18 NSC
April 18
Spanning the River Severn in
Shropshire, Iron Bridge has
become an iconic and universally
recognised symbol of the industrial
revolution. Opened in 1781, it pioneered the
path to using cast iron on a large scale and
consequently the construction industry was
never the same again.
Having stood for more than 230 years,
the UK’s best-known industrial monument
is today suffering in its old age. In fact, there
are numerous cracks in the structure, due
to stresses in the ironwork dating from the
original construction, ground movement over
the centuries, and an earthquake that struck
in the late 19th Century.
To remedy these ailments and preserve
the bridge for future generations, English
Heritage, with the aid of steelwork contractor:
Taziker Industrial, has embarked on a
conservation programme. This work will
see the different elements of the bridge - the
iron radials and braces holding the structure
together, the deck plates and wedges, the main
iron arch, and the stone abutments on either
side of the Severn – examined and repaired.
Taziker Industrial Project Manager
Duncan Warburton explains: “This is a
conservation job and not a refurbishment,
and so as much of the original materials have
to be retained in an unaltered condition.
All of our work must not remove, alter or
permanently bond, cross or link to any
original part.
“Consequently, all of the work must be
reversible and removable without affecting
the condition of the original material now or
in the future.”
Unusually for a steelwork contractor,
Taziker is not only working with the original
cast iron elements, all new metal added to
the bridge must also be iron. The company
is employing a specialist ironwork firm to
fabricate and supply new material for this
project.
All of the new ironwork is bespoke and
each new piece is different and unique. Many
parts of the main arch structure have cracks,
these are being repaired by adding a new iron
brace that is bolted to the existing iron, and
then wraps around it to keep it in place. In
this way, no original iron member is removed
even if it is cracked.
Other repairs are being done to the bridge’s
deck as ongoing corrosion of the packing
pieces between the plates and supporting
beams is causing the deck to slowly lift. New
iron packing pieces are being fabricated and
will be installed, while broken deck plates will
be strengthened with new ironwork.
In order to carry out this work, Taziker
had to erect an access scaffold to the bridge.
This has a fixed sheeted roof and sides,
shrouding most of the structure from view.
Within this encapsulated space, the initial
works began with the entire ironwork being
cleaned and the rust build-up removed by
pressure grit blasting.
English Heritage made a commitment
to maintain public access between the
communities on either side of the bridge
throughout the works, so Taziker has
divided the bridge deck in half, working
on the downstream half first and allowing
pedestrians to use the upstream half. Once
the first half of the deck is complete, the
procedure will be reversed.
On the underside of the bridge, the main
works continue unhindered by the need
to give public access. However, a public
walkway is being erected on the upstream
Heritage
Spanning the centuries
English Heritage is undertaking a major conservation
programme to repair and conserve the world’s first single span
cast iron arch bridge.
FACT FILE
Iron Bridge
conservation
Main client:
English Heritage
Main contractor:
Taziker Industrial
20
/Bridges
/Fabrication
/Bridges#Arch_bridges
/Corrosion_of_structural_steel
/Fabrication
/Construction#Steel_erection
