Pile-tip cap driving method for precast concrete pile

Precast concrete piles have been mainly driven into the ground by using diesel hammer. Unfortunately, to drive the piles with diesel hammer causes a lot of unavoidable and unplesant problems, such as noise, vibration and oil splash around the construction site. Pile-tip cap driving method for precast concrete pile is now developed. The tip of hollow precast concrete pile is coupled with steel cap. The cap is driven by dropping a hammer through its central longitudinal hollow as well as the pile itself is advanced by another hammer on the pile top. This pile-tip cap driving method has less noise and quake levels which are below the allowable values of the Japanese regulations for the specified construction work and no significant oil splashes. Based on basic energy equation, a dynamic formula for estimating the allowable bearing capacity of pile is proposed. A calculated value from this formula using last penetration shows good results close to the field measurements. Furthermore, finite element analysis on a model related to this method gives higher driving efficiency than the conventional pile driving method on pile top.