The Westbury Hotel sits in the opulent area off Bond Street in London’s Mayfair. Originally completed in 1955, the upgraded hotel will have two new levels of basement, along with a new 8th floor. There are rumours that it will be sold on completion for over one billion pounds! The construction substantially increases the footprint of the building, whilst actually reducing the number of hotel bedrooms.
The challenge is to take an existing structure, support this existing structure, then build two new levels of basement underneath while temporary supporting seven existing floors. There are new extensions each floor and a totally new top floor. The challenge for the RC detailing is to work with the site team to deliver accurate drawings for the rebar within the constraints of the structure. We needed to deliver rc detailing of each element, which is adapted to work with each phase in construction. Providing accurate information within the constraints of an existing footprint is always challenging, as original survey information is an estimate.
The building was supported in the temporary state. We provided the capping beam to sit onto of the new pile arrangement, which enabled excavation of the new basement to begin. We detailed plunge columns that went down into the existing ground in the temporary state. Once excavated, the B2 basement was then built using our rc detailed drawings for the rebar sizing and layouts. We then provided details for the 3 storey liner walls and the B1 slab. We provided the concrete columns for the permanent state. Our details were tweaked to work with the existing structure interface, so what looks like a cut and carve project, will end up as a seamless extended modern hotel.