Putney Bridge
The Metropolitan Board of Works purchased the old wooden bridge in 1879, discontinued the tolls in 1880, and set about its replacement.
The new bridge was a short distance upstream of the old, and its route followed the line of an iron aqueduct supported by eight piers in the river. See 'Fig. 4' above). A temporary aqueduct was built alongside the old bridge, to serve until pipes were laid in the new bridge, each side of the bridge having two 24-inch and one 12-inch pipe, laid in sand and covered by York flagstones. 'The bridge is entirely constructed of granite ; for the voussoirs of arches, the piers, and spandrels white granite selected from some forty Cornish quarries is being used ; but the parapets will be of rose-tinted Aberdeen granite, following the same disposition of materials as may be seen at Waterloo Bridge, where the main body of the work is of Cornish and the parapets and balustrading of Aberdeen granite. .... The excavations for the abutments were most troublesome on the Middlesex side, where they have been taken to a depth of 28ft, below datum line, and rest on a bed of concrete, great precautions being taken to prevent sliding of the mass. On the Surrey side the abutments are only taken to a depth of 10ft. below datum, the foundation being better. .... All concrete throughout the bridge is of 6 lime to 1 of Portland cement, or 8 ballast to 1 of Portland cement, and the latter material is tested by Adie's apparatus to a tensile strain of 170lb. per sq. in. after 28 days. The lower caisson has a cutting edge at the foot, and having been lowered from piles by screws, the soil was excavated from within the caisson to an average depth of 25ft. below the river bed. A firm basis being reached at this level, the cutting edge was underpinned with Bramley Fall masonry, resting on a bed of concrete interposed between the stones and the river clay. .... The whole of the five arches are being turned simultaneously, wrought-iron ribs, nine to each arch, and spaced 5ft. 8in. apart, from centre to centre, being employed as supports. These iron girders are in turn carried on timber piles, so arranged as to leave for navigation openings varying from 30ft. in central span. The granite voussoirs range in length from 4ft. 4in., in the centre of span, to 5ft. 4in., and all stones are separated from each other by two vertical strips of 3/16 in. lead, going the full depth of the stones, and these joints are filled in behind the lead strips with grouting composed of one of Portland cement to one of Thames sand. ...'[1]
Aspects of the design and construction were described and illustrated in Engineering 1886/07/23, from which several drawings are included here. Fig. 4 shows the chambers within the bridge structure, and the concrete-filled caissons.
See here for photographs showing the old bridge, the old aqueduct, the temporary aqueduct, and the new bridge during construction [2]
The new bridge was designed by civil engineer Sir Joseph Bazalgette as a five-span structure, built of stone, concrete, and Cornish granite. The work was carried out under the superintendence of Edward Bazalgette. Spans of the five arches: 112 ft., 129 ft., 144ft., 129 ft., and 112 ft. To construct each pier, three double-walled wrought iron caissons were sunk through soft clay, and then into hard clay. The cavity was filled with concrete to add weight during sinking. After underpinning the caissons with stone bloks set on concrete, the central cavity was filled with concrete, and brick footing was laid on top.
The bridge was constructed by John Waddell of Edinburgh, whose tender of £240,433 was accepted on 15 April 1882. It is 700 ft long and 43 ft wide, and was opened by the Prince (later King Edward VII) and Princess of Wales on 29 May 1886.
1886 The new stone bridge was opened and still stands today.
From the London Evening Standard, 31 May 1886: 'It is scarcely necessary to say that in a work of this kind the sufficiency of the foundation and the maintenance of the true form of the arch are all-important. The former has been secured by carrying the foundations well down into the London clay, to an average depth of 24 feet below the bed of the river, so that any disturbance from the action of the stream is practically out of the question. To get in the foundations a timber dam of piles was driven down to a depth of 37 feet below high water mark, enclosing a space around the site of each pier. After the water had been pumped out of this enclosure, wrought iron caissons were built up within the dam, and sunk down to the intended depth of the pier foundations. Each caisson was formed with a double skin of wrought iron, with a space of three feet six inches between them, and this was filled with concrete before they were lowered. Three of these caissons were sunk under each pier. The spaces left within them were excavated, and after the caissons had been sunk to the required depth they were filled with concrete, upon which the masonry of the piers was built. In order to obtain as great a headway as possible for navigation during the construction of the bridge, the centres for supporting the arch stones were made of wrought iron, and these were made rigid, so as to prevent distortion during the laying of the arch stones. When, however, the centres were struck, the maximum depression of the large centre arch was only about one inch, which had been anticipated and for which allowance had been made. The entire structure, which was designed by Sir J. W. Bazalgette engineer to the Board of Works, and Mr. E. Bazalgette, assistant engineer, is of granite, of which over 300,000 cubic feet have been used, the stone being obtained from Cornwall and Aberdeen. To give a clearer idea of the alterations which have been made in the approaches it may be mentioned that a new rising approach has been formed from High-street, Fulham, at its junction with Church-street, partly through the gardens of the vicarage, and close to Fulham Church, the total length being 210 feet, its width 50 feet, and its gradient 1 in 35. On the Putney side a new road has been formed in a direct line from Putney High-street in lieu of the narrow and circuitous approach to the old bridge, and it has a length of 150 yards, with a width varying from 52 to 70 feet. The construction of the work has effected a double improvement. Previously the site was occupied by the unsightly aqueduct of the Chelsea Water Works Company, which was replaced by a temporary aqueduct, which, with the old bridge, will shortly disappear, the mains being now laid under the footways of the new bridge. The contract for the whole of the permanent works was let to Mr. Waddell in April, 1882, for the sum of 240.,000 l, and the time occupied in the construction of the bridge has been a little under four years. .....'.
For detailed specifications, see The Engineer 1882/10/20, The Engineer 1882/10/27 (also included structural details of iron caissons), and The Engineer 1882/11/10.