pier luigi nervi's works for the 1960 rome olympics

Pier Luigi Nervi designed and constructed four struc-tures for the 1960 Rome Olympic games: three sportsfacilities and a viaduct serving the Athlete’s residentialquarter, the Villaggio Olimpico. These are consideredsome of his most famous international works.

– The Palazzetto dello Sport (Small SportsPalace; 1956–57; with Annibale Vitellozzi) inthe Flaminio area of Rome is characterized byits sixty-meter diameter dome, which is heldup —or better, held down— by 48 radial Y-shaped struts whose divergent upper arms de-velop the rim «decoration». The externallysmooth dome only reveals its large rhomboidalribbing internally.

– The Palazzo dello Sport (Sports Palace;1956–59; with Marcello Piacentini) in theEUR area is also dome-shaped, but with a hun-dred-meter diameter. The internal surface ischaracterized by minute pleated V-shaped«waves». Externally, the dome is concealed bya high glass cylinder, which only partially re-veals the structure of the perimetral stands.

– The Stadio Flaminio (Flaminio Stadium;1956–59; with Antonio Nervi) is characterizedby the numerous moulded frames, upholdingthe slim ridged canopy covering the grand-stand, which vary in width along the oversailand completely flatten out along the rim;

– The Corso Francia Viaduct (1958–60), alsoin the Flaminio area, is characterized by

varying width pillars —the sections changefrom rectangular to cross-shaped and thetransitional surface from one to the other in ahypar surface, formed by straight lines— andby the V-shaped beams, precast and pre-stressed.

The works erected for the 1960 Olympic gamesrepresented a crucial milestone in Pier Luigi Nervi’scareer. They are the best examples of his experimen-tation on statics, construction and architecture, andguaranteed his international fame. However, the ob-

Pier Luigi Nervi’s Works for the 1960 Rome Olympics

Tullia Iori, Sergio Poretti

Figure 1Small Sports Palace, Rome 1956–57. Aerial view. (Fotote-ca, Roma)

Actas del Cuarto Congreso Nacional de Historia de la Construcción, Cádiz, 27-29 enero 2005, ed. S. Huerta, Madrid: I. Juan de Herrera, SEdHC, Arquitectos de Cádiz, COAAT Cádiz, 2005.

jective of this paper is not to illustrate the architec-tural or typological features of these works, whichare already well known. The true aim is to showcasethose features that made Nervi’s works clearlyunique and understand the reasons, which made hisdistinctive method of reinforced concrete construc-tion bloom in post-war Italy. Nervi was sixty-nineyears old when he completed these four structures.He only took four years (from the end of 1956 to theearly months of 1960) to erect them. Moreover, hewasn’t solely focused on the projects. Nervi’s ownconstruction company, the Soc. An. Ingg. Nervi &Bartoli (practically a family-run business) staffed allfour building sites. Nonetheless, the works were exe-cuted with great speed and all four structures werecompleted in 12 to 18 months. All of these works

clearly display Nervi’s imprint and global paternityfrom the design to the construction. How did he ac-complish this? What came to be known as the «NerviSystem» was the result of a twenty-year-long intenseand complex experimentation on statics and con-struction aspects. The deserved results are showcasedby the four Roman structures.

During the twenty years preceding the Olympics,Nervi had devised a new building material, «ferroce-mento», and a unique construction process, structuralprefabrication, which allowed him to face the simul-taneous construction of four such imposing projects.Therefore, in order to investigate the genesis of theOlympic works, it is necessary to step back in time tothe late 1930s.

THE INVENTION OF FERROCEMENTO

AND STRUCTURAL PREFABRICATION

The stimulus to experiment was brought about by theparticular economic situation, Autarchy, whichreigned in Italy at the time. Mussolini was preparingfor war and wanted Italy to become economically in-dependent from other European countries. Self-suffi-ciency, however, was particularly complicated due tothe dearth of raw materials present on the nationalterritory. The construction industry, therefore, wasthe first to feel the consequences. Steel was amongthe materials, normally imported from abroad, whichwas suddenly rationed. (In any case, steel was re-served for military needs).

Reinforced concrete, which requires steel for thereinforcement, suddenly became an anti-autartic andanti-national construction material. Notwithstandingthe fact that reinforced concrete was the most wide-spreadly used material in both small and large-scaleconstruction work, in 1939 its use was banned.

So what could designers and constructors using re-inforced concrete do (and Pier Luigi Nervi was oneof the most important figures in both categories)?Hoping for better times, they began experimentingalternative solutions. In the ordinary building indus-try, experimentation concentrated on the substitutionof steel reinforcement with other materials foundthroughout Italy, such as aluminum, wood, bamboo,etc. In large-scale constructions, instead, attemptswere made to minimize the use of steel by optimiz-ing the performance of other materials, while hopes

606 T. Iori, S. Poretti

Figure 2Small Sports Palace. The dome from the interior (Nervi1963)

focused on the discovery of a more efficient mannerfor the use of steel and concrete. Pier Luigi Nerviconducted such experiments (as well as, for example,Riccardo Morandi, who at this time began to discov-er the potential of prestressed concrete).

Nervi carried out a detailed analysis of every sin-gle construction cost. He became an expert in calcu-lating the incidence of every steel rod, every bag ofcement, every wooden plank, every liter of petrolused for transportation on the global cost of erectinga structure. This allowed him to evaluate the mosteconomical structural solution for every detail in theconstruction plan. (This meticulous analysis exclud-ed two parameters, the cost of labor and design, bothof which were considered to hardly amount to any-thing). Nervi’s analysis led him to focus on two fun-damental points. The first was that in order to saveon steel it was fundamental to reduce the use of ce-ment: thin layers of densely reinforced concrete aremore efficient —and therefore more inexpensive—than larger bodies of concrete with less reinforce-ment. The second was that reducing the use of wood-en casting moulds for directly erecting elementsproved to be the most important cutback. These sim-ple reflections gave rise to two parallel activities.First, Nervi began experimenting with slender con-crete slabs densely reinforced with steel; secondly,he started an important experimental building yard inwhich he significantly reduced the need for wood,which was becoming exceedingly scarce, by makinguse of prefabricated on-site concrete elements. The

experiments conducted on the densely reinforcedconcrete slabs were hardly scientific. They were veryartisanal and conducted in chance labs, often in hishouse. (There even are accounts that state that Nerviconserved these experiments on his balcony). Nerviwas only able to rely on load tests much later, whenthey were carried out in the Milan Polytechnic labo-ratory headed by Arturo Danusso.

How were these slabs, which Nervi first referredto as being «evenly reinforced» and then «ferroce-mento slab», made? Nervi superimposed various lay-ers of metal netting formed by small diameter (1 mmor less) steel wire. He then pressed mortar made ofcement and sand (but no gravel) into the metallicmesh using a trowel or float This operation was con-ducted on one side of the mesh until the cementemerged from the other side after having saturated it.Naturally, the operation also depended on the plastic-ity of the mortar, which had to be accurately pre-pared. Both horizontal and vertical slabs could bemade in this manner and they did not require woodenmoulds to shape the mortar until it hardened.

The extreme subdivision and the uniform distribu-tion of the reinforcement in the concrete created amaterial that was different from ordinary reinforcedconcrete. The new material, called «ferrocemento», isa homogeneous, isotropic, elastic material and resistsboth traction and compression (Nervi 1943). Nervi

Pier Luigi Nervi’s Works for the 1960 Rome Olympics 607

Figure 3Sports Palace, Rome 1956–59 (Nervi 1965a)

Figure 4Sports Palace: the dome from the interior (Nervi 1965b)

patented his invention in April 1943, when Italy wasstill at war. In July 1943, when the Fascist regimecollapsed and the Nazi forces occupied Rome, Nervirefused to collaborate and closed his building compa-ny (Rome would not be liberated until June 1944). Inthe meantime, Nervi continued to experiment withwhat he called «structural prefabrication». This tech-nique, which involved the use of prefabricated ele-ments, allowed him to dramatically reduce the use ofwood from his building sites. The opportunity to em-ploy his new construction methods was provided bythe construction of the famous series of airplanehangars for the Italian Air-Force: six identicalhangars were created in pairs in Orvieto, Orbetello,and Torre del Lago between 1939 and 1942.

Nervi adopted the same structural plan he had em-ployed in Orvieto in 1936, but abandoned the com-plex and expensive wooden moulds that he had need-ed to erect the great ribbed vault. How was thisdone? Nervi divided the ribs into as few small andidentical elements as possible. These individual ele-ments were prepared in series in moulds that couldbe reused dozens of times. The elements were thenlifted into place by using a light scaffolding systemand joined with concrete pour. Once the work wascompleted, there was no trace of this fragmentationand the resulting structure proved to be staticallymonolithic. In November 1939, this procedure wasprotected by a patent. Nervi was aware that he haddevised a system that could be applied to any type ofconstruction. All it required was an efficient de-com-position of the structure into a few types of elementsthat could then be pre-fabricated. Thus, by the end ofthe war, Nervi possessed a new material, «ferroce-mento», and a new building technique, structural pre-fabrication. Ferrocemento is a light material com-posed of layers of steel mesh grouted together withcement (which can still be found in natural depositsthroughout Italy) and sand. An unspecialized laborercan easily prepare it with very simple equipment(trowel, float, etc.). It was cheap and perfect for post-World-War-II Italy.

Structural prefabrication is an artisanal techniquethat requires accurate planning, but can easily be im-plemented on a traditional building site as it does notrequire specialized labor. What Nervi invented wasnot factory-made serial construction elements, butthe application to individual building of serial ele-ments pre-fabricated directly on the building site.

Notwithstanding the pompous name, prefabrication,this really is an age-old technique applied on the ba-sis of available means and materials. Just as in thepast, columns, capitals, metopes, triglyphs and ash-lars were carved on the building site and then erectedinto their permanent position; Nervi’s constructionelements were constructed on the site and then erect-ed into position. It was a perfect technique for build-ing yards in post-war Italy without either specializedlabor or machinery.

THE NERVI SYSTEM

In the period between the liberation of Rome and theOlympic games, Nervi had many opportunities to testhis inventions. First, separately with the famousMagliana hangar and then together in a series of mi-nor experimental construction jobs. However, the bestprospect to test both together was provided by theconstruction of Hall B of the Turin Fair. During theextremely rapid construction of this building (begunin September 1948 and completed in April 1949),Nervi was able to perfect all the construction process-es that he would use in the future and which came tobe known as the «Nervi System». The four structuressimultaneously constructed for the Olympic gamesprovided the opportunity for the definitive fine-tuningof the Nervi System. Their analysis, in fact, allows usto understand the system itself, and how ferrocementoand pre-fabrication were combined.


Figure 5Flaminio Stadium, Rome 1956–59. The covered grandstand(Nervi 1965b)

In designing these facilities, Nervi opted for rathertraditional architectural solutions and showed a clearpreference for symmetrical curved forms. However,Nervi’s domes and vaults are clearly discerniblefrom classical examples on account of their complexsurfaces. Nervi created extremely detailed ridged,wavy, pleated and ribbed surface areas. His struc-tures are enriched by a minute superficial design thatis not found in any other contemporaneous rein-forced concrete structures. The surface depths are of-ten no thicker than 3 cm, but the complexity of themovement prevents one from perceiving its slender-ness, which can only be discovered by consulting theexecutive plans.

Why did Nervi adopt such complicated surfacesthat had been abandoned by others due to the con-struction and calculation problems they entailed?Why were these complex superficial combinationsreserved for symmetrical and even circular struc-tures? The answer lies in the peculiarity of Nervi’sbuilding sites. Nervi’s concept of structural prefabri-cation meant that structures had to be de-composedand the separate elements had to be prepared aheadof time. So, every element had to be small and lightenough to be lifted and easily set into place. Theslenderness of each section was functional not onlyin terms of weight, but also helped streamline materi-al costs and the minute superficial design dependedon the scale of the prefabricated elements. Eachpiece had to have a shape, which would allow it to berigid enough to resist the handling and erectingstress. Finally, each piece had to be replicable as

many times as possible. This meant that only transla-tion and revolution surface designs were feasible.

How was structural prefabrication adapted to thestructures erected for the Olympic games? What wasthe de-composition principle adopted? The sphericalvault of the Palazzetto dello Sport is composed of atotal of 1.620 elements, but only 19 different types ofthem (12 rhomboidal elements of varying shapes and1 anomalous piece for the apex were repeated 108times, while the 6 elements for the edge were repeat-ed 36 times). The spherical vault of the Palazzo delloSport, instead, is formed by 1.008 elements of only 9different types (6 V-shaped ashlars forming 144identical waves and 3 for the 48 fan-shaped ele-ments). The Stadio Flaminio canopy and grandstandstands are even simpler in conception: a single iden-tical piece was repeated dozens of times. The sameholds true for the floor system of the Viaduct.

The elements were prepared directly at the site andstacked, while the parts that needed to be cast-in-place were created. (Naturally, there still were plentyof these: from the foundations to the pillars). Subse-quently, the elements were set into place by usingscaffolding. The double purpose of restablishing themonolithic nature of the whole and completing theresisting system was obtained with cast-in-place ribs.


Figure 6The Corso Francia Viaduct, Rome 1958–60 (Nervi 1963)

Figure 7Small Sports Palace: view during construction of the dome(Nervi 1965a)

One of the most interesting aspects of the Nervi Sys-tem is the skillful combination of prefabrication andcasting.

What element types were adopted to de-composethe complex structures? In which parts was «ferroce-mento» used?

The complexity of the surface, the minute designof the ribbing, the thick pleating of the domes andfloors was obtained, albeit with different results, byemploying only two different types of «special» ele-ments made with «ferrocemento», the «wave ele-ments» and the «rhomboidal elements», which Nervihad invented at the Turin site. The «wave elements»,patented in August 1948 (Nervi 1948), were meant togive prefabricated sections a geometrical design thatwould guarantee an elevated moment of inertia witha minimum use of material. The use of «ferrocemen-to» made this technique economical. It was just amatter of bending the wire mesh with a brick mouldand then filling the mesh with mortar as usual. Theresult was a light (about 1.500 kg every 4 meters)construction element no thicker than a few centime-ters, and resistant to transport due to its elevated mo-ment of inertia. The «wave elements» are closed ateither end by non-deformable headers and their rigid-ity is ensured by two or three internal diaphragms,

which keep the slender walls (often lightened bywide apertures) from deforming. When the elementsare mounted on the falsework, their shaping allowsthe casting of concrete ribs both along the top andthe bottom of the wave. The reinforced ribs are con-nected to the precast element via the reinforcing rodsleft protruding from the element itself.

The «wave elements» used in the dome of thePalazzo dello Sport are made up of V-shaped ele-ments that vary between 4 and 5 meters and havelarge side apertures with perforated diaphragms to al-low the passage of the lighting system and other in-stallations. The V-shape motif is also repeated in thebeams that form the road bed of the Corso FranciaViaduct. These, however, are 16 m long and partiallypre-compressed. In the canopy covering the grand-stand at the Stadio Flaminio, the 15 m oversail wasobtained by juxtaposing variable geometric wavesalong it. In this case, the casting is limited to theridge of the wave and joins the prefabricated ele-ments to the previously erected structure.

The other special element, the «rhomboidal ele-ment», was patented in May 1950 (Nervi 1950). Theidea sprouted from the need for a thin curved sur-face stiffened by ribs, which is very complicated tocast. Nervi solved this problem by inventing a spe-cial type of formwork, a precast «shape-element»,no wider than a few centimeters, which would not


Figure 8Italian patent n. 445.781 by Pier Luigi Nervi, «Procedimen-to costruttivo per la realizzazione di strutture cementizieondulate o curve con o senza tensioni preventive», August26th 1948: the «wave element» (Archivio Centrale delloStato)

Figure 9Flaminio Stadium: placement of one of the canopy ele-ments (Nervi 1965b)

be dismantled, but became an integral part of thecompleted structure. «Shape-elements» must be geo-metrically exact parts of the surface to be created.This can easily be done by creating a surface modelreplicating the exact surface to be erected. Thewooden model is used to prepare the moulds in ce-ment, plaster or wood, which are then used to makethe entire series of «shape-elements». Naturally, thistechnique is economically sound only if the samemoulds can be utilized for hundreds of pieces. Theshape-elements are shaped so that once they are seton the scaffolding, they generate a channel (closedunderneath) in which the stiffening rib can be cast-ed. A thin slab can also be poured in place over thewhole surface.

Precast «rhomboidal elements» were employed tocreate the entire dome of the Palazzetto dello Sport.The 12 types of elements all have the same thickness(2,5 cm). They were prefabricated in series by usinga mould created with a model. Once these elementswere mounted on the scaffolding, only resting on 2points, the reinforcement was placed in the channelsand the cast was executed. The reinforcement alsoextends to the extrados of the dome where a 3 cmthick layer of concrete was cast. The same techniquewas also used for the intrados of the ring gallery inthe Palazzo dello Sport. Here, too, a model was usedto prepare the moulds in 6 different measures used toprefabricate the required 240 elements. This stillleaves us curious regarding a central point: How didNervi’s dome function statically? Do the thin «ferro-cemento» elements support the load or is this accom-

plished by the more consistent cast ribbing? Do thewaves and rhomboidal elements serve a structuralfunction or did they only serve as casting moulds? Inhis papers, Nervi declared that they served both pur-poses: the domes attain stability both as membranesand as a series of rib-arches. Certainly these struc-tures are deeply hyperstatic and it is practically im-possible to comprehend exactly how the dome settledconsidering that its elements were created at differenttimes and underwent different shrinking, aging andstress processes during their erection.

RECONSTRUCTION MONUMENTS

The analysis of the Olympic works confirms theoriginality of Pier Luigi Nervi’s experimentation.Their originality lies especially in the unique tech-nique, which was employed to construct them. At thetime, in fact, many engineers around the world wereexamining the issue of thin shell concrete structuresfollowing the pre-war experiments conducted byDischinger, Finsterwalder, Torroja, Freyssinet, Ai-mond and Lafaille. Other works under scrutiny in-cluded those by Felix Candela and Heinz Isler, whobecame famous at the end of the 1950s. They alsoemployed thin sections and took advantage of resis-tance through shape.


Figure 10Sports Palace: placement of a V-shaped element for thedome (Nervi 1965a)

Figure 11Italian patent n. 465.636 by Pier Luigi Nervi, «Procedimen-to costruttivo per la realizzazione di superfici resistenti pi-ane o curve costituite da reticolati di nervature in cementoarmato, completate o meno da solette di collegamento tra lenervature», May 19th 1950: the «rhomboidal element»(Archivio Centrale dello Stato)

However, Nervi’s domes and vaults were not onlythe result of a new invention in reinforced concreteconstruction, but also profoundly related to post-warItaly. Italy lagged far behind in the technological ad-vances that had been achieved in construction work.During the phases that led from Autarchy to war, andthe long and difficult years of the post-war recon-struction, the Italian construction industry remainedunaltered. It was both technologically and industrial-ly behind, had no specialized labor or machinery,and was controlled by small, improvised firms.

Nervi’s works certainly reflect this condition in thepoverty of means and the artisanal nature of thebuilding sites. Nonetheless, his works remain master-pieces of structural engineering and their sophisticat-ed and bold solutions became the symbol of Italy’srebirth. They were true monuments to the reconstruc-tion effort.

Nervi was certain that his system demonstratedthat the full potential of reinforced concrete still hadto be discovered. He believed that his work wouldusher in a new phase of reinforced concrete construc-tion. However, as we now know, the exact oppositetook place. The use of thin shell concrete structureswas progressively abandoned and «ferrocemento»—an economic miracle— remained exclusively asso-ciated to Nervi.

Thus, Nervi’s work did not trigger further experi-mentation, but rather closed the age of the great rein-forced concrete structures. Why? First and foremost,the inexpensive nature of «ferrocemento» and arti-sanal prefabrication was brought to an end by thegrowing costs of labor and materials. However, whatbecame even more anachronistic was the idea that asingle person could control the entire constructionprocess. The great designer and site director was thelast heir of a long dynasty of Italian constructors thatfrom Antonelli and Vittone all the way back toBrunelleschi had created many masterpieces. Thisparticular placement in the history of engineeringdoes not in any way diminish the great influence thatNervi’s works had on the architectural culture andproduction of the twentieth century. Nervi’s influ-ence affected architectural experimentation in gener-al, rather than the evolution of great structures (infact, Nervi has always fascinated architects more sothan engineers). Thus, Nervi’s works for the 1960Rome Olympic games decisively influenced the de-velopment of structural expressionism, which char-acterized the architectural languages of Italy in theyears to come.

REFERENCE LIST

Budinis, M. 1958. I nuovi impianti per le Olimpiadi aRoma. Quaderni della Società generale Immobiliare 7:1–7.

Desideri, Mario. 1980a. Sul calcolo delle cupole a nervaturemeridiane. La volta del Palasport a Roma. L’industriaitaliana del Cemento 6: 433–440.


Figure 12The Corso Francia Viaduct: the positioning of a beam on asupport (Nervi 1965b)

Figure 13Small Sports Palace: piled «rhomboidal element» (Huxtable1960)

Desideri, Mario. 1980b. Nervi e la tecnologia del ce-mento armato. L’industria italiana del Cemento 10:869–886.

Desideri, P.; P. L. jr Nervi and G. Positano. 1979. Pier Lui-gi Nervi. Bologna: Zanichelli.

Heimsath, Clovis B. 1960. Nervi’s methodology. Architec-tural forum 2: 138–143.

Huxtable, Ada Louise. 1960. Pier Luigi Nervi. Milano: IlSaggiatore.

Nervi, Pier Luigi. 1943. Perfezionamento nella costruzionedi solette, lastre e altre strutture cementizie armate. Ital-ian patent n. 406.296.

Nervi, Pier Luigi. 1948. Procedimento costruttivo per la re-alizzazione di strutture cementizie ondulate o curve cono senza tensioni preventive. Italian patent n. 445.781.

Nervi, Pier Luigi. 1950. Procedimento costruttivo per la re-alizzazione di superfici resistenti piane o curve costituite

da reticolati di nervature in cemento armato, completateo meno da solette di collegamento tra le nervature. Ital-ian patent n. 465.636.

Nervi, Pier Luigi. 1963. Nuove strutture. Milano: Ed. diComunità.

Nervi, Pier Luigi. 1965a. Aesthetics and Technology inBuilding. (The Charles Eliot Norton Lectures, 1961–1962).Cambridge: Harvard University Press.

Nervi, Pier Luigi. 1965b. Costruire correttamente. Carat-teristiche e possibilità delle strutture cementizie armate.Milano: Hoepli.

Perilli, Achille. 1958. Pier Luigi Nervi. Civiltà delle Mac-chine 2: 30–31.

Pica, Agnoldomenico. 1969. Pier Luigi Nervi. Roma: Edi-talia.

Vaccaro, Giuseppe. 1958. Il palazzetto dello Sport, a Roma.L’architettura. Cronache e storia 27: 584–593.


pier luigi nervi's works for the 1960 rome olympics

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