Punching shear pile cap. perimeter encloses many piles
Punching shear pile cap. perimeter encloses many piles
(OP)
I have pile cap, huge pile cap 88.4m by 28.4m 7m deep. 28 2.5m diameter piles at 7.5 m spacing. the 1.5d perimeter encloses 4 piles! does that mean i include the 4 pile loads in the punching shear check. or should i just include the one pile, and the shear stress at 1.5d is just due to the single pile. in reality that isn't the case. the shear stress at 1.5d perimeter will be due to whatever is within the 1.5d, i.e the 4 piles inside the perimeter.
hmmmm
any ideas guys?
hmmmm
any ideas guys?






RE: Punching shear pile cap. perimeter encloses many piles
Probably can't fail in punching shear from a single pile. I see it as similar to headed studs. You can check a single pile but a more realistic approach would be a group of piles with the punching shear perimeter.
RE: Punching shear pile cap. perimeter encloses many piles
i shall use a reduced perimeter, which of course will result in an increase in shear stress! sya hello to shear links. 7m long!
RE: Punching shear pile cap. perimeter encloses many piles
To support the top reinforcement, you will need some substantial bars anyway, so they will by default serve as stirrups.
RE: Punching shear pile cap. perimeter encloses many piles
It's no trick to get the answers when you have all the data. The trick is to get the answers when you only have half the data and half that is wrong and you don't know which half - LORD KELVIN
RE: Punching shear pile cap. perimeter encloses many piles
It would be worthwhile looking at some case studies for raft foundations for supertalls like the burj or similar. Some of them use a combined rock bearing-pile bearing system.
I would think that beam shear would be critical because the pile reactions to the underside of the raft will begin to overlap and one-way shear becomes the failure mechanism.
RE: Punching shear pile cap. perimeter encloses many piles
I did toy with strut and tie, but for so many piles and load cases. it seems very complicated!
the problem is thes say eurocode and bs 5400 is based on building slab design. so it doesnt really work. i have yet to see a bridge pile cap fall down though!