The thirteen-storey Six Pancras Square was designed by French architect Wilmotte & Associés, and is now home to Google. Clad in terracotta, the landmark building features a full-height central atrium, roof gardens and two basement levels.
Commercial office building as part of the huge masterplan for Pancras Square in North London
The new building is part of the prestigious Pancras Square development in King’s Cross, located on the site of former gasworks, posing significant ground engineering problems for us to solve. Remediation works included the removal of a former gas holder, while ensuring that the piled perimeter wall along Pancras Road was completely watertight to prevent any risk of contamination. This wall was constructed from secant piles, sized to limit deflections during an unusually long ‘temporary’ state. Where the wall slices through the gas holder, piles were further waterproofed using injection grouting, with a cavity in front to capture any seepage.
The high-pressure Thames Water Ring Main runs under one corner of the site, so we carried out detailed geotechnical analysis, modelling the effects of site clearance, piling work and construction, to demonstrate to Thames Water that the impact of the works was within acceptable limits.
The building itself features a reinforced concrete frame to upper ground floor level, the remainder constructed from steel and designed as column free, delivering efficient and flexible workspaces with spans in excess of 13 m.
The structural grid features spans of up to 13.5 m, constructed with 130 mm concrete floor slabs poured onto profiled metal deck, working compositely with 630 mm-deep cellular steel beams, specified to keep the structure as lightweight as possible.
We modelled the structure to ensure vibrations were within acceptable limits. The structure has also been engineered to be as flexible as possible, with ‘soft spots’ that can be opened up to insert new staircases, while the atrium can be partly infilled to provide additional floor space without the requirement of strengthening works.