County: Meath Site name: Bective Bridge
Sites and Monuments Record No.: ME031-042 Licence number: Unlicensed
Author: Niall Roycroft
Site type: Bridge Strengthening works
Period/Dating: —
ITM: E 685989m, N 759809m
Latitude, Longitude (decimal degrees): 53.581103, -6.701440
The engineer and contractor made a detailed study of the cleaned west refuge (the refuge coming away from the bridge) and confirmed that taking down and rebuilding was a better solution than stitching. The refuge within the crack area was taken down by hand stone by stone and the construction method noted.
At the edge of the crack area it was seen that the whole area within the crack zone was a rebuild using a light grey sand-cement modern mortar that had been built onto the surrounding and underlying builds that were old and used a yellow-brown lime mortar. Therefore, the reason for the whole piece breaking off was probably due to different builds. This situation is perhaps repeated in the east refuge but not so severely and the works will simply stitch these cracking parts back together.
The base of the west refuge was a thin, floating slab of concrete over loose stones. It was not tied to anything and had no structural benefit. The slab was removed and a new mass concrete slab was poured that was tied to the surrounding refuge masonry using steel bars. No other parts of the concrete was fixed so there is capacity for the usual movements.
Concerning drainage - all the weepholes on the south side had been blocked (some with stone) perhaps when the Eircom duct (0.25m wide) had been laid - only four were found. There were 11 weepholes on the north side. It was decided that the best solution was to seal the bridge deck and gutter all the drainage to the four corners of the bridge, then build gullies and reuse existing weepholes for outflow. Any weepholes still above tarmac level - which is most of them on the north side, would still have their opening exposed and used.
The west refuge was rebuilt by an expert stone mason.
A few examples of the bridge road surfacing sequence were recorded: on the bridge
crown in the middle of the humpback, the old gravel and chippings road surface had been worn away. The gravel and chippings road surface was in the west refuge base. So there does not seem to have been any specific paving in those areas. Similarly, there is no evidence on either side for a decorative roadside gutter of larger cobbles (as would often occur in a town or village).
The north parapet seems to have been entirely rebuilt at some stage. This might explain the differences in the weephole arrangements to the south facade. At the base of the new service trench on the north side, there was a step out 0.2m at the parapet base, where the old bridge façade was not matched by the present parapet. Parapet rebuild was also noted in the flaring (in plan) on the east side of the bridge.
There is also a lip on the south façade, eastern half of the entire bridge, at the base of the parapet which coincides with a large area where there are no weepholes. This probably also means a rebuild at some stage and could explain why the east refuge has a different construction to the west refuge. The numerous weepholes in the north parapet and lack of weepholes in the south parapet probably mean that some cross-fall (to the north) drainage was designed into the bridge during these previous works.
c/o Meath County Council
