WORLD'S LONGEST BRIDGE SPAN— PAINE 569 



held 40 coils all spliced together into one continuous wire 160,000 

 feet long. Splices were made by pressing an alloy steel sleeve onto 

 the two ends which were to be joined, the ends having first been placed 

 in an hydraulic press which made them oval in cross section and left 

 deep corrugations in their surfaces. These splices were so good that 

 in most tests the wire broke outside the splice. 



Before cable wire could be erected it was necessary to build "cat- 

 walks" upon which the workmen could stand. These catwalks were 

 16 feet wide and reached from anchorage to anchorage passing up over 

 the intervening towers and following the curve which the cables would 

 take, but located so that they would lie about 3 feet below them at all 

 points. The catwalks were simply board walks carried by 12 wire 

 ropes 1%6 inches in diameter and spaced 18 inches apart. These wire 

 ropes between towers were erected by fastening one end at the base of 

 one tower and then laying the rope along the bottom of the Gate to 

 the other tower. It was then hoisted into position and fastened at the 

 tower tops. Adjustment was provided in the attachment of the ropes 

 so they could be lengthened or shortened as required to suit the sag of 

 the cables which, of course, varied as the weight of the suspended 

 structure was applied. The wood floor of the catwalks was painted 

 with fire-resistant paint so as to minimize the danger of fire. At 

 intervals of 100 feet a 12-foot section was applied to a steel frame so 

 that it could be quickly removed to form a fire stop. 



Essentially the "spinning" of the cables consists of taking bights 

 of cable wire from the reels at one anchorage and p idling them across 

 to the opposite anchorage where they are looped over a shoe which in 

 turn is fastened to the anchorage. Each shoe (called "strand-shoe") 

 is capable of holding all the wires that go to make up one strand. 



The 61 strands that make a cable average 452 wires each. The 

 spinning wheel assemblies which shuttled back and forth consisted of 

 four sheaves, three of which always carried a bight of wire; thus six 

 wires were laid at each passage. The spinning wheels were attached 

 to endless haiding ropes by means of which they were pulled along their 

 course at the rate of over 600 feet per minute. Four such spinning 

 units were always in operation simultaneously spinning on four strands 

 at one time. Many days saw 1,000 miles of wire placed in 8 hours of 

 working time. The four strands during spinning were supported in 

 temporary position above and a Uttle to one side of the cable. As each 

 set of four strands was completed, they were lifted one by one from 

 their spinning positions and placed in their final positions in the cable, 

 pinned in place at the anchorages, and then adjusted accurately to 

 length by taking up or letting out at the strand shoe where special 

 means for adjustment was provided. 



When all strands were completed the cables were compacted by 

 means of a machine which encircled the cable and by hydraulic pressure 



31508—38 40 



