Wrapping with Butyl Rubber Tapes-An Innovative Corrosion Protection for Bridge Cables

According to the codes of the German Ministry of Traffic, the surface of new and existing locked coil ropes has to be protected against corrosion by an approximate 400 pm thick layer of paint. For the preparation of the rope surface and for the application of the different paint layers by a brush, access has to be granted over the entire rope length by fixed or movable scaffoldings-what in existing bridges may lead to important traffic disturbances. If, instead, the ropes are protected against corrosion by butyl rubber tapes-as known since a long time from the protection of pipelines etc.-the requirements for the preparation of the rope surface and thereby the amount of work and equipment may be reduced substantially. Owing to the application of these tapes by automotive and automatic wrapping robots, scaffoldings and lifting equipment are not needed any more, whereby important time and cost savings are achieved and the impact on the traffic is widely reduced. General considerations with reference to this innovative, robust and economic corrosion protection system are presented; the successful applications for two cable stayed bridges-across the Rhine between Kehl (Germany) and Strasbourg (France) and across the Kohlbrand in the Port of Hamburg-are described. An outlook on further possible applications is given.