White Cart Bridge, Inchinnan
White Cart Bridge is a Scherzer rolling lift bascule bridge between Inchinnan and Renfrew, taking the A8 Inchinnan Road across White Cart Water at the confluence with the Black Cart River. The bridge is still capable of opening.
Constructed in 1923 by William Arrol and Co to replace a swing bridge.
The bridge was described, with numerous illustrations, in The Engineer, 30 March 1923. These illustrations include the old swing bridge, which was of the twin leaf cast iron arch type, and the temporary retractable bridge, which was powered by a petrol engine-driven winch.
At the machinery/pivot end, steel cylinders were sunk under air pressure to a depth of about 45 ft. where a firm foundation on boulder clay was reached, and the cylinders were filled with concrete. There are four cylinders, supporting the track girders over which the quadrant rolls.
90 ft clearance between fenders. The quadrant girders have a radius of 20 ft.
The main motors, supplied by the Metropolitan-Vickers Electric Co were each designed to develop 50 BHP at 25 Hz, 50 HP. Each main motor was designed to operate the bridge under normal conditions of wind loading assumed at 5 lb. per square foot, and under these conditions the time to open or closo the bridge by one motor was three minutes after the locking of the gates across the roadwvay. The two motors coupled together were capable of operating and controlling the bridge under a wind load of 20 lb. per square foot. An automatic electric brak of the solenoid type was provided on each motor shaft, and so arranged that it was released immediately current was applied to the motors, and gripped immediately current was cut off or when for any reason the supply failed. Each brake was designed to be capable of stopping or holding the bridge in any position. A further emergency brake, controlled by a hand wheel and screw gear, provides a means of holding the bridge in any position under a wind load of 40 lb. per square foot. In the event of any electrical failure, the bridge could be opened and closed by two men in eighty minutes or by four men working simultaneously on both sets of gears in forty minutes. Th ese hand gears are equipped with a fo ot
See Also
Sources of Information
- [1] Wikipedia
- The Engineer 1923/03/30