Composite reinforcing bar equipped with split FRP sleeves

Abstract

The reinforcing bar having a field-assembled split FRP sleeve according to the present invention comprises a split FRP sleeve installed to surround the outer surface of a reinforcing bar, a resin injection channel (210) formed penetrating one side of the split FRP sleeve (200), one or more resin flow channels (220) formed on the inner surface of the split FRP sleeve (200) to maintain the movement of the injected resin, an air outlet (240) formed on the other side of the split FRP sleeve (200) where the resin injection channel (210) is formed, and a low-viscosity epoxy resin (230) injected through the resin injection channel (210) and moving along the resin flow channel (220) to fill the space between the reinforcing bar (100) and the split FRP sleeve (200).

Description

Technology Field

[0001] The present invention relates to a composite reinforcing bar that reinforces steel bars using a field-assembled split FRP sleeve, and a method for reinforcing the composite reinforcing bar. Background Technology

[0003] Patent inventions 001 and 002 have a technical relationship with the present invention in that they are inventions that reinforce rebar by wrapping FRP around the outside of a core material. However, while patent inventions 001 and 002 are made by wrapping FRP around the outside of a core material during the manufacturing process, the present invention does not include a technology that describes or incorporates the technical concept of forming a reinforcement part by partially covering it at the site in the same or similar manner. Prior art literature

[0005] (Patent Document 0001) KR 10-2554753 B1 (Registration Date July 07, 2023)(Patent Document 0002) KR 10-0709292 B1 (Registration Date April 12, 2007) The problem to be solved

[0006] The present invention aims to solve the problems associated with conventional rebar reinforcement technology by improving the limitations of application and high manufacturing and transportation costs of FRP composite reinforcing bars that can only be manufactured in a factory, and by providing a construction technology that enables the direct reinforcement of general rebar on-site.

[0007] In addition, by uniformly filling the resin using split FRP sleeves and resin flow channels, the occurrence of voids is minimized, and the integrity between the rebar and the FRP sleeve is improved, thereby increasing corrosion resistance, durability, and impact resistance.

[0008] In addition, the invention provides a field-assembled rebar reinforcement system and construction method that improves constructability and reduces construction and maintenance costs by allowing selective reinforcement of only the necessary sections without replacing existing rebar. means of solving the problem

[0010] To solve the above problem, the present invention provides a rebar reinforcement system that integrates the rebar and the FRP sleeve by installing a segmented FRP sleeve, which can be assembled on-site, on the outer surface of the rebar and uniformly injecting a low-viscosity curable resin through a resin flow channel formed on the inner surface of the FRP sleeve.

[0011] The above FRP sleeve is formed of glass fiber reinforced plastics (hereinafter referred to as GFRP), and a spiral or grid-shaped resin flow channel is formed on the inner surface to induce smooth flow of the injected resin.

[0012] In addition, a resin injection port is formed on one side of the sleeve and an air exhaust port on the other side to effectively discharge internal air, thereby minimizing the occurrence of voids and enabling uniform filling of the resin.

[0013] In addition, elastic sealing packings are provided at both ends to prevent resin leakage, and after curing, the rebar and FRP sleeve are firmly integrated, improving corrosion resistance, adhesion, and impact resistance. Effects of the invention

[0015] The present invention utilizes an FRP sleeve (200) to selectively reinforce only specific stress areas at the construction site, thereby improving construction performance compared to conventional technology where reinforcing bars are manufactured in a factory. Furthermore, since the structure does not wrap the entire reinforcing bar but selectively reinforces only specific stress areas such as the ends of the reinforcing bar, anchorage areas, or salt damage sections, it can provide the effect of reducing costs and improving construction performance.

[0016] In particular, it is possible to provide a rebar reinforcement system that allows for the rapid and economical reinforcement of existing rebar on-site and is suitable for application to structures where corrosive environments are a concern, such as tram stations, sound barriers, bridges, and coastal structures. Brief explanation of the drawing

[0018] FIG. 1 is an exploded perspective view of an FRP sleeve according to the present invention. FIG. 2 is a cross-sectional view of an FRP sleeve according to the present invention. Specific details for implementing the invention

[0019] Hereinafter, the most preferred embodiment of the present invention is described in detail to enable a person skilled in the art to easily practice the present invention. The configurations presented in the embodiments may be extended to objects that produce the same purpose and effect. Sub-concepts of the configurations presented in the embodiments may be considered implicit even if not explicitly stated.

[0020] The present invention relates to a reinforcing bar and a reinforcing method for reinforcing steel bars using a self-sealing FRP sleeve at the construction site.

[0021] Specifically, the process consists of the steps of installing a reinforcing bar (100) at the site, attaching an open FRP sleeve (200) to the reinforcement area, locking the open FRP sleeve (200) so that it surrounds the reinforcing bar, and then filling resin between the reinforcing bar (100) and the open FRP sleeve (200) to complete the composite reinforcing bar.

[0022] The open FRP sleeve (200) is formed in a shape that is not a circular tube but a circular shape divided in half, and is formed to be locked when wrapped around a reinforcing bar, thereby enabling construction without dismantling the reinforcing bar.

[0023] The open FRP sleeve (200) can be formed with a semicircular cylindrical cross-sectional shape of '⊂''⊃'.

[0024] At this time, one side of a pair of semicircular cylindrical sleeves of the open FRP sleeve (200) may be rotatably connected by a hinge (201), and the other side may be formed with a locking part (202) so as to be connected after wrapping around a reinforcing bar.

[0025] The locking part may be selected from known joining methods, but a groove may be formed on one side and a protrusion on the other side at each end of the semicircular cylindrical sleeve of the open FRP sleeve (200) and joined by fitting, or a groove or protrusion may be formed at the end of the semicircular cylindrical sleeve instead of a hinge and joined by fitting into the protrusion or groove at the end of the semicircular cylindrical sleeve on the other side.

[0026] In another embodiment, the groove and the protrusion may be formed with a repeating square or triangular shape so that one side and the other side can be fitted together like a puzzle.

[0027] When a semicircular cylindrical sleeve is formed by a bonding method in which the resin injected thereafter hardens after being inserted, construction convenience is improved and the manufacturing cost of the open FRP sleeve (200) is reduced.

[0028] After the open FRP sleeve (200) is joined to surround the rebar, the resin can be spread uniformly inside the FRP sleeve (200) through the resin injection channel (210) formed in the FRP sleeve (200).

[0029] The resin, which is uniformly spread inside the reinforcing bar (100) and the FRP sleeve (200), fills the space between the reinforcing bar (100) and the split FRP sleeve (200), thereby integrating the reinforcing bar (100) and the FRP sleeve (200) to complete the composite reinforcing bar.

[0030] The resin injected through the resin injection channel (210) can be formed into a microchannel so that it can spread uniformly inside the FRP sleeve (200) through the resin flow channel (220).

[0031] As the resin spreads uniformly inside the FRP sleeve (200) through the microchannels of the resin flow channel (220), the reinforcing bar and the FRP sleeve (200) become integrated without leaving an air layer between the FRP sleeve (200) and the reinforcing bar (100).

[0032] The resin flow channel (220) is formed to create a micro-space of about 0.5 to 2 mm between the rebar and the FRP sleeve (200) so that the resin flows along the space. At this time, to prevent air bubbles or empty spaces from forming when the resin spreads between the rebar and the FRP sleeve (200), it may be formed in a spiral helical shape inside the FRP sleeve (200). Since the resin flow channel (220) is formed as a micro-irregular irregularity in a spiral helical shape inside the FRP sleeve (200), the resin can move along the spiral groove and spread uniformly over the entire length, thereby increasing the mechanical bonding performance with the rebar, preventing the resin from slipping, and increasing the bonding surface area. To this end, it is preferable that the resin flow channel (220) be formed in a micro-irregular irregularity in a spiral helical shape with a height of 0.3 to 1.0 mm.

[0033] At this time, in order to spread the resin more evenly throughout the entire interior of the FRP sleeve (200), it is preferable to form an air outlet (240) on the opposite side of the sleeve where the resin injection channel (210) is formed.

[0034] It is preferable that both ends of the FRP sleeve (200) be sealed with packing. Since both ends of the FRP sleeve (200) are sealed with packing (300), the movement of resin and the discharge of air can be made more smooth.

[0035] The packing may be made of a closed circular material having elasticity and installed in advance before the FRP sleeve (200) is joined to the reinforcing bar to seal both ends of the FRP sleeve (200), or it may be provided as a tape-shaped packing material having elasticity so as to wrap around and seal the FRP sleeve (200) after it is joined to the reinforcing bar.

[0036] FRP sleeve (200) is preferably composed mainly of glass fiber and vinyl ester resin so that it has a relatively similar elastic modulus to reinforcing steel, does not corrode, and has an electrical insulation effect.

[0037] In particular, to selectively reinforce specific stress zones on-site, such as in sound barriers, and to provide a shock-absorbing layer, using vinyl ester rather than epoxy is advantageous in terms of flame and water resistance and crack resistance, and can provide sufficient performance in environments such as those involving de-icing agents in winter.

[0038] Therefore, the FRP sleeve (200) is preferably made of glass fiber reinforced plastics (hereinafter referred to as GFRP) having a vinyl ester resin as a matrix and containing E-Glass fibers or AR-Glass fibers, and is composed of 65 to 75 weight% glass fibers, 23 to 33 weight% vinyl ester resin, and 2 to 5 weight% additives.

[0039] It is preferable that the injected resin be composed of a low-viscosity epoxy with a viscosity of 400 to 900 cP so that it can easily move along the resin injection channel (210) and penetrate between the reinforcing bars without empty spaces, reduce bubbles, improve adhesive strength, reduce fatigue cracks, and improve impact resistance.

[0040] Therefore, it is preferable that the injected resin consists of 70-85 weight% low-viscosity epoxy, 10-20 weight% amine-based curing agent, 3-8 weight% rubber-based reinforcing agent (Toughener), and 1-5 weight% silica.

[0041] When performing on-site construction to selectively reinforce only specific stress areas and reinforce the rebar including a shock-absorbing layer using such an FRP sleeve (200), the adhesive strength between the rebar (100) and the FRP sleeve (200) can be greatly increased by reinforcing the rebar by applying a silane primer after the unpainted surface of the rebar is shot-blasted or phosphate-treated, then attaching the FRP sleeve (200) and injecting resin. Explanation of the symbols

[0043] 100 : Rebar 200 : FRP Sleeve 201: Hinge 202: Locking part 210 : Resin injection channel 220 : Resin flow channel 230 : Resin 240 : Air vent 300 : Packing

Claims

Claim 1 A composite reinforcing bar equipped with a divided FRP sleeve, characterized by comprising: a reinforcing bar (100); a divided FRP sleeve (200) installed to surround the outer surface of the reinforcing bar; a resin injection channel (210) formed through one side of the divided FRP sleeve (200); one or more resin flow channels (220) formed on the inner surface of the divided FRP sleeve (200) to maintain the movement of the injected resin; an air outlet (240) formed on the other side of the divided FRP sleeve (200) where the resin injection channel (210) is formed; and a low-viscosity epoxy resin (230) injected through the resin injection channel (210) and moving along the resin flow channel (220) to fill the space between the reinforcing bar (100) and the divided FRP sleeve (200). Claim 2 A composite reinforcing bar having a divided FRP sleeve according to claim 1, wherein the divided FRP sleeve (200) is formed by including a glass fiber reinforced plastic comprising a vinyl ester resin and 65 to 75 weight percent of glass fiber, and a spiral helical resin flow channel (220) with a height of 0.3 to 1.0 mm is formed on the inner surface. Claim 3 A composite reinforcing bar having a split FRP sleeve according to claim 2, wherein the low-viscosity epoxy resin has a viscosity of 400 to 900 cP and includes a rubber-based reinforcing agent (Toughener) to improve impact resistance after curing, and elastic sealing packings are provided at both ends of the split FRP sleeve (200) to prevent leakage of the resin and to discharge internal air to integrate the reinforcing bar and the FRP sleeve.

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