Broadmeadow viaduct
Broadmeadow viaduct | |
|---|---|
 Broadmeadow Estuary (bridge at right) | |
| Coordinates | 53°27′N 6°10′W / 53.45°N 6.17°W |
| Carries | Dublin - Belfast railway |
| Crosses | Broadmeadow estuary |
| Locale | Malahide, Ireland |
| Characteristics | |
| Material | Stone piers & prestressed concrete spans |
| Total length | 180 metres (590 ft) |
| Piers in water | 11 |
| Location | |
 | |
The Broadmeadow viaduct, in Ireland, carries the main Dublin to Belfast railway across the Broadmeadow Estuary, about 13 kilometres north of Dublin, just north of Malahide. It is approximately 180 metres (600 feet) long and it is a section of a longer crossing constructed as an embankment.[1] The viaduct carries around ninety trains, including commuter services and heavy freight, per day and it is the sole rail route between Dublin and Belfast. It has had a history of problems with its foundations being scoured out by strong currents[1].
History
The present structure is the third on this site. The first was built in timber for the Dublin and Drogheda Railway in 1844. Its stability was badly affected by erosion of the river bed around the piles and, after short-term remedial work, it was replaced in 1860 with a new structure of wrought iron spans on masonry piers. This sufficed until the early 1930s when new locomotives (4-4-0 Compounds) required strengthening of the piers and continued maintenance. Additional ballasting of the piers was also needed. The sea air caused deterioration of the wrought iron and these spans were replaced during 1966-1968 with the current prestressed concrete structure. At this time, the tracks were laid on ballast, reflecting modern practice.[1]
Collapse
On Friday 21 August 2009, at 6:30pm, a 20 metre section of the viaduct collapsed. Some reports state that the collapse started while a passenger train was passing over it, others say shortly after. The train was not derailed and no one was hurt: the driver raised the alarm. It has been estimated that repairs will take a minimum of three months, possibly a year, with curtailment of all services.[2] The competence of Iarnród Éireann's maintenance regime has been questioned and there have been previous critical reports of the viaduct's structure[3]. Iarnród Éireann stated that the structure had been inspected three days previously[2]. Erosion had been reported by an Irish Sea Scout leader who later opined that a superficial inspection might have missed scour damage below water level[4].
Official estimates of three months to repair the viaduct (by reinforcing the seabed and replacing the collapsed pier) and restore rail services are being adhered to[5]. However, unattributable comments by structural engineers are much more pessimistic[6]. Because the estuary is a Special Area of Conservation (SAC) and a Special Protection Area (SPA), a full environmental impact statement (EIS) is necessary and, if a planning application is also required, obtaining the necessary permissions alone could take more than three months. In addition, the stability of the remaining structure needs to be proven. A long term solution, perhaps a new longer span bridge, will be needed.[6]
References
- ^ a b c Torpey CEng, F.I.Struct.E, FIEI, Niall V. (3 August 2004). "Malahide". Irish Railway Bridges-Part 2. Irish Railway Record Society. Retrieved 26 Aug 2009.
{{cite web}}: Cite has empty unknown parameter:|coauthors=(help)CS1 maint: multiple names: authors list (link) - ^ a b McCreary, Matthew (24 August 2009). "Collapse of Belfast-Dublin line will affect thousands of commuters". Belfast Telegraph. Retrieved 26 August 2009.
{{cite web}}: Cite has empty unknown parameter:|coauthors=(help) - ^ "Pressure mounts on Irish Rail to explain 'systems failure'". Irish Independent. 24 August 2009. Retrieved 26 August 2009.
{{cite web}}: Cite has empty unknown parameter:|coauthors=(help) - ^ "Company warned on bridge erosion". BBC. 26 August 2009. Retrieved 26 Aug 2009.
{{cite web}}: Cite has empty unknown parameter:|coauthors=(help) - ^ McGreevy, Ronan (10 September 2009). "Viaduct on track for rail services by November, [[Oireachtas]] members told". Irish Times. Retrieved 25 Sep 2009.
{{cite web}}: Cite has empty unknown parameter:|coauthors=(help); URL–wikilink conflict (help) - ^ a b Buck, Brendan (30 August 2009). "No quick fix to bridge the gap". An Irish Town Planner's Blog. Retrieved 25 Sep 2009.
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