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Possibly the most famous prophet in history is Nostradamus. The French astrologer lived in the 16th century and wrote lengthy poetry, supposedly predicting things to come. Every year his cryptic verses are seized upon by journalists looking to fill column inches and mystics fearing the End Times. If Nostradamus penned something that hits reasonably close to major events, his esteem grows. If he misses, what does he care?
But there are businesses out there that actually have to predict the future. They have to guess how individuals and society will behave 5, 10 years into the future. They can look at behavioural trends, industry preferences, but ultimately, a lot can happen in 10 years. And the people making these predictions are in charge of hundreds of millions of pounds. Their decisions carve out the built environment… and sculpt the skylines of cities.
If they get the decisions they make right, they can make money, yes but more than that, they can spark new relationships, shape companies, and affect the work of tens of thousands. If you want to meet someone who truly has to predict the future, find someone who is asked to build a skyscraper.
A new silhouette on the skyline
22 Bishopsgate or Twenty-Two is the latest major addition to the London skyline. It takes its place among the Gherkin, the Cheesegrater and the Walkie-Talkie… but although at 278m it is the tallest building in the City of London, and the second tallest in Western Europe after the Shard, south of the River Thames. it doesn’t have an eccentric nickname (at least not yet). And there is a good reason for that. Whereas these other weird buildings are visually bizarre, Twenty-Two just isn’t.
Although Twenty-Two looks good from the outside… but the reason it is interesting isn’t how it appears from a distance. The reason Twenty-Two is sparking conversation is what it is going on, on the inside… What it is like to work, and to spend time in the building. And how its developers wholly predicted what people would need from a post-Covid office, up to 10 years before the pandemic. Which is how long it takes to build a skyscraper… and once it is with is, it is with us almost forever.
We will explore all of that, plus it’s unconventional birth from the unfinished remains of a skyscraper that made its own prediction for the future, a prediction that it lost, when the great recession hit.
The people who have to predict the future of the built environment come from diverse backgrounds and bring a range of skills. To make 22 Bishopsgate happen required a team of thousands. But this article episode will be built on foundations provided by a developer, a structural engineer, an architect, and a mechanical and electrical engineer.
First, we need to get a handle on the background of 22 Bishopsgate, and for that we need to meet our developer, Paul Hargreaves, the Construction Director for developer Lipton Rogers.
Back in 2012, Paul and Lipton Rogers had become aware of a stalled project in the City of London called Pinnacle.
“The previous Pinnacle project had a consortium of about 80 funders who were all putting money in to fund the development,” says Hargreaves. “And the project was haemorrhaging money. They needed to go back and ask the consortium for more money.”
The consortium said no, and the site was dormant for four years. The problem was that Pinnacle had been conceived in a different time, before the Global Financial Crisis. Design was completed in 2005 and foundation construction began in 2006. But the cruel calculus of the post-recession era made the building unviable.
Hargreaves continues, “Pinnacle was certainly a beautiful building, but a building of its time. buildings were getting names. And they were all very nice buildings, all lovely buildings, very sculptural. But the problem it had with the Pinnacle is that it was very much an art form. And to give you an idea, every single pane of glass in the Pinnacle was a different size. And that what comes with that is huge cost. And you know, there is no repetition at all.
“It also had quite a strange core, which meant there were transfers. So you literally had to go up a lift, transfer to another lift to get to the top of the building. And it meant the floor plates were very irregular.”
Generally not people really wanted from a practicality point of view. but again, undeniably a work of art.
“So when we started looking at it, we thought, well, we’ve got to find a much more economic way to make this building work,” says Hargreaves.
Conventional wisdom might have told Paul and Lipton Rogers to overreact to the changes of the financial crisis, to design a building for pure economy. Maximum floorspace, total financial efficiency. But they didn’t. They took a moment and called in more expertise. They contacted Despina Katsikakis, who works for the commercial real estate agent Cushman Wakefield.
Inspiration from down under
Katsikakis advised them to visit Australia to see what was happening there. The big banks and other companies were looking after their staff, putting people first. So there was a big research trip out to Australia to look at what was going on.
“They were building towers, but they were putting in lots of amenities. And this is where we got our vision for creating Twenty-Two and making it a vertical village,” says Hargreaves. “22 Bishopsgate could have 8000 people during a normal day in the building. Well, 8,000 people is a small town, not a village.
“And in a village or town, you would have your town hall, you might have your village green. But you’ll have you’ll have your local shop, you’ll have a restaurant, you’ll have, you know, food outlets, your coffee shop, you’ll have lots of amenities to serve the community. And that’s where we got the idea of designing a building that had lots of amenities to serve the occupants of the building. So the way that the building ended up being designed, lent itself to some spare spaces within the building that we felt that we could use and return to the occupants of the building.”
So not a knee-jerk, maximise rentable area, but make 22 Bishopsgate a comfortable place to be. With extra facilities that could be rented to companies or used by employees at will. A departure from prioritising aesthetics, but completely swerving away from a grim utilitarianism.
“We’re an affordable workspace. And then within there, we’ve put in spaces to be able to give presentations and lectures. So some bleacher seating, maker-spaces. You can have the best, immersive conferencing room or editing suites, stuff that tenants may want to use periodically, but might not want the outlay of creating a really great space in their offices where they only use it once a year.”
As well as this, on various floors they also built restaurants, viewing galleries, gyms, wellness centres… filling the structure with amenities, like they learned in Australia.
The winds of chance blew and the global pandemic emerged in early 2020. All of a sudden the destination office became the zeitgeist of what an office should be. Amenities, a desirable meeting location and rentable facilities became critical to businesses. But back in the early mid-2010s, to do all of this, required increasing the available area of the building by 30% compared to that which would have been offered by Pinnacle
It required immediate buy-in from the new consortium, ahead of planning permission being granted by the city. And on top of all this, the foundations for Pinnacle had already been built. Grinding and digging them out would be an incredible waste in a world growing ever more carbon conscious. Whatever followed would require impressive structural engineering.
Working with the foundations
Diego Padilla-Philipps joined WSP as a Structural Engineer in May 2014, and on the 21st of December, just before Christmas, he was presented the problem of how to balance the loads of a bigger building on an already-built foundation.
“And when we saw the magnitude of the column forces, we realised this is this is something big. The challenge was, how do we, how do we locate this new column forces into this existing capacity and find some transfer strategies, says Padilla-Philipps. “when we read the column forces, we thought this is something big. And it was actually a Christmas present. And then it changed the rest of my career forever.”
Padilla-Philipps spent the next five years working on the most challenging foundations of his career.
“that’s what we inherited, the call [AC1] was to be demolished, which was a small part of the existing structure and then the entire basement was to be retained as much as possible. Because when you when you have existing structures, what you tried to do is to reuse that capacity, that way you save on materials, time, possibly, but also in in in what is currently the most important factor which is carbon emissions.”
The less you build, the less carbon emissions you generate. The team had three stories of basement and the columns for Pinnacle. They were in positions that were not desirable for the new building.
“And the brief was to retain as much as we could, keep as much as we could. So not only from an engineering point of view, but also from an architectural point of view. How does the design team reuse the existing basement geometry to adapt to the new needs of a bigger and different building?”
The Pinnacle building had a unique spiral shape and had a perimeter diagrid – a framework of diagonally intersecting metal, concrete, or wooden beams that is used in the construction of buildings and roofs.
“So the perimeter columns had a special spacing, but also had very large capacity, because they were supporting the stability forces of the tower. So when you look at a plan, you had some capacity in the sense that it’s more concrete core, and then columns around the perimeter in an elliptical sort of shape, which was there because of the shape the Pinnacle. Ideally, we, we would need to locate the new columns where the existing ones were. So we could utilise all of our capacity. Now, the floor plate of 22 Bishopsgate, trying to optimise the use of the site was different, was bigger, was larger. So we had to coordinate with the architect where to place the new columns, so that they were as close as possible to the existing Pinnacle columns in the basement.”
And in some cases, this was possible. In some cases, this was a real challenge. So they had to create a transition level over several storeys.
“And the smoother that transition, the better it is, in terms of load transfer. So we used between levels three, and eight, to transition from the basement positions to the superstructure positions gradually in a way of inclining the columns in or out to meet them. And the reason why this was from level three and up is because I believe the intention for the ground floor was to have fully vertical columns.”
In structural engineering, inclined columns are the most efficient way to transfer a force from one point to another. But when you incline a column, you generate a horizontal force, which needs to go somewhere. So the columns have to be restrained at the bottom and top to stop them sliding.
“We’re generating mega horizontal forces somewhere. Now, the more inclined, the bigger the forces, the less inclined, the smaller forces. So if we incline between level three and level eight, that’s five levels than the forces are doable. And those horizontal forces have to travel through the existing floor plate into the elements, which resist the horizontal forces in the building, which in this case is the concrete core, where all the lifts are, all the services are.”
The core of any tall building is a really strong structure, providing lateral stability to the building, capable of holding those strong horizontal forces together. They travel into the core and down through the floor.
“In some cases, if the forces are too big, it goes through additional steel elements embedded within the slab, back into the core so that you’re holding that in place. And the same happens in the basement, whenever we have inclined columns, we are resisting these horizontal forces within the basement box with all the other elements. In some cases, we also needed bigger transfer structures, in some cases, it was impossible to just have inclined columns.
“And we have actually a big a deep beam, or a deep truss. And these mega transfers, what they do is they bring the forces from one position to where the capacity really is. And in some cases, these are hidden within the architecture.”
In the basement, they have a hidden beam that is nearly 4m deep.
“So it is basically a wall. And it’s hidden within a floor within a plant room so that is not seen. But there is a mega structural element there, transferring that. And one of the reasons the reasons why we couldn’t have an incline column or a column going through is because below that space, we had a turning table for the waste management lorries to go into the basement and rotate. And that was the only place where it could go to make sure that, that so in this case, for me, that was fascinating to understand, because it was the waste management strategy that was driving the structure.”
The relatively small footprint of a skyscraper and all of the disciplines that need to work together means that each team needs to work around the needs of their colleagues.
The living building
David Healy, a Mechanical and Electrical Engineer for WSP and is responsible, effectively, for the lungs and life of the building. Which is more effort than normal, given all of the amenities and features that the developers wanted.
“We call ourselves building services or MEP engineers, “M” being mechanical, and “E” being electrical and “P” being plumbing or public health. So I’ll sort of take it in order. On the mechanical side, we look to maintain comfortable conditions in the building. So that’s ventilating the spaces with fresh air, making sure that they’re heated and cooled. And what that means from a plant perspective is, generally on a building like this, we’ll have large chillers, generally in the basement, those will pump the chilled water around to all the occupied floors, so they can get their cooling from that system.
“And then we also need to get rid of all that all the heat that they put back into the system. And generally that’s done by cooling towers at the top of the building. So you can imagine there that at some point, we’re taking the whole load for the building and connecting the chillers in the basement and the cooling towers on the roof.”
There is also a large heating system, which is based around gas fired boilers. This is possibly the only change David says would probably be made if they were designing the building now. An electric heating system in 2022 looks more future-proof, because the electricity grid is decarbonising as part of the UK’s route to Net Zero Carbon. But this is the nature of designing a building for a world that does not yet exist.
“And then the ventilation on this building is done by what we call air handling units. And if you can imagine some double decker buses parked partway up your building, that gives you an idea of the scale of these units. We’re moving enough air around for 12,000 people. So there’s some pretty big demands on the space.”
Those are the key mechanical systems, and electrically there are large transformers in the bottom of the building taking the high voltage off the street utility and dropping it down to 400V.
“And because tenants in a building like this are always really interested in the resilience, so they want to be able to keep their operations going, even if there’s a fault somewhere in the system. We’ve got a lot of duplication on the electrical infrastructure to keep that going.”
Another key part of the electrical infrastructure is having standby generators at the top of the building to keep everything going in the case of an outage.
“And the other thing you get from the generator system is we’ve got a lot of life safety systems. So, in a tall building, we’ll have things like sprinklers, we’ll be doing smoke extract from the basement will be pressurising the stairs with air so that if there is a fire anywhere, it keeps them clear of smoke. And then there’s fire detection and alarm systems etc.
So yeah, there’s a not only do we need to consider how things work on a day-to-day basis, but we need to work out what happens if there’s a fire and then that’s probably one of the most interesting parts of the of the whole design and subject to a lot of scrutiny. But actually, it kind of sits there in the background and hopefully, people never know it’s there.”
The building also uses lifts for emergency egress in the event of a fire. This is because stairs in tall buildings are a serious obstacle for the mobility impaired or the elderly.
How 22 Bishopsgate achieved this is fascinating, and the subject of one of the first ever episodes of Engineering Matters. See the episode we released on 21 August 2018 titled “In the event of fire, use the lift”.
Last but not least is plumbing, getting fresh water around the building for occupants, for the restrooms, and for other uses around the building.
“And also providing drainage and you know, trying to recycle water where appropriate, and dealing with rainwater from the top of the building and getting it all the way down. And as you can imagine, in a tall building, one of the key challenges is trying to keep the core of the building where all the lifts and the stairs and the services distributed as tight as possible. So we’re always looking at ways of optimising all those different systems to minimise the impact.”
From an M&E point of view, but also a challenge for Padilla-Philipps’s structural design is that there is a lot more competition for basement space in a modern skyscraper.
“We have a building that was sort of 50% bigger so we started off by talking about all the plant that we’re going to need and some of that would ideally have been in the basement but when you put a bigger building on the same basement and that plant or gets a bit bigger so on its own, so that makes the basement a lot more constrained.”
A larger building required Larger areas for deliveries, cycling is more popular so cycle storage and the showers that goes with that also increase compared with the previous design… so a lot of the plant that would normally go in the basement gets kicked upwards to plant floors that are spaced higher up the building, which in turn competes with restaurants and other spaces…
This resulted in some competition with the amenities, as various installations had to be moved further up the building. Until they reached the top and needed to begin worrying about not encroaching on the flightpath of London City Airport.
Designing the façade
The façade of 22 Bishopsgate is another feature that was ahead of its time.
Amy Holtz, Director of Sustainability at PLP Architecture says, “Externally, we wanted the ability, the building to behave almost like a chameleon on the skyline. The facade, if you’re looking at it through the day, it changes in response to the light levels, or the viewing angle and the surrounding environment. So often, you can see it go from transparent to milky white, to reflecting all of the clouds.”
And it’s not that those are all different facade types.
“It’s that we carefully crafted the angle, and the clarity of the glass so that it did become that chameleon.”
The façade system is what is known as a closed cavity façade, which has three panes of glass. Two are double-glazed, then there is a cavity, then a third pane. The cavity is pressurise and contains an automated blind. As the sun’s energy hits the building, initially some radiation is reflected from the outer face of the external glazing. A reduced amount penetrates into the cavity where it is reflected back out by the blinds or absorbed heating the air in the cavity that then re-radiates the heat back out.
The inner double glazing with low E coating insulates the hot cavity from the office inside and further reflects the energy back to the outside…. finally a small amount of the solar energy will make its way into the building, this is around 10% when the blinds are fully closed. This all gives the building great insulation in winter, but in summer the blinds are really clever.
They use a geometrical model of the surrounding buildings, and sensors to detect the position and intensity of the sun. It then makes an intelligent decision as to when it should deploy the blinds. So if there are clouds already blocking the sun from the façade, it knows that it doesn’t need to block the heat. Without all of this it is necessary to design a darker façade, resulting in a gloomier office environment.
“That’s not just for fun, because we thought it would look nice,” says Holtz. “It’s also performing something and it’s also helping to make the building better for the people within it, as well as something special when you’re seeing it from afar. It’s a slightly reflective glass that we’ve wrapped around the facade and it in a way it further accentuates the varied and dynamic appearance of the facade.”
An entrance on a human scale
The first thing people see in a large building is often a grand entrance hall, but for Twenty-Two, the team was keen to have something on a more human scale.
“It’s the civic face of the building. As we go in, it’s a crafted and man-made juxtaposition to the glass and steel tower above,” says Holtz. “So you get above level three, the level three market we have a cornice line created by this concrete and glass canopy that has intermittent artwork by Alexander Beleschenko along that run.
“But we worked quite carefully to make sure that the base felt human that it didn’t feel like this tower that it brought you because you see the tower from a distance and it’s a special thing and, and the glass is working incredibly hard and the facets are working and everything is creating this, this whole this whole element. But as you walk up a pedestrian scale is a different experience.
“You don’t see that tower as you’re walking down Threadneedle, and you get closer and you approach it, you see, you see the lobby, you see this, it’s really civic space. And it’s designed to be open to the public to walk through. In a way it serves as a changing art gallery.”
They haven’t just plastered the entire building in stone because “that’s what you do”. They didn’t want to have a traditional entrance hall.
“And if you walked on Bishopsgate you feel that you see people walking along and stopping and looking and looking and they look up at the canopy, and they look in at the artwork. And I think they want to go in. I mean, I know I want to go in!” says Holtz.
The success of a major building development such as Twenty-Two rests on whether it has accurately assessed and predicted the future needs of its tenants. And it is competing against smaller buildings that have been conceived closer to the present.
Luckily, the Lipton Rogers made the decision to push technology into the building. For example, contactless entry in the entrance hall, so people wouldn’t have to juggle identity passes, coffee and work materials. Although unintentional, this turned out to be perfect for the pandemic.
Now with the destination office a key part of the hybrid working setup that many city workers have adopted, Twenty-Two’s amenities stand it in good stead.
So here is another prediction. As we as a society become more concerned with embodied carbon, buildings of the future will have to reuse existing structures to an even greater extent. With no more undeveloped land in London and the centres of other major cities, it is a prediction you can rely on. Far more than Nostradamus.
