Q. Necessity of pile tip cover for rock-socketed H-piles?

In current practice concrete cover is generally provided at the pile tips of pre-bored H-piles socketed in rock. The objective of such arrangement is to avoid the potential occurrence of corrosion to H-piles just in case concrete cover isn't designed at pile tips. Though recent field andlaboratory observations had reservation of this viewpoint. In case H-piles are designed to be placed directly on top of rock surface, it provides tip resistance to limit the pile movement in the event of bond rupture between H-piles and grout. Some contractors can choose to tamp the H-piles by employing drop hammers to make sure the H-piles are founded directly on top of rock surface. Practically speaking, it poses difficulties at the time of process of tamping since there is a chance of possible buckling of long H-piles when too much energy is provided to piles.