Comment: Engineering a giant in the heart of The City

But the engineering of tall buildings is no easy feat. The higher these structures reach into the sky, the harder they must work against physics. Compared with low- and mid-rise buildings on the same footprint, they must also transport more people to their desks or meeting spaces, keep more floor area at comfortable temperatures, and tread lightly on the planet whilst doing so. 

While these factors make for a challenging design and construction process, they also encourage efficient and creative solutions. Within the City of London, robust constraints on  planning, combined with the evolving London Plan, drive improvements in sustainability, safety and social value, meaning proposed tall buildings in the city are only given planning consent if they are of an exceptionally high standard.

8 Bishopsgate – a 50-storey office tower in the Eastern cluster of tall buildings - shows these principles in practice. With its stacked block design, the 204-metre-tall building opened in 2023. The WilkinsonEyre designed building can accommodate over 5,000 people across 47 office levels, alongside amenities for its users, paired with The Lookout, a public viewing gallery at Level 50.

More from Civil & Structural

It serves as a case study to demonstrate the opportunities tall buildings can present, having been designed and constructed with sustainability and safety at its heart, all while maintaining the iconic architecture and high quality design expected of tall buildings in London.

A project timeline

One thing not always obvious from the outside is just how complex and interconnected buildings are. The project team need to move from a client brief into a realisable design though an increasingly detailed series of design and construction gateways, starting some time prior to a planning submission. Throughout the design process, every element of the proposed building will be debated, thought about, assessed for value and impact, ultimately being modelled and checked for coordination between and across disciplines. At the centre of this is the architect, whose role it is to help steward and mediate across often competing and opposing discipline drivers. 

A project like this is a unique collection of parts, assembled together in a way that can be built safely, quickly and to a high quality. 

There are things that can catch us out – for example the way that buildings move and deflect in use. Mother nature exerts forces on buildings when the wind blows – sometimes unpredictably – and the building’s movement in response to this must be designed not to cause discomfort for occupiers. Understanding and predicting the impact of this requires special care and attention from a collective of clever people: no-one would thank the engineer whose design failed to account for such things. 

8 Bishopsgate took a total of ten years to move from the architect’s sketch at feasibility stage through to a completed and occupied building: buildings of this scale are a monumental team effort. 

Sustainability at its core

In addition to the London Plan’s sustainability requirements, building occupants themselves increasingly demand robust sustainability credentials from the space they occupy. Since the project inception in 2013, 8 Bishopsgate had sustainability front and centre, allowing it to be become the tallest building to achieve BREEAM outstanding in the country, while also boasting an EPC A rating. This evidences a design that takes energy performance seriously – but what of material use and embodied carbon? 

On that measure too, the building performs well. Its as-built embodied carbon assessment shows a construction phase carbon impact below GLA ‘current’ benchmark guidance applicable to low and mid-rise buildings. That this was achieved in a building whose design was carried out before embodied carbon became a better understood assessment and accounting tool, gives hope that future buildings will be able to achieve lower carbon outcomes when the collective brainpower of the construction industry and its supply chain is applied to the challenge. 

To be clear, buildings of all shapes and sizes must do more to use (much) less in the very near future.

In many cases this will need us to reuse and adapt the buildings we already have: giving them a new lease of life as we seek to make them ready for the future. But this does not mean that we cannot or should not build tall where there are identified needs: we should build mindfully, and with care, using the lowest carbon solutions that we can.

Cities of the future

Engineering buildings that are tall just for the purpose of vanity is no longer enough. Future buildings must be made with occupant safety and the planet in mind, both during construction and while in use. As cities grow, and demand on space becomes starker, the industry has a huge responsibility to provide buildings that serve the city’s environment and residents. 

We must rise to this opportunity, taking learnings from buildings like 8 Bishopsgate to push ourselves to the limits of creativity and design. There are exciting proposals on the drawing board for the next generation of tall buildings in the City – it is important to us all that they are able to meet this challenge.

Chris Edgington, building engineer, Arup