Great Glass Elevator is a glass lift which is at the heart of the project extending eight storeys from the basement to a roof terrace that has created a world first in a residential property.
We think this project took glass engineering and construction to new heights, literally and figuratively, and as far as we are aware it is the tallest self-supporting annealed glass structure in the world
According to the Bath-based consultant, the first stacked load bearing glass walls began to emerge in the 1990s, such as the Glass Cube Reading Room at the Arab Urban Development Institute in Riyadh, Saudi Arabia, which was designed by Dewhurst Macfarlane & Partners. Initially, Malishev took on and developed the principle of vertically stacked load bearing glass further at the Bolton’s Place residential development in London, which was completed in 2006 and included a 20-metre high structure. For the Knightsbridge project, these principles would be extended even further. “From the early design meetings the architects wanted to produce a ‘wow’ effect from this central feature in the house which would combine minimal design and maximum transparency,” says Mr Malishev.
For all the design and construction team, producing such a ground-breaking scheme was to prove a challenging task. The scheme features an experienced array of consultants and contractors with experience in high-end residential projects, with TFA producing the design, Malishev working on the glazing for the lift and Walter Lilly brought on board as the main contractor. Work has only just been completed but initially began in August 2011 with the reconfiguration of the internal space to create space for the lift. This also necessitated a major excavation project. The basement work alone took around 11 months to complete and the centre-piece glass lift was two years in construction. Finding a specialist sub-contractor willing to take on the lift element was difficult due to the challenging work. Mr Malishev adds: “Many subcontractors were simply afraid of this contract and refused to tender altogether, regardless of the costs.”
Only two companies were willing to put in bids. AXIS Elevators won out with the glass supplied by UK Glass. Installation of the glass began in March 2015 and the panels were lifted using hoists and an overhead gantry then down through the oculus of the openable roof light. A hydraulic ram lift was used as a working platform to facilitate the process of installation. Despite a very tight working space, no glass panels were damaged during installation process. The last panel of glass was installed on March 29 2016 and the lift was finally commissioned in January 2017. The glass structure comprises a curved laminated glass cylinder in diameter with a cantilevered steel staircase wrapped around the outside. The enclosure size of the lift has been restricted to 1.4 metres and this is dictated by a very tight floor plate arrangement.
There is also an external door and an internal lift door, which are both made from glass. Due to the circular structure, this was also a challenge. It’s about the tightest radius you can get. All the glass pivots so you can get access to clean the panels.” There are three sheets of curved glass for the exterior of the lift shaft on each floor. “It’s a parallelogram shape and the glass is tied in at intermediate levels,” explains Mr Edwards. The glass shaft of the lift is split at each floor level with a helical steel handrail, which acts as the splice joint between the top and bottom glass panels as well as providing lateral restraint. The top of the lift shaft is capped by static and openable semi-static roof lights and on each landing-level for the lift.
A series of high precision rollers and rails were used on inner and outer perimeter rings to support the sliding roof light. The roof light is comprised of a crescent shape walk on double glazed units, spanning one metre between the inner and outer perimeter ring support.” The sliding floor unit moves using a spur pinion gear with a planetary-type motor and supporting V-shaped wheels with the self-supporting glass cylinder sitting on top. This makes this mechanism truly unique in this kind of application. We were responsible for specifying the system and worked closely with the system manufacturer to advise our steel and glass fabricator with the best available options as well as the critical tolerances required.”