CN111788365A

CN111788365A - Enhanced cable with increased degree of bonding

Info

Publication number: CN111788365A
Application number: CN201880090505.8A
Authority: CN
Inventors: 列弗·马尔科维奇·扎列茨基; 韦尼阿明·亚历山德罗维奇·哈利托诺夫
Original assignee: Jsc Almastier Genologiz\
Current assignee: Jsc Almastier Genologiz\
Priority date: 2018-03-01
Filing date: 2018-03-01
Publication date: 2020-10-16
Also published as: PH12020552303A1; WO2019168424A1; CA3092447A1; MX2020009029A; JP2021517936A; RU2020130267A; EP3760805A1; US20210372046A1; BR112020017888A2; KR20200127194A; ZA202005572B; AU2018410808A1; EP3760805A4; RU2020130267A3

Abstract

The invention can be used for the production of prestressed reinforcements. The problem of interest is to develop a reinforced cable with an increased degree of bonding, which has a guaranteed structural stability and increases the degree of bonding with concrete, durability and resistance to stress relaxation. In a reinforced cable, a centre line (1) is arranged along the axis of the cable and is provided with helical grooves (2) having a pitch equal to the pitch of the cabling. The strands of the inner layer are disposed within the slots, each of said wires being in contact with the centre line and two adjacent wires of the inner layer. The strands are helically arranged in the outer layer at equal intervals to each other, each of said wires being arranged in a groove between and in contact with the strands of the inner layer.

Description

Enhanced cable with increased degree of bonding

Technical Field

The invention relates to cable production and can be used for the production of pre-stressed reinforcements designed for pre-stressing by abutment and pre-stressing by injection of a channel.

Background

A seven-wire reinforced cable according to GOST R53772-.

A disadvantage of this design is that the degree of bonding with the concrete is relatively low. Although the known cables have an additional mechanical bond in form in the coiling direction, they do not generally provide a high degree of bonding with the concrete due to the low height of the elements of the periodic profile, which elements are not able to maintain the mechanical bond during poisson narrowing when the cable is tensioned under the load applied to the reinforced concrete. In addition, the described elements of periodic profile transmit the stresses of the reinforcement to the concrete fragments directly in the recesses by carrying/shearing loads, thereby transmitting the loads to the blocks by tangential stresses. Moreover, the low degree of bonding is due to the narrow spacing between the circle circumscribing the cable cross-section and the surface of the outer wire, which does not allow room under the cable generatrix to form a strong concrete ridge. Another disadvantage of the known reinforcing cables is the reduced durability and resistance to slackening compared to similar cables made of plain wires. This is due to the fact that the periodic profile forms a large number of stress concentrators, reducing their own mechanical properties, in addition to the fact that the periodic profile on the contact surface causes point contact between adjacent wires, further increasing the stress concentration, and to the fact that the cables increase in length during use in the structure, reducing the pre-tension, and also reducing the resistance to relaxation, due to the fact that the adjacent wires are locally introduced into each other at the contact points and due to the displacement of the smaller laying radius and the direct increase in length of the wires.

The closest prior art of the cable according to the invention is a reinforced cable according to patent RU 2431024, comprising a centreline and a litz wire having a periodic profile wound helically around the centreline. The periodic profile is provided in the form of inclined protrusions above the generatrices of the cable reduction surface and the area of the surface of the wire in contact with the other wire is provided in the form of a flat plane arranged helically. A periodic profile is applied over the outer region of the surface of the litz wire, the spacing between the circle circumscribed about the cable cross-section and the surface of the outer wire having an increased size compared to the spacing in a round wire cable, due to the shape of the wire cross-section and the arrangement of the wires with the region extending onto the cable outer surface in two layers, such that the profile of the outer region tangentially connecting the litz wire approximates a triangle with rounded corners.

The known cable has a high degree of bonding due to the inclined surface formed by the helically twisted triangular section, which allows the stresses of the reinforcement to be transmitted to the concrete by means of a supporting reaction (i.e. normal stresses, the allowed value of which is higher than the allowed value of tangential stresses), and also allows the contact between the concrete and the surface of the reinforcement not to be lost during its poisson narrowing. In this case, the greater spacing between the circle circumscribing the cable cross-section and the surface of the outer wire (which leaves room for a strong concrete ridge to form under the cable generatrix) and the increased envelope profile are other factors that increase the degree of bonding.

Furthermore, the known cable has an increased durability compared to the prior art discussed previously, due to the surface contact between the wires, the lower number of elements of the periodic profile and their arrangement only in the area of the wires extending above the outer surface of the cable and the plastic compression surface, which reduces the stress concentration when applied.

A disadvantage of the known cable design is the insufficient stability of the high degree of bonding, which is limited by the structural instability of the cable due to the possibility of pressing one strand of the outer layer into a smaller radius between the strands of the inner layer and displacing them sideways during the passage of the cable along the pulleys and guides during production, as a result of which the predetermined mutual position of the wires is lost and the outer surface of the cable loses the inclined surface providing the bonding by interlocking. This change in cable configuration results in a multiple reduction in its bond to the concrete. Also, local variations in the cable configuration lead to increased loads on the wires where their mutual position varies, which may have a negative effect on the durability and resistance to slackening of the cables.

Disclosure of Invention

It is an object of the present invention to develop a reinforced cable with an increased degree of bonding, which has a guaranteed structural stability and thus sufficiently provides an increased degree of bonding with concrete, durability and resistance to relaxation.

The problem is solved by the fact that in a reinforced cable with increased degree of bonding, comprising a centre line and strands arranged helically in two concentric layers around the centre line, wherein on the centre line a helical groove is provided in the direction of cabling, the pitch of the helical groove being equal to the pitch of the cabling, and the strands of the inner layer are arranged in these grooves, and each strand is in contact with the centre line and two adjacent strands of the inner layer, and three strands are helically arranged in the outer layer at equal intervals to each other, each said line being in contact with two adjacent strands of the inner layer, between which two adjacent strands of the inner layer each said line is arranged in a groove. In this case, it is most reasonable to design a cable having six strands of the inner layer and three strands of the outer layer, each of the six strands of the inner layer being disposed in a groove on the surface of the center line.

The centre line provided with a helical groove ensures a rigid fixation of the position of all strands of the inner layer relative to the centre line and avoids that the strands of the outer layer are squeezed between the wires of the inner layer with a lateral displacement thereof. This ensures the stability of the required cable configuration.

In this case, the spiral grooves on the center line may be arranged at equal intervals from each other and at larger intervals and smaller intervals alternating with each other.

The strands of the outer layer can be provided with a smaller cross section than the strands of the inner layer.

The helical surface continuous in the length direction may be provided in a facing region of the surface of the adjacent strand and in a region of the surface of the strand of the inner layer facing outwardly. The helical surface can also be arranged in an outwardly facing region of the surface of the strand of the outer layer.

A periodic profile may be provided on the surface of the one or more strands. For example, the periodic contour may be in the form of oblique projections over the surface of the helicoid in the outwardly facing region of the surface of the strand.

In this case, the wires of the cable may have an anti-corrosion coating, for example based on zinc.

Drawings

The invention is explained by means of the figures.

Fig. 1 schematically shows the appearance of a reinforcing cable with an increased degree of bonding of a 1+6+3 structure;

fig. 2 schematically shows a cross section of the reinforcement cable of fig. 1.

Detailed Description

In fig. 1 to 2 a reinforcement cable according to one of the embodiments of the present invention is shown. A straight centre line 1 is arranged along the axis of the cable and is provided with six helical grooves 2 on the surface, in which six litz wires 3 of the inner layer are arranged, which lines are closely adjacent to each other and lie on the grooves 2 of the centre line 1. In the spaces between the strands 3 of the inner layer, there are three strands 4 of the outer layer, which are in close proximity to the strands 3 of the inner layer. The area of the surface of the inner layer strand 3 in contact with the surface of the adjacent strand 3 of the inner layer and the outer layer strand 4, and the area of the surface of the outer layer strand 4 in contact with the surface of the inner layer strand 3, are provided in the form of a helicoid 5, which represents a linear area of the surface of the wire and has a macroscopic border with the remaining surface of the wire. In the region of the inner strand 3 and the outer strand 4, which extend to the outer surface of the cable, there are respectively a

helical surface

6 and 7, wherein each strand 3 of the inner layer has one helical surface 6 and each strand 4 of the outer layer has two helical surfaces 7. On the surface of the inner layer strand 3, a periodic contour in the form of a projection 8 is applied to a generatrix of the helicoidal surface 6.

The design of the reinforcing cable as described above results in a maximum structural stability of the cable.

The reinforced cable is manufactured as follows.

A wire 1 having a helical groove 2 applied to the surface and

wires

3 and 4 of circular cross-section are previously manufactured. During manufacture, the wire may be coated with, for example, a zinc-based corrosion protection coating. The wires are then laid together to form the cable using any known cable twisting machine, for example of the trailing type. Laying directly in the centre of the wire causes the wire to be reduced in a gauge roller (gauge roller) having an inclined roller rotating with the rotor of the wire twisting machine. As a result of the reduction, the wires are pressed and deformed tightly against each other, while the helicoids 5 are formed on the contact surfaces of the inner and

outer strands

3 and 4, respectively, and the

helicoids

6 and 7 are formed on the surfaces of the cable at the interaction points between the

strands

3 and 4 and the gauge rollers, respectively. At the same time as the cable is reduced, a periodic contour in the form of a protrusion 8 above the generatrix of the helicoidal surface 6 is applied to the inner strand 3.

The formed cable is then tensioned to 30% to 80% of the breaking force by any known method, for example, between two capstans, each capstan being a device consisting of a drive pulley and a non-drive pulley or two drive pulleys. In the interval between the first capstan and the second capstan, when the reinforcing cable is in a straight-line tensioned state, it is heated to 370-.

After cooling is complete, the cable passes through the second capstan and to the storage coil. After the cable twisting machine has consumed the wire on at least one of the coils mounted in its rotor or the outer coil has been unwound, the process is interrupted to fill the cable twisting machine with the wire while replacing the storage coil with a similar empty storage coil, the filled storage coil is displaced to a rewinding area where the finished cable wound on the storage coil is rewound onto a container coil or spool and packaged by known methods.

Claims

1. A reinforced cable with increased bondability, comprising a centre line and strands helically arranged in two concentric layers around the centre line, wherein a helical groove is provided on the centre line in the direction of cabling, the pitch of the helical groove being equal to the pitch of cabling, and the strands of the inner layer are provided in these grooves, and each strand is in contact with the centre line and two adjacent strands of the inner layer, and the strands are helically arranged in the outer layer at equal intervals to each other, each said line being in contact with two adjacent strands of the inner layer, between which two adjacent strands of the inner layer each said line is provided in a groove.

2. The reinforcement cable of claim 1, wherein the reinforcement cable has an inner six strands and an outer three strands, each of the inner six strands being disposed in a groove on a surface of the centerline.

3. The reinforced cable of claim 1, wherein the helical grooves on the centerline are equally spaced from one another.

4. The reinforced cable of claim 1, wherein the helical grooves on the centerline are disposed at alternating larger and smaller intervals from one another.

5. The reinforcement cable according to any one of claims 1 to 4, wherein the strands of the outer layer have a smaller cross-section than the strands of the inner layer.

6. The reinforcement cable according to any one of claims 1 to 5, wherein a helicoid that is continuous along the length is provided in facing areas of the surfaces of adjacent strands, and the helicoid is further provided in an outwardly facing area of the surface of the inner layer strand.

7. The reinforcement cable of claim 6, wherein the helical face is further disposed in an outwardly facing region of a surface of the outer layer of strands.

8. The reinforcement cable of any one of claims 1 to 7, wherein the at least one strand has a periodic profile on a surface thereof.

9. The reinforcement cable of claim 8, wherein the periodic profile is in the form of an oblique protrusion over the surface of the helicoid in an outwardly facing region of the surface of the strand.

10. The reinforced cable of any one of claims 1 to 9, wherein the wires have an anti-corrosion coating.

11. The reinforced cable of claim 10, wherein the major component of the corrosion protection coating is zinc.