The First Metropole Hotel Extension
The Metropole Hotel tower, on the corner of Edgware Road and Harrow Road, was built by Siefert in the early 1970s. It has bedrooms to the 25th floor and a plant room above. A central service area has a bank of four lifts. In the 1980s the hotel began improving the fittings and facilities. At this period the land was rather away from all development, on the edge if run-down industrial buildings and therefore site was cheap. Years later land prices were to sky rocket.
In 1989, in a more optimistic economic atmosphere. it was decided to extend the hotel, converting it into an international conference centre of the highest quality, very near to Marble Arch and convenient for all forms of transport. The total contract was for £50 million. The building contract alone was for £32 million and the rest was for fittings and furnishings. There would be an extra 200 bedrooms with higher quality fittings and facilities (Bird's eye Maple instead of painted surfaces; marble in place of ceramics; etc.); a leisure area and swimming pool; conference rooms and a very large Function Room completely free of pillars. The client wished to build right up to the site boundaries. As these included Edgware Road and Praed Street, both full of traffic day and night, there would be difficulties in the building.
To add to this, the plan was to dig down three storeys and place a Function room, completely free of pillars, at the very bottom. Finally, the Metropolitan Railway, which had been built along the centre of Praed Street in 1863 by cut and cover, ran only a few feet from the hotel perimeter and would be higher than the Function Room. Trains running every few minutes would drown out the functions. There were enough problems here to give any civil engineer sleepless nights.
The Design Solution
It was decided that the Extension would be a completely separate building about 5 metres from the old Siefert Tower and connected to it at Ground Floor, at Mezzanine and at each bedroom level. This would all be part of the fire escape and hotel services facilities.
The new building would have to be excavated to lower than the original piling supporting the 25 storey building, so care and ingenuity would be called for if the tower was not to tilt, or even fall down.
It was decided to build the bottom six floors of the structure in steel, with nine storeys of hotel bedrooms in reinforced concrete above. The section shows a reinforced concrete diaphragm wall all round the building and a concrete raft resting on 157 deep concrete piles. This construction was too complicated to discuss here but was a pleasure to watch as it developed in carefully thought out stages. The logical planning was a delight.
The reinforced concrete diaphragm wall is shown as the white space all round the site.