Building Bridges: A Feat of Engineering and Artistry

When was the last time you crossed a bridge?

If you live in Philadelphia, chances are it was today—maybe even several times. With more than 500 bridges crisscrossing the city, they are part an integral part of daily life. In a city defined by its rivers, bridges make possible the connections between people.

Where traditional bridges connect two sides of a chasm, architect and structural engineer Masoud Akbarzadeh has taken this challenge further, constructing one out of a material that conventional wisdom says should not be used for a bridge at all: glass.

The result is a breathtaking 30-foot-long structure composed entirely of interlocking hollow glass units. At first glance, the bridge appears impossibly delicate, an ethereal span of translucent polygons that shimmer under light.

“Bridges are more than mere structures spanning rivers and chasms; they symbolize physical and metaphorical connections,” says Akbarzadeh, an associate professor of architecture at Weitzman. “As pathways between two points, they embody the human endeavor to overcome distances and unite disparate realms. Yet, beyond their practical utility, bridges serve as potent symbols of solidarity, understanding, and collaboration.”

The Glass Bridge eliminates the need for traditional reinforcements like steel, instead harnessing glass’s strength within a compression-dominant structural form.

“All these pieces alone, hollow glass units, might seem quite brittle—and they are,” Akbarzadeh says, “but depending on how you design to put these glass units together, they start relying on each other, and the units’ assembly establishes a path for the load to be transferred efficiently. Thus, the bridge gains strength as a whole.”

Akbarzadeh likens this notion of the pieces forming a greater, more powerful whole to human society, noting that “for a better-functioning society, we need to rely on each other. We need to trust each other, and together, only with transparency, we can work and unite to create an advancing world that serves the people in it.”

He and his team fabricated the bridge over the course of three weeks in 2024. According to Boyu Xiao, a 2024 Weitzman master of architecture graduate who currently works as a research assistant in Akbarzadeh’s Polyhedral Structures Laboratory, “the process was a test of both engineering ingenuity and sheer physical endurance.”

The bridge, formally known as “Glass Bridge: The Penn Monument for Hope,” stands tall, on display at the Corning Museum of Glass, where it will remain until September 1. Leading up to its unveiling at the Museum, Greenhouse Media met with members of the team and documented the process of fabrication for an upcoming documentary.

But its journey to completion was anything but simple. It took six years of planning, drafting, revising, and negotiating with vendors around the world to get the blueprints ready. And in just 21 intense days last November, a rotating team of architects, engineers, researchers, and fabricators converged in Corning, New York, each playing a crucial role in bringing the structure to life.

In the summer of 2017, a year into his tenure at Penn, Akbarzadeh began the initial conceptualization and design of what would eventually become the Glass Bridge. “At the beginning, it was just an idea about using thin sheets of glass to build a super-efficient structure,” Akbarzadeh says. “But it very quickly grew into a larger study of structural resilience.”

The bridge and its prototype, he explains, draw on millennia-old engineering and architectural principles, particularly those associated with funicular design—structures that follow the natural flow of forces acting through them, primarily harnessing compression to achieve stability and strength. The use of these principles exists as early as 4000 BCE, when the Mesopotamians constructed arches and domes, and later with the Romans through aqueducts, bridges, and monumental structures like the Basilica of Maxentius that were designed to balance forces through arches and vaults.

However, while ancient builders relied on empirical intuition, the underlying mechanics remained largely unformalized until the 17th century. It was Robert Hooke, an English physicist and mathematician, who articulated a foundational principle of structural design in 1675: “As hangs the flexible line, so but inverted will stand the rigid arch.” Hooke’s observation, though elegantly simple, revealed a profound truth: an inverted version of a hanging chain naturally follows the perfect compression curve of an arch under uniform load.

“If you have the right form,” Akbarzadeh explains, “you can reduce the material and work with efficient and elegant forms.”

Hooke’s insights informed the work of Akbarzadeh’s major influences, James Clerk Maxwell and William John Macquorn Rankine. These 19th-century engineers, he says, “formalized the mathematical foundations of graphical statics, providing methods for visualizing and analyzing the internal forces within structures.”

Akbarzadeh extended the methods of graphic statics from two dimensions to three, expanding Rankine’s 1864 proposition, since his Ph.D. thesis in 2012, at Penn since 2017, and outlined in his new book, “Polyhedral Graphic Statics.”

Akbarzadeh and his team designed the bridge’s geometry to channel forces along ideal compression paths. Every glass unit, joint, and angle was optimized so that the bridge’s arch would carry the load primarily through compression rather than bending forces—a method as ancient as the Sumerian U arches, now realized through cutting-edge computation and fabrication technologies.

Read the full story at Penn Today.


This work was supported by a National Science Foundation CAREER Award (NSF CAREER-1944691 CMMI) and by Lori Kanter Tritsch, a Master of Architecture alum who serves on the Weitzman School’s Board of Advisors.