David P. Billington

The tower and the bridge : the new art of structural engineering

What do structures such as the Eiffel Tower, the Brooklyn Bridge, and the concrete roofs of Pier Luigi Nervi have in common? According to this book, now in its first paperback edition, all are striking examples of structural art, an exciting form distinct from either architecture or machine design. Aided by a number of stunning illustrations, David Billington discusses leading structural engineer-artists, such as John A. Roebling, Gustave Eiffel, Fazlur Khan, and Robert Maillart.

Santiago Calatrava’s Alamillo Bridge and the Idea of the Structural Engineer as Artist

The structures of Santiago Calatrava are noted for their adventurous forms, and Calatrava is heralded as a hybrid architect/engineer whose works represent an integration of both disciplines. While there have been a number of publications on the structures of Calatrava, nearly all have focused on the architecture or artistry of them without addressing how well they fulfill the requirements or represent great works of structural engineering. Here a thorough structural analysis of one of Calatrava’s most well known bridges is performed to determine how well it achieves the goals of structural engineering. This provides insight as to how well Calatrava’s works represent engineering as art and what we can learn from his works in the context of great works of structural art.

Structural Art and the Example of Félix Candela

Engineers believe correctly that they are crucial to the nation but usually remain anonymous technicians in the public mind. This misunderstanding is based on three misconceptions that engineers have, which in turn have molded the public’s perceptions and understandings. While the deep problem is the same for each major branch—civil, mechanical, electrical, and chemical—we shall focus here on our own civil engineering profession. First is the misconception that engineering is applied science—that scientists discover new things and engineers take those things and apply them. While this does on occasion help, as a general principle it is historically incorrect. Second is the misconception that the fundamentals of engineering are mathematics and science—that students must study such subjects at a high level to then move to engineering science and finally to engineering itself. While math and science form one part of engineering education, the study of exemplary engineering ideas and works are at least as essential a foundation for engineering education. Third is the misconception that elegance in structural engineering is the province of architects, while engineers ensure that it will stand; only architects can make it a work of art. This argument is contradicted by the most talented structural engineers over the past 200 years whose motivation included appearance along with efficiency and economy. Each misconception is reflected in our own profession, which often seems to have little interest in the recent history of engineering and therefore tends to see engineering as the work of teams of technologists and committees of experts. In short, the neglect of history has the direct effect of dehumanizing modern engineering. There are already some structural engineering professors who sense that missing and critical part of engineering education and are trying to address the misconceptions, which brings us to a most recent illustration: the present Candela project, which has three parts—a college course, a book, and an exhibition. This project grows out of an introductory engineering course first taught at Princeton University beginning in 1974 and enrolling more students than any other engineering course ever offered at Princeton. Through the example of the Candela project, this article illustrates an effective and inspiring way to teach structural engineering not only to engineers, but to anyone interested in learning about our built environment. We use Candela’s “voice” and example to 1 illustrate the central ideas to such teaching, 2 describe the highest achievement possible for a structural engineer becoming a structural artist , and 3 discuss the challenges for the structural engineer practitioner and academic.

Engineering in the modern world: A freshman course in engineering

The authors describe a course designed for engineering undergraduates in their first year that also enrolls a significant number of liberal arts students. The course explains the great engineering events that have transformed American life over the last two centuries: the steamboat and the textile mill, the railroad, the telegraph, and the steel industry, the rise of the electrical, oil, automobile, and aircraft industries, the restructuring of regions such as Metropolitan New York, the Tennessee Valley, and the Colorado River, and finally the growth of information technologies in the last half century. Typically about 70 students enroll in the course and the small classes have about 12 students each. The students do a series of calculations in civil, mechanical, electrical, chemical, and aeronautical engineering that do not require calculus. They write a 3000-word term paper on an engineering object or system, and they take a final examination on the lectures, readings, and calculations. The course has been given five times, and it receives high student ratings.<<ETX>>

Effect of accelerometer mass on the flexural motion of plates

Abstract When the flexural acceleration of a plate is measured by an accelerometer, the mass of the accelerometer tends to reduce the magnitude of the acceleration. This study establishes a simple analytical relation between the accelerometer mass and the corresponding reduction of acceleration. This has been done by studying an idealized diffraction problem for the plate flexural waves. The complex frequency response depends upon the accelerometer mass, the frequency of the flexural wave, the plate thickness and the material parameters of the plate. A numerical filtering method is used to bring an experimental result and a corresponding numerical prediction closer together.

Aesthetics and Economy in Pedestrian Bridge Design

Two common pitfalls of pedestrian bridge design are explored: the idea that a structure that is efficient will automatically be elegant versus the notion that a lot of money must be spent to get a beautiful structure. The drive for landmark bridges has led some engineers to disregard the engineering ethic of economy with some recent footbridges. The Töss Footbridge by structural artist Robert Maillart is shown as a model structure, with Maillarts calculations and a description of the bridges structural behavior presented. Then an extremity on the other side of the spectrum is analyzed: the Turtle Bay Sundial Bridge in Redding, California. The cost escalation and a scientific explanation of the irrationality of the bridge form are presented for this

The Cathedral and the Bridge: Structure and Symbol

23.5 million footbridge. In order to explore both pitfalls in the United States an informal national study of all 50 states was performed. Results from the national study (including costs) are described and interpreted. Three unique structures from this study are presented which are reasonably economical and prove that a so-called signature bridge does not require extreme cost.

Engineering Innovation at Bonneville Dam

When Montgomery Schuyler wrote in 1883 what was perhaps the first critical essay on a work of modern engineering as a work of art (the Brooklyn Bridge), he recognized the cultural similarity between the Gothic cathedrals of the 13th century and the long-span bridges of his own era.1 Just as the cathedrals symbolized the medieval world of stone, so did the bridges of the Industrial Revolution symbolize the new technological world of metal. Yet, while most educated persons of the 20th century will know something of medieval cathedrals and perceive such knowledge as essential to a liberal education, few are familiar with the great modern structures or would accord them a central place in higher learning. Here, we seek to explore two reasons for this cultural neglect. One is related to a misconception about the cathedral itself and the other to a mistaken belief that a deeper understanding of modern engineering is both inaccessible to the non-engineer and without intrinsic cultural value. Our aim is to show how historical study from an engineering perspective can correct such misunderstanding while making the technical questions intelligible to the general public.

Breaking Barriers of Scale: A Concept for Extremely Long Span Bridges

The United States Army Corps of Engineers constructed Bonneville Dam on the Columbia River in the 1930s to improve river navigation and provide hydroelectric power to the Pacific Northwest. This paper demonstrates how the Corps’ approach to the planning and design of the dam’s structures, machines, materials, and processes fostered engineering innovations. These innovations included a new kind of concrete, a portland-pozzolan cement mix that reduced temperature-induced cracking in the massive structure; a new spillway design incorporating energy dissipating structural features; and a new kind of water turbine that enabled efficient power production under widely variable hydraulic flow conditions, adjustable-blade Kaplan turbines. The Corps’ success in the development of innovative engineering designs at Bonneville Dam illustrates the central role of civil engineers in the process of planning, designing, and building major public works.

Building Bridges: Perspectives on Recent Engineering

For each bridge project, span length is an especially important parameter. It is a visual impression of the structure’s technical efficiency and it has a considerable influence on construction cost...