Site Investigation, Ground Movement & Asset Impact Assessment, Foundation Reuse

CGL was instructed by Structural Engineers, Heyne Tillett Steel (HTS) to undertake a site investigation and geotechnical analysis at One Berkeley Street in the City of Westminster. The proposed redevelopment comprised a series of existing building reconfigurations including the demolition of all structures above the 7th floor across the entire building footprint, with two new steel framed stories being constructed above the 7th floor of the retained RC frame; demolition of an existing three storey structure which protruded into Dover Yard and a new six storey structure constructed in its place; demolition of the annex building to basement level and a three storey building constructed in its place. The aim being to retain and reuse the existing basement and sub-basement raft structure for the proposed development.

The analysis at One Berkeley Street was pragmatically streamlined to undertake preliminary building damage assessments and asset impact assessments using CGL in-house borehole data and readily available British Geological Survey (BGS) data to meet a tight programme and to meet planning application deadlines. A site investigation (SI) was undertaken simultaneously with the analysis comprising several deep boreholes, shallow window samples and trial pits confirmed the preliminary ground model and structural details within the assessments. The findings of the SI fed into the analysis and validated the ground model used.

This sequence of preliminary analysis informed by CGL’s vast London ground knowledge, and then informed by a site-specific SI to validate the assumptions and model was extremely successful, reducing the project programme by several weeks, and allowed a tight planning programme in Westminster City Council to be met effectively.