Pier Luigi Nervi is a great builder because Italy is scarce in trees and World War II demolished northern Italy. A stupid thing to say, I know, for even before the War Nervi had demonstrated undeniable genius as an engineer. Yet Nervi's is the genius of solving problems. Destruction and financial ruin in Italy necessitated speed and economy, driving Nervi to the discovery of "ferro-cement," a new reinforced concrete--cheaper, more elastic, and, of the essence, more rapidly constructed than older versions.

This discovery is typical of Nervi, of his career and of his whole approach to architecture. Widely regarded as an engineer, Nervi sees himself as an architect and architecture as a practical question of construction. Architecture's aim is to build, and buildings, regardless of beauty, cannot exist on paper; they are possible only when they meet immediate demands of site, specification, and budget. Beauty is desirable, but construction aiming at "economic efficiency," Nervi argues, is architecture's goal.

Nervi graduated from the Civil Engineering School of Bologna in 1913 and immediately joined the growing number of engineers who saw in reinforced concrete the revolutionary solution to Italy's historic poverty of steel and concrete. He regards his next years, spent working for a firm of cement contractors (with the interruption of military service), as formative. "It was here that I really learned of concrete's great number of use."

In 1920 he founded his first contracting firm. In 1926 he initiated the now familiar pattern of submitting architectural designs of structural concepts aiming at efficiency and economy.

His second project, the Municipal Stadium of Florence (built in the early thirties), demonstrated to an international audience a thesis which Nervi has since maintaind: that the correct engineering solution to a difficult structural problem is a precondition not an obstacle to beauty of form, and that the architect, aiming at correct construction alone, can produce art.

By the thirties a half century of construction in reinforced concrete had dissipated public resistance to the new forms. Nervi's stadium with its famous external, spiral staircases reached an audience increasingly enthusiastic about the new substance and won him immediate acclaim.

The spiral stairs represent an excellent example of the intimate relation between structure and form conceived by Nervi. Their immediate purpose, Nervi explained, was to prevent the logjams which inevitably occurred when masses of spectators crowded into the traditional interior tunnels. Their construction delayed the completion of the Stadium, yet in finished form they not only solved the problem of crowding, but were immediately recognizable even to the untrained eye as purely aesthetic triumphs.

It was in constructing the spiral stairs that Nervi first hindered by the rigidity which an interior timber formwork imposed on reinforced concrete. The next twelve years witnessed Nervi's various modifications of the skeleton of reinforced concrete and "in retrospect' strikingly continuous progression toward ferro-cement.

The new material substituted flexible steel mesh for timber, in a way that simplified the cementing process and thus allowed for vital short-cuts in reinforced concrete construction. The substance could be mass-produced at a ferro-cement factory established by Nervi in 1945. Prefabrication, a second vital innovation, allowed the builder to transport parts from a center of mass production to the building site and simplified the actual job of erecting the structure.

The elimination of timber beams or their steel equivalent made ferro-cement cheaper, lighter, thinner, and the new process of production incomparably faster.

Nervi's ferro-cement dome ceilings, strengthened by corrogated beams are today among his most familiar works. Conceived an executed as technical problems, these domed ceilings nevertheless attain a soaring beauty not foreseen in by the builder--entirely dependent on structural design yet not included in it.

"What is beauty?" Nervi asks. "I am a builder. I am no artist. People tell me some of my designs are beautiful, and I am glad. But I don't aim at beauty." Nervi maintains that the different stresses which different situations place on the physical properties of reinforced concrete determine its basic form, leaving the architect a "margin of freedom" to decorate but preventing the aesthetic from ever being a fundamental architectural aim. Although structure in its immediate situation has always been his primary concern, in many of his constructions he himself demonstrates the beauty which a man of artistic genius can create within the "margin of freedom."