DaveVikingPE
Structural
What is it? Grade 60.
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Rebar Shear Strength 1
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Do you refer to dowel action?
Some texts of the 70's and before explicited dowel action contribution. Since I don't exactly remember, I assume it is not unlike to that of shear friction...you see how rare the concept when inside a stirrups and main rebar cage, and the many implications or guesses for any differentiated adscription of strength to this. Anyway I think to remember it takes part even is some of the standing formulations for shear strength in ACI...so the answer to your question would be embedded in just "Use the code"...but I think the derivation of what I refer to -such contribution- was explicit in the Nilson book on RC still being sold, and maybe in the Park@Paulay one.
Some texts of the 70's and before explicited dowel action contribution. Since I don't exactly remember, I assume it is not unlike to that of shear friction...you see how rare the concept when inside a stirrups and main rebar cage, and the many implications or guesses for any differentiated adscription of strength to this. Anyway I think to remember it takes part even is some of the standing formulations for shear strength in ACI...so the answer to your question would be embedded in just "Use the code"...but I think the derivation of what I refer to -such contribution- was explicit in the Nilson book on RC still being sold, and maybe in the Park@Paulay one.
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DaveVikingPE
Structural
Thanks, Ishvaag!
I've got a CMU building that's going to be partly demolished. The building is a one-storey, multi-bay garage, with three sides closed, oneside permanently open, very simple. Basically, we're cutting the building in half and putting in a new wall. My wall design calls for connecting a new wall to the rear wall and a column at the "front" of the garage. The new wall, which is a load-bearing shear wall - of course - will be attached to the front column (a 24 x 24 CMU solid column) utilizing wall ties dowelled into the front column, connected with a high-strength epoxy chemical adhesive anchor. The manufacturer's specs, which are quite detailed, give "good numbers" were I to use a 1/2" diameter threaded rod (SAE - whatever). I, however, would prefer to use #4 rebar, Grade 60, because I can bend it and hence get the appropriate lap with the new wall's bond beams, etc. Since grade 60 rebar has "better" properties than threaded rod, I *know* I will get more positive numbers than threaded rod (i.e., tensile and shear strengths). However, I was at a loss to find shear strengths and, in desperation, threw the question to the Eng-Tips crowd. I've decided, after some more research, that I can assume a shear strength for #4 Grade 60 of around 8,000 psi.
Your thoughts?
I've got a CMU building that's going to be partly demolished. The building is a one-storey, multi-bay garage, with three sides closed, oneside permanently open, very simple. Basically, we're cutting the building in half and putting in a new wall. My wall design calls for connecting a new wall to the rear wall and a column at the "front" of the garage. The new wall, which is a load-bearing shear wall - of course - will be attached to the front column (a 24 x 24 CMU solid column) utilizing wall ties dowelled into the front column, connected with a high-strength epoxy chemical adhesive anchor. The manufacturer's specs, which are quite detailed, give "good numbers" were I to use a 1/2" diameter threaded rod (SAE - whatever). I, however, would prefer to use #4 rebar, Grade 60, because I can bend it and hence get the appropriate lap with the new wall's bond beams, etc. Since grade 60 rebar has "better" properties than threaded rod, I *know* I will get more positive numbers than threaded rod (i.e., tensile and shear strengths). However, I was at a loss to find shear strengths and, in desperation, threw the question to the Eng-Tips crowd. I've decided, after some more research, that I can assume a shear strength for #4 Grade 60 of around 8,000 psi.
Your thoughts?
Of course, how not, it is steel, and far more as well if on the steel part we are thinking only, but the question is however that what you have is an anchor to masonry.
Were it an anchor to concrete, the procedures in ACI clearly would define the capacity for ordinary cases, shear or shear plus tension.
For masonry I think to remember UBC-94, only of such kind of US codes I have gives specifications abot the maximun strength of anchors to masonry. In fact I made some Quattro Pro spreadsheets some years ago that I am now unable to run due to lack of memory -QP wants to run almost alone in w95- but will check if your case is covered. If I find would post the strength.
Were it an anchor to concrete, the procedures in ACI clearly would define the capacity for ordinary cases, shear or shear plus tension.
For masonry I think to remember UBC-94, only of such kind of US codes I have gives specifications abot the maximun strength of anchors to masonry. In fact I made some Quattro Pro spreadsheets some years ago that I am now unable to run due to lack of memory -QP wants to run almost alone in w95- but will check if your case is covered. If I find would post the strength.
I think that the shear strength of a steel bar in a concrete-masonary interface will seldom be the controlling factor.
Under load the steel will tend to deform to an S-shape as the concrete crushes slightly at the interface. Then you will not have pure shear at the interface, and the controlling factors are concrete (or masonary) strength, and steel bending and tensile strength and also pullout strength of the steel into the concrete.
Be careful that if you have changed from threaded bar to smooth bar, the pullout strength may be reduced because of less effective bond.
Under load the steel will tend to deform to an S-shape as the concrete crushes slightly at the interface. Then you will not have pure shear at the interface, and the controlling factors are concrete (or masonary) strength, and steel bending and tensile strength and also pullout strength of the steel into the concrete.
Be careful that if you have changed from threaded bar to smooth bar, the pullout strength may be reduced because of less effective bond.
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