Tuesday, October 10, 2017

Tay Rail Bridge

Satellite
The Tay Bridge is famous in bridge history. Finished in February 1878, it was the longest (nearly two miles) bridge in the world. But what made it famous is that at approximately 7:15pm on December 28, 1879, during a terrible storm, as a train with 75 passengers crossed the "high girders," they collapsed. No one survived. The piers of the replacement bridge were built next to the masonry piers of the original bridge to help combat tidal erosion. [Paul Johnson's comment on his posting] Because of the shadows from the bridge, it is hard to see the old piers. I chose this excerpt from the satellite image because two of the three piers stand out. The wrought iron girder spans did not collapse, and they were transferred to the present Tay Bridge where they are still in use today! [TayBridgeDisaster]
Denny Quartieri posted
Ladies and Gentlemen: First Tay Bridge. Unfortunatly it became a Creepy Halloween Tale but in Christmas' Eve.
Photo from National Library of Scotland
Tay Bridge from north
Photograph of the first Tay Bridge before its collapse.
Photo from National Library of Scotland
Tay Bridge from south after accident
Photograph of the first Tay Bridge after the collapse of a large section.

Photo from National Library of Scotland
Pier no. 8: looking west

Paul Johnson posted
Paul Johnson Bouch was pilloried at the enquiry. He relied upon the foremost authority in the country for wind pressure and wind speed figures. The expert hadn't even been to the Tay. Poor workmanship, design of the jibs and cotters of the columns by a sub contractor, employing someone who knew little of maintaining metal structures, missing rivets, and patched castings all had an effect. The carriages of the time were lightweight and it was not unknown for a carriage to be lifted from the rails in strong winds all contributed to the disaster. Bouch built a six times safety margin into the bridge based on the figures he was given. There is some conjecture that the train derailed and struck the bridge.
This is the first time I have read that Bouch consulted with a wind pressure expert. So it was really the expert that was at fault. Some descriptions I read implied that Bouch did not even consider the lateral force of winds. But he did consider it. However the figure he used, 10 lbsf/sq ft, was not large enough for the weather conditions in a river near the open seas. [TayBridgeDisaster]

Andrew Smith posted a couple of photos of a replacement.
1

2

Ian Lothian posted
The longest Railway Bridge in the UK is the Tay Bridge at just over two miles in length. This view is from the Fife side ( southern end ) looking north across the Tay Estuary to part of the City of Dundee. The Bridge is double track and was built to replace the first Tay Bridge which had collapsed in a violent storm on 28 December 1879 as a train was crossing; approx 75 people lost their lives. The piers of the first Bridge can be seen beside the present structure as the luxury Royal Scotsman Tour Train emerges from the High Girders on its way to Edinburgh at the end of a four night tour.


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AbandonedSpaces (Facebook source)


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