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Pont Fawr (Llanrwst Bridge)
River Conwy, Llanrwst, Conwy, Wales, UK
Pont Fawr (Llanrwst Bridge)
associated engineer
Not known
date  1634 - 1636
UK era  Stuart  |  category  Bridge  |  reference  SH797615
ICE reference number  HEW 164
photo  © Crown copyright: Royal Commission on the Ancient and Historical Monuments of Wales | © Hawlfraint y Goron: Comisiwn Brenhinol Henebion Cymru
The three spans of Pont Fawr rise elegantly over the River Conwy carrying the B5106 between Llanrwst and Gwydir Castle. Its central arch had the largest span in Wales when built. The bridge’s design is popularly attributed to architect Inigo Jones (1573-1652), though this is not proven. Now a Scheduled Ancient Monument and Grade I listed building, it remains in continual use.
The present bridge was completed in 1636, but it was not the first bridge at this location. The original was probably of timber, and before that a ford crossed the river here. In 1626, the first bridge was declared unsafe. The 1627 General Sessions for Denbigh record the bridge had long been ... "in the greatest decay so that neither the King's subjects, nor horses, carts nor carriages, could come and go without great danger to life".
Welsh topographer Richard Fenton (1746-1821), writing in the early 19th century, describes in "a record of the Quarter Sessions for Denbighshire, that this Bridge, having become ruinous, was directed to be rebuilt by a letter from the Privy Council in the 9th year of Charles the First [i.e. 1634] … according to an estimate which amounted to £1000, to be levied equally on the Counties of Denbigh and Carnarvon". In 1634, four Lancashire stonemasons were contracted to construct a new bridge.
It is said to have been built for Sir Richard Wynn (1588-1649) of Gwydir, who paid for the Gwydir chapel in Llanrwst church in 1633. By tradition, the bridge’s design has been credited to Inigo Jones, apparently deriving from a statement made by Thomas Pennant (1726-98) in his Journey to Snowdon of 1781.
While it is true that Jones was Surveyor of the Board of Works at the time of its construction, Pont Fawr is not mentioned at all in the entry about Jones in Sir Howard Colvin's (1919-2007) seminal work, A Biographical Dictionary of British Architects, 1600-1840. So it seems unlikely that Jones was involved. It’s also possible that the design draws inspiration from Andrea Palladio's (1508-80) designs for three-arch bridges.
Pont Fawr (Great Bridge) is also known as the Shaking Bridge, as it vibrates if the parapet is struck above the central arch. It is constructed of local stone with sandstone voussoirs and parapets.
The steeply ramped bridge is 51.5m long, with flared approach walls. It is only 4m wide between parapets. The three segmental arches have spans of 13.7m, 18.3m and 13.7m, and the central arch rises 4.6m. The two river piers include V-shaped pointed cutwaters and road-level refuges on both sides.
The construction of the 460mm deep arch rings is unusual. The lower voussoir ring is of standard shape with a slight inward taper. However, the second voussoir ring — formed using 100mm by 510mm slabs — is cut to the curve with the long concave faces of the slabs laid downwards on top of the lower ring.
Stone tablets bearing the date 1636 are attached to the outside of the parapets in the centre of the bridge, rising slightly above the chamfered coping stones of the parapet. The north side plaque is carved with the Stuart arms and the initials CR (Carolus Rex, or King Charles). The south side plaque has the three feathers of the Prince of Wales with the initials CP (Carolus Princeps, or Prince Charles).
Apparently, the keystones for the central arch were positioned upside down during construction. The arch allegedly collapsed on the bridge’s opening day and had to be rebuilt.
The west arch collapsed in 1675 and was rebuilt but, in 1678, the Caernarfonshire Justices spent £15 on further bridge repairs. In 1702, the bridge was again in need of repair, being "ruinous and in great decay". Work was undertaken in 1702-03, at an estimated cost of "not less than £90". A stone on the inner east parapet dating from this time is inscribed with the initials TR, which are presumably the mason's initials.
To celebrate the tercentenary of the bridge (1936), a bronze sundial was erected on the centre of the eastern parapet, unfortunately at a spot where the narrow roadway and passing traffic make it inadvisable for pedestrians to linger.
Pont Fawr is a Scheduled Ancient Monument and has been a Grade I listed building since January 1951. It still carries road traffic, though subject to a weight restriction of 18 tonnes.
In 2013, the bridge was closed for emergency repairs after a bus collided with the south east corner of the parapet. Long vehicles find it difficult to negotiate the sharp turn onto the bridge from the A470 on the east side of the river.
Research: ECPK
"Tours in Wales (1804-1813)" by Richard Fenton, edited by John Fisher B.D., The Bedford Press, London, 1917
reference sources   CEH Wales

Pont Fawr (Llanrwst Bridge)