KR101223691B1 - Site Splicing Method of Pre-Assembled Rebar Columns - Google Patents

Abstract

In order to simplify the reinforcement concrete construction, a new construction method of bringing a pre-assembled reinforcement column 50 with a strip reinforcing bar around the column head in the factory and then assembling it with the beam and the lower reinforcement column was activated. However, various methods were attempted to connect the upper and lower reinforcement columns, but all unreasonable points were exposed. Therefore, a new method was needed that is different from the conventional method. It is also costly to connect each one of the column heads 10 with a coupler (FIG. 9) or gas pressure welding (FIG. 10), but the crane waiting time for hanging the upper reinforcing column during the jointing operation is too long. In addition, welding the column freckle inside the joint steel sheet (FIG. 7) may not only secure the thickness of the concrete 15 between the formwork and the joint steel sheet, but may also cause the concrete to fall off after pouring, and the construction lugs 30 may be Desorption is cumbersome disadvantage. As a method of solving this problem, the method of arranging the joint steel plate 20 inside the main bar was also applied (Fig. 8). However, when the thickness of the column bar is different, the sidewalls do not directly meet with the thin main bar and correct this. Additional work is needed.

When the thickness of the column head 10 is different as shown in Figs. 1 and 2, the present invention selectively adjusts the arrangement of the column heads to ensure the joints. In addition, the installation lug 30 is also easily installed, so as not to separate and remove after the joint operation. When the column head is concentrated around the corners of the column section as shown in Fig. 2 (a) by using this method, even greater flexural strength is secured even when the same amount of head bars are placed. And the work of cutting off the sharp corners of the pillar also has the advantage of becoming natural.

Description

Site Splicing Method of Pre-Assembled Rebar Columns}

In FIG. 1 (b), the strip reinforcing bar of the reinforced concrete column is designed to surround the column root. The strip reinforcing bars hold column pillars so that they do not deviate from the desired position during construction and after concrete curing. In addition, in the special case of receiving excessive axial force such that the length of the column is reduced (such as during earthquake load) it acts to restrain the column head 10 from going out of the section by the outward separation of the column concrete. However, at the reinforced concrete construction site, as shown in Fig. 3 (c), the column head is erected, and the band reinforcing bars 12 are wound around each other, and the method of assembling and assembling them with a binding line at each position where the column bars and the band bars meet meets work efficiency and construction. You must accept the lack of precision.

Reinforcing bars have a disadvantage in that rust (iron oxide) is generated when combined with oxygen in the air. Concrete cover to protect reinforcing steel bars to prevent rebar oxidation is specified in specification and regulations according to the durability of structure. Minimum coating thickness of column is 40mm. Therefore, the joints of the upper and lower reinforcement columns should have the same coating thickness as the column reinforcement, and there should be no risk factors such as the coating falling off.

When the column bar 10 and the band reinforcing bars 12 are assembled at the construction site using a binding line as shown in FIG. 3, since the reinforcing bars themselves do not exert any force, the temporary materials of the formwork and the strips surrounding the bars are concrete. It must withstand all the working loads of the pouring process. Therefore, the sound of the column freckle is not obliged to be welded or to couple machines using couplers. Most of them rely on overlapping joints. However, the overlapping joints should be secured to the upper and lower pillars to each other and bound with a binding line, so that the fixed length should be secured, and the joint lengths for the overlapping joints should be longer as the steel strength and diameter increase (Fig. 6). It is economically effective to use other jointing methods in place of these longer reinforcing bars. In addition, the column size is often increased in the design process to increase the cross section in order to secure the minimum spacing of the rebar due to the overlapping joint of the main bar.

In general, the thick columnar is connected to each floor of the building as shown in Fig. 4 (a) because it is dangerous to erect the column by the manpower and then to tie the band bars around the straps. However, the pre-assembled reinforcing column (Fig. 4 (b)) is secured by welding in the factory. It is possible to assemble two or three layers of column erect at one time.

The method of joining the column root to the coupler 38 as shown in FIG. 9 is expensive for screwing the reinforcing bar end and the coupler price, but the construction site becomes too long while the coupler is turned. FIG. 7 is an indirect bonding method in which a joint steel plate 20 is placed on a surface of a column column 10 and welded reinforcing bars and a joint steel plate inside a joint steel plate, and the joints of the upper and lower ends of the reinforcing columns are welded together at the construction site. In this way, the joint steel plate occupies a planar position that should surround the column-shaped steel bars, leaving only the plain concrete cover separated from the inner pillar concrete between the formwork and the smooth joint steel sheet. Therefore, when pouring concrete, it is difficult to properly fill the 40mm narrow gap, and there is a risk of cracking and falling off easily. In addition, there is a disadvantage that the detachable detachment of the temporary lug 30 to protrude to the outside of the joint steel sheet.

8 is a method of arranging the joint steel plate in the column root as a method to solve this. If the joint steel plate is installed inside the column head 10, welding of the column head and the joint steel plate in the corner is difficult (Figs. 8 and 9). In addition, even if the thickness of the column head is different even if the joint steel plate is changed to the p-shape as shown in Fig. 8 (c), the narrow column head is not directly encountered in the straight line (Fig. 8 (e)).

When using the method of pre-assembled by welding the column bar and the band reinforcing bars in the factory, the column heads of the line assembly reinforcement column 50 should be joined to each other. 3, 4 (a) is conventionally overlapping the reinforcement of the reinforcing bar is added to the amount of reinforcing bars, column poles should be arranged to shift each other by the thickness of the column in the plane. In order to overcome this difficulty, as shown in Fig. 7, the indirect joint method of welding the main end of the column joint position to the joint steel plate butt welding the upper and lower joint steel sheets but applied, but also found the problem of lack of concrete cover thickness and falling off It must be solved. In order to solve the above problems, as shown in Fig. 8, but the joint steel sheet is arranged inside the main bar, when the thickness of the column freckle is different from each other, the band steel is spaced apart by the difference between the thick bar and the thin bar as shown in Fig. 8 (d) 2 additional welding is required.

FIG. 11 shows a method of arranging horizontal joint steel plates at the upper and lower ends of column heads by another method, and welding the column heads directly to horizontal joint steel plates, and then welding the two horizontal joint steel plates at the site. However, even if the concrete pour hole 36 in the center of the horizontal joint steel sheet there is no guarantee that the concrete 15 is tightly filled in the lower horizontal joint steel sheet should be improved.

7 is also applied to the standard construction method for welding the bolt joints by welding the temporary lugs 30 vertically to the upper and lower reinforcement columns in the vertical direction, as in the case of ordinary steel column joints, even in the upper and lower reinforcement column joints However, temporary rugs need a method to reduce the trouble of removing after welding the upper and lower column joints. In addition, the jointed steel sheet is used as a means for joining the plant pre-assembled reinforcing column, but the unit cost is high compared to the weight of the reinforcing bar, so the amount of steel sheet should be minimized to secure economic feasibility.

1 and 2, the column joint steel plate 20 is arranged inside the column main column, and thus the steel sheet length is reduced compared to the case where the column base is used outside as shown in FIG. In addition, when the thickness of column pillars is not the same, the upper and lower lengths (widths) of the joint steel plates are different from each other according to the joint lengths of the column roots, and the left and right side ends protrude from the outer surface of vertically adjacent joint steel plates. A thick column pillar is welded and placed on a joint steel plate.

In a typical case of arranging the column head 10 in the corner of the column section, a thick column head is welded to the outside of the joint steel plate welded in a p-shape as shown in FIG. 1. The thickness of the concrete outside the joint steel plate becomes the normal coating thickness + column head + band reinforcing bar thickness, and it is easy to pour concrete and prevent the coating from falling off. In the case of enterprising to avoid placing the column head in the corner of the column as shown in Figure 2, the column head is welded to the outside of the joint steel plate welded with the K-shape, if the surface of the column head is unified with the same thickness of the column head to each joint steel plate There will be no gaps in the space. If the thickness of the column heads corresponding to each other corresponding to each other as described above, the size of the joint steel sheet can be designed differently according to the minimum weld seam length of the joint steel plate and the column head (see Figure 6 for the welding length of the column head and the joint steel plate) ). Temporary lugs are attached to the inner corner of the joint steel plate in the horizontal direction as shown in Figures 1 and 2 so that the up and down reinforcement columns to each other and the upper and lower temporary lugs can be bolted together.

Using this method, the following effects can be expected.

First, when the column head is welded to the outside of the joint steel plate, the coating thickness becomes thicker than the thickness of the column head, so that the workability is improved when concrete is poured and there is no fear of the coating falling off.

Second, the column joint steel plate can be placed inside the column root without having to unify the thickness of the column column.

If the thickness of the third column root is different, it is possible to minimize the amount of use of the joint steel sheet by unifying the thickness of the column root welded to each joint steel sheet (see Figs. 1, 2 and 6).

Fourth, it is possible to reduce the use of steel sheet than to arrange it outside by arranging the joint steel sheet inside the column root.

Fifth, the size and number of bolts for the temporary lugs attached to the joint plate are reduced and do not need to be removed after the column is joined.

Joint welding by welding the upper and lower part of the column is familiar to general steel structures. However, in order to joint the reinforced concrete column head 10 using the above method, the column head should be welded inside the joint steel plate 20 as shown in FIG. 7. This method, unlike the conventional method, is to place the joint steel sheet inside the column head, but the column joint steel sheet (20) in accordance with the general case (Fig. 1) and the case where it is not necessary (Fig. 2) to place the column head in the corner of the column section ) Make a different planar shape.

In the general case in which the column head is arranged in the corner of the column section, the column head is welded to the outside of the column joint steel plate welded in a p-shape as shown in FIG. That is, the column head 10 arranged at the corner is coupled to the outer surface end side of the two joint steel plate 20 'facing each other, the joint steel plate 20 "is coupled to the joint steel plate 20' to which the corner column head is coupled ) Is coupled to the inner side of the left and right side ends of the joint steel plate 20 'to which the corner pillars are coupled, so that the overall coupling form of the joint steel sheet is a' '' shape, where the column head thickness of each side of the square pillar Even if they are different from each other, placing the column heads of the same thickness in each joint steel plate maintains a straight line without shifting the column bars when welding the band bars.

In principle, the coarse one of the column roots should be arranged in the joint steel plate 20 'to which the column pillars of the corners are coupled. As shown in FIG. 5, a center column having almost no bending moments in the X and Y-axis directions may be arranged as shown in FIG. 5B, but a column having a large bending moment in one direction facing the outside of the building is shown in FIG. 5. It should be arranged as in (a). At this time, if the corresponding surface that should resist the large bending moment, that is, the joint steel plate 20 'to which the corner pillars are coupled, is arranged inside and outside the building plane, the rationality that the thick pillars are naturally arranged on the inner and outer surfaces of the pillar is induced. 1).

When the column roots do not have to be arranged in the corners of the column cross-sections, as shown in FIG. 2, the ends of adjacent joint steel plates 20 are brought into contact with each other so that the joining form of the joint steel plates becomes a 'ㅁ' shape as a whole. The column head is welded to the outer surface of the welded steel plate welded in ㅁ 'shape. At this time, if the thickness of the column heads are not the same, the column heads of the same thickness are arranged in each joint steel sheet. If there is no column freckle in the corner of the column cross section, it is also convenient to cut off the acute corner of the pillar corner to have a soft feeling (FIG. 2).

If the diameter of the column head is thick as shown in Figure 6, the welding field of the joint steel sheet should be long, so the height of the joint steel sheet should be increased. Therefore, when the thickness of the column root is different, the height of the joint steel plate 20 facing each other as shown in Figures 1 and 2, but the same, to differentiate the height between the adjacent joint steel plate 20 to improve the economics. Reinforcing columns are generally less rigid than steel columns such as H-beams, which is an advantage in field assembly work. If the column stiffness is too strong, care should be taken to adjust the verticality at the joint of the column, but since the reinforcing column is moderately wobbly, some vertical errors can be easily corrected by pushing and pulling. Therefore, assembling temporary rugs are arranged horizontally in the four corners of the column cross-section as shown in Fig. 1, 2, it is possible to make a temporary connection with only one bolt each.

In the case of jointing the reinforcing bar column pre-assembly through the above process, the steps for each step are as follows.

First, a plurality of pillars 10 are installed at each corner or each side of the square pillar. The number of column heads is calculated by the structural design, and the length can be from 1 floor to 3 floors, but it is manufactured within 3 floors in consideration of economy and constructability.

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Second, when the column head 10 is installed, the band reinforcement 12 is wound around the outside of the column head 10, and the column head 10 and the band reinforcement 10 are fixed by welding.

Third, each of the joint steel plate 20 is welded to the upper and lower ends of the column head 10 of each side of the square pillar, the joint steel plate is coupled to the inside of the column root. At this time, the column head is coupled to one joint steel plate is arranged to be the same diameter of the reinforcing bar to facilitate the welding between the band reinforcing bar 12 and the column head 10. The length of the joint steel plate 20 is different depending on the diameter and the number of the column head 10, and is determined according to the table "welding length of the reinforcing bars and steel plates" of FIG.

Fourth, the temporary lug 30 made of a plate is fixed to the joint steel plate 20 inside the corners where the adjacent joint steel plates 20 are coupled to each other. The temporary lug 30 cuts a plate and fixes it by welding to a joint steel plate, and a bolt hole is drilled in the center part of the plate to enable bolting.

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Fifth, in order to interconnect the plurality of pre-assembled reinforcement pillars having the joint steel plate 20 installed in the column head 10 up and down, the joint steel plate 20 and the temporary lug 30 is installed in the column head 10 The prefabricated reinforcing bar 50 'and the upper prefabricated reinforcing bar 50' are prepared, and the temporary lug 30 coupled to the upper joint steel plate 20 of the lower prefabricated bar 50 'and the upper part The temporary lug 30 coupled to the lower joint steel plate 20 of the prefabricated reinforcement column 50 "is mutually coupled with a bolt, thereby interconnecting the upper and lower prefabricated reinforcement columns.
Sixth, after the upper and lower prefabricated reinforcement column is temporarily bonded by the temporary lug 30, the upper joint steel plate 20 of the lower prefabricated reinforcement column 50 'and the lower joint of the upper prefabricated reinforcement column 50 ". The site where the steel plate meets is fixed by welding to integrate the upper and lower prefabricated reinforcement columns, and bolted using a temporary lug 30 at the corner of the joint steel plate 20 before fixing by welding, so that the upper and lower parts are welded. It is possible to ensure the safety of the pre-assembled reinforcement column.

This method is characterized in that through each of these steps, the top and bottom of the pre-fabricated reinforcement column manufactured by the factory in the field joint.

1 is a vertical joint method of the reinforcement column of the column column welded to the outside of the column-jointed steel plate welded in a p-shape,

Figure 2 is a vertical joint method of the reinforcing column of the column pillar welded to the outside of the column joint steel plate welded in ㅁ shape,

3 is a vertical joint method of the conventional column root,

Figure 4 (a) is the vertical joint method of the floor of the conventional column root,

Figure 4 (b) is a three-layer vertical joint method of the reinforcement column pre-assembled by welding in the factory,

5 is an explanatory diagram of the bending moment resistance capacity according to the arrangement method of the column root;

6 shows the length of the overlap joint and welded joint of the column freckle,

7 is a conventional vertical joint method of the reinforcement column welded column pillar inside the joint steel sheet,

8 is a feature comparison with the method of welding a joint steel sheet inside the column root;

9 is a method of connecting the column root with a coupler,

10 is a method of gas welding the column root joint,

FIG. 11 is a method of joining up and down reinforcing bar columns welded horizontally by welding a column joint steel plate to a column root end.

<Brief description of the symbols in the drawings>

10; Column root 12; Steel bars

15; Concrete 20; Joint plate

30; Hypothetical lug 32; Hypothetical Joint Bolt

34; Hypothetical joint steel sheet 36; Concrete pouring hole

38; Coupler

50; Prefabricated Rebar Column

Prefabricated rebar columns; Winding strips around the column bars to weld the points where the column bars and strip bars meet to secure rigidity (reinforced concrete columns are required only when the form is wrapped around and filled with concrete)

Column root; Coarse bars vertically installed in the reinforcing column

Column reinforcement; General term for columnar and band reinforcing bars constituting the reinforcing column

Coupler; Female threaded cylinder with screws on two rebar ends and screwed in between

Gas pressure welding; Rebar splice method that applies the gas flame high temperature to each other and compresses the ends of the reinforcing bars so that the rebar ends melt together.

Temporary lug; Temporary hardware that temporarily binds the upper and lower columns so as not to shake during the welding process (fixed with bolts and cut after welding the columns)

Flaky steel and two-stage welding; If the joints of different thicknesses are welded when the joint steel sheet is inside the main bar, the band reinforcing bars and the narrow column bars cannot meet in a straight line. Therefore, after welding the steel plate between the thin bar and the joint steel plate, How to re-weld different bars

Place column column at corner of column section; If the column needs to resist large bending moments in both X and Y directions, the flexural resistance strength increases if the column is placed in the corner of the column section even with the same amount of column root.

Corner sharpening; To make an octagonal cross section by attaching a triangular auxiliary formwork to the sharp part of the corner

Binding line; It is made of wrought iron, roasted, and used to bind rebar with several thin wires (20).

Cover thickness; Minimum thickness regulation to protect the reinforcement in reinforced concrete structure to ensure durability (generally based on 50 years of durability)

Minimum spacing between column roots; If the instantaneous spacing between column pillars is too narrow, concrete aggregate will not escape and adhesion strength will be reduced.

Panel zone; Structural major part where beams are joined in column

Claims (3)

In the field jointing method of the pre-fabricated reinforcing bar column 50 of the reinforced concrete square column, which is composed of a column main column 10, a strip reinforcing bar 12 and a joint steel sheet 20, (a) installing a plurality of column heads 10 on at least one of an edge or a face of the square pillar; (b) winding the strip reinforcing bar 12 outside the column main bar 10 and fixing the column main bar 10 and the strip reinforcing bar 10 by welding; (c) welding the joint steel plate 20 to each of the upper and lower ends of the column pillar 10 of each side of the square pillar by welding, the column roots are coupled to the opposite joint steel plate is the same in diameter and the joint steel sheet Coupled to the inner side of the column pillar; (d) fixing the temporary lug 30 made of a plate to the joint steel plate 20 inside the corners where the adjacent joint steel plates 20 are coupled to each other; (e) In order to interconnect the plurality of pre-assembled reinforcing bar columns 50 provided with the joint steel plate 20 and the temporary lug 30 to the column head 10, the joint steel plate 20 to the column head 10. And the lower prefabricated reinforcing bar column 50 'and the upper prefabricated reinforcing bar column 50' are installed on the upper joint steel plate 20 of the lower prefabricated bar column 50 '. Connecting the upper and lower prefabricated rebar columns by mutually coupling the temporary lugs 30 and the temporary lug 30 coupled to the lower joint steel plate 20 of the upper prefabricated reinforcement column 50 ″ with bolts; And (f) Upper and lower prefabricated reinforcing bar columns by welding a portion where the upper joint steel plate 20 of the lower prefabricated reinforcing bar column 50 'and the lower joint steel plate 20 of the upper prefabricated bar column 50' "meet by welding. Integrating a; The joint method of on-site reinforcement of the pre-assembled reinforcing column comprising a. In claim 1, The column head 10 disposed at the corner is coupled to the outer end of the two joint steel plate 20 'facing each other, and the joint steel plate 20 is vertically coupled to the joint steel plate 20' to which the corner pillar main head is coupled. ") Is coupled to the inner side of the left and right side ends of the joint steel plate 20 'to which the corner pillars are coupled, so that the joining form of the joint steel sheet is a' p 'shape, Field joining method of the pre-assembled reinforcing bar pillars, characterized in that the end of the adjacent joint steel sheet 20 to be in contact with each other so that the coupling form of the joint steel sheet is 'ㅁ' shape. In claim 1, Each joint steel plate 20 is calculated by calculating the required welding length according to the diameter of the column head 10 fixed to the joint steel plate 20, the site of the pre-assembled reinforcement column, characterized in that for determining the size of each joint steel plate Joint method.

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