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Understanding the World’s Greatest Structures: Science and Innovation from Antiquity to Modernity

YEAR: 2011 | LENGTH: 24 parts (~31 minutes each)  |  SOURCE: TGC

description:

 Your world is filled with structures that have stood the test of time. That give character to the cities and landscapes in which they’re located. That are visited by millions of people each year. And that capture our wonder for the marvels of engineering innovation and progress. But while structures such as the Giza pyramids, Brunelleschi’s dome, and the Brooklyn Bridge are visual spectacles in and of themselves, they are just as important for the way they were designed as for the way they look.

episodes:

How are ideas for buildings, bridges, and towers transformed from sketches to concrete reality? What are the three essential qualities that make a structure great? What's the difference between seeing a structure and actually understanding it? Discover the answers to these and other questions in this introductory lecture.

Explore how two types of external forces—loads (forces applied to structures) and reactions (forces developed at supports, in response to applied loads)—act on structures such as Kansas City's Chouteau Bridge. Also, learn how these forces are related to the most important concept in engineering mechanics: equilibrium.

Use the Simple Tension Test (pulling on a structural element until it reaches the breaking point) as a gateway to understanding the concepts of internal force, stress, and strength. Then, see these concepts at work in structures such as the Golden Gate Bridge and Athens' Olympic Velodrome.

Materials profoundly influence the form, function, and structure of great buildings, bridges, and towers. Using steel (which is superior in terms of strength, ductility, and stiffness) as a benchmark, compare the structural properties of wood, masonry, concrete, and iron—and see them at work in thousands of years' worth of structures.

One of the most potent human aspirations supported by engineering is to build up. Learn how this has been done from antiquity to the present with columns—structural members that carry load primarily in compression. You'll also learn about buckling: the often catastrophic stability failure that occurs in columns with certain geometric characteristics.

Beams, combining tension and compression, are central to the second aspiration supported by engineering: building across long distances. As you survey beams from the primitive lintel over the Lion Gate at Mycenae to Norway's Raftsundet Bridge, you'll investigate scientific developments and transform your understanding of what makes this structural element possible.

Trusses, the subject of this fascinating lecture, are rigid frameworks composed of structural members connected at joints and arranged into networks of triangles. Learn how they work to stabilize and support a range of structural wonders, including the Brooklyn Bridge and—most famously—the Eiffel Tower.

In this lecture, Professor Ressler introduces you to two final structural elements: cables and arches. The Saint Louis Gateway Arch and the cables of the Golden Gate Bridge are just two examples of breathtaking structural features that also have extensive, occasionally surprising, parallels.

Structures are heavily influenced by the loads they're designed to carry. First, take a closer look at the most important loads structures must resist, including traffic loads and earthquake loads. Then, using the historic iron building at Watervliet Arsenal in New York, analyze how loads are actually transmitted through structural systems along load paths.

Embark on your tour of different types of structures from around the world and across time. Your first stop: ancient Egypt, and the surprisingly complex engineering of pyramids, including the Great and Red pyramids. Your second stop: ancient Greece, where you visit the domed Treasury of Atreus and break down the structural system of the Parthenon.

Learn why the arch is the principal structural feature of ancient Rome. Your detailed case studies range from simple bridges such as the Pont St. Martin and triumphal arches such as the Arch of Titus to massive aqueducts like the Pont du Gard and majestic public spaces like the Baths of Caracalla.

Gothic cathedrals are lasting testaments to the power of a series of sweeping architectural developments in medieval Europe. After examining the roots of Gothic cathedrals in their Romanesque predecessors, focus on several structural innovations—including flying buttresses and pointed arches—at work in places such as France's Chartres Cathedral.

Trace the dome's evolution from the 1st century A.D. to the Renaissance. It's a journey reflected in the increasingly sophisticated domes of three great structures: the ancient Roman Pantheon, the Byzantine-era basilica of Hagia Sophia in Istanbul, and the Renaissance-era dome over the Florence cathedral of Santa Maria del Fiore.

Examine the development of arched bridges during and after the Industrial Revolution. See how the revolutionary Iron Bridge at Coalbrookdale paved the way for the development of science-based engineering. Also, see how science contributed to increasingly sophisticated modern bridges such as Spain's Campo Volantin Bridge.

After learning the science behind suspension bridges, begin your two-lecture look at these structural marvels. Here, relive the "Battle of the Cable," in which 19th-century engineers struggled over whether to build suspension cables from iron chains (as in England's Menai Strait Bridge) or steel wire (as in the Brooklyn Bridge).

In July 1940, the Tacoma Narrows Bridge dramatically collapsed in a steady 42-mph wind. In this concluding lecture on suspension bridges, focus on how the Brooklyn Bridge, the Severn Bridge, and other bridges were designed to combat the second great challenge of these record-breaking bridges: their vulnerability to wind-induced vibrations.

Professor Ressler shows how structural catastrophes produced two bridges that provide a wonderful opportunity to see and understand structure: Scotland's Firth of Forth Bridge and Canada's second Quebec Bridge. You'll also gain insights into the human element of engineering, and the reasons structures turn out the way they do.

How did iron and steel revolutionize building design? Find out in this trip back to late 18th- and early 19th-century Europe and America, where iron-framed structures—such as sheds at England's Chatham Dockyard, New York City's Equitable Life Insurance Building, and Chicago's First Leiter Building—would set the stage for modern skyscrapers.

The human aspiration to build upward reaches its climax with the skyscraper. Learn the story behind America's "great skyscraper race" and the increasingly sophisticated buildings it produced. Among the structural masterpieces you examine in depth are the Wainwright Building, the Chrysler Building, the Willis Tower, and the World Trade Center towers.

Concrete, the world's most commonly used construction material, has been used in buildings that are anything but common. See concrete's versatility at work in an incredible range of structures, including Frank Lloyd Wright's Fallingwater, the Salginatobel Bridge in the Swiss Alps, and Dubai's Burj Khalifa (currently the world's tallest building).

Thin shells are unique structural elements that use curvature—cylindrical, dome-like, or saddle-like—to attain strength and stiffness. See these three types of thin shells used creatively in buildings ranging from St. Paul's Cathedral in London to the Zeiss planetarium in Germany to the Trans World Flight Center at New York's JFK Airport.

The need for roofs spanning large enclosed spaces led to a startling number of new structural systems in the last 200 years. Look closer at long-span structural configurations in places such as the Houston Astrodome, the Berlin Hauptbahnhof, and even the Hartford Civic Center (the collapse of which offers a lesson in the risks of innovation).

Apply old concepts in new ways with this lecture on tension structures, where all the principal load-carrying elements are in tension. Explore noteworthy examples, from the cable-supported roof of North Carolina's J. S. Dorton Arena to the suspended dish roof of Madison Square Garden to the cable dome of South Korea's Olympic Gymnastics Hall.

What happens when you encounter a noteworthy structure that hasn't been included in this course and you want to know more about it? Professor Ressler devotes his final lecture to answering this question; sending you out into the world with suggested strategies for understanding any structure—great or otherwise.