The Pantheon Paradigm for Structural Design: Faced in Stone; Formed in Concrete

Part I – Pantheon Paradigm

The image of Rome’s Pantheon resonates and re-emerges throughout architectural history. The assemblage of classical vocabulary from the temple portico entrance to the dome-covered rotunda is witnessed in numerous landmark examples. From the 1789 Panthéon of Paris, to Thomas Jefferson’s Rotunda at the University of Virginia in 1826, to the British Museum reading room of 1857, to Washington D.C.’s Jefferson Memorial in 1938, the direct and indirect inheritance from the Pantheon design in western architecture is perhaps immeasurable. In achieving this visual lineage, a parallel history of structural design and construction can be traced. This physical history adds dimension and material to what lies beneath the surface, and sheds light on the human ingenuity and exertions integral to the complex story that is the ongoing life of the Pantheon. Building from within the context of structural design and construction precedent, the infusion of contemporary technologies and methods creates both opportunity and risk in advancing the dialogue with architecture’s past. 

This project offers a framework of study that advocates for three over-arching goals: first, for a broadened definition of structural design that expands the study of engineering history and preservation engineering in the education of design professionals; second, an increased emphasis on the visual aspects of structural design and interpretation; and third, for an emphasis on communication and shared literacies in an integrated design process. Focus on the Pantheon and its lineage highlights the challenges of perception, interpretation and translation for preservation engineering, distinguishing the form of literal structural function from the symbolic image of surface.

Part II – Structural Design, Broadly Defined

The term “design,” particularly in the engineering world, connotes developing plans for building something new. For engineering education in the United States, the nearly exclusive focus on new construction leaves a significant gap in student preparation for entering a building profession where design efforts are frequently challenged to integrate with existing constructions; this is particularly true for building within an urban environment. This academic focus fuels an unsustainable economic model, where we would be setting ourselves on a course of temporary/disposable architecture in which we walk away from our aging architectural resources or buy into a recurring cycle of demolition and new construction. Arguably even greater than the economic and environmental problems with this model of consumption, is that the model is culturally unsustainable. When we acknowledge the extent of human energy, intellect and art that goes into the creation of our built environment, the recurrent destruction of these works must inevitably be perceived as a loss.

In architectural design and assessment, people translate the visual experience in multiple ways – some use words, some draw, and some use numbers. These represent the languages with which we render meaning and determine value, be it aesthetic, social or physical. Whether assessing an existing construction or envisioning one anew, the design professional must access multiple languages to interpret the physical signs and symbols that make up the visual language of architecture. Acknowledging this intrinsic nature of communication within the building arts and industry, language and translation can provide a conceptual framework for both education and practice. 

In this context, we can consider three broad categories of language: Speech, Graphics and Mathematics. The three languages may be employed to look forward in time, toward a vision for new design, or to look backward in time, to envision a history of performance for the present assessment of existing construction. The negotiation between owner, architect and engineer moves between speech, graphics and mathematics in an iterative design or evaluation process. The ability to achieve fluency in each language, to successfully mediate the inherent approximations and modifications with each translation, becomes a most valuable and marketable skill for both engineer and architect.

Part III – Jefferson and the American Translation

Work in this section will continue after my return from Rome, based upon direct work with Jefferson’s University of Virginia Rotunda and the Virginia State Capitol.

Part IV – Technical Eye

The architecture of ancient Rome is rooted in a vocabulary of structural forms, which, in their surviving stones, communicate the strength of Roman construction and of the Roman Empire. Column, lintel, arch, vault, buttress – the expression of each form visually confers a sense of strength and stability in their literal structural function, and contributes to architectural compositions that have evolved in symbolic meaning over time. The effects of time, nature and society present a reshaped and fractured history on the surface of these stones – sharp edges become rounded, details blurred, planes shifted, and solid surfaces cracked. I’m thinking about how we read this physical history of the built environment, how the nature of our readings change with historic changes in the architectural and structural use of stone, and how our ability to “read strength” profoundly influences historic preservation and the emerging field of preservation engineering.

Multifaceted structural readings in architecture are perhaps nowhere more powerfully demonstrated than in Rome, where ancient through modern works are uniquely situated side by side – an urban context spanning the broadest range of building technique, where the influence of time is eminently palpable. Part of my project explores structural expression in iconic classical works and traces their evolving representation through comparisons with the modern works of EUR (Esposizione Universale Roma), which makes direct visual reference, through architectural composition and structural symbol, to the ancient paradigms. EUR was created during the Fascist regime of Mussolini with the explicit architectural goal of communicating strength in at least three ways: socially, expressing wealth and prosperity through the grand project scope; politically, representing national power by linking the current government to the ancient Roman empire with specific reference to its iconic buildings and symbols; and physically, with stone surfaces and structural vocabulary manifesting the capacity and durability of Roman constructions, both past and future (Vittorio Cini, General Commissary of the Ente EUR, 1937). Libera’s Palazzo dei Congressi, a modern abstraction of the Pantheon, offers potent lessons about form and surface for perception and preservation.

Within the modern context of EUR however, this communication of strength is often mediated through cladding systems, where the goal of longevity finds challenges in the tenuous connection between surface and structure. This “second-order” structural expression, dependent upon and responsive to the primary structure within, presents new patterns of performance over time. The facade cannot stand without its intrinsic relationship to the structural backing. If we look at the curtain wall and cladding systems as an example, one could see this as a clear physical manifestation of the separation of, or specialization within, engineering and architecture. The seemingly neat separation of roles risks leading us down the path of less communication. However, the communication between cladding and structure, between architect and engineer, is essential to the successful performance of the building. The connection systems between cladding and structure often represent the weak link in modern design, with design responsibility ambiguous, with movement accommodations needed, and with careful consideration of durability given the dynamic and transitional environment within the exterior wall construction.

Specialization in architecture and the separation of roles has inspired interest and lamentation for well over a century, however the need for communication between these characters and their respective concerns remains constant. As early as 1874, Eugène-Emmanuel Viollet-le-Duc portrayed the separation of engineer and architect with a parable of twin masons, whose “narrow-minded” father made them divide their work for the sake of efficiency, one working only above the ground while the other working only below. The twins who had been happy working together soon began to quarrel.  Lewis Mumford offered his 1924 perspective on the World’s Columbian Exposition of 1893, with similar concerns for the division of interests:

“Behind the white staff facade of the World’s Fair buildings was the steel and glass structure of the engineer:  the building spoke one language and the ‘architecture’ another.  If the coming of the skyscraper had turned masonry into veneer, here was a mode of architecture which was little but veneer.”

Lewis Mumford, 1924

The question posed here is given the ultimate shared effort in the preservation and design of our built environment, how do we meet the challenges in communication posed by specialization, both within the profession and within academia.

Part V – Pope, Pei and the National Gallery of Art

“Material comes second; form comes first.”  I.M. Pei (1978)

The path of visual inheritance is clear when considering Jefferson’s UVA Rotunda, or Pope’s Jefferson Memorial and National Gallery of Art.  However, when considering these works within the history of concrete design and construction, the second-generation influence on I.M. Pei’s East Building for the National Gallery (1978), which consciously reflects Pope’s West Building in surface material, finds a surprising connection with the original source of the Pantheon, based upon both form and material.  Pei’s virtuoso work in architectural concrete, in collaboration with the structural engineering firm of Weiscopf & Pickworth, features triangular coffered slabs and iconic concrete beams and lintels, and expresses the advances of reinforced and prestressed concrete design in the horizontal plane.

Faced in stone and formed in concrete, the East Building embodies the many challenges of preservation engineering.  With design of stone cladding representing masonry construction paired with form made possible by reinforced and prestressed concrete, current preservation of the stone skin highlights the complex relationship between architectural surface and structure.  In his distinguishing of characteristic Greek and Roman architecture, Viollet-le-Duc touches on this very question of the separation of surface and structure, of clothing from the man, offering a valid lesson of compatibility and communication that still applies today:

From Viollet-le-Duc’s Lectures on Architecture, 1875

“In Greek architecture the visible external form is the logical result of the construction; Greek architecture may be best compared to a man stript of his clothes, the external parts of whose body are but the consequence of his organic structure, of his wants, of the framework of his bones, and the functions of his muscles.  The man is so much the more beautiful as all the parts of his body are in harmony with their purpose, and, with nothing superfluous, they yet suffice for their functions.

Roman architecture, on the other hand, may be compare to a man clothed:  there is the man, and there is the dress; the dress may be good or bad, rich or poor in material, well or ill cut, but it forms no part of the body; if well made and handsome it merits examination; if it restrains the man’s movements, and its shape has neither reason nor grace, it is unworthy of notice.”

Part VI – Broadening Visions

From Viollet-le-Duc’s How to Build a House, 1874

“... Seeing that all this would not put me in a speedy way to master my profession, and being so fortunate as to have a few hundred pounds left me, I resolved to travel – to study architecture in actual buildings, and no longer in those shown me on paper.  I set myself to observe, to compare, to see practical men at work, to examine buildings that were crumbling to pieces, that I might discover in anima vili the causes of their ruin.”

The conclusions of this study are multi-faceted in detail, yet singular in spirit. The academic study of preservation engineering merits inclusion in the curricula, and the curricula are lacking representation of an important and growing part of the profession without it. The value of existing and historic engineered systems must be understood and communicated for the sustainable growth of our built environment. The skills and training of the preservation engineer encompass ways of seeing and ways of translating, in words, pictures and numbers. In the spirit of the above quotation from Viollet-le-Duc, we must let students of engineering, architecture and preservation see, and learn from, what we already have. This will broaden the scope of their vision and also broaden the base from which they learn to design and create for the future.

National Gallery of Art Capriccio 01

National Gallery of Art Capriccio 02

Stone and Statics

Square Colosseum Evolution

Virginia Capitol Cutaway

Arch - Flat and Segmental

Ellis Island - Baggage & Dormitory Building Concept

Pantheon Sketch

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