Aspin’s easy solutions Micro Piling for OLE Masts
Client: Network Rail
Date/Duration: Completion: 2017
Rocky ground provides significant challenges for foundations and piling but Aspin is the only company delivering an innovative micro piling solution that overcomes the issues in hard rock ground areas to provide high integrity support for heavyweight structures such as OLE masts.
It’s also a highly sustainable means of completing works thanks to a deceptively simple combination of equipment that gives transportation ease of access and handling for track teams.
Leading international supplier of consulting and infrastructure support services Amey called in the Aspin team to provide a piling solution to hard ground on Network Rail’s Greater West Electrification Project (GWEP), Route Section 6D. The 1.5 miles of track had a four week blockade, during which time Aspin delivered 58 foundations as part of the OLE works and plans are already in place for similar projects.
The Aspin team has a unique solution that overcomes the issues in hard rock areas where high strength piles are needed for structures such as OLE masts but traditional CHS driven and augered concrete piles are not an option.
Costly and time-consuming works to create piling into rock of five-plus metres for embedded and heavy structures such as OLE masts can be avoided. It also means that the system is minimally invasive and sustainable, being relatively lightweight and requiring no specialist transportation or track access.
Tested and proven, Aspin’s solution uses four micro piles that support a steel grillage in a 950mm x 950mm square formation to provide four holes for hollow bars and six holes for the bolts for the OLE mast.
Each pile has a 150mm diameter bored hole filled with grout and a 76mm diameter hollow steel threaded bar in the centre, with the bore formed by a top drive hammer driving the steel bar into the rock using a sacrificial drill bit. Grout is later pumped into the hollow bar for added strength and the trial pit spoil is excavated and replaced with concrete for lateral support to the top of the piles.
In works for Amey and Network Rail on a 1.5 mile track section between Swindon and Bristol, the Aspin micro piling solution was used during a four week blockade, creating high strength OLE piles at 58 locations.
Up to three foundations were completed during a 10 hour possession, with minimal environmental impact. The equipment needed is relatively lightweight so no additional specialist transportation, manpower or track access is needed – just a track trailer with air compressor and equipment.
Vaseem Ali, Amey Construction Manager said: “The micro piles were a cost effective solution to the problem of installing foundations in rock which is notoriously difficult, adding to the complexity of track works. We’re pleased with the Aspin work which was all within the timescale and how the team worked with us to resolve the issues that crop up during any programme.”
Jimmy (James) Temperley, Aspin Project Supervisor added: “Our innovative micro piling solutions are proven to overcome the problems of foundation piling for OLE and works in rocky ground, providing high performance support and sustainable, safe, project delivery.”
- Foundations & Piling