On Friday 5 August, the Mizen Head Footbridge was officially opened by Minister for Transport, Tourism & Sport, Leo Varadker T.D. The opening marked the successful completion of a very complex engineering project for RPS, our client Cork County Council and the contractor Carillion Irishenco.
Mizen Head Footbridge is located at the south westerly tip of Ireland. Spanning 50m across a dramatic sea gorge, it leads to the Mizen Head Lighthouse owned by the Commissioners of Irish Lights. The original structure was built in 1909 and was considered to be the longest reinforced concrete bridge of its type in Europe at the time.
After 100 years of service, the iconic bridge has been demolished and faithfully reconstructed to its original form. The complex project was delivered on time and within budget to the satisfaction of the funding authorities – Fáilte Ireland, Cork County Council and the Commissioners of Irish Lights. “102 years later, the project team has successfully delivered a new, replica reinforced concrete structure, following careful removal of the original structure” says Kieran Ruane, Project Manager, RPS “The successful completion of the project has preserved a landmark structure on the coast of Ireland for future generations to enjoy.”
Mizen Head is a site characterised by dramatic cliffs with steep, narrow footpaths and spectacular views over the Atlantic Ocean. The bridge is a twin arch structure, which supports a pedestrian bridge deck. The original reinforced concrete bridge displayed many of the defects associated with concrete structures in a marine environment.
The landmark bridge project provided significant challenges to the design and construction teams. Access to the site was extremely difficult, via a steeply inclined footway, less than 1 metre wide. The bridge was located in an environmentally sensitive marine location and was subject to severe weather due to the exposed, coastal nature of the site. The bridge had a clear span of 50m and the soffit of the deck was located 45m above a sea gorge.
“The key challenge was to design a scheme that would allow safe demolition of the existing bridge and safe construction of a new bridge, with minimal disruption to the local environment” noted Kieran Ruane “The bridge is a well known and loved landmark in Ireland and the project drew considerable interest from the general public during construction.”
The new bridge is a structure of identical nature and form to the original structure, though marginally wider (700mm). The innovative concept allowed for the initial construction of new structural members using the old members for support. The scheme progressed as an integrated series of demolition and construction of individual structural elements. The concept garnered significant support from heritage professionals and other interested parties, as it preserved the form of the original structure. The structure comprises an intricate framework of elements and the details of these elements were faithfully recreated from the original structure.
RPS designed additional tourism facilities during construction of the bridge. These include walkways and viewing platforms, from higher viewing levels above the bridge, to enhance the visitor experience.