Friday, 28 November 2014
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Design driven

Naeem Hussain of Arup believes his architectural background helps him to create the best possible bridge for the location. Stuart Nathan reports

Naeem

NAEEM HUSSAIN

Bridge business leader, Arup

Education
Hussain initially studied engineering at the West Pakistan University of Engineering and Technology in Lahore

1967 Design studies, Architectural Association School of Architecture, London
1971 DIC, MSc (Concrete Structures), Imperial College

Notable projects
1988
Design leader for Second Severn Crossing
1994 Project director for the design of Øresund Crossing, Denmark-Sweden
1994 Design leader for Hulme Arch Bridge, Manchester
1996 Engineering manager for civil engineering structures on Channel Tunnel Rail Link
1997 Bridge engineer for Thames Gateway Bridge, London
2001 Project director for Third Macau-Taipa Bridge, Macao
2001 Project manager for Stonecutters Bridge, Hong Kong
2008 Main crossing manager for Forth Replacement Crossing, Scotland

If you drive in the UK, you’ve almost certainly driven across one of Naeem Hussain’s bridges. The Thames Gateway bridge at Dartford is one of his, as is the Second Severn Crossing linking England and Wales and the Hulme Arch bridge in Manchester. His structures span waterways around the world, from Nigeria  to Hong Kong, where he was lead designer of Stonecutter’s Bridge, one of the world’s longest cable-stayed bridges with a span of more than a kilometre. And he’s about  to make his mark at a site that can only be described as iconic — the Forth Estuary in Scotland, next to the Forth Bridge, probably Britain’s best-known engineered structure.

Bridge

But although he was last month honoured by the Royal Academy of Engineering with its highest individual award, the Prince Phillip Medal, Hussain is very conscious that to the general public he’s  an anonymous figure. ‘I’m not so worried about people not knowing my name, but I am worried about the image of an engineer in Anglo-Saxon countries,’ he said.  ‘I want to project the role of the engineer, so people know that we are the people who are creative.’

Hussain came to bridges indirectly. ‘I graduated in Pakistan in the late 1950s and I wanted  to study architecture, but in  those days we didn’t have any architecture schools, so I came  to the UK in 1964 and went to the Architectural Association,’ he said. ‘It was one of the best periods I’ve ever spent. But in the second year, the course moved on to structures, and I’d done those; I was already an engineer. So I went to work  on the M5 project for a while, in the Midlands, and that’s when I first thought that bridges were something I’d like to do.’

One of the things about bridges that most appealed to Hussain was that he saw them as a chance to mix architecture with engineering: thinking that, he said, wasn’t common in the mid-1960s. ‘I was lucky to join Arup. By that time,  I’d been to interviews with all the mainstream bridge contractors, and they were all sceptical that  I’d done any architecture. When  I came to Arup, I actually didn’t want to mention it, but I found that they were even more interested in architecture than I was. I’d found my soulmates. Since then, I’ve grown with the firm.’

Hussein believes his insight into architecture is a boon to helping design the best possible bridge for the location; he refers to the union of engineering and architecture  as ‘total design’. ‘I go through the process of looking at the project  in a space and not just thinking about how to analyse it, because we know how to do that — it’s not  the point,’ he said. ‘The point is: what do local people want? What is the context of the bridge? And, very importantly because we do a lot of public sector work, what is the budget? And it’s not just the bridge, because they’re usually part of a much larger engineering project — the landscape around it and how it fits in.’

Virlogeux made the Millau Bridge, not Lord Foster; architects aren’t the orginators

And it’s in no way a one-person effort — something that feeds  into Hussein’s reluctance to be personally identified with his projects. ‘We have a workshop-type approach; we look at things and discuss, then the gem of an idea comes and we develop the ideas and talk it over with the clients,’ he said. ‘It’s funny how the brain works — you assimilate a lot of data, and then you go completely blank. Then at odd moments, often when you’re discussing it with your friends,  you find the design evolves.’

Stonecutter's Bridge

Long way: Stonecutter’s Bridge in Hong Kong is a cable-stayed bridge that spans more than a kilometre

Many of Hussein’s bridges  have been cable-stayed, a fact  he attributes to the increasing availability of computing power. Cable-stayed bridges are multiply-redundant structures, he said, and this makes them hard to analyse by hand. ‘Early on, they were developed because of the shortage of steel post war — the question was how to economise on materials. But up until the early 1950s, the cable-stayed bridges had relatively short spans, because you could only analyse the structure with a few cables — maybe 200m span maximum.’

Once computing became available, the possibilities of cable-stayed bridges expanded dramatically. ‘Michel Virlogeux, who’s best known for designing the Millau Viaduct, was the first  to go to almost 800m with the Normandy Bridge. In the last decade, cable-stayed has taken another leap forward, and we’re now looking at a maximum span of around 1,200m. But these distances are all to do with economics — beyond these, suspension bridges would be cheaper to build.’

On the Forth project, Hussein has broken new ground — the new bridge will be a cable-stayed design with three towers and with the cables crossing over: a first at this scale. ‘The issue was, from a visual point of view, how to build  a cable-stayed bridge that didn’t dominate the other two,’ he explained. ‘The beauty of the site is that we have the Beemer Rock in the middle of the estuary, and that immediately suggested three towers: three cantilevers on the rail bridge, two towers on the road bridge and three towers on the cable-stayed. It’s a wonderful symmetry, with the three bridges coming to a point in the north.’

But the size of the towers was  a major issue. ‘When we came  on board, the design had huge pyramid towers,’ Hussein said.  ‘The genesis of that was the Rion-Antition Bridge in Greece, which has massive towers. The issue with three-tower bridges is the stability of the middle tower — and the massive pyramid is a solution to that.’ Crossing the cables greatly improves the stability, however, and it allowed the towers to be slimmed down dramatically. ‘That’s where architecture and engineering come together. When you have the theoretical structural background, you can use it in the architectural sense.’

Hussein also praised the client, Transport Scotland. ‘You need an enlightened client. They asked us if anyone had done this before, and we said “no, not on this scale, but it isn’t new technology; it’s been tried and tested”. They were prepared to say “alright, let’s develop it”. We developed it to a very high level  of detail, with a lot of wind tunnel work and a full theoretical analysis, and we went through  all the construction processes  so, when it came to tendering for the contract, they could be very confident that it could be done.’

Scotland's Forth Crossing

Iconic: Hussain is about to make his mark on Scotland’s Forth Crossing

It definitely irks Hussein that engineers don’t get full credit  for their achievements in the  UK. ‘Michel Virlogeux is the man who made the Millau Bridge, not [architect] Lord Foster; architects aren’t the originators,’ he said. ‘Car designers are needed but it’s the engineers who create the car.’

The confusion over the title  of engineer in the UK — is it the person who develops technology or the person who fixes the fridge? — means that innovation isn’t understood or appreciated here. ‘The reason it’s different in Germany or Scandinavia is that they respect people who innovate, and they know who they are.’

‘So maybe we do need to show the face of the individual,’ he said. ‘You can’t buy status; you have to earn it, and the only way we can do that is to show the public, through the media and especially television, what it means to be an engineer. We should be proud of the title: we should use the word “engineer” and give it its true meaning.’

Q&A

Where is bridge engineering going now?
There’s some interesting research going on in the Middle East and Asia into hybrid bridges, which combine elements of cable-stayed and suspension bridges. Theoretically, they could go up to 2km in span.

Is that the limit for the span of a bridge?
Not necessarily. Theoretically, a suspension cable itself can span 8km, but then it wouldn’t be able to support anything, so maybe the limit for a suspension bridge is about 4km. But we’re looking at innovative solutions, such as for Djibouti and Yemen, and the Straits of Gibraltar, where we have back-to-back suspension bridges with a 3km span.

What sort of technology would that involve?
The water depth is about 200m, so you’d be looking at offshore technology — the sort of thing used on North Sea oil platforms. But we know all about those, so what’s the problem? You can marry innovations in different technologies, from deep foundations off shore and structures based on known materials.

And with other materials?
It’s going to happen that we’ll use composites — the automotive, aerospace and marine industries are all adopting carbon composites. Civil engineering is by nature more conservative — or at least the clients are — but it will happen.

What’s the potential with composites?
It’ll allow us to span greater distances, with things such as kevlar cables. But our thinking will have to change. Your structure might have a 200-year design life, but parts of it will have a 50-year life. We’ll have to design with replaceable parts, such as sections of deck or cables.


Readers' comments (1)

  • Excellent overview article!
    Thank you.

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