JPH0749696B2 - PC steel stranded wire with side wires with different surface colors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a PC steel stranded wire constituting a cable used in a prestressed concrete structure or a suspended structure.

[Prior Art] When tensioning the PC steel wire arranged in the duct in the structure of the prestressed concrete structure or in the protection tube of the suspension material of the suspended structure, at the same time, the total number of PC steel wires is jacked out. When strained, in a large-capacity cable or the like, due to the large size of the duct or the protection tube, the strain of PC steel wire to be strained occurs, and the tension force varies among the individual PC steel wires.

(1) When the number of cables is relatively small and the deformation of the structure due to prestressing is not so large, each PC steel wire constituting the cable is tensioned to a certain load, and After removing Talmi,
Variations can be minimized by simultaneously tensioning the final tension with a large jack.

(2) When a large capacity cable is used, such as a suspended structure, and when tension is applied to the structure, a twist mark is generated on the structure. Place it at one place, place one mark at the fixing and fixing device, place the other mark inside the tension fixing device, and use that mark as a guide until the mark is at a certain distance from the tension fixing device. Variations can be minimized by tensioning the individual strands of PC steel one by one and then simultaneously tensioning them with a large jack to the final tension.

[Problems to be solved by the invention] When strain occurs in a structure due to cable tension,
As in item (2) above, it is necessary to mark the individual strands of PC steel that make up the cable with a mark indicating a predetermined length at positions A and B, for example.

This mark is made by deciding the position corresponding to the predetermined length with a special device in the manufacturing plant and applying paint etc. to the PC steel wire at that position, but after making the mark, the PC steel wire is When wound into a coil, the relative positions of the strands of the outer layer that compose the PC steel strand are displaced. Figure 2 (a),
(B) shows the mark position before winding and the mark position after winding on the outermost strand 1 of the PC steel wire.

In this case, it is necessary to know where A and B are on the same strand, but this is difficult to identify when the strand is longer than PC steel.

Note that when the tape is wound, it is not misaligned even if it is returned to the state before the winding.

[Structure of the Invention] As described above, although the length is previously set between A and B, it is wound and the PC steel strand is returned to the state before winding again. When this A and B
It is only necessary to know the position of the wire, so if one strand of the outermost layer of PC steel wire can be clearly indicated, a mark is added to the strand to shift the relative position between the strands due to winding. Becomes irrelevant. The outermost strand of this PC steel strand 1
As a method of clearly indicating a book, the surface color of this strand may be different from that of other strands.

As shown in FIGS. 1 (a) and 1 (b), one of the strands of the outermost layer of the PC steel strand uses a strand 2 whose surface color is different from that of other strands. (A) shows the mark position before winding, and (B) shows the mark position after winding. This mark corresponds to either the mark position A or B.

As a method of changing the color of the surface of the wire, there is a method of applying paint to the wire before processing, but this paint is more likely to fall during processing.

In the final process, PC steel strands are subjected to low temperature heat treatment, but at this time, the surface of the strands changes color. This change in color tone depends on the lubricant adhering to the surface of the wire or the auxiliary agent for lubrication.

Therefore, for example, it is possible to cause a change in color tone by drawing only the wires that need to be clearly specified, by drawing with a lubricant different from other wires, or conversely by removing the surface lubricant with a brush or the like. .

[Example] As I touched on before, a lubricant is used when wire drawing of PC steel strands. The lubricant at this time, or the lubricant applied to the steel wire surface before wire drawing When the auxiliary agent of the lubricant is changed or brushing is performed, the color of the surface of the steel wire is changed by the low temperature heat treatment after processing, so an example in which such means is adopted will be described.

(1) For 7 strands of PC steel, the center line and 5 side lines are drawn with a lubricant containing calcium stearate as the main component, and the remaining 1 side line is a lubricant containing sodium stearate as the main component. The wire drawn with a lubricant containing sodium stearate as a main component is slightly bluer than the other side wires. It has a tasteful surface,
He can be clearly identified.

(2) If a zinc phosphate coating is used as a lubricant additive on the surface of the steel wire before wire drawing, the surface of the steel wire will become slightly darker due to the low temperature heat treatment after processing, whereas if borax is used, The color of the steel wire surface becomes whitish. Using this, PC
When 5 of the steel stranded wires are treated with a zinc phosphate coating and the remaining 1 is treated with borax, only 1 of these has a whitish color.

(3) When all side wires are drawn with a lubricant containing calcium stearate as a main component, only one of them is brushed at the end of wire drawing to remove the surface lubricant. By further processing using this, and then heating at a low temperature of about 350 ° C., the brushed one has a much bluish surface compared to the other lateral lines, so that he can be clearly identified.

[Effects of the Invention] If the PC stranded wire of the present invention is used as a tension material for a prestressed structure or a suspended structure, one of the outermost strands of the PC stranded wire can be clearly distinguished from other side wires. Because of tension, one mark that can be distinguished from the side line as a reference line is used as a guideline for the tensioning work, and the mark can be easily visually observed, and the tensioning work can be easily performed.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, in which (a) shows a mark position before winding a PC steel wire and (b) shows a mark position after the winding. FIG. 2 shows a conventional method of marking a PC stranded wire, where (a) shows the mark position before winding the PC stranded wire and (b) shows the mark position after the winding. 1 ... strand, 2 ... strand whose surface color is different from other strands.

Claims (1)

[Claims] 1. One or more of the outermost strands have a surface color different from that of other strands by heat treatment, and a mark is attached to a predetermined position on the outer surface of the foreign dye strand. PC steel stranded wire having side wires with different surface colors, which is characterized by being formed.