CFA piles keep compact sites vibration-free
CFA piles are a good option on sites where existing structures are located close to the area where piling is taking place.
With many construction projects based on plots of land whose neighbouring units have already been developed, a non-invasive method of laying new foundations is increasingly important.
CFA piles – or Continuous Flight Auger piles, to use their full name – help to overcome this issue by cutting down on the vibration caused by downward drilling.
They are installed by drilling into the ground with a hollow auger, until the desired depth is reached.
Piling medium is then pumped into this hollow vertical pipe, while the auger is withdrawn – reinforcing cages can be inserted into the still-wet concrete once the auger itself is clear of the pile.
The process can be achieved with more compact piling rigs than some other methods, and causes relatively little disruption to the surrounding ground – this is good not only for nearby foundations, but also for underground infrastructure such as gas and water pipes.
If your project needs concrete piles, but you are short on room to manoeuvre, CFA piles could be the ideal option, as well as helping to ensure you stay within acceptable vibration limits if working on a site with occupied neighbouring premises.
Concrete piles are cancer-free
Concrete piles are still a strong support for any structure, despite recent reports to the contrary.
The Hammersmith Flyover was closed in late December 2011, due to structural concerns, leading to reports of ‘concrete cancer’ in its supports.
But the Mineral Products Association has pointed out that the problem was not in the concrete itself, but in the internal steel cables of the flyover.
These had corroded due to saltwater – which, in turn, had been created through gritting the road, instead of heating it from beneath as originally intended.
“It is regrettable that concrete, which is such an essential material for both existing and future infrastructure, has been misrepresented in such tabloid terms,” says MPA chief executive Nigel Jackson.
The story highlights the importance of understanding the materials used, in order to keep them in good condition for the long term.
However, it is also important to recognise that the problem was not as reported by some parts of the press – and concrete piles are still a strong and reliable option.
With pre-cast concrete piles available to bring in from off-site, construction projects can continue at a good pace, while ensuring the most important parts of the finished structure are made to a high standard by specialists.
Underpinning foundations can tackle expansive soils
Underpinning foundations is a good way to create stability in soils that are not stable enough to support structures on their own.
Expansive soils are a particular cause for concern – these are where changes in moisture content can make the ground expand or contract by quite a large amount.
Following a fairly dry 2011, soils in many areas are likely to be much drier than they would ordinarily be, making some construction projects unpredictable.
In England, for example, Met Office estimates for the whole of 2011 are that rainfall was just 84% of its normal level.
Even in December, England’s rainfall was down, at 99% of its expected average for the month.
With this in mind, builders could find dry soils are unable to support foundations as well as they ordinarily would do – and some already-completed buildings may well develop foundation problems, too.
By underpinning foundations to help improve their stability, construction projects can be kept on track, and completed structures safeguarded.
With the Met Office forecasting a warmer-than-average year for 2012 as well, the need to underpin foundations could arise more often in the future, as soils dry out and offer less support than they have done in years gone by.
Sheet piling keeps construction sure-footed
Sheet piling has many applications, from hiding a construction site against prying eyes, to keeping trespassers out and controlling access points.
But another use for sheet piling is to protect the site against the elements, as interlocking piling can create a temporary or permanent wall around the edge.
With wet weather likely in the weeks and months leading up to the summer, keeping water off of the site can be a good first step towards maintaining safe underfoot conditions.
HSE guidance warns that, if surfaces below foot are allowed to become muddy, they may need covering or treating with stone to avoid slips and falls.
Sheet piling is a good first step towards preventing this from happening – and even if the ground does become muddy, you should be able to avoid the worst of any minor floods that take place when the spring rains arrive.
Choose your sheet piling based on how long it needs to remain in place.
Temporary sheet piling is perfect for building sites that need privacy against passers-by, but where the wall created is not a lasting part of the plans.
Permanent sheet piling, meanwhile, can quickly create a retaining wall during construction, which can then be left afterwards for architectural or safety reasons.