BBC Home

Explore the BBC

Front Page

Life | The Universe | Everything | Advanced Search
 
Front PageReadTalkContributeHelp!FeedbackWho is Online

Click here to complete your registration.

 
2. The Universe / The Earth / Europe / Norway
2. The Universe / The Earth / Europe / Turkey
3. Everything / Maths, Science & Technology / Engineering

Leonardo's Bridge

Leonardo da Vinci designed a bridge for the Sultan of Istanbul. It was never built, but recent studies have shown that the bridge was an amazing piece of engineering design, so a Norwegian company has built a smaller version from the same plans in Norway and it is a sight to behold!

The Golden Horn

Istanbul, the biggest city in Turkey1, is divided into three separate regions by the sea. Running from south west to north east is the Bosporus, a kilometre-wide channel of the sea which is traditionally the divide between the continents of Europe and Asia. Up until the last century, the city was entirely on the western (European) side of this channel of water.

More interesting is the deep water inlet known as the Golden Horn. This runs in a westerly direction from the west side of the Bosporus. It divides the old city of Istanbul into two. To the south of the inlet is the original city founded by the Greeks and later expanded by the Romans. Known as both Byzantium and Constantinople, it was the possibly the greatest city in the world for nearly a thousand years. To the north of the Golden Horn is the suburb known now as Beyoglu but for most of its existence as Galata. This started out as a small village but gradually grew to be a sizable suburb of the city.

There was a narrow bridge across the inlet in the 12th century, somewhat to the west of the city, but it was destroyed during the Crusader siege of 1204 and was never rebuilt. By the time the Ottomans captured Istanbul in 1453 and made it their capital, the district of Galata was quite big, but was cut off from the rest of Istanbul by the Golden Horn. The inlet itself is only 300 metres wide, but is very deep, making it difficult to bridge.

The Design

In 1502, the Sultan Bajazet II decided he needed a bridge. He commissioned none other than Leonardo da Vinci himself to design the bridge. Leonardo's design was strange in the extreme: a stone bridge in a single graceful arch, thin at the centre and widening both horizontally and vertically at the ends to join onto the land in a series of curves; the design is organic-looking and resembles the roots of a tree. The whole style of the bridge is a triumph of minimalism, totally unlike the baroque masterpieces popular in Europe at the time.

Some details of Leonardo's design:

  • Width at centre: 24m
  • Height above sea at centre: 40m
  • Span: 240m
  • Total bridge length: 360m

We don't know the Sultan's reaction to Leonardo's plans, but the bridge was never built. The inlet remained unbridged until the 19th Century when an ugly and cumbersome floating bridge was built. This was later replaced by the present Galata Bridge.

The Bridge of Aas

The designs for Leonardo's bridge were forgotten about. They were included in an exhibition on the work of Leonardo, but nobody really looked at them until 1996, when Norwegian artist and architect Vebjørn Sand saw the plans and was bowled over by them. He analysed them using modern civil engineering knowledge and discovered that the bridge didn't just look good, it was also a miracle of clever design. The extremely narrow centre of the bridge reduces the load on the sides to such an extent that the weight is not too great, and a single 240m span of stone can cross the entire inlet; nobody has ever built a stone bridge of this size to this day, but it appears that Leonardo's Bridge would have been viable.

But whether it would have remained standing for long is not clear - Istanbul is an earthquake zone, and Leonardo may not have taken this into account in his design.

Sand was so impressed with the bridge that he was determined to build a copy of it. He approached the Norwegian National Roads Authority. They were interested and eventually found a suitable site, in the village of Ås (sometimes written as Aas), where a footbridge over a motorway was needed. The road is the E18, the main motorway from Oslo to Stockholm, so the bridge is seen by many travellers every day. Sand worked with the road engineers and Leonardo's plans, scaling them down to one third size to produce the world's first Leonardo-designed bridge. In keeping with Norway's reputation as a forested country, wood was used rather than stone. The bridge was opened at the end of 2001. You can see it today if you go to Oleghus in Norway, as well as at the bridge's official website.


1 According to the 2005 UN Population Division, Istanbul has around 9,760,000 inhabitants. The city itself covers an area of 769 sq miles, while the metropolitan area covers 2204 sq miles.

Discuss this Entry  People have been talking about this Guide Entry. Here are the most recent Conversations:

Never built but constructed in Norway
(Last Posting: Jun 13, 2007)

Fascinating, but I wonder...
(Last Posting: Jun 13, 2007)




Add your Opinion!

There are tens of thousands of h2g2 Guide Entries, written by our Researchers. If you want to be able to add your own opinions to the Guide, simply become a member as an h2g2 Researcher. Tell me More!

 
Entry Data
Entry ID: A22548369 (Edited)

Written and Researched by:
U151503 - Gnomon - Future Guide Editor - towels at the ready

Edited by:
SchrEck Inc.


Date: 13   June   2007


Text only
Like this page?
Send it to a friend


Referenced Guide Entries
Earthquakes
A Quick Guide to Norway
Renaissance Art
Istanbul, Turkey
Byzantium: Overview


Related BBC Pages
Leonardo da Vinci - BBC History


Referenced Sites
The Leonardo Project Bridge
Leonardo Bridge Project

Please note that the BBC is not responsible for the content of any external sites listed.

Most of the content on this site is created by h2g2's Researchers, who are members of the public. The views expressed are theirs and unless specifically stated are not those of the BBC. The BBC is not responsible for the content of any external sites referenced. In the event that you consider anything on this page to be in breach of the site's House Rules, please click here to alert our Moderation Team. For any other comments, please start a Conversation below.
 


Front PageReadTalkContributeHelp!FeedbackWho is Online

Most of the content on h2g2 is created by h2g2's Researchers, who are members of the public. The views expressed are theirs and unless specifically stated are not those of the BBC. The BBC is not responsible for the content of any external sites referenced. In the event that you consider anything on this page to be in breach of the site's House Rules, please click here. For any other comments, please start a Conversation above.


About the BBC | Help | Terms of Use | Privacy & Cookies Policy