SCREW PILE foundations have been used for the first time for the installation of cantilevered variable message sign (VMS) gantries in a pilot project for the Highways Agency, it was revealed this week.
Contractor Nuttall installed foundations for the gantry at junction 12 of the M11 using steel screw piles designed and supplied by Screwfast.
Screw piles are similar to augers. Grout can be injected through the stem to rm up ground around the ights (NCE 15 December 2005).
When the foundations are no longer needed, the piles can be unscrewed and removed.
Installation took just four days, but this could be shortened to 36 hours with longer lane possessions, said the Agency.
Driven piles with a capping beam would have typically have taken 10 days.
The trial paves the way for the wider use of screw foundations for highly loaded structures across the trunk road network, said Screwfast chairman Peter Dunn.
'The gantries are big and subject to large wind forces, imposing signicant torsional loads on the foundations, ' said Dunn. Dunn said the Agency had accepted screw piles for smaller structures but required demonstration of the piles for large structures before approving their use across the network.