Defective concrete at the top of the tower left steel elements exposed in an aggressive saline environment.
Background
Royal Sovereign Lighthouse was built in 1971. Situated seven miles to the south of Eastbourne in the English Channel, it is a unique and instantly recognisable structure complete with its own helipad.
The design is complex, as the reinforced concrete elements rely on a post tensioned system. A full structural survey undertaken in 2008 confirmed subsurface corrosion. By 2010, major structural works were essential if the integrity of the lighthouse, now entering it’s fifth decade in one of the most aggressive of environments, was to be maintained.
The Solution
Having identified the potential for seawater to penetrate through to the post-tensioned tendons to initiate failure that would not be easy to predict, the EN 1504 Part 7 certified Steel Reinforcement Protector 841 was specified in combination with Monomix to complete the repairs. Monomix is a single component, high build polymer modified mortar which is certified to EN 1504 Part 3. It produces a structural grade, non-shrinking repair which is totally waterproof under 10 bar pressure, equal to 100 metres of water.
Client
General Lighthouse Authority, The Corporation of Trinity House
Project Profile - Royal Sovereign