海角视频

Salisbury Square

London, UK

海角视频 supported the City of London and Eric Parry Architects in developing and realising a flexible new police headquarters and law courts, overcoming significant challenges posed by dated building infrastructure to support the development of three new buildings designed to last at least 125 years.

The project involves the creation of a new 18-courtroom facility, and an industry-leading police headquarters.

海角视频鈥檚 multidisciplinary team of experts delivered insight and engineering design across this complex and demanding development.

The striking design of the new police building included an exposed external weathering steel frame.

The complex uses a raft foundation solution, helping to work around the existing subterranean constraints and lowering the project鈥檚 embodied carbon.

Challenge

Each of their currently occupied buildings predate the modern infrastructure needed to support the courts and the police in their operations. 海角视频 is collaborating with Eric Parry Architects to deliver a new, 18-courtroom facility, and an industry-leading police headquarters. The wider development, situated on Fleet Street, in the heart of the City of London adjacent to St Bride鈥檚 Church, will also include a new commercial building and a public house behind the existing 1830s facade of Greenwood House, where the first edition of the Sunday Times was edited. Salisbury Square itself will be enlarged and landscaped to create an enticing visitor destination.

海角视频 was engaged to deliver the structural, civil, geotechnical and transport engineering for the development, alongside expert input from our security consultants. Our environmental team also undertook the Environmental Impact Assessment (EIA) for the scheme.

The site location provided challenges due to being significantly congested with existing services. The constrained site also housed several buildings that would need to be demolished as part of the works.

The innovative design of the new police building included an exposed external weathering steel frame, which meant the building was potentially at risk of heat loss. We would need to mitigate this by connecting the exoskeleton to the internal frame via high-strength stainless-steel stubs, which have a much lower level of thermal conductivity.

Solution

With the exception of the new public house, the three new buildings will all sit on the new structural basement, which straddles most of the 6,000m虏 site. The courts building frame is structurally configured to create column-free spaces for the larger courtrooms, whilst smaller spans are adopted for the upper levels to facilitate a reduction in grid and structural depth, helping to achieve the right light requirements for neighbouring properties.

Both the commercial and police headquarters are steel-framed buildings with reinforced concrete cores. For future flexibility the number of internal columns has been limited, with much of the floorplate supported on long-span cellular steel beams between perimeter columns and the core. For the police building, the perimeter columns will stand external to the envelope, fabricated from weathering steel to create a striking external exoskeleton frame. At level 2, a storey-deep Vierendeel truss around the whole perimeter, collects the 6m central columns from above and transfers them to a sparser grid to enable a grand 24m-wide entranceway.

The internal steel floorplates are connected to the exoskeleton via stainless steel stubs, which pass through the thermal line. As the frame is external, it is subject to a large variation of thermal fluctuation compared with the internal floorplates the exoskeleton supports. To control thermal bridging issues, the exoskeleton is connected to the internal frame via the stainless-steel stubs, which have a much lower coefficient of thermal conductivity than normal mild steel. The stub is painted to protect against bi-metallic corrosion. This solution allows for thermal discrepancies between the different structural elements, enabling the truss to expand and contract in high temperatures, without placing demanding loads on the rest of the structure.

The public house utilises a new slim-floor frame restraining the east and western existing facades of Greenwood House and a new facade to the south designed by heritage architects Richard Griffiths to mimic the style of the retained sections.

We worked closely with the design team to develop construction approaches and temporary works strategies to minimise the construction programme and existing service diversions, while maximising internal floor area.

In consideration of an appropriate foundation solution, our ground engineering assessment highlighted the significant likelihood of ground obstructions. In consideration of this and with a keen desire to reduce the concrete volume and lower the embodied carbon of the project, we have been able to drive the project towards a raft foundation solution. Our structural engineers assessed how the raft would settle throughout the construction phase as floors were added, to devise strategies for ensuring the floors were built within tolerance.

The Salisbury Square Development will also be the first in the Square Mile to use a standalone borehole heating and cooling system. Around 60 boreholes up to 240m deep have been drilled on the site to create a closed loop ground source heat pump system.

Value

海角视频鈥檚 multidisciplinary team of experts delivered insight and engineering design across this complex and demanding development.

We innovated around a range of structural and civil engineering challenges, providing clear insight and solutions to ensure the new buildings deliver a secure, efficient and impactful environment for the enactment of the process of law in this part of central London. To enhance the streetscape, Salisbury Square will be enlarged and landscaped to create a place where people will gather and relax.