Piling and Anchors
We offer design solutions for all types of piled foundation in common use in the UK:
Our design service in this field is second to none. Pile foundations are our specialist area of expertise and we have been responsible for the design of many tens of thousands of piles installed in the UK over the past two decades.
Piles can be separated into four main types:
Bored / Drilled (Replacement) Piles
Driven Preformed & Replacement Piles
We can identify the most suitable piling solution based upon the specific requirements of the structure and site.
Continuous Flight Auger (CFA)
Our experience with CFA (or auger cast) piles is extensive on both small and large diameter projects. We have designed piles in all UK and Irish ground conditions from weak alluvial soils through to moderately strong rocks. We are also very familiar with the capabilities of UK based CFA plant including the boreability of weak rocks.
Rotary bored piling is an excellent technique in the right ground conditions and again here we have extensive experience of this technique in London Clay and the heavily overconsoldated clays found in Southern England. We have also designed underreamed bases for these types of piles which is a technique that is finding itself more popular having overcome many safety issues.
The Driven Cast Insitu (DCI) pile is a pile that has become the norm for larger projects in Britains' estuarine locations, used commonly on the Humber, Severn and Thames estuaries the pile provides a quick and easy solution for low rise development and it is a pile type with which we have extensive experience.
Driven Precast Concrete (DPC) piles are an effective solution where large depths of alluvium overlie denser strata and can offer an effective foundation for both lightly and heavily loaded structures. Our experience with the precast concrete pile is again extensive and includes some of the largest single contracts awarded for this type of pile in the UK.
Driven steel piles come in various guises and whilst not a popular choice due to their cost, are still a pile that offer advantages in certain situations and one with which we are very familiar.
Driven Cast Insitu
Driven Precast Concrete
Driven Tube, Box and H Pile (steel)
For difficult access the mini or micropile offers the only practical technique. This market is also split into driven and bored types and is one of our main areas of concentration. We are highly experienced in the design of cased steel driven and all types of bored and drilled mini and micropiles. In addition to design we also offer a load testing service for mini and micropiles in restricted access using or patented system.
Self Drilling Micropiles
Self Drilling Micropiles use a hollow threadbar with a sacrificial drill bit which is drilled into the ground using grout as a flushing medium. This results in a grout body within the ground containing a high tensile steel bar. Corrosion is taken into account by typically over-specifying the bar with a sacrificial corrosion allowance and/or by the use of special coatings.
There has been a rapid uptake of the use of ‘self drillers’ in the UK in recent years and we have been at the forefront of this expansion. Working with the most up to date practice alongside the International Society for Micropiles (ISM) and conducting our own research (papers) we have been able to prove the benefits and capabilities of these versatile piles to the most demanding approval authorities.
Self drillers are quick to install and produce very little spoil, which means they are ideally suited to sites where ground contamination and costly disposal of spoil is an issue. Other key benefits are:
Ability to rake
Ability to penetrate obstructions
No requirement for casing
High grout penetration in granular soils producing high skin friction capacity
We can offer a design service for all types of ground anchors (rock bolts and soil nails) including; High Capacity Strand anchors, Bar anchors and Hollow threadbar anchors.
We have extensive design experience using high capacity strand or bar in soils and rocks throughout the UK.
High Capacity Strand Anchors are ideal for capacities in excess of 500 kN. We have designed strand anchors with safe working capacities of 3150 kN for high integrity nuclear safety structures.
Bar Anchors are suitable for loads up to 2000 kN where strand anchors cannot be used. We have designed many schemes using bar anchors from retaining structures to tank farms and continue to offer a design service for this type of anchor.
Hollow Threadbar Anchors are similar to self drillers. We have designed many projects using this technique particularly where a rapid solution in unstable soils is an important aspect