GLENDUN VIADUCT

The Department's description

Exterior description and setting

A triple-arched masonry road bridge of 1839 over the Dun River on the Cushendall - Ballycastle road.
This bridge is constructed in sandstone throughout. Its abutments and piers are of sandstone blocks brought to courses, with plain quoins. Attached to the up- and downstream faces of the abutments and piers are shallow buttresses of randomly-size blocks which taper inwards on both their faces and edges as they rise. The buttresses are embellished with stepped, vee-jointed sandstone quoins, the faces of which are rusticated and margined.
All the arches are of semicircular profile and have voussoirs detailed as the buttress quoins. The middle arch is the tallest and widest and spans the actual river. The flanking arches are of identical size: the N one spans a minor road along the left bank of Glendun whilst the S one is dry in normal circumstances. As none of the piers is footed in the river, no cutwaters were necessary. The arch soffits are of coursed sandstone blocks, with a row of projecting stones below arch spring level on which the falsework was set during their construction. Moulded sandstone string courses run through each arch at spring level and continue around the abutment and pier buttresses.
The spandrels are of randomly-sized blocks brought to courses. A moulded sandstone string course runs across each face at the base of the parapets. The parapets are of regularly-coursed rusticated and margined sandstone blocks with similarly detailed oversailing copings with sloping tops. The parapets terminate in out-projecting piers which are an upward continuation of the abutment buttresses. There are identical out-projections along the outside faces of the parapets at the top of each pier buttresses.
The approach walls are of random rubble. A substantial earthen embankment carries the road across to the S end of the bridge.

Setting:
The bridge and road span the deep valley carved out by the Dun River and are surrounded to all sides by fields and patches of woodland.

Historical information

The 1832 OS map shows a dotted line of road on which this bridge lies, with the caption "new road in progress 1833". This was a continuation of the Antrim Coast Road from Larne to Cushendall northwards to Ballycastle and which was constructed 1832-42 by the Scottish engineer William Bald for the Commissioners of Public Works in Ireland. This bridge was also constructed by Bald, but designed by Charles Lanyon who was the Surveyor for County Antrim at that time. The plaque on this bridge attests to its completion in 1839. The new line of road on which the bridge is situated superseded a previous route via Clady Bridge, a short distance downstream, but which was much steeper.
'Glendun Bridge' is explicitly captioned on all editions of the OS maps from 1857 onwards.

References - Primary Sources:
1. PRONI OS/6/1/14/1. OS 1:10,560 map, Co Antrim sheet 14 (1832).
2. Datestone on bridge (1839).
3. PRONI OS/6/1/14/2. OS 1:10,560 map, Co Antrim sheet 14 (1857).
4. PRONI OS/6/1/14/3. OS 1:10,560 map, Co Antrim sheet 14 (1903-04).
5. PRONI OS/6/1/14/4. OS 1:10,560 map, Co Antrim sheet 14 (1922).

References - Secondary Sources:
1. W.A. McCutcheon, The Industrial Archaeology of Northern Ireland, plate 2.4 (Belfast: HMSO, 1980).
2. F.W. Hamond, Antrim Coast & Glens Industrial Heritage, p.79 (Belfast: HMSO, 1991).

Criteria for listing: architectural interest

A. Style
B. Proportion
C. Ornamentation
F. Structural System
H-. Alterations detracting from building
J. Setting
K. Group value

Criteria for listing: historic interest

R. Age
S. Authenticity
T. Historic Importance
V. Authorship
W. Northern Ireland/International Interest

Evaluation

This is one of the finest mid-19th C masonry arch bridges in the Province. The quality of its construction, as exemplified by its dressed sandstone blockwork and embellished dressings, represents the apogee of mid-19th C bridge design, here under the authorship of Charles Lanyon, the County Antrim Surveyor. Its semicircular arches, slender proportions, tapering buttresses, and setting deep in the Dun Valley all combine to accentuate its imposing scale.
It also has group value with neighbouring bridges along this line of road: Craigacat Bridge (HB05/03/029), Corratavey Bridge (HB05/04/001), Altheela Bridge (HB05/04/002), Bush Burn Bridge (HB05/04/003), and Altadreen Bridge (HB05/04/004).
The bridge's original fabric survives intact, albeit with a replacement plaque. Its association with the Antrim Coast Road scheme - which runs between Larne and Ballycastle and was the largest civil engineering project in Ireland in its day - also enhances its historical interest. This line of road on which it is situated enabled steeper earlier roads to be avoided and undoubtedly greatly facilitated social and economic connectivity throughout the area. This is the largest and most visually impressive of all the bridges on the Coast Road and of national significance.