Building Da Vinci's Forgottten Bridge

When Sultan Bayezid II of the Ottoman Empire requested proposals for a bridge connecting capital city Constantinople (now Istanbul, Turkey) with the neighbouring city, Galata (Karaköy, Turkey) at the turn of the 16th century, famed inventor Leonardo da Vinci was eager to win the contract.

- David Grossman

He didn’t get the job, but more than 500 years later, a team of researchers at the Massachusetts Institute of Technology suggests that maybe he should have. Karly Bast, who graduated from MIT in 2019 and is now at Buro Happold Engineering, worked alongside structural engineer and MIT professor John Ochsendorf and undergraduate Michelle Xie to analyse Leonardo’s sketches and letters (pulled from Manuscript L, a small Codex stored in the Institut de France in Paris). They also researched historically accurate materials and construction methods to prove that Leonardo’s unique bridge design would have held up.

The team created a 1:500 scale model of the bridge (making it about one metre long), which the inventor described in a letter to the Sultan as ‘a masonry bridge as high as a building, [so] even tall ships will be able to sail under it’. Leonardo’s concept was for a flattened bridge with a long arch – a radically different style from anything that had previously been constructed. At the time, many bridges featured a semicircular arch, often half as tall as the span of the bridge, instead of a sweeping parabolic arch.

Leonardo’s bridge would have spanned roughly 280 metres (or 918 feet) – neither measurement had been invented yet, so he used a unit of measurement called braccia. It would have been about 10 times longer than typical bridges of that period in order to span the river, Bast says.