Moving to and around site was a high priority for Pennine Vibropiling when designing the latest addition to its fleet, pictured here just four days old on a job in south east London last month.
Pennine set out to develop a compact mast mounted vibro rig for top feed stone columns and vibro concrete column piles that could be transported on a low loader, without police escort, and which could be in production within an hour of arrival on site. To facilitate this the rig is fitted with both onboard fuel tank and air compressor, avoiding the need to co- ordinate their arrival on site from local suppliers at the start of a contract.
Mounting the poker on a mast improves on-site manoeuvrability compared to crane-suspended vibro equipment, and greatly increases the ability to instrument the construction process. For vibro work the company now measures hydraulic pressure, depth and time, while for vibro concrete column applications concrete pressure is also measured during placement.
Pennine southern area manager Derek Taylor says instrumenting the process provides valuable internal checks as 'we want to be sure we are providing a reasonable product'. It also provides useful measures to correlate against production performance and estimating quantities.
The new rig is officially called Stratacaster 1020, but in line with the company's habit of naming its equipment after characters in Thunderbirds, is also known as Tin Tin . She will be working hard for most of July at a Bellway Homes site in Borough, south east London, installing 621, 500kN capacity load bearing vibro concrete column piles.
Installation is through fill overlying river gravel, and requires penetrating 0.5m into the gravel. Column depth is typically about 4.5m, but in places where old basements have been removed, depths to 8m will be needed. Tin Tin is equipped with a 12m mast, allowing maximum penetration to about 10m depth. Production rates of 150 piles per week should be achieved on the London contract.