Reinforcing plate and reinforcing plate joint structure

Abstract

To appropriately execute welding even when a steel pipe inner diameter at a place where a reinforcement is disposed is smaller than the width of the reinforcement plate.SOLUTION: A plate-like reinforcement plate inserted into a rectangular steel pipe having a square sectional shape and having four sides welded at outer peripheral ends to the inner surface of the rectangular steel pipe is configured such that at least a pair of two sides of the four sides of the reinforcement plate opposite to each other is provided with a bevel having an opening on one plate surface side, and at the bevel disposed on the opposite side of the pair of two sides, openings are provided on the plate surface sides of the opposite sides.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to a reinforcing plate and a reinforcing plate joining structure.

Background Art

[0002] In a steel frame building, in order to transmit the bending moment received from a beam to a column, a reinforcing plate called an inner diaphragm, which is one to two ranks thicker than the plate thickness of the beam flange, is often provided in the column-beam joint structure. In particular, when the beam eccentricities of a plurality of beams 4 and 5 joined to a steel pipe column 1 are different, as shown in FIG. 1, a reinforcing plate called a through diaphragm 6 is joined to the arrangement height of the beam flange 4a of the beam 4 with a large beam eccentricity, and an inner diaphragm 2 may be joined to the inside of the steel pipe column 1 at the arrangement height of one beam flange 5a of the beam 5 with a small beam eccentricity. At this time, the two through diaphragms 6 are joined to both ends of a short steel pipe (sometimes called a "dice"). The inner diaphragm 2 is disposed inside the dice 3.

[0003] Patent Document 1 discloses a stepped column-beam joint structure having a through diaphragm and an inner diaphragm, in which an inner diaphragm welded inside a steel pipe is provided so as to be shifted from the position of a beam flange with a low beam eccentricity joined to the column-beam joint structure. According to this, it is possible to widely secure the distance between the backing metal of the welding portion of the through diaphragm and the backing metal of the welding portion of the inner diaphragm, and it is possible to prevent interference between the backing metals.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a structure having such an inner diaphragm 2, as shown in FIG. 2, after the inner diaphragm 2 is disposed inside the die 3, the outer peripheral portion of the inner diaphragm 2 and the inner surface of the die 3 are welded and joined. In order to dispose the inner diaphragm 2 inside the die 3, it is necessary to process the outer peripheral shape of the inner diaphragm 2 to be smaller than the inner peripheral shape of the die 3. When welding the die 3 and the inner diaphragm 2 by a complete penetration groove weld with a J-groove, generally a gap (root gap) of about 7 mm to 9 mm is provided between the end face of the inner diaphragm 3 and the inner surface of the die. Therefore, as shown in FIG. 3, when the inner diameter of the opening of the die 3 is d (mm), the width of the inner diaphragm 2 is processed to be about d - 18 (mm) or more and d - 14 (mm) or less.

[0006] Here, cold-formed square steel pipes are often used for the die 3. However, not limited to cold forming, the square steel pipe is not completely straight in the axial direction of the steel pipe, and as shown in FIG. 4, there may be a dent on the inner side of the steel pipe cross-section. According to the literature (Japan Building Center, Cold-Formed Square Steel Pipe Design and Construction Manual, 1st Edition, 2018.2), the dent on the flat part of the square steel pipe is controlled to be 0.5% or less of the steel pipe diameter (mm) and 3.0 mm or less. That is, the inner diameter d (mm) of the die 3 at the mounting height position of the inner diaphragm 2 may be up to 6 mm smaller than the inner diameter of the opening of the die 3. Even in this case, as described above, since the width of the inner diaphragm 2 is processed to be about 14 mm to 18 mm smaller than the inner diameter of the opening of the die 3, even if the inside of the die 3 is most dented within the specified range, the inner diaphragm 2 can be horizontally disposed inside the die 3. Therefore, when joining the inner diaphragm 2 to the inside of the die 3 by complete penetration welding, it is relatively easy to dispose the inner diaphragm 2 inside the die 3.

[0007] On the one hand, full penetration welding requires a backing bar, which may be time-consuming in construction. When welding the inner diaphragm inside the square steel pipe, it may be desired to join the inner diaphragm by partial penetration welding or full penetration welding with a K-shaped groove. In this case, unlike the full penetration welding with the L-shaped groove described above, there is an advantage that a backing bar is not required, but it is necessary to control the gap (= root gap) between the inner diaphragm and the inner surface of the die to be 3 mm or less (Japan Society of Civil Engineers: Standard Specifications for Building Works JASS6 Steel Structure Works 11th Edition, 2018.1).

[0008] Then, assuming that the inner diameter of the opening of the die 3 is d (mm), the width of the inner diaphragm 2 needs to be processed to be approximately d - 6 (mm) or more and d (mm) or less. Here, as described above, the inner surface of the die 3 is not completely straight in the axial direction of the steel pipe, and the inner diameter of the die 3 at the mounting height position of the inner diaphragm 2 may be up to 6 mm smaller than the inner diameter of the opening. This means that the inner diameter of the die 3 may be smaller than the width of the inner diaphragm 2. In such a case, the inner diaphragm 2 will get caught inside the die 3 and tilt greatly. At this time, it is necessary to take out the inner diaphragm 2 from the die 3 once, adjust the width of the inner diaphragm 2, and then put it inside the die 3 again. Therefore, when joining the inner diaphragm 2 by partial penetration welding or full penetration welding with a K-shaped groove, there is a problem that it is very difficult to place the inner diaphragm inside the die.

[0009] Therefore, an object of the present disclosure is to provide a reinforcing plate that can be appropriately welded even when the inner diameter of the steel pipe is smaller than the width of the reinforcing plate at the portion where the reinforcing plate is disposed. Further, a structure using this reinforcing plate is provided.

Means for Solving the Problems

[0010] The present application discloses a plate-shaped reinforcing plate having four sides that is inserted into a square-section square steel pipe and whose outer peripheral end is welded to the inner surface of the square steel pipe. At least one pair of two opposite sides among the four sides of the reinforcing plate are provided with V-shaped grooves having openings on one of the plate surfaces, and in the V-shaped grooves arranged on the opposite sides of the pair of two sides, the openings are provided on the plate surfaces on the opposite sides of each other.

[0011] The present application also discloses a reinforcing plate joining structure including a square steel pipe having a square cross-sectional shape, the above-described reinforcing plate disposed inside the square steel pipe, and a welded portion provided in the V-shaped groove so as to join the inner surface of the square steel pipe and the reinforcing plate.

[0012] The present application also discloses a plate-shaped reinforcing plate having four sides that is inserted into a square-section square steel pipe and whose outer peripheral end is welded to the inner surface of the square steel pipe. At least one pair of two opposite sides among the four sides of the reinforcing plate are provided with K-shaped grooves having openings on both plate surfaces, and the width of one opening is larger than the width of the other opening. In the K-shaped grooves arranged on the opposite sides of the pair of two sides, the openings with the larger width are provided on the plate surfaces on the opposite sides of each other.

[0013] The present application also discloses a reinforcing plate joining structure including a square steel pipe having a square cross-sectional shape, the above-described reinforcing plate disposed inside the square steel pipe, and a welded portion provided in the K-shaped groove so as to join the inner surface of the square steel pipe and the reinforcing plate.

Advantages of the Invention

[0014] According to the present disclosure, even when the inner diameter of the steel pipe is smaller than the width of the reinforcing plate at the portion where the reinforcing plate is disposed, appropriate welding can be performed.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

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Figure 16

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Figure 19

Embodiments for Carrying Out the Invention

[0016] 1. Reinforcing plate structure 1.1. Partial penetration welding Figs. 5 and 6 are perspective views schematically showing the appearance of the reinforcing plate joining structure 10 according to one embodiment. Fig. 6 is a cross-sectional view in the direction along the pipe axis of the die 11 of the reinforcing plate joining structure 10.

[0017] As can be seen from Figs. 5 and 6, the reinforcing plate joining structure 10 is composed of a die 11 which is a square steel pipe and an inner diaphragm 12 which is a reinforcing plate. In this embodiment, the reinforcing plate joining structure 10 has a partial penetration weld portion 13. That is, in the reinforcing plate joining structure 10, the inner diaphragm 12 which is a reinforcing plate is arranged inside the die 11, and the inner surface of the die 11 and the outer peripheral end portion of the inner diaphragm 12 are joined by partial penetration welding. The fact that it is partial penetration welding can be recognized by the absence of a backing plate.

[0018] 1.1.1. Die The die 11 is one aspect of a square steel pipe having a square cross-sectional shape and is as known. Including the die 11, the square steel pipe of this embodiment is allowed to have a recess on the inside so that its inner diameter becomes smaller as described with reference to Fig. 4 above. However, the allowable range is 0.5% or less of the steel pipe diameter (mm) and 3.0 mm or less as described above.

[0019] 1.1.2. Inner diaphragm The inner diaphragm 12 is a plate-like member having four sides that functions as a reinforcing plate arranged inside the die 11, and includes two plate surfaces (surfaces orthogonal to the plate thickness direction) 12a that constitute the front and back. Figs. 7 and 8 show diagrams for explanation. Fig. 7 is a plan view of the inner diaphragm 12, and Fig. 8 is a cross-sectional view taken along line A-A of Fig. 7. As can be seen from Fig. 7, notches 12b are provided at its four corners in plan view. This eliminates the problem of the arrangement of the inner diaphragm 12 due to interference with the inner corner portion on the inner surface of the die 11.

[0020] In addition, since the inner diaphragm 12 is joined to the inside of the die 11 by partial penetration welding as described above, it has a groove 12c for partial penetration welding on its four sides. Fig. 9 shows an enlarged view focusing on the part of the groove 12c. As can be seen from Fig. 9, in this embodiment, it has a V-shaped groove. That is, the groove 12c is provided only on one plate surface 12a side of the inner diaphragm 12, and an opening 12d is provided on one plate surface 12a side. The form of the groove is not particularly limited, and the groove angle is as known. The length f of the root face is not limited either, and the length f of the root face may be 0 (mm).

[0021] In the inner diaphragm 12 of this embodiment, the grooves 12c provided on the opposite sides among the four sides are configured such that the plate surface 12a on which the opening 12d is arranged is opposite. Thereby, even when the inner diameter of the die 11 is smaller than the width of the inner diaphragm 12 at the part where the inner diaphragm 12 is arranged, appropriate welding can be performed. The reason will be explained later.

[0022] 1.2. Full penetration welding The inner diaphragm of the present disclosure can also be used for grooves that do not require a backing bar in full penetration welding. Fig. 10 shows a diagram for explanation. Fig. 10 is a view from the same perspective as Fig. 9 and is a diagram for explaining the form of the inner diaphragm 20 that functions as a reinforcing plate. Since the inner diaphragm 20 can be considered in the same way as the inner diaphragm 12 except for the shape of the groove, the shape of the groove will be explained here.

[0023] As can be seen from Fig. 10, this embodiment has a K-shaped groove. That is, it has a groove 20a on one plate surface 12a side and a groove 20b on the other plate surface 12a side. In this embodiment, the groove 20a has an opening 20ab on the plate surface 12a side, the groove 20b has an opening 20bb on the plate surface 12a side, and the width L1 of the opening 20ab is configured to be larger than the width L2 of the opening 20bb. The opening angle and the length of the root surface are not particularly limited and can be set to an appropriate size as needed. The length f of the root surface may be 0 (mm).

[0024] In the inner diaphragm 20 of this embodiment, among the four sides, the plate surfaces 12a where the openings 20ab are arranged are opposite to each other for the openings provided on the opposite sides, and the plate surfaces 12a where the openings 20bb are arranged are opposite to each other. Thus, even when the inner diameter of the die 11 at the portion where the inner diaphragm 20 is arranged is smaller than the width of the inner diaphragm 20, it can be appropriately welded. The reason will be explained later.

[0025] 2. Effects, etc. As shown in FIG. 11, for a die with a reduced inner diameter at the position where the inner diaphragm is arranged, if an inner diaphragm having a conventional opening shape and a width larger than the inner diameter of the narrowed die is to be arranged, it will be in an inclined posture with an angle of θ. Even in such an inclined posture, if the inclination θ is very small, it is considered not to have a problem in construction. For example, in the literature (Architectural Institute of Japan, Standard Specifications for Building Construction JASS6 Steel Structure Work, 11th Edition, 2018.1), in the case of a welded joint with an L-shaped opening, the allowable management angle is 2.5° (the limit allowable angle is 5°). That is, at the position where the inner diaphragm is arranged, even when the inner diameter of the die is smaller than the width of the inner diaphragm and is inclined as shown in FIG. 11, if the inclination is within the angle allowable in construction management, the inner diaphragm can be welded directly. However, this angle is preferably as small as possible.

[0026] As shown in FIG. 11, when the openings on both sides are provided on one surface side of the inner diaphragm, θ will inevitably become large. On the one hand, as shown in FIG. 12, according to the inner diaphragm 12 described above, in the two openings 12c arranged on the opposite side, since the opening 12d is provided on the plate surface 12a on the opposite side, even for inner diaphragms having the same width, when the inner diaphragm 12 contacts the inner surface of the die 11 inside the die 11, the inclination θ of the inner diaphragm 12 can be made smaller than before.

[0027] Therefore, at the part where the inner diaphragm 12 (reinforcing plate) is arranged, even when the inner diameter of the die 11 (square steel pipe) is smaller than the width of the inner diaphragm 12, it becomes possible to increase the scenes where appropriate welding can be performed. The same applies to the inner diaphragm 20. In addition, since it becomes easier to arrange the inner diaphragm 12 inside the die 11, it becomes easier to apply welding methods that do not require backing bars, such as partial penetration welding and complete penetration welding of K-shaped grooves, to the joining of the inner diaphragm.

Example

[0028] 3. Example To show the benefits of the inner diaphragm (reinforcing plate) of the present disclosure, a comparative study by numerical calculation was conducted on inner diaphragms having three cross-sectional shapes shown in FIGS. 13 to 15. Comparative example 1 shown in FIG. 13 is an example of an inner diaphragm without a groove, and comparative example 2 shown in FIG. 14 is a conventional L-shaped groove and is an inner diaphragm having an opening on the same plate surface side. And the example shown in FIG. 15 is an inner diaphragm modeled after the example of the inner diaphragm 12 when having the L-shaped groove shown in FIG. Here, as shown in FIGS. 13 to 15, let the width of the inner diaphragm be B d (mm), the plate thickness of the inner diaphragm be t d (mm), the inner diameter of the die be D (mm), the groove angle of the inner diaphragm be α (°), the size of the root surface of the groove of the inner diaphragm be f (mm), the inclination of the inner diaphragm be θ (°) (however, θ ≤ α), and the gap between the inner surface of the die and the inner diaphragm be x (mm). Then, the gap x in each example can be geometrically obtained, and comparative example 1 is obtained from formula (1), comparative example 2 is obtained from formula (2), and example 1 is obtained from formula (3). x = D - B d ·cosθ - t d ·sinθ …(1) x = D - B d ·cosθ - f·sinθ …(2) x = D - B d ·cosθ + (t d - 2·f)·sinθ …(3)

[0029] Assume the case where the inner diameter D of the die is smaller than the width B of the inner diaphragm, and set D = B d - 1 (mm). Then, from equations (1) to (3), the gap x in each case is represented by equations (4) to (6) respectively. d - 1 (mm). Then, from equations (1) to (3), the gap x in each case is represented by equations (4) to (6) respectively. x = B d ·(1 - cosθ) - t d ·sinθ - 1 …(4) x = B d ·(1 - cosθ) - f·sinθ - 1 …(5) x = B d ·(1 - cosθ) + (t d - 2·f)·sinθ - 1 …(6)

[0030] Using the above - shown equations (4) to (6), numerical calculations were performed for the four cases shown in Table 1.

[0031]

Table 1

[0032] The results showing the relationship between x and θ are shown in FIGS. 16 to 19. FIG. 16 is for Case 1, FIG. 17 is for Case 2, FIG. 18 is for Case 3, and FIG. 19 is for Case 4. Note that the size f of the root surface in each case was set to 2 mm. In FIGS. 16 to 19, the horizontal axis represents the inclination θ of the inner diaphragm, and the vertical axis represents the gap x between the inner diaphragm and the die. When the gap x is 0 or less, it means they are in contact. Also, the 〇 marks shown in each figure represent the inclination θ of the inner diaphragm when the gap x becomes 0 in each example, and the black broken line represents the management allowable angle (2.5°) shown in the above literature. That is, in each graph, if the 〇 mark is located to the left of this broken line, it means that the construction conditions of the inner diaphragm are satisfied. As can be seen from FIGS. 16 to 19, it can be seen that only Example 1 satisfies the conditions in all cases.

Explanation of Signs

[0033] 10 Reinforcing plate joint structure 11 Square steel pipe column (die) 12, 20 Reinforcing plate (inner diaphragm) 13 Welded part

Claims

1. A plate-shaped reinforcing plate inserted into a square-section square steel pipe and having four sides whose outer peripheral ends are welded to the inner surface of the square steel pipe, wherein at least one pair of opposite sides among the four sides of the reinforcing plate are provided with V-shaped grooves having openings on one of the plate surfaces, and in the V-shaped grooves arranged on the opposite sides of the pair of sides, the openings are provided on the plate surfaces on the opposite sides of each other. Reinforcing plate.

2. A square steel pipe having a square cross-sectional shape, the reinforcing plate according to Claim 1 disposed inside the square steel pipe, and a welded portion provided in the V-shaped groove so as to join the inner surface of the square steel pipe and the reinforcing plate. Reinforcing plate joining structure.

3. A plate-shaped reinforcing plate inserted into a square-section square steel pipe and having four sides whose outer peripheral ends are welded to the inner surface of the square steel pipe, wherein at least one pair of opposite sides among the four sides of the reinforcing plate are provided with K-shaped grooves having openings on both plate surfaces, and the width of one of the openings is larger than the width of the other opening, and in the K-shaped grooves arranged on the opposite sides of the pair of sides, the openings with the larger width are provided on the plate surfaces on the opposite sides of each other. Reinforcing plate.

4. A square steel pipe having a square cross-sectional shape, the reinforcing plate according to Claim 3 disposed inside the square steel pipe, and a welded portion provided in the K-shaped groove so as to join the inner surface of the square steel pipe and the reinforcing plate. Reinforcing plate joining structure.

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