Hidden Void Investigation Cowburn & River Yarrow Viaducts

Neary Rail recently completed 2 orders under our LNW Civils Framework to carry out intrusive hidden void investigation works at Cowburn Viaduct, near Edale and River Yarrow Viaduct, near Chorley.
Network Rail supplied a desk top survey which had indicated that hidden voids may be present in both structures and therefore required an intrusive survey to be carried out by Neary Rail.
The scope of works involved EA/LA liaison, as both viaducts cross rivers, the provision of high level access to the arch, pier and spandrel areas, core drilling of the structures at predetermined locations to depths of up to 2.5m, undertaking a CCTV survey of all cored holes, reporting on our findings and making good of the structures on completion.
At Cowburn Viaduct, a temporary bridge and tube clamp handrails were installed to allow staff to access the East abutment, with high level access to other areas provided by scaffold towers and a telehandler with personnel basket. Traffic Management was utilised to allow access to the West abutment. 95 percent of the drilling works at Cowburn Viaduct were carried out in house, with a specialist drilling contractor used for a small number of cores over 2.5m in length.
At River Yarrow, high level access was provided by scaffold towers, with all coring works carried out by a specialist drilling contractor.