Published: 09 November 2017
Craig Irvine describes his work on a project to refurbish the Curtis Green Building on Victoria Embankment in London, as the new headquarters for the Metropolitan Police Service. Scotland Yard is shortlisted for The Structural Awards 2017.
The project to create a new home for Scotland Yard saw Arup work with architects AHMM to deliver high quality, contemporary offices by adding an extra floor to the Curtis Green Building, extending the floor plate and reducing the density of columns – while respecting the grain of the original architecture and structure.
There is also a challenge to working with existing structures that can be especially rewarding to the design team – combining the best of modern methods with structures that have stood the test of time. I’m proud to say that we managed to retain 88% of the original structure.
The most significant challenge on the project was the lack of recorded information about the existing structure. This was a problem, as the key architectural driver was to create an open, transparent environment by removing many internal walls – and much of the building’s existing stability system in the process.
We were also adding a floor, which meant adding weight to the structure and foundations which they weren’t designed for. With very little recorded information on how the foundations worked, complicated by proximity to the River Thames, this was a significant factor.
We therefore carried out a thorough structural survey to further our understanding of the building, including a full 3d point cloud model of the building geometry, supplemented by a range of further tests and surveys.
We concluded the best approach was to design the new extension to support not only the new build but also the existing structure and the façade system. This work required significant co-ordination with the architect and façade engineer and early programme studies with the contractor. A full finite element analysis model of the façade was developed which enabled evaluation of the structural behaviour of the building interacting with the different proposed options. This approach also allowed us to shave three months off the projected construction time.
It was also very difficult to satisfy a key conflict in the design philosophy: the Metropolitan Police Service wanted a transparent building to align with modern values, but that was also highly secure: that meant that the entrance pavilion was designed as a glass box that also needed to provide an effective security barrier. The full design team worked in very close collaboration to reconcile this seemingly irreconcilable desire, carrying out a lot of design work and a lot of testing.
This work focused on creating simulations of the glass performance and verifying them in laboratory tests, including full scale blast testing. Our design is understood to be the first application of its kind to use curved glass to address such stringent design parameters.
There are many individual transferable achievements from this project that could be applied to other renovation projects. Modern working requirements tend to favour large open spaces with generous floor to ceiling heights. To achieve this we developed a solution where the supporting beam would fix from above in the raised floor zone - allowing steel to be installed without propping. This accelerated the programme by freeing up large areas of the site which propping would have made inaccessible.
There has been a fantastic response from the public to Scotland Yard as an example of a public building delivered on time and budget. Feedback suggests the building has transformed the Met’s working habits, promoting greater collaborative focus.
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