The Ceiriog Viaduct, south east of Chirk, was built to carry the A5 road over the river Ceiriog and over the Welsh-English border. The bridge was built in the early 1990s for the Welsh Office Department, the contractors were Christiani & Neilsen and the engineers were Tony Gee and Partners. Tony Gee and Partners describe the viaduct as 'a high level, incrementally launched, concrete box girder, seven span viaduct. Situated in an area of scenic beauty, the design was subject to the approval of the Fine Arts Commission.' It spans 450 metres, is positioned 26 metres above the valley floor and cost approximately £5million to construct. In 1993 the Ceiriog Viaduct won a Concrete Society award.
Sources: tonygee.com; www.constructionnews.co.uk - article entitled 'Incrementally launched bridge under construction on the A5' published on 3rd August 1990
M. Ryder, RCAHMW, 15th January 2019.