shear friction footing no dowel
shear friction footing no dowel
(OP)
can someone guide how to calculate the shear friction in this case
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shear friction footing no dowel
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RE: shear friction footing no dowel
RE: shear friction footing no dowel
If you don't, you can epoxy rebar from the top section of the footing down into the bottom section.
From a practical standpoint, can you make the footing work with the (bottom) section that is remaining? The top bar does nothing for you for a single downward load.
RE: shear friction footing no dowel
what should I be checking at in this case to make sure this is ok.
actually the original picture is wrong. it's a square footing with 4 sonotube piles.
RE: shear friction footing no dowel
RE: shear friction footing no dowel
Here though, I'm not sure this is allowable: you've got no friction steel (forgetting about the sonotube re-bar that crosses the crack). And a pile cap doesn't qualify as a plain reinforced concrete structure in my book.
I would advise you to use some re-bars (Hilti into the first pour and hooked into the second) to make this happen.
RE: shear friction footing no dowel
I just can't picture the concrete sliding horizontally due to vertical force?
RE: shear friction footing no dowel
RE: shear friction footing no dowel
And I can't picture a perfectly vertical force either. (No horizontal from a lateral event on top of that?) So to be on the safe side, I'd comply with code. I don't know what this is supporting.....but it's got lawsuit written all over it with this plan.
RE: shear friction footing no dowel
RE: shear friction footing no dowel
Maybe. But watch out for that: ACI code (at least the latest one I use) still requires you to fully develop the shear re-bar on both sides of the interface. With the Hilti you will have it on one side......but tougher to get that (i.e. full development) on the other side.
RE: shear friction footing no dowel
Sounds like some demolition is needed or some external strengthening to provide a connection. And it should extend to the bottom of the footing/slab.
RE: shear friction footing no dowel
it's supporting a pipe.
RE: shear friction footing no dowel
Hilti has a new rebar design guide where they give equations for shear friction capacity for adhesive dowels where you don't have full development.
If you can't adequately transfer the vertical loads and their corresponding shear flow then essentially the lower portion of the footing will do all the work. This means you will have an increased weight (the weight of the upper portion of the footing) and the lower portion will have a reduced 'd' which will lower your moment capacity.
RE: shear friction footing no dowel
RE: shear friction footing no dowel
1) Model the thing in your head as a four strut strut & tie system.
2) Rough out the forces in each of the four struts.
3) Check the horizontal joint across each strut using shear friction.
4) Consider the vertical component of each strut force to be a clamping force doing the job that shear friction reinforcement normally would.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: shear friction footing no dowel