Bridges from Y Gelli/Hay-On-Wye to Cae-Gaer
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I hope that this page will eventually include photographs of all the Wye bridges upstream of Whitney-on-Wye.
From just below Hay-on-Wye upwards, the river Wye is entirely in Wales.
4594 near Erwood
40 Pont as Ithon A470
Rhaeadr Gwy foot bridge
Rhaeadr Gwy road bridge
Rhaeadr Gwy foot bridge
Pont Marteg foot bridge
Pen-yr-ochr - Dolhelfa
55 Clochfaern ?
60 Pont Rhydgaled
Y Gelli Bridge / Hay-on-Wye Bridge
After the interesting bridge at Whitney-on-Wye, the bridge at Y Gelli, or Hay-on-Wye, the famous town of books, is rather a disappointment, especially as it is in a really grand setting, crossing a beautiful stretch of the Wye between high banks. It is based on a large number of concrete I-beams, bridged with more concrete. The I-beams rest on cross beams which are supported by octagonal concrete piers; these offer less resistance to flow than rectangular ones of the same cross section. They probably create a little less turbulence, though during the times of flood when it matters, the water is already so turbulent that the piers probably have no effect. Underneath the deck you can find some small X-trussing, presumably to aid rigidity. The second picture shows how debris can build up in front of piers and greatly increase drag.
Glasbury, with a name that is part Celtic, part Saxon, lies in both Breconshire and Radnorshire. The Welsh name is Y Clas ar Wy. It's bridge comprises six concrete haunched beams, which on inspection are found to be ribbed. One of the pictures illustrates the extensive effect of scouring around a bridge pier: the notice in another warns bathers of the deep holes which are of course unseen when the water is higher. The appearance of the piers and the underside of the beam reveal that the bridge has been widened. This bridge replaced a masonry arch bridge. Note the very low level of the river. There may have been a bridge here as long ago as 1665.
This bridge of four masonry arches was a toll bridge until 1934. This bridge is an excellent example of the use of narrow piers, with the thrust being carried through the arches to the abutments.
This suspension bridge, built in 1922, looks at first sight like a rather substantial footbridge, but it could in fact carry one vehicle of up to five tons at up to four miles per hour. The weight limit has been reduced to two tons. The bridge is narrow, and there is no room for a car to pass a pedestrian. Like some other Wye bridges, this one cannot be photographed properly from the side because of the trees. A suspension bridge was probably an economical choice, and it avoided placing piers in the river.
Builth Wells Bridge
The 18th century bridge at Builth Wells has six fine masonry spans, with relatively small cutwaters, which are fitted on the upstream side with stout steel fenders to provide protection from debris. Unlike many bridges, this one has round cutwaters. At the centre of the bridge there is one pedestrian refuge on each side. The arches have been reinforced by a layer of concrete in the soffit. The bridge carries very heavy vehicles on the A470. Views of the bridge and from the bridge are beautiful. Builth Wells, a pleasant and thriving town, is the home of the Royal Welsh Show. Many other shows are staged on the large RWS showground.
The pictures below show a few of the many variations in photographs that can be made by changing location, weather and time of day. Note the plants growing on the slopes at the tops of the cutwaters. In the long run, the presence of plants is detrimental to masonry, for the roots penetrate into the mortar, allowing the ingress of water, which with repeated cycles of freezing and melting can generate cracks. Perhaps this is origin of the name saxifraga, though in fact those plants are far more likely to occupy cracks than to generate them. Eventually, the roots of plants can actually displace bricks or blocks to the extent that they fall off.
Builth Wells possesses another fine bridge, a very tidy cable-stayed bridge over the Irfon, a tributary of the Wye. Like many other bridges in the region, it is difficult to photograph effectively because of the trees lining the river banks. The design is very tidy in every way - everything is kept simple. The cables are anchored to the deck, which is in turn anchored to large concrete blocks.
Upstream from Builth Wells the railway from Builth Road station crosses the Wye. The plate girder spans are modern replacements. The southern pier is pierced by post-tensioned bolts.
A set of wooden planks enables people to cross most of the width of the river. They are probably for the use of anglers. No doubt they have to replaced after the river has been in spate.
A modern concrete bridge crosses the Wye, carrying the B4358. The continuous concrete beam is divided into three spans by two piers. The picture shows a mass of tree branches remaining from the last flood. When the river is higher, these accretions greatly increase the effective width of the piers, decrease the effective span, and destroy the smooth lines of the piers. The narrow piers, tapered to fairly sharp noses, offer little resistance to the flow of water, but this narrowness probably increases the probability that branches will be snagged on the piers.
The watermarks on the piers indicate previous high water levels. The slope of these marks suggest the way that the water is held up by the wood, and how it falls away behind. Turbulence in time of flood can create strong vibrations in bridges, which can be felt by pedestrians. Remember that each cubic metre of water weighs one tonne, and that it may flow at well above a fast walking pace. All the water that meets the piers and the masses of debris has to be deflected. Don't be misled by the apparent calmness of the water in the picture. Swimming in the Wye can be dangerous because of the swirling currents, and because of the great variations in depth caused by scouring and by rock erosion.