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CASE STUDY

Rehabilitation of the Maitlands River Pipebridge

Exposed Surface Coatings

Project Data

LocationSouth Africa
ProductsDenso Steelcoat 500™ System
DateFebruary 2015

Project Details

Denso were involved in the rehabilitation of the Maitlands River Pipebridge. The Original Pipebridge was built in 1948 as a single 670Ø pipe known as the Church Hill Pipeline. In 1959 a second 1200Ø pre-stressed concrete line was added to the bridge.

In 1964 floods washed away the centre pier and the pier had to be replaced. The concrete pipe was also replaced with a 1168Ø steel pipe. In 1979 floods washed away the southern abutment and three piers subsided. A new abutment and piers had to be constructed. In 1981 floods caused another three piers to subside.

All the original piers where then replaced and a new 1200Ø, 20mm thick welded steel pipeline was installed to replace the original 670Ø. The 20mm wall thickness was selected so that in the event of floods washing away the piers again the pipeline would be able to support itself.

In 1982 a tender was put out for the wrapping of the pipeline using a Denso™ Tape with a cement slurry second wrap to provide mechanical protection. Since then the bridge and pipeline has undergone very little in the form of maintenance and there were signs of deterioration starting to appear along the ±700m x 1200Ø stretch of pipework.

Due to the pipeline being in an environmentally sensitive area, right on the beach, the work was going to be challenging. First the original wrapping had to be removed and the pipe surface cleaned before application of the Denso Steelcoat 500™ system could be applied. Because of the large diameter of the pipe it was decided that the cigarette wrap method of applying the tape would be most suitable for the project.