The Viaduct Works' Handbook

8 BARRAKUR BRIDGE.—This bridge consists of ten spans, of 155 feet each ; total length, 1650 feet, situated over the Barrakur River, in India; made on Kennard and Warren’s patent principle. Its chief novelty consists in being so constructed as to be entirely put up with bolts, thereby obviating the labour of rivetting, which, in a tropical climate, where skilled labour is scarce, is almost a neces- sary consideration. The joints of the compression bars are formed without side flanges of angle iron, which are planed and accurately fitted, so as to be put together with great facility. It is con- structed to carry an 18-feet width of macadamized road over the top, there being three main girders in each opening; the centre one is stronger than the outer ones. The floor is of wood, which was provided abroad; cast-iron parapet, like that for Crumlin Viaduct, is used, and the piers or supports are of stone; the iron used is about 89 tons in each span or opening; and, taking the price as before, gives the cost €1,424 per span, or about €9 5s. per foot run. Murray River Bridge, designed by W. Dempsey, Esq., C.E., of 26, Great George Street, Westminster, London, for Australia, another example of the same class of bridges recently made at Crumlin, is arranged for carrying the floor for road at the bottom. It is for a macadamized road 22 feet wide, and a footway supported outside the girders 3 feet wide on each side, with overhead arched stays. It has five spans of 121 feet centre to centre of supports, and is supported upon iron piers of the cylindrical form 8 feet diameter, more particularly described under that heading. This, like the last example, is arranged so that all the parts which have to be put together abroad are bolted, and no rivetting is necessary, and can therefore be erected by unskilled workmen. The top flanges or compression bars of main girders are of the semi-rectangular tube section, with thickening plates 24 inches wide, varying in number ac- cording to the strain, and are put together at the joints with turned bolts in drilled holes. The bottom flanges or tension bars consist of flat bars, and are jointed by steel pins turned oval and fitted in corresponding bored holes. Diagonal struts are of the II form of section, and ties of flat bars. The roadway is suspended by suitable connexions from the main girders upon light transverse girders of the open lattice description, at about 9 feet apart, pro-