Architect and Builder June 2020 | Page 40

This Spread: Hotel Images reinforcing dowelled in afterwards to connect the cantilevered slabs. The 23m wide sensually curved porte-cochère over the entrance vestibule is a marvel of structural ingenuity, cantilevering 12m from the building from cylindrical steel stays which seem impossibly flat to hold up the combined weight of the 18mm thick glazing and steel joists. Stepping the perimeter joists and cantilevering the glass sheets has created a visually very thin and ethereal feel to the porte-cochère. Engineering The 12-storey One on Whiteley Structure at Melrose Arch consists of eight suspended slabs for residential and hotel use above a ground floor retail level with four levels of basement below that. The basement parking structure was constructed using thin post-tensioned slabs whereas the residential slabs made use of bonded posttensioned cables. The structure is split into two portions separating the hotel and residential floor plates running east to west. Due to the varying depths of residual granite rock, the foundation method chosen was a combination of conventional pad footings and piles. Single large diameter piles ranging from 600mm to 1,800mm were chosen, firstly to reduce the risk of localised variability but secondly, mainly to achieve cost optimisation. Pile caps were also eliminated and the columns sprung directly out of the pile. Special column cages were dropped into the pile to achieve the desired stress transition. The installation of the larger diameter piles posed quite a test for the piling contractor with ground 40 One on Whiteley