Punching check for piles close to each other

[Brd Eng]

Do we have to check the punching from piles in the pile cap from individual piles with reduced perimeter from overlapping perimeter or calculate the punching for perimeter at a distance where the perimter does not overlap with other pile perimeter? Should we also check punching due to grouo effect of piles?
Punching needs to be checked with the perimter at distance 1d to 2d. If my punching resistance is ok at 1d then do i have to check at 2d distance also? At 2d distance, perimeter will be increased and my shear stress will be reduced?

 

[KootK]

Got the doc below? It's great for this kind of thing.

 

[SWComposites]

At 2d distance, perimeter will be increased and my shear stress will be reduced?

yes, but is the structural capacity the same at that distance?

 

[Nick6781]

Do we have to check the punching from piles in the pile cap from individual piles with reduced perimeter from overlapping perimeter or calculate the punching for perimeter at a distance where the perimter does not overlap with other pile perimeter? Should we also check punching due to grouo effect of piles?
Punching needs to be checked with the perimter at distance 1d to 2d. If my punching resistance is ok at 1d then do i have to check at 2d distance also? At 2d distance, perimeter will be increased and my shear stress will be reduced?

Check the document KootK mentioned. You'll find your answers there.

 

[Brd Eng]

I have an arrangement like this on pile cap where circular piles are used and on top of pile cap i directly have bearings. The pile cap is itself loaded with wave, ice, wind load and bearing reaction for superstructure load. How to design this pile cap using strut and tie method and if i check punching for individual pile at 2d then there will be over lapping of the perimeter.

 

[KootK]

This will depend on the dimensions involved, including the thickness of the pile cap.

The bearing at the top left is clearly an STM thing and will not significantly affect it's neighbor's punching capacities for the worse.

I suspect that the top right bearing is the same. Perhaps even the lower right.

Where the overlap is pretty meaningless in the sense that I've described it, you can probably just conservatively treat the bearings as isolated conditions.