Pier Luigi Nervi

Italian engineer and architect

• Born: June 21, 1891
• Birthplace: Sondrio, Italy
• Died: January 9, 1979
• Place of death: Rome, Italy

Nervi was not an architect but rather an engineer whose goal was to create aesthetically pleasing structures. His importance lies in the fact that he was among the first in modern times to reunite architecture and engineering.

Early Life

Pier Luigi Nervi (pyehr lew-EE-jee NEHR-vee) was born in the village of Sondrio in the Italian Alps to the local postmaster and his wife. Nervi remained thoroughly Italian throughout his life, and his work symbolizes the confluence of two major factors: his upbringing amid the aesthetic richness of Italy and his engineering education. Significantly, some of Nervi’s first major works were large domes that may be said to have been influenced by earlier domes such as St. Peter’s in Rome and the dome of the cathedral of Santa Maria del Fiore in Florence. As a youngster, he attended the Ginnasio-Liceo Muratori in Modena. In 1913, Nervi was graduated from the Civil Engineering School of Bologna, where he learned the basic principles of structures (and at the same time satisfied his childhood fascination with mechanical things). His schooling, however, treated art and science as two distinct endeavors an approach that seemed illogical to Nervi.

On graduating from Bologna, Nervi gained employment as a civil engineer with the Societa per Costruzioni Cementizie. The Societa provided him with much experience in reinforced concrete, a structural material that he would eventually master. Nervi remained with the Societa until 1923 (his tenure having been interrupted by World War I when he served with the Italian army’s engineering corps), when he left to work full-time in a firm he had founded in 1920. As a partner in this firm, Nervi and Nebbiosi, he built several structures that drew international attention for their originality and beauty.

It is significant that Nervi began his career just as new materials and a new architectural movement were gaining momentum. During the first decade of the twentieth century, reinforced concrete gained recognition as an important new structural material through the works of François Hennebique, Auguste Perret, Robert Maillart, and others. Furthermore, by the early 1920’s the outlines of the modern architectural movement were being clarified by pioneers such as Walter Gropius, Ludwig Mies van der Rohe, and Le Corbusier. In April, 1924, shortly after joining Nervi and Nebbiosi on a full-time basis, Nervi married Irene Calosi, and they eventually had four sons, Antonio, Mario, Carlo, and Vittorio.

Life’s Work

One of Nervi’s first major works was the Municipal Stadium in Florence. As with all of Nervi’s work, the stadium design began with a concern for economy, and Nervi won the design competition because of the low cost of his project. The outstanding feature of the stadium is the grandstand roof: a shell extending over the seating on cantilevered beams. It clearly demonstrates, at an early point in Nervi’s career, his ability to achieve both beauty and economy with reinforced concrete.

In 1932, Nervi joined with a cousin to form a new firm. This firm won a competition announced by the Italian Air Force in 1935 to build a series of airplane hangars. The hangars, as designed by Nervi, were to become landmarks of reinforced concrete construction. The problem posed by the hangars was how to span an area 330 feet by 135 feet with no internal supports. Nervi chose to make a vaulted roof with concrete ribs, which were cast in place and then covered with tiles. One problem with this type of construction was the vast amount of timber required for the concrete forms. Nervi solved that problem in a second series of hangars that he built beginning in 1940, by using precast concrete ribs for much of the roof’s span. Driven by the need for greater economy in both material and timbers, Nervi had thus created a light but incredibly strong vaulted structure, which only required a roof covering and walls to make a hangar. When the Germans destroyed these hangars by demolishing the supporting columns, many of the roofs remained intact after they fell.

In the mid-1940’s, Nervi developed an important new type of reinforced concrete, which he called “ferro-cement.” Ferro-cement consists of several layers of fine steel mesh sprayed with a cement mortar. For heavier uses, it sometimes has reinforcing rods between the mesh layers. Ferro-cement is very thin slightly thicker than the mesh itself and its great strength and elasticity make it ideal for constructing thin shells and slabs. Since the mortar can be sprayed directly onto the mesh, structures can often be built of ferro-cement without the use of forms. In cases in which Nervi did use forms, he made them of ferro-cement instead of wood, thus giving him greater flexibility in shaping cast concrete pieces.

In the late 1940’s, Nervi was faced with a new challenge: to build Salone B, 243 feet by 310 feet, for the Turin Exposition Hall of 1948-1949. Again, Nervi’s was the most economical proposal submitted. He had only eight months in which to complete the building, and he used ferro-cement to help him meet that demanding schedule. To form the roof vaulting, he made prefabricated sections of corrugated ferro-cement, which were then lifted into place. The troughs and peaks of the corrugated pieces were then filled with cast-in-place reinforced concrete to form integral ribs the main load-bearing structural members. Thus, the roof vaulting was a combination of ferro-cement and reinforced concrete.

For the half-dome at one end of the hall, Nervi introduced another innovation. He used precast, panlike units made of ferro-cement, which created troughs between them when laid side by side. The units had been cast in concrete molds, which had been built from a model of the half-dome. The precast units, in the shape of diamonds, were then lifted into place and supported by scaffolding while the roof was completed. Into the troughs between the units, Nervi laid reinforced concrete to form the supporting ribs of the half-dome. Thus, the reinforced concrete ribs together with the precast units formed the entirety of the half-dome. Nervi also used this system on Salone C of the Turin Exposition Hall and later on a number of other domes, vaults, and ceilings. In addition to being light, strong, and easy to build, the crossing ribs and diamond-shaped panels created a pleasing visual effect.

In addition to his busy schedule with these and other projects, Nervi began teaching in 1947. He joined the faculty of architecture at the University of Rome and remained there until 1961. During the academic year 1961-1962, he was the Charles E. Norton Professor at Harvard. Nervi’s diligence allowed him to maintain this demanding schedule. He always started work promptly at 8:30 a.m. and only took time out to teach or to visit one of his building sites.

In 1952, Nervi devised yet another construction technique for use in building the Tobacco Factory in Bologna. The five-story building was to be large in measure and thus represented a significant challenge. Nervi once again won the design competition on the basis of the great economy of his design, which was, in turn, based on movable forms. Avoiding a costly timber framework, Nervi made ferro-cement forms that resembled inverted rectangular pans. The forms rested on wheeled scaffolding that could be raised and lowered by hydraulic jacks. The troughs between adjacent forms created strengthening ribs in the floor, when filled with cement. After the concrete pillars for a given floor were in place, the builders raised the ferro-cement forms into place and poured the reinforced concrete floor on top of them. Once the concrete had hardened sufficiently, the builders lowered the forms and wheeled them to the next bay. Nervi carried this time- and money-saving technique one step further in the Gatti wool factory in Rome. In this building, the forms were shaped so as to locate the strengthening ribs along the lines of greatest stress. This technique added to both the efficiency and the beauty of the building.

The 1960 Olympics in Rome created for Nervi the opportunity to achieve some of his most spectacular structural engineering but not at the cost of aesthetics. Nervi designed three structures for the Olympics: the Palazzetto dello Sport, the Palazzo dello Sport, and the Stadio Flaminio. The Palazzetto, though smallest, has perhaps the strongest impact from both inside and outside. The flute-edged roof of the Palazzetto was constructed in typical Nervi style. He used precast, diamond-shaped units to form the shell of the roof. As in some of his earlier structures, these pieces were joined by cast-in-place ribs that gently curved outward from the center in left- and right-handed curves, thus intersecting to create the diamond pattern. The ceiling’s visual effect was one of a light and elegant webbing. The ribs carry their load to Y-shaped buttresses, which also carry the line of the shell to the ground. The outside view of the larger Palazzo is spoiled, however, by a gallery all the way around it that conceals the lines of the structure. Inside, however, Nervi created a much different look from that in the Palazzetto by using precast, corrugated sections (resembling those in the Turin Exhibition Hall) that radiate out from the center. As in the Turin Exhibition Hall, he filled the troughs and peaks in the corrugation with cast-in-place concrete. Although the outside surface of the corrugations have been covered to create a smooth surface, the inner view is quite striking.

Pier Luigi Nervi received many honorary degrees and awards during his lifetime, including honorary membership in the American Academy and National Institute of Arts and Letters (1957). He died at the age of eighty-seven in his home in Rome.

Significance

The two primary motivating factors in Nervi’s designs were economy and art. He produced his first major work during the Great Depression and remained quite busy throughout World War II and after. The resultant search for economy not only won many design competitions but also produced new construction techniques and forms. His concern for art probably stemmed from his upbringing in Italy and his consciousness of the many beautiful structures to be found there.

Nervi achieved his desired economic and aesthetic ends largely through the repeated use of three structural elements: precast corrugated beams, precast ceiling panels, and ferro-cement. Using these elements in combination with his own techniques (such as forms on movable scaffolding), Nervi avoided the use of expensive timber forms and framework, speeded construction time, and gave himself much freedom in shaping the lines of a structure. In the process, he also created very light but strong roof spans, enclosing and beautifying large indoor spaces. By always striving for economy and beauty, Nervi reached a high point in building with concrete. Although trained as an engineer, he did not let mathematics and scientific theories dominate his work. Through his buildings, he proved that structure can be art.

Bibliography

Huxtable, Ada Louise. “Geodetic and Plastic Expressions Abroad.” Progressive Architecture, June, 1953, 111-116. This brief article summarizes Nervi’s contributions to the field of structural engineering, emphasizing ferro-cement. It also summarizes some of his most important works (as of 1953) and illustrates one of his hangars, the Gatti wool factory, and Salone B of the Turin Exposition Hall.

‗‗‗‗‗‗‗. Pier Luigi Nervi. New York: George Braziller, 1960. Part of the Masters of World Architecture series, this short book provides a concise, yet thorough account of Nervi’s life, work, and place among the world’s architects. Roughly one-half of the book is devoted to photographs and drawings of his major works, both in progress and completed. The book contains a complete list of his works and bibliographies of books and articles written by and about him.

Margolis, Ivan. Architects Plus Engineers Equals Structures. Chichester, England: Wiley Academy, 2002. Describes the union of architecture and engineering, analyzing the work of Nervi and other architect-engineers.

Nervi, Pier Luigi. Structures. Translated by Giuseppina and Mario Salvadori. New York: F. W. Dodge, 1956. In this book, Nervi explained in his own words, clearly and simply, the principles behind the structures that he built. He also pointed out why he thought beauty was unavoidable in finding a solution to structural problems. The reader will also find discussions of the role of economy in design, the advantages and behavior of reinforced concrete, and a separate chapter on ferro-cement (with photographs of several boats that Nervi built with hulls of ferro-cement).

‗‗‗‗‗‗‗. The Works of Pier Luigi Nervi. Translated by Ernest Priefert. London: Architectural Press, 1957. With a preface by Nervi and an introduction by Ernesto N. Rogers, this is probably the best illustrated book available on the work of Pier Luigi Nervi. The bulk of the volume (almost 140 pages) consists of black-and-white photographs and line drawings of Nervi’s works. Useful explanatory notes accompany many of the illustrations.

“Pier Luigi Nervi.” Architectural Forum 99 (November, 1953): 141-148. This article highlights Nervi’s structural innovations precast corrugated beams, precast ceiling panels, and ferro-cement forms and then illustrates their use in Nervi’s projects.

Smith, G. E. Kidder. Italy Builds: Its Modern Architecture and Native Inheritance. London: Architectural Press, 1955. This work begins with a brief and very general overview of the influences in Italian architecture. The remainder of the book is then devoted to a discussion of modern architecture in Italy. Most of Nervi’s major works, as of the date of publication, are included. Reasonably well illustrated; includes an index and a useful bibliography.