Project: Shotts Line Over Bridge 626, Shotts, Scotland.
Principal Contractor: BAM Nuttall
Scope of Works: Van Elle to carry out Installation of 20no 323mm Super Jaws Drilled Piles to a design depth of 20m
Plant and Equipment utilised: Klemm 709 and Klemm 708 in 5m mast height configuration, and 2no Numa T280 Super Jaws Overburden Drill Systems to install 324mm permanent casing.
The required works were carried out during night shift possessions due to the nature of the works, with a piling rig positioned either side of the existing railway line. The existing road bridge which is the main artery into the town of Shotts remained open throughout whilst the work was carried out but was closed temporarily to allow the loading out of equipment and materials by merlow crane from the bridge above to the work areas below. Adverse Weather conditions throughout the project meant the working platforms were under water for the majority of the time that the piling works were carried out, making installation of the …no piles very difficult. All pile positions were permanently cased off to rock head using two Numa Super Jaws T280 drill systems through varying overburden predominantly consisting of made ground over layered clay and mudstone followed by a very hard limestone some 30m below working platform level. All cased pile positions were then re drilled using a 279mm Button Bit fitted into a 8” Numa DTH Hammer to form the required design rock socket to accommodate the imposed load. This element of the project had to be sequenced accordingly to prevent possible migration of air into previously drilled pile positions. Following completion of the rock socket installation, steel reinforcement to the required design specification was installed into each pile location prior to grouting. A site batched grout to the required design specification was then pumped from the toe of the pile, via tremie delivery hose passed down through the centre of the steel reinforcement cage. This ensured that any water within the anulus of the pile was purged form the pile. The project was completed within programme duration.