The key to the city - urban renewal program in Lyons, France - Cover Story

Architectural Review, The, Jan, 1996 by Peter Buchanan

This first phase of an urban revitalisation scheme in Lyons is designed as a dense, multi-use precinct for work and play, which also connects with nature.

When complete, the Cite Internationale de Lyon will consist of two chains of buildings flanking a central pedestrian route that curves between a prominent bend on the River Rhone and the nineteenth-century Parc de la Tete d'Or. Close to the city centre, yet also isolated from the rest of its built fabric, the complex (of which the first phase is now finished) will be neither city nor suburb as we know them, but a dense multi-use precinct in which people live, work, meet and play. Though it brings to the citizens of Lyons new cultural, leisure and conference facilities, it is being built primarily to attract and serve the larger international community to which Lyons is well connected. But like most of Plano's works it is also designed to connect with whatever nature is close by, in this case cementing a new connection between the park and the river. The buildings are also significant in being part of a series by the Building Workshop that are clad in terracotta units, and are also the first in a series using a secondary, external glass skin to achieve savings in energy consumption.

Lyons is well connected to Paris and Marseilles, being on the TGV line that links these cities. To capitalise on these links and that to Geneva, an architectural competition was held in 1985 to rehabilitate the premises of the Foire Internationale de Lyon and to add to them a conference centre. The premises had been built, starting in 1918, as a series of slab blocks that fanned in an east-west arc between the park and the river. The winning scheme by the Renzo Piano Building Workshop, in collaboration with landscape architect Michel Corajoud, proposed linking the old blocks with a curving pedestrian mall and improving the connection with the park. The latter was to be achieved by moving most of the traffic on the road between the buildings and the park to a new road along the river bank.

Later investigation revealed that, even if modernised, the blocks would not attract tenants because they faced each other rather than enjoying the views of park or river. So it was decided to demolish all the blocks except the main entrance pavilion, known as the Atrium, and to rebuild according to the broad precepts of the competition scheme, but now with the blocks aligned as pairs on either side of the spine rather than straddling it. Car parking would now be in garages below these blocks.

Much of the first phase, the conference centre and a pair of office blocks, is now complete. Construction of a contemporary art museum behind the old facade of the entrance pavilion, and a multi-screen cinema across the pedestrian route from it, is also well advanced. The riverbank boulevard is now open, its edges and the riverbank landscaped, and the once busy road along the park edge is now a quiet access way with street-edge parking. A backer has yet to be found for the four-star hotel planned between the museum and cinemas and the completed offices. But construction of another pair of office blocks beyond the conference centre will start soon. Later phases will consist of more offices and housing, stretching east and west of the first phase.

To unify the whole, all the blocks, with their differing heights, functions and fenestration, will be clad in the same components. The Building Workshop has used terracotta cladding before, on the Ircam tower (AR October 1989) and rue de Meaux housing (AR March 1992) in Paris, and on the Harbour Master's office in Genoa's docks (AR January 1993). Here though, instead of groups of smallish units being held in a surrounding frame of metal or grc, larger units span independently up to 1.4m between the vertical elements that support them, the larger size and horizontal emphasis being matched to these chains of biggish buildings that will be seen across river and park. As before, the cladding gives an enlivening delicacy of 'grain' to the buildings, as well as a protective finish that is warm to look at and weathers well.

Adding further to the grain, and giving a shimmering dematerialising effect that Piano refers to as pointillist, are stretches of unframed glass panes (some of which pivot as louvres) that project forward from the terracotta facade. This is the first of a series of buildings by the architect to use such a device to improve energy efficiency while still allowing a sense of contact with conditions outdoors. Piano is adamant that he will not sacrifice the latter of these goals - often assumed to be incompatible - which are achieved by increasing the portion of the year during which even tall and exposed buildings can be naturally ventilated. The outer glass panes break the force of the wind and intercept the rain so that the conventional windows behind them can always be open. In summer, night air cools the buildings, while during the day the gap behind the outer layer of glass acts as a thermal chimney, ventilated at the top and drawing cool fresh air through open louvres and up the facade. In winter the louvres are closed to trap air, warmed by the sun and heat escaping from inside, that forms an effective insulating layer. These outer glass skins are not used on the sheltered facades along the pedestrian spine, and only face park and river. On taller blocks they curve back at the top to shelter roof terraces and give the buildings a distinctive profile.