Structures for the Dublin Light Rail
Abstract
The Dublin Light Rail system, designed by Sinclair Knight Merz in Melbourne and Dublin, includes an elevated section that follows the route of a former rail line and required reconstruction of a number of rail bridges. The original line was constructed in 1854 and closed in 1959. One section of the original line had been constructed on a 5m high embankment retained by masonry gravity retaining walls along each side of the embankment. The bridges cross roads and a canal that intersect the line. The previous bridges would have been wrought iron with a ballasted track, and the replacement bridges are steel with a reinforced concrete deck and direct fixation of the rails to a track slab on the bridge deck.
The considerations that influenced the design task included:
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The re-use of existing gravity stone abutments
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The re-use of existing gravity stone retaining walls along each side of the embankment
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The approval process administered by the authority set up to manage the contract
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The substantial increases in under-bridge clearance, by comparison with that which existed with the
former bridges
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Preservation of the character of these historically significant structures
This paper discusses how these constraints were handled and the structural solutions arrived at. It also
includes a brief reference to other significant structures constructed as part of the contract.
Author
John J. Noonan, Sinclair Knight Merz