Details about cut-off level in pile foundation
Pile Cut-off level belongs to the actual level at which the piles underneath the pier are constructed so as to retain the same level. The concrete of pile is cut-off at the certain level (provided in the specifications or drawings normally around 75 mm) whereas the steel is arranged in-to the pile cap to maintain a strong connection among pile cap and piles.
The reason for trimming or cutting of pile
The Piles which are casted in dry bore holes when employing temporary casing, piles heads should be casted to a level a bit over the specified cut-off in such a way that after cutting or trimming, a strong bonding of concrete is formed with the pile.
When the piles are casted under water, tremie method of concreting should be applied. Under this method, the shaft of concrete pile is casted with a tremie pipe that is dropped under the water level or the interfacing concrete and pouring of concrete is done with pressure when the slurry and other raw concrete or weak concrete emerges. For tremie method, slump mix should be provided in excess of 175 mm.
Pile cut-off level is located over or under the group. When it is over the ground, Concrete will run over from the pile head on execution. Because of tremie method, the upper section of pile comprises of weak concrete and some impure boring debris.
When the pile cuts-off under the ground, the concrete level should be increased to provide for around 1 m for trimming off the weak concrete.
Usually, the cropping or trimming process is performed to attain the essential cut off level with a jackhammer or hand-arm vibration syndrome (HAVS).