Barnes Bridge
There are two immediately adjacent bridges here.
The original cast iron arch bridge was built for the L&SWR in 1849, and is now disused.
The old bridge carried only two tracks, and needed to be widened, and partly due to concerns about the safety of cast iron bridges for railway service, a replacement bridge for four tracks was constructed alongside in 1895. Fortunately, from the point of view of industrial heritage, the upstream half of the old bridge, and the ribs of half the downstream section, were retained. The 1849 and 1895 bridges can be seen in Figs. 3 & 4.
Much of the following information is taken from a description of the old and new bridges in Engineering in 1895 [1]
The 1849 Bridge
Designer: Joseph Locke. The ironwork was produced by Fox, Henderson and Co. Three 120ft spans, originally with two pairs of cast iron arch ribs, 2" thick, 3ft deep, with flanges 12" wide. The ribs were cast in four segments, the two middle segments having a portion of the horizontal girder cast in the same piece (see Fig. 5). Each pair of ribs was well tied together through the webs, with bolts and distance-pieces, and diagonal bracing was added in about 1882, having wrought T-irons riveted back to back (see Fig. 10).
On the inner two ribs, the bolted joints (Figs. 6 & 8) have flanges on both sides, whereas the outer rib has only one flange on the inside, presumably to give a neater appearance. Unusually, the vertical flanges do not extend the full depth of the beams. Fig. 7 shows the outer face of the outer rib, with its not-quite-invisible joint.
From this joint towards the piers or abutments the rib and horizontal girder are separate castings connected by the spandril fillings which are bolted to the extrados of the rib and to the underside of the horizontal girder.
Commencing from the centre of the span at the bottom flange of the rib there is a horizontal ledge 4 in. wide and 2 in. thick, cast on to carry the timber cross-bearers; this projection reaches to the joint at 30 ft. from the centre; beyond that distance the bottom flange of the horizontal girder is used to carry the ends of the bearers (see Fig. 10). On the outer ribs the top flange of the horizontal girder is 10" wide, to allow for a light cast-iron cornice moulding and parapet to be bolted on, and junction of the web and flanges features a fillet moulding to improve the appearance. These features are visible in Fig. 7.
In Fig. 9, to the right of the dove, can be see one of the clamps which tie the pairs of inner ribs together.
The timber cross-bearers were 12" deep, 6" wide, and pitched 2 ft. apart between centres ; the rails and chairs were carried on longitudinal baulks 16" by 11" and between these baulks the bridge was decked with 3" timber.
Fig. 11 shows a turnstile which has survived on the Chiswick side of the 1849 bridge.
The 1895 Bridge
The replacement bridge was designed by Edward Andrews of the L&SWR. The general builders’ work was let to Perry and Co., of Tredegar Works, Bow. The ironwork contractors were Head, Wrightson and Co. This bridge has three spans of wrought iron bow string girders. From the outset a pedestrian walkway was cantilevered from the bridge on the downstream side.
Both the abutments were extended using a timber cofferdam. For the piers, wrought-iron caissons 28 ft. long and 18 ft. wide was built. The lower length of the caisson which remained permanently in the bed of the river is 16 ft. deep, including a steel plate with cutting edge at bottom, riveted to the lower edge of the this lower caisson. The caisson were riveted up on staging erected in the river, and as they were sunk additional lengths were bolted on, the joints being made water-tight with india-rubber packing. Although these caissons were designed so that they could be sunk under pneumatic pressure if necessary, it was found, as the work proceeded, that this was not required, for, being weighted by some of the permanent concrete filling on the top of the ceiling plates, the caissons soon sealed themselves in the London clay ; the water was then removed by pumping, and the clay dug out and hauled up in buckets until a depth of 35 ft. below Trinity high-water mark was reached, the Thames Conservancy Board having power to dredge the river to a depth of 23 ft. below Trinity high-water mark. The permanent caisson was then filled with concrete in Portland cement for a depth of 14 ft. 6 in., the remaining 1 ft. 6 in. being filled up with brickwork in Portland cement ; above this the brickwork in Portland cement for the pier is carried up to 2 ft. 6 in. above low water, being faced with Stafford shire blue bricks (the temporary portions of the caisson being removed). At this height a connection was made with the existing pier as follows: The old cutwater was taken down and a granite skew- back set in the existing pier ; from this a granite connecting arch was sprung resting on a skewback on the new portion of the pier. The span of this arch is 13 ft. with a rise of 2 ft. 6 in., the keystone being 4 ft. 6 in. deep ; above this point the existing and the new work being connected, the latter was carried up to match the existing pier in every respect, except that up to the line of spring ing of the existing cast-iron ribs, the work is faced with Staffordshire blue bricks, and that above this line of springing there was no necessity to reduce the width by arranging a skewback for the ribs. When the piers and abutments were carried up to the required height, a block of granite 2 ft. 6 in. thick and 5 ft. wide was laid to take the bedplates of the main girders.
The fixing in position of the main girders for the widened portion of the bridge was as follows: Each girder for the side spans was riveted up complete on the shore, with one end projecting over the river, which was taken hold of by strong sheer-legs fixed upon a barge lying close to the abutment, the opposite end of the girder being made to slide freely. At high tide the barge was pulled over to the pier, taking the girder with it, and landing it on the bearings on the pier; the girders for the centre span were built on the side span and launched in the same manner. See Fig. 2.
The arched top chords are of open box section (open at the bottom). At some point the top chords of the central girders were stiffened using angle sections bolted to the underside (see Fig. 14).
The bottom chords are box section open at the top (Figs. 14 & 15).
On the bottom flange the girders were connected together by Braithwaite and Kirk’s trough flooring 1/2" thick, 2 ft. corrugations, and 9 in. deep, which formed a decking to which the longitudinal baulks 16" by 7" were bolted, to carry the rails and chairs. The deck arrangements have been extensively altered. Fig. 15 shows longitudinal beams supported by I-section beams (probably universal beams) which extend the full width of the bridge, suspended from the bottom chords of the main girders.
Fig. 16 shows the underside of the passenger walkway, with its cantilvered beams riveted to the main girder bottom chords.
2023 Footbridge
An attractive footbridge - Dukes Meadows Footbridge - was opened in 2023 to allow the Thames Path to run beside the river at this point, passing under the railway bridges.