App. D. - Interaction with Vx AND Vy?? 2

[JAE]

The whole of Appendix D in ACI 318-05, indicates capacities for multiple failure modes in tension ([φ]Nn and [φ]Vn).

They even offer an interaction equation when you have both tension and shear.

Fine.

But what would be the proper calculation to use if you had shear in two directions (Vux and Vuy)?

Do you calculate a [φ]Vnx and then a [φ]Vny and then add this to the interaction equation D-31?

In other words:

As ACI published it:

Nua / [&phi;]Nn + Vua / [&phi;]Vn < 1.2

As I would suggest:

Nua / [&phi;]Nn + Vuax / [&phi;]Vnx + Vuay / [&phi;]Vny < 1.2

Does this make sense? ACI says nothing about x and y shear - it seems to assume that you will only have one shear direction.

 

[civilperson]

Add the shears as a vector to produce one total at right angles to the anchor. Square root of the sum of the squares.

 

[JAE]

Can you point to where in App D it says you can do this? I don't see it.

The problem with a vector is that the [&phi;]Vn values are based on ca1 anchor-to-edge distances that are determined from the anchor in the direction of the force - If you use a vector at some angle you have no true ca1 to use.

No examples I've seen deal with this - all very simple (typical academia examples).

 

[PackerFan]

It is hidden in RD.6.2.1.

You need to check the component in the x direction and the y direction and take the minimum of the two.

Please see the attached file on page 38 and 39 for a description of this.

http://www.yousendit.com/download/Y2o5SXR5OC9PSHcwTVE9PQ

 

[JAE]

Thank you.

 

[frv]

Star for PackerFan!

Not for the link, but for your choice of team!

 

[JAE]

Harumph.....go vikings (someday)

 

[frv]

Dang! and this whole time I've respected you, JAE... I feel dirty! (jk)

 

[JAE]

frv....ok - does it help that my favorite college team (my alma mater) also sucks at football?

And my uncle once tried out for the Packers as a kicker - new one of their coaches real well - and knew Ray Nitschke and Donny Anderson....so it's in my family to be a packer - but just wasn't to be.

Long time ago - sitting on my grandpa's lap watching football (age 5 or 6 maybe) and seeing football with black-and-white TV - I thought all the teams were the "black shirt" guys and the "white shirt" guys - both with white pants. Only two teams in the universe as I understood it.

I then one day saw a team with black pants, white shirts, and black helmets. They looked sooo cool. I asked my grandpa - "Who are they?". He answered, "That's the Minnesota Vikings." I answered, "That's my favorite team."

I've been a fan (slave) ever since.

 

[frv]

That's a great story, JAE!

It's been fun watching the two teams over the last decade or so.

Used to be the Bears were the worst nemesis of the packers.. but they were so bad that the rivalry between the Vikings and Packers heated up more than ever.. Those were actually fun games to watch.. records never really meant anything (and still don't).. they just go at it like playground kids...

 

[JAE]

With Favre being the biggest playground kid ever.

M = wL^2 / 8 (token engineering content)

 

[PackerFan]

I am a Madison, WI transplant living in Minneapolis so it's hard being a Packer fan up here. Thank god for Sunday Ticket on Direct TV.