## Shear/Tension capacity of rebar?

## Shear/Tension capacity of rebar?

(OP)

I think is this probably a stupid question, but I'll be damned if I can't figure it out or find it anywhere in my texts. I think it would simply be As x fy. But that seems too simple. I guess maybe you need to multiply by a phi value as well...0.7, 0.8?

I am asking because I am trying to determine the pull out strength of a rebar grouted into rock, as well as the shear capacity of that same rebar, grouted into rock. What about a bolt, threaded rod, etc...? Same idea as rebar?

It's been a long week....

I am asking because I am trying to determine the pull out strength of a rebar grouted into rock, as well as the shear capacity of that same rebar, grouted into rock. What about a bolt, threaded rod, etc...? Same idea as rebar?

It's been a long week....

## RE: Shear/Tension capacity of rebar?

Usually dowels are limited by bearing with the concrete rather than shear.

What is the situation?

## RE: Shear/Tension capacity of rebar?

Don Phillips

http://worthingtonengineering.com

## RE: Shear/Tension capacity of rebar?

My Ramset anchoring book gives this:

N*/Phi_Nu + V*/Phi_Vu < 1.2

There are non-linear interaction formulas too.

As noted by the other posters, you are unlikely to fail the bar.

## RE: Shear/Tension capacity of rebar?

## RE: Shear/Tension capacity of rebar?

But more than just that I am trying to learn how this actually works, and to find the "correct" way to determine these types of things. I am somewhat of the loan structural engineer in my office and there isn't anyone in to discuss this kind of stuff with, so I am forced to figure it out on my own and it can be quite daunting at times. Thank gooodness for the internet.

## RE: Shear/Tension capacity of rebar?

## RE: Shear/Tension capacity of rebar?

## RE: Shear/Tension capacity of rebar?

I emphasize "start", since, as previously stated, this is a coeff, not a safety factor. Also I am basing my "start" coefficient on AISC 9th 5-148, F4, which is for carbon steel, not for rebar. To my knolwedge there is not a specification for shear in rebar. Why? I don't know! Threrfore, if I were to do this, proceeding with caution, I would compare my results with that of mechanical fastener specification and design manual data.

So, to elaborate on the original question, how do mechanical fastener manufacturers, come up with shear values? i.e. Powers Fasteners Specification and Design Manual, 5th edition p. 189.

## RE: Shear/Tension capacity of rebar?

First, factor your shear forces to get your design shear, Vu.

Your resistance, is this case, will be limited by the steel shear strength and the pryout shrength of the anchor.

The steel strength, phiVs=phi*0.6*As*min(fu, 1.9fy)

for ASTM A615 Gr60 rebar/ phi=0.65, fu=90 ksi, fy=60ksi

Depending on your geometry, the shear strength could be limited by the pryout strength. The "nominal pryout strength" in shear is governed by Eq D-28. To get the pryout strength, To get the pryout strength, multiply the "nominal pryout strength" by the phi factor covered in article D4.4c.

## RE: Shear/Tension capacity of rebar?

## RE: Shear/Tension capacity of rebar?