Scraping the Sky: ‘The Scalpel’
- June 1, 2017
- Posted by: Shelby Buchanan
- Category: Architecture, Building, Central London, Commercial, Construction, Construction News, Development, General Construction, London, News, Sky, Steel, Structural Steels
52 Lime Street, London or “The Scalpel” is a new commercial development situated in London’s Square Mile. Featuring a dramatic architectural shape with asymmetric facets and a pointed attic roof structure, 52 Lime Street will surely make a lasting mark on London’s skyline when it is completed later this year. Joining a cluster of other prestigious high-rise buildings in the square mile, the project will offer 36,966m2 of internal floor area over 35 office floors, retail space and restaurant areas.
Steel-framed structures are often favoured over more traditional building methods such as concrete high-rise, as pre-fabricated steel can be installed rapidly on site making it less disruptive to the local area, an important consideration for a project in central London.
The building’s unique design means the northern elevation is at an incline, enabling the floor area to decrease from over 1500m2 to 614m2 on the 35th floor.
In an effort to maximise floor space, the architect Kohn Pedersen Fox has opted for a steel frame as it allows for more open floors as there is less of a need for structural columns. In fact, up to floor 21 the building has only one row of internal columns and floor 24 and above contain no internal columns.
They also took the unusual choice of offsetting the concrete core that contains the three banks of lifts. Due to the 3 banks of lifts 1 for the lower levels, 1 for the mid-levels and one for the upper-levels, this means that space is not wasted towards the top of the building as only one bank of lifts services the top floors as opposed to having to accommodate 3 separate lift shafts.
In addition to these space-saving measures, viscous dampers have been utilised in the north elevation steelwork to dissipate energy generated by wind and therefore reduce uncomfortable side to side acceleration. Whilst being cheaper they also take up less space than the more commonly used Tuned Mass Dampers, which are essentially giant pendulums that achieve the same result as viscous dampers.
Structural steelworks have given architects a great amount of freedom due to its light weight in comparison to reinforced concrete it is 60% lighter, thus considerable savings can be achieved as smaller foundations can be used for a steel frame building compared to concrete frame buildings. It is no surprise then that market share for steel in the commercial building sector has consistently hovered around 65%-70% and also continues to be utilized more and more in composite construction techniques.