Crosses the River Thames between Chelsea and Battersea.
There have been two suspension bridges here, and a temporary steel and timber bridge built during the Second World War.
First Bridge (1858 - 1935)
Engineer Thomas Page was appointed to build the bridge, and presented several potential designs, including a seven-span stone bridge, a five-span cast iron arch bridge, and a suspension bridge.
1851 The Commission selected the suspension bridge design, and work began in 1851 on the new bridge, to be called the Victoria Bridge.
Page's design was typical of suspension bridges of the period, and consisted of a wrought iron deck and four 97-foot cast iron towers supporting chains, which in turn supported the weight of the deck. The towers passed through the deck, meaning that between the towers the road was 7 feet narrower than on the rest of the bridge.
The abutments were of brickwork and concrete and their riverside portions were carried on timber piles enclosed in a casing of cast-iron cylinders and plates. On this casing, concrete and York landings were laid to form a foundation for the brick-and-stone foundations of the low towers and saddles over which the suspension chains were led. The chain tunnels were of brickwork enclosed in concrete and descended at an angle of 155 deg. to the mass of brickwork forming the anchorage. The piers, which were also supported on timber piles. enclosed in cast-iron piles and plates, consisted of concrete and York landings on which cast-iron shells 32 ft. high and 1 in. thick, lined with brickwork, were built to the roadway level. Above those shells were a series of cast-iron columns, which formed the towers for carrying the chains. These columns rose to a height of 57 ft. above high water and at the top were con nected by a flat bedplate carrying steel rollers. On these roliers was a saddle consisting of a slotted cast- iron plate. Originally there were two wrought-iron chains on each side of the bridge, but a third was added in 1863. Longitudinal lattice girders supporting the roadway were hung to the chains by 2-in. rods, and to these girders transverse plate beams were secured. The roadway, which was 29 ft. 4 in. wide, was laid over these plates and a series of longitudinal beams'. The footways were carried on cantilever brackets.[1]
The suspension chains were made by Howard, Ravenhill and Co of Rotherhithe.[2]
Although work had begun in 1851 delays in the closure of the Chelsea Waterworks, which only completed its relocation to Seething Wells in 1856, caused lengthy delays to the project, and the ironwork from C. D. Young and Co was only transported to the site in 1856.
Queen Victoria formally opened the bridge on 31 March 1858, naming it the Victoria Bridge. It proved popular for visits to Battersea Park. Shortly afterwards, concerns were raised about the bridge's safety. Following an inspection by John Hawkshaw and Edwin Clark in 1861, an additional support chain was added on each side. Despite the strengthening, a weight limit of 5 tons was imposed, and the name was changed from Victoria Bridge to Chelsea Bridge.
Second Bridge (opened in 1937)
The old bridge had a carriageway width of only 29ft. 4in., further constricted to 22 ft 5in at the towers. The load restriction of 5 tons meant that it could not be used by buses or heavy lorries, with the result that congestion was caused on Vauxhall Bridge, downstream, and to a lesser extent on the Albert Bridge.
c.1937 A new, much wider bridge was constructed to replace the previous bridge. Messrs Rendel, Palmer and Tritton were the consulting engineers; Holloway Brothers (London) were the contractors. The steelwork was supplied by the Furness Shipbuilding Co of Haverton-on-Tees. The steel cables were supplied by Wrights' Ropes Ltd of Birmingham.
It is the only self-anchored suspension bridge carrying road traffic in the UK. It is also unusual in having hinged towers, and in not having the left and right hand towers connected above the deck.
Its utilitarian appearance is in stark contrast to its predecessor. While it is not the most attractive Thames bridge, it is one of the most interesting, structurally.
The very extensive use of rivets, and the design of the lamps, are perhaps the only indications that this is not a modern bridge.
The following is condensed from an article in The Engineer in 1936[3]:-
Conventional land anchorages are unnecessary as the suspension cables are secured into the ends of the stiffening girders which support the deck of the bridge. These stiffening girders are thereby put under compression. The four towers are separate from one another and are mounted on pin bearings [rocker bearings?] on the piers. Lateral stability is provided by smaller pin bearings on each side. The suspension cable is fixed at the tops of the towers and is not mounted on rolling or sliding bearings. Expansion or contraction of the cables is accommodated by slight tilting of the towers on the pin bearings. The cables at each end are anchored into fan-shaped enlargements on the stiffening girders (Fig 1937. 5). The latter are restrained at the abutments by vertical links which allow horizontal, but not vertical, motion to take place. Most of the load of the bridge is taken by the towers and transmitted by them to the piers. On the north side the stiffening girders are pinned to the towers (see Fig. 1937. 4). But on the south to allow for expansion, there is a hinged joint allowing for horizontal, but not vertical, motion (visible in Fig. 5 of 1937. 2). Each stiffening girder has two pin joints disposed respectively just on the river side of each pier (Fig. 1937. 3). For erection purposes only there was also another pin joint at the centre of the span, (Fig. 1937. 7) but it was riveted up later.
The suspension cables each consist of 37 steel wire ropes, 1 7/8" diameter, assembled together in a hexagonal bundle. At the anchorages each rope is separately attached to the fan-shaped housings (Figs. 1937. 5 & 6). The box section stiffening girders are made of high-tensile structural steel.
The piers were constructed in open cofferdams, taking advantage of the availability of interlocking sheet steel piling. The timber piles of the old piers which were cut off as excavation proceeded showed no signs of deterioration. The bases of the new piers were founded on hard London clay at 40ft. below O.D. Mass concrete was deposited directly on the clay to a thickness of about 18ft. over the whole area within the coffer dam. The lower portions of the cofferdams were left in situ. On the block of concrete the central core of each pier was built up and faced with Cornish granite. A large void was left in each pier between the tower bearings in order to save weight and cost. Coffer dams were also used for constructing the abutments. The abutments appear heavier than they actually are, and are largely hollow, as they are lightly-loaded.
Contrary to normal practice with suspension bridges, the stiffening beam had to be erected before the cables could be anchored. Temporary steelwork was used, and the stiffening girders, together with cross girders and stringers, were erected in four sections successively. As each section was completed four barges, each of 120 tons capacity, provided with timber cribbing, were drawn into position beneath the service girder. Then the rising tide lifted the latter off its supports and the barges were warped clear of the stages and towed by tugs across the river. See 1936 illustrations. Temporary piled stagings had been built to receive the sections of the stiffening girder structure.
Since the towers are supported on pin bearings they could not maintain themselves upright until the cables had been slung, so they were temporarily guyed to the stiffening girders. In order to ensure that the bridge would assume its correct outline under full dead load, each rope was marked to length under a load which would produce the same aggregate extension as the dead load stress in the completed structure.
Further information, from The Engineer in 1937 [4]:-
A new technique was required for making the wire ropes. It was necessary that the ropes composing the cables should have a constant modulus in the load range, all irregular stretch being taken out after fabrication by "pre-stressing," stretching the cables in a straight line under a load sufficient to achieve this object . It was also required that, whilst the ropes were under stress, the load should be adjusted to a figure corresponding to the designed full dead load stress on the cables when in position on the bridge, so that the ropes could be marked to correct length and with positions of sockets, saddles, turning points, and cable clips, in accordance with the designed outline of the bridge. For this purpose, a special pre-stressing plant was installed at the works of the manufacturers. It consisted of a hydraulically operated Avery testing machine mounted on a heavy concrete foundation, and 1000ft. away in a horizontal straight line, an anchorage end of suitable steelwork, also mounted on a heavy foundaton block, both foundations be ing designed to withstand a pull of 100 tons without movement. A greased wooden testing track, raised 27in. from the ground, was provided to afford support to the rope throughout its length Alongside the track was a duct containing a calibrated steel tape in one piece, 810ft. long. The tape was calibrated for a standard temperature and pull, and was provided with a gravity-operated tension device.
The ropes consisted of 74 lengths, each of about 800ft., approximately. 2in. diameter, of locked coil construction, and having a breaking load of 190 tons. After manufacture each rope was fitted with one permanent adjustable socket and one temporary socket, the overall length being made slightly longer than the finished length to permit final resocketting after pre-stressing and marking. Measurements of stretch were read on a brass vernier scale located at a slider bed at the coupling point between the master rope and the rope under test. The load was read on a calibrated pressure gauge on the testing machine, and continuously checked by a carefully calibrated bar dynamometer of 100 tons capacity mounted in the line of pull at the slider bed. A system of headphones from the testing machine to every point throughout the pre-stressing track, maintained constant communication between machine operator, the marker on the rope, and the operator observing the vernier and bar dynamometer readings, and a system of buzzer signals for marking at given loads was also used. During the operationg, the rope was held at a load corresponding to its maximum working load in the bridge for periods of one hour, until all permanent set was eliminated , after which the rope was marked at the various points under a load corresponding to the dead load of the bridge. Marking was carried out in such a way that friction effects were eliminated and temperature effects were avoided by marking only when the temperatures of the tape and rope were almost identical. These temperatures were carefully followed by plotting graphs of the rope temperature, as obtained from thermometers inset in sample pieces of rope, and also of the air temperature throughout each day.
As each rope was erected on the bridge its ends were drawn over the turning point castings located within the stiffening girders above the vertical anchorage links and attached separately to the fan-shaped ends of the stiffening girder by the insertion of split spherical seatings under the sockets. Each rope was provided with a screwed socket arrangement shown in Figs. 1937 5 & 6. The ends of the ropes are secured in the conical portion of the sockets in the usual manner by unlaying the wires, 'brooming' or doubling them over and afterwards drawing back into the cone and running solid with white metal. The screwed portion provided for adjustment of length at site if found necessary, but, nevertheless, all sockets were fixed by Wrights' Ropes to the correct length as marked during the pre-tressing operation.
When the assembly of the ropes was completed, the caps were bolted down on the tower top castings. All was then in readiness for the attachment and connection of the hanger rods. The first operation was that of jacking up the centre of the main span - Fig. 1937. 7 - an action rendered possible by the provision of the temporary hinge or pin joint at this point. The towers were also tilted back towards the shores so that the cable, being thereby slackened, it was possible to connect up the shore span hanger rods to the stiffening girders. By adjustment of the jacking under the main span it was next possible to connect the hangers at the ends of this span, and as the jacks were progressively slacked away to connect the remaining hangers as they came into position. The towers then being supported by the cables, the guy ropes were removed, and the centre of the bridge lowered by successive removal of packings at the temporary mid-span support until the weight of the bridge was carried on the hanger rods and cables. The centre hinges in the stiffening girders were not finally riveted up until the bridge had assuned its dead load profile.
Additional information from 'Engineering'[5]:-
The resident engineer was Duncan Kennedy, M.Inst.C.E.
The overall length between abutments at + 18 O.D. is 698 ft., and its overall width 83 ft. It carries a 40-ft. carriageway for four lines of traffic and two footways with a minimum width of 12 ft. at the towers and 13 ft. 11 in. elsewhere. As on the old bridge, these footways are supported on cantilever brackets. The clear waterway of the centre span is 332 ft. and of the side spans 153 ft.
Fig. 1937 8 shows the south (Battersea) end of the bridge, clearly showing the fanned-out end of the stiffening girder and also the adjacent link-support which provides vertical constraint and some support, while accommodating expansion, similar to the arrangement at the southern tower. The northern tower has a pinned joint without a link, while the north shore (Chelsea) end of the girder presumably has the same type of link as at the south shore.
Fig 1937 9 shows the box girders passing through openings in the towers. It also shows how each tower is splayed out and provided with pin bearings for stability, noting that the towers are not joined together at the top.
The box girders are partially open at the bottom - see Fig 2023 10. They taper out to become wider at the fan portion, as seen in Figs 2023 10 and 3.
Regarding the cables: 'Each rope was then lifted by two cranes into the grooved castings which are fixed to the tops of the towers, adjusted to its correct position, and the socketed ends drawn into the ends of the stiffening girder over the turning point castings. These castings are located in the girders over the anchorage links. The ropes were finally secured to the four ends of the girder by the insertion of split spherical socket seatings. The cable clips and hanger rods were next assembled, the towers being canted towards the abutments to permit the shore span hanger rods to be attached to the stiffening girders. The centre joint of the main span was jacked up sufficiently to allow the operation to be effected over the main span. This joint was gradually lowered on the jacks and each hanger rod connected as it came into position, working from the towers towards the centre. When all the hanger rods had been attached, the temporary centre support was removed, so that the load was carried by the cables.'
Newspaper Reports
1934 'ORDER FOR TEESSIDE. BRIDGE SUB-CONTRACT THAT WILL INVOLVE 3,000 TONS OF STEEL. From Our Own Correspondent.
MIDDLESBROUGH, Tuesday. The sub-contract for the fabrication of the steelwork for the new Chelsea Bridge, obtained by the Furness Shipbuilding Company, Ltd., of Haverton Hill, involves approximately 3,000 tons of steel, and is of particular interest owing the fact that the firm are primarily shipbuilders.
The bridge, which a suspension type structure, is to be erected within three years. A temporary structure first has to be built, after which the existing bridge will be demolished. It is anticipated that about a year will elapse before the erection of the steelwork of the new bridge is begun. It is understood the steel will be supplied to the fabricators by the South Durham Steel and Iron Company, or the Cargo Fleet Iron Company, which is under the same control.'[6]
Footbridge
In 2004 a curved footbridge was built below the southern end of Chelsea Bridge, carrying the Thames Path to link the new developments around Battersea Power Station to Battersea Park.
See Also
Sources of Information
- ↑ Engineering 1937/05/07
- ↑ The Engineer, 2 January 1863
- ↑ The Engineer 1936/08/07
- ↑ The Engineer 1937/05/07
- ↑ Engineering 1937/05/07
- ↑ Leeds Mercury - Wednesday 24 October 1934
- [1] Wikipedia