Area:  0.1 Hectares

Development: Residential Renovation

Services: Geotechnical Investigation

ASL operated as geotechnical consultants for this residential redevelopment site located on the lower ground floor and ground floor of a six storey terrace building in central London.  A ground investigation was undertaken to establish the ground conditions and geotechnical properties at the site to enable pile design parameters to be established for the proposed development.

The proposed residential redevelopment comprises the renovation of the ground and lower ground floor of the existing structure together with the construction of a single storey extension to the lower ground floor.  As part of the development works a substantial amount of the existing load bearing walls are to be removed together with the installation of new reinforced concrete transfer slabs and columns which are to be supported on piled foundations with very strict tolerances on settlement of the overall structure.

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.