Gabions and site assessments
Constructing with gabions is a highly sustainable civil engineering application that ensures structures blend in with the environment, and it all starts with a professional design approach that maximises labour and minimises costs. By Alastair Currie
When it comes to gabion structures, ensuring their integrity depends on a combination of correct material specification, design and construction technique. Older gabion structures need to be revisited some years down the track where galvanised wire was used in their original construction, especially for river protection and hydraulic structures.
“For any potentially corrosive environment, we always recommend Galfan-coated, soft temper steel wire for gabion construction,” explains Louis Cheyne, managing director of Gabion Baskets – a company that manufactures and supplies gabions and supporting geotextiles, along with design, training and installation services.
“A further PVC coating is then applied during the manufacturing process to provide added protection when these products are installed in polluted environments where soils or water are acidic. This PVC coating usually has a nominal thickness of 0.50 mm, and helps to significantly preserve gabion structures for many decades. However, the same cannot be said for standard galvanised wire, which will inevitably fail.” Cheyne points out that climate change impacts need to be factored into future designs and remedial works. The increase in extreme floods and droughts, for example, has led to the rapid deterioration of gabion structures in river systems where incorrect techniques and products have been specified. Retaining wall installations also need attention for the same reason.