Allowable Wide-Beam and Diagonal-Tension Shear by ACI code 1

[XinLok]

I searched hard to find out where the Table 3-2 without success.

Does anyone known in which part to ACI code 318-11 this table 3.2 exist?

 

[JAE]

That table is not from the ACI 318 document. In ACI 318, shear was always in Chapter 11.
This table appears to be from a text book or some other reference that takes the provisions of 318 and tabulated them.

 

[JAE]

This might help:

 

[XinLok]

So the above table cannot be trusted?
Is there any table can be used in ACI 318-11 to get Vc from f'c?
I would like to get such table to help in recognizing the depth of footing.

 

[JAE]

To get Vc from f’c I would simply use the 318 document - the formulae are not difficult. I’ve never used or needed a table.

 

[XinLok]

Yes you are right, the formulae is easy as pie.

But if I have d unknown, then I won't be able to get the Vc.

Therefore in order to get estimated value of d, I have to get a value of vc from a table, then I will be having an equation which can be resolved and I can get the value of "d"

Let me know please if I am wrong.

Thanks

 

[JAE]

Not having a "d" is not a significant challenge.
If you know your Φvc stress (from the ACI formulae), and you know your Vu demand, simply back calculate the required d value.

Or simply try a d that you think might work, and see how the numbers come out.

I'm not sure why this is seen as difficult.???

 

[XinLok]

Appreciate your support JAE,

let me explain:

according to this Screenshot, we have 2 values for d, and in order to calculate these 2 values, we should have vc, otherwise we will have 3 unknowns.

Am I wrong?

 

[jayrod12]

But you have Vc in terms of d. You can substitute and do the algebra. Standard math type stuff.

Or, generate a spreadsheet where you guess a d, solve through and check the calculated d against the guess. Iterate until the two converge.

 

[XinLok]

For oneway shear verification, it is okay.
But for two way shear penetration verification, for me it is an issue finding the minimum d

 

[jayrod12]

No it's still just algebra and iteration. Guess, plug, check, repeat until the guess d and the calculated d match up.