381 BRIDGETON — BRIGHT centre girder, the weight of the cantilever itself, the rolling load towers on the piers supported chains attached to the arched ribs on half the bridge, and the wind pressure. The anchors are built at suitable points. In spite of careful provision, much difficulty up of steel plates and angle bars, and are buried in a large mass of was experienced in making the connexion at the crown, from the concrete. The area of each anchor plate, normal to the line of expansion due to temperature changes. The Douro Bridge was stress, is 32 ft. by 12 ft. The bridge was designed by Sir A. similarly erected. The girders of the side spans were rolled out Eendel, the consulting engineer to the Indian Government. so as to overhang the great span by 105 ft., and formed a platform In the United States, few railway companies design or build their from which parts of the arch could be suspended. Dwarf towers, own bridges. General specifications as to span, loading, &c., are built on the arch ring at the fifth panel from either side, helped furnished to bridge-building companies, which make the design to support the girder above, in erecting the centre part of the arch under the direction of engineers who are experts in this kind of (Seyrig, Proc. Inst. G. E. Ixiii. p. 177). The great cantilever work. The design, with strain sheets and detail drawings, is sub- bridges have been erected in the same way, and they are specially mitted to the railway engineer with estimates. The result is that adapted for erection by building out. (w. C. U.) American bridges are generally of well-settled types and their members of uniform design, carefully considered with reference to Bridgeton, capital of Cumberland, county, New convenient and accurate manufacture. Standard patterns of Jersey, U.S.A., situated in 39° 26' N. lat. and 74° 14' details are largely adopted, and more system is introduced in the workshop than is possible where designs are more varied. Riveted W. long., in the southern part of the state, on Cohansey plate girders are used up to 50 ft. span, riveted braced girders Creek, which is tidal and navigable at this point. It is for spans of 50 ft. to 75 ft., and pin-connected girders for longer entered by two railways, the Central of New Jersey and spans. Since the erection of the Forth Bridge, cantilever bridges the West Jersey and Southern. Population (1880), have been extensively used, and some remarkable steel arch and 8722; (1890), 11,424; (1900), 13,913. suspension bridges have also been constructed. Overhead railways are virtually continuous bridge constructions, and much attention Bridgwater, a municipal borough (extended in has been given to a study of the special conditions appertaining to 1896), seaport, and market town in the Bridgwater parliathat case. mentary division of Somersetshire, England, 12 miles N.E. Consideration of the local conditions affecting the of Taunton by rail, on the Parret. Recent erections are erection of bridges is always important, and sometimes a corn exchange and waterworks; the infirmary has been Erection ^ecomes a controlling factor in the determina- enlarged. The value of foreign and colonial imports in tion of the design. The methods of erection 1900 was <£104,827 ; of exports of produce and manufacmay be classed as—(1) erection on staging or falsework; tures of the United Kingdom, £5682. The tonnage (2) floating to the site and raising; (3) rolling out from entered in 1900 was 162,626 (of which 148,870 tons was one abutment; (4) building out member by member, the coasting); the tonnage cleared was 159,889 (of which completed part forming the stage from which additions 157,640 tons was coasting). The registered shipping in are handled. 1901 was 90 sailing vessels of 5724 tons, and 10 steamers (1) In erection on staging, the materials available determine the of 499 tons. Population on the enlarged area (1891), character of the staging ; stacks of timber, earth banks, or built- 13,264; (1901), 15,209. up staging of piles and trestles have all been employed, also iron staging, which can be rapidly erected and moved from site to site. Bridport, a municipal borough, seaport, and market The most ordinary type of staging consists of timber piles at town in the Western parliamentary division (since 1885) nearly equal distances of 20 ft. to 30 ft., carrying a timber plat- of Dorsetshire, England, 18 miles W. of Dorchester, on form, on which the bridge is erected. Sometimes a wide space is left for navigation, and the platform at this part is carried by a the Brit, and a branch of the Great Western railway. timber and iron truss. When the headway is great or the river Area, 571 acres. Population (1881), 6795; (1891), 6611 ; deep, timber-braced piers or clusters of piles at distances of 50 ft. (1901), 5710. to 100 ft. may be used. These carry temporary trusses of timber or steel. The Kuilenburg Bridge in Holland, which has a span of Brieg, a town of Prussia, province of Silesia, on the 492 ft., was erected on a timber staging of this kind, containing Oder, 26 miles S.E. from Breslau, by the railway to 81,000 cubic feet of timber and 5 tons of bolts. The bridge Beuthen. It is an industrial place, manufacturing cigars, superstructure weighed 2150 tons, so that 38 cubic feet of timber millstones, ribbons, leather, machinery, paper, and sugar. were used per ton of superstructure. (2) The Britannia and Conway Bridges were built on staging on The castle (begun 1544) is now used as a military store. shore, lifted by pontoons, floated out to their position between the Population (1885), 18,899; (1895), 21,164. piers, and lastly lifted into place by hydraulic presses. The BrighOUSG, a municipal borough (1893) in the Moerdyk Bridge in Holland, with 14 spans of 328 ft., was erected in a similar way. The convenience of erecting girders on shore is Elland parliamentary division of the West Riding of very great, but there is some risk in the floating operations and a Yorkshire, England, 4 miles N.E. of Huddersfield by rail, good deal of hauling plant is required. (3) If a bridge consists of girders continuous over two or more ; on the river Calder. It is governed by a mayor, 8 aiderspans, it may be put together on the embankment at one end and men, and 24 councillors. There are a technical school, a rolled over the piers. In some cases hauling tackle is used, in others theatre and opera-house, and a public library, opened in power is applied by levers and ratchets to the rollers on which the 1898 in commemoration of Queen Victoria’s Diamond girders travel. In such rolling operations the girder is subjected Jubilee. The corporation owns gas, water, and electricto straining actions different from those which it is intended to resist, and parts intended for tension may be in compression ; lighting works, but a new scheme of electric lighting has hence it may need to be stiffened by timber during rolling. The been adopted. Extensive sewage works were commenced bending action on the bottom boom in passing over the rollers is in 1896. Population of municipal borough area (1891), also severe. Modifications of the system have been adopted for 20,666; (1901), 21,735. bridges with discontinuous spans. In narrow ravines a bridge of one span may be rolled out, if the projecting end is supported on Bright, Sir Charles Tilston (1832-1888), a temporary suspension cable anchored on each side. The free end telegraph engineer, the youngest son of Mr Brailsford is slung to a block running on the cable. If the bridge is erected when the river is nearly dry a travelling stage may be constructed Bright, was born on 8th June 1832, at Wanstead. He was to carry the projecting end of the girder while it is hauled across, employed from very early youth in telegraph work. At the the other end resting on one abutment. Sometimes a girder is age of twenty he became engineer to the Magnetic Telegraph rolled out about one-third of its length, and then supported on a Company, and in that capacity—the telegraphs had not floating pontoon. (4) Some types of bridge can be built out from the abutments, at that time been taken over by the State—superintended the completed part forming an erecting stage on which lifting the laying of lines in various parts of Great Britain. appliances are fixed. Generally, in addition, wire cables are He was also working out in conjunction with his brother stretched across the span, from which lifting tackle is suspended. many valuable telegraphic inventions. In 1853 he laid the In bridges so erected the straining action during erection must be studied, and material must be added to resist erecting stresses. first submarine cable between England and Ireland. His In the case of the St Louis Bridge, half arches were built out on experiments soon convinced him of the practicability of either side of each pier, so that the load balanced. Skeleton signalling electrically between the British Isles and
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