Constructing Building Enclosures

Architectural History, Technology and Poetics in the Postwar Era

Clifton Fordham

• Publisher: Routledge
• Year: 2020
• ISBN:
  9781000081848
• Edition: 1
• Topic: Architecture
• Subtopic: History of Architecture

Constructing Building Enclosures investigates and interrogates tensions that arose between the disciplines of architecture and engineering as they wrestled with technology and building cultures that evolved to deliver structures in the modern era. At the center of this history are inventive architects, engineers and projects that did not settle for conventional solutions, technologies and methods.

Comprised of thirteen original essays by interdisciplinary scholars, this collection offers a critical look at the development and the purpose of building technology within a design framework. Through two distinct sections, the contributions first challenge notions of the boundaries between architecture, engineering and construction. The authors then investigate twentieth-century building projects, exploring technological and aesthetic boundaries of postwar modernism and uncovering lessons relevant to enclosure design that are typically overlooked. Projects include Louis Kahn's Weiss House, Minoru Yamasaki's Science Center, Sigurd Lewerentz's Chapel of Hope and more.

An important read for students, educators and researchers within architectural history, construction history, building technology and design, this volume sets out to disrupt common assumptions of how we understand this history.

PART 1
Framing Enclosures

1
Cladding the Palazzo Lavoro

Pier Luigi Nervi and “The Borderline Between Decoration and Structure”

Thomas Leslie

In July 1959, a committee planning celebrations for Italy’s centenary in 1961 announced a competition for an exhibition structure in Turin, to house exhibits relating to the history of Italian labor. The Palazzo Lavoro was to be vast—45,000 square meters of column-free exhibition space. More daunting, it would have to be constructed in just ten months. Responses to the open competition drew proposals from around the world, in particular a daring shell structure by Turin architect Carlo Mollino. The organizers, however, chose a scheme by Pier Luigi Nervi that, unusually for him, proposed not a dramatic leap of concrete, but rather 16 mushroom-like structural modules: tapering piers topped by dramatically balanced cantilevering roof elements, tapering toward and separated from one another by thin strips of glass (Figure 1.1). Nervi’s selection was controversial; his scheme violated the requirement that the space be spanned without columns. But he argued, successfully, that no single-span shell could be constructed in the time available. His proposal would allow construction to be staged so that each of the 16 piers could be completed on a staggered schedule. This would allow a perimeter enclosure to be assembled and built in parallel with the structure, rather than waiting until a shell was complete and had come up to strength before starting work on the enclosure.¹ Mollino was incensed, but Nervi, as both an engineer and a builder, was the only entrant who could personally guarantee completion within the time allotted.

The commission came in the midst of work leading up to the 1960 Olympics in Rome, which would put Nervi on the world stage as a designer and constructor of breathtakingly large spans imprinted with finely scaled networks of ribs. Often ignored in the glowing praise for these structures, however, was Nervi’s mastery of daylight and the dialogue that his renowned concrete shells carried on with the glazing systems that introduced this light into his spaces. Around the perimeter of the graceful Palazzetto dello Sport, for instance, Nervi detailed a steel curtain wall to match the undulating edge of the arena’s dome, bringing in light under the long-span roof. In a masterfully subtle detail, each bay of curtain wall gently inflects from vertical, sloping slightly outward to meet the dome’s undulating edge perpendicularly.

Figure 1.1Palazzo Lavoro, Turin, Italy. Pier Luigi Nervi/Nervi & Bartoli, 1961. Interior view.

Source: MAXXI Museum.

Even more expressively, the curtain wall around the larger Olympic arena, the Palazzo dello Sport, featured a crisply detailed steel-and-glass skin suspended between the edges of concrete disks that shaped that building’s gently arcing concourse. Punctuated by tri-lobed concrete struts that also serve as wind bracing struts on the interior, the Palazzo’s elegant proportions made it a star; the building featured in Fellini’s 1960 La Dolce Vita, in Michelangelo Antioni’s classic 1962 film L’Eclisse and in a 1964 fashion shoot in Vogue magazine (Figure 1.2).

Nervi developed a language for these cladding systems that defined their places in his buildings’ structural hierarchy. While handling fewer loads than concrete structures, cladding systems nevertheless bear the loads of their own materials and of wind. They therefore formed fertile territory for Nervi’s interest in expressive structural form. Like the lifting and bracing fork-shaped buttresses that held the dome of the Palazzetto above its seating, elements of building cladding could, Nervi believed, be part of a grammar of static shapes and of relations between elements.

The wind braces of the Palazzo provide an example of Nervi’s philosophy (Figure 1.3). They are deepest at the center of their spans, where the bending moment induced by wind loads on the glass outside is greatest. The detailing at their ends conveys that they are simply pinned to the concourse roof and floor. In a similar display, they taper to meet these elements, revealing that the main structure braces itself against any circumferential torsion, or radial thrusts, leaving these components elements alone to support and to resist the wind loads of the curtain wall. These are minor elements, and these detail choices are subtle, but they are important in revealing to the passerby how they operate and the hierarchy of their performance in relation to the whole. For Nervi, these details were fundamental communicative tasks and the basis of what he termed “structural architecture,” the linguistic resolution of elements into systems that can be read, visually and kinesthetically, by the layperson.

Figure 1.2Palazzo dello Sport, Rome, Italy. Pier Luigi Nervi/Nervi & Bartoli, 1960. Views of curtain wall from interior, from Vogue, April 1, 1964.

Source: Conde Nast.

Figure 1.3Palazzo dello Sport, Rome, Italy. Pier Luigi Nervi/Nervi & Bartoli, 1960. Shop drawing of precast curtain wall support.

Source: CSAC, University of Parma.

The Challenge of the Palazzo Lavoro

In Nervi’s words, the commission for the Palazzo Lavoro put forth “an architectural, economic, and constructive problem of unprecedented complexity.”² His solution broke the complexity of a large span—525′ square—into 16 repetitive units, allowing for repetitive formwork, standardization of components and telescoping of construction and fabrication time.³ Each unit consisted of a tapering concrete pier, rising from a cross-shaped plan to a circular cross section; Nervi would later explain this as a programmed structural section, offering stability at the base and flexibility at the top. To achieve these sections, Nervi relied on twisting timber formwork based on ruled surface principles—the edges of the thin timber formwork strips reified the straight lines of a mathematically conceived ruled surface, while the twisted timber itself formed a surface that negotiated between the gradually changing angles of the lines.

Nervi first used a version of this principle at the UNESCO secretariat in Paris to produce that structure’s sloping, haunched piers at the ground floor. He divided the formwork for each 21 m pier into five sections, each of which could be formed by prefabricated, reusable molds of twisted timber. Each mold could be disarmed as each pier came up to strength and re-used on the next one to be built (Figure 1.4). Above these piers, Nervi was forced by time constraints to change his original proposal, of concrete roof forms. Recognizing the difficulty in forming and scaffolding such broad cantilevers, he re-conceived them in steel, hiring engineer and fabricator Gino Covre to direct their calculation and production. This allowed rapid erection immediately behind the crews forming the piers, but it also introduced a new material into Nervi’s structural oeuvre—while he had designed steel elements in his previous structures, nowhere had the material played such an important role in the static performance of one of his long spans.⁴

Figure 1.4Palazzo Lavoro, Turin, Italy. Pier Luigi Nervi/Nervi & Bartoli, 1961. Construction view showing staging of pillars and steel roof.

Source: MAXXI Museum.

These 16 mushroom roof elements were to be structurally independent; glass-covered gaps between them delineated the overall structure. But, more importantly, these separations allowed each mushroom to rotate slightly under uneven loading or wind pressure, reducing potential bending stresses within the roof structure. This structural freedom, however, left a serious issue at the perimeter, where the program required full environmental enclosure. Given the movement possible with each carefully balanced steel roof element, how could a cladding system be supported while also allowing for such dynamic behavior?

Gio Ponti, a multi-dimensional architect and designer, was ultimately hired to design the interior exhibitions for the Palazzo. While he and Nervi did not fully agree on the relationship of the exhibits to the punctuating structure, they were both adamant that the pavilion had to be as transparent as possible, to broadcast the contents of the interior to passing festival attendees and to serve as an illuminated beacon for the exposition grounds at night.⁵ Nervi thus conceived the entire cladding system as a tautly stretched glass curtain wall, maximizing visibility while minimizing weight. This wall would cover two zones, separated by a gallery mezzanine level 3 m above ground. Below this, a standard storefront system allowed for entrance doors as well as solid and glass panels, depending on the functions behind. Above, however, this left a 19 m span from mezzanine to roof, a height that promised significant wind forces, and a considerable load from the weight of the glass itself. Further complicating the skin’s conception, Ponti and Nervi both recognized the need to balance transparency with solar control—the developing exhibits featured changes in light levels and color that risked being washed out by too much direct sunlight.

Having expa...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Contents
• Notes on Contributors
• Acknowledgments
• Introduction: Enclosure Expanded
• Part 1 Framing Enclosures
• Part 2 Assembling Constructions
• Index