The foundations division is working with main contractor Sir Robert McAlpine on a number of construction elements, which are being monitored for ground movement by engineers from GEO-Instruments. These include constructing a 32m long, 600mm diameter secant piled wall to provide an extension to the rear of the existing hotel and, internally, 104No 300mm restricted access bearing mini piles to new cores to support a variety of other pits and walls.

There are also 106No plunge circular hollow section mini piles to underpin 26 existing columns to create a new deeper double-storey basement beneath the existing structure.

Meanwhile, GEO-Instruments have installed a system of manually monitored inclinometers within the secant wall to a depth of 16m which will monitor the deformation of the wall as excavation works commence, along with a settlement stud monitoring system measuring the movement of the site's extremities. 

Twice weekly surveying of both systems is occurring and prisms will also be installed along the top of the capping beam on the wall, which will provide more information to be added into the existing surveys.

"It's great to be bringing our expertise to such a prestigious project. We're really looking forward to seeing the finished building," said Eddie Donaghy, Keller construction manager.