Re-engineering the European City.

A stellar line-up of architects and thinkers consider the evolution of cities.

The recent AR-Arup conference Re-engineering the European City at the RIBA had the avowed purpose of 'exploring the impact of economic, social and climatic change'. Two architectural grandees, Terry Farrell and Richard MacCormac, led off with thinking based on their independent research (and some bitter experience). Then, perhaps not unexpectedly given the sponsor, three engineers with some really interesting technology-orientated material plus the evergreen Rick Burdett reprising his summary of the Venice Biennale whose Cities theme last year he curated. Then the star turns, city turnaround hero, David Mackay and the immortal Zaha Hadid in conversation with our own Peter Cook. There were no planners. As Terry Farrell pointed out 'Planning is in disrepute'.

Deceptively unassuming, David Mackay is always so impressive because he actually does cities: he and his Barcelona practice, MBM, have worked on, at last count, interventions in 46 European cities--currently it's Plymouth. He began by asking such questions as why, when traffic moves at 12 to 20km per hour, pedestrians are fenced off from city roads and not allowed to cross between waiting traffic, why pedestrians have less space than cars, why we visit historic areas of a city and not the suburbs or the industrial estate. He said, 'The key lies in understanding the social value of the public space and how it is formed. This means that it must be formed together with a project that can be carried out and finished so that they can produce the positive effect of a metastasis transforming the urban stage'.

Pessimistic about the Olympic projects (and their aftermath) his experience is that political leadership is always central. He says, echoing a general scepticism about consultation, 'In the UK nearly all the politicians wash their hands of involvement, substituting it with an often confused public consultation [and] layers and layers of agencies stepping on each other's toes'. Mackay points out that we (and the legislation and the planning procedures) have things the wrong way around. He says that we 'must see the city from the particular to the general' not from the general to the particular: that any action plan is not a metaphysical vision from which the detail emerges but a collection of projects which are immediate responses to local needs. These can change a neighbourhood more radically than any grand and therefore never implemented plan.

Earlier Terry Farrell used the almost totally greenfield Thames Gateway region as the vehicle for exploring planning thinking based on landscape. He said in explanation, 'It depends on what the client asks you to do. But if you don't have a client you can take a god-like view. I realised that landscape was the key' His radical proposition for the gateway included estuarine islands to stop tidal surges, locating all housing next to existing housing and turning the whole of the rest into a great national park complete with surge-resistant wetlands. But, he pointed out, the politicians aren't interested in 100 year projects. Their way to kick such visions into touch is to put them out for consultation.

Like Farrell, Richard McCormac had been spending office profits on research projects. Intrigued by recent debates about city densities and target figures, often snatched from the air but given weight in official planning, he had worked on a run of density propositions, based admittedly on his own architectural solutions. They suggested that net dwelling density was not a very useful measure for anything. His plea was, if you had to talk density figures, to look at gross community density which included accessible social and commercial infrastructure and minimal roads. His Sustainable Suburbia research supported the idea of high density pedestrian communities facilitated by a permeable road network, which, against what you might expect, results in a much greener environment.

Like the two architectural knights, radical engineer Hanif Kara's Adams Kara Taylor funds its own city research: he said, 'It's not paid for but we do it all the time'. He also talked about an unexpected issue of city re-engineering: the archaeology of piling. Because the City of London has been rebuilt over the centuries it is difficult for modern engineers to physically get piles through generations of previous piling. Paris's La Defense has an equivalent problem in its rats nest of underground rail lines. One of the big problems is how to visualise such problems--and his practice is modifying and writing software which can produce parametric models of the city in which the designer can run what-if scenarios.

Arup's Andrew Sedgwick offered a nuts and bolts explanation of similar computer optimisation. He said, 'At the pre-planning stage there are a whole series of parameters which the designer has to evaluate and juggle with. But frequently there isn't the time. Now it is possible to do a large number of iterations with different parameter values in order to meet planning criteria'. Here are sequences of perhaps a thousand what-ifs which might involve several dozen changing parameters. The software still has limitations, for example it can't do vortex shedding analysis. But hey. This doesn't mean the end of inspired design. But it does herald the beginning of very fast and checked-out inspired design. His Arup colleague Michael Bevin talked about what recently has been a controversial topic: engineering for zero carbon. It was not the place to argue the evidence. He acknowledged the need to get a handle on conventional wisdom because although it is possible that we can meet current official targets our chances of actually doing so are maybe 60 per cent. But, he said, 'We need to reconsolidate our values rather than just asking how do we fix it'. In the question and answer session succeeding his talk came the memorable image of the meeting. Concatenating sincerity, developers and sustainability somebody said: 'Like hotel thieves, developers go around looking for open doors. Once they get in they sprawl on the furniture'.

Richard Burdett had curated last year's Venice Biennale with the theme of Cities. He pointed out that in 1900 10 per cent of people lived in cities. This year half the world's people live in cities. It is the result of the low value of agricultural labour and, he argued, the strength of the image of the European city in the collective mind of the developing world. And other things. But the speed of change impacts on the soul and the mind. The new city has a scale which can't easily be comprehended.

Zaha Hadid was, happily, on another plane from this prosaic stuff. Her sweeping interests, teased out by the master interlocutor, Archigram's Peter Cook, were in such notions as urban space, seamlessness, building navigation, solitude, multiple grounds, spatial suspension, layering and the relationships between structure and programme. Earlier David Mackay had warned about attempting mindlessly to repeat the Bilbao effect, the hope that a single iconic building might lead to a city's renaissance. Yet you imagined that a Zaha building in a tired old city might lead precisely to that and if not to a kind of glory.