This post reflects some of the storyline that Prof. Adriaenssens, invited by the Broodthaers Society of America, will be telling on Tuesday, March 28, 6:30–8pm at Hauser & Wirth Bookshop and Roth Bar, 548 West 22nd Street, New York, NY 10011.
The efficiency of shells is often exemplified by examples of nature. In particular the avarian egg shell and the sea shell come to mind. A large chicken egg for example is about 4.5cm and has a typical shell thickness of 0.05mm ( slenderness ratio of 900) and could theoretically sustain a load of 14kN (that is the weight of about 14 American football players). The shell can be very slender and sustain high distributed loads because its form follows the flow of internal loading. To further stiffen against impact loading, some shells in nature are equipped with corrugations like many tropical sea shells.
Civil shell structures mostly originated in Germany in the beginning of the 21st century, spurred by development of analytical “shell” theory and reinforced concrete. Their evolution in that century can be marked by 3 phases. These phases also happen to span the biological life of Belgian artist Marcel Broodthaers (1924-1976) who is , among other projects, known for his assemblies of shells of eggs and mussels.
In this post, I briefly describe the history of civil shell design and construction in Belgium in the 20th century and in particular I focus on the work of the civil engineer Andre Paduart (1914-1985), who operated in the same time and geographical space as Marcel Broodthaers.
The early shell period 1912-1940: utilitarian cylindrical shells in the Port of Antwerp
The initial shell designs were entirely envisaged, analyzed and built by engineers, interested in spanning large spaces without intermediate supports in the most material efficient manner. The German contractor firm Dyckerhoff and Widmann AG first developed analytical theories to analyze shapes, related to domes (spheres) and vaults (cylinders). Utilitarian spaces such as warehouses and aircraft hangars were roofed with these shells. A fine example of such shells can still be found on Kaai 105, 107 and 109 at the Albert Dock in Antwerp, a port city in the North of Belgium. The fast port reconstruction after the destruction of the Second World War demanded warehouse structures and construction techniques that were cost-effective. The Belgian structural engineer Andre Paduart designed and built 465m of such warehouse sheds along the Docks in Antwerp. Each shed has 31 bays, covered with a reinforced concrete 8 to 12cm thin cylindrical shell. The shell had a transverse span of 15m and a rise of 3m. To allow daylight to flood the shed, a rectangular opening (40m x 3m) ran along the crown of the cylindrical shell in the longitudinal direction. To economize, the formwork was re-used each week to build another bay. These shells still exist today and are structurally significant because they have no edge beams and no permanent tie rods to resist the transverse shell trust.
A few international other significant shells of that period include MarketHall Leipzig (Germany, 1927 – 1930, Dyckerhoff and Widmann AG), Orly Hangar (,France, 1921, Eugene Freyssinet)
Second Period 50’s and 60’s: Iconic shells realized for their visual expressiveness at Expo ’58, Brussels
The increasing body of knowledge in shell theory and construction, initially led the formal language for shells. Internationally, the richness of shells from that era have widely been showcased by the ribbed spherical and cylindrical shell forms of Pier Luigi Nervi (1891-1979) and the hyperbolic paraboloid (hypar for short) thin shells of Felix Candela (1920-1997). In 1958 Candela built his masterpiece Los Manantiales, a radially arranged assembly of expressive hypars. In the same year the capital of Belgium, Brussels, held Expo ’58, the first major World’s Fair after World War II. Iconic pavilions and installations, built for this grand event, included the Atomium and the Philips Pavilion, an arrangement of nine hypars designed by Le Corbusier. Lesser known are the other shells that populated the Expo’58 site including the hypar information kiosk (designed by J.P. Blondel, the vaulted United Nations Pavilion and the semi-spherical Tuilier restaurant.
In 1957, Broodthaers was a manual laborer on the construction site of the Expo 58 “Avec l’intention de [se] rapprocher des hommes qui la construisent ” [“to get closer to the people that are physically making the Expo”]. In 1958, he published “Another World,” an essay on The Atomium published in Le Patriote illustré, vol. 74, No. 10, Brussels, 9 March 1958, p. 389.
Our attention goes out to a more sculptural shell “the Arrow” which dominated the Expo ’58 site. Andre Paduart received from the Belgian government a commission to design and construct a symbol exemplifying the “victory of civil engineering over nature”. The Arrow, a thin reinforced concrete thin folded plate cantilevered 80m and was balanced by a thin 29m span shell on three supports. The folded plate had a tickness of only 4 cm at its tip and the shell on three supports had a thickness of only 6cm. The cantilever supported a pedestrian bridge that overlooked a scale map of Belgium. This map showed civil engineering works! For this incredible engineering tour de force, Andre Paduart and the architect of the project received the 1962 Construction Practice Award of the American Concrete Institute.
In 1964, Marcel Broodhaerts showcased his work “Casserole and closed mussels” and stated ’The bursting out of the mussels from the casserole does not follow the laws of boiling, it follows the laws of artifice and results in the construction of an abstract form’
Third Phase 70’s and 80’s: Decline of shell structures and folded plates at the Groenendael Hippodrome
In the 70’s the architectural interest in the expressiveness of shells faded. At the same time, the cost of labor involved in constructing shells, became uneconomic and other long-span structural solutions were favored. To cover the grandstand of a hippodrome near Brussels, Andre Paduart designed and constructed a 13.5m cantilevering folded plate with a thickness ranging from 7 to 12cm only. The roof had a width of 106m and no expansion joints. The roof is reminiscent of Eduardo Torroja’s (1891-1961) Zarzuela hippodrome and Hilario Candela’s Miami Marine Stadium. In 2012, these folded plates were demolished.
In 1976, Marcel Broodthaers is buried at the cemetery of Ixelles, Brussels at a distance of 100m to the University Libre de Bruxelles where Andre Paduart taught thin shell theory.
Author: Sigrid Adriaenssens
I would like to thank Joe Scanlan for co-constructing the storyline and Paul Van Remoortere for providing valuable information.
Espion, B., Halleux, P., & Schiffmann, J. (2003). Contributions of André Paduart to the art of thin concrete shell vaulting. Proc. of the 1st Int. Congr. on Construction History, 829-838.