Posted to News on 24th Jun 2007, 11:38
Girder clamps prove fast and versatile for bridge repairs
Bolt-on Lindapter girder clamps have been used for the refurbishment of the old Cement Mills Viaduct railway bridge on the Isle of Wight.
A recent project on the Isle of Wight called for the structural upgrade of an old railway bridge to create a practical and safe new cycleway and pedestrian path to support the local community and tourism. Prior to the upgrade there had been timber decking and chainlink fencing, both of which had deteriorated over time.
The project was designed for the Isle of Wight Council by Opus International's Fareham office. Key design considerations were cost-effectiveness, durability, and maintainability - combined with the need to protect reed beds below the viaduct that form part of the nature reserve on the site of an old cement mill.
With a span of around 80m, the bridge was originally constructed in the 19th century for the island's railway services; the structure is made from riveted beam sections. It was converted to a walkway following the closure of the island's railway lines in the 1950s and 1960s.
Bolt-on girder clamps
For this refurbishment, the previous walkway surface was stripped off to get back to the original compound girders. Galvanised beams were laid crosswise onto the two primary girders to provide a platform for the decking. These beams were attached using Lindapter's Girder Clamps, which simply bolted on - avoiding any need to modify the original structure. Epoxy-encapsulated plywood decking panels were then laid on top of these beams to provide the walkway surface, and a safety parapet was added.
Opus International's Project Manager, Andy Traves, explains his design: "For economy, flexibility of implementation, and maintainability, we decided on a highly 'componentised' design for the upgrade. The Lindapter clamps meant we could attach beams simply, without welding or drilling. The modularity of the design also makes it simple to maintain - a spare part can be made ready, and replaced easily and cost-effectively using local scaffolding."
Andy Traves knew that Lindapter clamps were suitable for the project, from previous experience with the products. It was desirable not to modify the original structure in order to avoid weakening it or opening corrosion paths. The clamps satisfied this objective, and also provided flexibility of positioning while the new surface was laid. This was important, as it only became clear where the rivet heads were located during removal of the old surface.
