Innovative Piling Solution for Crossrail - continued
The technique also offers financial and environmental savings, in addition to a reduction in site traffic and a natural improvement in safety for road users. The aim of the development of this innovative technique was the reduction of material use and lorry movements than conventional rotary piles through the creation of a threaded rotary bored pile in London Clay.
This patented pile consists of a central core, with a helical thread formed around this – increasing the effective geotechnical diameter of the pile by 150 mm – this results in a considerable reduction in spoil and concrete volumes compared to traditional straight shafted piles to carry the same load.
The process is based upon standard pile construction techniques with the addition of a stage to create the thread on the pile bore.
Remote access inspection techniques, based upon those for inspection of under ream piles, are used to demonstrate the effectiveness of the threading process, combined with static load tests to validate the design assumptions.
Specially developed on-board electronic systems enable the operator to monitor thread formation and provide as built record information.
A pile with a threaded shaft also offered increased skin friction compared with an unthreaded shaft and therefore increased pile capacity by 40% for the project.
Barry Osborn, Contracts Manager, also added:
Over the 18 month period Bachy has been contracted to install forty seven 600 mm diameter, forty four 750 mm diameter and one hundred and twenty two 900 mm diameter conventional LDA piles, plus ninety seven 750 mm to 900 mm Sol Thread piles for the bus depot, whilst the new batching plant requires one hundred and four 750 mm diameter LDA piles.
These piles form the basis of the site’s facilities, which on completion will be home to Lafarge Tarmac, the concrete batching plant owner, Tower Transit the bus operator, Crossrail running lines & turn backs, and sidings for freight rail operators, DB Schenker.
Ade Adetoro concludes:
Our work at Paddington New Yard is by no means over. It’s certainly been a challenging project, but with innovative design techniques, an excellent partnership with both Costain and Crossrail and naturally a lot of hard work, the high profile project has proved to be a real success.
Solum Innovative Outrigger Pads
Solum (Europe) Limited has introduced a range of innovative, aluminium temporary foundations and crane outrigger pads.
The modular Solum units are available in a range of sizes, from 600 x 600 mm, capable of spreading a 20 t SWL to 600 x 1800 mm which can be used in a 5-pad arrangement to spread a 100 t SWL.
This engineered temporary foundation has been designed from first principles utilising finite element analysis to optimise strength, whilst keeping weight to a minimum. The lack of weight ensures the smaller units can be lifted, carried and placed by a single individual, with only two people needed to move the largest units, helping speed up on-site set ups.
Solum Technical Director Bob Quinn commented:
We designed the Solum so it could be laid in a variety of configurations to accommodate a large range of loads, yet remain light enough to be man-handleable. Our much-lighter Solum pads will make working around cranes a lot safer by significantly reducing the need to short rig.
The smallest pad can not only be used as a foundation for smaller crane loads, but also for falsework, propping and lorry loaders.
Although we were confident in our calculations, we put Solum units through rigorous independent testing with Lloyds British Group, the international leader in test, inspection and certification, to confirm the results of our extensive finite element analysis. Despite the light weight of each unit, they performed as predicted, with the innovative design able to spread the load throughout.