AJ Hurst Foundation Engineering

Rotary Bored Piling Continuous Flight Auger (CFA) Bored Piles Driven Piling Tripod Bored Piling Mini Piling Underpinning Other Services

A J Hurst (Foundation Engineering) Ltd was formed in 2004 and it trades under the name AJH Piling. Alan Hurst started the company after many years of working in the industry for the most part controlling operations in the North of England for two of the UK’s major piling and geotechnical companies. He has also gained further geotechnical experience managing a number of such projects for companies in various parts of the Middle East during the late 1970s/early 19 80s

A J Hurst (Foundation Engineering) Ltd
Unit 9G2, Carcroft Enterprise Park
Station Road, Carcroft
Near Doncaster DN6 8DD

TEL: +44 (0)1302 339 300
FAX: +44 (0)1302 339 600
EMAIL: alan.hurst@ajhpiling.co.uk

AJ Hurst Piling Foundation Engineering Ltd

AJH Piling is a technically driven organisation that will always try to give best advice to the construction industry on piling and foundations even when this advice is to use a system they are not able to offer themselves.

The photographs show the largest and smallest rigs indicating the range of equipment we have at our disposal and we welcome any piling enquiries no matter how complex or difficult. AJH Piling specialise in

difficult sites and with experience and full design capabilities AJH Piling are often able to offer innovative design packages.

The choice of a particular pile type on any project can sometimes be somewhat arbitrary and regrettably in some exceptional circumstances the wrong choice may put an unnecessary financial burden on the contract and in extreme cases result in failure of the work.

Cost is usually the main consideration although it is important not to lose sight of the quality of the final product in the particular ground condition, and although the various comparative pile costs can approximately be summarised as in the table below (where A is the least expensive, and F the most expensive). This should be taken as a guide rather than definitive answer for all situations.

AJ Hurst Piling Foundation Engineering Ltd

No	Price Category	Pile Type Capacity	Brief Description
1	A	Driven Cast-in-Place Loads up to 1000kn	A steel tube with a shoe or plug is hammered to the required depth or set, steel rebar and concrete added and the tube extracted, to drive at the next location.
2	A	Pre-cast Pile Loads up to 1000kn	Factory made concrete pile delivered to site by lorry normally in lengths or segments up to 13metres that can be driven/hammered to the required depth or set. Uses mechanical joints to connect segments for pile depth greater than 13m.
3	A	C.F.A Loads up to 2000 kn or higher	A suitably long continuous hollow stemmed auger is screwed to the required depth, concrete or grout is pumped through the stem replacing the material bored by the auger as it is extracted. The remaining concrete column is reinforced with a limited length of rebar cage. Can be bored using smaller rig adding and removing augers.
4	B	C.H.D Loads up to 600kn depends on strata	As with CFA above, this pile is formed by screwing an auger to the founding depth, pumping concrete through the centre stem, and reinforcing concrete column by adding a short cage. The difference is the auger is designed to displace and compact soil rather than remove it.
5	B to C	Rotary (Small) Bored Pile Loads 2000 kn or higher	This pile is formed by using a short auger to extract soil, and where necessary inserting casing to support the ground. When the required depth is reached rebar is inserted and the hole is concreted up to the required level.
6	C	Mini Driven 450 kn	Generally 250mm or smaller usually driven sacrificial steel tube or bars.
7	C to D	Mini Bored 600 kn	Usually less than 250 mm diam. formed by a variety of techniques (as described above with their larger counterparts) or combinations of same.
8	E	Tripod Bored Piliing 2000kn max	Bored pile using segmental casing and forming hole by percussive drop auger to remove soil.
9	E to F	Rotary (Large) Bored Pile 10,000kn and higher	Exactly as with 5 above, but used to form piles 600mm to 3000mm diameter. Sometimes requiring drilling fluids in place of long casings.

With this pricing structure in mind it is then important to revue the circumstances of the particular site to be piled to see what other factors might further influence the choice.

The list below is for guidance and is far from exhaustive. Any of the ratings below from 0 to 5 are somewhat subjective but most piling contractors would accept them as being a reasonable guide:-

WHERE most suitable pile type is 5, and least suitable 0

*** Please note *** no pile type is particularly able to deal with obstructions and they are better removed before the piling work commences.

Many claims and disputes arise from the wrong pile type being selected initially and what may at first inspection appear to be an inexpensive solution may turn out to be more costly when the final account arrives.

There is a growing tendency to economise on foundation costs, and by doing the minimum amount of site investigation (or even none) the client leaves the Main Contractor and piling contractor to get into a contract based on assumptions. If those assumptions prove correct the contract will proceed without problems but when

they prove to be incorrect they end up in a dispute which benefits none of the parties.

Foundations are arguably the most important part of any structure, they are seldom seen, and are neglected at the developer/owners peril. They are also one of the most difficult areas of the Building and Civil Engineering industry and the best way to avoid problems and unnecessary costs is to obtain good information about the ground and seek the advice of an experienced specialist contractor who is without a vested interest in one pile type over another.