ITALIAN+ENGLISH EDITION
ANNO LXXXIII — SETTEMBRE 2019
ITALIA €12,00
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901
SPERIMENTAZIONI
E RICERCHE STRUTTURALI
BEAUDOUIN ET LODS, CONZETT BRONZINI, FRANCO ALBINI, ICD/ITKE, LEONARDO MOSSOSULLA COLLINA DEL CASTELLO DI LISBONA
ATELIER BUGIO,
RICARDO BAK GORDON,
JOÃO FAVILA MENEZES
901
SPERIMENTAZIONI
E RICERCHE STRUTTURALI
BEAUDOUIN ET LODS, CONZETT BRONZINI, FRANCO ALBINI, ICD/ITKE, LEONARDO MOSSOSULLA COLLINA DEL CASTELLO DI LISBONA
ATELIER BUGIO,
RICARDO BAK GORDON,
JOÃO FAVILA MENEZES
DAL 1928
ITALIAN+ENGLISH +JAPANESE EDITION CASABELLA-JAPAN.JP
60
cASAbellA 90161
Le conseguenze della forma
Marco Biagi
Conosciuto e apprezzato sia in patria che in
ambito internazionale, ma finora indagato
e valorizzato meno di quanto avrebbe forse
meritato, il sodalizio professionale fra Eugène
Beaudouin (1898–1983) e Marcel Lods (1891–1978)
ha prodotto, negli anni Trenta in Francia,
significative innovazioni tecniche nel campo delle
costruzioni metalliche e della sperimentazione
tipologica sull’architettura, nonché opere
autenticamente emblematiche degli ideali
di progresso sociale che hanno alimentato
la stagione “eroica” del Movimento Moderno.
Personalità fra loro antitetiche, ma
complementari, separati da sette anni di
differenza l’uno dall’altro, i due s’incontrano
nel 1922 all’École des beaux-arts, frequentando
entrambi l’atelier di Emmanuel Pontremoli.
Si ritrovano l’anno successivo, dopo il diploma di
Lods, a collaborare nello studio dello zio paterno
di Beaudouin, Albert, occupandosi insieme della
progettazione di complessi d’abitazione a basso
costo nei comuni della banlieue parigina:
segnatamente Vitry (1925), Versailles (1926),
Gennevilliers (1926) e Romainville (1925–27).
Dal 1925 si associano al titolare dell’agenzia, che
si ritira tre anni più tardi, lasciando loro in eredità
consolidati rapporti con la committenza pubblica
degli uffici per le HBM (Habitations à Bon
Marché) e la SALEFN (Société anonyme des
logements économiques pour familles
nombreuses). Per tre lustri, fino al 1940, la coppia
lavora congiuntamente, coniugando e mettendo
a frutto i diversi talenti e interessi dei due soci:
per il disegno urbano e la dimensione contestuale
dell’architettura, Beaudouin, che collabora con
Forestier al piano per l’Havana (1928) e con Prost
a quello per la regione di Parigi (1930–36); per la
razionalizzazione tecnologica della costruzione
e del cantiere, Lods, che sposa e promuove
attivamente la causa della prefabbricazione in
acciaio, mista o integrale, quale via maestra alla
modernizzazione del settore edile e, soprattutto,
strumento chiave per ridurre i costi delle case alla
scala dei grandi quartieri per le masse popolari.
1
schizzo prospettico parziale
partial perspective sketch
«Enfin, le cercle étant le plus simple
des lieux géométriques, doit
également fournir des solutions
constructives extrêmement
élégantes, donc légères, par
conséquent économiques (car dans
les grandes dimensions ce n’est
plus seulement la façon d’utiliser
la matière, mais surtout le choix
de la forme qui importe)».
E. Beaudouin e M. Lods, relazione al progetto di concorso
OTUA per un Nouveau Grand Palais des Expositions, Parigi
1934
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1 AC AD ÉM IE D ’A RC H IT EC TU R E/ C IT É D E L’ AR C H IT EC TU R E ET D U P AT R IM O IN E/ AR C H IV ES D ’A RC H IT EC TU R E D U X X E SI ÈC LE62
Robert Maillart: Massa o qualità? Mass or quality? Masse oder Qualität?
cASAbellA 90163
Nell’arco di poco più di un decennio, i due
giovani professionisti –il compositivo e il
costruttore– bruciano le tappe realizzando una
serie di esperienze pionieristiche e
paradigmatiche che esplorano le molteplici
prerogative e virtualità dell’architettura
industrializzata in metallo. I progetti sviluppati
affrontano le principali funzioni di vita associata
della città contemporanea –residenza,
infrastrutture di trasporto, servizi per
l’istruzione, la cultura, il tempo libero, fino al
monumento– e il variare dei programmi e la
complessità crescente degli interventi sono ogni
volta interpretati come opportunità per affinare
la collaborazione con gli ingegneri e le imprese
coinvolti e approfondire la ricerca, conseguendo
importanti avanzamenti operativi e conoscitivi.
A Bagneux (Cité du Champ-des-Oiseaux, 1927–33),
prima, e a Drancy (Cité de la Muette, 1931–34),
poi, il tema degli alloggi sociali finanziati dalla
Legge Locheur (1928) è, per Beaudouin e Lods,
una palestra ottimale dove iniziare a cimentarsi
con le problematiche e la disciplina della
industrialisation ouverte, della costruzione
standardizzata, per componenti seriali prodotti
in officina, da assemblare a secco, scoperta grazie
all’incontro decisivo con l’ingegnere-impresario
Eugène Mopin. Drancy, in particolare, con il suo
imponente “pettine” di corpi in linea alternati
a torri di sedici piani con ossatura d’acciaio e
rivestimento in pannelli di calcestruzzo vibrato,
costituisce, per l’epoca, un modello inarrivabile
di razionalizzazione della costruzione e del
cantiere, in notevole anticipo sui
grands
ensembles del dopoguerra. In seguito, le
collaborazioni reiterate con gli Ateliers Jean
Prouvé, specializzati nella lavorazione della
lamiera piegata, d’acciaio e alluminio, e con
l’ingegnere civile e aeronautico Vladimir
Bodiansky, inducono i due progettisti non solo a
perlustrare il terreno dell’
industrialisation fermée,
della prefabbricazione chiusa di sofisticati
organismi composti da elementi interamente
coordinati –per esempio nel piccolo prototipo di
casa “smontabile” per il weekend B.L.P.S. (1937–
38) presentato all’Exposition de l’Habitation nel
1939– ma, in aggiunta e in special modo,
a indagare l’opzione di un’architettura
meccanizzata e trasformabile, la cui variabilità
d’assetto funga da moltiplicatore d’efficienza e
versatilità prestazionale del dispositivo edilizio.
Questo, sia attraverso l’articolazione distributiva
e l’ideazione di raffinati meccanismi di apertura
e movimentazione delle facciate o delle partizioni
interne degli edifici, come nel caso dei raffinati
serramenti vetrati
coulissantes messi a punto per
spalancare i volumi delle aule nell’esperimento
“igienico-pedagogico” dell’École de plein air
di Suresnes (1931–35), sia introducendo soluzioni
di parziale automazione del manufatto, come
nel futuribile
bijou mécanique della Maison du
Peuple di Clichy (1935–39): mercato coperto, la
mattina, casa del popolo, la sera, inopinatamente
portato a termine in concomitanza con lo
scoppio della guerra.
È però grazie ad alcuni concorsi indetti,
sempre durante gli anni Trenta, dall’OTUA,
l’Office Technique pour l’Utilisation de l’Acier,
che la riflessione di Beaudouin e Lods sulla
costruzione metallica acquisisce un respiro
diverso e si sposta concettualmente dal piano
dell’uniformazione a quello dell’unicità, dal
pragmatismo tecnologico dell’oggetto
outil
all’eccezionalità dell’invenzione strutturale.
Dopo un primo saggio nel 1933, con il progetto
di un Hangar per aeroplani di forma circolare,
in acciaio e lamiera piegata, sostenuto da un
solo appoggio centrale attorno al cui asse una
generatrice parabolica descrive per rotazione
un’enorme pensilina autoportante a fungo, è con
l’impegnativa competizione per un Nouveau
Grand Palais des Expositions, bandita dall’OTUA
a cavallo fra il 1933 e il 1934, che trova
formulazione la visione più eclatante e
spettacolare elaborata in carriera dai due
architetti parigini. In vista dell’imminente
Exposition Internationale des Arts et Techniques
dans la Vie Moderne del 1937, infatti, il concorso
vaglia l’opportunità di dotare la capitale di un
nuovo palazzo delle esposizioni polivalente,
capace di accogliere le enormi folle veicolate dalle
moderne reti di trasporto di massa e restituire al
5, 6
le torri per appartamenti
prefabbricate della Cité
de La Muette
the prefabricated apartment
towers of Cité de La Muette
7, 8
pianta, sezioni e fotomontaggio
nella natura della Casa
“smontabile” per il weekend
B.L.P.S. progettata con Jean
Prouvé, 1937–38
plan, sections and
photomontage in nature of
the “demountable” B.L.P.S.
weekend house, designed
with Jean Prouvé, 1937–38
2
Eugène Beaudouin e Marcel
Lods all’inizio degli anni Trenta
Eugène Beaudouin and
Marcel Lods at the start of
the 1930s
3, 4
vedute aeree della Cité de La
Muette, a Drancy, 1931–34
aerial views of the Cité de La
Muette, at Drancy, 1931–34
2 5 6 8 7 4 364
Robert Maillart: Massa o qualità? Mass or quality? Masse oder Qualität?
cASAbellA 90165
Paese il primato di una costruzione simbolo del
progresso tecnico come ai tempi della Tour Eiffel.
La richiesta è di una sala colossale di 120.000
mq, a copertura piana e pianta quadrilatera, priva
di sostegni interni e con una campata minima di
250 m lineari. Le ipotesi di localizzazione sono
demandate ai concorrenti. Alla gara sono ammessi
dodici raggruppamenti di progettisti e imprese.
Beaudouin e Lods partecipano coadiuvati da
Vladimir Bodiansky e Désiré Douniaux, ingegnere
dello stabilimento di costruzioni metalliche dei
Frères Paindavoine. La proposta che presentano
è senza dubbio, fra tutte, la più originale e
memorabile, l’unica, forse, come rileva
Georges-Henri Pingusson commentando gli esiti della gara
sulle pagine di «Chantiers» (supplemento tecnico
de «L’Architecture d’Aujourd’hui»), nel giugno 1934,
che non si limita a «trasporre forme conosciute,
anche moderne, in dimensioni di un altro ordine
di grandezza», ma con coraggio e spregiudicatezza
individua una risposta nuova e convincente poiché
conforme alla scala inedita del problema. Scartate
molteplici alternative, la soluzione che permette di
“quadrare il cerchio”, conciliando ragioni statiche,
funzionali ed espressive, si basa, paradossalmente,
sull’adozione di una geometria circolare che
contraddice lo schema planimetrico
quadrangolare prescritto dal bando e costa agli
autori la squalifica del progetto, da parte della
giuria, in sede di valutazione. La forma circolare
permette di trasformare l’immensa copertura in
un leggero velario di vetro, funzionante a trazione
anziché a compressione. La struttura, simile
a un’enorme ruota di bicicletta coricata in piano,
si compone di una corona d’acciaio di 400 m
di diametro sollevata a 51 m da terra per mezzo
di quattro archi ellittici divergenti al vertice e
concorrenti all’imposta. La corona scatolare
sostiene una raggiera pressoché orizzontale di cavi
d’acciaio in tensione, raccordati al centro da un
anello metallico di 15 m di diametro sormontato
da una calotta ribassata in mattoni di
vetrocemento. Il tetto si comporta come una sorta
di cupola rovesciata, sollecitata da forze centripete
lungo il perimetro. La configurazione garantisce
un perfetto bilanciamento dei carichi e il carattere
indeformabile della cintura, esclusivamente
compressa, le permette di sopportare sforzi
notevoli, evitando la necessità di contrappesi
e riducendo ai minimi termini la freccia
d’inflessione delle funi. L’utilizzo di archi al posto
di pilastri per reggere la copertura comporta il
vantaggio di concentrare gli appoggi a terra in soli
quattro punti, liberando da impedimenti il recinto
cilindrico che può pertanto essere aperto,
mediante pareti scorrevoli a tutt’altezza, per metà
del suo sviluppo, sui lati est e ovest, convertendo
di fatto l’edificio in una piazza coperta facilmente
accessibile e rapidamente evacuabile da
moltitudini di persone. Un doppio traliccio di
forcelle al di sopra degli archi fornisce sostegni
cadenzati alla trave torica di bordo, mettendola
in grado di conservare un profilo sufficientemente
sottile ed elegante. Esso ospita, inoltre, nel suo
spessore, rampe che consentono alle automobili
di raggiungere la pista panoramica ricavata al
colmo della cornice e, al pubblico, di distribuirsi
coreograficamente, come un vero e proprio
rivestimento vivente, sugli otto ordini di ballatoi
metallici che irrigidiscono i telai dei grandi
serramenti mobili.
Tralasciando i dettagli, il disegno del nuovo
Grand Palais des Expositions si risolve, in
definitiva, in un puro volume di acciaio e vetro,
nudo e astratto nell’immagine, diafano nella
consistenza a dispetto delle misure, il cui
carattere architettonico, come si legge nella
relazione tecnica di accompagnamento, risiede
anzitutto nella «sincerità dell’espressione
costruttiva». Un aspetto interessante a margine
della vicenda è tuttavia rappresentato dal fatto
che, come si è detto, questo concorso costituisce
uno dei rari episodi, nel percorso di ricerca svolto
prima della guerra da Beaudouin e Lods intorno
alla costruzione metallica, in cui la questione
della forma si pone esplicitamente come punto
di partenza del processo progettuale. E ciò è
inevitabile, secondo i due autori, quando l’opera
supera una certa soglia dimensionale: «Poiché,
nelle grandi dimensioni –essi scrivono– a contare
non è più soltanto il modo di utilizzare il
materiale, ma soprattutto la scelta della forma».
13, 14
l’esterno e la sala di proiezione
al primo piano della Maison
du Peuple di Clichy, 1935–39
the exterior and screening
room on the first floor of the
Maison du Peuple of Clichy,
1935–39
15
prospettiva del progetto di
concorso OTUA per un Hangar
per aeroplani ad appoggio
centrale unico, 1933
perspective of the project
in the competition held by
OTUA for an aircraft hangar
with a single central support,
1933
9–12
veduta d’insieme e particolari
dei percorsi pensili e delle aule
apribili dell’École de plein air
di Suresnes, 1931–35
overall view and details of the
roof paths and opening
classrooms of the Ecole de plein
air of Suresnes, 1931–35
15 9 11 10 12 14 1366
Robert Maillart: Massa o qualità? Mass or quality? Masse oder Qualität?
cASAbellA 90167
16
tavola di inquadramento urbano
del progetto, strategicamente
collocato sull’Esplanade de la
Défense, tra aeroporti e nuove
infrastrutture di trasporto,
quale testa di ponte di una
futura espansione di Parigi
verso ovest, al termine della
celebre prospettiva che dal
Louvre interseca la Concorde
e Place de l’Étoile
urban contextualization
of the project, strategically
located on the Esplanade de
la Défense, between airports
and new transport
infrastructures, as the
bridgehead of the future
expansion of Paris to the
west, at the end of the
famous perspective that from
the Louvre intersects La
Concorde and Place de
l’Etoile
17
prospettiva a volo d’uccello
bird’s-eye perspective
18
vista del modello con gli archi
ellittici che sostengono la
cintura esterna superiore
view of the model with the
elliptical arches supporting
the upper external ring
Grand Palais des Expositions,
Parigi, Francia, 1933–34
Progetto di concorso per un nuovo
Grand Palais des Expositions,
Parigi, Francia, 1933–34
scheda del progetto
progetto
Beaudouin et Lods Architectes
progettisti
Eugène Beaudouin, Marcel
Lods
strutture e impianti
Désiré Douniaux, Vladimir
Bodiansky
impresa
Établissements Paindavoine
Frères
committente
Office Technique pour
l’Utilisation de l’Acier
cronologia
1933–34: progetto
dati dimensionali
120.000 mq superficie coperta
totale
localizzazione
Place de la Défense, Parigi,
Francia
fotografie
Henri Lacheroy, René Picard
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Robert Maillart: Massa o qualità? Mass or quality? Masse oder Qualität?
cASAbellA 90169
19
facciata sud
southern facade
20
facciata est
eastern facade
21
vista della maquette
view of the model
22
spaccato assonometrico
axonometric cutaway
23
pianta delle fondazioni a livello
-17 m, riportante la proiezione
del livello -5 m con il teatro
sotterraneo centrale da 6000
posti e le sue due gallerie di
accesso
plan of the foundations at
level -17 m, showing the
projection of level -5 m with
the central underground
theater for 6000 seats and the
two access tunnels
24
pianta ai livelli 0 e +4 m
plans at levels 0 and +4 m
21 20 19 22 24 23
ACADÉMIE D’ARCHITECTURE/CITÉ DE L’ARCHITECTURE ET DU PATRIMOINE/ARCHIVES D’ARCHITECTURE DU XXE SIÈCLE ACADÉMIE D’ARCHITECTURE/CITÉ DE L’ARCHITECTURE ET DU PATRIMOINE/ARCHIVES D’ARCHITECTURE DU XXE SIÈCLE ACADÉMIE D’ARCHITECTURE/CITÉ DE L’ARCHITECTURE ET DU PATRIMOINE/ARCHIVES D’ARCHITECTURE DU XXE SIÈCLE
AC AD ÉM IE D ’A RC H IT EC TU R E/ C IT É D E L’ AR C H IT EC TU R E ET D U P AT R IM O IN E/ AR C H IV ES D ’A RC H IT EC TU R E D U X X E SI ÈC LE
ACADÉMIE D’ARCHITECTURE/CITÉ DE L’ARCHITECTURE ET DU PATRIMOINE/
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cASAbellA 901
70
Robert Maillart: Massa o qualità? Mass or quality? Masse oder Qualität?
Le alternative
strutturali
Marco Biagi
25, 26
viste del modello dall’alto,
sul particolare del velario
plissettato di vetro, sospeso tra
cavi d’acciaio ad alta resistenza
di 74.400 mmq di sezione,
disposti a raggiera lungo l’anello
perimetrale a intervalli di 18 m
l’uno dall’altro
view of the model from
above, showing the pleated
glass curtain suspended
between high-strength steel
cables with a section of
74,400 mm2, arranged like
spokes along the perimeter
ring at intervals of 18 m
Schematizzate nei disegni riprodotti in
questa pagina –già pubblicati su «La
construction moderne», n. 3, del 1934–
la soluzione strutturale prescelta e quelle
invece studiate e infine scartate da
Beaudouin, Lods e Bodiansky per il
progetto del nuovo Grand Palais des
Expositions presentato al concorso
bandito dall’OTUA nel 1933. Le linee
continue rappresentano le travi maestre,
quelle tratteggiate le travi secondarie.
1 Travatura rettilinea su pianta
rettangolare. Grande incidenza del peso
proprio rispetto al sovraccarico. La portata
delle travi determinata dalle prescrizioni
del programma è vicina al limite di
utilizzo; l’equilibrio è difficilmente
raggiungibile. Aumentando il numero
delle travi maestre si ottengono elementi
lunghi, di piccola sezione, soggetti
a flessione, che comportano perciò
una cattiva utilizzazione del metallo.
Il peso cresce rapidamente, gli sforzi
tendono a convergere al centro della trave.
2 Gli stessi svantaggi del primo caso.
Gli sforzi convergono ancora al centro
della trave. Il movimento è però meno
rapido rispetto al primo caso, con una
certa riduzione dei pesi.
3 Griglia nervata. Possibile riduzione dei
sistemi parassiti; campionatura più
piccola delle travi maestre. Apparizione
di elementi sottili soggetti a flessione.
L’aumento dell’interasse fra le travi
comporta un incremento del sistema
parassita. Circolo vizioso. Il volume
complessivo degli sforzi tende sempre
a dirigersi verso il centro.
4 Stesse caratteristiche del caso 2; in
aggiunta occorre osservare la spinta degli
archi. L’importanza del sistema parassita
non può essere contrastata se non
attraverso la moltiplicazione degli archi,
il che riporta al caso 2. La distribuzione
degli sforzi è stabile, il peso proprio può
essere ripartito uniformemente sulla
lunghezza dell’arco.
5 Stessi svantaggi dei sistemi parassiti.
Riduzione del peso del sistema principale
e migliore utilizzo del metallo. Gli sforzi
si dirigono verso gli appoggi, con
conseguente riduzione dei pesi e
possibilità di luci maggiori. Aumento del
volume dei supporti e tensione dei cavi da
assorbire attraverso contrappesi esterni.
6 Schema poligonale. Le travi maestre
si appoggiano l’una sull’altra. Riduzione
significativa del peso proprio, le travi
sono più leggere verso il centro del
poligono e la luce libera dei sistemi
parassiti decresce parallelamente
anch’essa. Il peso proprio della
costruzione è ripartito sugli appoggi
come nel caso 5.
7 Variante sullo schema poligonale.
Le travi sono sostituite da archi sollecitati
a compressione. Le estremità degli archi
sono raccordate da una cintura
perimetrale che lavora a trazione. Il peso
proprio della costruzione è scaricato sugli
appoggi più che nel sesto caso. Vi è
l’inconveniente del sistema parassita
secondario; l’instabilità a flessione degli
elementi non permette di moltiplicare
gli archi.
8 Cupola rovescia, velario a pianta
circolare su cavi in tensione. La
distribuzione degli sforzi è stabile.
Gli altri pesi sono scaricati sul piano
di appoggio. Una corona esterna bilancia
per compressione la somma delle
sollecitazioni di trazione trasmesse
dai cavi e consente la rimozione dei
contrappesi di ancoraggio esterni.
La portata del sistema parassita è ridotta
al minimo (semplice vetratura).
La moltiplicazione dei cavi assicura una
ripartizione uniforme degli sforzi di
compressione lungo l’anello esterno.
La compressione è assorbita dall’ampia
sezione dell’anello esterno, poco soggetto
a flessione.
25 26 AC AD ÉM IE D ’A RC H IT EC TU R E/ C IT É D E L’ AR C H IT EC TU R E ET D U P AT R IM O IN E/ AR C H IV ES D ’A RC H IT EC TU R E D U X X E SI ÈC LEACADÉMIE D’ARCHITECTURE/CITÉ DE L’ARCHITECTURE ET DU PATRIMOINE/ARCHIVES D’ARCHITECTURE DU XXE SIÈCLE
1 3 5 7 2 4 6 8
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Robert Maillart: Massa o qualità? Mass or quality? Masse oder Qualität?
cASAbellA 90173
27, 28
viste del modello con il sistema
delle rampe perimetrali che
permettono alle automobili di
raggiungere la pista circolare
predisposta in copertura
views of the model with the
system of perimeter ramps
permitting automobiles to
reach the circular track on
the roof
29, 30, 31
pianta, facciata e prospettiva
del progetto di Paul Tournon
e Marcel Chappey, vincitore
del primo premio al concorso
plan, facade and perspective
of the project by Paul
Tournon and Marcel
Chappey, winner of first prize
in the competition
32
il modello nello studio degli
architetti
the model in the architects’
studio
32 27 29 31 30 28ACADÉMIE D’ARCHITECTURE/CITÉ DE L’ARCHITECTURE ET DU PATRIMOINE/ARCHIVES D’ARCHITECTURE DU XXE SIÈCLE
enGlISh
teXtS
cASAbellA 901enGlISh teXtS
103
102
page 20
Veliero: Franco Albini’s celibate machine Roberto Dulio
The Veliero by Franco Albini came
down with a crash, not driven onto the cliffs of a rocky shoreline, but in the architect’s home in Milan. The collapse was caused by the weight of books on the glass shelves sustained by ties, which formed the slender, daring structure of the futuristic bookcase.
The works of Franco Albini in the 1930s and 1940s –installations and furnishings, more than works of architecture, or namely what we would call “design” today, though at the time it was part of a more substantial field of action of architects– are frequently cited as examples of a rigorous functionalism or a strict observance of rationalism. These are vague definitions, never fully clear and thus interchangeable. These works by Albini, to a superficial glance, would seem to jibe perfectly with the rhetorical definition of those dubious critical categories. But their nature, and their very origin, beyond the useful purpose, are extraneous to mere functionality and to any act of rationalist faith, since they find their inspiration in an imaginary oriented by other perspectives.
Albini’s apprenticeship in the studio of Gio Ponti is often reduced to a Novecento interval that comes prior to the birth of the unbendingly avant-garde architect. But instead of seeking formal –and undoubtedly unripe– echoes of that initial phase, it seems worthwhile to reflect on the conception of design Ponti developed in his Milanese workshop, based on an incessant and renewed dialogue of architecture with the other arts, and of the architect with artists.
Also Edoardo Persico, beyond the mythopoeia that clings to his relation-ship with Albini, was substantially poised between art and architecture, those with a background that was utterly heterodox with respect to those spheres themselves. Much has been written about the figure of the Neapolitan critic: whatever the true depth of his personality, his ability to stimulate the imagination of artists and architects remains unchallenged. And, like Ponti, he urged them to heed the suggestions of the artists.
It is not too farfetched to think that Albini fed on the artistic research of his time, also in less conventional expressions and in directions abso-lutely independent with respect to those of his mentors. Given his verbal reticence, we do not know what his references were, but in some of his more experimental works we can clearly see the surfacing of a underly-ing Surrealist temptation. After all, the magazine Minotaure (1933–39),
which was to represent an incisive channel of the spread of that move-ment, did circulate in Italy. Well known to Ponti himself, as well as to Carlo Mollino, it spread in the context of an essentially French-speaking cosmopolitanism. An indisputable go-between for Albini with French literary and artistic culture was his sister Maria, who moved to Paris in
1936. And it seems significant that Carla, the other sister, was involved in the world of the arts, being an illustrator herself.
Therefore certain choices of installation and furnishing presented at the Milan Triennales can be traced back to this subtle influence. Among them, we find the bed suspended at a dizzying height, and the shower in a glass cylinder of the “Room for a Man” at the 6th Triennale (1936); the glass radio (1938); the Mitragliera lamp
(1938–40); the meadow of daisies under a glass floor, the paraboloid aviary and the cableway seats sus-pended in the “Living Room in a Villa” at the 7th Triennale (1940).
In particular, the use of glass, the leaning towards a technical imaginary and at the same time the decontextu-alization of common objects, screened or suspended through transparent crystals, seem to establish a surpris-ing parallel with a famous work by Marcel Duchamp: La mariée mise à nu par ses célibataires, même (1915–23),
better known as Le Grand Verre. A celibate machine to the extent that the
two parts that sublimated the male and female universes through complex symbolism could not come into contact, separated by the two different panels of the same work.
Le Grand Verre was shown at the
Brooklyn Museum in New York in 1926 and 1927, and published in issue 6 of Minotaure (1935) to illustrate an
article by André Breton on Duchamp, after which the Museum of Modern Art of New York presented the exhibition Fantastic Art, Dada, Surrealism (1937–38). It is probable
that Albini saw the article by Breton in
Minotaure –the magazine was easily
available in Ponti’s library, and perhaps in that of «Casabella» or of the sisters Maria and Carla– and that unusual use of glass might have attracted his prehensile eye. The fact remains that the definition of a
celibate machine perfectly fits his Veliero bookcase (1938), so
disastrous-ly unsuitable for the storage of books. Impressed by the ribs, longerons, struts and tie-rods of airplanes – a knowledge and interest borne out by the photographs conserved by the architect himself, probably for the installation of the Hall of Aerodynam-ics in the Mostra dell’Aeronautica italiana at the Palazzo dell’Arte in
Milan (1934), while the immediately prior years were those of a relation-ship of clientele (1931–33) with the famous pilot Arturo Ferrarin – Albini configured a daring device, a sort of hymn in praise of “suspension” through chains and stays, which probably also reflects the images of the utopias of Soviet Constructivism, especially that of Ivan Leonidov. It was Franca Helg, after World War II, who gave the bookcase the Veliero name
(meaning “sailboat”), making the nautical aspect prevail – that of shrouds and masts, which were also part of Albini’s imaginary.
Two reticular struts in ash wood with brass tips, splayed and hinged to a base, also in ash, are held taut by four metal tie-rods –the shrouds– on each side, arranged in pairs and anchored to the base by tensioning mechanisms. The two struts are
joined together in the upper part by two cables, also pulled by tensioners: the upper one functions as a catenary, while the lower one is attached to the central framework of the metal tie-rods, arranged at a distance that would become variable, determined by the reticular holes in the two wooden struts. Small wooden shelves are attached to the tie-rods, and extend crosswise on the width of the base. On these shelves, stabilized by pairs of ulterior inclined tie-rods, made of brass, the shelving is placed in “fervetro,” i.e. tempered glass, which leaves the central part in which the vertical ties pass unencumbered. A complex, unstable system, not so much due to the slimness of the structure –in any case reinforced with respect to the initial, smaller version (13 days earlier!), with just four shrouds and the base reduced to two crossed parts– as to the precarious character of the static behavior and vertical balancing. When the book-case is empty, in fact, the upper cables are put under tension determined mainly by the lateral shrouds. But when the books are inserted, their weight on the shelves pulls on the lowered upper cable, and tends to bring the posts closer together, without encountering resistance to the compression. The increasing proximity of the two struts can only be countered by the lateral shrouds, which however wind up forcefully stressing the base, on the four corners where they are attached. Another point of great stress on the base –com-pression, in this case– is located in the central point of attachment of the hinge of the two struts. These different and opposing stresses tend to make the base flex markedly. To counter this, the base itself was thickened in the section at the center, like a very flattened pyramid. Clearly these measures did not suffice to prevent the collapse of the bookcase, which in the photographs of the time, in any case, is always shown with only moderate loads on the shelves.
In Duchamp’s celibate machine the
female part could not join with the male part; in Albini’s Veliero the static
model of the bookcase without books could not coincide with that of the bookcase loaded with books. Precisely this factor –far more plausible than the legendary high-pitched sound said to have broken the glass and caused the collapse– can be evoked to justify the spectacular débâcle of the striking
aerial structure deployed as a book-case.
The Veliero appears in issue 163 of Domus in July 1941, also on its cover.
In the Milanese living room of the apartment of Albini, on Via De Togni, the bookcase displayed its enigmatic and unstable balance. In a photo-graph probably taken between 1927 and 1933, almost definitely unknown to Albini, we see Le Grand Verre in the
apartment of the American collectors Louise and Walter Arensberg, with the glass broken after shipping following the closing of the exhibition at the Brooklyn Museum. Set in a domestic space, with books in the background seen through the transparency of the work, a resemblance surfaces between the celibate machine of Duchamp and
that of Albini. The parallels between the two works are striking: even if Albini was not aware of Le Grand Verre
by Duchamp, the conceptual conver-gence of the two lines of research would be surprising to say the least. Two immaterial prisms in which the glass, in different ways, supports the suspension of elements –enigmatic objects for Duchamp, books for Albini– that are artificially suspended in the space of an almost traditional bourgeois parlor. The collapse caused by the breaking of the glass also suggests the kinship between the two experimental works.
An initial reworking of the Veliero
–we don’t know if it was prior to or after the spectacular shipwreck– must have taken place before 1948. This is the date of the famous photographic portrait of the architect made by Irving Penn, which would be pub-lished the following year, together with those of other Italian designers, in the American edition of «Vogue», accompanied by a text by Ernesto Nathan Rogers. Next to the portrait of Albini there is also a photograph of the Veliero, defined in the caption as
“his experiment in suspension – a crystal and wire bookcase, handsome as a great bridge.” In the image, with respect to the photographs published in Domus in 1941, we can see that the
wooden base of the bookcase seems to be raised off the ground to permit the insertion of a sturdy structure, probably in metal, that would stiffen the base against the stress generated by the hinge for the attachment of the struts and the tensioners of the shrouds. In the same photograph we can also observe that the vertical tie rods of the shelves are simultaneously attached, in a clearly inconsistent manner, both to the upper catenary and to the lower cable. This second detail can also be seen in another portrait of Albini, shortly thereafter, this time made by Mario De Biasi, who photographed the architect across the shelves of the Veliero.
Only later did Franco Albini hand over the parts of the bookcase to the most expert producer of his furniture, Roberto Poggi, hypothesizing a revision of the project, perhaps in order to put it into production, as had already happened for other “unstable” pieces by Albini, including the rocking chair that appeared in the 1930s among the architect’s experimental furnishings, and was produced by the workshop in Pavia starting in 1959. In Poggi’s workshop, where the Veliero
was stored until 2010, two struts have recently been rediscovered. One of them has the same length as the originals (about 270 centimeters), and was probably made by Poggi himself to test the possible workmanship of the piece. The other is shorter, with a length that corresponds exactly to the upper distance between the two struts of the bookcase (about 200 centime-ters), and was plausibly made in the 1950s by the same craftsmen –un-known thus far– who made the Veliero.
The hinge attachments at the extremi-ties of the bronze tips of this third strut also perfectly accommodate the blade visibly added to the two upper tips of the splayed struts. The third strut, replacing the cables, would have
formed a rigid structure, together with the other two: a strong triangle that would stand up to the stresses of the bookcase. But it was probably Albini himself who discarded this solution, which would have weighed down and disfigured “his experiment in suspension,” already before he called on Poggi.
At the time, the idea of putting the
Veliero into production remained a
mere hypothesis, blocked by the difficulty of making such a precarious construction system stable. It was only after Albini’s death, at the time of the exhibition in Milan at Rotonda della Besana Franco Albini. Architettu-ra e design 1930-1970 (1979), and then
in the exhibition at the Castello Visconteo of Pavia Poggi. Design per un’industria (1986), that Roberto
Poggi, with the help of his son Carlo, a structural engineer, was able to reconstruct the Veliero, leaving it
without books and stiffening the base with iron beams placed below it. This latter device has also been used for the recent reissue of the bookcase (2011), which remains stable only under a modest load (150 kg).
Today the Veliero, after the latest
shipwreck, proudly displays its broken tie-rods. In any case, this object draws on an imaginary universe, indicated starting with the name with which it became famous, that brings together the most refined technical aspects of airplanes and ships; the desire for a lightness that defies the laws of gravity and any functional or techni-cal logic; the adventure of sailing on the sea; the reversal between symbolic form and legitimized meaning of the Surrealist aesthetic. A dream that had to remain suspended on the air and on the waves, without being useful, except as a way of feeding the imagi-nation.
page 46
Experimentation and research on light structures: two possible interpretations Massimo Curzi
Architecture has always spoken of the historical period in which it was made, condensing its thought, the ability to obtain and work with materials, to calculate structures and to take a position on themes being debated in the society in that mo-ment.
One of the biggest problems of our planet today is the recycling of materials, granting them a new life that makes it possible to reduce the quantities of energy used and to postpone the moment of their final elimination. The ability to give every material as many “life cycles” as possible becomes a priority. While for many materials like aluminium, paper and glass recycling seems feasible with a minimum expenditure of energy and minimum environmen-tal impact, for many other materials the energy required becomes more of an issue. Furthermore, if some materials at the end of their life can be burned, polluting the environment but providing us with useful energy, for others this passage becomes impossible, because since they cannot
be burned they force is to bury them as a final solution: this is the case of composite materials. This is why composites –carbon, Kevlar and other fibers– are now among the worst pollutants of our planet. As a result, many university research centers and private think tanks are conducting experimentation to invent ways of treating and transforming these materials at the end of their life cycle. Many of these projects call for the structure that transforms composite materials to be easy to transport, permitting further reduction of energy expenditure in the environ-ment. The transformation of compos-ite materials is addressed in two projects developed by two university departments in Stuttgart that have been working on the theme of light structures for years: the Institute for Computational Design and Construc-tion (ICD) and the lnstitute of Build-ing Structures e Structural Design (ITKE).
Both pavilions are located in the undulated landscape of the park of the Bundesgartenschau in Heilbronn, in the Baden-Württemberg region.
If it is true, as Sigfried Giedion* states, that architecture “is the construction of interior space through structure,” in these two cases precise-ly the structural aspect is the protago-nist with two very different materials that share in the will to reduce the structural component to the essential.
The research conducted by the two institutes moves in two different directions of investigation: the use of a natural and traditional material like wood, and the use of glass and carbon fibers. It is therefore interesting to observe the two projects side by side, precisely to understand their differ-ences, in terms of design and imple-mentation of the structures, but also atmospheric and spatial construction. It is clear that in both cases the use of the computer becomes central: its capacity to calculate and to extend that potential in the numerical control of machinery becomes the most important factor, exploiting the speed of calculation and the precision in controlling details that would otherwise be impossible to produce.
In this pursuit of efficiency of form, the computer can optimize the use of materials, combining the calculation of stresses and deforma-tions with the densification of the material. While in the wooden pavilion this solution gives rise to a change of geometries and dimension-ing of the parts, in the fiber pavilion, as in an ulterior shift of scale, there is the addition of the control of the position of the filaments to the millimeter, optimizing the form even further to its structural efficiency. The fascination with light structures has a deeply rooted tradition in Germany, and in Stuttgart in particular, where the presence of Frei Otto triggered a radical change in the architectural approach from the postwar period on. For this type of architecture, where the method of assembly of the parts becomes the most characterizing detail of the spatial continuum, the points of greatest impact and concen-tration of architectural details are the ground seam, the shape of the borders
of the structure and the roofing technique. The ground seam usually solves a problem of geometry and transmission of weights and tensions in relation to the ground. The shape of the borders reveals their role as load-bearing beams, generally display-ing arched forms and illustratdisplay-ing the structural stress, in a sort of visualiza-tion of the moment diagram. The lightness of the structure and the thinness of the roof surface reduce the distance between interior and exterior, natural and artificial to a minimum, directing the architectural research towards something more sustainable for the environment, in a greater proximity between man and nature.
* Sigfried Giedion, The Eternal Present: The Beginnings of Architecture
(1957).
page 49
BUGA Wood Pavilion from the project description
Its segmented wood shell is based on biological principles found in the plate skeleton of sea urchins, which have been studied by the Institute for Computational Design and Construc-tion (ICD) and the Institute for Building Structures and Structural Design (ITKE) at the University of Stuttgart for almost a decade.
As part of the project, a robotic manufacturing platform was devel-oped for the automated assembly and milling of the pavilion’s 376 bespoke hollow wood segments. This fabrica-tion process ensures that all segments fit together with sub-millimeter precision like a big, three-dimension-al puzzle. The stunning wooden roof spans 30 meters over one of BUGA’s main event and concert venues, using a minimum amount of material while also generating a unique architectural space.
To achieve this goal, the pavilion builds on the biomimetic principle of using “less material” by having “more form”, both on the level of the overall shell and its individual segments. In order to minimize material consump-tion and weight, each wood segment is built up from two thin plates that plank a ring of edge-beams on top and bottom, forming large-scale hollow wooden cases with polygonal forms. The bottom plate includes a large opening, which constitutes a distinc-tive architectural feature and provides access to the hidden connections during assembly. The lightweight building elements are connected by finger joints, which follow the morphological principles of anatomic features found on the edge of sea urchins’ plates. In the assembled state, the shell works as a form-active structure through its expressive doubly curved geometry.
The composition becomes statically stable only when it has been completely assembled. The void inside each element can be exploited, in the lower part, to position a refined LED lighting system, while at the same time the upper part of each element is closed and sealed thanks to a plywood panel glued directly to the framework
on which three other small pieces are placed to permit the deviation, in an organized way, of the outflow of rainwater on the upper surface of the pavilion, towards the three ground supports.
The highly integrative process enables the design and engineering of 376 unique plate segments with 17 000 different finger joints in response to multi- faceted design criteria, from the scale of the overall structure down to sub-millimeter details. Without any loss of precision, this multi-scale approach allows addressing architec-tural and strucarchitec-tural considerations concurrently. Despite the pioneering character of the project, and despite an incredible short development time of only 13 months from commission to the opening, the integrative computational process allows for the careful design of each building element in minute detail. For this, a novel, transportable, 14-axes robotic timber-manufacturing platform was developed by ICD University of Stuttgart and BEC GmbH, and located at the industrial partner Mueller Blaustein Holzbauwerke GmbH for production. The platform includes two high-payload industrial robots mounted on a 20-foot standard container base. The flexibility of industrial robots allows the integra-tion of all pre-fabricaintegra-tion steps of the pavilion’s segments within one compact manufacturing unit. During production, each bespoke shell segment is robotically assem-bled. This entails the placement of preformatted timber plates and beams, their temporary fixation with beech nails, and the controlled application for the structural glue joint between plate and beam. In a second step, the intricate finger-joints and openings are machined into the segments with 300 μm accuracy. From the assembly of beams and plates, to multi-tool machining and sensorial process- and image based quality control – everything happens in a fully automated workflow, controlled by 2 million custom lines of robotic code that were directly exported from the computational design framework. On average, the assembly time per segment is 8 minutes, with the high precision milling taking another 20-40 minutes.
page 55
BUGA Fiber Pavilion from the project description
The pavilion demonstrates how combining cutting-edge computation-al technologies with constructioncomputation-al principles found in nature enables the development of truly novel and genuinely digital building system. The pavilion’s load-bearing structure is robotically produced from advanced fiber composites only. This globally unique structure is not only highly effective and exceptionally light-weight, but it also provides a distinc-tive yet authentic architectural expression and an extraordinary spatial experience.
In biology most load-bearing structures are fiber composites. They are made from fibers, as for example
cellulose, chitin or collagen, and a matrix material that supports them and maintains their relative position. The astounding performance and unrivalled resource efficiency of biological structures stems from these fibrous systems. Their organization, directionality and density is finely tuned and locally varied in order to ensure that material is only placed where it is needed.
The pavilion covers a floor area of around 400 square meters and achieves a free span of more than 23 meters. It is enclosed by fully trans-parent, mechanically pre-stressed ETFE membrane. The primary load bearing structure is made from 60 bespoke fiber composite components only. With 7.6 kilograms per square meter it is exceptionally lightweight, approximately five times lighter than a more conventional steel structure. Elaborate testing procedures required for full approval showed that a single fibrous component can take up to 250 kilo newton of compression force, which equals around 25 tons or the weight of more than 15 cars.
The pavilion is made from more than 150.000 meters of spatially arranged glass and carbon fibers. They all need to be individually designed and placed, which is very hard to achieve with a typical linear workflow and established production technologies. Thus, it requires a novel co-design approach, where architec-tural design, strucarchitec-tural engineering and robotic fabrication are developed in continuous computational feed-back. In this way, the fiber arrange-ment, density and orientation of each building component can be individu-ally calibrated, structurindividu-ally tuned and architecturally articulated, while remaining directly producible.
The building components are produced by robotic, coreless filament winding, a novel additive manufactur-ing approach pioneered and devel-oped at the University of Stuttgart. Fibrous filaments are freely placed between two rotating winding scaffolds by a robot. During this process, the predefined shape of the building component emerges only from the interaction of the filaments, eliminating the need for any mold or core. This allows for bespoke form and individual fiber layup for each component without any economic disadvantage. In addition, there is no production waste or material off-cuts. During manufacturing, a lattice of translucent glass fibers is generated, onto which the black carbon fibers are placed where they are structural needed.
Each component takes between four to six hours to make from around 1000 meters of glass fiber and 1600 meters of carbon fiber on average.
page 60
The consequences of form Marco Biagi
«Enfin, le cercle étant le plus simple des lieux géométriques, doit égale-ment fournir des solutions construc-tives extrêmement élégantes, donc légères, par conséquent économiques (car dans les grandes dimensions ce
