GEA were commissioned to undertake a desk study and two phases of site investigation for a site in Vauxhall, located on a documented scour feature, originally discovered during piling for the former Market Towers in the 1970s.
The former Market Towers comprised two connected towers of 16-storeys and 21-storeys with a two-storey podium and a single level of basement, supported on 600 mm and 750 mm diameter piles, which extended roughly 25 m below ground level.
Planning permission was granted for the proposed scheme by the London Borough of Wandsworth, ahead of GEA’s instruction. The redevelopment of the site comprised demolition of Market Towers and the subsequent construction of two new towers of 43-storeys and 56-storeys, together with a low podium structure and up to three levels of basement.
GEA’s investigations were limited due to the continued presence of Market Towers and the presence of two Victorian sewers. Phase One of the site investigation works took place in Spring 2014, in conjunction with demolition works and comprised six rotary boreholes to depths of between 65 m and 75 m and five cable percussion boreholes advanced to a maximum depth of 35 m, drilled around the perimeter of the building footprint of Market Towers. Self-boring pressuremeter testing was undertaken in two of the boreholes to supplement standard in-situ testing.
Phase Two was undertaken in Winter 2014 and was limited to the eastern part of the site. Phase Two comprised three pre-cored cable percussive boreholes through predominantly granular soils, followed on with Geo-Bore S wireline rotary techniques, to depths of 50 m. A series of vibrating wire piezometers was installed within each of the boreholes on completion, in order to order to determine pore water pressures.
Given the proposed high loadings for the new towers, deep piled foundations were required and a diaphragm wall provides basement support.Contact Us