Tyne Bridge vs Sydney Harbour Bridge

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The Tyne Bridge is not a copy of the Sydney Harbour Bridge (or vice versa). The North-East icon is as unique as the big river it spans. But what makes the Tyne Bridge one-of-a-kind, and which far-away bridge actually inspired its design? A thread: 🧵

Although they share similar features, neither the Tyne Bridge nor the Sydney Harbour Bridge is a copy of the other. They were built concurrently. The larger Sydney was first to be started, and the smaller Tyne was first to be completed. Tyne: Sydney:

Both the Tyne Bridge and the Sydney Harbour Bridge were built by contractors Dorman Long and designed by engineer Ralph Freeman. Freeman's designs for both were inspired by an entirely different bridge—the Hell Gate Bridge in New York:

The Hell Gate Bridge sits over a tidal strait of the East River in New York. It was built between 1912 and 1916 by engineer Gustav Lindenthal. Ralph Freeman visited New York during construction and referred to Lindenthal's plans when designing the Sydney and Tyne Bridges.

The Tyne Bridge opened in 1928 and has an arch span of 531ft. The Sydney Harbour Bridge opened in 1932 and is about three times bigger, with an arch span of 1650ft. But this comparison diagram also shows the Tyne Bridge's unique design difference...

Although the designs look similar, the Tyne Bridge is unique because it is a crescent arch bridge. Its arch ribs form a crescent shape. The Sydney (and Hell Gate) are spandrel arch bridges. But keep reading for a surprise...

I found Gustav Lindenthal's 2 different designs for the Hell Gate Bridge, from 1905. He used the bottom Spandrel Braced Arch Design. A similar design was used in Sydney. He didn't use the top Crescent Arch Design, but it clearly inspired the design of the Tyne Bridge:

The Tyne Bridge's unique crescent arch is a pleasing natural shape, like the waxing or waning moon or a banana! Experts suggest this is why the Tyne Bridge has "a most beautiful design" compared to the "less elegant" Sydney Harbour Bridge. 🌙 🍌

There's lots more about the Tyne Bridge and how it was designed and built in my new book, which is out now! You can get more information and links to buy here: tynebridgebook.com/