"merthyr" - 1 õppematerjal

Bridges presentation

(Figure 10). Designed by George Stephenson for the first railway, the 37 miles (23km) between Stockton and Darlington in north-east England, it consists of four 12.5ft (4m) lenticular truss spans with curved top and bottom chord members of 2.5in (6cm) diameter wrought-iron rods and five vertical iron posts cast integrally with the wrought-iron chord members. In the last 20 years an older bridge has been discovered in South Wales (UK) at Merthyr Tydfil, a major early 19th century iron- producing centre. Pont-y-Cafnau (Bridge of Troughs) is a unique cast-iron combined aqueduct tramroad bridge below the confluence of the Taff and Taff Fechan, built in January-June 1793 by Watkin George, Chief Engineer of the Cyfarthfa Ironworks, to carry an edge railway and water channel. An iron trough-like girder is carried in an A-frame truss of cast iron spanning 47ft (14.2m), held together by mortise-and-tenon and dovetail joints