tailieunhanh - Steel Bridge Construction-4

Steel Bridge Construction Figure Manufacturing facility for production of shop-fabricated parallel-wire strands (PWS). Prior to 1966, parallel-wire suspension bridge cables had to be constructed wire-by-wire in the field using the aerial spinning procedure developed by John Roebling in the mid-19th century (refer to Figures and ). In the early 1960s a major . steelwork contractor originated and developed a procedure for manufacturing and reeling parallelwire strands, as shown in these patent drawings. A PWS can contain up to 127 wires (see Figures and ). (a) Plan view of PWS facility. Turntables 11 contain “left-hand” coils of wire and. | Durkee J. Steel Bridge Construction Bridge Engineering Handbook. Ed. Wai-Fah Chen and Lian Duan Boca Raton CRC Press 2000 Figure Manufacturing facility for production of shop-fabricated parallel-wire strands PWS . Prior to 1966 parallel-wire suspension bridge cables had to be constructed wire-by-wire in the field using the aerial spinning procedure developed by John Roebling in the mid-19th century refer to Figures and . In the early 1960s a major . steelwork contractor originated and developed a procedure for manufacturing and reeling parallelwire strands as shown in these patent drawings. A PWS can contain up to 127 wires see Figures and . a Plan view of PWS facility. Turntables 11 contain left-hand coils of wire and turntables 13 contain right-hand coils such that wire cast is balanced in the formed strand. Fairleads 23 and 25 guide the wires into half-layplates 27 and 29 followed by full layplates 31 and 32 whose guide holes delineate the hexagonal shape of final strand 41. b Elevation view of PWS facility. Hexagonal die 33 contains six spring-actuated rollers that form the wires into regular-hexagon shape and similar roller dies 47 49 50 and 51 maintain the wires in this shape as PWS 41 is pulled along by hexagonal dynamic clamp 53. The PWS is bound manually with plastic tape at about 3 ft 1 m intervals as it passes along between roller dies. The PWS passes across roller table 163 then across traverse carriage 168 which is operated by traverse mechanism 161 to direct the PWS properly onto reel 159. Finally the reeled PWS is moved off-line for socketing. Note that wire measuring wheels 201 can be installed and used for control of strand length. 2000 by CRC Press LLC Figure Suspended deck steelwork erection the Newport Bridge suspension spans Narragansett Bay . 1968. The closing mainspan deck section is being raised into position by two cable travelers each made up of a pair of 36 in m wide-flange rolled beams that