Negotiating the glass doors of Arup's Fitzroy Street headquarters in London, it is not immediately clear what kind of organisation this is. The address suggests advertising or media, an impression that is hardly contradicted by the stone floors, the exotic flowers in the outsize glass vase and the tiny spotlights floating off the ceiling, all of which could be props for just about any lobby with ambitions to be taken as vaguely modish.
But if you look a little harder, you will see clues - even though most of them tell you what this place is not, rather than what it is. No self-respecting advertising agency would risk leaving its clients in a pair of sludge-green sofas like these. There is no rack of awards and no row of gently ironic clocks, reminding you what time it is in Sydney or Tokyo.
Despite appearances, though, this is not an organisation that sells soft drinks or running shoes or hedge funds or financial derivatives. These are the people who worked out exactly why the rails cracked in the Hatfield train disaster, and who used to take a certain amount of glee in crash-testing nuclear flasks to destruction. By temperament, they have a natural antipathy to the sleek and the superficial.
At the reception desk, the first thing you see is a little silver and white model of a section of a bridge. Close inspection reveals it to be a miniature slice of the wobbly Millenium Bridge across the Thames, the one that caused Arup so much pain when it opened and then immediately closed. Defiantly, the model is equipped with a mirror, angled in such a way as to ensure that you can't miss the rubber dampers and the shock-absorbers strapped to the underside of the bridge deck, at a cost to Arup running to £5 million, to cure the problem as unobtrusively as possible.
Next to the model is an even more revealing object, a tiny portrait bust of an elderly man. His bespectacled, owlish demeanour and prominent forehead suggest the Mekon, the evil green genius on his flying sauce-boat from the Dan Dare cartoon strip of the 1950s. This is Sir Ove Arup, the benign father figure of an engineering business that is now 7,000-strong with 73 offices in 32 countries.
It has grown into a global giant thanks to its reputation for getting things done, and new recruits are still issued with a personal copy of what Arup initiates call The Key Speech. A less level-headed organisation would have turned a less level-headed founder into a cult by now. The founder gave the speech in 1970, after he had retired but before he gave his business, in trust, to its employees. The document shows its age now, but it still provides a convincing strategy for running any business that depends on managing large numbers of highly gifted people with well-developed egos.
Arup got straight to the point. 'There are two ways of looking at the work you do to earn a living. One is the way proposed by the late Henry Ford. Work is a necessary evil, but modern technology will reduce it to a minimum. Your life is your leisure lived in your free time. The other is to make your work interesting and rewarding. You enjoy both your work and your leisure. We opt uncompromisingly for the second.' And then he went on to talk about the pursuit of lasting happiness in a way that effortlessly swept along even a room full of men with slide rules in their top pockets.
Arup died in 1988, but the company he started in 1946 has expanded hugely since it became a trust. In the past seven years alone, staff numbers have increased by 70%. Turnover peaked at £405 million in 2002. A weakening dollar helped bring the figure down to £395 million last year, still a big increase from the £274 million it racked up in 2000. But the point of Arup, then and now, is not just to generate cash: it's to build remarkable structures. Or, as the company puts it with unaccustomed immodesty: 'We shape a better world.'
Arup was the man who got the Sydney Opera House built, while its architect, fellow Dane Jorn Utzon, agonised over how to make the soaring concrete shells stand up and finally gave up, paralysed with indecision. To this day, Utzon and his supporters still see Arup's refusal to quit the project when the architect was manoeuvred into resigning the commission as a betrayal. Arup himself never talked about it in public. But the story, as set out in Peter Murray's book The Saga of Sydney Opera House, suggests an engineer at the limit of his patience with an impossible architect, determined to do his best for both the client and the building's owner and to keep the spirit of Utzon's design.
Despite the controversy, Sydney received only positive results from Arup's relationship with architects, on which so much of the company's more high-profile business depends. It worked time and again with Renzo Piano and Richard Rogers - most notably on the Pompidou Centre in Paris - and with Norman Foster on the Swiss Re tower in London. Arup was Daniel Libeskind's engineer on the V&A Spiral, and has worked with James Stirling, Portugal's Alvaro Siza, Arata Isozaki from Japan and Jean Nouvel in Paris, and with just about every ambitious architect in the world.
For an untested young architect, having Arup on the team is the best endorsement he or she can have. It is inconceivable that when Rem Koolhaas won the biggest commission of his career, to build Central Chinese Television's HQ in Beijing, the Chinese government would have countenanced his design without Arup's guarantee that it could be built.
But Arup has an unmatched record on infrastructure projects too. It built the metro systems in Bangkok, Hong Kong, Taipei and Singapore. It's in the running for New York's new Second Avenue subway line - if it ever gets built. It has made possible skyscrapers around the world, as well as bridges and runways and highways. It explores issues of nuclear safety and power generation.
What got Ove Arup himself noticed and made him so successful was the sheer elegance he brought to everything he did. But what distinguished his company from its competitors was what he did when he'd made up his mind to retire. He turned it into a trust, its shares held by the company's employees until they leave or retire, with profits distributed according to shareholdings, John Lewis-style. It has proved a remarkably effective way of attracting and keeping the loyalty of a large number of bright professionals, people who would be fully capable of making a success of business on their own but see the advantages of working under the umbrella of a big, non-bureaucratic organisation that allows them freedom. It's a business run not by suits, but by successful engineers.
Arup was born in Newcastle in 1895, the son of a Danish vet and a Norwegian mother. He was educated in Hamburg and Copenhagen, studying philosophy before turning to engineering. He worked briefly in Germany, then moved permanently to London in 1923. He became chief designer for JL Kier, a Danish construction company, and was responsible for, among other things, the effortless elegance of the interlocking concrete spirals of the Penguin Pool at London Zoo. In 1938 he set up in business with his cousin, Arne Arup, manufacturing concrete air-raid shelters to protect the civilian population during the war and designing Mulberry floating harbours for the Normandy invasion.
In 1946, at the relatively advanced age of 51, he started on his own. With an enormous variety of projects, from Coventry Cathedral to the Carlsberg Brewery in Northampton, he changed the face of Britain. He tried to inject the elegance of what he called 'total architecture' in every project. In the process, he created a practice that attracted the brightest young engineers, and encouraged them to spend their whole careers with the organisation.
Today, the firm still does its best to attract young talent, targeting recruits even before they go to university. It offers them sponsorship as students and the chance to work on high-profile projects after they graduate. Kate Hill, now Arup's youngest-ever female associate, joined the company as a pre-university trainee in 1991, and spent five years in Hong Kong before moving to Arup's campus on the edge of Birmingham to work on the M6 toll road and Oxford's new railway station. 'In Hong Kong, I was sent out on site on my second day. At Arup, you have the chance of working on huge projects very early on.'
Arup's approach to moulding its recruits does not suit everybody. The organisation breeds the kind of self-satisfaction common to the upper echelons of the BBC or the Foreign Office - which some find problematic. Indeed, there was a certain amount of schadenfreude when the all-conquering Arup found itself struggling to deal with the fallout from the Millennium Bridge, and what was seen as its hubris in refusing to acknowledge the inherent instability of such a long, thin structure with so little built-in rigidity.
Tony Fitzpatrick, who led the team charged with fixing the problem, maintained that the original design had dealt with all the difficulties that could have been foreseen. The problem, he said, was caused by a factor that nobody could have predicted. Shortly after the bridge was fixed, Fitzpatrick abruptly moved to run Arup in North America, where he was tragically killed in a road accident.
Despite its apparent self-confidence, the lingering determination at Arup to do things its own way may reflect Ove Arup's view of himself as an outsider. A well-known member of the engineering establishment tried to have him blackballed from the Association of Consulting Engineers because he had once run a contracting business and was thus seen to be tainted by trade. The Royal Institute of British Architects was similarly sniffy in the early 1960s when Ove started an architectural practice, Arup Associates. RIBA accused it of unfair and underhand poaching.
Commercialism was never what drove the founder, however. 'It has always amazed me that people want to go on all their lives just making more and more money,' Arup once said. 'To be a businessman with the idea of making money always seemed to me to be absurd. It just goes round in a circle. You make the money in order to live and you live in order to make money. There doesn't seem to be any idea behind that.'
Peter Rice, who for two decades was the engineer of choice for both Piano and Rogers, and spent the greater part of his career working at Arup before his untimely death, once summed up the nature of Arup's attraction for mavericks. 'I joined Ove Arup & Partners because I had heard it was a place that an oddball could fit in. Ove Arup defined an attitude, an integrity towards what one did that permeated down from his distant sixth-floor office.'
Arup is split into two divisions: the structural engineers, who build the more glamorous projects of the kind that would have fascinated Arup himself; and the less photogenic but ultimately more profitable infrastructure division. These projects are insulated from the downturns of the world economy that periodically blight the construction industry and which caused the firm real pain in the 1990s.
The divide is reflected in the persons of Terry Hill and Cecil Balmond, the two Arup leaders appointed, like the other five board members, by the trustees, who are themselves former board members. Both are Arup lifers, but Hill, the smoothly managerial chairman since April 2004, is an infrastructure specialist. It's his job to hold the organisation together, to talk to clients and to set a course.
'Arup is not a pyramid,' he says. 'We are in this together. There are just eight levels between graduates and the chairman. People who come here from other offices are amazed at the degree of openess we have.'
Balmond, who became vice-chairman at the same time that Hill was appointed, is a Sri Lankan-born structural engineer. His reasons for joining Arup sound very much like those of Rice. 'Arup was an accident. I went to Africa after I graduated, I played music for a while. Then somebody said: why don't you talk to Arup. I was called Cecil by the old man, which seemed significant. The other practices were much more formal. I felt comfortable there. It allowed me to travel; I worked in Nigeria, Sierra Leone and Kuwait. Arup was a massive opening for me to grow as a person.'
Hill is proud of the fact that he works for a trust, and that his only shareholders are his co-workers, who hand back their shares when they leave or retire. 'There is nothing touchy-feely about it,' he says. 'It allows us freedom from short-term profit-making and gives us the space to take the longer view.'
The structure, with its unbreakable trust, has allowed Arup to survive as an independent entity. Practically all the other sizeable engineering consultancies have either gone public or been swallowed up by conglomerates.
Arup's success is built on two distinct but inter-related skills. It has people, such as Balmond, who are prepared to suppress the predisposition of most engineers to tidy up all architectural flights of fancy and sit down with a straight face to make the impossible possible. At times, Balmond has had more than 100 engineers working on ensuring that Central Chinese Television's gigantic new complex of high-rise buildings is stable enough to resist wind and weather loads, as well as earthquakes.
The main structure, with its pair of leaning towers 70 floors high, linked at top and bottom in a gigantic Moebius ribbon, will contain more than 500,000m2 of space, everything from studios to offices. Even though to the non-expert eye it looks as if the unsupported section of structure spanning the void is increasing the load on the two towers, it allows them to stabilise each other. Propping, as this is called, is one of the basic principles on which the structural design is based.
The other principal is what Balmond calls the skin. Externally, the towers will have a mesh of diagonal bracing in a seemingly random pattern. As with the creases on human skin, there is the greatest concentration of lines at the points of maximum stress.
The original idea even had the lift-shafts sloping at the same angle as the towers - six degrees to the vertical - which would have made every floor uniform in layout. But the need to make an early start on construction led Balmond and Koolhaas to go for the simpler if less elegant option of conventional vertical lift-shafts inside the gently sloping towers. This is quicker and cheaper than trying to build a lift that would need to work like a funicular railway, but it means the doors appear in a slightly different place on every floor.
The most serious issue facing the design team is resistance to earthquakes. The structure is designed so that it can go on operating through the kind of earthquake trauma predicted to occur only every 50 years, but it is actually stable enough to shrug off a quake of the order of magnitude that comes only once in 400 years. 'There might be a little damage, but the towers would still be operating,' says Balmond. Even in the worst-case scenario - once in every 970 years - the towers still wouldn't collapse. 'People would be able to make their way out safely, despite serious damage.'
The other face of Arup is the ability of Hill, and people like him, to 'make complex things simple'; to deliver huge and mind-bogglingly sophisticated engineering projects on time and on budget. To be able to do that depends on an organisation that is not fixed about exactly what it is or does, or how it goes about things - an organisation that is prepared to learn new skills and follow what its clients are doing, rather than sticking to familiar territory.
Says Hill: 'Our clients aren't buying our skills; they are buying a new metro system, or a building, and they want the process to be as seamless as possible. We can offer fire engineering and acoustics and structures.' But there are plenty of top-notch structural engineers outside Arup. The firm is a centre of excellence, certainly, and it has shaped the way structural engineering is practised. But it can't be said to have defined the profession.
Yet there are areas in which it has managed to do just that. Its acoustics division, which has worked on everything from the soundproofing of the Jubilee line to the acoustic design of The Sage Gateshead concert halls - where Arup's Raj Patel was appointed ahead even of the architect Sir Norman Foster - is among the largest such practices in the world. With the Soundlab, a computer model that takes the guesswork out of the black art of acoustics, it has transformed the design process.
Patel, like Balmond, brings an unusual range to his specialism. A trained musician, he was on the verge of going to Oxford to study history when he discovered Southampton University's acoustics course. He believes that Arup acousticians have moved the discipline forward dramatically. The age when cutting-edge technology was a person standing in the middle of a concert hall discharging a pistol to measure reverberation times are gone, he says.
'If you look at the one-off geniuses, they are all selling a product. It's the same thing over and over again, but they publish very few technical papers. They say: this is what it will be. When they design a concert hall, they say to the architect: here is your box. I will do what is inside. Our philosophy has never been that. We work with the architects.'
Hill and his predecessors have ensured that the business has not remained as its founder left it. It is not simply that it has grown so far and so fast that makes it different. It has moved into offering services that at times seem indistinguishable from management consultancy.
Balmond, who has never been quite sure whether he wanted to be an architect or an engineer - not something with which all his clients are comfortable - complements Hill's approach with a series of high-profile, more left-field initiatives. He worked with sculptor Anish Kapoor on Marsayas, the huge installation in Tate Modern, and after surviving the Boxing Day tsunami with his family in a beach house in Sri Lanka, is leading Arup's pro bono efforts to help reconstruct the island.
But Balmond has had strategic input into building the business, too. 'I thought: why don't we work in Europe? We were missing out on a large and mature market,' he says. 'I went to see the chairman at the time.' The result is that Arup has opened offices in Madrid, Dusseldorf, Milan and Istanbul.
'The people now in charge of the European offices came up through Arup's design group,' adds Balmond. 'We have been grooming people for Arup's future.'
1895 Ove Arup is born in Newcastle. His mother is Norwegian and his father the Danish consul in Newcastle-upon-Tyne
1923 Arup lands a job in London as chief designer for Danish construction company JL Kier. Projects include the Penguin Pool at London Zoo
1938 Arup and his cousin Arne mass-produce concrete air-raid shelters and build Mulberry harbours - constructed in Britain and towed across the channel for the D-Day landings
1946 Aged 51, sets up Ove Arup, an independent practice, to concentrate on consulting. He later calls his elegant, holistic approach 'total architecture'
1956 The firm grows to 30 employees, servicing huge post-war government reconstruction contracts. Arup's specialist engineering services are now used by most major British architects
1962 Arup is structural engineer on the new Coventry Cathedral, which replaces the old cathedral destroyed in WWII. The company is also making a name in roads and bridges
1963 Arup Associates is established, a dedicated architectural practice. The influential Royal Institute for British Architects opposes the move, accusing it of poaching top talent from other practices
1969 Snape Maltings Concert Hall burns down on the first night of the Aldeburgh music festival. Rebuilt within a year, it is Arup's first concert venue, to be followed by many others
1970 After his retirement, Sir Ove Arup delivers what will become known as The Key Speech, still used to induct new employees and regarded as his defining moment. He says: 'No man is an island. Our lives are inextricably linked with our fellow human beings'
1973 The Sydney Opera House opens - Arup stepped in to ensure its completion after architect Jorn Utzon was unable to make his own design stand up
1977 The firm completes the Pompidou Centre in Paris. Designed by Piano and Rogers, the art and culture gallery is famous for having its entrails on the outside
1979 Arup becomes employee-owned - a partnership of two companies is created, each held entirely in trust for staff. The structure is later simplified to a single company held in trust
1980 Arup Acoustics is formed when acoustic architect Richard Cowell joins. The division constructs major venues, from London's Royal Opera House to stadia for the Sydney Olympics
1986 HSBC's 47-storey Hong Kong HQ is completed, following a brief to build 'the best office building in the world'. Arup's expertise now includes blast and seismic engineering
1988 Ove Arup dies at his home in Highbury, north London, aged 92
1989 The Ove Arup Foundation is established to promote understanding of the built environment. Aimed at students, it values 'concern for, and pride in, the impact we have on the communities in which we live and work'
1995 Arup takes on the engineering of the Angel of the North. The 20m-high sculpture needs 700 tonnes of concrete and 32 tonnes of steel in its foundations
1998 An Arup team completes the $850m Hong Kong International airport at Chek Lap Kok, incorporating 310 hectares of island into a man-made 1,248-hectare passenger terminal
2000 Arup's turnover hits £274.7m. The Millennium Bridge - a design by Foster & Partners, Antony Caro and Arup - is unveiled, but the structure wobbles. Fixing it takes two years
2001 In Cornwall, the Eden Project - an award-winning 'eco-experience' - is completed. In Japan, the 6,700m2 Fukuroi Community Centre opens. It houses a concert hall, swimming pools, workshops and a library, all under an earthquake-proof roof
2003 Inaugural match at the City of Manchester football stadium. The largest new ground in the UK since Wembley in 1913, it was built by Arup for the 2002 Commonwealth Games
2004 Current chairman Terry Hill appointed in April, with Sri Lankan structural engineer Cecil Balmond as vice-president. Balmond originally joined the company because Ove Arup called him by his first name
2004 London's Swiss Re Tower wins architecture's prestigious Stirling Prize. Arup designed the diagonal steel grid that gives the building its distinctive shape
2005 Arup now employs 7,000 people, with 73 offices in 32 countries. It makes skyscrapers, sea-platforms, bridges, runways, railways and highways - and is key partner in the UK's 2007 world water speed record attempt.