document: This phase was completed in 2005. Previous contracts had been procured with the contractor providing the detailed design. For this system the design was undertaken by Mott MacDonald. It was developed by looking at the systems installed previously and calculating what was actually required to achieve cathodic protection of the piers. This resulted in a significant reduction in the number of zones and monitoring probes. The varying amounts of steelwork in the beams had previously lead to up to 5 zones per beam, with multiple layers of mesh to achieve the design current density. On review of the data the operating current density was similar in all zones and so this was reduced to a single zone per beam. The encapsulation was susceptible to ASR and contained post tensioning and so it was decided to use a galvanic system based on Galvashield CC anodes from Fosroc. Our design did not include an option to allow depolarization of the galvanic system, but the contractor supplied one, such that the anodes could be remotely disconnected. The control unit was from Electrotech CP and operated via a broadband connection provided by the contractor.
doc_bio_tags: O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O B I I I I I I I O O O O O O B I I I I O O O O B I I I I I I I I I O B I I I O O O O O O O O O O O O O O B I I I O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O O B O O O O O O O O O O O O B I O O B I I O O O O O O O O O O O B I I I I O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O
extractive_keyphrases: asr broadband connection cathodic protection of the piers data depolarization of the galvanic system detailed design encapsulation galvanic system galvashield cc anodes looking at the systems installed previously and calculating multiple layers of mesh significant reduction in the number of zones and monitoring probes varying amounts of steelwork
abstractive_keyphrases: systems installed previously