AASHTO M277-06 pdf free download
AASHTO M277-06 pdf free download.Wire Rope and Sockets for Movable Bridges.
3.12. pitch (lay length)- the distance parallel to the longitudinal axis in which a wire makes a complete turn about the axis of the rope. . 3.13. preformed strand- a strand in which the wires are permanently shaped to the spiral form they assume in the strand. 3.14. preformed wire rope- a wire rope in which the strands are permanently shaped to the spiral form they assume in the wire rope. 3.15. prestretching- stretching is the result of two components: the structural stretch, caused by the lengthening of the rope lay, compression of the core, and adjustment of the wires and strands to the load; and the elastic stretch caused by elongation of the wires. Prestretching is the application of a prescribed tensile force prior to delivery (see Section 5.2.4) intended to permanently adjust the rope for most of the structural stretch component, so that when it is placed in service the elastic stretch will be the only significant cause of additional elongation. 3.16. regular lay- designates that the wires in the rope strand lay in one direction while the strand itself rotates in the rope in an opposite direction. The rope has, therefore, an outward appearance that all wires in the rope are roughly parallel to the longitudinal axis of the rope. There are two regular lays, as follows: 3.16.1. right regular lay (commonly called“regular lay “)- -the strands run in the rope downwards to the right (clockwise) while the wires in the strands rotate to the left (counterclockwise). This is the : most used lay.3.16.2. left regular lay- -the strands in the rope run downwards to the left (counterclockwise) while the wires in the strand run to the right (clockwise). (See Figure 1.) The left regular lay is not a commonly used lay and must be specifically ordered. 3.17. reels, manufacturing- reels on which the strands and the wire ropes are wound in one continuous length as they are formed on the rope closing machine. 3.18. reels, shipping- reels on which wire strands or wire ropes, cut to the ordered lengths, are wound from the manufacturing reel for shipment. 3.19. rope- -a symmetrically arranged and helically twisted assembly of strands. 3.20. sockets- type of wire ftting, including bridge sockets, which are steel castings with baskets for securing rope ends and equipped with adjustable bolts. Closed type as“U-bolt” with or without a bearing block in the U of the bolt. Open type has two eyebolts and pin. 3.21. strand- a symmetrically arranged and helically twisted assembly of wires. 3.22. 6 x 19 wire rope- a common type of construction composed of six strands, each strand containing an equal number of wires, ranging between 15 and 26. The six strands are helically twisted around a core of polypropylene, natural hard fiber, an independent wire rope, or a strand.5.1. Base Metal- Wire rope and strand shall be made of improved plow steel. The steel for wires shall be made by the basic oxygen or electric furnace processes. 5.2. Construction of Wire Rope: 5.2.1. The actual diameter of wire rope (the diameter of a circumscribed circle) shall be measured when the rope is unstressed. The measurement shall be made as required in Section 10.1.2. The tolerance from nominal diameter of bright wire rope shall be – 0 percent to +5 percent. 5.2.2. All ropes shall be preformed wire rope of6 x 19 filler wire construction with a hard fiber or polypropylene core. 5.2.3. Ropes shall be laid in accordance with the best practice. Every effort shall be made to obtain ropes of uniform physical properties. The ropes shall be fabricated in the greatest lengths practicable, and all similar ropes for any one bridge shall be cut from ropes manufactured with one setting on one closing machine.AASHTO M277-06 pdf download.
