shear in circular RC columns 1

[wildehond]

I'm helping a geotechnical colleague in South Africa to calculate the shear capacity for different piles. The SA code doesn't give guidance on the calculation of Vc for circular columnns. My understanding is that ACI does. Can someone please help by posting the appropriate formula. Thanks in advance

 

[JAE]

wildehond,

ACI 318 states that the area used to compute Vc for circular columns can be taken as the product of the diameter and effective depth of the member. They then say that the effective depth, d, can be taken as 0.8 times the diameter.

So your "area" for Vc would be 0.80 x (diameter)²

This is in section 11.3.3 of ACI 318-05.

 

[amec2004]

For circular concrete section

1) Concrete shear resistance Vc, ACI 318-08 11.2.3 specifies effective shear depth dv = 0.8 dia, shear area = dia x dv

2) Circular tie resistance Vs, ACI 318-08 11.4.7.3 — Where circular ties, hoops, or spirals are used as shear reinforcement, Vs shall be computed using Eq. (11-15) where d is defined in 11.2.3 for circular members, [red]Av shall be taken as two times the area of the bar in a circular tie, hoop, or spiral [/red]at a spacing s, s is measured in a direction parallel to longitudinal reinforcement, and fyt is the specified yield strength of circular tie, hoop, or spiral reinforcement.

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[wildehond]

thanks to both of you for your help