JPS6199532A - Pc-steel composite stranded wire - Google Patents

Abstract

PURPOSE:To obtain a composite stranded wire excellent in breaking load and elongation properties by forming a titled stranded wire so as to make a mutual contact angle between its base wires as small as possible in the composite stranded wire formed by concentrically intertwisting plural strands. CONSTITUTION:A composite stranded wire is formed by making the twisting directions of respective layers alternately opposite, and the twisting direction of said each layer opposite to that of the outer layer of the stranded wire forming each layer. As well as a composite stranded wire is formed by making the twisting direction of the outer layer of a central stranded wire equal to that of the layer of the former composite stranded wire adjoining to the stranded wires of the latter composite stranded wire. For instance, in case of a composite stranded wire formed by intertwisting seven stranded wires consisting each of seven base wires; six child stranded wires are intertwisted in Z direction around a child stranded wire 1 formed by intertwisting seven base wires 3. Then the twisting direction of the outer layer of the child stranded wire 1 is Z twisting, and that of the outer layer of child stranded wire 2 is S twisting. In this way, the contact angle between the base wire 3 of the outer layer of child stranded wire 1 and the base wires 3 of the outer layer of child stranded wire 2, is decreased; and the contact surface at the contact part is increased; then a slant shearing stress is decreased to make the wire 3 hard to break.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a stranded wire (child stranded wire) in which a plurality of strands are twisted together in a PCA stranded wire used for prestressed concrete (hereinafter referred to as PC). This refers to a composite stranded wire (referred to as Oyahiro wire) made by concentrically arranging a plurality of wires (referred to as Oyahiro wire).

(Background technology) Currently, 7-strand method and 19-strand twisted wire are commonly used as PCAM wires, but when an even larger load is required, 7 or 19 of the 7-stranded wires are further twisted to create a super-high-strength PCAM wire. It may be used as a diameter cable.

When performing a tensile test on such a super large diameter cable, as shown in Figure 3, the center (or inner layer) of the jllffl wire 1)
The strands 3 of the child twisted wires 12 of the outer layer and the child twisted wires I2 of the outer layer are pressed together at their contact point IO. In this case, at the contact point, as shown in Figure 4 (a) (top view) and (b) (side view), the strands 3 and 3 intersect at a contact angle β, and a tensile force T is applied to the strand 3. Therefore, force C acts on the pressing force at the contact point IO, resulting in an oblique shearing force. Due to this oblique shearing force, the strands 3 are broken under low load and small elongation, and the breaking load of the entire parent strand is reduced.

The decrease in the breaking load with ,
Basic! l1) 3 becomes easier to break.

(Disclosure of the Invention) The present invention has been made to solve the above-mentioned problems, and is configured so that the strands of the composite stranded wire are as close to linear contact as possible, so that the contact angle is small. By doing so, we aim to reduce the shear stress acting on the contact point so that the strands can be cut <<L, and to provide a PCam stranded wire structure with excellent breaking load and elongation performance as a composite stranded wire. be.

The present invention provides a PC (1) composite cable consisting of a plurality of twisted wires concentrically twisted, in which the twisting direction of each layer of the composite twisted wire is alternately opposite, and the twisting direction of each layer constitutes each layer. An SPCM composite twisted wire characterized in that the twisting direction of the outer layer of the twisted wire is opposite, and the twisting direction of the outer layer of the center twisted wire is the same as the twisting direction of the layer of the composite twisted wire that is in contact with the twisted wire. It is a line.

Hereinafter, the present invention will be explained by examples using drawings.
do.

FIGS. 1(A) and 1(B) are a cross-sectional view and a screen view showing an embodiment of the present invention, respectively, and show the case of a composite stranded wire in which seven strands of 7-wooden strands are twisted together. In the figure, 1) 2 is a J'l gland made up of 7 wooden strands 3 twisted together, and around the central strand 1, there are 6 children 1fil! 2 are twisted in the Z IW direction. The twist direction of the outer layer of the central child strand 1 is Z twist, and the twist direction of the outer layer H of the surrounding children 1t and fftlj2 is SPa. The dotted lines indicate the strands 3 facing inside of the child strands 2.

If α1 is the twisting angle of the strands of the child strands 1 and 2, and α2 is the twisting angle of the outer circle (6 pieces) of the parent strand, then the strands 3 on the outer surface of the central child strand l and the surrounding children [ The 1st antennae β1 of the strand 3 of the 12 outer circles is β1=-α+-(-α1-α2)=α2...
...... (1) For example, if the twist pitch of the outer layer of child strands 1 and 2 is about 16 times the outer diameter, α, = a, S degrees, and the bitch to be twisted is outside when the parent strands are removed. If it is approximately 16 times the diameter, α2
= 7.5 degrees, and the contact angle β1 in this case is (1)
From the formula, β1 = α2 = 7.5 degrees On the other hand, if the direction of the outer layer of the central child mat is S twist as in the conventional case, the contact angle β1' is β1' = α + - (-
αl−α2)=2α1+α2・・・・■= 2 X
8.5+7.5=24.5 degrees The contact angle β1' of Cong.Song is significantly larger than the contact angle β1 of the present invention.

In addition, instead of making each twist direction as shown in FIG. 1, in the present invention, the twist direction of the outer circle of the 12 strands is S, and the center child 1@! ! The twist direction of the outer circle of i1) may be S twist, and the twist direction of the outer circle of the surrounding child Pa wire 2 may be Z twist, and exactly the same effect as shown in the figure can be obtained.

Next, FIGS. 2A and 2B are a cross-sectional view and a side view showing other embodiments of the present invention, respectively, and FIG. 5 is a side view showing an example of a conventional composite stranded wire. The case of a composite stranded wire made by twisting 13 wood combust stranded wires is shown. In the figure, 4, 5.
6 is a child twisted wire in which seven strands 3 are combined in F21, and six child twisted wires 5 are twisted around the central child twisted wire 4 to form an inner F! J7 is formed, and 12 child twisted wires 6 are further twisted together on the outside thereof to form an outer circle 8. 9 is six filler wires.

In the conventional example shown in FIG. 5, the twist direction of the inner center 7 of the twisted wire is Sp
The twist direction of the outer circle 8 is Z twist, and the child twisted wires 4 and 5
．． The twist direction of the outer layer of No. 8 is all SIV. Here, the twist angle of the child strand wire 4, 5.6, and α2 are j
! If the twist angle of the inner surface 7 of the 1 m wire and α3 are the same as the twist angle of the outer layer 58, then the contact angle between the outer layer element 1a3 of the central child strand 4 and the outer layer element 3 of the child strand 5 of the inner core 7 is β1'. is, β1'=1α+-(α2-α1)1 =+2α1-α21・・・・・・・・・・・・・・・
・f3) Also, the outer layer element t of the child strand 5 of the inner circle 7! The contact angle β2' between i13 and the outer layer strands 3 of the child stranded wires 6 of the outer layer 8 is β2
'=1(α2+α1)-(-α3-α1)1=12α1
+α2+α31・・・・・・(4) On the other hand, the second
In the illustrated example of the present invention, the twist direction of the inner circle 7 of the parent strand wire is S twist, the twist direction of the outer circle 8 is Z twist, which are alternately opposite directions, and the direction of the outer circle of the child strand wire is , the child strands 4 in the center are S-twisted, the child strands 5 in the inner circle 7 are Z-twisted, and the child strands 6 in the outer circle 8 are S-twisted. Here, as in FIG. 5, each twist angle is α1. α2. If α3 is assumed, the child twist at the center is t! i1
The contact angle β1 between the strands 3 of the outer circle of 4 and the strands 3 of the outer layer of the child strands 5 of the inner center 7 is β, = lα + - (α2 + α + N = l - α21 ・ ■ Also, the outer layer of the child strands tla5 of the inner layer 7 f-stranded wire 6 of strands 3 and outer layer 8
The outer layer of the element! ! ; The contact angle β2 of 13 is β2=1(α2
-α1)-(-αlow α1)1=1α2+α31...
・・・・・・ ・・・・・・(6) For example, child twist! ! 94
, 5.6, if the lying pitch of the outer layer is about 16 times the outer diameter, α1 = 85 degrees, and if the twisting pitch of the outer layer of the inner layer 7 of the parent stranded wire is about 16 times the outer diameter, α2 = 7.5. If the twist pitch of the outer layer 8 is approximately 16 times the outer diameter, α3=9.5
(random (2), ■, (0 formula % formula % near t) Therefore, β・'〉β・・β2′〉β2, that is, the contact angle according to the present invention is both that of the conventional example. It is smaller than the contact angle and is significantly improved.

It should be noted that, instead of setting each of the widening directions in the present invention as shown in FIG. 2, the same effects as those shown in the drawing can be obtained even if they are set in the opposite direction of the drawing.

Furthermore, with the above configuration, in the present invention, FIGS.
As shown in the figure, the parent PA t! Even in the outermost layer of Il,
Also, in the inner circle, the angle with respect to the longitudinal axis direction of the wire 3 exposed on the surface side is small at α3-α1 or α2-α1, and is almost zero, which causes the regular grip of the PCalW wire. It has a good regular running effect and prevents diagonal shear breakage of the strands at the fixing part.

(Example) Composite stranded wires as shown in FIG. 5 (conventional example) and FIG. 2 (invention example) were created.

4. Twisting 7 pieces of 22-wire iφ steel wire to create an outer diameter of 12.7s*φ
These 19 wires were twisted together with 6 filler wires of 4.4@Sφ to form a composite stranded wire with an outer diameter of 63.5 mm.

The breaking load of one stranded wire is 19.500, and the elongation (GL
= GIOsm) is 6%, the breaking load of one filler wire is 3,050 kg, and the elongation (GL = 100ts)
7%, so the total breaking load was 388,800.

The breaking load and elongation by the tensile test of the f'J composite (t! line) are shown in Table 1.

Table 1 From Table 1, it can be seen that the specimen according to the present invention has a higher breaking load and elongation than the conventional example.

In the above explanation, mainly 7 or 19 child strands of 7 strands are used.
Although the case where books are twisted together has been described, the present invention is not limited thereto, and the number of child twisted wires may be other than 7, and the number of child twisted wires may be other than 7 or 19. It is clear that the present invention can be similarly applied to those cases and the same effects can be achieved.

(Effects of the Invention) As described above, the PCff1 stranded wire of the present invention made in (1) has the following effects.

(A) The twisting direction of each month of the 1Fs1 joint wire is alternately opposite, and the direction of twisting of each month is opposite to the direction of the outer layer of the twisted wire constituting each month. , since the direction in which external sound enters the middle and deep stranded wires is the same as the twisting direction of the layer of N-stranded wires that is in contact with the stranded wires, the inner layer of the rlA stranded wire and the outer layer Since the angle at which the wires come into contact with each other (contact angle) becomes smaller, the contact area at the contact point where the wires are pressed becomes larger, and the oblique shear stress is reduced, so the wires can be bent with low load and small elongation. No rupture, therefore PC*l'
It has excellent performance with less deterioration in breaking load and elongation performance as W wire.

(1) By configuring the twist direction as described above, both in the outermost layer of the jM 1M wire and in the inner moon, the angle with respect to the longitudinal axis direction of the strands exposed on the surface side is small, and Since it becomes close to zero, the constant volume effect is good when the PC steel wire is gripped in the regular direction, and diagonal shear breakage of the strands in the regular direction P and B can be prevented.

[Brief explanation of the drawing]

Figures 1 (a) and (b), and Figures 2 (a) and (b) respectively show embodiments of the present invention. Figure 1 shows seven stranded wires,
FIG. 2 shows the case of a composite stranded wire in which 13 stranded wires are twisted together, and each figure (A) is a cross-sectional view, and each figure (I'') is a side view. FIG. 3 is a cross-sectional view showing an example of a conventional composite twisted wire. FIGS. 4(a) and 4(b) are diagrams showing the state of the contact points of the strands shown in FIG. 3, in which FIG. 4(a) is a top view and FIG. 4(b) is a side view. FIG. 5 is a side view showing another example of the conventional compound ruled line.
The case of composite thin wire made by twisting wooden strands is shown. 1.4...Center twist 15A (child twist), 2.6...
Outer twist! il (child twist 19), 3... elemental wire, 5...
・Inner layer twisted wire (child twisted wire), 7... Inner layer, 8... Outer layer, 9... Filler wire, 10... Contact point, ■...
・Compound ruled line (already mIi ri, !2... twisted wire (child twisted wire)
, αl, α2. α3...Twisting angle, β...Contact angle. Figure 1 (Rota"7t-2 figure α) (σ)

Claims (2)

[Claims] (1) In a PC steel composite stranded wire formed by concentrically twisting a plurality of stranded wires, the twist direction of each layer of the composite strand is alternately opposite, and the twist direction of each layer and the twist constituting each layer A PC steel composite twisted wire characterized in that the twisting direction of the outer layer of the wire is opposite, and the twisting direction of the outer layer of the central twisted wire is the same as the twisting direction of the layer of the composite twisted wire that is in contact with the twisted wire. line. (2) The PC steel composite stranded wire according to claim 1, wherein the composite stranded wire is a combination of 7 or 19 strands of 7 strands.