Victoria Swing Bridge, Aberdeen

One of the hydraulic pumps, and the gas engine, on display at the Scottish Maritime Museum, Irvine, 2022

No longer extant.

See here for a photograph of the first swing bridge at the entrance to Victoria Dock, Aberdeen. It was a twin leaf cast iron bridge, and was replaced by a steel girder bridge, completed in 1904.

August 1904 Report

'ABERDEEN HARBOUR INSPECTION. .... Passing along the bridge, the party entered the pump-house and saw the large pumps which compress the water to 1000 lbs. to the square inch. One of these pumps is driven by a 45 horse-power electric motor, and the other pump is driven a gas engine of 54 horse-power. The latter engine has been supplied in case of breakdown of the electric supply, which would prove a very serious matter if a ship happened to be passing through the bridge. Beneath the pump-house floor is a large pipe chamber, where the whole of the complicated system of piping is laid down, making it easy of access for repairs or renewals. From this underground chamber a tunnel is bored right through below the bridge itself, whereby access is possible from the pump-house to the machinery under the bridge. The commissioners then made an inspection of the machinery for lifting and turning the bridge, which is fitted up in a huge masonry pit underneath the bridge. Underneath the centre of the bridge was seen a large pivot on which the bridge will revolve. It consists of a large steel press on which the pivot of the bridge is fixed, so that when the bridge is revolving, it is really supported by water. The weight the weight of the bridge when being turned and supported is about 700 tons. In case of a breakdown of the centre press, two smaller side presses, combined of equal power to the centre press, are provided. For turning the bridge, two large hydraulic engines, right and left hand, are connected, and the turning is effected without the intervention of gear or chains, as the connecting rods of the hydraulic turning engines are attached directly to the underside the bridge, and act exactly similar the human arm in opening and shutting a door. The whole of the complicated actions necessary for the lifting and turning the bridge are controlled from a high level cabin, and they are directed by an operator by means of two simple levers. The comissioners then proceeded ....'

December 1904 Report

'THE NEW REGENT BRIDGE, ABERDEEN. The opening to-day of the new Regent Bridge to shipping, and railway and street traffic, marks an important stage in the history of the port of Aberdeen, as it celebrates the completion of the first and most-needed part of the work of remodelling the existing dock system to bring it to the requirements of modern commerce. In deciding to carry out this work, the Harbour Board were fully aware of the many difficulties to be faced — difficulties such as could hardly be found at any other part of the docks, as, in the work of reconstruction, the shipping traffic could not be suspended or even disturbed; the railway, vehicular, and pedestrian traffics had to be carried on without interruption; a new passage for shipping had to be constructed before it could be diverted from the old entrance and the old bridge and piers removed; and the space available for carrying out reconstruction operations was of the most limited nature, as the berths and quays in the vicinity had to be strictly conserved to trade. The work was thus naturally diifficult and tedious of execution, and the cost great; and the Harbour Commissioners are to be congratulated to-day on the successful accomplishment of this the most formidable part of their progressive scheme of dock reconstruction, and its fitness to meet not only present but also future requirements, as the less often such work has to be done in the midst of established traffics the better for the port and all its interests.

'THE OLD REGENT BRIDGE AND ENTRANCE. It is 72 years since the old "drawbrig" was constructed, at which time the Commissioners, under the Harbour Act of 1829, were directing their attention to the training of the river Dee into a definite channel, clear of the site of the existing docks, by embanking the Inches. The large tract of ground reclaimed by these operations was opened up to the harbour and city by a swing bridge at the foot of Marischal Street, which the new Regent Bridge now replaces, the cost of the works being about £82,000. The old Regent Bridge was constructed in two halves with cast-iron girders, on which was laid a timber platform to carry the roadway; and each half was swung, means of hand gearing, upon a roller turntable resting on a masonry pier at each side of the entrance. The width of the opening was 48 feet, and through this opening the shipping passed to what is now the Upper Dock; but, as the foundations these piers were laid at a depth of only 16 feet below high-water level, it would appear that the conversion of the then tidal harbour into wet docks with gates to accommodate large ships was never contemplated. The expansion of trade at Aberdeen Harbour and the introduction of steamships have long ago condemned the old bridge as a relic of an age venerable, but no longer useful, although it was justly considered then as engineering feat of most creditable skill. To give a concise idea of the relative proportions of the old and new bridges, the following comparative dimensions and features are tabulated: [table of dimensions and weights] .... New Bridge — Heaviest locomotives and trains on both railway lines at same time, with vehicles and dense crowd of people occupying all other spare space. Although the foundations the old bridge were laid at depth of 16 feet below high water, the increase in size of ships frequenting the Upper Dock imperatively demanded more depth in the passage, and its was eventually six feet lower in the centre, giving 22 depth feet at high water. .... [Details of construction] ....

'THE SWING BRIDGE. Pivoting on the south abutment is the swing bridge itself, a steel structure of imposing dimensions. It has a total length of 156 feet, and a total width of 45 feet, or 5 feet wider than Marischal Street; and it weighs nearly 700 tons when swinging. This enormous weight is carried on a large steel pivot resting on a hydraulic press, so that the great mass swings round on a water cushion which is practically frictionless. The pivot is not, however, placed exactly in the centre of the bridge, but at a point about two-thirds along its length, making a long and a short arm, and, of course, throwing the bridge out of balance, so that a weight about 140 tons of iron blocks has to be placed at the short arm to make the bridge level. The object of thus designing the bridge is to save space, the short arm does not require to go so far back into the street, and much less masonry is required, the cost of which is much in excess of rough cast iron. In the case of Regent Bridge, had the arms been made of equal length, it would have been impossible to get any railway curves laid at the south side, because, even as it is, the space is limited to an undesirable degree. The large girders of the bridge are of what is known as the "bowstring" type, being curved on the top, and they measure 20 feet deep over the pivot, which is at the deepest part. The roadway carries two lines railway for up and down, traffic, two tracks for vehicular traffic wide enough to admit traction engines, and the side walks for foot passengers are placed outside the main girders on brackets, and are fenced off by steel lattice-work parapets. The bridge is built of the finest mild steel, and has been designed to carry the heaviest locomotives and trains on both lines of rails at one time, along with any vehicles and as many people as can find standing space, or a dense crowd of people and vehicles all over the bridge. This was necessary on account of the great weights to which locomotives are progressing, so that the steelwork may not be unduly strained in a few years. The deck of the bridge is neatly paved with timber causeway setts, to reduce the weight to be lifted and swung by the machinery.

'THE MACHINERY. Although to the casual observer the large girders may seem to represent the complete bridge, yet another and even more imposing feature is the powerful hydraulic machinery for lifting and swinging the structure — machinery that lies concealed under the bridge itself, in a huge pit far below the level of the water in the dock, but to which access is readily got by stone steps and passages in the masonry. The visitor to this underground chamber would probably be impressed first with the huge central hydraulic press and pivot by which the bridge is lifted bodily off its rests a distance of 5 inches before being revolved. This hydraulic press consists of a massive cast-steel cylinder, about 7 1/2 feet high and 5 feet outside diameter, capable of working with a water pressure of 1000 lbs. per square inch, developing a total lifting power of over 750 tons. On the top of the piston or ram of this cylinder rests the large steel ball pivot, through which the weight of the whole bridge is transmitted to the water. Alongside the centre hydraulic press are two smaller presses of the same type — one either side — the tops of which form parts of a steel roller path, on which rest large steel rollers placed under the bridge. This arrangement is in case of the large central cylinder being disabled, when the two smaller presses — which are together of equal power to that of the centre press — are brought into action, lifting the bridge and forming a complete turntable with the roller path, on which the bridge is then revolved. The turning or slewing of the bridge is accomplished by two powerful hydraulic engines, which may be seen on the right- and left-hand sides of the bridge. The great feature of these powerful engines is their simplicity, as no wheels, chains, or gear of any kind is be found, about them — they simply lay hold of the underside of the bridge, each with a massive steel arm or connecting rod, and revolve it, in exactly the same way as a human arm opens or shuts a door. Should these engines break down the other alone is able to the revolve bridge; and an arrangement of design enables each to work at half power only when in combination. The pump house is situated in the block of building on the south abutment, and there water pressure is generated for operating the bridge by pumps at 1000 lbs. per square inch. The pressure water is stored in a large accumulator or reservoir situated in the tower at the northwest end, and sufficient water can be stored to enable the bridge to be swung and retby a gas engine — as a safeguard against a complete failure of either source of power. It may be a matter for surprise to state that the whole of the machinery and the swing bridge are under the control of only two levers situated in a high glass cabin placed on the north-east corner of the building, and that these levers are automatically locked by the bridge itself, so that only one operation — either that of lifting or that of swinging — can be done at a time.

'THE APPROACHES AND RAILWAYS. The approaches the bridge are laid out with steel lattice parapets and fine dressed granite pilasters. .... THE TEMPORARY BRIDGE ....

'THE ADMINISTRATION OF THE WORKS. The whole of the works have been designed and carried out by administration entirely from the Engineer's head office. The responsibilities of a contractor were thus added to the work of design and supervision, and a large amount of detail had be most carefully drawn out, as the drawings were strictly worked to when issued. The design of stagings, the arangement of plant, the design and construction coffierdams, the details of pier foundations, masonry, and such like matters, along with the ordering of the materials required, formed some of the work which fell to the Engineering Staff, in addition to the duties of design, direction, and supervision. The whole of the masonry stones were carefully drawn out first, and dimensioned before being ordered, and, when necessary, were even drawn out full size on the floor before templates were sent to the quarry. Much credit is due to the engineers for the successful manner in which the works have been completed — to Henry H. Wake, M. Inst. C.E., the Consulting Engineer; Mr R. Gordon Nicol, M.Inst.C.E., the Engineer-in-Chief; Mr Wiliiam Simpson, Assoc. M. Inst.C.E., the Executive Engineer; Messrs Barr, Blackadder, and Diack, Assistant Engineers, and the other members of the Engineering Staff; also to Mr H. Munro and Mr W. Panton, who have had the supervision of the Commissioners' workmen, and to the various inspectors and foremen, who have all contributed to the successful issue of a complicated piece of engineering work. Messrs Sir William Arrol and Company, Ltd., Glasgow, have built the steelwork of the bridge in a manner in keeping with their great reputation as bridge-builders; and Messrs Glenfield and Kennedy, Ltd., Kilmarnock, have likewise fully Maintained their good name as makers of hydraulic machinery of the very best kind. The granite stones were supplied by John Fyfe, and were of a quality and finish equal to any found in similar engineering works in the country. The railway work was by Messrs Hadfield's Steel Foundry, Company, Limited, Sheffield, in a most excellent manner; and the platelaying and causeway work by Mr Peter Tawse, Aberdeen, who has successfully accomplished a difficult job with his accustomed energy. ....'

29 December 1904

Bridge opening ceremony. The Aberdeen Press and Journal devoted many column inches to the event.

1925 'Power for Dock Gates. The demolition the Graving Dock involves the removal of the engine-house and the discontinuance of the hydraulic pump and accumulator from which are operated the entrance gates at the south entrance to the Victoria Dock, the swing bridges over the south entrance and over the lock entrance and several capstans in the vicinity of the entrance. In 1919 the Commissioners authorised the provision of a new pumping set, electrically driven, and the re-erection the present accumulator on a site within the harbour workshops at an estimated cost ef £4660, but, Mr R. Gordon Nicol, harbour engineer, now recommended, and the Works Committee approved, of an arrangement by laying hydraulic pipes from the existing hydraulic installation used in connection with Regent Bridge, the pipes being laid along Blaikie's Quay to connect with the existing hydraulic pipes at the dock gates. The cost is estimated by Mr Nicol at £1910, and Messrs. Glenfield and Kennedy, Ltd., Kilmarnock, have offered to supply pipes at £1280, and quoted weekly rates for skilled men for the work, which is expected to occupy from eight to 10 weeks. The proposal was adopted.'

1928 'The harbour engineer reports that the two electric motors for working the swing bridge over the south entrance to Victoria Dock have been installed. The new system of operating the swing bridges had been working satisfactorily, and arrangements had been made to discontinue the hydraulic power installation at the old graving dock engine house.'

1974 The bridge was still operated a few times per day, still using the old DC motors and switchgear, with the gas engine still available as backup, but the machinery was looking neglected. . There were hopes that some of the equipment would be preserved, and indeed it was: the gas engine and one of the hydraulic pumps are on display at the Scottish Maritime Museum, Irvine.

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