The tips of concrete piles may be crushed in compression under hard driving. For hard driving conditions, or for end bearing on rock, special steel points can be attached to the tip. A common type of tip protection is a structural H section at the toe of the pile. H-pile ends for prestressed concrete piles can have the bottom end protected with an H-Pile Point as a means for penetrating difficult strata or extending the length of the pile. Several methods have proved satisfactory for attaching the extension; one of these is shown at the right.
The PCI (Prestressed Concrete Institute) suggests an H pile “stinger” for tip protection and extension of prestressed concrete piles. With cast steel point protection on the H Pile, firm embedment can be obtained as well as a foothold on rock at an angle to the axis of the pile.
Cast iron or steel shoes or the “Oslo Point” are also used frequently. The characteristics of the “Oslo Point” are such that it can be chiselled into any type of rock to ensure proper seating. This is shown at the right. These points are especially useful with pretensioned spun concrete piles.
Other cast steel point protection is available, most of which are of European design. Most of these devices are planned for attachment in the concrete casting bed. Attaching the point may be complicated due to having to work around the prestressing wires, all of which are continuous throughout the length of the casting bed.
All point attachments to concrete piles are attached during casting of the piles and not in field.