Professor at Lehigh University

Professor at Lehigh University >

The Rise and Fall of the Gothic Cathedral
Episode 12 of Understanding the World's Greatest Structures
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:…
Construction Revolution—Arches and Concrete
Episode 6 of Understanding Greek and Roman Technology
Learn how the physics of the arch solves the problem of the tensile weakness of stone. Then see how standard bricks and concrete greatly simplify and reduce the cost of monumental building. These technologies were the key to Rome's construction…
Learning to See and Understand Structure
Episode 1 of Understanding the World's Greatest Structures
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?
From Wood to Steel - Properties of Materials
Episode 4 of Understanding the World's Greatest Structures
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…
The Global Challenge to Educate
Episode 1 of How the World Learns
Borrowing or benchmarking one national education system against another is not necessarily a remedy or the most useful analytical tool for educational reform, yet these are among the most common approaches. Begin to understand why this approach falls short as…
Three Great Domes: Rome to the Renaissance
Episode 13 of Understanding the World's Greatest Structures
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…
Loads and Structural Systems
Episode 9 of Understanding the World's Greatest Structures
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…
The Most Celebrated Edifice—The Pantheon
Episode 9 of Understanding Greek and Roman Technology
Conclude your study of great classical-era structures by examining the greatest of them all: the Pantheon in Rome. Imitated but never equaled, this temple to all the gods incorporates Greek as well as quintessentially Roman architectural features. The stupendous dome…
The Beauty and Versatility of Modern Concrete
Episode 20 of Understanding the World's Greatest Structures
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…
Evidence-Based Policy Making in Education
Episode 4 of How the World Learns
Delve into the question of why evidence-based educational policymaking has become a global phenomenon by looking at the way data is used to shape what teachers and students do in the classroom. See how governing bodies can bureaucratize the ways…
Egypt and Greece: Pyramids to the Parthenon
Episode 10 of Understanding the World's Greatest Structures
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…
Trusses: The Power of the Triangle
Episode 7 of Understanding the World's Greatest Structures
Trusses, the subject of this fascinating episode, 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…
The Glory of Rome in Arches and Vaults
Episode 11 of Understanding the World's Greatest Structures
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…
The Science of Structure - Forces in Balance
Episode 2 of Understanding the World's Greatest Structures
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…
Building Up: Columns and Buckling
Episode 5 of Understanding the World's Greatest 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:…
Cables and Arches: The Power of the Parabola
Episode 8 of Understanding the World's Greatest Structures
In this episode, 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,…
Technology in the Classical World
Episode 1 of Understanding Greek and Roman Technology
Begin your exploration of ancient Greek and Roman engineering by probing the technological edge that allowed the Greeks to beat the Persians at the Battle of Salamis. Then survey the aims of the course and preview an impressive piece of…
Internal Forces, Stress, and Strength
Episode 3 of Understanding the World's Greatest Structures
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…
Stone Masonry Perfected—The Greek Temple
Episode 4 of Understanding Greek and Roman Technology
Focus on the classical-era temple, one of the crowning achievements of Hellenic civilization. Where did it originate? Why are the many examples so architecturally consistent? What were the principles of Greek temple design? And what were its structural limitations?
Connecting the Empire—Roads and Bridges
Episode 11 of Understanding Greek and Roman Technology
At its height, the Roman Empire had 75,000 miles of public roads, organized into a system that incorporated way-stations, milestones, triumphal arches, and upward of 1,000 bridges. Investigate how the Romans created this impressive transportation network, parts of which have…