NOBBY’S KNOWLEDGE

PRE-CAST PILES

Due to the nature of this type of piling and the various specifications encountered in the pile manufacture, APC recommend a quick phone-call or Email to the office confirming the pile specs so we can match the pile to the cropper required, as we have different croppers which attain different outcomes.

Please see the contact us page for further details.

AUGERED PILES – THE TWO METHODS – BONDED OR DEBONDED?

 

Ok………………. So, isn’t it time to join the space age?

Whilst Jackhammers have been pretty useful over the years as an adequate pile reduction tool the time has come for a giant leap forward in pile reduction, specifically in the manner of working on CFA piles.

As anyone who has performed any process of work methodology, the secret to a perfect finish is all in the preparation. This is the goal of APC; to advance the breakdown of piles into the most effective method – but this does require prior thinking and planning.

If you are faced with a situation where the pile to be broken down is the traditional – drilled / grouted / cage inserted method with no prior cage preparation then we have the machine for you in the CFA cropper which can be increased / decreased in size to facilitate all pile sizes.

If, however, you can integrate the debonded method in your cage design then this allows the use of the QUAD machines which (we consider) will give you the “Gold Standard” in pile breakdown with (amongst other things) reduced time, reduced dust, cleaner cuts… the benefits go on.

AUGERED PILES – THE TWO METHODS – BONDED OR DEBONDED?

 

Ok………………. So isn’t it time to join the space age?

Whilst Jackhammers have been pretty useful over the years as an adequate pile reduction tool, the time has come for a giant leap forward in pile reduction, specifically in the manner of working on CFA piles.

As anyone who has performed any process of work methodology, the secret to a perfect finish is all in the preparation. This is the goal of APC; to advance the breakdown of piles into the most effective method – but this does require prior thinking and planning.

If you are faced with a situation where the pile to be broken down is the traditional – drilled / grouted / cage inserted method with no prior cage preparation then we have the machine for you in the CFA cropper which can be increased / decreased in size to facilitate all pile sizes.

If, however, you can integrate the debonded method in your cage design then this allows the use of the QUAD machines which (we consider) will give you the “Gold Standard” in pile breakdown with (amongst other things) reduced time, reduced dust, cleaner cuts… the benefits go on.

Did someone say CHEESE?…

Did someone say CARROTS?…

So you may want –

A – Clean finished level cut pile

B – Minimum cuts

C – Clean reinforcing bar

D – Minimum spillage around the pile

E – Minimal airborne dust / Minimal noise in the breakdown

Who wouldn’t want those things!?  Shhhh……..……… Let me tell you a secret – you can have all of that in a few simple and easy steps like this:

1 – Cage Preparation

 

The whole idea of the debonded method is that the waste or superfluous concrete at the top of the pile is cut cleanly and removed in the least time possible. To enable this, the cut concrete (THE “CHEESE” – it even has holes in it!!!) has to be able to slide off the pile without restriction therefore there are 2 factors required to be considered in the Cage preparation:

A – Radial cage spirals need to stop at a distance greater than the perceived final site RL – Example – Nominal 1m un-welded and spiral free for the “Cheese” to slide off the reinforcing cage.

B – The spiral free lengths are fitted with a compressible debonding agent – NOT SPRAY RESIN.

1 – Cage Preparation

The whole idea of the debonded method is that the waste or superfluous concrete at the top of the pile is cut cleanly and removed in the least time possible. To enable this the cut concrete (THE “CHEESE” – it even has holes in it!!!) has to be able to slide off the pile without restriction therefore there are 2 factors required to be considered in the Cage preparation:

A – Radial cage spirals need to stop at a distance greater than the perceived final site RL – Example – Nominal 1m un- welded and spiral free for the “Cheese” to slide off the reinforcing cage.

B – The spiral free lengths are fitted with a compressible debonding agent – NOT SPRAY RESIN.

2 – DeBonding

This is the magic ingredient in the process – pipe insulation tubing!!

Simply slid over the free length of the reinforcing bars and secured with cage wire (loosely – it needs to be able to slide off), this tubing is readily deformed due to its elastomeric properties and can be compressed by hand quite easily. However, it makes the perfect agent for the process of not allowing the pile grout to form on the reinforcing bar and due to its properties it allows the pile to “cleave” under the force of the cropper jaws.

Now……….. For the sciencey bit………………….

All of the APC Quad croppers utilise four synchronised radial arms which exert massive force on the piles radially to the cage. The compressible debonding agent allows an engineered break point in the pile at right angles to its required full strength. The cropper jaws exploit this break point by generating a cleavage, due to the massive force, at the opposing four points and due to the fact the debonding agent allows the pile to deform at these points. It eventually cleaves around the cage and snaps or “pops” the remaining grout inside of the pile like a carrot. Once loose, and without any radial hoops or restrictions, the excess pile “Cheese” is simply slid off the pile and discarded. The process is simple and repeated until the correct on site RL is achieved.

Just to recap:

 

Pipe Insulation Tubing – Debonding Agent

Cages Debonded Ready for Embedment

Cropped Cheeses – Snapped Like a Carrot!!!

Final Cropped Piles – Clean and at RL

SECANT AND CONTIGUOUS PILE WALLS –

As the drawing above explains; both the QUAD and the CONTIG style of cropper can be utilised on Secant and Contiguous wall designs, ideally the cages have been debonded and have all the prerequisite preparation, as per the stated methodology. Secant piles will require the female pile to be removed (Jackhammered) and then the cropper can be used on the male piles in the normal manner. 

Dependant on pile size and cropper used, the minimum distances between piles can be a little as 50mm for the CONTIG and 100mm for the QUAD.

Please contact us for more information if required.

EVOLUTION (of Pile Cropping)