Piled Raft 1

[slickdeals]

Folks,
When you have a mat foundation supported on piles or for that matter a structural slab on piles with no drop cap or slab thickening around the pile, the piles typically extend 3-4" into the slab.

How do you account for the punching shear depth? Do you account for some reduction in depth due to this discontinuity? You still have the full depth at d/2 from the face but there is a discontinuity as the slab goes over the column.

 

[DaveAtkins]

I typically assume the pile extends 6" up into the mat, and I only use the concrete above this to check bending and punching shear.

DaveAtkins

 

[paddingtongreen]

Same as Dave, "d" for this calculation is the distance from the top of the pile to the top of the concrete.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[hokie66]

I agree that any projection of the piles must be deducted from the depth of the slab for punching shear purposes. However, for mat slabs as opposed to individual pile caps, I don't show the piles projecting into the slab. Piles are just columns in the ground, and other columns don't extend above slab soffits.

 

[DaveAtkins]

The CRSI Handbook says "A minimum embedment of 6 inches has been established as good practice with structural steel shapes to avoid the use of cover plates for bearing."

DaveAtkins