #7 bars being hard to bend, I don't think so. If there is not enough room to accommodate the bend, your wall is not thick enough. I imagine this shear wall is in a high rise building, so low rise thinking has no place.
RE: Horizontal Shear reinforcing in Walls
I don't think that I understand your question. If you have a shearwall it can have two kinds of reinforcing:
1. The vertical flexural rebar, that is located on both ends of the shearwall.
2. The horizontal and vertical closed stirrups that are required when the shear is greater than phi times Vc/2. These closed stirrups are sized and spaced as called for in chapter 11 of the ACI.
I don't see how the vertical or horizontal closed stirrups need "development".
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
Greetings
Tony
RE: Horizontal Shear reinforcing in Walls
What we are talking about, if I understand the thread correctly, is a shear parallel to the shear wall under consideration. It arises from wind pressure acting on faces of the building normal to the shear wall. It does not act on the face of the wall in question. It is transferred through diaphragm action of the floors and roof to the shear wall whose reinforcement we are discussing.
BA
RE: Horizontal Shear reinforcing in Walls
The wind load is normal to a 24" thick wall which is about 26' long. The building is a stadium and I can't divulge more details. We are assuming certain portions of the building not contributing to the lateral system to build in a conservatism in design.
RE: Horizontal Shear reinforcing in Walls
That is a completely different situation from the question posed in your OP. You talked about horizontal bars, which won't contribute to the shear resistance normal to the wall.
RE: Horizontal Shear reinforcing in Walls
That's the reason I was urging you to perform a plate model. It is suspecious that you have such high shear under the condition stated. I think the #7 is for flexural bending, not for shear. If this is correct, the development #7 is up to the location that requires it (ends, or middle). But no matter what, for 24" thick wall without column at wall ends, I would provide U bars to better protect the end faces. However, I would try to use smaller bars, such as #5, to reduce the unprotect space in between wall corners and the bar bents.
RE: Horizontal Shear reinforcing in Walls
Maybe I still don't understand the problem. Perhaps a sketch would be helpful.
BA
RE: Horizontal Shear reinforcing in Walls
RE: Horizontal Shear reinforcing in Walls
Tony.
RE: Horizontal Shear reinforcing in Walls
Suggest to review ACI 11.10 (shear wall). Read commentary carefully, and try to understand it. You may need to get to other texts to have full grab on what it was talking about.
Please keep in mind, unlike typical cantilever beam, you have relatively high gravity load compared to the lateral load (due to wind), which would help alleviate the in plane shear stress. Double check your design with methods suggested.
RE: Horizontal Shear reinforcing in Walls