All Foundations were contracted to provide foundation piles to support a 7.5m deep sub-basement extension to the former Royal Sun Alliance Headquarters, Selwyn House, next to Green Park in London which is now a single residence.
Due to the location of the building Ian Cull, our Senior Estimator for the Southern division of All Foundations, visited the site to determine the available access and concluded that Restricted Access piling would be required due to the very tight restrictions both on the site and in the surrounding area.
The challenge was to design and install piles to support compressive loads of between 300-700KN and tension loads of 325KN. The ground conditions being water bearing sand and gravel to a depth of 11.0m, overlying London Clay. The working area being 12m x 10m, set 3.0m below pavement level. The site being in a high security area adjacent to St James’ Palace and Clarence House, with a very narrow access road surrounding the building.