A team from Owen Williams Railways is currently undertaking a breathtaking and nerve testing detailed structural masonry inspection – by abseiling down Newcastle’s High Level Bridge.
The project is part of a 10-year contract awarded in 2003 by Network Rail, to examine structures on their London North Eastern Territory. This involves approximately 10,600 structures consisting of bridges, viaducts, culverts, retaining walls and tunnels.
The Grade 1 listed structure is a combined railway and road bridge with two decks, carrying traffic over the River Tyne. The railway runs above the road, supported by six ribbed bowstring arches and eight masonry approach arches, supported on sandstone piers.
Designed by Robert Stephenson, construction was completed in 1849. The structure provides 25 metre clear headroom at high water; the rail deck is 34.14 metres above high water and it is 425 metres long.
Six main spans, each of 38 metres, extend across the River Tyne, with smaller masonry approach spans/arches. Five masonry piers, founded on massive timber piles, support the six main spans, each of which consists of four cast-iron ribs tied with flat, wrought iron tension chains. The rail deck above is supported by cast-iron columns rising from the main ribs while the road deck is slung below.
To inspect the structure, Owen Williams Railways is employing a combination of access techniques including abseiling, traditional access scaffolding and a 50 metre, lorry mounted, mechanical elevated working platform.
Work is due to be completed by Mid December 2004.