Shear strength acc. ACI 318R-02

[bender36]

Hi,

the shear strength provided by concret Vc is given in clause 11.3.1.1. The version which I have says:

Vc=2*(sqrt(fc')/6*bw*d

in the internet I found:

Vc=sqrt(fc')/6*bw*d, but realted to the same code release.

Same appwears for the limit of Vs (clause 11.5.6.9):

Vs=8*sqrt(fc')*bw*d

and

Vs=2/3*sqrt(fc')*bw*d

WHAT IS CORRECT ?

Thank you very much,

Martin

 

[sdz]

Upgrade to the latest edition and go metric. ACI 318M-05.

 

[JAE]

I'm not sure where you get the /6 in the Vc formula.

ACI 11.3.1.1, Equation 11-3 shows:

Vc = 2([√]f'c)b_wd

The value in section 11.5.6.9:

Vs = 8([√]f'c)b_wd
is a maximum limit on your steel shear reinforcing contribution.

I don't see where there is a Vs = 2/3([√]f'c)b_wd

Vc and Vs are two different things.

 

[csd72]

bender35,

When you use a new formula that you are no sure about, check it to make sure it makes sense. In your case a higher area would have resulted in a lower shear capacity - obviously something was wrong.

It doesnt work so well on this formula, but usually putting the units into the formula should give you the correct units as a result (i.e kips/lbs for a force or psi for a stress).

 

[magudfe]

Check in ACI 318-05 (SI units), you will find:
11.3.1.1, Equation 11-3
Vc = 0.17(?f'c)bwd
11.5.7.9:
Vs = 0.66(?f'c)bwd

 

[ahmedhegazi]

the first you mention for Vc and Vs are in imperial units, the second are in Metric units