Bideford Longbridge is a Grade One listed 24 span medieval masonry arch bridge spanning 190m over the tidal estuary of the River Torridge.

Scope of Works:

• Installation new underbridge lighting.
• Design and installation of an impressed current cathodic protection (ICCP) system for the cantilever sections.
• Partial demolition and reconstruction of reinforced concrete elements

The ICCP system was designed using a combination of mixed metal oxide coated titanium mesh and discrete mixed metal oxide coated titanium tubular anodes to ensure a uniform current distribution.

While the scaffold was being erected a full scale trial mock up of the cantilever was constructed to demonstrate and prove the methods and materials CRL proposed to use in the contract. The demonstration repairs carried out on this mock up were cored to determine full compaction and bond to the original concrete. Also the resistivity of the repairs was measured to ensure compatibility with the original concrete and the ICCP system.

The ICCP system is one of the most challenging schemes ever undertaken by CRL since it first started installing CP on the Midland Links motorway network in the late 1980s. A combination of anode systems, services below and above deck, and restricted scaffold access in a tidal zone is challenging the management and site operative skills.

Devon County Council’s Chief Bridge Engineer, Nick Bott commented that a high level of liaison throughout the design, consultation and procurement processes was required to successfully deliver this highly complex project, with the minimum disruption to the public.

Client: Devon County Council

Project Value: £2.0 million