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Queensferry Rolling-lift Bridge (Jubilee Bridge)
River Dee, Queensferry, Deeside, Wales, UK
associated engineer
Mott Hay & Anderson
Sir Basil Mott
R.G. Whitely
Adam Hunter
date  February 1925 - May 1927, opened 24th November 1926
UK era  Modern  |  category  Bridge  |  reference  SJ321687
ICE reference number  HEW 1317
The double-leaf Queensferry Rolling-lift Bridge is the only bascule bridge in North Wales. It crosses the River Dee west of Chester, replacing a late Victorian retractable bridge and a chain ferry before that. Now fixed closed, the bascule bridge continues in use and is a Grade II listed structure. It is in good repair.
The Dee at this point follows an artificially straight course from Shotton to Saltney between near parallel embankments around 137m apart it was canalised in 1732-36. The river is tidal at the bridge site, with a spring tide range of approximately 3m. Before the first bridge was built, people crossed using a chain ferry (known as the lower ferry), or they used the upper ferry near Saltney.
The first bridge was constructed in 1895-97 a retracting bridge of iron and steel. It was named Jubilee Bridge to commemorate Queen Victoria's diamond jubilee (1897). Traffic increased when Garden City was built (1910 onwards) to house workers from the John Summers & Sons Ltd steelworks at Shotton, and soon a larger bridge was needed.
The bascule bridge was constructed upstream of the old one, which was kept open during the works but demolished later. Also named Jubilee Bridge, or Queensferry Bridge, as well as Queensferry Rolling-lift Bridge, it is known locally as the Blue Bridge on account of its blue paintwork. The site is some 1.3km south east of Hawarden Swing Bridge (SJ310693), which takes the railway from Hawarden to Shotton.
The designers of the new bridge were the Flintshire county surveyor R.G. Whitley and Basil Mott (1859-1938, created baronet 1930) of consultant Mott, Hay and Anderson. Whitley acted as resident engineer and H.F. Molony assistant resident engineer. The contractor was moving-bridge construction specialist Sir William Arrol & Co Ltd, under chief engineer and director Adam Hunter (1809-1898) with E. Boynton as agent and H.P. Forge in charge of work on site. Construction commenced in February 1925.
The three-span bridge crosses the river at a slight skew. It measures 121.2m between low concrete block abutments. The abutments sit on concrete foundations carried on square section precast reinforced concrete piles. The two river piers are each founded on two 4.9m diameter steel cylinders sunk through sand and ballast strata into the underlying clay. Above the river bed, the cylinder pairs are braced laterally with a panel of diagonal and horizontal struts.
The bridge's central lifting span measures 40.8m between pier centrelines. The fixed side spans are 40.5m from abutments to the pier centrelines. The deck carries a 6.1m wide roadway flanked by 1.8m wide footways edged with plain steel railings.
The superstructure is of riveted steel and consists of main (longitudinal) girder trusses to the sides and below the deck, with cross (transverse) plated girders below-deck, and lattice cross beams and bracing connecting the tops of the trusses. The vertical trusses are composed of I-section members, and set at 8.4m centres, running along the bridge between the roadway and the footways. The footways are supported on curved beams and pass under archways joined to the opening mechanism.
The opening mechanism consists of two Scherzer rolling-lift leaves, cantilevering from the piers to mid span and rolling on cogged tracks (like a rocking horse) through an angle of 79.5 degrees, making a clear opening of 36.6m. Each leaf lifts from mid span as the curved rolling section rotates onto its heels about the main pinion, and is held aloft by a counterweight a steel ballast box of gross volume 121.7 cu m, half filled with concrete kentledge.
The three cross girders nearest the piers support the track girders and carry the weight of the opening leaves an arrangement unique to Britain. The end cross girder is directly over a pier and so not subject to vertical movement. The other two cross girders deflect with the fixed spans, altering the level of the track girders, which are not supported in the usual rigid way, resulting in a certain economy of foundation construction. The three cross girders are set at 3.9m centres and the girder over the piers is 864mm deep.
The main girders have an effective depth of 4.7m at the centre of the bridge and 8.3m over the pinions. The booms are formed in 381mm by 102mm channels, the bottom booms sloping at 1 in 30, the same as the roadway. Originally, the roadway and footway surfaces were of timber and the bridge was operated electrically.
The bridge was opened on 24th November 1926 by Minister of Transport Colonel Wilfred Ashley (1867-1939, 1st Baron Mount Temple 1932), though not fully completed until May 1927 (which is presumably when the Victorian bridge was demolished). The snecked stone abutments of the old bridge are still visible on the west side of the new one. The total cost of the works, including demolition, was 81,551 or 83,051 (sources vary).
After 1945, car ownership became more widespread and fewer vessels travelled upriver from Shotton. The lifting machinery was used regularly until the 1950s but subsequently was test lifted only once a month. By 1960, the mechanism was inoperable. In 1966, the two lifting leaves were bolted together to fix the central span. Wedges were inserted under the rolling sections to stop them moving. The driving engines and control house were removed and the timber deck replaced in reinforced concrete.
In 1960-2, a new three span bridge of reinforced concrete was constructed about 170m upstream of the bascule bridge to take the main road (A494). Navigational access for tall ships was not needed upstream of Shotton so this bridge does not have a lifting mechanism, though its central span was constructed in a way that makes it capable of being lifted.
In May 2005, Queensferry Rolling-lift Bridge was Grade II listed (number 85251, listing amended August 2005) for its "technical interest as a rare surviving example of a bascule bridge, retaining its architectural character and detail".
Resident engineer: R.G. Whitely
Assistant resident engineer: H.F. Molony
Contractor: Sir William Arrol & Co Ltd
Research: ECPK
bibliography
http://happypontist.blogspot.com
https://coflein.gov.uk
https://gov.wales
https://historypoints.org
www.deeside.com
www.gracesguide.co.uk
www.ice.org.uk
www.movablebridges.org.uk
Location

Queensferry Rolling-lift Bridge (Jubilee Bridge)