Client: Isle of Wight Council
Project: MMC Diving Services
Principle Contractor: Ringway and Island Roads
Contractor: MMC Diving Services
Duration: 3 Weeks
Date posted: 08-11-2019
MMC Access team won the tender to undertake the works on the Cement Mills Viaduct, this is a 9-span bridge approximately 75m long overall. It was originally built as a railway structure, carrying a single line track between Newport and Cowes on the Isle of Wight.
The original superstructure comprises riveted plate, girder main and transverse beams supported by circular column piers. The structure was subject to a re-decking contract in 2007, when the original timber decking was removed and new galvanised steel transverse beams with new steel parapets were added to support a widened deck improving the popular cycle route.
The scheme requirements included the Installation of a suitable means of access to carry out localised paintwork repairs to the main bridge deck and cross-head beams. All other methods of access considered were intrusive, expensive and would have required a path closure causing disruptions to the many regular users.
Our methodology had to provide the client, Environment Agency and Natural England with the confidence that we could undertake this project using sufficient protective measures to prevent pollution of the watercourse, while also avoiding any need for supports from the river and reed beds below. This was particularly sensitive as the nature of the river below was an SSSI and RAMSAR site.
MMC designed and made custom capture collars for each pile and a large catchment net for the underside of the bridge. This also provided a stable platform to assist with work positioning for the access team helping to reduce the risk of suspension trauma from five engineers suspended for long days in harnesses.
The team under took localised surface preparation of all of the areas of corrosion to ferrous sections, including piers, cross-head beams, and main beams, along with localised removal of any unsound existing paint coatings using needle guns and de-scaler, all of which needed to be cleaned and abraded back to sound steel in preparation to paint. MMC work to the IRATA international Code of Practice (ICOP) and MMC Rope Access Procedures are always followed, specifically two independent points of attachment and indisputable anchors points.
Under the Construction Design Management Regulations (CDM) MMC provided the welfare in a secure compound away from public access.