failure of tay bridge
TRANSCRIPT
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 1/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 2/25
TECHNICAL INFORMATION • The original Tay Rail Bridge was
constructed in the 19th century by railway engineer Thomas Bouch at Dundee.
• Thomas Bouch completed the bridge in
February of 1878
• The Tay bridge was nearly two miles long,at the time was the longest bridge in the
world.
• Tay bridge was supported on cast iron columnsstrengthened with wrought iron struts and ties.
It carried a single rail track.
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 3/25
• The bridge was 85 spans wide with 13
navigation spans which were higher and largerthan the others.
• Of the 13 navigation spans, eleven were 245
feet and two were 227 feet.
• 72 of these spans were supported on deckspans,
the remaining 13 navigation spans were through
girders. These " high gir ders" were 27 feet high
with an 88 ft clearance above the high water
mark.
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 4/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 5/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 6/25
However, as there were no codes of practice at the
time, structural design was often based onexperience rather than accurate calculation.
Therefore " the br idge was bui l t with only two things in mind - Speed of construction and cost. This meant
that aspects such as safety and durabil i ty were not
considered as carefully." .
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 7/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 8/25
The High Girders section were mounted with the
box between the piers containing the track within to
provide clearance for vessels on the Tay.
A combination of the high pressure of wind on that
section containing the train and the poor quality of
the design and materials used were blamed in a
enquiry.
REASONS FOR FAILURE
At 7:15 p.m. on the stormy night of 28 December 1879, the
central spans of the Tay bridge collapsed into the Firth of Tay
at Dundee. A train including six carriages and 75 people fell
into the cold water below. At the time, a gale estimated at
force 10 to 11 was blowing down the Tay estuary at right
angles to the bridge.
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 9/25
Lateral oscillations were induced in the highgirders section of the bridge by trains passing
over a slight misalignment in the track.
The amplitude of these oscillations grew with
time, because joints holding the bridge together
were defective, and this in turn resulted in
fatigue cracks being induced in the cast iron
lugs, which reached criticality on the night of
Some of the Iron from this foundry was very poor quality.
Also during its construction one high girder on a barge
was lost to storms for a night and another was droppedonto the sea-bed whilst being lifted into place. These
sections were still used.
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 10/25
Figure shows the northern end of thecollapsed section, the two rails wrenched
towards the east in the direction of fall.
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 11/25
This view demonstrates the collapse duringthe great storm of 1879, which removed 13
spans of 245 feet each from thesuperstructure of the Tay Rail Bridge.
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 12/25
The stresses imposed by the falling columns have wrenchedtwo substantial courses of masonry from the underlying pier.Flanged joints on the columns have failed and the decking of the bridge, together with other parts of the structure, hasdisappeared into the icy waters of the Tay.
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 13/25
The inherent weaknesses of the flanged joints areclearly illustrated by the clean break above thesecond line of columns on the pier in the middledistance.
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 14/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 15/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 16/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 17/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 18/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 19/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 20/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 21/25
Collapse Mechanism
1. When the train reached the high girders there was a
particularly strong gust.2. This increased the overturning force enough to
cause the windward column base to lift.
3. The diagonal ties begin to fail in a brittle mode
starting at the second level and possibly above (but
not at the bottom level).
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 22/25
4.This weakens the second level causing failure of
the bolted connections in the columns at that level.Simultaneously the bracing failure extends upwards.
The column support on the leeward side becomes
ineffective. That side starts to drop and the whole pier
starts to rotate about the second level.
5.As it falls there is a kickback on the first level
causing it to be demolished but retaining most of the
wreckage on top of the foundation.
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 23/25
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 24/25
TAY BRIDGE TODAY
7/27/2019 Failure of Tay Bridge
http://slidepdf.com/reader/full/failure-of-tay-bridge 25/25