Winter 1959: The New Shape of Paris

“Leaving Paris by the Pont de Neuilly and driving out north- westwards, there suddenly appears before you, white in a morning sunlight, this new shape – dazzling, unexpected, immense. Its great curves dwarf the avenue trees and the avenue houses, and on its slopes small busy men look like skiers on a mountain side.”

This dazzling new object, then in the final stages of construction, was the Centre National des Industries et Techniques, a vast exhibition hall that epitomised postwar France’s new-found economic bounce. It was “by far the biggest building in Paris, covering some five and a half acres”, and marked the birth of the La Défense commercial district on the west bank of the Seine.

And then there was its shape – an equilateral triangle in plan, rising up into a vaulted dome, like a billowing sheet pegged down at the corners. It was made entirely in structural concrete, with each arching side stretching for 218m. This was (and remains) the longest known span for a thin-shell vaulted structure.

The scheme was devised by three titans of French architecture: Robert Camelot, Jean de Mailly and Bernard Zehrfuss, all past winners of the nation’s prestigious Prix de Rome. But the actual business of getting the roof to stay up was the work of structural engineer Nicolas Esquillan.

The structure was a double shell designed in three fan-shaped sections. Inside, there were no columns – an engineering feat to match the cutting-edge machinery on display. “The great umbrella sections of the roof – sharper and more distinct than outside – soar up dizzily to their 150ft high crown,” marvelled CQ.

The shells – parallel in form and spaced 2-3m apart – fanned out from 7m-high corner abutments in vaults made up of 18 “undulations”. At the dip in each undulation, they were joined by a precast concrete web, with transverse webs at 9m intervals, forming a structure “similar to a plane wing – with great lightness and resistance to bending, torsion, buckling and stresses in all directions”. Browse through nearly 80 years of Concrete Quarterly at concretecentre.com/archive

Browse through nearly 80 years of Concrete Quarterly at concretecentre.com/archive

A book, The World Recast: 70 Buildings from 70 Years of Concrete Quarterly, is available from www.concretecentre.com/publications

Access the full CQ archive here.