Project Feature: Donnybrook landmark reopened thanks to Clonmel Enterprises

CIF Jobs 06/03/2017 Latest News

Donnybrook’s beloved Beaver Row Footbridge returned to use in 2015 thanks to an intricate job by Clonmel Enterprises.

The footbridge, which connects Beaver Row to Brookvale Road in Donnybrook, Dublin was constructed circa 1880 and is considered a landmark of Donnybrook.

“The footbridge, which was a local community access to Donnybrook church was closed to the public for a number of years due to safety concerns,” says Anne Kinsella Engineering Manager with Clonmel Enterprises. “It has significant architectural heritage value and is a protected structure and as such, all rehabilitation was required to be carried out at a prequalified specialist ironwork repair facility.”

Following an assessment of the bridge significant corrosion was identified.

“It appeared that the concrete deck, which had been cast sometime in the 80’s had caused a significant amount of the deterioration by trapping moisture against the iron elements,” Anne Kinsella explains. “The solution was an integration between old and new materials. The original deck, which was initially timber and later concrete, was replaced with a fabricated steel deck waterproofed and texture surfaced, which acted as the main structural element. This was not visible in the final solution and all other existing cast iron elements were to be restored with cast iron.”

In order to carry out the restoration, the entire footbridge was transported to a foundry. However, this process presented some significant challenges with both Safety and Environmental risks.

“To minimise the weight of the lift, the existing concrete deck was removed in-situ over the river with associated environmental risks of contamination to the River Dodder,” Anne explains. “In order to carry out the work to remove the deck and lift the bridge, the River was accessed. While the river flowed at a depth of approx. 400mm, the Dodder River is very prone to flash flood and any temporary works was designed with this in mind. The replacement central pier was founded on rock in the centre of the river approx. 2m below bed level on an in-situ concrete base again with associated environmental risks.”

Bushy Park Ironworks, Artist Blacksmiths and Metal Workers carried out the restoration works. To maintain the historical heritage of the structure, corroded sections were replaced with comparable cast iron elements salvaged from original Dublin railings and Naval chains from the UK.

The materials were worked using original Blacksmiths methods to produce the replacement sections for the trusses, including in excess of 500 hand-forged rivets.

“Our Project Management approach matched a traditional metal work skill as an innovative and complex solution in an environmental challenging location using sustainable methods to safely provide a quality assured product with direct benefits to the local community,” Anne Kinsella says. “The success of this project was based on the management of the specialized, multi-disciplinary teams essential to the restoration of this historic, protected structure. Despite being a small project the restoration and refurbishment of Beaver Row Footbridge included many aspects of our industry, including temporary works, demolition, refurbishment and reconstruction works an environmentally sensitive urban location. A key element to our successful delivery of this project was our understanding and appreciation of the importance of the history and heritage of the bridge, from the locals who have used it for generations as well as the wider Dublin community and City Council.”

“One of the main challenges we faced on this project was the procurement of a suitable specialist forge,” Anne adds. “The art of wrought iron refurbishment in a traditional forge is almost forgotten and it was essential to the success of the project to combine the skills of the artisan blacksmith with the requirements of modern steel design, certification and construction methods. The skills, knowledge and commitment of our site team and the many specialists who protected, removed, restored and reinstalled a 140 year old protected structure, have given us an attractive functional new bridge to be proud of for many generations.”

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