Design and Engineering
For the 1875 rebuild, of Semple’s Essex Bridge, which previously stood on this site, the old superstructure was taken down and the bridge rebuilt on the old abutments and piers while widened. It was also necessary to reduce each arch adjacent to the north and south quays to allow for the construction of the main drainage sewers.
The foundations according to Semple were built to ‘last as long as the Sugar Loaf’. To do this he took care to ensure that they would not be undercut - achieving this by driving a row of timber sheet piles at both sides of the bridge, and paving the interval between them with a thick course of rubble masonry, which he called his ‘thorough course’. He had great difficulty in driving the piles for a cofferdam because of loose rocks. When the cofferdam was in place he had no difficulties in keeping it dry and secure, the hydraulic head being in excess of 6m at high tide. His cofferdam was composed of two layers of parallel timber sheet piles into which was placed ‘blue’ clay. The enclosing timber piles used to build this were 150mm dovetailed oak piles driven to rock which were cut off at the surface of the foundations on completion.
It was decided, for this 1875 rebuild, that the bridge should be widened and the gradients to the centre of the bridge removed as they were too steep. A further reason for reshaping the bridge was the need to provide space on the quays to accommodate a new drainage system which the city was planning to build.
The three large arches are segmental in shape while the two smaller arches springing from the abutments are semi-circular. The side circular arches were built first and then the three elliptical centre arches were built together to prevent movement of the piers from the horizontal thrusts. The total span is 52m. The haunching is of rubble masonry.
There are four piers with cutwaters on both faces of the bridge. Projecting out from the chamfered upper portion of each pier is a small granite corbel. Eight large decorative cast-iron consoles rests on the stone corbels. Each console is shaped like a scroll or volute and decorated with foliage motifs including pateras-and-rosettes and acanthus leaves. They carry the parapet and path on both sides of the river out over the arches. The footpaths are cantilevered 2.4m out from the face of the bridge.
The parapet is divided into five sections of riveted iron lattice work, alternating with six cast-iron dadoes with nail-head panels. The overall height of the parapet is 1.10m. There are six cast-iron parapet standards. They are adorned with rampant seahorses and a flourish of foliage and geometric motifs, including acanthus, volutes, linear mouldings. At the rise of the bridge on the east and west sides there are bronze commemorative plaques which read as follows: ‘Essex Bridge erected 1755. Rebuilt by the Dublin Port & Docks Board 1875. Renamed Grattan Bridge by the Municipal Council 1875. The Right Hon. BLE Peter Paul Mc Swiney. J.P. High Sheriff, Bindon B. Stoney Engineer, V.J. Doherty. Contractor.’
The services are carried in an arch vault because of the small depth between road surface and arch sheeting. The cost of the rebuilding of the bridge was £25,380. Grattan Bridge was opened though not fully completed after 15 and a half months of construction. The contractor was W.J. Doherty, who later built both O’Connell Bridge and the swivel Butt Bridge, under Bindon B. Stoney, Dublin Port and Docks Board Engineer.
During 2002 it was found that the deck was deteriorating due to ingress of water and that urgent repairs were required. As a result the deck and footpaths were replaced and the bridge returned to full service.