Some 500 years after his death, Leonardo da Vinci is still well-known as a Renaissance master artist and prolific inventor. MIT engineers have also just proven his engineering prowess in bridge design.
In 1502, da Vinci submitted an innovative bridge design for a contest to connect Istanbul and Galata for Sultan Bayezid II. His design was rejected.
Considering da Vinci's sketch for the project, MIT recent graduate student Karly Bast, working with professor of architecture and of civil and environmental engineering John Ochsendorf and undergraduate Michelle Xie, analyzed documents, along with the possible materials and construction methods that were available at the time, and the geological conditions at the proposed site, which was a river estuary called the Golden Horn. The MIT team built a detailed scale model.
They presented their results in Barcelona this week at the conference of the International Association for Shell and Spatial Structures. An episode of the PBS program NOVA will cover their findings on Nov. 13.
Leonardo's bridge concept was dramatically different from design of the period—it showed a flattened arch that would be tall enough to allow a sailboat to pass underneath with its mast in place, as illustrated in his sketch for the Sultan, but that would cross the wide span with a single enormous arch.
The bridge would have been about 280 meters long, making it the longest span in the world at that time, had it been built. "It's incredibly ambitious," Bast says. "It was about 10 times longer than typical bridges of that time."
Bast and the team analyzed the materials available at the time and concluded that the bridge could only have been made of stone, in a complex pattern of blocks.
A pedestrian bridge in Norway is one example of how da Vinci's design has inspired in the past, but the modern materials used for construction never proved the feasibility of Leonardo's engineering.
"It's the power of geometry" that makes it work, Bast says. "He knew how the physical world works."
While modern bridge designers have today's materials and methods to produce even lighter and stronger bridges than were possible in the Renaissance, the MIT work on Leonardo's design further proves the brilliance of one of the world's greatest innovators.
It also demonstrates, Bast says, that "you don't necessarily need fancy technology to come up with the best ideas."