WO2015076429A1

WO2015076429A1 - Steel bar with fixing head and manufacturing method therefor

Info

Publication number: WO2015076429A1
Application number: PCT/KR2013/010582
Authority: WO
Inventors: 이재호
Original assignee: (주)세종알앤디; 이재호
Priority date: 2013-11-20
Filing date: 2013-11-20
Publication date: 2015-05-28

Abstract

The present invention provides a steel bar with a fixing head, which is used for reinforced concrete or steel frame reinforced concrete structures, and a manufacturing method therefor. In a steel bar (10) with a fixing head, a steel bar deformation part (40) having a cross sectional perimeter greater than the cross sectional perimeter of a steel bar (30) is formed at the end of the steel bar (30) and fixed to a fixing plate (50), so that the working range of local bearing stress is relatively greater than in the conventional art and low stress is applied to the entire fixing head, thereby enhancing the fixing effect. The steel bar (10) with a fixing head is manufactured in a manner where the steel bar deformation part (40) is formed by molding the end of the steel bar (30) and then welding the end of the steel bar deformation part (40) to the fixing plate (50) which is formed by a separate machining or molding process, thereby improving manufacturing convenience and reducing manufacturing costs.

Description

Reinforcing bars equipped with a fixing head and a manufacturing method thereof

The present invention relates to a reinforcing bar provided with a fixing head and a method for manufacturing the same, and more specifically, to improve the fixing ability of reinforcing bars used in reinforced concrete or steel reinforced concrete structures, and to facilitate reinforcing bars. The present invention relates to a rebar provided with a fixing head and a method of manufacturing the same.

In general, the compressive force generated in the reinforced concrete structure, etc. are mainly received by the concrete, the tensile force can be simplified to be in charge of the reinforcement. In this case, the reinforcing bars must be settled in the concrete at an appropriate length to accommodate the tensile forces generated. In addition, when reinforcing bars are to be connected, the overlapping lengths of the connecting bars should be sufficiently secured.

The design criteria for such cases are presented internationally under the name 'Development and Splices of Reinforcement'. At this time, the fixing method of the reinforcing bar can be divided into bending anchorage (Bending Anchorage) and mechanical anchorage (Mechanical Anchorage) according to the geometric characteristics of the fixing portion. In addition, the joints of the reinforcing bars are used, such as the joints to secure the prescribed joint length, mechanical screw joints using reinforcing bars or couplers in the field.

1 is a view for explaining an example of the bending anchorage in the fixing method of the rebar.

Referring to FIG. 1, a representative example of the bending anchorage is defined as 90 ° {(a) of FIG. 1 (a)}, 135 ° ((b)} of the end 1 'of the reinforcing bar 1 to fix the reinforcing bar. It is a conventional system which bends in various angles, such as 180 degrees (FIG. 1 (c)), and reinforces in concrete.

In order to secure the anchoring capacity of the reinforcing bar, such bending anchorage must secure the anchoring length required by the design standards. However, such a bending anchorage has a problem in that the reinforcement work is very difficult in the part where the reinforcement is concentrated, and the reinforcement ability of the reinforcing bar is insufficient due to the inability of placing concrete due to the narrow reinforcing bar spacing.

2 is a view for explaining an example of a mechanical anchor in the fixing method of the rebar.

Referring to FIG. 2, the mechanical anchorage is typically anchored to concrete with a member having an end head called an anchor. Such a mechanical anchorage is generally achieved by coupling the head 2 that forms the anchor to the end of the rebar 1. In such a mechanical anchorage, the head 2 is joined to the end of the reinforcing bar 1 by friction welding (FIG. 2 (a)). The end of the reinforcing bar 2 is heated and pressurized in the axial direction to form a circular head ( 2) in one-piece form (FIG. 2B), in which a stud having a stem and a head is directly butt welded to a reinforcing bar, and a thread is provided at the end of the reinforcing bar 1. The form of screwing the nut which processes and head functions is proposed.

On the other hand, in relation to such mechanical anchorages, Republic of Korea Patent Publication No. 10-0907398 "Manufacturing method of reinforcing bar with a fixing head" is heated by heating the end region of the reinforcing bars, compressing the heated end region in the axial direction A method of manufacturing a reinforcing bar with a fixing head comprising a step of integrally forming an enlarged diameter portion that becomes a fixing head by performing hot upsetting to plastically deform so as to increase the outer diameter, wherein the temperature of the end region of the reinforcing bar is reduced in cross section. As it gets closer, it increases continuously or stepwise, the temperature of the part separated 2.0 axially from the rebar's cross-section is less than the melting point of the reinforcing material at 1300 ° C or more, and the temperature of the part separated 5.0 axially from the cross-section of the rebar. It proposes the technique of heating so that it may be more than Ac3 transformation point of reinforcing steel material to 1200 degrees C or less.

In addition, Korean Patent Publication No. 10-1122122 "Reinforcing bar connection device for head reinforcement" together with the upper and lower head reinforcement of the reinforced concrete beam is disposed at a certain angle on one side of the column head of the reinforced concrete column by concrete pouring construction In the reinforcing bar connecting device for connecting the head reinforcement, coupled to the upper and lower head reinforcement of a predetermined length disposed on one side of the reinforcement concrete pillar, locking head means for increasing the connection strength to the end side of the head reinforcement The technique to be equipped is proposed.

In addition, Korean Patent Laid-Open Publication No. 10-2011-0058622 "Wedge-type reinforcing bar fixing structure using a plate-shaped fixing member" is fixed to the wedge member of various forms on the protrusion of the deformed reinforcing bar, and also various outer peripheral edges of the wedge member There is proposed a technique for fixing the coupling member in the wedge type.

However, the bending anchorage and the mechanical anchorage according to the prior art have a limitation in improving the anchorage ability of the rebar because the local operating range of the local pressure stress can not be limited depending on the diameter of the reinforcement or the stem. And, there is a problem that the limit of such fixing capacity can not support the high strength of the head rebar.

The present invention is proposed to improve the problems of the prior art, a new that can improve the anchorage capacity of the reinforcing steel used in reinforced concrete (RC) or steel reinforced concrete (SRC) structure, etc. It is an object to provide a reinforcing bar provided with a fixing head of the form.

In particular, the present invention is able to form a cross-sectional circumferential length of the reinforcing bar in contact with the fixing head longer than the conventional method compared to the prior art to reduce the local pressure stress acting on the concrete to improve the anchoring capacity of the rebar It is an object to provide a reinforcing bar provided with a fixing head of the form.

In addition, an object of the present invention is to provide a reinforcing bar provided with a new type of fixing head to facilitate the reinforcing bars using the reinforcing bar provided with a fixing head.

In particular, the present invention by using a reinforcing bar provided with a fixing head to enable bolted coupling through the long hole even when the center axis of the two bars to be jointed when the reinforcing operation does not coincide, so that the reinforcement operation can be convenient An object of the present invention is to provide a reinforcing bar provided with a fixing head of a new type.

In addition, the present invention allows a relatively long cross-sectional length of the reinforcing bar in contact with the fixing head compared to the prior art to reduce the local pressure stress acting on the concrete to improve the fixing ability of the reinforcing bar In providing the reinforcing bar is provided, the object of the present invention is to provide a method for manufacturing a rebar provided with a new type of fixing head to increase the convenience of manufacturing.

According to a feature of the present invention for achieving the above object, the reinforcing bar 30; A reinforcing bar part 40 formed integrally with the reinforcing bar 30 at an end of the reinforcing bar 30 and having a cross-sectional perimeter length longer than the cross-sectional perimeter length of the reinforcing bar 30; A fixing plate (50) formed to have an area larger than the cross-sectional area of the rebar deformation portion (40) and fixed to an end of the rebar deformation portion (40); The cross sectional circumferential length of the end 42 of the rebar deformable portion 40 formed on the fixing plate 50 has a length longer than the circumferential circumferential length of the reinforcing bar 30 so that the local pressure stress acting on the concrete is increased. To be lowered.

In the reinforcing bar provided with the fixing head according to the present invention as described above, the reinforcing bar 40 is formed by changing the shape of the cross-section gradually from the end of the reinforcing bar 30, and the first forming part 41a, The shape of the cross section from the end of the first molding portion 41a to the end 42 of the rebar deformation portion 40 may be provided with a second molding portion 41b.

In the reinforcing bar provided with the fixing head according to the present invention, the first molding part 41a of the reinforcing bar 40 is formed to have a slope gradually reduced from the end of the reinforcing bar 30. ), And an upper and lower surface 43a formed to have an inclination gradually expanding from the end of the reinforcing bar 30, and the second molding part 41b of the reinforcing bar part 40 may include the first molding part ( Front and rear surfaces 42b, which are maintained in the same cross-sectional shape from the end of the front and rear surfaces 42a of 41a to the end 42 of the reinforcing bar portion 40, and the upper and lower surfaces 43a of the first molding portions 41a. The upper and lower surfaces 43b, which are maintained in the same cross-sectional shape, may be provided from the end of the bar to the end 42 of the rebar deformation unit 40.

In the rebar provided with a fixing head according to the present invention, the reinforcing bar 40 is disposed on the central axis with respect to the width (W) direction of the fixing plate 50, the fixing plate 50 is the reinforcing bar It is further provided with a bolt hole 56 formed to be disposed on both sides with respect to the deformable portion 40, it can be bolted through the bolt hole 56 when the reinforcing bar.

In the reinforcing bar provided with the fixing head according to the present invention, the bolt hole 56 is formed as a long hole having a long length on the central axis, the central axis is inclined at a predetermined angle with respect to the vertical direction, In case of reinforcing bar reinforcement, even if the central axis of the reinforcing bar is inconsistent, it can be easily combined.

According to another feature of the present invention for achieving the above object, in the method of manufacturing a rebar having a fixing head formed by connecting the fixing plate 50 to the end of the reinforcing bar 30, the end of the reinforcing bar 30 By pressing the reinforcing bars, the reinforcing bars 40 having a cross-sectional perimeter longer than the cross-sectional perimeter of the reinforcing bar 30 is formed integrally with the reinforcing bar 30 at the end of the reinforcing bar 30 Processing step; A fixing plate processing step of forming the fixing plate 50 as a flat plate so as to have an area larger than the cross-sectional area of the reinforcing bar deformation portion 40; The welding step of welding the end of the reinforcing bar 40 is fixed to the fixing plate 50.

In the method of manufacturing a rebar having a fixing head according to the present invention, the fixing plate processing step includes forming bolt holes 56 at both sides of the central axis with respect to the width (W) direction of the fixing plate 50. Further, in the welding step, the rebar deformable portion 40 may be disposed on the central axis with respect to the width W direction of the fixing plate 50 to be welded to the fixing plate 50.

According to the reinforcing bar provided with a fixing head according to the present invention and a manufacturing method thereof, the cross-sectional circumferential length of the end portion 42 of the reinforcing bar deformation portion 40 formed on the fixing plate 50 is the cross-sectional circumferential length of the reinforcing bar 30. The area of local pressure stress is increased by having a longer length so that the local pressure stress on the concrete of the fixing head is relatively lower than that of the prior art, and thus the anchoring performance of the reinforcing bar is very improved. Therefore, the construction is simpler and the reinforcing length of the reinforcing bar is much shorter than that of the conventional method of bending or mechanical fixing. In addition, since the fixing performance is improved compared to the prior art, it can be effectively used even in a higher strength reinforcing bar than the conventional mechanical fixing device. In addition, it is possible to bolt-bond both the reinforcing bars connected to the fixing plate 50 by forming a bolt hole 56, unlike the rebar is applied to the anchorage according to the prior art can be expected to have the advantage of easy reinforcement work in the field have. In particular, the reinforcing bar provided with the fixing head according to the present invention is a bolt hole 56 is formed as a long hole having a long length on the central axis, the central axis is inclined at a predetermined angle with respect to the vertical direction, Even when the central axis of the double reinforcing bar is inconsistent, the coupling is easy. In addition, the manufacturing method of the reinforcing bar provided with a fixing head according to the present invention forms a fixing plate 50 by cutting the plate provided in a variety of standards, it is easy and economical welding method with the reinforced bar (40) Etc.) to produce a reinforcing bar provided with a fixing head, and has the advantage of lowering the manufacturing cost while ensuring the convenience of manufacturing.

1 is a view for explaining an example of a bending anchorage in the fixing method of the rebar;

2 is a view for explaining an example of a mechanical anchor in the fixing method of the rebar;

Figure 3 is a perspective view for explaining a reinforcing bar with a fixing head and a method for manufacturing the same according to the spirit of the present invention;

Figure 4 is a side view for explaining the reinforcing bar with a fixing head according to the technical idea of the present invention by cutting a portion along AA 'of Figure 3 and a method of manufacturing the same.

5 is a perspective view for explaining a reinforcing bar provided with a fixing head and a method of manufacturing the same according to an embodiment of the present invention;

Figure 6 is a side view and a plan view for explaining the reinforcing bar with a fixing head and a method for manufacturing the same according to a preferred embodiment of the present invention;

7 is a view for explaining a rebar provided with a fixing head according to another embodiment of the present invention;

8 is a view for explaining the joint form of the reinforcing bar provided with a fixing head according to an embodiment of the present invention;

9 is a view for explaining the form of applying the bending anchorage and mechanical anchorage in the prior art and the operating range of the local pressure stress of the reinforcing bar provided with the anchoring head according to the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 3 to 9, and like reference numerals denote like elements for performing the same functions in FIGS. 3 to 9. On the other hand, in each drawing, it is easy for workers in this field from the general construction and operation of reinforcing bars, the technology of constructing reinforcing steel reinforcement or steel reinforcement concrete structures, the manufacturing technology of reinforcing steel, the technology for forming or processing reinforcing steel, and welding technology. Detailed descriptions of techniques that can be applied will be omitted. In addition, although the size ratio between elements is somewhat different in the drawings of the drawings, or the size between the parts that are coupled to each other is expressed differently, the representation differences in such drawings are easily understood by those skilled in the art. The descriptions are omitted since they are possible parts.

5 is a perspective view illustrating a reinforcing bar provided with a fixing head and a method of manufacturing the same according to a preferred embodiment of the present invention, and FIG. 6 illustrates a rebar provided with a fixing head and a method of manufacturing the same according to a preferred embodiment of the present invention. It is a side view and a top view for demonstrating. 6A is a front view of the reinforcing bar provided with the fixing head shown in FIG. 5, and FIG. 6B is a plan view of the rebar provided with the fixing head shown in FIG. 5. And, Figure 7 is a view for explaining a rebar provided with a fixing head according to another embodiment of the present invention.

5 and 6, the reinforcing bar 10 provided with the fixing head according to the preferred embodiment of the present invention includes a fixing plate having a reinforcing bar 30, a reinforcing bar part 40, and a fixing plate 50. The cross-sectional circumference of the end 42 of the reinforcing bar portion 40 formed on the 50 to have a length longer than the cross-sectional circumference of the reinforcing bar 30 to increase the area where the local pressure stress is applied, the prior art Compared to this, the local pressure stress on the concrete of the fixing head is relatively lowered, thereby improving the fixing performance of the reinforcing bar in the concrete.

In the present embodiment, the rebar deformation portion 40 is integrally formed with the rebar 30 at the end of the rebar 30. The rebar deformation portion 40 is gradually changed from the end of the reinforcing bar 30 having a circular cross section (cross section is the same as the cross section of the rebar), the cross-sectional circumference length longer than the cross-sectional circumference length of the reinforcing bar 30 It is formed to have. The end 42 of the rebar deformable portion 40 and the upper surface 52 of the fixing plate 50 have a flat surface and form an area in which the local pressure stress is applied. 42) and the welded angle of the upper surface 52 of the fixing plate 50 to form a right angle, to have a uniform welding surface when welding with the fixing plate 50 to make the welding stable and to facilitate the welding operation. To help. In addition, the height (H) of the fixing plate 50 and the end 42 of the reinforcing bar deformable portion 40 are formed to be the same to each other to facilitate the welding operation. In addition, the end portion 42 of the reinforcing bar deformable portion 40 formed integrally with the end of the rebar 30 is fixed to the fixing plate 50. At this time, the fixing plate 50 is formed to have an area (W × H, preferably 10 times or more) larger than the cross-sectional area of the reinforcing bar deformable part 40 and is fixed to the end of the rebar deforming part 40. Here, in the case where the fixing plate 50 has a smaller area than the cross-sectional area of the reinforcing bar portion 40, there is a problem that the fixing ability is almost lost.

As shown in FIG. 6, the reinforced deformation portion 40 has a gradual cross-sectional change through the first molding portion 41a, and a flat end portion 42 is formed through the second molding portion 41b. Be sure to Here, the first shaping portion 41a of the reinforcing bar 40 is formed to gradually change the shape of the cross-section from the end of the reinforcing bar 30 (at this time, as shown in (a) of FIG. 6, the reinforcing bar 30 ) area of the end ^{(a1 = πD 2/4)} , the first cross-sectional area of the forming section (41a) (a2 = h2 × w2) and a second cross-sectional area (a3 = h3 × w3 of the forming section (41b)) are the same} The shape of the cross-section of the second molding portion 41b from the end of the first molding portion 41a to the end 42 of the reinforcing bar portion 40 remains the same. In particular, the reinforcing bar 10 provided with the fixing head according to the present embodiment has a circular cross section at the end portion 42 of the reinforcing bar portion 40 while the first molded part 41a, which is mainly deformed, has a small change in abrupt cross section. The zone in which the local pressure stress of greater length than the outer circumferential length of the rebar 30 is applied is formed. That is, in the present embodiment, as shown in FIG. 6B, the first molding part 41a gradually decreases the slope w2 at which the front and rear surfaces 42a are gradually reduced from the end of the reinforcing bar 30. As shown in (a) of FIG. 6, the upper and lower surfaces 43a have an inclination (h2 gradually expanding) gradually expanding from the end of the reinforcing bar 30. On the other hand, the second molding portion 41b has a front and rear surface 42b having an end portion of the front and rear surfaces 42a of the first molding portion 41a so that the end portion 42 of the rebar deformation portion 40 has a flat surface. From the end of the upper and lower surfaces 43a of the first molding portion 41a to the end 42 of the first and second reinforcing portions 40a. Up to 42) in the same cross-sectional shape. That is, the cross-sectional size of the front and rear surfaces 42a constituting the width w3 and the upper and lower surfaces 43b constituting the height h3 is such that the second molding portion 41b has a reinforcing bar portion (from the end of the first molding portion 41a). It is formed to the same cross-sectional size up to the end 42 of the 40.

On the other hand, in the embodiment of the present invention, the rebar deformable portion 40 and the fixing plate 50 is preferably formed in a cross-section as described above for the convenience of manufacturing, as shown in Figure 7, in various forms Modifications can be applied, and modifications of this form will also be made under the technical idea of the present invention. For example, (a) of FIG. 7 shows an example in which the fixing plate 50 is formed of a rectangular plate material and the reinforcing bar portions 40 are formed crosswise (+) (40a, 40b). In addition, (b) of FIG. 7 forms the fixing plate 50 as a circular plate material, and the reinforcing bar portion 40 is formed radially from the center of the reinforcing bar 30 (40a, 40b, 40c, 40d, 40e, 40f). , 40g). In addition, in the present embodiment, the fixing plate 50 has shown an example of applying a plate of a single thickness, but such a fixing plate 50 may be applied to a plate of which the thickness is changed. Of course, this change in thickness will be on the opposite side of the weld face.

By the configuration of the reinforcing bar deformable portion 40 and the fixing plate 50, the reinforcing bar 10 provided with the fixing head according to the present embodiment is easier to construct than the conventional fixing method by the fixing or mechanical fixing device. Rebar settling length can be much shorter. In addition, since the fixing performance is improved compared to the prior art, it can be effectively used even in a higher strength reinforcing bar than the conventional mechanical fixing device.

On the other hand, the reinforcing bar 10 is provided with a fixing head according to a preferred embodiment of the present invention has a configuration of the fixing head, as shown in Figure 8, through bolting (bolting) by the bolt (90) and nut Reinforcing bar is characterized in that it is possible to.

To this end, in the fixing plate 50 of the reinforcing bar 10 provided with the fixing head according to the present embodiment, as shown in FIG. 5, a bolt hole 56 is formed. In particular, in the present embodiment, the reinforcing bar portion 40 is disposed on the central axis with respect to the width W direction of the fixing plate 50 to be fixed to the fixing plate 50, and the bolt hole of the fixing plate 50 is formed. 56 is disposed on both sides with respect to the bar deformation portion 40 (wherein, the bolt hole 56 may be disposed symmetrically or asymmetrically with respect to the width W direction of the fixing plate 50). When the reinforcing bar is connected to the central axis of the reinforcing bar 30, bolting 56 is used to secure bolting and the construction of the reinforcing bar by joining the bolt 90 and the nut (not shown).

8 is a view for explaining the joint form of the reinforcing bar is provided with a fixing head according to an embodiment of the present invention, Figure 8 (a) is a double reinforcing bar with a bolt 90 by applying a long bolt hole 56 8 (b) is a view for explaining the action of the bolt hole 56 when the bolt 90 is coupled.

As shown in Fig. 8, in this embodiment, the bolt hole 56 is formed as a long hole having a long length on the central axis (refer to the central axis of the bolt hole 56), the vertical direction (fixing plate 50) Since the central axis is formed to be inclined at a predetermined angle with respect to the reference}, even when the central axis of the positive reinforcing bars are inconsistent, the coupling is easy.

Therefore, the reinforcing bar 10 provided with the fixing head according to the present embodiment can be easily connected to the reinforcing bar in the field, unlike the reinforcing bar to which the fixing device according to the prior art is applied.

The method for manufacturing a rebar having a fixing head according to a preferred embodiment of the present invention as described above forms a fixing plate 50 by cutting a plate provided in various standards, and welds the reinforcing bar 40 to the reinforcing bar 40. It is characterized in that the manufacturing cost can be lowered while ensuring the convenience of manufacturing by manufacturing a rebar provided with a fixing head formed by connecting the fixing plate 50 to the end of 30).

More specifically, the method of manufacturing a rebar having a fixing head according to the present embodiment includes a rebar deformation part processing step, a fixing plate processing step, and a welding step. At this time, the rebar deformation part processing step by pressing the end of the reinforcing bar 30, the rebar deformation unit 40 having a cross-sectional circumferential length longer than the cross-sectional circumferential length of the reinforcing bar 30 is the rebar ( 30) to be integrally formed. In the fixing plate processing step, the fixing plate 50 is formed of a flat plate to have an area (W × H, preferably 10 times or more) larger than the cross-sectional area of the reinforcing bar portion 40. In this case, the bolt hole 56 is formed to be symmetrical to both sides of the central axis with respect to the width (W) direction of the fixing plate 50 to facilitate reinforcing the reinforcement through bolting later. The rebar deformable portion 40 and the fixing plate 50 separately prepared as described above are completed by welding the ends of the rebar deforming portion 40 to be fixed to the fixing plate 50. At this time, in this embodiment, the rebar deformable portion 40 is disposed on the central axis with respect to the width W direction of the fixing plate 50 to be welded to the fixing plate 50. In the present embodiment, the end 42 of the rebar deformable portion 40 is fixed to the fixing plate 50 by welding. Various types of welding, such as electric resistance welding and friction welding, as well as general arc welding may be applied. .

9 is a view for explaining the form of applying the bending anchorage and mechanical anchorage in the prior art and the operating range of the local pressure stress of the reinforcing bar provided with the anchoring head according to the present invention. At this time, Figure 9 (a), as shown in Figure 1, when the bending anchorage is formed by bending the end (1 ') of the reinforcing bar 1 is applied shows a working range (L1) of the local pressure stress, Figure 9 (b) shows the operating range (L2) of the local pressure stress when a mechanical anchorage formed by joining the head 2 to the end of the reinforcing bar 1 by friction welding is applied as shown in FIG. 9 (c) is applied to a mechanical anchorage in which an end of the reinforcing bar 2 is heated and pressurized in an axial direction to generate a circular head 2 integrally, as shown in FIG. 2 (b). When the local pressure of the working area (L3) is shown, Figure 9 (d) shows the operating range of local pressure stress (L4) when the reinforcing bar is provided with a fixing head according to a preferred embodiment of the present invention Is showing.

Referring to FIG. 9, the fixing ability of the bending reinforcement method (applied bending anchorage) and the reinforcement method with anchor head (applied mechanical anchorage) is closely related to the local pressure stress acting on the concrete. In general, when looking at the fixing process by the fixing mechanism (mechanism) of the reinforcement reinforced in reinforced concrete or steel reinforced concrete structure, first, the concrete acupressure is generated under the anchorage (Anchorage). That is, as shown in Figure 9, the tensile force is applied in the reinforcement (1) direction (arrow direction), the concrete acupressure stress is generated under the anchorage (Anchorage). As the tensile force increases, the concrete local pressure stress rises, and the concrete local pressure breakage occurs (in particular, in the areas L1, L2, L3, and L4). At this time, a slip is generated in the anchorage. If the anchoring of the reinforcing bars is not stable, cracks are generated in the concrete of the anchorage, which leads to expansion and destruction of concrete cracks. .

At this time, as shown in Fig. 9 (a), the bending reinforcement method has a high local acupressure inside the bent portion such that the operating range (L1) of the local pressure stress is less than half (0.5πD) of the cross-sectional perimeter length of the reinforcing bar (1) Structural weaknesses that produce stress require additional reinforcement of reinforcing bars or through reinforcing bars (partial mechanical anchorage). This requires a relatively long anchorage length to reinforce the adhesion. In addition, it may be accompanied by a construction inconvenience to wrap around the flexural rebar.

In addition, in the case of fixing using reinforcing bars having anchor heads as shown in FIGS. 9B and 9C, since the working ranges of the local pressure stress L2 and L3 are the same as the cross-sectional circumferential length? D, Since the local pressure stress generated in the lower stress acts in comparison with the above-described bending rebar method, the relatively short reinforcement length has sufficient anchoring effect, but the local pressure stress has a range of action of the reinforcing bar (or stem of the stud). It is determined by the cross-sectional perimeter length (πD), thereby limiting the improvement of the fixing ability.

On the other hand, the reinforcing bar 10 provided with the fixing head according to the preferred embodiment of the present invention, the operating range (L4) of the local pressure stress of the reinforcing bar deformable portion 40 so as to have about 2πD twice the circumferential length of the rebar cross section. The cross-sectional circumferential length (here 2H) (the cross-sectional circumferential length of the end 42 of the reinforcing bar deformable portion 40) can be increased. For example, in the case of the D22 rebar (cross section a1 = 3.871 cm ² ), the cross sectional perimeter length is πD = 6.9 cm. On the other hand, when the shape of the cross section of the reinforced bar portion 40 according to the present invention is h3 × 3 (= 6.9cm × 0.561cm; cross-sectional area a3 = 3.871cm ² ), the operating range L4 of the local pressure stress is 2H ( = 2 x 3 = 2 x 6.9), it can be understood that the circumferential length of the cross section is doubled while having the same cross-sectional area. In this way, increasing the circumferential length of the cross section relatively alleviates the local pressure stress acting on the concrete, thereby further improving the fixing performance.

As described above, the rebar with a fixing head according to a preferred embodiment of the present invention and a manufacturing method thereof are shown in accordance with the above description and drawings, but this is merely described for example and does not depart from the spirit of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope.

3 is a perspective view illustrating a reinforcing bar provided with a fixing head and a method of manufacturing the same according to the technical idea of the present invention, and FIG. 4 is a part cut along the line AA ′ of FIG. It is a side view for demonstrating the rebar provided with the fixing head, and its manufacturing method.

3 and 4, the reinforcing bar 10 provided with the fixing head according to the present invention basically has an end of the reinforcing bar 30 having a circular cross section whose length is longer than the cross-sectional perimeter of the reinforcing bar 30. By forming the reinforcement deformation portion 40 having a circumferential length so as to be fixed to the fixing plate 50, the local area of the local pressure stress has a relatively large size compared to the prior art so that the overall low local to the concrete in the fixing head Acupressure stress is characterized in that to increase the fixing effect.

The reinforcing bar 10 provided with the fixing head according to the present invention includes a reinforcing bar 30, a reinforcing bar part 40, and a fixing plate 50. Here, the reinforcing bar 30 is a general reinforcing bar used in a reinforced concrete structure or steel reinforced concrete structure. Reinforcing bar 40 is formed integrally with the reinforcing bar 30 at the end of the reinforcing bar 30, it is formed to have a cross-sectional peripheral length longer than the cross-sectional peripheral length of the reinforcing bar 30. Such rebar deformation portion 40 is formed into a thin plate shape by pressing the end of the rebar 30 having a circular cross section is formed integrally with the rebar 30. In addition, the fixing plate 50 is formed to have an area (W × H, preferably 10 times or more) larger than the cross-sectional area of the rebar deformation portion 40 and is fixed to the end 42 of the rebar deformation portion 40.

The reinforcing bar 10 having the fixing head according to the present invention has a cross-sectional perimeter of the end 42 of the reinforcing bar 40 formed on the fixing plate 50 than the cross-sectional perimeter of the reinforcing bar 30. By having a long length, the area under which the local pressure stress is applied is increased to improve the anchoring performance of the reinforcing bar in the concrete.

Reinforcing bar 10 equipped with a fixing head according to the present invention preferably forms the end of the reinforcing bar 30 to form a reinforcing bar 40, and then separately processed (cutting the plate material provided to a constant size typically) Or it is manufactured by welding the end of the reinforced bar portion 40 to the fixing plate 50 formed by molding (forging or pressing). Of course, the method of forming the fixing head by fixing the end portion of the reinforcing bar deformable portion 40 to the fixing plate 50 may be a method of integrally molding using a single material, but fixing according to the present invention. Reinforcing bar 10 provided with a head is preferably formed to the end of the reinforcing bar 30 to form a reinforcing bar deformable portion 40, so as to increase the convenience of manufacturing and lower the manufacturing cost, and separately formed fixing plate 50 To weld the two components together.

As described above, the reinforcing bar provided with the fixing head according to the present invention and a method for manufacturing the same have a fixing head different from the conventional technology in which a range of local pressure stress is automatically determined (rebar or stem circumferential length) when the diameter of the reinforcing bar is determined in common. By increasing the cross-sectional periphery of the end portion 42 of the reinforcing bar 40 to alleviate the local pressure stress to further improve the fixing ability.

Reinforcing bars with a fixing head and a method for manufacturing the same according to the present invention are used in reinforced concrete or steel reinforced concrete structures.

Claims

Reinforcing bar 30;

A reinforcing bar part 40 formed integrally with the reinforcing bar 30 at an end of the reinforcing bar 30 and having a cross-sectional perimeter length longer than the cross-sectional perimeter length of the reinforcing bar 30;

A fixing plate (50) formed to have an area larger than the cross-sectional area of the rebar deformation portion (40) and fixed to an end of the rebar deformation portion (40);

The cross sectional circumferential length of the end 42 of the rebar deformable portion 40 formed on the fixing plate 50 has a length longer than the circumferential circumferential length of the reinforcing bar 30 so that the local pressure stress acting on the concrete is increased. Reinforcing bar provided with a fixing head, characterized in that to be lowered.
The method of claim 1,

The reinforcing bar portion 40 is the first molding portion (41a) is formed so that the shape of the cross-section gradually from the end of the reinforcement 30,

A fixing head comprising a second molding portion 41b having the same cross-sectional shape from the end portion of the first molding portion 41a to the end portion 42 of the rebar deformation portion 40. Equipped rebar.
The method of claim 2,

The first molding portion 41a of the reinforcing bar 40 is a front and rear surface 42a formed to have an inclination gradually decreasing from the end of the reinforcing bar 30,

An upper and lower surface 43a formed to have an inclination gradually expanding from an end of the reinforcing bar 30,

The second molded part 41b of the rebar deformable part 40 has the same cross-sectional shape from the end of the front and rear surfaces 42a of the first molded part 41a to the end 42 of the rebar deformed part 40. Front and rear surfaces 42b,

The fixing head is provided with an upper and lower surface 43b which is maintained in the same cross-sectional shape from the end of the upper and lower surface 43a of the first molding portion 41a to the end 42 of the rebar deformation portion 40. Equipped rebar.
The method according to any one of claims 1 to 3,

The reinforcing bar portion 40 is disposed on the central axis with respect to the width (W) direction of the fixing plate 50,

The fixing plate 50 further includes a bolt hole 56 formed to be disposed on both sides with respect to the rebar deformable portion 40 to allow bolting through the bolt hole 56 when the reinforcing bar is connected. Reinforcing bars provided with a fixing head.
The method of claim 4, wherein

The bolt hole 56 is formed as a long hole having a long length on the central axis, the central axis is also inclined at a predetermined angle with respect to the vertical direction, even when the center axis of the reinforcing bars are inconsistent Reinforcing bar provided with a fixing head, characterized in that to facilitate.
In the manufacturing method of the rebar provided with a fixing head formed by connecting the fixing plate 50 to the end of the reinforcing bar 30,

By pressing the end of the reinforcing bar 30, the reinforcing bar 40 having a cross-sectional perimeter longer than the cross-sectional perimeter of the reinforcing bar 30 is integrated with the reinforcing bar 30 at the end of the reinforcing bar 30. Rebar deformation processing step to form a;

A fixing plate processing step of forming the fixing plate 50 as a flat plate so as to have an area larger than the cross-sectional area of the reinforcing bar deformation portion 40;

And a welding step of welding the end of the reinforcing bar deformed portion 40 to be fixed to the fixing plate 50.
The method of claim 6,

The fixing plate processing step further includes the step of forming the bolt holes 56 on both sides of the central axis with respect to the width (W) direction of the fixing plate 50,

The welding step is provided with a fixing head characterized in that the reinforcing bar 40 is arranged on the central axis with respect to the width (W) direction of the fixing plate 50 to be welded to the fixing plate 50. Method of manufacturing reinforced steel.