Spanning across a steep cliff section of the North Cornwall coast, a new footbridge at Tintagel has opened up exhilarating views of Tintagel Island, coastline and Atlantic seascape. Ramboll ground engineering team are designers for the foundations of the structure that has transformed the visitor experience at the historic Tintagel Castle site.
The prized historic site needed a 21st century link
Tintagel Castle’s thirteenth-century ruins are among the most spectacular historic sites in Britain set among precipices on a steep cliff section of the Cornish coast. It is one of English Heritage’s top five attractions within England, with around 200,000 visitors a year, up to three thousand per day in the peak summer season. Nearly a third of current visitors come from overseas and Tintagel’s profile is growing both nationally and internationally.
The existing approach was across a wooden bridge, slung low across the chasm separating the two surviving parts of the Castle. This bridge and linking paths suffered from congestion in the peak season, so a new bridge was needed. The new structure has not only transformed physical access and rationalised routes around the site, it has become a new attraction in its own right.
The design of the new footbridge was developed as part of a bridge design competition in 2015 that attracted 137 entrants including Ramboll UK. The judges were seeking an elegant, structurally daring bridge, which is sensitively balanced within the landscape.
In March 2016 Ney & Partners were announced winners of the competition. They appointed Ramboll as their designers for the foundations, based on ground engineering work previously completed at Tintagel:
- 2000 Stability review of the cliff faces detailed risks associated with the site’s development.
- 2013 Further study by Ramboll engineering geology and geotechnical specialists recommended geotechnical investigation works required for potential bridge solutions.
More than just a practical passage, the new bridge will be part of the experience
English Heritage commissioned a bridge from the mainland ward of the castle across to the island ward to provide practically step-free access to the castle and to accommodate increasing visitor numbers.
The bridge is formed of two cantilevers with a gap between the two. It spans approximately 72m between the mainland and island wards. The foundations are anchored pads with the anchors drilled into the fractured rock that form the steep cliffs.
Project constraints included landscape, archaeology and access
Tintagel Castle is not only a Scheduled Ancient Monument, it also lies within an Area of Outstanding Natural Beauty (AONB), Site of Special Scientific Interest (SSSI), and Special Area of Conservation (SAC). Scheduled Monument Consent was required for intrusive investigation works along with planning permission from the County Council, and due to environmental restrictions commencement of the investigation works were delayed due to Fulmars still nesting on the cliffs beyond their usual nesting period.
Access to both sides of the site is only possible on foot, therefore the use of a helicopter was required to lift plant and equipment into place.
While coins and artefacts found on the Island indicate some Roman activity, Tintagel is historically significant for its prominence during the fifth to seventh centuries as a key trading settlement with links to the Byzantine world. The site is therefore archaeologically sensitive, and all inspection pits were excavated by, or under the supervision of, an archaeologist.
Due to its exposed coastal location, the site is closed during severe weather events.
Ramboll’s geotechnical involvement in the bridge project
Ramboll was first involved at Tintagel in 2000, carrying out a stability review of the cliff faces which detailed risks associated with the site’s development. Engineering geology and geotechnical specialists from our Ground Engineering South team completed a further study, which recommended geotechnical investigation works required for potential bridge solutions, in 2013.
The subsequent commission for the Ground Engineering team included:
- Scoping, managing, procuring, and technically supervising the geotechnical investigation works, which included rotary boreholes and rock face mapping on both the mainland and the island.
- Assisting with the geological impact assessment which will form part of the overall Environmental Impact Assessment (EIA) for the scheme.
- Detail design of the foundations to support the bridge abutments.