Civil Engineering heritage: Scotland - Lowlands and Borders

The original Rutherglen Bridge was a five-span segmental arch stone bridge, 16 ft wide between parapet faces, built in 1774–75 to the design of James Watt and costing about £2000. It had segmental arch spans from 60 ft–65 ft–70 ft, all with the same radius of 41 ft, and 1 in 25 gradients from the abutments to the centre. Watt drew the plan on 19 April 1774, during the same week that he was preparing plans for his Caledonian Canal proposal with 32 locks. The specification called for the piers to be founded on fir platforms 3 ft below the lowest part of the river bed surrounded by 4 in. grooved sheeting piles driven down 6 ft. Each pier was to be founded on 56, 9 in. diameter iron-shod bearing piles 8 ft long. Execution was to be within cofferdams until the masonry was brought above water, and the spaces between pile heads were to be filled with rammed rubble. Watt’s drawing shows weight reduction provision by means of spandrel cavitation above a central arch pier and in the longitudinal form practised by Smeaton at Perth Bridge (6-16). The outside spandrel walls were ‘to be 4 ft thick and the remaining space is to be divided into three by two walls of 20 in. running the lengthway of the bridge. These spaces are to be covered at the top by three Gothic (pointed) arches of two feet rise.’ Watt’s bridge, despite its narrowness and steep roadway, lasted well but the removal of the weir on completion of a temporary service bridge hastened its demise in 1890. The temporary bridge, of eight timber spans of 32 ft and a central steel span of 55 ft, was erected by Hugh Kennedy & Sons, Partick, at a cost of £2936.

R Paxton and J Shipway 2007

Reproduced from 'Civil Engineering heritage: Scotland - Lowlands and Borders' with kind permission of Thomas Telford Publishers.