The proposed structure is a mixed use building in central London, mostly framed in steel, comprising of a basement, ground, 8 upper stories and roof with four of the storeys containing partial mezzanine floors.
The Building will contain 270,000 m2 of offices with one-acre floorplates with each floor having its own roof terrace. The scheme will also include retail space, a doctor’s surgery, public roof space, café and 21 affordable apartments.
The site is that of the old Royal Mail Western Central District Office located at 21-31 New Oxford Street, London. The site is bound by New Oxford street to the north, Museum Street to the west and High Holborn to the South.
The proposed works for the office include the construction of new steel-framed floors of concrete on metal decking above an existing reinforced concrete raft foundation. Parts of three floors of the original building are being retained with the new floors connecting to them. Parts of the retained structure require strengthening and some retained beams are to be made shallower.
The stability of the building is provided by a new large main core, framed in steel and two new smaller cores constructed using reinforced concrete. Maintaining the temporary stability of the retain floors during the redevelopment is essential, it is anticipated that the main core will be the first part of steelwork to be erected and that demolition of the existing structure will overlap with the steelwork erection. The stability of the steelwork frame is provided by a combination of reinforced concrete core walls and permanent steel vertical bracing elements. Horizontal forces are transferred to the stability elements by horizontal diaphragm action of the floor and roof decking.
