The Works Of Messrs. Schneider And Co.

THE EL CINCA, BREST, AND ORIVAL BRIDG-ES. 133 29 metres (95 ft.) high, which gives a total of 72 metres (236 ft.). The masonry of the basement is hollow ; it measures 20.000 cubic metres (706.400 cubic feet). The girders are 4 metres (13 ft.) high; the trellis of the bridge and piers is made with close intersections. The total weight of the ironwork is 3000 tons. The iron superstructure was first erected on a platform to the real' of one of the abutments ; it was then pushed along so as to bring one end above the masonry basement of the first pier. The ironwork of this pier was after- wards erected, the overhanging part of the superstructure beinef used to facilitate this. In Order not to strain the superstructure during this work, it was supported by a system of columns and cables in the manner of suspension bridges. When the first pier was erected, iis top part was secured to the masonry abutment by stays, and the super- structure was pushed along until the end arrived above the masonry basement of the second pier ; the ironwork of I The bridge is 6 metres (19 ft. 8 in.) wide between railings. This small width made it necessary to provide carefully designeel cross-bracing. The uprights which transfer the weight of the road to the girders are con- nectée! transversely by close trellis-work. This bridge was erected without any scaffolding ; the work was carried from both sides simultaneously, the junetion being effeeted at the key. The top part of the bridge was first firmly secured in the masonry abutments by the ends, and the two brackets thus formed, served as a track for the hoisting machines. A balancecl footbridge which was shifted as the work progressed, served for carrying the workmen ; it was always suspended from the last portion of the arch when erected, and followed the work as it progressed. It was exceedingly difficult to find workmen having sufficient confidence in their chief, to meet the dangers which the érection seemed to involve ; and the Creusot engineers had to be constantly on the foot-bridge in order to encourage the men by Fig. 368. The Stadlau Bridge over the Danube. this second pier was then erected in the same way as the first. Thus the work was carried on until the opposite abutment was reached. It is certain that this work could not be completed at the present time in a more efficient or economical way ; it is not astonishing, therefore, that the process followed for the érection of the bridge attracted great attention at the time, and has been widely imitated. Bridge over the El Cinca River (Figs. 364 and 365, Plate LXXXIL).—Another application of the same process of érection, the boldness of which appeared still greater in the case of this bridge, confirmed its advantages. Messrs. Schneider and Co. erected in a similar manner the iron arched bridge of 70 metres (229 ft.) spån, which they built in 1866 over the river El Cinca, in Spain. This road-bridge crosses the river at a spot where the banks are very steep ; they are about 35 metres (115 ft.) high. The iron girders are four in number and are arched ; the rise is 7.58 metres (24 ft. 10TV in.), and the radius of the soffit 80.040 metres (2G2 ft. 7 in.). their presence. The érection was completed most satis- factorily. Brest Swing Bridge (Fig. 366 and Fig. 367, Plate LXXXII).—This bridge was built a few years befoi-e the one above described, namely, in 1860, and was a very remarkable work. It unités the Recouvrance suburb to the town of Brest over the Penfeld, leaving a free height of 19.500 metres (64 ft.) above the highest water-mark. The distance between the piers is 105.700 metres (346 ft. 9 in.), and from centre to centre of piers 117,600 metres (385 ft. 10 in.). The structure is turned by toothed-wheel gearing worked by hånd. The girders are 7 metres (23 ft.) high ovei’ the piers. The weight of wrought-iron work forming the bridge is 850 tons ; there are, besides, 320 tons of cast iron, the gearing contributing largely to this figure. Orival Bridge.—This bridge, which was built for two railway tracks in 1864, is formed of six bays of straight continuons girders, 50.800 metres (166 ft. 7 in.) spån. Its érection was one of the remarkable operations of the period. 2d