I have a structural asking me if he could use steel tips for square concrete piles to assist in pile driving. I have not heard of this application before AND I wonder whether it is appropriate to use steel tips for end bearing piles in soft rock. Anybody?
In principle, there is nothing wrong with using steel driving shoes on the piles. However, you must examine the reason for introducing the shoes. If it is because a blunt-ended concrete pile might meet with too much driving resistance, consider whether the pile shaft has the capacity to resist the driving impact forces.
The shoe should ideally be cast onto the pile end.
However, I have never used them myself. An experienced piling contractor's view would be very useful.
I have seen rock tips for concrete piles. They have a harden steel pin on a square base that is cast into the pile. A varible stroke hammer is needed to drive them. As soon as the pile reaches rock, the driviing energy is imeadiately cut way back and the pile is gently tapped to set the pin in the rock. I don't have the literature in front of me, but you pile precaster could tell you who to contact. There is a sweedish product that is very good. The tips are not cheap, and anytime you try to drive precast to a hard bottom, there will be some breakage of piles, no matter who is driving them. Good luck.