Punching shear perimeter - EUROCODE

[Djidji444]

Hello
I am interested in where the critical section is located when I look at the puching of a column or pile through the footing.

Unfortunately, I have very limited space for the pile footing (pile cap) and really big tension and pressure forces in the columns (therefore also in the piles) - it's very eccentrically loaded foundation: footing (pile cap)+piles.
My case looks like this - in blue are the dimensions of the footing/pile cap(2.0x2.4m) and the concrete bases (0.6x0.6m) of the 3D lattice column.Thickness of the footing is 1.4m for now.
In red are the piles with a diameter of 400 mm (I don't even have space left for a larger pile diameter):

Is my punching shear perimeter at 2*d like in the picture below:

Because considering that I have a relatively thick footing (pile cap), the 2*d perimeter goes outside the dimensions of the foundation.
And since it is a thicker footing, the beam theory is not valid I guess and I should switch to the strut and tie method, but I don't know how to apply it (it would me 3D strut and tie model whith half of piles in tension and half of it in pressure under wind combination).
Is there any way I can find out where is my control perimeter for the punching of these posts/piles through my thick footing?
Is it on d/2 or somewhere else? Is it defined somewhere in the Eurocode where it is for such thick footings or can it be manually calculated depending on the thickness of the foundation footing (and also be in accordance with the Eurocode)?

Do you even calculate punching of pile through footing (pile cap) or only punching of column through footing (pile cap)?

Thanks for your help in advance.

 

[KootK]

When punching shear checks are appropriate, they do apply to both the piles and the columns.

When punching shear critical perimeters overlap, that is often taken as sign that STM is a more appropriate design methodology than is punching shear, as you rightly identified above.

A strut and tie design should be pretty straight forward here. Two of your supported columns land right above piles and, as such, won't tax the pile cap meaningfully. The one column that land between columns can probably just bee designed as though it were sitting on a two pile cap that spans between the piles to the left and right of the column.