Viaduct bearings being replaced
Work is now underway on a £1.6million project to replace bearings under the bridge deck of the Clyde viaduct.
The three-span, 90-metre, steel structure stands on three sandstone piers above the River Clyde near Uddingston and carries traffic on the strategically important West Coast Mainline, as well as local services.
Bearings sit between the bridge deck and the piers and serve to control movement in the structure and absorb stresses generated by trains travelling above.
With the viaduct now more than 140 years old, and given the weight and volume of trains using it on a daily basis, the existing bearings have begun to show signs of deterioration.
Jeremy Spence, Network Rail’s programme manager, said:“our structures are subject to a regular programme of inspection and routine minor maintenance which allows us to monitor their condition and react if any faults develop, or the condition deteriorates to a point where we need to intervene.
“Having reached that point on the Clyde viaduct, the challenge from an engineering perspective was to come up with a way to replace the bearings while keeping the railway open.”
A dozen sliding bearings – four on the east abutment and eight on the west pier – need to be replaced. The new steel bearings are one metre long and half a metre wide and only about 10cms deep, but weigh in excess of 140kg each. Because of their modern design, they are less bulky than those they are replacing and will be set on pre-cast slabs which will have a combined weight of around 1.5 tonnes each.
The team have been on site for three months now undertaking preparatory work on the bridge, before even touching the bearings themselves.
As well as creating the scaffolding and hoist system, the team have strengthened and braced the bridge