Access the site was only possible via an external stairway and in through double doors at lower ground floor level. A demountable drilling rig was used which was broken down into the component parts and manually transported to the position of the borehole where the rig was reassembled. Due to the limited headroom available at the borehole location the ceiling above was partially removed to enable the drilling rig to operate. As the works were completed internally a suitable fume extraction unit and lighting was used to provide an appropriate working environment for the drilling crew.
In addition to the limited access issues, the works were also required to consider the implications of ground vibration that may affect the security system protecting artwork stored in the buildings above and adjacent to the investigation area. Strict working times were also allocated to the investigation works to prevent disturbance of the parties using the offices above the investigation area.
The works were planned and fully supervised by an experienced geotechnical engineer from ASL. On completion a detailed interpretative geotechnical report was provided to the Structural Engineer.