Ha'penny Bridge - Dublin

As part of the restoration of the Ha’Penny Bridge across the River Liffey in Dublin, Metalock Engineering UKcarried out a series of magnetic particle inspection checks on various critical components and, using its Metalockmetal stitching techniques repaired the damaged parts for Irishenco Construction, main contractors for theproject.

The bridge is a List 1 structure in the Dublin Corporation Development plan and takes its name from the Ha’Pennytoll collected between its construction in 1816 to the toll ending in 1915. Although it’s present official name is theLiffey Bridge, it was originally the Wellington Bridge and comprises an assembly of elliptical arch ribs. Thesewere most probably cast in the Coalbrookdale Works in Shropshire from a design attributed to Thomas Telford.

Ha’penny bridge was closed for the restoration and a one-piece Bailey bridge located alongside for pedestriancrossing. The deck was removed and new sections fabricated to match the bridge’s distorted elliptical shape.New ductile iron ornamental railing sections have also been cast. The project included repainting in its originaloff-white colour.

Most of Metalock’s work involved tie-rod end caps, 43 of which had cracks and were repaired, and crackeddiaphragm rib plates. Additionally, Metalocking was used to repair construction webs and install new corbelsections to replace those that had broken off over the years. Most of the damage to the components thatneeded repair had been caused by expansion due to corrosion from moisture ingress following the breakdown ofjoint sealing materials.

Due to the significance of the bridge as an icon of the City, great care and attention was given to the restorationprocess and to allay the concerns of various heritage groups, as much of the original material as possible waseither repaired or refurbished. Only severely damaged and unusable components were remanufactured. Thetie-rod end caps, for example could have been replaced with new, but the Metalock process enabled effectiverepair of the originals, in-situ.

Most of Metalock’s work involved tie rod end caps.43 of which had cracks which were repaired andcracked diaphragm rib plates.