Technical Advancements:
The Cost of Progress
Transport by Land: Tay Bridge, 1879
Tay Bridge, 1879
Lesson Objectives:
• Investigate the technological advancement in
railway bridge construction
• Realise that sometimes there is a heavy price
to pay for advancements in technology and
that lessons must be learnt
Tay Bridge, 1879
• Listen to this poem and write in the back of
your books any important facts about the
disaster.
Tay Bridge, 1879
Task: Listen to the poem and try and jot down important facts about the Tay Bridge
Disaster, 1879.
Note – When he says 90 lives were lost, it is now estimated to have been around 75.
Tay Bridge 1879
• In the 19th century, the people of Britain took pride in their
technological achievements.
• Britain’s railway system led the world. In 1879, the
Victorian’s confidence in British technology was further
boosted by the opening of a bridge across the River Tay in
Scotland.
Tay Bridge 1879
• At 3km in length, it was the
world’s longest bridge.
• Queen Victoria herself travelled
across the bridge
• knighted its
designer, Thomas
Bouch, on the spot!
1822 - 1880
Tay Bridge 1879
• The Tay Bridge was a remarkable
engineering achievement – or so it
seemed.
Tay Bridge 1879
• The Tay Bridge disaster occurred
during a violent storm on 28th
December 1879 when the first Tay
Rail Bridge collapsed while a train
was passing over it from Wormit to
Dundee. The train crashed into the
river killing all aboard.
• To this day, the Tay Bridge disaster
remains the worst railway disaster
in British history.
Tay Bridge 1879
Activity:
• Watch the short documentary on the
Tay Bridge disaster.
• What do these images and documentary
suggest about the horror of the tragedy?
•
http://www.youtube.com/watch?v=Zg4cG1CZHjI
Train
So what
happened?
Tay Bridge 1879
THEORY A
Bill Dow – Theory A: Train
“The rear carriages of the train derailed and ran into one of the cover
plates. The force of this impact would shatter the cast iron lugs –
leaving the bridge in a high wind without its proper structural
support”.
• The girder closest to Wormit, in the high girder section of the bridge,
had bent during the lifetime of the bridge. The girder had been
dropped during construction and bent.
• It was straightened out and reused, but over time it returned to the
bent shape.
• As a result, the rail tracks that ran over it developed a kink.
• This kink, combined with the high wind, may have been responsible
for the train derailment.
Wind
Train
So what
happened?
Tay Bridge 1879
THEORY B
Tony Martin – Theory B: Wind
“The disaster was investigated using modern computer analysis in
conjunction with a modern approach to wind loading. The bridge
was examined with and without the train to see what effect on the
performance of the pier structure. And a pier was analysed under
various load conditions with a view to proposing a mechanism for
collapse of the navigation piers”.
• The bridge was simply not strong enough to withstand the strength
of the wind that night.
• Although the presence of the train does affect structure, even
without the train the bridge would have fallen that night.
Wind
Train
So what
happened?
Bridge
Fatigue
Tay Bridge 1879
THEORY C
Peter Lewis – Theory C: Bridge Fatigue
“It was almost certainly the dynamic effects of the bridge itself
well before the disaster that brought the bridge down. These
led to gradual deterioration of the ironwork supporting the
high girders”.
• On the night of the storm, the bridge piers were no longer
capable of supporting the load of the train.
• Within that, fatigue and cracks in the bridge probably played
an important role.
Tay Bridge 1879
Task:
• Use the handout with the three possible theories for why
the Tay Bridge collapsed.
• You have to choose ONE theory from the three and write a
short answer on why you agree with that theory. Also try
and think about what you learnt from watching the
documentary.
• This activity forces you to make a decision and argue your
point.
Task: Tay Bridge 1879
I think theory ____(A,B or C) is the correct theory to help
explain why the Tay Bridge collapsed
because___________(include a couple of reasons/
explanations to support your argument)
Tay Bridge 1879
So, why do you think the Tay Bridge collapsed?
8L vote
What Lessons Were Learnt?
• All Bouch's bridges were examined and
reinforced or rebuilt.
What Lessons Were Learnt?
• Steel was approved by the Board of Trade for use in
bridges. Designs using cast iron columns were barred.
What Lessons Were Learnt?
• Regular and frequent inspections of bridges were
made during and following construction by Board of
Trade personnel.
What Lessons Were Learnt?
• A new Tay Bridge was built adjacent and parallel to
the original bridge reusing undamaged girders with
some modifications. The new bridge is over twice the
width to allow double rail tracks and greater lateral
stability. Piers in the centre were built from wrought
iron lattice work and steel. Original pier platforms
were retained to act as breakwaters for the new
bridge. New piers were tested by static loading for
settlement. The building was started in 1881 and
finished in 1885.
What Lessons Were Learnt?
• A Royal Commission on "Wind Pressure on Railway
Structures" was set up in 1881. Members of the
Commission included W H Barlow, G Stokes and W
Yolland. An extensive survey of wind speeds and
pressures using anemometers was undertaken at
numerous locations. Examples of overturned carriages
by wind action were examined. A maximum wind
pressure of 56 per square foot for design of bridges
and rules for applying this specification to bridges of
different construction were recommended.