Artisanal Prefabrication - Nervi's Palazzetto

I
ARTISANAL
PREFABRICATION
Nervi’s Palazzetto

II III
CONTENTS
1 INTRODUCTION p. 6

2 AUSTERITY & EXPERIMENTATION
2.1 Autarchic Concrete p. 12
2.2 Hangars p. 22
3 INVENTION & IMPLEMENTATION
3.1 Occupation: Ferro-Cement p. 28
3.2 Reconstruction Opportunites p. 38
3.3 Turin Exposition p. 44
4 PALAZZETTO
4.1 Works for the Rome Olympics p. 58
4.2 Palazzo Dello Sport p. 62
4.3 Palazzetto Dello Sport p. 68
5 CONCLUSION p. 84
BIBLIOGRAPHY

Books p. i
Articles p. iii
Web p. v
Media p. vi
Personal Communications p. vii
IMAGE CREDITS p. viii

APPENDIX
Nervi Patents p. ix
George Hintzen
University of Westminster
Diploma in Architecture
2011/12
130049015

Artisanal Prefabrication: Nervi’s Palazzetto
6 7
1
Introduction
By the 1960 Rome Olympics, Italian engineer Pier Luigi Nervi had reached the pinnacle of his career. Through a
rigorous program of research and forty-one patents protecting his procedures, Nervi had made crucial innovations
in reinforced concrete construction that allowed him to succeed despite Italian autocracy and austerity and deliver
a vast volume – over one thousand – and variety of projects. His empiricism and the artisanal construction site that
he cultivated allowed close observation and control of production, by fostering a rapport with his workforce and
materials which led to crucial gains in speed, economy and quality.
Nervi challenged the notion that unconventional construction would be economically prohibitive. His innovative
construction method, the Nervi System, discovered through experimentation in the late 1930s and used in
subsequent applications in the late 1940s crucially combined processes of Structural Prefabrication and the
material of his own invention: Ferro-Cemento - a light, resilient reinforced concrete – and so became standard
technology in his practice. His control of the building process exceeded construction and structural motives and he
was able to use it to display a convincing synchronicity between aesthetics and structure.
The emergence of engineering and new materials – steel and reinforced concrete - led to a culture of
experimentation with emergent forms and methods of construction. Concrete’s plasticity and ‘formless’
possibilities naturally enthused an exclusive set of thin-shell ‘Master Builders’, who were particularly suited to
explore the limits of structural performance through intuition and experimentation, enabling them to pursue
enclosures with graphically incalculable curvatures. This dissertation will examine how Nervi’s engineering ability
coupled with his relationship to the building industry and wider socio-economic conditions led to a particularly
innovative construction typology: long-span prefabricated shells.
The Palazzetto Dello Sport for the 1960 Olympics was this typology’s finest expression and so too of Nervi’s ideals.
While it was by no means the end of his career, it marked an important change in direction and the end of an era.

8 9
1 | Introduction
His fame following exposure on the international stage made him globally sought-after, and he undertook projects
abroad, leading to a loss of control over the design and construction processes, and dilution of his formula and
invention. He lost the expressiveness achieved through economy and prefabrication, and succumbed to larger,
monolithic projects abroad, forced towards the cumbersome, classical stereotomy that he had sought so long to
eliminate.
Excursions in the Summer of 2011 to the edifices themselves by way of an arranged private tour of Nervi’s Turin
Exposition by Christiana Chiorino – co-curator of a recent Nervi exhibition there – and a personal visit to the
Palazzetto in Rome confirmed the structure’s complexities and magnetism, and my interest therein. This was
further elucidated shortly afterwards by appointments to view the Palazzetto’s drawings at the CSAC archive in
Parma and construction photographs thereof at the MAXXI museum’s archive in Rome.
Primary archival material such as construction photographs and drawings, coupled with Nervi’s monologues
and manifestos allude to his processes and reveal his concerns with Costruire Correttamente - Building Correctly.
Nervi glorified the artisanal construction site, and his structural theses and lines of force became an expression
and embodiment of the labour contained therein, particularly in his unique prefabricated enclosures and is most
succinctly presented in the Palazzetto.
Nervi is a rare designer whose work is discussed in terms of his structural and technical innovation; the
investigation initially sought to make sense of this interest and the reasons for and mechanics of his peculiar
production, which although alluded to, is often perfunctorily mentioned in context of their architectural effect.
Using a critical selection of his experimentation and architectures as generational milestones that - defined by his
milieu - trajected the evolution of his specific artisanal constructive typology, particularly the prefabrication of
thin-shell reinforced-concrete structures; a journey of innovation that led to the finest demonstration of his ideals
and proprietary techniques: the Palazzetto Dello Sport.

12 13
Pier Luigi Nervi was born on 21st June 1891 in Sondrio, an Alpine town in the North of Italy. His father was an
official at the Post Office, and he and his 2 sisters spent their youth in several cities in Italy, in a rigid middle-
class, turn-of-the-century upbringing. At the age of seventeen and with an interest in aviation, Nervi attended a
five-year course at the Royal School of Architecture and Engineering at The University of Bologna, and on 28 July,
1913, graduated with a Civil Degree in Engineering. Reinforced concrete construction had recently become part
of the professional training of engineers, and basic procedures and standards for its application were published,
equipping graduates with the information necessary to safely apply the systems. However, technical procedures
and calculation were provided alongside but as distinct to a humanist approach at separate artistic and polytechnic
faculties. Nervi later remarked “When I studied at the excellent Civil Engineering School at Bologna, the world
architecture referred only to the study of facades and of their details. It never occurred to our professors, or even
to us, that a bridge, a carrying structure...could also be works of architecture”1
, an idea of false formalism that
emphasised “the division between substance and appearance...the mentality of the decorator, to which everything
is possible in the field of mouldings and plastic and pictorial decoration...[with an] ignorance of the physical entity
of architecture.”2
Two main figures influenced him here: Professor Silvio Canevazzi, who ‘fostered his awareness
of both of the importance of theoretical and experimental calculations’ and Professor Attilio Muggia, whose broad
professional experience provided him with the ‘essential basis for a perfect synthesis of design and construction,
made possible through the mastery of building techniques’3
.
In 1913 Nervi immediately joined the SACC, Società Anonima per Costruzioni Cementizie in Bologna (fig. 2.1),
under the guidance of former Professor Muggia, who held the rights for the use in Italy of the 1892 patented
‘Hennebique System’. This crucially integrated separate elements of reinforced-concrete construction into a single,
monolithic element, and fundamentally changed structural conception. This was crucial to fostering Nervi’s
1. Huxtable, A. L. 1960. Pier Luigi Nervi (New York: George Brazilier, Inc.), p21.
2. Nervi, P. L. 1956b. Unpublished Manuscript, p.45.
3. Olmo, C & Chiorino, C. (eds.). 2010. Pier Luigi Nervi – Architecture as challenge (Milan: Silvana Editoriale Spa), p. 201.
2
Austerity & Experimentation
2.1 Autarchic Concrete

14 15
affinity with reinforced concrete and allied him from an early stage to the material to which he remained faithful
with growing regard and affection. The company, like many others, gradually replaced traditional materials
with concrete, which proved to be faster and more economical, but preserved an architectural classicism and
eclecticism. The years between 1850 and 1900 saw various influential international experiments using speculative
concrete technologies in France, Germany, the UK, and to a lesser extent in the United States due to dependence on
imported Portland Cement4
. But a systematised application of modern reinforced-concrete technique is credited to
Francois Hennebique, a French building contractor who ’conducted a private program of research before patenting
his own uniquely comprehensive system in 1892’.5
(trend of experimentation-source?) Initially conceived as a
fire-proofing system for iron-framed construction, the composite system addressed the problem in reinforced
concrete of the provision of a monolithic joint, which Hennebique overcame through the use of cylindrical-
section reinforcement - which could be bent round and hooked together - and the use of stirrups to bind joints
and resist local stresses6
. A shrewd entrepreneur, by 1902 Hennebique had international license agreements for
his innovative patent and more than 7,200 European structures7
had been completed using it. Starting his career
as a stonemason, Hennebique, like Nervi ‘never quite escaped his artisanal background, and his work shows
[similar] characteristics…a drive for lightness, a distaste for calculations, and a growing self-confidence as his
experience widened.’8
Fertile years of experiment since the mid nineteenth century, particularly in France and
Germany, had led to the incarnations of various speculative concrete technologies by number of entrepreneurial
builders and engineers – much like Nervi - who had been conducting research and promoting their reinforced-
concrete construction systems. But it was Hennebique’s patent that would encourage widespread ‘systematic
experimentation’9
, aided significantly by exposure at the 1900 Paris Exhibition. Reinforced concrete had ‘come into
its full majority in the first decade of the twentieth century’10
. However Nervi insisted he only became fully aware
of the structural experiments of Perret, Maillart, Freyssinet and others at a much later stage, and that his personal
expression developed partly because of his cultural isolation. Itlay had suffered from slow industrialisation, and
had failed to participate in early experiments of concrete construction, but benefitted greatly from the diffusion of
the Hennebique System: ‘the importation of foreign systems and newly industrialised production of cement led to
widespread experimentation, which soon engaged the whole local enterprise system’,11
and numerous specialised
construction firms arose and patents led to its ‘incessant diffusion’12
. By the time Nevi was employed ‘it was
4. Frampton, K. 2007. Modern Architecture, 4th edn. (London: Thames & Hudson Ltd.), p. 36.
5. Frampton, 2007, p. 37.
6. Frampton, 2007, p. 37.
7. Billington, D. P. 1983. The Tower and the Bridge: The New Art of Structural Engineering (New Jersey: Princeton University Press), p. 149.
8. Billington, 1983, p. 149.
9. Frampton, K. 2007. Modern Architecture, 4th edn. (London: Thames & Hudson Ltd.), p. 36.
10. Huxtable, 1960, p21.
11. Iori, T. 2006. Engineers in Italian Architecture. The Role of Reinforced Concrete in the First Half of the Twentieth Century, Proceedings of the Second
International Congress on Construction History, pp. 1981-1995.
12. Iori, T. 2006, p.1983.
Fig. 2.1.
2 | Austerity & Experimentation
Fig. 2.1. SACC construction site

16 17
commonly used in construction work’13
.
However, The First World War shortly interrupted his apprenticeship, and Nervi was conscripted to the front
in June 1915. After only two months he contracted Typhoid and after convalescence re-joined the Engineering
Corps in March 1916, where assignment to the new airship battalion reawakened his passion for aeronautics. This
familiarised him with the environment that would later provide an opportunity for his impressive hangars.
Nervi re-joined the Florence branch of the SACC in 1919, as designer and chief engineer, with considerably more
autonomy and responsibility: ‘His many works of concrete, designed, calculated and overseen as supervisor of
works...consolidate[d] his status as a mature, independent professional’14
. He became embedded in the polemics
of local construction industry, joining the local dissemination of engineers in 1921, the Societa degli Ingeneri di
Firenze, The Association of Engineers of Florence, where he was an active member and where his experience
made him a ‘resolute advocate for the recognition of the central role of the engineer in Italian labour policy.’15
Drawing upon his ideals of the engineer at the service of society, Nervi accepted the elected position of president
of the Fascist-affiliated Florentine branch of the Sindacato Nazionale Ingegneri16
in 1923, but refused to comply
submissively and resigned soon thereafter. Following a deterioration of relations owing to ensuing ideological
complications and disagreements over pay, Nervi resigned from the SACC in April 1923, splitting from Muggia and
joined the Roman contractor, entrepreneur and sole financier Rudolf Nebbiosi to form Nervi and Nebbiosi.
The decade with Nebbiosi, from 1923 to 1932 was particularly fruitful, providing Nervi - already in his thirties and
now a partner – with a freedom to ideate and optimise structural and construction techniques affording a chance
for a personal exploration of the potential of reinforced concrete alongside the firms proprietary constructor,
the Società per Construzione Ing. Nervi e Nebbiosi. He created his first original long-span roofs, such as the 1929
Cinema Teatro Augusteo in Naples (fig. 2.2), endowed with some precursory lightness, although the exterior was
still markedly veiled in eclecticism. However his perfunctory structures of the same period - industrial plants,
warehouses, textile and tobacco factories, silos and garages – remained unsmothered.
Nervi’s professional career began against the background of an Italy in a state of political, economic and social
turmoil caused by the repercussions of the Treaty of Versailles at the end of the First World War. Optimism and
internationalisation in 1920’s inter-war Europe yielded to protectionist policies following economic depression
13. Iori, T. 2006, p.1983.
14. Iori, T. 2009. Pier Luigi Nervi, Motta Architettura, Milan, p. 21.
15. Olmo & Chiorino, 2010, p.202.
16. National Syndicate of Engineers.
Fig. 2.2.
Fig. 2.2. The Cinema Teatro in Naples, in
construction. The large, thirty metre free-span
was an important challenge in Nervi’s early
career.

18 19
in the 1930s as ‘democracies as well as dictatorships demonstrated an increased interest in their national
heritage’17
. In Italian social and economic policy this was manifested as autarchy, ‘to achieve a condition of
totalitarian economic independence...to free themselves as much as possible from economic dependence on
foreign countries’18
. While presenting obstacles towards modernisation, through the rejection of foreign goods
and progress, autarchic policies in the 1920s and 1930s favoured the ‘construction of important social buildings’19
and ‘offered opportunities for the development of forms of entrepreneurship and innovation in typological and
constructive techniques’. Constructive and state entrepreneurialism in the 1930s bore new factories, agricultural
warehouses and commercial structures, necessitating new technical solutions for large-span roof structures. As
such in the last decades the Italian cement industry swelled to 37,000 labourers in 2,700 companies, and saw
an eight-fold increase in its compressive performance20
. Like other construction and engineering firms, Nervi e
Bartoli ‘benefitted from the extraordinary programme of modernization of infrastructure and facilities developed
by the Fascist regime. As a driving force of the economy and society as a whole, the construction sector and its
practitioners received numerous public and private commissions’21
However, industrial physiognomy belied its
humble production: ‘Strong innovative instances, either stylistic, technical, or related to production, cohabit with
ways of construction that are still decidedly related to handicraft...favoured by the abundance of available labour
and traditional construction materials...tradition and innovation find a particular balance that is expressed...
that characterise the process of modernisation of the Italian architecture in its typological, technical and stylistic
aspects,’22
reflecting the dualism and also ‘ambiguities of a still not consolidated industrial culture, yearning to
equip itself with the necessary technological infrastructures towards progress.’23
In 1927, as part of a ‘dynamic state policy for sports aimed at the ideal of healthy youth’24
, Moussolini created
CONI – the Comitato Olimpico Nazionale Italiano; Italian Olympic committee. Under its program of new venues
and stadia, Nervi and Nebbiosi, as designer and contractor, presented a competitive bid to build the Municipal
Stadium of Florence. Partially completed by Società per Construzione Ing. Nervi e Nebbiosi, which was dissolved
in 1932, the stadium’s stands and helicoidal staircase were completed by Nervi’s new firm set up in the same
year, the Società per Construzione Ingg. Nervi e Bartolli (fig. 2.3). Founded with Nervi’s cousin, Giovanni Bartolli
- an engineer also employed in Tuscany by Nervi e Nebbiosi - it was an opportunity for Nervi to fully realise his
17. Ben-Ghiat, R. 2000. Fascist modernities: Italy, 1922-1945 (California: University of California Press), p136.
18. Benni, A. 1939. Italian Autarchy in Practice – An Example in the Field of Transportation, Foreign Affairs,17, p549.
19. Barozzi, A. & Guargdigli, L. 2009. Italian Construction in the First Half of the Twentieth Century between Material Restrictions and Innovative
Technology, Proceedings of the Third International Congress on Construction History, p. 2.
20. Barozzi & Guargdigli, 2009, p. 3.
21. Olmo & Chiorino, 2010, p. 204.
24. Olmo & Chiorino, 2010, p.203.
Fig. 2.3
Fig. 2.3. The building yard of Ingg. Nervi e Bartoli

20 21
ideas, which he felt he could only achieve in being responsible for construction25
. He believed it essential that a
project was overseen by one person from conception to completion if quality and costs were to be controlled.
The intersecting, helicoidal staircase (fig. 2.4) and the cantilevered roof and stands (fig. 2.5) were received with
international acclaim and remained a landmark thirty years later26
which demonstrated Nervi’s enlightened
intuition gained from prolonged practice, surmounting the obstacle of limited mathematical computation to
achieve what was graphically inconceivable for his contemporaries. Free from extraneous ornament, it was
perhaps the ‘intricate curves of these staircases which led Nervi to the necessity for eliminating formwork’27
, a
liberation that would exemplify his work, and complementarily achieve the quality of surface finishes he sought,
which had been thus far obtained with expensive, fine cement coatings. As both engineer and contractor, and
given the competitive Italian appalto-concorso tender procedure28
requiring detailed calculations of costs, Nervi
was excellently situated him to make critical economies and became very aware of the most minute incurrences
within the global sum: ‘every steel rod, every bag of cement, every wooden plank, every liter [sic] of petrol used for
transportation,’29
.
Nervi’s parallel roles in design and construction procedures - albeit through conventional technical practice –
exposed him to some of the political affronts that presented both opportunities and defined his adaptability. His
formative professional participation and collaboration contain traces of this which must be seen in context with
these adversities. Often cursorily described, and usually in very summary biographical terms, it does not yet reveal
the structural typologies for which he would become renowned. It is only when he forms his family-run design and
construction firm, Nervi and Bartoli in 1932, that the conditions for methodical experimentation and opportunities
for implementation arise that produce his structural signatures that most dissemination is concerned with.
25. Campbell, B. (ed.). 1955. ‘Pier Luigi Nervi’, Concrete Quarterly, no. 25, (pp. 20-28), p.20.
26. Campbell, B. (ed.). 1957. ‘Italy: The Story of a visit to Northern Italy in October 1956’, Concrete Quarterly, no. 32, January-March (London : Cement
and Concrete Association) ( pp. 8-31), p. 9.
27. Campbell (ed.). 1955, p.21.
28. Mateovics, E. 1996. ‘Nervi’s Mastery of Art in Reinforced concrete (pt. 1)’, Concrete Quarterly, Issue 178, (pp. 2-5), p. 3.
29. Poretti & Iori, T. 2005, p. 607.
Fig. 2.4
Fig. 2.5
Figs. 2.4 & 2.5. Helicoidal staircase and cantilevered
stands of the Florence Municipal Stadium

22 23
2 | Austerity and Experimentation
Economic isolation was crystallised by Italy’s invasion of Ethiopia in 1935 - the Second Italo-Abyssinian War. Italy
already controlled Eritrea and Somalia in Africa but had failed several times to colonise neighbouring Ethiopia.
When Mussolini rose to power he was determined to show the strength of his regime by occupying it30
. The League
of Nations condemned Italy’s aggression and imposed trade sanctions in an attempt to ban countries from selling
products that might aid the war effort - arms, rubber and some metals - to Italy. Whereas concrete was a material
that fascist rhetoric emphasised as a symbol of progress : “There is no static audacity, nor futuristic architectural
line in front of which concrete could stop...concrete is the principal material of the fascist constructions”31
, it
suddenly became anti-autarchic, pressing Italy’s self-sufficiency by requiring both large amounts of precious wood
for formwork and steel for its reinforcement. Despite being the most-commonly used material in the construction
industry it was slowed in 1937 and eventually banned in 1939.
Bound inextricably to the material, the difficulties encouraged Nervi’s invention, and demonstrated his
adaptability, dynamism and resourcefulness. In the military sector projects were reviewed in order to minimize
the use of iron and Nervi was suited to use concrete to be a functional reduction of construction time and cost.
In 1935 he benefitted from the restrictions in winning a competition to build the first of a series of hangars
(fig.2.6) for the Regia Aeronautica, the Italian Royal Airforce, on the basis of his designs’ merit of its economy – it
used steel sparingly - and construction speed as the hangars needed to be replicable identically across different
sites whilst still being resistant to bombardment. One hundred by thirty-five metres across and twenty metres
high, the enormous geodetic ribbed, reinforced-concrete vaults were supported on six inclined buttresses and
covered with asbestos-cement sheets (fig.2.11). The first two, built in Orvieto between 1935 and 1938, were cast
in-situ (fig.2.7). Nervi noted that these required extensive expensive wooden formwork and falsework (fig 2.8.) –
temporary supporting structures - which affected both cost and construction schedule. The technique used in the
subsequent series (fig. 2.9), built between Orvieto, Torre Lago and Torre Del Lago Puccini between 1939 and 1942,
30. Italy in the Second World War, in Spartacus Educational <http://www.spartacus.schoolnet.co.uk/2WWmussolini.htm> [accessed 17 October 2011].
31. Meetings with Reinforced Concrete, Italian Cement Industry, yr. VI, n.12, December 1934, p. n/a.
2.2 Hangars
Figs. 2.6. Interior view, completed hangar in first
series. Formwork board marks are visible on the roof
structure.
Figs. 2.7 & 2.8. Examination of the construction
images reveals the extensive falsework and formwork
required for the in-situ concrete of the first series of
hangars.
Fig. 2.6.
Fig. 2.8.
Fig. 2.7.

24 25
Fig. 2.9
Patent N. 377969:
‘Construction system for the realisation of structural
skeletons for vaults, domes and general static systems
by factory-made [pre-fabricated] elements, and
connected by reinforced concrete elements’
Soc. Ingg. Nervi e Bartoli, Rome, 09 November 1939.
Fig. 2.10. Assembled hangar. some panels have been
in-filled already.
Fig. 2.11. Assembled Structure; completed blockwork
enclosure and asbestos-cement roof
Fig. 2.9.
Fig. 2.11.
Fig. 2.10.
which although almost identical in form avoided the costs incurred by these temporary structures through the
implementation of an elemental and crucial constructive innovation, and the first in a series that would permeate
and revolutionise Nervi’s work thereon: Structural Prefabrication, protected in Patent n. 377969, registered in
Rome in 1939 by Soc. Ingg. Nervi e Bartoli: ‘Construction system for the realisation of structural skeletons for vaults,
domes and general static systems by prefabricated elements, and connected by reinforced concrete elements.’ (Fig.
2.10).
Using this simple notion Nervi decomposed the structure into as few small identical, modular sections as
possible, measuring approximately three-by-one metres. The small, lightweight, prefabricated trusses were made
by pouring concrete into plaster-lined moulds excavated on-site (fig.2.12) – thereby eliminating complex and
expensive wooden formwork - and lifted into place, where it was held in place by significantly simplified falsework
supports (fig. 2.13), and connected by welding their protruding rods and filling the space surrounding the nodes
with strong cement (fig.2.14). The process returned the separate members to static monolithicity much like his
practised Hennebique System. Forming the ribs on the ground also permitted more intricate casting and the
latticed trusses (fig. 2.15.) were considerably lighter, while the repetitive use of identical moulds and shuttering
resulted in significant cost savings32
.
The structures’ scale and complexity were graphically incalculable, and following their design were simulated on
reduced-scale celluloid models (fig, 2.16). Nervi marvelled at the results, which indicated that less reinforcement
was needed than predicted33
. ‘Experimental Model Analysis’34
would become an important tool that Nervi used
to validate his daring structural forms, initially with the help of Dr Arturo Danusso at the Turin Polytechnic and
later at a test facility, the ISMES in Bergamo. It allowed Nervi to overcome the limits of purely graphic calculation:
‘their efficiency in solving complicated statically indeterminate systems (particularly three-dimensional systems)
has not kept pace with either the creative and [sic] structural potentialities...or available construction methods’.35
Not used to explore all his projects individually, these systematic empiricisms were cumulatively informative, and
contributed to the maturity of Nervi’s static intuition. Ironically, these results, determined by experiment and
observed behaviour, allowed a return to convention and were later applied simply graphically as in the case of the
delicate Palazetto. Nervi later became very closely bound to the ISMES experimental test facility, which was set
up in 1951 under the presidency of Dr. Arturo Danusso, and ‘financed by the leading contractors, designers and
32. Mateovics, E. 1996. ‘Nervi’s Mastery of Art in Reinforced concrete (pt. 1)’, Concrete Quarterly, Issue 178, (pp. 2-5), p.4.
33. Blundell-Jones, P. 2002. Modern Architecture Through Case Studies (Oxford: Architectural Press). p. 114.
34. Nervi, P. L. Structures. 1956c (New York: F.W. Dodge Corporation). Trans. by Salvadori, G & Salvadori. 1956. Costruire Correttamente (Milan: Ulrico
Hoepli), p. 87.
35. Nervi, 1956c, p. 87.

26 27
Fig. 2.12. Preparation of prefabricated elements.
Fig. 2.13. Assembly of rpe-fabricated components.
Fig. 2.14. Hangar Joint reinforcement: Protruding reinforcing bars of
intersecting prefabricated elements are tied together in preparation for
welding and pouring over with high-strength concrete.
Fig.2.15. Completed trusses stacked; view of construction site
Fig. 2.16. Experimental model tests.
Fig. 2.12.
Fig. 2.13.
Fig. 2.14. Fig. 2.15.
Fig. 2.16.
cement manufacturers in Italy’36
, and in 1968, following Danusso’s death, Nervi assumed its presidency.
Nervi later conceded that he had observed that the concrete mix used had developed degenerative cracks37
,
which had permitted moisture to seep in and corrode the slim steel reinforcements, and that their demolition by
retreating Germans had saved him by destroying the structures. Peculiarly he had used flour as an anti-corrosive
agent, due to the saline breeze surrounding the coastal structures38
. In order to achieve bolder solutions and
concerned with the quality of finish and performance, Nervi needed materials to be appropriately reliable.
Often undervalued, and evidenced in archived correspondence39
. Nervi extensively discussed with the experts
the appropriate choices of materials and cements, and plastic agents to increase the concrete’s fluidity without
resorting to excessive water amounts, which would cause discoloration and unpredictable curing and strength.
Much of his more daring structural solutions were later possible thanks to his awareness of the behaviour of
concrete, and his insistence on the quality of the mixtures.
36. Campbell, B. (ed.). 1957. ‘Italy: The Story of a vist to Northern Italy in October 1956’, Concrete Quarterly, no. 32, January-March (London : Cement
37. Pier Luigi Nervi, in ISMES (Intituto Sperimentale Modelli e Strutturi) < http://www.ismes.org> [accessed 4 September 2011].
38. Author’s visit to MAXXI Archive, Rome. Conversation with Esmerelda Valente, archivist, 15 September 2011.
39. Nervi keenly wrote to manufacturers and meticulously archived his correspondence, now at the MAXXI Archive in Rome. Author’s visit to MAXXI
Archive, Rome. Conversation with Esmerelda Valente, archivist, 15 September 2011.

28 29
The hangars were Nervi’s final opportunity to construct during the war, as in July 1943 the fascist regime collapsed
and Nazi forces occupied Rome. Nervi closed his firm in order not to collaborate with the occupying forces,
and used this opportunity for reflection and experimentation, considering the lack of materials, particularly of
metals, and retreated to his construction yard, Villa Magliana, near Rome to conduct a rigorous programme of
experiments. For large-scale constructions during in Italy ‘attempts were made to minimise the use of steel... [by]
a more efficient manner for the use of steel and concrete’40
. Operators such as Ricardo Morandi investigated the
potential of prestressing, but Nervi focused on a parallel line of investigation: Ferro-Cement.
Tests on structural elements – beams, slabs and other components conducted by many of the pioneers of concrete
technologies ‘had been widespread in the early decades of the twentieth century and met the need to certify
experimentally the performance of the new technology, at the same time promoting its image and providing
experimental bases for the construction procedures for its theoretical validation.’41
Nervi’s experimental building
yard in Rome was an important environment within which he could ideate and test his ideas (figs. 3.1 - 3.3) Nervi
authored many patents in this way – sometimes submitted in co-authorship with his construction firms – which
evidence his research (see appendix).
Nervi’s 1956 document, Ferro-Cement: Its Characteristics and Potentialities, gives an account of his experiments
during occupation, and ‘the results achieved, and the potentialities’42
, which he proposed calling, owing to its
method of construction, Ferro-Cemento: ‘Ferro-Cement’ (figs.3.7 & 3.8). Its initial application in civil and industrial
fields confirmed the ‘remarkable strength and lightness of this new method of construction, no less its notable
economic advantages and its great adaptability to architectural forms’43
. An invention previously credited to an
40. Poretti, & Iori, 2005, pp. 607-608.
41. Olmo & Chiorino, C. (eds.). 2010, p. 167.
42. Nervi, P. L. 1956a. Ferro-Cement: Its Characteristics and Potentialities (London: Concrete and Cement Association).
Trans. from L’ingenere, No.1, p. 2.
43. Nervi, 1956a, p. 2.
Invention & Implementation
3
3.1 Occupation: Ferro-Cement
Fig. 3.1. Experimental wooden construction for hangars.
Fig. 3.2. Experimental pre-fabricated trusses for second
series of hangars.
Fig. 3.3. Experiemental arch. Trusses visible in
background
Fig. 3.1.
Fig. 3.2.
Fig. 3.3.
Fig. 3.4.
Fig. 3.6.
Fig. 3.5.
Fig. 3.4. Elasticity and flexibility test on a Ferro-Cement
panel at Villa Magliana (notice the corrugated profiles of
the completed experimental warehouse in the background
in background).
Fig. 3.5. Improvised load tests on Ferro-Cement panels
(notice experimental trusses in background).
Fig. 3.6. Workshop load tests in 1943 on panels on Ferr-
Cement ‘plank’ at the Milan Polytechnical University.

30 31
earlier patented process of gardener Joseph Monier for iron-reinforced flowerpots in 1850, ship hulls in 1855, and
graduating to numerous building applications in 186744
- a trajectory much like that of Nervi’s - the composite
material was a significant reinvention central to Nervi’s method and which he described as a ‘Decisive factor both
technically and architecturally.’45
The composition increased the contact surface area and interaction between the cement mix and the
reinforcement – orthodoxically thicker and more sparsely distributed - and created comparable tensile and
compressive behaviour in all directions, overcoming concrete’s anisotropy. The concept of the material was based
on the observation that ‘the elasticity of a reinforced concrete member increases in proportion to the subdivision
and distribution of the reinforcement throughout the mass’46
. This entailed a layered stack of small diameter wire
mesh from 0.5 to 1.5 millimetres in diametre, with a one centimetre-squared grid of the kind typically used in
ceiling construction or concrete products. Greater thickness and strength could be achieved by introducing larger
bars of six to ten millimetres between the layers of mesh, and ‘without significant loss of the performance of the
material’47
. This was then covered with a fine mortar, which was worked through evenly to the other side and
smoothed. The thickness of the finished slab was little greater than the assembled layers of mesh, the difference
being only as much as to provide ‘adequate cover for the steel’48
. Nervi marvelled: ‘Its most important qualities,
and those which are of the greatest importance in construction, are the great elasticity and resistance to cracking
given to the cement mortar by the extreme subdivision and distribution of the reinforcement, and the fact that the
mortar itself can be applied without the need for formwork, and remains held perfectly in place by the mesh.’49
.
Ferro-Cement achieved Nervi’s sought-after constructive goal, of removing concrete from casting in cumbersome
and costly formwork and the reduction of reinforcement: ‘no formwork whatever was required – a constructional
characteristic of which I would like to emphasize the fundamental importance’50
, and he alluded to the sculptural
quality of its production: ‘The cement mortar which, applied from the inside, comes through to the exterior where
it is worked and smoothed with a plasterer’s technique.’51
Unlike typical reinforced concrete, it had the ‘mechanical properties of a completely homogenous material.’52
Tests
carried out in the Summer of 1943 under the supervision of the Italian Naval register, first at Nervi e Bartoli’s
construction yard, Villa Magliana (fig. 3.4 & 3.5 ), and then Models and Constructions Testing Laboratory at the
44. Frampton, K. 2007. Modern Architecture, 4th edn. (London, Thames & Hudson Ltd.), p. 37.
45. Nervi, 1956c, p.56.
46. Nervi, 1956a, p. 2.
47. Nervi, 1956a, p. 1.
48. Nervi, 1956a, p. 2.
49. 34
Nervi, 1956a, p. 2.
50. Nervi, 1956a, p. 5.
51. Nervi, 1956a, p. 5.
52. Nervi, 1956a, p. 2.
Fig 3.7.
Patent N. 406296:
Improvements on the construction of slabs, surfaces and other
reinfored-concrete structures.
Pier Luigi Nervi, Rome, 12 Januray 1942
(Ferro-Cement Patent)
Fig. 3.8. Ferro-Cement sample
Fig. 3.7.
3 | Invention & Implementation
Fig. 3.8

32 33
University of Construction Science of the Reale Politecnico di Milano, in Milan(fig. 3.6.), confirmed the shock-
resistance and extensibility of Ferro-Cement. Shortly afterwards Nervi began construction of a 400-tonne motor
vessel, and three 150-tonne vessels for the Italian Navy. However, the military events of 1943 shortly prevented
continuance of work.
After conflict subsided, in the summer of 1945 Nervi e Bartoli built for their own use the 165-tonne motor-yacht
‘Irene’ (figs. 3.9 – 3.11). This demonstrated ‘the simplicity of the method and, on launching the vessel, its perfect
agreement with expectations’53
. The success of the technique was an illustration of the poverty of means that
Nervi faced and his resourcefulness, an attitude that necessarily pervaded the industry: ‘At the time there was
no mechanical equipment left in the yard, and no electricity...No traditional method of construction would have
enabled a ship to be built in such conditions and in the short time.’54
It was an artisanal technique that relied on
Nervi’s engineering ability during the design and planning stages but could ‘easily be implemented on a traditional
building site’55
as it did not require specialised labour or additional mechanical plant.
Its first application in building construction in 1946 was a twenty-one by twelve metre experimental warehouse,
built by Nervi and Bartolli at Villa Magliana (fig. 3.12 & 3.13). Freed from the restrictions imposed by straight
planks for casting formwork and in order to make the thin, thirty millimetre wall profiles resist deflection, Nervi
designed corrugated wall profiles. These undulating profiles (fig. 3.14) demonstrated his static intuition, and his
capacity for structural invention, which was afforded by the system, and revealed a formal strengthening model
that would reoccur many times thereafter. Steel meshes, previously-shaped on a wooden mould (fig.3.15), were
placed against vertical wooden posts (fig. 3.17), and ‘covered by hand with a fine cement mortar of good quality
(figs. 3.16 & 3.18); the mortar pressed on one side, filled up the spaces of the steel frame penetrating to the other
side only so much as to require a simple shaving to obtain the wanted thickness of 30mm, and a good finish’56
. The
structure still stands today, and over 50 years later tests have shown the ‘excellent condition of the mortar and an
almost complete absence of cracks.’57
Owing to the interaction with the work-surface, the quality of Ferro-Cement construction was very reliant on
the quality of workmanship and brought a distinctly artisanal quality. Nervi trusted and valued his workforce.
Nervi’s firm was not always responsible for construction, and if work was destined for another builder in a
53. Nervi, 1956a, p. 5.
54. Nervi, 1956a, p. 5.
55. Poretti & Iori, 2005, p.608.
56. Greco, C. 1995. The “Ferro-Cemento” of Pier Luigi Nervi – The New Material and the First Experimental Building’, Proceedings of the IASS
International symposium, p. 315.
57. Greco, 1995, p. 315.
Fig. 2.23
Fig. 3.10.
Fig. 3.11.
Fig. 3.9.
Fig. 3.9. Scaffolding
around construction of the
reinforcement mesh for the
ship hull.
Fig. 3.10. Applying
mement mortar through
the reinforcement mesh.
Fig. 3.11. The 165 tonne
motorboat ‘Irene’.

34 35
bidding competition, he was prudent and conservative. If instead he was responsible for the implementation of
the project as well, then he used the opportunity to develop new ideas58
. Nervi championed construction, and the
workers, and viewed them as sculptors rather than builders. Their abundance did not affect their compliance;
speed and efficacy, a general culture of constructive pride pervaded were crucial agents: ‘There is of course no
labour shortage in Italy...the superabundance of operatives seems to have had the adverse effect on their attitude
to work. Italian builders remain self-respecting craftsmen; they work quickly and well. The same self-respect, and
respect for the job, appears to run right through the heirarchy of construction.’59
He meticulously documented his
construction sites, and was often to be found there, and frequently made design and construction alterations based
on - and whilst on - these excursions60
. Nervi’s adoration of the artisan appeared to surpass the professional, and
achieve the personal:
“From the point of view of the construction the choice of good worker/carpenter has been sufficient, you see, the
thing you appreciate more during a life such as mine is being in contact with the workers...It is difficult to imagine
how they understand, how they help, and how they come up with ideas, and we can explain the success of ancient
buildings thanks to the workers that knew what they were doing...I, during the time I used to work in construction,
had the possibility to gather around fifteen men, my assistants, team leaders, that built with their bare hands the
most delicate things. Trust me when I say that it is extraordinary receiving the help that can be obtained when you
are acquainted, or even friends with good workers...Having good workers is really one of the most important things
to achieve construction refinement; this cannot be defined by line drawings on paper, there always needs to be the
intervention of the work and the good will of the worker...It is not true that there is such a distance between the
engineer and the workers. You can sometimes eliminate this distance at an advantage for both...and it is an advantage
for the engineer and the architect that finds such valid collaborators...”61
Nervi’s exposure to and innovations in construction had now produced two significant innovations: Ferro-Cement
and his earlier elucidation of Structural Prefabrication, to form the economical construction process which came
to be known as the Nervi system. In popular critical evaluation the significance of the sequence of this causation
seems understated. His experiments with Ferro-Cement and particularly their transition to architectural
constructions, in the experimental warehouse, fundamentally changed the way in which he would ideate concrete
structure: “a true revolution from…the construction point of view”62
. Ferro-Cement profiles were relatively light,
58. Pier Luigi Nervi, in ISMES (Intituto Sperimentale Modelli e Strutturi) < http://www.ismes.org> [accessed 4 September 2011].
59. Italy: The Story of a vist to Northern Italy in October 1956, Concrete Quarterly, Issue 32, January-March, 1957, Cement and Concrete Association,
London, p. 8.
61. Transcript Excerpt, Propos sur la philosophie des structures, École Polytechnique Fédérale de Lausanne. Provided by Irene Nervi on 26 September
2011, Translation by author.
62. Greco, 1995, p.311.
Fig. 3.13.
Fig.3.14
Patent N. 429331; Second Revision of P. 406296:
Improvements on the construction of slabs, surfaces and other
reinforced-concrete structures.
Pier Luigi Nervi, Rome, 29 September 1944.
Fig. 3.12.
Figs. Fig. 3.12. & 3.13. Exterior of the Experimental
warehouse; elevation and Plan.
Fig. 3.14.

36 37
and supported the economical realisation of curved concrete profiles, and allowed Nervi to employ geometry to
achieve strength. This eliminated the requirement for separate, supporting structures. Two distinctive precast
structural configurations would emerge from the Ferro-Cement technology, based on decomposition principles for
the prefabrication of large surfaces: the Strutture Undulate – Undulating Surfaces – and the Tavellone – rhomboidal
tiles. Ferro-Cement crucially became structure; its suitability for long-span enclosures was proved with several
high-profile public projects that became emblematic of the recovery of post-war Italy.
Fig. 3.17. Fig. 3.18.
Fig. 3.16.
Fig. 3.15.
Fig. 3.15. Reinforcemnt bars and mesh
repeatedly formed around wooden forms.
Fig. 3.17. Meshes set in place; site inspection.
Figs. 3.16 & 3.18 Cement mixture smoothed
over the reinforcement.

38 39
The Italian Economic Miracle, a period of sustained economic growth from 1945 to 1964 transformed Italy from
a poor, mainly rural nation into a major industrial power. This phenomenon was catalysed by a series of global
political events; initially stimulated by generous financial aid from the USA under the Marshall Plan and the
successive 1950 to 1953 Korean War’s demand for metal and other manufactured products63
, and finally the
creation in 1957 of the European Common Market, providing foreign investment and eased exports. Together
these heralded a period of ‘exceptional artistic and cultural production’64
. These favourable conditions, when
combined with a large and cheap stock of labour, created ‘a period of exceptional development in the sector of
large structures’65
, and a ‘Golden Age’ of engineering. Italy was a newly unified country that over the last century
had suffered from the successive setbacks of two global conflicts, trade sanctions and turbulent regime changes
and as such experienced consequent setbacks to industrialisation. However there existed a “paradox by which
structural engineering ended up in such an advanced stage of experimentation [Both in production volume, and in
exemplary expressions] precisely in a country suffering from a serious delay in technological progress’66
. Further,
the anachronistic labour-centric executions were ubiquitous but evidently no impedance to construction as ‘even
the most diverse works shared a common trait: the contrast between the advanced stage of structural theory
applied in calculation and the artisanal character of the reinforced-concrete worksite; a character that did not
substantially change as the techniques evolved’67
.
Reconstruction, while initially slow in the residential sector, was fertile in the field of infrastructure, in rebuilding
of some 2,600 bridges destroyed during the war68
and in the context of plans for new international airports and
highways: ‘this was the moment to test the lines of experimentation that had been developing for many years.’69
63. Crafts, N. & Toniolo, G. 1996. Economic growth in Europe since 1945 (Cambridge: Cambridge University Press), p. 141.
64. Forgacs, D. & Gundle, S. 2007. Mass culture and Italian society from fascism to the Cold War (Bloomington: Indiana University Press), p. 27
65. Iori, T. & Poretti, S. 2009,The Golden Age of “Italian Style” Engineering,
Proceedings of the Third International Congress on Construction History, p. 1.
66. Iori & Poretti. 2009, p. 1.
67. Iori & Poretti. 2009, p. 5.
68. Iori & Poretti. 2009, p. 1.
69. Iori & Poretti. 2009, p. 1.
3.2 Reconstruction Opportunities

40 41
Dominated by a line of autocratic experimentation parallel to that of Nervi’s (though not exclusively, and somewhat
to his frustration), prestressed bridges were widely implemented ‘in close continuity with the theoretical works
of the 1930’s’70
, by such engineers as Morandi and Musmeci. Foremost an engineering concern, the contemporary
cathedrals - warehouses, expositions and factories and stadia - represented the frontiers of design; their
unprecedented scale required challenging solutions for the enclosure of space, and those qualified such as Nervi
and contemporary structural architects – Ricardo Morandi, Sergio Muscemi, and Silvano Zorzi – in the 1950’s
benefitted from ‘opportunities provided by a programme of public works financed during the presidency of
Giovanni Gronchi’71
. Rational and perfunctory ideation transcended engineering and became a building lexicon
that was a widespread current of structural expressionism in Italy, and which even infiltrated the ‘linguistic matrix
of realism that characterised Italian architecture as a whole in those years’72
.
Nervi’s process endowed his structures an unprecedented lightness, and comparisons are keenly drawn to the
international phenomenon of ‘Thin-Shell’ architectures, actors whose credentials were comparable to Nervi’s
and also ‘acted as structural engineers, architects and builders. They had similar education, entrepreneurial
characters, and goals...were all well-educated in structures, and part of their education was critically studying built
structures, including their own works...their goal was to design thin shells that would be disciplined by efficiency
and economy’73
. Peculiarly, given its complexity, and lack of technical precedent, contemporaneous thin-shell
construction was largely dominated by these small, pioneering, construction-led practises - such as Felix
Candela, Heinz Isler and Anton Tedesko - and owing to their constructional empiricism and intuition required
to conquer the new material and graphically incalculable forms. Architectural excitement mostly surrounds
the more expressive, ‘formless’ plasticity explored by thin-shell designers in the 1960’s. However, these were
largely novel forms, used in shorter-spanning and less-frequent applications. Nervi’s structures crucially
differed in that his relative interest lay in the industrial and public scale with the monumentality that he was
able to economically achieve with his proprietary techniques. Adamantly not driven by formal paradigmatic,
sculptural smooth shells, his corrugated and cellular ribs disrupted thin-shell planarity, but created the
necessary stiffness over longer spans. Shell-builders sought to eliminate any traces of construction and
structural composition - rather drawing attention to their geometries – but for Nervi prefabrication evolved
perfectly towards structural expression. He did not have the luxuries of sculptural experimentation, and
necessarily designed systems and procedures that made his projects both cheap and rapid to construct. It was
these attributes that would crucially allow him to win competitive bids. Also demonstrating a fascination with
70. Iori & Poretti. 2009, p. 1.
71. Poretti & Iori, 2005, p. 609.
72. Iori & Poretti. 2009, p. 5.
73. Nordenson, G. 2008. Seven structural Engineers; The Felix Candela Lectures (New York : The Museum of Modern Art, New York), p. 161.
Figs. 3.19 & 3.20. Milan Fair in 1946: Laying out moulds on roof model;
internal view of completed celing.
Figs. 3.21 - 3.24. Construction of thePool for the Naval Academy in
Livorno in 1947: cement-coated masonry mould with completed sections in
background; laying reinforcement into the mould, to be smoothed-over with
cement; lifitng a section into place; comnpleted interior.
Fig. 3.19.
Fig. 3.20
Fig. 3.21. Fig. 3.22. Fig. 3.23.
Fig. 3.24.

42 43
production, but failing to make economising innovations; in Switzerland Isler achieved expensive curvatures
by smoothing mixtures over meshes laid in-place, and in Mexico, Candela used ruled-surface formworks
to achieve parabolic surfaces. However, they slow to construct and only moderately economical, and were
restricted to limited experimental instances with ambitious clients; their ‘aesthetic appeal and intellectual
excitement....were not competitive with other structures’.74
Also in North America, where labour was relatively
unaffordable, Anton Tedesko made meagre advances owing to firms’ unwillingness to invest in research into
new systems.
Nervi had several opportunities to test the possibilities of his new system after the war, and did not hesitate to do
so ‘without significant variation’75
in the construction of a series of domes, vaults and ceilings in the next few years
was. After the confirmation provided by the experimental warehouse in Magliana in 1945, and uninterrupted
experimentation since 1939, he applied it to prefabricated enclosures for the Milan Fair in 1946 (figs. 3.19 & 3.20),
an agricultural warehouse in Torre in Pietra in 1947, the Conte Trossi shipyard in 1947, the swimming pool of the
Naval Academy in Livorno in 1947 (figs. 3.21 – 3.24), the restaurant of the Kursaal Hotel in 1950 (Figs. 3.26 – 3.28)
and the function room of the Thermal Baths at Chianciano in 1952 (Fig. 3.25).
74. Fischer, R. E. (ed.). 1964. Architectural Engineering - New Structures (Maidenhead: McGraw-Hill, Inc.), p.26.
75. Nervi, 1956c, p. 75.
Fig. 3.26
Fig. 3.25. Interior view of the ceiling of theFunction room of the
Baths in Chianchiano in 1952.
Figs. 3.26. - 3.28. Restaurant of the Kursaal Hotel in 1950; exterior
views of construction; partially-completed roof.
Fig. 3.27.
Fig. 3.28
Fig. 3.25.

44 45
However the first and perhaps most challenging opportunity for their simultaneous implementation was in the
autumn of 1947, on Hall B of the Turin Exhibition, the ‘Salone Agnelli’. The director of the Exhibition held a design
competition for a large rectangular hall one hundred by eighty metres and with a semi-circular apse sixty metres
in diameter, to replace the one damaged in the war. Nervi won the commission on the merits of brevity of time
allowed for construction and cost requirements using his yet publicly unimplemented pre-cast solutions of the
composite Nervi System. Ferro-Cement allowed Nervi to ‘limit the weight of the elements, which must not surpass
the lifting ability of normal equipment (figs. 3.35 – 3.36), and make it possible for them to be easily and rapidly
erected and joined…[as]objective solutions using prefabricated parts.’76
For the main vaulted enclosure he used
semi-wave sections of two to three metres – validated in his 1945 experiment and consolidated in an additional
1948 patent for undulating structures – Strutture Cementizie Ondulate (fig. 3.29.) - attaining the ‘necessary stability
by virtue of the corrugations.’77
Reinforcing mesh was formed on wooden forms (fig. 3.30), and then placed in
plaster-lined moulding forms with longitudinal steel bars. Concrete was then poured on and smoothed over to
a finished thickness of three centimetres. The pieces were raised and held into place by temporary supports, on
movable scaffolding with a built-in lifting device (fig. 3.35 – 3.36). Nervi favourably commented on the efficiency
of process: ‘the casting of the moulds proceeded without any difficulty and without the need for double formwork,
as would have been the case with ordinary reinforced concrete….Lifting and placing the units proceeded regularly
(the units were unmoulded in two or three days) and enabled about 3,200 square-foot of roof to be completed
each day.’78
Concrete ribs were cast along the peaks and troughs - along the radial direction - to create transversal
connections between the single pieces, rendering them monolithic: ‘static collaboration between the elements...
assured by the reinforcing rods...protruding from the element’79
(Figs. 3.37 & 3.38). Stiffening during handling
and moving into place was provided by perpendicular diaphragms pre-cast at the ends of each section. The
76. Nervi, P. L., Trans. by Einaudi, R. 1966. Aesthetics and Technology in Building, The Charles Eliot Norton Lectures (1961–1962), (Cambridge, MA:
Harvard University Press), p. 100.
77. Huxtable, A. L. 1960. Pier Luigi Nervi (New York: George Brazilier, Inc.). p.26.
78. Huxtable, 1960, p.26.
79. Nervi, 1966, p.121.
3.3 Turin Exposition
Fig. 3.29. Section through a precast element of the roof of the Salone Agnelli, the Main Hall of the
Turin Exposition, 1947, protected by Nervi’s 1948 patent:
Patent N. 445781
Construction methods for the realization of wavy or curved concrete structures -
‘Strutture Cementizie Ondulate’ - with or without pre-tensioning.
Pier Luig Nervi, Rome, 26 November1948.
Fig. 3.29.

46 47
Figs.3.35 & 3.36. The movable scaffolding with built-in
lifting device for moving and positioning the pre-cast
elements
Figs. 3.33 & 3.34 Completed precast elements on site.
Fig. 3.34.
Fig. 3.33.
Fig. 3.36.
Fig. 3.35.
Fig. 3.30.
Fig. 3.32.
Fig. 3.31.
Fig. 3.30. Forming the reinforcement over wooden forms.
Figs. 3.31 & 3.32. Precasting in the basement.

48 49
lengths gathered through fan-shaped elements at their bases that collected the forces and directed them through
inwards-inclined buttresses, which were completed in-situ during groundworks procedures. Importantly
the monumentality of the project provided the necessary arrangements and spatial freedom to carry out his
procedures of on-site prefabrication. Remarkably, during the construction of the Salone Agnelli, Nervi even
planned and carried-out extensive pre-casting in the basement after the completion of the groundworks and
ground floor of the project, allowing the schedule to proceed uninterrupted, despite the inclement winter (figs.
3.31 & 3.32).
For the Semi-circular end apse spanning the width of Salone B, Nervi introduced a new kind of prefabrication, a
surface decomposition in the shape of rhomboidal ‘tiles’ – Tavellone. (fig. 3.46 – 3.48): ‘I used a method…which I
had studied and actually used, though on small-scale structures, immediately after the war…inspired by the need
for economising in timber, which was [still] extremely scarce in Italy at the time…the units are cast in concrete
moulds, which in turn are constructed on a model reproducing a section of the vault or dome to be built (as in
fig. 3.19). The edges of each unit are so shaped that when placed side by side, they form a network of supporting
ribs that complete the structural system.’ Nervi protected his procedure in May 1950, under his patent N. 465636,
Procedures for the realization of flat or curved resistant surfaces consisting of Ferro-Cement concrete ribbed-
networks with or without connection plates between the ribs. (fig. 3.49).
In 1949 the directors of the Turin Exhibition decided to enlarge the exhibition complex by adding a rectangular
hall, Salone C (fig. 3.50 – 3.53.), measuring sixty-five by seventy metres. The design and construction was again
to Nervi’s firm on a competitive cost basis as ‘the technical problem was conditioned by time constraints,’80
and
provided an opportunity to perfect the same rhomboidal Tavellone typology (figs 3.46 – 3.48), as previously
validated on the apse. Again Pre-casting was carried-out in the basement of the now-adjoining hall (figs. 3.41 –
3.45). Nervi’s increasing adoration of his bespoke manual procedures is clear, even in the Ferro-Cement moulds
made for the in-situ beams: ‘The visible underside of the form, which is in contact with the mould during casting,
is regular and smooth, with a perfection of surface that could never be obtained by any of the usual finishing
processes. This method of construction is very adaptable; I have used it many times for curved structures, and
always with excellent results.’81
The economies of self-construction were satisfied in Nervi’s prefabrications, which were confirmed as a ‘logical
80. Nervi, 1966, p. 103.
81. Huxtable, 1960, p.27.
Fig. 3.37. Fig. 3.38.
Fig. 3.37. - 3.40. Pre-fabricated
ceiling units of the Salone Agnelli
in place; protruding reinforcement
visible joined by in-situ pours
along their summit and base;
juncture with the fan-shaped
details leading to the in-situ
butresses.
Fig. 3.39.
Fig. 3.40.

50 51
fig. 3.48.
Section of the precast elements
fot the dome.
Nervature Disposte Tra Tavel-
loni
Ribs arranged between the tiles.
Tavelloni Prefabricati
Pre-fabricated ‘Tiles’
Nervatura in cemento armato
gettato in opera
Reinforced-concrete rib cast
in situ
Solettina di completamento get-
tata in opera
Completion slab cast in-place
Figs. 3.46 & 3.47
Salone Agnelli: the half-dome
during construction. When in
positionthe precast elements
form grooves into which steel
reinforcement is placed and
concrete poured to statically
combine the elements.
Axonometric Drawing of precast
Tavellone element.
Fig. x
Figs. 3.41 - 3.45
Salone C: preparation of the precast Tavellone members for the
vault. Precasting procedures in the basement.
‘Note the simplicity, and therefore the intrinsic economy, of the
equipment required’
Nervi, 1966, p.130.
Fig. 3.44. Fig. 3.45
Fig. 3.41. Fig. 3.42. Fig. 3.43.
Fig. 3.46.
Fig. 3.48.
Fig. 3.47.

52 53
Fig. 3.50.
Fig. 3.52.
Fig. 3.51.
Fig. 3.53.
Fig. 3.49.
Patent N. 465636
Procedures for the realization of flat or curved resistant surfaces consisting of Ferro-Cement
concrete ribbed-networks with or without connection plates between the ribs.
Pier Luigi Nervi, Rome, 19 May 1950.
Fig. 3.50 ‘Note the relative simplicity of the
temporary formwork for the placement of the
elements compared to that of the cast-in-place
vault’.
Nervi, 1966, p.130.
Fig. 3.51. Roof construction of Salone C.
Fig. 3.52. Construction of the vaulted roof of
Salone C. The precast elements are in the first
two rows are formed by only the ribs, which
will remain open to allow light in. The steel
reinforcement has already been placed in the
lower ribs. Note the upper part of the photograph
the reinforcing steel protruding from the precast
elements to insure a static tie with the thin slab
that willl be cast in place over them.
fig. 3.53. Interior view of completed Salone C.

54 55
economical progression of the building activity and…provisional work,’82
benefitting from moderate incidence
of transportation – owing to on-site storage and prefabrication - and simultaneous working of different parts of
construction: ‘operational progression of the building activity is quicker because several elements can be done
contemporaneously…whilst foundations are prepared the prefabricated elements can be cast,’83
and in the speed of
the final assembly.
Indicative of the didactic structures and innovative construction, the Salone Agnelli (fig. 3.54) was published for
the first time even before its completion, in the Turin publication Atte e rassegna Tecnicadella Societa degli Ingeneri
e Architetti di Torino,84
and keenly disseminated in foreign publications in the years thereafter85
(fig. 3.56). On 15
September 1948, only six months after the first excavation,86
when the inaugural international Turin Motor Show
opened (fig. 3.55), journalists and critics showed more interest in the architecture than the exhibits themselves,
and the building itself was presented the following month in an exhibition for Technology87
.
82. Tampone G & Ruggieri N, Structural Invention and Production Process in the [sic] pier luigi’s Work, Proceedings of the First International Congress on
Construction History, Madrid, 20th-24th January 2003, ed. S. Huerta, Madrid: I. Juan de Herrera, SEdHC, ETSAM, A. E. Benvenuto, COAM, F. Dragados,
2003, p. 1928.
83. Ruggieri & Tampone, 2003, p. 1927.
84. Technical Review of the Society of Engineers and Architects of Turin
85. Greco, C. 2008. Pier Luigi Nervi: Dai Primi brevetti al Palazzo delle Esposizioni di Torino 1917-1948 (Lucerne: Quart Verlag). P. 245.
86. Campbell, B. (ed.). 1957. ‘Italy: The Story of a vist to Northern Italy in October 1956’, Concrete Quarterly, no. 32, January-March (London : Cement
87. Greco, 2008, P. 245.
Fig. 3.54. View of the Salone Agnelli. Overhead
richness of forms given by the Strutture Undulate..
The cricular apse, using with the alternative
technology - Tavellone, is visible at the end.
Fig. 3.55. Titlepage of La Technique des Travaux,
September-October 1949.
Fig. 3.56. Inaugural international Turin Motor
Show, September 1948.
Fig. 3.54.
Fig. 3.56.
Fig. 3.55.

58 59
Whereas Turin had provided Nervi an opportunity to test his technology on a mature scale, the structures
simultaneously built for the Olympics provided the ‘opportunity for the definitive fine-tuning of the Nervi
System’88
, demonstrated through simultaneous experiments. Under the auspices of the Italian Olympic Committee,
CONI – the same client as for his earlier stadium in Florence - Nervi designed functional and iconic sports venues
for the 1960 Summer Olympics in Rome. He produced four reinforced concrete structures: two prefabricated,
free-spanning, domed arenas employing separate decomposition principles suited to Nervi’s system, made
particularly economic by their symmetrical surfaces of revolution: the Palazzetto dello Sport – Small Sports Palace,
with architect Annibale Vitelozzi from 1956 to 1957, and the Palazzo dello Sport – Sports Palace, with Marcello
Piacentini from 1958 to 1959. Two other structures less indicative of the artisan or expressive of prefabrication:
the Stadio Flaminio (fig. 4.2) from 1956 to1959, Corso Francia viaduct (fig. 4.4) from 1958 to 1960 are of less
interest, given the current discussion, and technically and constructively less identifiable, although they are worth
a brief mention to demonstrate Nervi’s typical constructive resourcefulness and mindfulness, particularly the
firm’s maturity as the almost family-run Impressa Ingg Nervi and Bartoli was the sole contractor for the entire
Scheme (fig. 4.3).
The Stadio Flaminio, completed in 1959, replaced the 1911 Nazionale Stadium, which was demolished for its
inadequate capacity. It necessarily reoccupied the same area, accommodating a superior fifty-thousand spectators,
and with auxiliary athletic functions such as practise pools, gymnasia and cloakrooms accommodated around its
lower perimeter. For the design Nervi collaborated with his son Antonio, and the Impressa Ingg. Nervi and Bartoli
was contractor for the whole scheme,89
which was awarded to the firm as a result of an invited design-and-tender
competition.90
A distinctive canopy cantilevering fifteen metres forwards over the stands and twelve metres back
(fig. 4.8.), poised on the tops of some of the ninety-two equally-spaced portals (fig.4.7.) that support the main
88. Iori, p. 68.
89. Cresciani, M. 2010, Olympic Legacies, Concrete Quarterly, Issue 231, ( pp.12-13), p. 12.
90. Nervi, 1956c, p.84.
4
PALAZZETTO
4.1 Works For the Rome Olympics
Fig. 4.1. Aerial view of the Corsica Francia viaduct; in the
the left foreground is the Flaminio Stadium, and above it the
Palazetto Dello Sport. The Olympic Village is bisected by the
elevated road.
Fig. 4.2 Stadio Flaminio
Fig. 4.3 V-shaped floor units in the foreground; the Palazzetto
Dello Sport in the distance.
Fig. 4.4 Corso Francia viaduct
Fig. 4.1.
Fig. 4.2.
Fig. 4.4.
Fig. 4.3.

60 61
stands and cantilevered gallery access. Owing to complications that the playing area and public access had to be
left unimpeded during the works, a central mixing plant and casting yard was set up at the Southern end of the
stadium, discharging mixes up to two hundred metres along piping to in-situ pour sites91
, and where precasting
of some of the elements was carried-out while the portals and other in-situ work was being constructed (fig. 4.5.)
‘so that no time was lost.’92
The finish of the in-situ works was described as ‘superb… largely on the fine quality
of the natural concrete…left everywhere visible…cast against timber formwork… left as they came out of their
forms’93
. The precast Ferro-Cement structural seating (fig. 4.6.) also achieved ‘a perfectly smooth finish, requiring
no subsequent treatment’94
.
The Corso Francia viaduct ran alongside the Stadio Flaminio and Palazzetto Dello Sport, bisecting the Olympic
Village athletes’ accommodation (fig.4.1) Sixteen metre-long precast, pre-compressed columns provided the
structural spans for the road surface, and rested on cast-in-place, variable-section columns (figs. 4.10 – 4.12)
- another of Nervi’s structural trademarks. The columns were all cast using four reusable forms, which were
progressively shortened from the bottom for shorter columns95
(fig.4.9). The columns’ variable sections were
‘determined by static and construction considerations’96
making a hyperbolic transition from cross-shaped base
sections to rectangular tops. The V-shaped beams – technology adjusted from the Palazzo - were precast and
prestressed, on brick moulds covered with a fine cement coating (fig.4.13). Although employing a similar mould
creation process, Ferro-Cement profiles alone could not provide the necessary thickness for the required bearing
capacity and after the positioning of the reinforcement a wooden counter-mould was placed over the brick mould,
and concrete simply poured in.
91. Campbell, 1959, p. 40.
92. Campbell, 1959, p. 40.
93. Campbell, 1959, p. 40.
94. Nervi, 1956c, p.84.
95. Nervi, 1966, p. 176.
96. Nervi, 1966, p. 176.
Fig. 4.6. Corso Franco Viaduct, 1960
Figs. 4.7 - 4.9 Placement of the
v-shaped elements
Fig. 4.10. Masonry moulds; cured
beam removed from the form; other
member drying in foreground;
proximity of casting procedure to
Corso Franco viaduct (far-right)
illustrates immediacy of on-site
casting procedures.
Top-to-bttom: Figs. 4.5. - 4.8.
Fig. 4.13.
Fig. 4.9.
Top-to-bttom: Figs. 4.10. - 4.12.
Fig. 4.5 Lifting Pre-cast canopy
elemnents into place.
Fig. 4.6 Partially-completed
portals and Ferro-Cement
structural seating units.
Figs. 4.7 & 4.8. Views of
cantilevered roof and stands.
4 | Palazzetto

62 63
Nervi’s firm was again sole structural contractor for the Palazzo dello Sport (fig. 4.19) and the structure was
completed in just thirteen-and-a-half months, from. The dome itself was assembled in only two-and-a-half months
(figs. 4.25 – 4.29). It was declared at the time as ‘ perhaps Nervi’s greatest building to date’97
. A one-hundred-and-
twenty metre diameter dome - the largest reinforced concrete dome of its day98
- encircled by tapered, peripheral
columns, it was designed to accommodate larger-capacity sporting events, such as tennis, basketball and boxing,
with greater capacity than the Palazzetto: up to sixteen-thousand.
It bears a strong compositional and obvious typological resemblance to the earlier 1955 Palazzetto dello Sport,
but was importantly favoured by a different prefabrication procedure (which we will explore below): a scaled
and slightly and modified iteration of the technology tested the Salone Agnelli’s channels of perforated Strutture
Undulate. This involved four to five metre-long, pre-cast, Ferro-Cement channels (figs. 4.20 & 4.21), reinforced
with cast-in-place concrete ribs in the ridges and valleys. Although it differs in its radial, rather than parallel
arrangement and varying depths - from half a metre at the crown - to just over a metre at the lower edges. As in
Turin, the thrust of the dome is taken by the statically indicative fan-shaped supports, which ‘gather the thrust of
the corrugations of the dome and concentrate them on the top of the inclined columns of the gallery below’99
.
The structure is dismissible for failing to satisfy Nervi’s essential architectural criteria: ‘It must give a convincing
answer to a real and authentic static necessity and be determined by it; a static scheme should become visible
and comprehensible inside and outside; it must express frankly the material with which the structure is executed
and find in the technological characteristics of the material itself the sources and ways, as well as the details
of its architecture’100
. Although partially submerged to reduce its height, only the lowest seating tier could be
accommodated below ground level, and the wider, higher dome does not satisfy the same static logic and visual
97. Campbell, B. (ed.). 1959. ‘Nervi’s Contribution to the New Rome: buildings for the 1960 Olympics’, Concrete Quarterly, Issue 42, (pp. 35-43), p. 40.
98. Cresciani, 2010, p. 12.
99. Nervi, 1966, p. 159.
100. Nervi, P. L., 1963b, ‘Some Considerations About Structural Architecture’, Student Publications of the School of Design 11/2, p.43.
4.2 Palazzo Dello Sport
Fig. 4.14.
Fig. 4.15.
Fig. 4.16.
Fig. 4.17. Fig. 4.18.
Fig. 4.14 - 4.16. Images revealing the visually unsatisfactory
transition of forces through the fanned support, through the
gallery floor and to the ground below.
Fig. 4.18. Glazed gallery surrounding the Palazzo
Fig. 4.19. View of the Palazzetto, rising on a hill,
dominates the central Olympic site.
4 | Palazzetto

64 65
Fig. 4.19.
Fig. 4.20. Fig. 4.21.
Fig. 4.25.
Fig. 4.24.
Fig. 4.23.
Fig.s 4.22. - 2.25 Erection and arrangement of of the precast,
v-shaped roof elements
Figs. 4.24. - 2.29 Cast-in-place, inclined columns; fan-shaped sup-
ports; view of the enormous, unfinished interior; view form inside the
unfinished Palazzo. A central crane lifts the pieces into place.
Top-to-bottom: Figs. 4.26. - 4.29
Fig. 4.19. Axonometric drawing and elevation
of v-shaped element, showing adjacent
arrangement and purtruding reinforcement
rods.
Figs 4.20 & 4.21. Casting sheds offering
shading from the sun; view of casting
procedure.
4 | Palazzetto

66 67
continuity that follows the earlier Palazzetto’s conversion of forces and it thereby – at least externally - loses its
objective power. The force of the ‘combined weight and thrust of the circumferential roof and the dome’101
is
directed through the fan-shaped supports to differently-inclined columns: ‘resultant along the axis of the inclined
columns of the gallery below’102
(figs. 4.14 – 4.16). Any structural logic that remains is additionally shrouded by
clumsy circumferential glazed galleries and circulation (fig. 4.17): ‘its auxiliary functions produced a surrounding
complex that destroys the exterior structural expression, and partially disrupts the interior structure as well...the
approach is more like that of some giant water tank than of a buttressed Nervi dome’103
.
A larger span than the Palazzetto and a huge undertaking - and thereby a more impressive constructive
engineering feat - project was of significance for its constructional magnitude, considering Nervi’s construction
firm was still largely a family-run enterprise. Nervi declared the Palazzo as the ‘most considerable effort
of precasting I have yet studied and built with my construction firm’104
, the ‘most technically, statically and
aesthetically involved parts of the structure such as the dome, the grandstands and the gallery, and the perimetric
columns, were entirely prefabricated from 2,500 elements’105
One thousand-and-eight v-shaped elements
(fig.4.19), of only nine different sizes106
– far fewer than the Palazzetto’s nineteen - formed one hundred-and-forty-
four identical radial waves.
Nervi is confident in the ‘technical achievement and the economic advantages made by the precasting’107
and
understandably proud of the structural expression of the undulating underside that animates the cupola, but is
cautiously subjective of its architectural qualities and mainly praises its prefabricate constructive possibilities:
‘[the] plastic richness which resulted...would not have been possible without the unlimited fecundity of structural
prefabrication...should there be any deficiencies, they result not from limitations imposed by the construction
system, but from the manner in which I applied it’.108
He does, however, concede that with the correct insights
‘Structural prefabrication is a magnificent instrument from which a designer can obtain greatly varied and
expressive harmonies. But in order to exploit it, one must be able to join inventiveness and sensitivity with a
complete mastery of the technical and construction process. A work of architecture based on prefabrication
must originate as such, and its designer must know the methods and limitations involved...that will transform his
inspiration into reality.’109
101. Nervi, 1966, p. 160.
102. Nervi, 1966, p. 160.
103. Billington D P, The Tower and the Bridge: The New Art of Structural Engineering, p. 183.
104. Nervi, 1966, p. 106.
105. Nervi, 1966, p. 106.
106. Poretti & Iori, 200, p. 609.
107. Nervi, 1966, p. 107.
108. Nervi, 1966, p. 107.
109. Nervi, 1966, p. 107.
Fig. 4.30. Boxing event during the Rome Olympics.
4 | Palazzetto

68 69
While the Palazzo demonstrated the scalability of his system, the precursory Palazzetto dello Sport demonstrated
arguably its most befitting application. In 1955 Annibale Vitellozzi asked Nervi to provide an enclosure for a small
‘Sports Palace’ that he had designed, with a clear span of sixty metres and forming a ‘structural element statically
independent of the seating tiers (fig. 4.32 & 4.33), the various services, and the multi-purpose playing field’110
.
Low cost and rapidity of construction were again very important, as the building had to serve as a training ground
for the coming Olympics. Nervi had previously discussed the pre-casting procedure for domes with Vitellozzi,
and expressed that ‘the pre-casting of the dome was, in this case, especially appropriate from all points of view:
economic, architectural, and constructional.’111
The Palazzetto represented an excellent opportunity for the
implementation of Nervi’s strategies. Nervi was by now already in his sixties and well-versed in the Ferro-Cement
construction, but had not yet been able to implement in such an ideal situation. He lamented of the 1952 Thermal
Baths at Chianciano, describing them as ‘unlike domes of revolution, which present repeating patterns and require
forms [moulds] to be built only for a single sector, the many different shapes in the ellipsoidal roof...operated
against prefabrication, and its economic advantage is doubtful’112
. Construction was typically calculated using
the Nervi System, and as sole holders of the rights and specialising in its constituent Ferro-Cement and Structural
Prefabrication procedures, Nervi and Bartoli were awarded the contract. As per usual, it was therefore impossible
to insist on an invited or competitive tender and in this way Nervi’s competitive innovations allowed him both to
maintain control of schedule and quality of execution, whilst profiting financially, in his dual roles as designer and
contractor.
The dome was calculated graphically (fig. 4.31), owing to previous empirical confirmations and visibly expressed
as a Nervian ‘Diagram of Forces’113
. The sixty-metre diameter dome covers around five-thousand metres-
110. Nervi, 1966, p. 104.
111. Nervi, 1966, p. 105.
112. Nervi, 1956c, p. 81.
113. Leslie, T. 2003. ‘Form as Diagram of Forces: The Equiangular Spiral in the Work of Pier Luigi’, Journal of Architectural Education, Vol 57, Issue 2,
(pp. 45-54), p. 53.
4.3 Palazzetto Dello Sport
Fig. 4.31.
Fig. 4.32.
Fig. 4.33.
Fig. 4.31. Working drawing of radial and
concentric reinforcement of the dome; indication
of Tavellone positions.
Fig. 4.32. Floorplan of the Palazzetto. Note radial
butress arrangement.
Fig. 4.33. Section of the dome showing the
animated underside created by the prefabricated
elements.
4 | Palazzetto

70 71
squared, ‘carried’ by thirty-six self-supporting - provided by a second, vertical leg – trestles, following the angle of
inclination of the roof-line, and designed to resist wind loads114
. Fluted edges rising between the raked supports
make use of structural redundancy to allow deeper solar penetration between the forces gathered at the supports.
An eight foot wide, prestressed concrete ring foundation using the Freyssinet system - with two layers of seven
cables, overlapping and anchored at the foot of each support - resists the outward thrust of the dome through
the supports, and allowed Nervi to create the space completely free from vertical load-bearing elements,115
or
monolithic abutments. The supports were cast in carefully-designed timber formwork and left as they were as
they came out of the forms. Nervi, however, was dissatisfied with the quality of the concrete supplier’s finish, and
argued it should have been done better.116
One thousand-six-hundred-and-twenty rhomboidal Tavellone elements (fig. 4.34), of twelve different types - not
including anomalous edge pieces – a greater sum, and of more variation than the Palazzetto – were repeated one-
hundred-and-eight times117
. Questionable diseconomies may have been incurred by the piece’s relative multiplicity
and variation. However these could have been recovered by the reduced scale of the structure and its constituent
pieces, and subsequent site complexities– such as increased falsework rigour and more expensive industrial
plant – both for the pieces’ handling and final assembly. The pieces’ internal componentry are additionally simpler
- forfeiting additional cost and work time - as they did require to have integrated glazing details and stiffening
diaphragms to be worked in to them - as in the Palazzo’s segments. The apertures were fortunately omitted at the
design stage to prevent overheating. Although partially-submerged, the fluted edges and glazed perimeter allow
natural lighting. The inert simplicity of the Tavellone maintain their artisanal purism; objects entirely of their
makers’ hands. However, although it may appear that Nervi applied a different system to the Palazzo as a logical
technical and constructional evolution of the earlier Palazzetto, it is the rhomboidal principle that he applies
thereafter – albeit with different construction cultures and constraints - in Virginia, on the Norfolk Convention
Centre in 1968, and at twice the scale. This again remained the world’s largest concrete dome until 2009.118
The division of the roof into precast elements was a function of its structure: ‘a structure both simple, practical
and of proved economy.’119
The motive causation for the rhomboidal Tavellone morphology was a decomposition
principle determined by a sum of ergonomics, repeatability - affecting speed and cost - and structural
requirements: ‘The resultant shapes provided an efficient distribution of gravity loads along the surface of the
114. Campbell, B. (ed.). 1958. ‘A ‘Big Top’ in Concrete: The Palazzetto Dello Sport, Rome’, Concrete Quarterly, no. 37 (pp. 14-18), p. 17.
115. Deplazes, A. (ed.). 2005. Constructing Architecture: Materials, Processes, Structures [Basel: Birkhauser Verlag AG], p.281.
116. Campbell, 1958, p.16.
117. Poretti & Iori, 2005, p. 609.
118. Norfolk Scope, in Wikipedia <http://en.wikipedia.org/wiki/Norfolk_Scope> [accessed 18 October 2011].
119. Campbell, B. (ed.). 1958. ‘A ‘Big Top’ in Concrete: The Palazzetto Dello Sport, Rome’, Concrete Quarterly, no. 37, pp. 14-18), p.17.
Fig. 4.34.
Fig. 4.35. Fig. 4.36.
Figs 4.34. Drawings of the Tavellone assembly, describing
the generic assembly and internal arrangements:
reinforcement placement; section profile, showing the units’
slenderness; edge detail showing protruding reinforcement;
axonometric showing coffered underside.
Fig. 4.35 & 4.36 Construction images of the Palazzetto,
showing the build up of the prefabricated pieces, and some
monolith concrete overpour.
4 | Palazzetto

72 73
Fig. 4.57. Actual-sized
construction documentation,
typical of the way that Nervi
catalogued site activity.The
images were mounted on pre-
printed annotative cards, and
their details recorded (as per
annotated).
PROJECT
name
CONSTRUCTION
IMAGE
COMPLETION
date
START
date PHOTOGRAPHER
name
ORDER
in series
PROJECT
number
NEGATIVE
number
SLIDE
number
TRANSPARENCY
number
RECORDED
date
PHOTOGRAPHER’s
note
Left-to-right, top-to-bottom: Figs 4.38 - 4.56.
Construction documentation of the Palazzetto.
4 | Palazzetto

74 75
roof, while at the same time providing a geometrically-based resistance to lateral and torsional forces, avoiding the
inefficiency of the Turin apse through regular triangulation.’120
The twelve repeated sizes made use of efficiencies
gained by a ‘repetitive fabricational process in series, with a…changing scale coefficient’121
, which was assured by
the ‘maximum similarity of the shapes of the ‘geometrically self-replicating’ equiangular spiral’122
. This fostered
the workers’ affinity with the fabricational process – principles defined by simple construction drawings (fig.
4.34) and most likely reiterated by Nervi himself - as the composition of the individual elements which although
not identical-sized were geometrically similar and required minutely different fabricational processes. This would
additionally permit the mass-production of the reinforcements. Ergonomics defined the decomposition factor of
the dome, owing to the ‘peculiarity of Nervi’s building site… [which meant] each element had to be small and light
enough to be lifted and easily set into place,’123
and were made to be lifted by two workmen with only rudimentary
means of transporting them (fig. 4.61).
Masonry moulds were built within axis lines drawn on real-scale wooden mock-ups of the Palazzetto sections
(figs. 4.59 & 4.60), and smoothed over with plaster to make the Ferro-Cement moulds. Reinforcement wires were
bent over them, and a ‘doughy concrete mix, made with fine aggregate’124
smoothed over to a thickness of three
centimetres. The upturned edges of the cells provided rigidity whilst handling and setting into place and their
slenderness reduced material cost and made them portable. After curing, the units were raised into place by
central crane (fig. 4.67) and placed on a series of concentric rails fixed to the falsework scaffolding, which were
subsequently fixed on two rails125
. Prefabrication speed was aided by the contemporaneous casting of the same
elements, by creating multiple duplicate mame - ‘daughter’ - moulds, inversely recast from the initial nonna –
‘granny’ moulds.126
Simultaneous teams used the ‘mums’ to create multiple ‘daughters’, which were used in the
construction. Nervi’s process relied on economies gained from this reuse of the moulds and simultaneous castings,
and the process was extremely effective with around thirty blocks a day being created in this way. The completed
pieces were stacked on-site and separated by type (figs. 4.58 & 4.62). The assembly and construction of the dome
itself took only forty days.
The protruding reinforcement wires again united them statically and were welded together, and to additional
reinforcement placed concentrically and radially on top of the completed assembly (figs. 4.64 & 4.65). Concrete
was poured into the channels created by the edge inflexions of the inverted pans and smoothed-over the top (fig.
120. Leslie, 2003, p. 50.
121. Leslie, 2003, p. 51.
122. Leslie, 2003, p. 51.
123. Poretti & Iori, 2005, p. 609.
125. Campbell, B. (ed.). 1958, p.17.
Fig. 4.58 Panorama of the building site, showing
the proximity and amount of Tavellone produced by
on-site prefabrication.
Fig. 4.58. Mock-up section of Palazzetto, erected
on-site, and used to create accurate moulds for the
prefabricated pieces.
Figs. 4.59. Masonry moulds are built using the
curvature of a wooden mock-up of a dome section.
The cheap bricks are stacked and covered with a fine
cement coating.
Figs. 4.61.Stacked Prefabricated units; completed
unit being moved into storage position, using limited
mechanised means.
Fig. 4.62 Tavellone elements stacked; substantially-
completed Palazzetto in the background.
Fig. 4.58.
Fig. 4.59.
Fig. 4.60.
Fig. 4.61.
Fig. 4.62.
4 | Palazzetto

76 77
4.66), uniting the whole roof, to a composited thickness of about ten centimetres. Nervi mused at the accuracy, and
quality of finish – which are remarkable given his means – and the additional savings afforded: ‘note the precision
of the elements achieved by the precasting system which allows one to prepare the elements from a positive
plaster form that can be made as precise as desired. No plaster was applied on the visible surface of the elements;
the joints were stuccoed and the units were whitewashed.’127
Construction was completed in compliance with the
contract, lasting just over a year, from 26 July 1956 until 15 September 1957, and completed – including internal
fixtures - on budget.128
The rhomboidal Tavellone elements – patented at the Turin site in 1950 – the permanence of the Tavellone -
effectively as permanent casting moulds - has created some academic division over their role; whether simply
as decorative formworks for the monolithicisng overpour or as part of a combination in part of a more complex
hyperstatic interaction. The most convincing argument and one that Nervi supports, satisfies a combination;
that they act as a network of ribbed arches - created in the channels of inflexed edges - and that their complex
interaction with the reinforcement embedded in outer surface contributes to a composited structure. The solution
worked and had overcame buckling which was a major problem in thin shell domes, where minor deformations
can change the geometry enough to cause failure and collapse129
. A distinct advantage over other shell builders
‘Nervi had ‘found a way of enhancing the safety of domes without increasing mass; his system in Italy was
economical, and it liberated his imagination to express a variety of spectacular forms.’130
Upon its completion and
the removal of falsework the static behaviour of the structure was diagnosed by means of strain gauges, which
indicated the ‘perfect centering of the loads and, confirmed the accuracy of the preliminary calculations….[and]
theoretical assumptions.’131
The Palazzeto can be seen as a resultant of construction and performance: ‘The resultant forms are … [both]
“diagrams” of the forces of assembly involved [and] records of the constructive logics inherent in the assemblies.’132
The Palazzetto is Nervi’s most successful satisfaction of essential construction criteria, but also architectural.
Viewed globally, the interior underside of the Palazzetto - the rib network created by the troughs - creates a
beautiful architectural motif (fig. 4.68) that is also perceivable as load-distributing lines of force. The constructive
truth and poetry is more within the locality of the individual cells. Whereas the Palazzo’s sweeping undulations
and scale belie the minute workings of the craftsmen who laboured on each segment, the more fragmentary
127. Poretti & Iori, 2005, p.609.
128. Campbell, B. (ed.). 1958. ‘A ‘Big Top’ in Concrete: The Palazzetto Dello Sport, Rome’, Concrete Quarterly, no. 37, (pp. 14-18), p.18.
129. Fischer, R. E. (ed.). 1964. Architectural Engineering - New Structures (Maidenhead: McGraw-Hill, Inc.), p. 38.
130. Billington, 1983, p. 181.
131. Campbell, B. (ed.), 1958, p.17.
132. Leslie, 2003, P. 52.
Fig. 4.64.
Fig. 4.65.
Fig. 4.66.
Fig. 4.63.
Fig. 4.67.
Fig. 4.63. Tavellone nearly assembled.
Fig. 4.64. Placement of the radial and concentric
reinforcements which are used to connect ythe
elements monolithically when concrete is poured
over the completed assembly.
Fig. 4.65. Connecting the protruding reinforcements
of the assembled tiles.
Fig. 4.66. Pouring concret over the assembled roof
and smoothing the mixture into the channels created
by the precast elements.
4.67. Central crane emerging out of the completed
roof.
4 | Palazzetto

78 79
Palazzetto’s success lies is its readability. like Gothic revivalist and 19th Century architectural commentator Viollet
Le-Duc, Nervi’s adoration of the Gothic in his 1956 Publication Aesthetics and Technology in Building is indicative
of his humanism, and would suggest a likelier allegiance with the seriality of the Palazzetto in the analogue he
employs : ‘Every time I have visited a Gothic Cathedral I have been unable to separate the feeling produced by the
grandeur of the space from the enjoyment produced by the discovery of innumerable imperfections of execution
which express the humble love with which the work was carried out and which render even a simple masonry wall
architecturally expressive’133
(figs. 4.70 & 4.71).
Nervi’s rigorous photographic documentation of his constructions remains a valuable artefact (figs. 4.38 – 4.56)
– particularly in exploring his novel prefabrications - as there is little written instruction on their processes. They
frame individual, local procedures and are an important resource in understanding the individual processes and
overall sequence, and many suppositions have been made from photos and drawings of the Palazzetto: ‘their
analysis, in fact, allows us to understand the system itself, and how Ferro-cemento and prefabrication were
combined’134
. This phenomenon is also indicative of the significance of Nervi and his workforce’s embodied
knowledge – relying on observed, proprietary techniques which would remain exclusively associated to Nervi.
Foremost for his own records and meticulously archived (fig. 4.57), Nervi keenly photographed each project and
sought opportunities to revisit them and make improvements. Nervi was also a perceptive entrepreneur, and was
aware that the images could also be used for promotion. The images captured important moments of his patented
procedures - seeming to suggest the boundless complexity and scale that could be achieved with them - and were
also bound for published technical material. He employed professional photographers – and obsessively directed
the images’ composition, bestowing particular emphases135
. There is also a sense of pride in the way in which
Nervi depicts his noble workmen creating his monumental structures: a celebration of the conquerance and
validity of these modern craftsmen and of his procedures. The quality of the images became increasingly intimate
and by the Palazzeto had achieved a very personal, as well as technical quality.
Nervi’s global paternity of design and construction and his workers’ confidence and ability and his belief therein is
evident in the ambitious and fluid contemporaneous and punctual construction schedule: ‘work was progressive
throughout: the surface pours were carried out as soon as a section of dome units were in position and while
placing of the remainder of the units was still in progress.’136
The Palazzetto beautifully exhibits ‘The dualism of
science and craftsmanship...the historical conditions in which the Italian engineering was operating’137
, reflected
133. Nervi, 1966, p. 3.
134. Poretti & Iori, 2005, p. 605.
136. Campbell, 1958, p.17.
137. Iori & Poretti, 2009, pp. 5-6.
Fig 4.68. Interor view of the
completed Palazzetto.
Fig 4.69. Exterior view of the
Palazzetto; inclined columns
buttress the dome, and are clearly
expressive of the forces.
Fig. 4.68.
Fig. 4.69.
4 | Palazzetto

80 81
both in the language of the design, and of its execution. Through his search for efficient – fulfilling cost and speed
desirables - production, Nervi achieved within his milieu a volume, speed, accuracy and efficiency of prefabrication
of static elements that became likeable to a mechanical process; and his workforce surpassed the artisanal and
became industrial agents.
Fig. 4.70. Fig. 4.71.
Fig. 4.70. Interior of the Palazzetto during boxing event.
Figs 4.70. Nevi’s Gothic: King’s College Cambridge (1441), as presented in
Nervi’s book Aesthetics and Technology in Building (1966).
4 | Palazzetto

Artisanal Prefabrication - Nervi's Palazzetto

Artisanal Prefabrication - Nervi's Palazzetto

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