Leonardo da Vinci's bridge performance evaluation

A bridge designed by Leonardo da Vinci but was never constructed is now being tested by engineers at the Massachusetts Institute of Technology (MIT).

Back in 1502, Leonardo da Vinci designed a 280-meter structure that would be the longest bridge in the world at that time. The endeavor followed a proposal issued by Sultan Bayezid II, Sultan of the Ottoman Empire from 1481 to 1512, who wished to connect Istanbul with a nearby city, Galata, separated by a waterway, called Golden Horn.

Leonardo da Vinci came up with an innovative design but it was not qualified and, therefore, it has never been implemented. Now, researchers at MIT are investigating on the performance of da Vinci's bridge.

The team constructed a scale model the evaluates the structure's integrity and its ability to bear loads and withstand soil's potential subsidence. They used data concerning the geological profile of the area, the materials available and the construction techniques utilized at that time.

During the 16^th century, common bridges erected used piers to support the weight of the structure. However, da Vinci designed a long, single-arch bridge that would reach a high elevation allowing the ships to pass by. "It's incredibly ambitious. It was about 10 times longer than typical bridges of that time," Karly Bast, a graduate student at MIT, stated. Da Vinci also knew that the area was earthquake-prone and added supportive abutments on the arch's ends to resist lateral oscillations. 

The most likely scenario is that stone would have been used for the construction of the bridge at that time. Scientists could not detect any construction details but probably stone blocks would have been assembled together without using any binder. The researchers created an 81-centimeters scale model using 126 3D-printed blocks held together by a scaffolding (a technique used since Roman times). When the scaffolding was removed, they had to insert the final piece of the structure at the top of the arch.  “When we put it in, we had to squeeze it in. That was the critical moment when we first put the bridge together. I had a lot of doubts. When I put the keystone in, I thought, ‘this is going to work.’ And after that, we took the scaffolding out, and it stood up,” Bast, added.

Leonardo da Vinci's creation was successful. According to the findings, the bridge was stable and was capable of withstanding horizontal displacements produced by seismic shocks. It is remarkable how da Vinci was able to understand the mechanics of a structure at that time. “Was this sketch just freehanded, something he did in 50 seconds or is it something he really sat down and thought deeply about? It’s difficult to know. But proving the effectiveness of the design suggests that Leonardo really did work it out carefully and thoughtfully. He knew how the physical world works," Bast concludes.