Bottom-Driven Piles

Grundomat Systems:

These consist of a sacrificial thin wall casing usually of smaller diameters. The starter length is crimped to a point at one end for driving, with the latter lengths added as the pile progresses, these lengths are termed “followers”. The pneumatic hammer drives inside the first length and when this length is driven to depth, the follower length will be welded into the lead length. The casings are manufactured specifically to allow the following length to slide inside the previous length so that the joint can be welded.

The hammer inside the tube drives the casings to the required depth, hence the term bottom driven piles. During the design, the designer will identify the minimum set acceptable to prove the capacity of the pile and the teams on site use this as the criteria for completing a pile. The set will generally be a measurement of the number of blows for 10mm advancement. This is advised at the design stage.

Once the casings are at depth, any reinforcement can be placed in the pile centrally and either grouted or concreted. Grout or concrete cubes are taken and submitted for testing at an approved testing lab.

 

Drop Weight Rig:

If working areas are not as restricted, these bottom driven piles, which can go up to larger diameters and length, can be driven into the set position using a D500 or a D1000 Drop Weight Rig.  Again, these are bottom driven piles and are installed by the same method as the Grundomat Piles, using a starter casing and followers, driven to the predetermined set.

Once the casings are at depth, any reinforcement can be placed in the pile centrally and either grouted or concreted. Grout or concrete cubes are taken and submitted for testing at an approved testing lab.

These are driven displacement piles typically used in poor ground where the piles are used for end bearing in dense strata at depth. This is not vibration free.