Swing Bridge Over River Ouse

Swing bridge over River Ouse, Southease

This swing bridge, dating from 1880 and designed in 1878 by Henry E Wallis (CE) of Westminster, was constructed by Shaw & Co. with 20th-century timber replacement and safety additions.

The bridge was built to replace an earlier structure approximately 10 metres upstream, following the canalisation of the River Ouse between 1791 and 1795, which created the Lower Ouse Navigation designed by William Jessop and supervised by Cater Rand, a Lewes schoolmaster and civil engineer. This canalisation work cut off a lengthy meander of the river between Itford and Durham Farms and severed farmland, necessitating statutory provision of a bridge at Southease. The original bridge incorporated a swing span to permit the passage of masted vessels. In 1988, under parliamentary powers, the bridge was fixed in position to prevent large vessels sailing further up river, although the pivot table remains in position.

The bridge is a three-span structure of wrought-iron bowstring trusses 3.62 metres apart, with a total length between abutments of 43.2 metres. The western span of 13.8 metres is fixed, while the remaining two spans of 29.4 metres centrally pivot. The bridge ends are carried on brick abutments with curved wing walls having projecting piers in red brick in English bond with stone copings. The embankments, 6 metres wide at the top with a side profile of 1:1, were constructed at an incline of 1:20. The top of the bridge deck was designed to be 2.75 metres above high water.

The two intermediate piers are constructed in the waterway from groups of cast-iron columns in two lengths, bolted together through the flanges. The western pier between the fixed and swinging spans consists of two groups of three columns with cast-iron caps linked by a cast-iron transom girder and diagonal cross bracing. Wrought-iron tie-bars are attached to the cast-iron caps and connected to concrete pads built into the west bank via iron shoes. One of these tie-bars has been disconnected and replaced with another anchored into the river bank.

The eastern pier supporting the swinging section comprises eight columns surrounding a central column supporting the king post. Cast-iron cruciform horizontal bracings link the columns at mid-height. A radial stiffening frame with eight spokes is collared to the piles with raking struts attached to the cap of the central column. The columns support the pivoting mechanism, based on a circular geared cast-iron rack in the form of a giant spur wheel with eight spokes. An upper cast-iron 'I'-section ring with eight spokes is bolted to the underside of the superstructure. Between the two rings is a race of twelve unflanged wheels whose axles are attached to a wrought-iron ring, functioning as a turntable. The bridge was operated by a small pinion on a vertical shaft engaging with the rack, finishing with a square-ended spigot. A 'T'-shaped capstan bar was presumably supplied for two people to operate the bridge, but this no longer survives.

The spans are curved bowstring steel 'X' pony trusses, 14 bays long, with the end bays filled with solid plates and the remainder with vertical posts of paired iron tees with diagonal compression and tension members. The top booms are braced by 'U'-frames comprising rolled-steel channel cross girders beneath the deck, which appear to be a later addition.

The deck comprises wrought-iron 'I'-beams to whose flanges rolled-steel channels have been bolted at a later stage. Longitudinal wrought-iron girders are augmented by wooden intermediate beams, all supporting softwood timber decking laid flat, open jointed and bolted to the girders. The timber decking has been replaced throughout the bridge's life and is not original. A handrail has been fitted on the tops of the trusses to raise the height of the balustrades. The original handrails, as indicated on the Wallis drawings, ran only from the third points of the trusses at the level of the summit of the bowstrings and were supported on cast-iron stanchions.

Sets of timber fender piles, upstream and downstream, protect the east pier against shipping when the bridge is open. Each comprises three piles with intermediate and top rails and raking struts. A further row of ten piles and rails connects the upstream and downstream fenders with a raking shore to each pile. Further sets of fender piles are located upstream and downstream of the west pier, with three piles to each and two intermediate piles between them with rails matching those at the east pier.

A wooden boarded platform surrounds the top of the east pier, carried on six joists clamped to the piles. This provided access to the operating gear for maintenance.

At each end of the bridge are two pairs of steel gates in a derelict state, retaining central target panels warning traffic to stop.