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The Royal Canal, linking Dublin to the mighty River Shannon was finally closed to navigation in 1961, and since
then its route has been blocked by ad hoc access dams, roads and silt.
In 2007, Waterways Ireland commissioned
Finns to unblock and rebuild the last of the Victorian-era locks at
Clondra, Co Longford, as part of its multi-million Euro renovation of
the canal network and proposed reopening in 2009.
Waterways Ireland's senior engineers
wanted to try a new approach to rebuilding the collapsed lock chamber
and specified the use of the original lime mortars and the rebuilding in
original Ashlar masonry limestone.
Finns delivered the project to schedule
and to budget and were able to blend our traditional craft skills with
more modern methodologies such as low pressure grouting to seal the lock
from future leakage.
Working behind a temporary dam holding
back millions of gallons of water in a 5m deep unstable and partially
collapsed lock posed significant hazards, but we were able to conduct
the project with no accidents or incidents thanks to carefully
considered risk assessments and safe systems of work.
The six month project saw Finns deploy
our full range of skills including:
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Design & Build Scaffolding access
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Ashlar limestone stone masonry
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Lime pointing and grouting
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Temporary Dam Construction
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Low-pressure grouting
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Specialist stone repair
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Rock drilling
All the above was done in the absence of
any original construction drawings and it is testament to the
craftsmanship of the Finns stonemasons that they were able to rebuild
exactly to the 1817 original, a rubble core Ashlar faced lock. |
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Collapsed Lock Chamber
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Neglected for more than 40 years, the
final Lock No 45 chamber on the Royal Canal linking Dublin to the
Shannon was in a parlous state and posed significant working risks.
A Finns-designed box scaffold both braced
the collapsed Ashlar masonry and multi-decked to allow access to the
work face while ad hoc access dams were removed and replaced with an
orthodox puddle clay dam by Finns.
With no drawings of any kind our masons
set out to rebuild the lock chamber using reclaimed stone, repairing and
redowelling original stone to restore the Ashlar facing without the need
for modern imported stone.
Counterfort walling and embankments had
collapsed or simply eroded so Finns used modern pressure grouting
techniques to stabilise the surrounding structures and soil substrate
around the lock chamber reducing leakage from the canal system simultaneously.
The project yielded some fascinating discoveries.
Our team recognised the remains of a Victorian lime kiln built into the
original structure adding a valuable record to working practices of the
era and work was halted when further Victorian artifacts were found
during excavation.
Waterways Ireland's Heritage Officer
officer was informed and the finds duly catalogued and lodged with
Longford County Council museum service. |
