Dublin Diving Bell to link city’s maritime past and present
07 April 2015
The Dublin Diving Bell has been a feature on Sir John Rogerson’s Quay in Dublin city since the 1870s – a physical acknowledgement of Dublin’s maritime and construction heritage. Many have passed by the bell-shaped metal structure and wondered what it was. Some have mistaken it for a piece of modern art, while others have passed it off as scrap metal. It is in fact an ingenious feat of Irish engineering that was essential to the building of Dublin’s quay walls.
The refurbishment of the Diving Bell is now taking place and is expected to be completed by June 2015. Weslin Construction, along with the Dublin Port Company, have embarked on a project that will shed light on this important artefact and transform the 13-metre tall, 90-tonne structure into a new interpretative exhibition that explains its origin and history.
Weslin Construction has a proven track record in one-off unique projects that are required to fit in well with their surrounding landscape. These include the refurbishment of the 152m-long Bull Island Bridge in Clontarf and the installation of four steel-structured rain screen umbrellas within Temple Bar’s Meeting House Square, a cultural area within the heart of Dublin’s city centre.
Aidan Boyle, managing director of Weslin, explained that it was the unusual nature of the Diving Bell refurbishment that originally attracted the company to tender for the project. “As a company, we enjoyed the unusual aspects of the umbrellas in Temple Bar and the Wooden Bridge in Clontarf,” he said. “The Dublin Diving Bell project is similar in some senses and it has been going particularly well so far. A camera has also been installed that will record the project as a time-lapse video, so we’re looking forward to watching the development back after completion.”
History of the Diving Bell
The Diving Bell was designed by port engineer Bindon Blood Stoney (1828-1907) and built by Grendon and Co, Drogheda. A ground-breaking piece of engineering innovation at the time, it was delivered to Dublin Port in 1866, entered service in 1871 and was used in the building of the port’s quay walls until 1958.
Stoney was a prodigious engineer and among his achievements were the building of the Boyne Viaduct in Drogheda, the construction of O’Connell Bridge and the building of many of the deep-water quays along the River Liffey, including Sir John Rogerson’s Quay and North Wall Quay Extension. Appointed in 1862 as the Dublin Ballast Board’s chief engineer, Stoney decided to use a novel method of underwater construction.
Massive concrete blocks of 350 tonnes were made on the quayside. The lower section of the Diving Bell was hollow and bottomless, providing just enough room for six men to work at a time. Once this was lowered into position on the riverbed, the crew entered through an access funnel from the surface and compressed air was fed in from an adjacent barge. The men inside the bell worked on the river bed exposed at their feet to level it, excavating the site where the massive concrete blocks would later go. All the excavated soil was stashed in trays hanging inside the bell, and brought up when the bell was lifted.
The works now taking place involve the elevation of the existing Diving Bell through the provision of a new supporting steel structure. The bell will be elevated onto a two-metre steel structure, creating a ramped public access route underneath. Boyle explained that this process will require the use of a 350 tonne crane.
“In its entirety, the Diving Bell weighs 90 tonnes. It’s made of cast iron and is fitted with steel counterweights,” he said. “It has a funnel that’s about 15 metres high and the base is approximately six metres squared. To move it and place it back on its stand is a fairly major piece of work and that’s why the 350-tonne crane is required.”
The new structure will contain an information display centre, inclusive of graphics and the shallow water feature. The water feature will offer visitors the impression of how it may have felt working within the Diving Bell. New perforated stainless-steel screening will be installed in the vicinity of the bell and specialist energy-efficient LED lighting will provide a visual focal point on the quay at night. A series of interpretative panels will also be installed, explaining the historical, social and engineering significance of the Diving Bell.
“The bell was designed in the 1850s and it’s protected by a preservation order, although we do intend to move it slightly from where it is now. A brand new base is being constructed that will include a water feature underneath. This will offer visitors the feeling of working inside the bell. The water will flow in and out underneath the Diving Bell floor, reflecting the tide of the River Liffey,” said Boyle.
The project, the first in Dublin Port’s plan to create a ‘distributed museum’ of attractions across the Dublin Docklands and into the port to preserve the city’s industrial heritage and history, has been designed with the expertise of architect Sean O’Laoire, the sculptor Vivienne Roche, Tom Cosgrave, professor of engineering at the University of Limerick and Mary Mulvihill of Ingenious Ireland.
“The Diving Bell is a remarkable feat of Irish engineering and Dublin Port Company is proud to invest in its transformation and bring the history of this magnificent structure to life along the Liffey,” said Eamonn O’Reilly, chief executive, Dublin Port Company. “True to the commitment in our Dublin Port Masterplan, we’re working to better integrate Dublin Port and the city. Developing the Diving Bell is the first step in our plan to create a distributed museum of port and industrial heritage attractions across the Dublin Docklands and into the port.
“We’re confident that the Diving Bell will give Dubliners and visitors to the city a true sense of Dublin as a port city with a wealth of industrial heritage to discover,” O’Reilly concluded.http://www.engineersjournal.ie/2015/04/07/dublin-diving-bell-renovation/http://www.engineersjournal.ie/wp-content/uploads/2015/03/image-1-1024x683.jpghttp://www.engineersjournal.ie/wp-content/uploads/2015/03/image-1-300x300.jpgMechDublin