Van Elle’s expertise put to the test by height restrictions on the Tannery Bridge

Van Elle Ltd, one of the leading geotechnical, piling and foundation engineering contractors in the UK have recently received the contract and have started on site on the Tannery Bridge replacement in Downton, Wiltshire.

The bridge that lies in the heart of the village and crosses the river Avon had reached the end of its economic viability, and a replacement had been sought.

Wiltshire County Council awarded this crucial project to Alun Griffiths Contractors Ltd who in turn drafted in Van Elle to install the piles.

The project comprised of demolishing the existing temporary bridges for the pedestrian footpaths and the single carriageway followed by a reconstruction of a brand new two lane bridge.

Van Elle’s expertise was put to the test by a restricted working height of four metres for half of the foundations which were under the temporary structure now assigned to carry traffic.

The initial design for the foundations was not particularly advanced at the enquiry stage, yet the deconstruction and temporary works were in full swing. This design suggested 450mm diameter CFA piles, which proved to be impractical to install given the height constraint.

This is where Van Elle’s innovative approach came in with an in-house 350mm diameter CFA design, to address the access issues. This quickly received design approval, so using the Klemm 702 to install 68no piles to a depth of 12m Van Elle completed the job.

The scope of works required the temporary diversion of the river and extensive preparation works to turn the riverbed into a piling platform. Van Elle worked closely
with Alun Griffiths to get the highest site standards possible given the potential safety and environmental issues. These were due to working in the riverbed which caused access problems to the piling platform and
possible risks of water contamination from grout or diesel release. Van Elle’s high standards resulted in them scoring highly on a recent in-house health and safety audit report.