KR102321188B1 - Friction wedge for prestressing strand and the construction method thereof - Google Patents

Abstract

The present invention relates to a frictional wedge, which is used to fix a PC strand on a settlement hole as the PC strand is highly strengthened and solves a problem in which settling effect is reduced as a hardness of a surface approaches a critical point, and a construction method thereof. The frictional wedge does not have a thread groove in an inner lateral surface and comprises a plastic deformation material, which is formed on the slice inner lateral side, and a surface protruded frictional material, which is integrated with the plastic deformation material. In a plastic deformation process of the plastic deformation material when the PC strand is settled, the surface protruded frictional material secures frictional force by being engaged with the PC strand.

Description

Friction wedge and its construction method

The present invention relates to a friction wedge and its construction method. More specifically, as the PC stranded wire is strengthened, the wedge used to fix the PC stranded wire to the anchorage is a friction-type wedge that can solve the problem that the fixing effect decreases as the hardness limit of the surface comes, and its construction method will be.

Figure 1a shows an exemplary view of fixing by the conventional PC stranded wire (S) and the wedge (30).

The PC stranded wire (also referred to as S or PS stranded wire) is a strand used in cable bridges, etc., and is formed so that a plurality of strands are twisted with each other.

Such a PC stranded wire (S) is such that the outer peripheral surface of the PC stranded wire (S) is bitten on the inner surface of the slice of the wedge 30 that is divided into two or three, and the outer surface of the slice is inserted into the inner peripheral surface of the fixing hole of the anchorage, and after tension, will be settled

Accordingly, it can be seen that the wedge 30 bitten to the outer peripheral surface of the PC stranded wire (S) has a screw groove formed on the inner surface to secure the required frictional force, as shown in FIG. (S) It can be seen that the engagement groove (A) is formed while being bitten by the outer circumferential surface.

That is, it can be seen that the wedge 30 is integrated while digging into the outer peripheral surface of the PC stranded wire (S) and is inserted into the fixing hole of the anchoring tool to fix the PS stranded wire (S) by frictional force.

Recently, PC steel wire (S) is manufactured using carbon steel having a certain surface hardness (normally HRC (Hardness Rockwell C): Rockwell hardness C scale) required for cable bridges, etc. A high-strengthened PC stranded wire (S) with an increased surface hardness of (S) is used.

However, as the wedge 30 is used as it is, unlike the relatively high-strengthened PC stranded wire (S), in the case of the PC stranded wire (S) with increased surface hardness, the PC stranded wire (S) by the screw groove of the wedge 30 While the engagement groove (A) formed on the outer circumferential surface is not sufficiently formed, there is a problem in that the fixing effect by the wedge 30 is reduced.

Accordingly, it is possible to secure the strength of the wedge 30 by various methods such as heat treatment, but at present, the strength of the wedge 30 (including the increase in surface hardness) has been increased because the limit of obtainable surface hardness has been reached. The method was also very limited, so there was inevitably a problem of wedge cracking and breakage when actually fixing the high-strengthened PC stranded wire (S).

Figure 1b shows an exemplary view of applying a cushioning material (6) between the conventional grip (Grip, 40) installation and PC stranded wire (S) and the wedge.

The conventional grip (Grip, 70) is a pipe member surrounding the entire outer circumferential surface of the PC stranded wire 10, and while penetrating the insertion hole 81 of the die, the diameter of the grip 70 is reduced while being compressed on the PC stranded wire 10. is the absence of being

At this time, the metal is plastically deformed by interposing the metal 40 as a sleeve between the PC stranded wire 10 and the grip (Grip, 70), and the grip (Grip, 70) is more effectively compressed to the PC stranded wire (10) It can be seen that it is possible to have .

However, this sleeve, the metal 40, is to be separately manufactured and inserted between the PC stranded wire 10 and the grip (Grip, 70), and the grip 70 is for enhancing the compression effect, so that the fixed end is attached to the end of the PC stranded wire. Although it is used as a tension band, it is not used as a tension end (an end that is fixed after tension).

Accordingly, in the case of the wedge 6 used for the tension end, referring to the right side view of FIG. 1b, various resin types of cushioning material 13 are injected between the PC stranded wire 10 and the PC stranded wire 10 while the cushioning material is hardened. It can be seen that the adhesive force of the wedge 6 and the wedge 6 are sufficiently secured.

Accordingly, it can be seen that the fixing effect of the wedge and the PC stranded wire can be enhanced by using the cushioning material 13 such as resin,

However, since the cushioning material 13 is a resin, it is not enough to solve the decrease in the fixing effect caused by the strengthening of the PS stranded wire, so the fixing effect of the wedge and the PC stranded wire is not strengthened even if the strength of the wedge itself is not strengthened according to the high strength of the PC stranded wire. It can be seen that there is a need for means to promote

0001) Korean Patent No. 10-0956799 (Title of the invention: wedge-shaped steel wire clamp, publication date: November 03, 2009) 0002) Japanese Patent No. 399708 (Title of the invention: fixing method of PC steel, publication date: July 27, 2007) 0003) Japanese Patent Laid-Open Patent No. 2000-345656 (Title of the invention: Compression grip of PC steel, publication date: December 12, 2000)

Accordingly, the present invention is to fix the PC stranded wire effectively in the anchorage without using a high-strength wedge in response to this in order to fix the high-strengthened PC stranded wire in order to fix the high-strengthened PC stranded wire after tensioning using a wedge in the anchoring hole formed in the anchoring hole. It is a technical task to solve the provision of a friction type wedge and its construction method that can be used.

In addition, rather than being used separately from the wedge, friction-type wedges that are formed integrally with the wedge to enhance the fixing effect are used, and friction-type wedges that do not otherwise affect workability and workability in the fixing operation of the PC stranded wire and the provision of its construction method as a technical problem to be solved.

The friction-type wedge of the present invention for achieving the above object and its construction method include: a friction-type wedge inserted into a fixing hole of an anchorage to fix a PC stranded wire in the anchoring hole, a plastic deformation material formed on the inner surface of a piece; and a surface protruding friction material integrated with the plastic deformable member, wherein the surface protruding friction material is bitten by the PC stranded wire while plastically deforming during the fixing process of the PC stranded wire to secure frictional force, and the frictional force is, In the fixing process of the PC stranded wire, the surface protruding friction material is in direct contact with the outer peripheral surface (surface) of the PC stranded wire, and frictional force is generated first. It is plastically deformed in a direction that resists the direction of action, and when the final plastic deformation is completed, the surface protruding friction material is simultaneously bitten and inserted into the outer peripheral surface of the friction-type wedge and PC stranded wire, and frictional force is generated secondarily to exert a fixing effect, and the surface The protruding friction material and the plastic deformable material are mixed with each other and then heated to melt the plastic deformable material with a low melting point first, and the surface protruding friction material and the plastic deformation material are mixed with each other. Formed by coating on the inner surface, the surface protruding friction material is a friction material in the form of particles having a higher melting temperature than a plastic deformation material and higher than the surface hardness of a PC stranded wire, and includes tungsten carbide particles or alumina-based particles And, the plastically deformable material is to include low-carbon steel as a metal material that can be plastically deformed by the tension force in the fixing process.

According to the friction wedge of the present invention and its construction method, in the fixing process of the PC stranded wire, the surface protruding friction material is bitten in direct contact with the outer circumferential surface (surface) of the PC stranded wire, and frictional force is generated primarily, and in the fixing process by the introduced prestress The surface protruding friction material integrated with the plastic deformation material is plastically deformed in a direction that resists the applied prestress action direction, and when the final plastic deformation is completed, the surface protruding friction material is simultaneously bitten and inserted into the outer peripheral surface of the friction wedge and PC steel wire, resulting in frictional force This secondary occurrence makes it possible to exert a fixing effect regardless of the strength or surface hardness of the slice.

In addition, the friction wedge of the present invention can be effectively integrated into the friction wedge by using the fact that the melting temperature of the protruding surface friction material is lower than the melting temperature of the plastic deformation material so that the protruding surface friction material integrated with the plastic deformation material can be integrated as a friction body. This will ensure the efficiency and economic feasibility of manufacturing.

Figure 1a is an exemplary view of fixing by a conventional PC stranded wire (S) and wedge)
Figure 1b is an example of a conventional grip (Grip) installation and an example of applying a cushioning material between the PC stranded wire (S) and the wedge,
Figures 2a, 2b and 2c is a configuration example of the friction wedge of the present invention and an example of installation of the anchorage,
Figures 3a and 3b is an exemplary view of the friction wedge construction method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement them. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

[The present invention friction type wedge 100]

2a, 2b and 2c is an exemplary configuration view of the friction wedge 100 of the present invention and an exemplary view of the anchorage installation.

Referring to FIG. 2C , the friction-type wedge 100 is obtained by integrating a plastic deformation material 130 and a surface protruding friction material 140 integrated into a cut piece 110 (wedge body), and the friction-type wedge 100 includes a plurality of The fragments of are bound by a binding ring 120,

The friction-type wedge 100 is installed to surround the outer peripheral surface of the PC stranded wire 210 , and after tensioning the PC stranded wire 210 , it is fixed while inserting it into the fixing hole 230 formed in a plurality of the anchoring holes 220 .

At this time, the friction body formed in the fragment of the friction wedge 100 of the present invention is higher than the melting temperature of the plastic deformation material (eg, steel; around 1580 ° C) than the melting temperature of the surface protruding friction material (eg, CBN (cubic boron nitride, boron) Small, 1900°C or higher) or cemented carbide powder with high WC (Tungsten carbide, 2870°C), mix the two materials to form a friction body and attach it to the wedge surface.

Alternatively, with the particle mixing plating technology, the plating solution in which the plastic deformation material ions and the surface protruding friction material are mixed can be formed directly on the wedge surface as a friction material of a certain thickness using a surfactant.

By the plastic deformation material 130 protruding from the surface protruding friction material 140, the PC stranded wire 210 can be more effectively fixed to the anchorage 220 regardless of the strength or surface strength of the slice 110.

The fixing device 200 of the present invention as described above includes a PC stranded wire 210 , an anchoring hole 220 , and a fixing hole 230 .

First, referring to FIG. 2c , the PC stranded wire 210 is made by twisting a plurality of strands and is tensioned using a tension device, and then the fixing hole 230 of the anchorage 220 using the friction wedge 100 . is settled in

The strands of the PC stranded wire 210 are manufactured using carbon steel or the like, and those having a certain strength and surface hardness are used.

Recently, as the high-strength PC steel wire 210 of 2200 to 2400Mpa is used for cable bridges between long spans, the surface hardness (usually expressed as HRC) also increases naturally.

Accordingly, if the wedge biting on the outer circumferential surface of the PC stranded wire 210 is not used with an increased surface hardness (or strength) in accordance with the high-strengthened PC stranded wire (high-strength wedge), the fixing effect is reduced due to the slip of the wedge during the fixing process. can be

However, as described above, there was a limitation in manufacturing the wedge according to the increase in strength of the current PC stranded wire 210 .

Next, referring to FIG. 2c , the anchor 220 is a horizontal plate to be embedded in the concrete structure 300 and is a steel material generally manufactured in a circular plate shape.

A plurality of fixing holes 230 are formed in the anchoring hole 220 in the form of a circular plate, and are formed to penetrate the anchoring hole 220 .

The anchorage 220 is set to be embedded in the concrete structure 300 including the cable bridge, but the anchorage hole 230 is exposed,

A friction-type wedge 100 installed to surround the PC stranded wire 210 inserted into the fixing hole 230 is inserted and installed,

After tensioning the PC lecture wire 210, when the tension is released,

As the friction wedge 100 is fixed in the fixing hole 230 , it serves to transmit the introduced prestress to the concrete structure 300 .

Next, the fixing hole 230 is shown in Figure 2c, referring to Figure 2c, the friction wedge 100 is inserted into the fixing hole 230 of the anchoring hole 220 to surround the PC stranded wire 210 withdrawn and installed in the anchoring hole 220. As a through hole to be fixed to the friction type wedge 100, it is formed as a tapering inner hole in which the diameter of one side is smaller than the diameter of the other side according to the shape.

Accordingly, while the friction wedge 100 is inserted into the tapered inner hole of the fixing hole 230 having a larger diameter, the friction wedge 100 is bitten on the outer peripheral surface of the PC stranded wire 210 and is fixed.

Accordingly, it can be seen that the inner surface of the friction-type wedge 100 is engaged with the outer peripheral surface of the PC stranded wire 210 , and the outer surface is formed to be engaged with the inner surface of the fixing hole 230 .

At this time, as shown in the lower drawing of FIG. 2A, the friction material, which is the surface protruding friction material 140 protruding from the surface of the plastically deformable material 130 of the present invention, is bitten on the outer peripheral surface of the PC stranded wire 210 with the bare wire exposed, and the PC stranded wire 210 ) When tensioned, the friction wedge 100 can naturally enter along the fixing hole (Self Anchor phenomenon),

As the tension gradually increases, plastic deformation of the plastic deformation member 130 occurs and contacts the PC stranded wire 210 and the friction-type wedge 100 body surface until the plastic deformation limit occurs, so that additional plastic deformation does not occur. , the friction body is cross-inserted into the surface of the PC stranded wire 210 and the friction wedge 100 to generate a friction force in the opposite direction to the tensile direction, thereby maximizing the anchoring effect of the wedge.

Accordingly, as shown in FIGS. 2A and 2B , the friction-type wedge 100 has a form in which a plurality of segments 110 are restrained by the binding ring 120 so that they can be installed around the outer circumferential surface of the PC stranded wire 210 .

At this time, referring to Fig. 1a, the inner surface of the conventional section is bitten to the outer circumferential surface of the PC stranded wire, and a screw groove is formed, and the screw groove is bitten to the outer circumferential surface of the PC stranded wire while the engagement groove (A) is formed and fixed in the anchoring hole of the anchorage. will make it

However, as the PC stranded wire 210 increases in strength, the surface hardness (or strength) of the wedge cannot keep up with it, so that the screw groove is not normally bitten on the outer peripheral surface of the PC stranded wire 210, and the fixing effect due to slip phenomenon is lowered. will occur

Accordingly, the present invention does not form a screw groove on the inner surface of the segment 110, as shown in FIGS. 2A and 2B, and the surface protruding friction material 140 integrated with the plastic deformation material 130 on the inner surface of the segment 110, That is, the friction body is integrated.

First, as shown in FIGS. 2A and 2B, the plastically deformable material 130 is a metal material that can be plastically deformed by tension during the fixing process, and may be low-carbon steel or an alloy including low-carbon steel, and has a constant melting temperature. Based on low carbon steel, the approximate melting temperature can be 1450°C.

Next, the surface protruding friction material 140 has a higher melting temperature than that of the plastically deformable material 130, as shown in FIGS. 2A and 2B, and is a friction material in the form of particles having a hardness higher than the surface hardness of the PC steel wire 210. It can be tungsten carbide particles used as cutting tools for machines, alumina-based particles used as abrasive tools, and the like. can be above 2200 °C.

Accordingly, when the surface protruding friction material 140 and the plastic deformation material 130 are heated by mixing with each other, the plastic deformation material 130 having a low melting point is melted first, and the surface projecting friction material 140 and the plastic deformation material 130 are melted first. ) is mixed with each other,

A plurality of surface protruding friction materials 140 can be applied to the inner surface of the slice 110 so that they can naturally protrude to the surface of the plastically deformable member 130 .

This application is performed on the outer peripheral surface (surface) of the PC stranded wire 210 by mixing the surface protruding friction material 140 and the plastic deformation material 130 melted by plasma spraying technology or nano cold application technology to a certain thickness. ,

The surface protruding friction material 140 protrudes from the surface of the plastically deformable material 130 in the form of particles, and after hardening, plastic deformation is possible by the applied stress.

That is, referring to FIG. 2A , it can be seen that the shape of the plastically deformable material 130 is naturally plastically deformed in the form of the outer peripheral surface of the PC stranded wire 210 by the applied stress, and the surface protruding friction material 140 is plastically deformed. It can be seen that the surface of the deformable material 130 is in contact with the outer peripheral surface of the PC stranded wire 210 to ensure frictional force.

That is, while the plastic deformation material 130 is deformed in a way that wraps the outer peripheral surface of the PC stranded wire 210 by the tension force, when the final plastic deformation is completed, the surface protruding friction material 140 is a friction-type wedge 100, PC stranded wire 210 ) is simultaneously bitten and inserted into the outer peripheral surface.

Accordingly, the surface protruding friction material 140 is in direct contact with the outer circumferential surface (surface) of the PC stranded wire 210 as shown in FIGS. 2a and 2b, and frictional force is generated primarily,

In the fixing process due to the introduced prestress, the surface protruding friction material 140 integrated with the plastic deformable material 130 is plastically deformed in a direction that resists the applied prestress action direction, and when the final plastic deformation is completed, the surface protruding friction material 140 It can be seen that the frictional wedge 100 and the PC stranded wire 210 are simultaneously bitten and inserted into the outer circumferential surface, and frictional force is generated secondarily.

[Friction type wedge 100 construction method of the present invention]

3a and 3b is an exemplary view of the friction wedge 100 construction method of the present invention.

The friction-type wedge 100 construction method is, as shown in FIGS. 3A and 3B, embedded in the concrete structure 300 and using the friction-type wedge 100 in the anchorage 220 where the anchoring hole 230 is exposed. (210) is a method of settling after tension.

First, as shown in FIG. 3A , the concrete structure 300 includes a cable anchoring end of a cable bridge, and the anchoring device 200 described above is buried and formed.

The fixing device 200 is formed to be embedded in the concrete structure 300 so that the fixing hole 230 is exposed, and the fixing hole 230 is pre-inserted with a PC stranded wire 210 so that the end is drawn out through the fixing hole 230 . will set it up.

At this time, the friction-type wedge 100 has a surface protruding friction material 140 formed with a constant thickness on the inner surface of the multiple slices 110, and a PC steel wire ( 210) is installed so as to be fixed to the anchoring port 220 regardless of the strength or surface strength of the slice 110, and to surround the PC stranded wire 210 by the binding ring 120.

Next, as shown in FIG. 3b, the drawn end of the PC stranded wire 210 is tensioned using a tension device (hydraulic jack, etc.) not shown, and the friction-type wedge 100 is inserted into the fixing hole of the anchorage 220 ( 230) While placing it at the beginning,

When the tension state is released, the PC stranded wire 210 is compressed by the reaction force and the friction-type wedge 100 is bitten by the fixing hole 230 and fixed, thereby prestressing the concrete structure 300 through the anchoring hole 220 . is introduced

At this time, in the fixing process, the friction material 140 protruding from the surface of the friction wedge 100 is bitten in direct contact with the outer circumferential surface (surface) of the PC stranded wire 210, and frictional force is generated primarily, and the plastic deformation material 130 is integrated. The surface protruding friction material 140 is plastically deformed in a direction that resists the applied prestress action direction, and the plastic deformation is integrated with the slice 110, thereby restraining the plastic deformation, and frictional force is generated secondarily to increase the strength or Regardless of the surface hardness, the required fixing effect can be exhibited.

The description of the present invention described above is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and likewise components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

100: friction wedge 110: intercept
120: binding ring 130: plastic deformation material
140: surface protrusion friction material 200: fixing device
210: PC stranded wire 220: anchorage
230: settlement hall 300: concrete structure

Claims (10)

A friction-type wedge 100 inserted into the anchoring hole 230 of the anchorage 220 to fix the PC stranded wire 210 in the anchoring hole 230,
A plastic deformation member 130 formed on the inner surface of the slice 110; and a surface protruding friction material 140 integrated with the plastic deformation member 130;
In the fixing process of the PC stranded wire 210, the plastic deformable material 130 is plastically deformed, and the surface protruding friction material 140 is bitten by the PC stranded wire 210 to secure frictional force,
The friction force is
In the fixing process of the PC stranded wire 210, the surface protruding friction material 140 is in direct contact with the outer circumferential surface (surface) of the PC stranded wire 210, and frictional force is generated primarily,
In the fixing process by the introduced prestress, the surface protruding friction material 140 integrated with the plastic deformable material 130 is plastically deformed in a direction that resists the applied prestress action direction, and when the final plastic deformation is completed, the surface protruding friction material 140 The frictional wedge 100 and the PC stranded wire 210 are simultaneously bitten and inserted on the outer peripheral surface, and frictional force is generated secondarily, thereby exhibiting a fixing effect,
The surface protruding friction material 140 and the plastic deformable material 130 are mixed with each other and then heated to melt the plastic deformable material 130 having a low melting point first, and the surface protruding friction material 140 and the plastic deformable material 130 are mixed with each other. While being mixed, a plurality of surface protruding friction materials 140 are formed by coating on the inner surface of the slice 110 so that they can protrude from the surface of the plastically deformable member 130, and the surface protruding friction material 140 is a plastically deformable material. (130) As a friction material in the form of particles having a higher melting temperature than the surface hardness of the PC stranded wire 210 as having a higher melting temperature, including tungsten carbide particles or alumina-based particles, the plastically deformable material 130, A friction-type wedge containing low-carbon steel as a metal material that can be plastically deformed by tension during the fixing process. delete delete delete delete delete delete (a) a plastic deformation member 130 formed on the inner surface of the slice 110; and a surface-projecting friction material 140 integrated with the plastic deformation material 130; in the process of fixing the PC stranded wire 210, the surface-projecting friction material 140 is directly on the outer peripheral surface (surface) of the PC stranded wire 210. The frictional force is first generated by contact with the introduced prestress, and the surface protruding friction material 140 integrated with the plastic deformable material 130 during the fixing process by the introduced prestress is plastically deformed in a direction that resists the introduced prestress action direction, and the final plasticity When the deformation is completed, the surface protruding friction material 140 is simultaneously bitten and inserted into the outer peripheral surface of the friction-type wedge 100 and the PC stranded wire 210. providing; and
(b) inserting the friction-type wedge 100 into the anchoring hole 230 of the anchoring hole 220 to fix the PC stranded wire 210 in the anchoring hole 230;
The protruding surface friction material 140 and the plastically deformable material 130 in step (a) are mixed with each other and then heated to melt the plastic deformable material 130 having a low melting point first, while the surface protruding friction material 140 and the plastically deformable material are first melted. 130 is formed by coating on the inner surface of the slice 110 so that a plurality of surface protruding friction materials 140 can protrude to the surface of the plastically deformable member 130 while mixing with each other,
The surface protruding friction material 140 of step (a) has a higher melting temperature than the plastic deformation material 130 and is a friction material in the form of particles having a hardness higher than the surface hardness of the PC steel wire 210, and tungsten carbide particles or alumina-based particles,
The plastic deformation member 130 is a friction-type wedge construction method comprising a low-carbon steel as a metal material that can be plastically deformed by the tension force in the fixing process. delete 9. The method of claim 8,
The friction-type wedge construction method in which the friction-type wedge 100 of step (a) is fixed to the anchorage 220 for the introduction of prestress into the concrete structure 300 including the cable bridge.

Images