Opening reinforcement method

Abstract

To provide an opening reinforcement method capable of strengthening the shear strength, bending strength, and axial strength of a steel beam having openings.SOLUTION: A square frame 21 having a rectangular frame shape is welded on the periphery of the open hole 15 on a first surface 12a of a web 12 of a steel beam 10. Further, on the periphery of the open hole 15 on a second surface 12b, which is the reverse surface of the first surface 12a, a square frame 22 having the same shape as the square frame 21 but rotated 45 degrees relative to the square frame 21 is welded. With this configuration, the area around an open hole 15 formed in a web 12 of a steel beam 10 is reinforced.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an opening reinforcement method for reinforcing a through hole formed in a web of a steel beam. [Background technology]

[0002] In steel beams such as H-shaped steel, a through hole may be formed in the web portion to allow piping or wiring to pass through. In this case, a reinforcing member is provided to suppress a decrease in the shear force of the beam (see, for example, Patent Documents 1 and 2). In the beam through hole reinforcing method described in Patent Document 1, the inclined surface of a ring-shaped reinforcing member is brought into contact with the inner surface of the through hole of the beam material, and the inclined surface of the ring-shaped reinforcing member temporarily fixed to the web portion of the beam material is welded to the inner peripheral surface of the through hole. In addition, the opening reinforcing member in Patent Document 2 includes a cylindrical portion fixed to the peripheral portion of the circular through hole, and a square frame portion having a plurality of sides in contact with the outer periphery of the cylindrical portion and integrated with the cylindrical portion via welding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-174311 A [Patent Document 2] JP 2022-115628 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the beam through hole reinforcing method of the above-mentioned Patent Document 1, the shear strength of the steel beam can be improved, but it is difficult to sufficiently reinforce the bending strength and axial strength of the steel beam. In addition, the opening reinforcing member of Patent Document 2 can reinforce the bending strength and axial strength of the steel beam, but the efficiency of the welding work is not good because the cylindrical part and the square frame part are welded. [Means for solving the problem]

[0005] An opening reinforcement method that solves the above-mentioned problems is a method of reinforcing the periphery of a through hole formed in a web of a steel beam by being joined to the periphery of the through hole, in which a first reinforcing member having a rectangular frame shape is welded to the peripheral portion of the through hole on a first surface of the web, and a second reinforcing member having a frame portion arranged differently from the frame portion of the first reinforcing member is welded to the peripheral portion of the through hole on a second surface that is the back side of the first surface. Effect of the Invention

[0006] According to the present invention, it is possible to reinforce the shear strength, bending strength and axial strength of a steel beam having an opening, and to improve workability. [Brief description of the drawings]

[0007] [Figure 1] 1 is a perspective view of a steel beam having an opening reinforced by an opening reinforcement method according to an embodiment of the present invention. [Diagram 2] 1 is a front view of a steel beam having an opening reinforced by an opening reinforcement method according to an embodiment of the present invention. [Diagram 3] 1 is a rear view of a steel beam having an opening reinforced by an opening reinforcement method according to an embodiment of the present invention. [Figure 4] 4 is a cross-sectional view taken along line 4-4 in FIG. 3. [Diagram 5] 13 is a front view of a steel beam having an opening reinforced by a modified example of an opening reinforcement method. FIG. [Figure 6] 13 is a side cross-sectional view of a steel beam having an opening reinforced by a modified example of an opening reinforcement method. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of a method for reinforcing an opening will be described below with reference to Figures 1 to 4. Figures 1 to 4 are a perspective view, a front view, a back view, and a side cross-sectional view of a steel beam for reinforcing an opening. As shown in Fig. 1, a steel beam 10 is composed of an H-shaped steel having upper and lower flanges 11 and a web 12 connecting them. A circular through hole 15 is formed in this web 12 to allow piping and wiring to pass through. The through hole 15 is reinforced by an opening reinforcing member 20.

[0009] As shown in Figs. 2 and 3, the opening reinforcement member 20 includes rectangular frame portions 21 and 22 having a substantially square rectangular frame shape (rectangular frame shape). The rectangular frame portions 21 and 22 are formed by cutting a rectangular steel pipe into rings of a predetermined thickness and have the same shape. The rectangular frame portions 21 and 22 are arranged to surround the through hole 15. Specifically, the rectangular frame portions 21 and 22 are welded to the first surface 12a of the web 12 and the second surface 12b on the back side of the first surface 12a by welds W1 and W2 provided on the outer periphery. The rectangular frame portion 21 of this embodiment is arranged so that a pair of opposing side portions 21a are parallel to the extension direction of the flange portion 11 (steel beam 10). Furthermore, when the rectangular frame portions 21, 22 are projected onto the parallel plane of the web 12, the side portion 21a of the rectangular frame portion 21 and the side portion 22a of the rectangular frame portion 22 form an angle of 45 degrees. In this case, the rectangular frame portion 22 is disposed so as to be rotated 45 degrees with respect to the rectangular frame portion 21, centered on the central axis C1 of the circle of the through hole 15. Note that the rotation angle of this rectangular frame portion 22 does not have to be strictly 45 degrees, but may be any angle that allows shear reinforcement and is substantially recognized as 45 degrees.

[0010] Then, the opening reinforcing member 20 is disposed around the through hole 15 and welded. Specifically, the opening reinforcing member 20 is welded so that the welds W1, W2 on the outer periphery of the rectangular frame portions 21, 22 are positioned on the periphery of the through hole 15. In this case, the shortest distance from the through hole 15 to the rectangular frame portions 21, 22 is the same.

[0011] (action) In this embodiment, a rectangular frame portion 21 and a rectangular frame portion 22 rotated 45 degrees relative to the rectangular frame portion 21 are welded to the periphery of the through hole 15 on the first surface 12a and the second surface 12b of the steel beam 10. As a result, the side portion 22a of the rectangular frame portion 22 is disposed at 45 degrees relative to the side portion 21a of the rectangular frame portion 21 around the through hole 15, thereby providing shear reinforcement.

[0012] According to this embodiment, the following effects can be obtained. (1) The opening reinforcement member 20 of this embodiment includes rectangular frame portions 21 and 22. On the first surface 12a and the second surface 12b of the steel beam 10, the rectangular frame portion 21 and the rectangular frame portion 22 rotated 45 degrees relative to the rectangular frame portion 21 are welded to the periphery of the through hole 15. This allows shear reinforcement to be performed around the through hole 15 in the extension direction of the steel beam 10 and in a direction at 45 degrees thereto, thereby providing a shear reinforcement effect equal to or greater than that of a circular ring.

[0013] (2) In this embodiment, the rectangular frame parts 21 and 22 have the same shape and are formed by cutting a rectangular steel pipe into rings of a predetermined thickness. This allows the opening to be reinforced simply by welding the outer periphery of the rectangular frame parts 21 and 22 at the weld parts W1 and W2, improving workability.

[0014] (3) In this embodiment, the rectangular frame portions 21 and 22 of the opening reinforcing member 20 have a rounded rectangular shape. This makes it possible to suppress stress concentration at the corners of the rectangular frame portions 21 and 22. This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0015] In the above embodiment, the rectangular frame portions 21, 22 having the same shape are provided as the first and second reinforcing members on the first surface 12a and the second surface 12b of the web 12 of the steel beam 10. Instead of one of the rectangular frame portions 22 (21), a member having a cylindrical shape may be disposed.

[0016] For example, the steel beam 30 shown in FIG. 5 and FIG. 6 is provided with an opening reinforcement member 40. The opening reinforcement member 40 has a rectangular frame portion 41 having a substantially square rectangular frame shape, and a cylindrical portion 42. The rectangular frame portion 41 is welded at a welded portion W5 at the periphery of the through hole 35 on the first surface 32a of the web 32 of the steel beam 30. The rectangular frame portion 41 is disposed so that a pair of opposing sides are parallel to the extending direction of the flange portion 31 of the steel beam 30, similar to the rectangular frame portion 21. The cylindrical portion 42 has a circular ring shape larger than the circular through hole 35 formed in the web 32. The cylindrical portion 42 is welded at a welded portion W6 at the outer periphery of the through hole 35 on the second surface, which is the back surface of the first surface 32a, so that the center of the cylindrical portion 42 is the center of the through hole 35. This cylindrical portion 42 has the same thickness as the rectangular frame portion 41, and has a size such that the outer periphery of the cylindrical portion 42 is the same as the outer periphery of the rectangular frame portion 41. It is preferable that this cylindrical portion 42 has a size within the range from a size inscribed in the rectangular frame portion 41 to a size circumscribed circumferentially around the rectangular frame portion 41.

[0017] In the above embodiment, the outer peripheral edges of the rectangular frame portions 21, 22 of the opening reinforcement member 20 in the web 12 of the steel beam 10 are welded at the welds W5, W6. The welding positions and welding method of the first reinforcement member and the second reinforcement member are not limited to this. The inner peripheral edges of the rectangular frame portions 21, 22 may be welded, or they may be welded at a plurality of spaced apart welds.

[0018] In the above embodiment, the rectangular frame portions 21, 22 of the opening reinforcing member 20 have the same thickness. The rectangular frame portions 21, 22 do not have to have the same thickness. Next, the technical ideas that can be understood from the above embodiment and other examples will be described below. (a) The method for reinforcing an opening according to any one of claims 1 to 3, characterized in that outer peripheral edges of the first reinforcing member and the second reinforcing member are welded to the web.

[0019] (b) The method for reinforcing an opening according to any one of claims 1 to 3 or (a), characterized in that at least one of the first reinforcing member and the second reinforcing member has a square frame shape and is arranged so that the extension direction of a pair of opposing sides of the square is parallel to the extension direction of the steel beam. [Explanation of symbols]

[0020] C1...central axis, W1, W2, W5, W6...welded portions, 10, 30...steel beams, 11, 31...flange portions, 12, 32...webs, 12a, 32a...first surfaces, 12b...second surfaces, 15, 35...through holes, 20, 40...opening reinforcement members, 21, 41...rectangular frame portions as first reinforcement members, 21a, 22a...side portions, 22...rectangular frame portions as second reinforcement members, 42...cylindrical portions as second reinforcement members.

Claims

1. A method for reinforcing an opening by joining a through hole formed in a web of a steel beam to reinforce the periphery of the through hole, a first reinforcing member having a rectangular frame shape is welded to a peripheral portion of the through hole on the first surface of the web; An opening reinforcement method characterized by welding a second reinforcing member having a frame portion arranged differently from the frame portion of the first reinforcing member to the peripheral portion of the through hole on a second surface that is the back side of the first surface.

2. The through hole has a circular shape, The opening reinforcing method described in claim 1, characterized in that the second reinforcing member has the same shape as the first reinforcing member and is positioned rotated 45 degrees relative to the first reinforcing member around the circular central axis of the through hole.

3. The opening reinforcement method according to claim 1, characterized in that the second reinforcing member has a cylindrical shape having a size between a size inscribed in the first reinforcing member and a size circumscribed around the first reinforcing member.

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