Steel beam and steel column connection structure with braces

Abstract

To provide a joint structure for steel beams and steel columns and braces that can prevent interference between the brace end connection plate and the panel core, thereby allowing the application of conventional evaluation formulas to the load-bearing capacity and rigidity of the steel plates forming the panel core. [Solution] The steel beam and steel column and brace joining structure 100 is such that the upper column 30A and lower column 30B, which are steel columns 30, are welded to the upper end 12 and lower end 13 of the non-diaphragm type panel core 10, the steel beam 40 is welded to the panel core 10, and the end 52 of the brace 50 is joined to the end 52 of the steel beam 50 by a steel joining plate 60 which is welded to the steel beam 30 and the steel beam 40. The joining plate 60 has a first end face 62 which is welded to the steel beam 40 and a second end face 64 which is welded to the steel column 30, and a scallop 66 is provided between the first end face 62 and the second end face 64 to prevent interference with the panel core 10.

Description

Technical Field

[0001] The present invention relates to a joint structure of a steel beam, a steel column and braces.

Background Art

[0002] In a column-beam joint part in a steel structure building where a square steel pipe is applied as a steel column and an H-shaped steel is applied as a steel beam, a through diaphragm type, an inner diaphragm type, etc. are adopted. The column-beam joint structure of the through diaphragm type has a structure in which a through diaphragm is welded and fixed so as to project outward from the panel core made of a square steel pipe at positions corresponding to the upper and lower flanges of the steel beam. The flange of the steel beam made of H-shaped steel is welded to the through diaphragm projecting outward, and the upper and lower square steel pipe columns are welded to the upper and lower through diaphragms. Further, when the beam deflections of the left and right steel beams are different, in addition to the upper and lower through diaphragms, an inner diaphragm is welded at a position corresponding to the flange of the steel beam with a lower beam deflection, for example, inside the panel core.

[0003] However, in these column-beam joint structures of the through diaphragm type and the inner diaphragm type, the manufacturing man-hours tend to increase during manufacturing, and further, the welding length also tends to become long. Therefore, generally, the manufacturing becomes complicated, it takes time for manufacturing, and there is a problem that the manufacturing cost tends to be high.

[0004] Therefore, Patent Document 1 proposes a column-beam joint structure for joining the columns and beams of a building in a so-called non-diaphragm type, which omits the diaphragm. The column-beam joint structure described in Patent Document 1 (here, column-beam joint structure) is a column-beam joint structure in which a square steel pipe column and a steel beam are joined to a non-diaphragm type steel panel core. The steel panel core consists of four steel plates joined to each other via welds, with a rectangular cross-sectional shape perpendicular to the extension direction, the thickness of the steel plates being greater than the thickness of the square steel pipe column, the core depth of the steel panel core being greater than the beam depth of the steel beam, and there being an excess length between the upper and / or lower end of the steel panel core and the upper and / or lower end of the steel beam, with the excess length lp of the excess length having a length that satisfies a conditional equation based on yield line theory. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 7009141 [Overview of the project] [Problems that the invention aims to solve]

[0006] According to the column-beam joint structure described in Patent Document 1, the excess length lp of the excess length portion is set to satisfy the conditional equation based on yield line theory, thereby enabling a rigid joint between the steel panel core and the steel beam, even when a non-diaphragm type is applied to the steel panel core.

[0007] Incidentally, in the column-beam joint structure described in Patent Document 1, when the brace is pulled (attached) to the panel zone side, there is a possibility that the connecting plate, such as a gusset plate, attached to the end of the brace may interfere with the panel core. In this case, when the connecting plate at the end of the brace interferes with the panel core, the mode (mechanism) of out-of-plane bending deformation of the steel plate forming the panel core will differ from the mode when there is no interference, and conventional evaluation formulas for evaluating the strength and rigidity of the steel plate cannot be applied, making it necessary to create a new evaluation formula. Here, as a conventional evaluation formula for evaluating the strength and rigidity of the steel plate, we can cite the formula for the beam end moment jMp at the full plastic strength of the column-beam joint in 4.2.5 "Non-diaphragm type hollow section column-beam joint" of the Steel Structure Joint Design Guidelines 2021 Revised by the Architectural Institute of Japan.

[0008] The present invention has been made in view of the above problems, and relates to a joint structure between steel beams and steel columns and braces, in which steel columns and steel beams are welded to a panel core, and the joint plates at the ends of braces are welded to the steel beams and steel columns, and aims to provide a joint structure between steel beams and steel columns and braces that can prevent interference between the joint plates at the ends of the braces and the panel core, thereby allowing conventional evaluation formulas to be applied to the load-bearing capacity and rigidity of the steel plates forming the panel core. [Means for solving the problem]

[0009] To achieve the above objective, one embodiment of the joint structure between steel beams and steel columns and braces according to the present invention is: A non-diaphragm type panel core consisting of a four-sided box or square steel pipe formed by welding together four steel plates, to which upper and lower steel columns are welded, to which steel beams are welded, to which steel beams are welded, and to which steel connecting plates to which the ends of braces are welded, to which steel beams are welded, to which steel connecting plates to which the ends of braces are welded, in a steel beam and steel column and brace connection structure, The aforementioned bonding plate is It comprises a first end face that is welded to the steel beam and a second end face that is welded to the steel column, A scallop is provided between the first end face and the second end face to prevent interference with the panel core.

[0010] According to this embodiment, the steel beam and steel column and brace joint structure is characterized in that a steel column is welded to a non-diaphragm type panel core made of a four-sided box or square steel pipe, a steel beam is welded to the panel core, and a steel joint plate to which the ends of the brace are welded is to the steel column and steel beam. The joint plate has a first end face to which it is welded to the steel beam and a second end face to which it is welded to the steel column, and a scallop is provided between the first and second end faces to prevent interference with the panel core, thereby preventing interference between the joint plate at the end of the brace and the panel core. As a result, conventional evaluation formulas can be applied to the load-bearing capacity and rigidity of the steel plate forming the panel core.

[0011] Furthermore, in another embodiment of the steel beam and steel column and brace connection structure according to the present invention, The welding joint between the first end face and the steel beam, and the welding joint between the second end face and the steel column, are characterized by being double-sided fillet welding or double-sided partial penetration welding.

[0012] According to this embodiment, the welding joint between the first and second end faces of the joining plate and the steel beams and steel columns is performed by double-sided fillet welding or double-sided partial penetration welding, thereby enabling a high-strength joint between the joining plate and the steel beams and steel columns under good joint properties.

[0013] Furthermore, in another embodiment of the steel beam and steel column and brace connection structure according to the present invention, The yield axial force of the brace, Ny, is characterized by satisfying the following equation (X).

[0014]

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[0015] According to this aspect, by defining the yield axial force Ny of the brace by Equation (X) and setting the axial force limit in design for the brace, the influence of the axial force of the brace on the steel plate of the panel core can be reduced.

[0016] More specifically, due to the bending at the end of the steel beam during an earthquake, the steel plate of the panel core may deform, but the deformation of the steel plate can be alleviated by the vertical component by the brace. However, when the axial force of the brace becomes unexpectedly large, the deformation mode of the steel plate goes beyond being alleviated and becomes an unexpected deformation mode, and based on this, the conventional general strength formulas and evaluation formulas cannot be applied.

[0017] Therefore, an axial force limit (upper limit) is provided for the brace by Equation (X), and on the premise that an axial force below this upper limit acts from the brace, the steel plate of the panel core is assumed to be in a deformation mode within the expected range, and the conventional general strength formulas and evaluation formulas can be applied.

[0018] In addition, another aspect of the joint structure of the steel beam, steel column, and brace according to the present invention is characterized in that the welding length lx between the first end face and the steel beam and the welding length ly between the second end face and the steel column satisfy the following Equation (Y).

[0019]

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[0020] According to this aspect, by setting the welding length lx between the first end face of the gusset plate and the steel beam and the welding length ly between the second end face and the steel column so as to satisfy Equation (Y), a welded joint having sufficient welding strength can be formed within the range of the axial force of the brace allowed in design. Here, since the welding is double-sided fillet welding or double-sided partial penetration welding, lx and ly, which are the welding lengths on each side, are the welding lengths on one side.

Effect of the Invention

[0021] As can be understood from the above description, according to the connection structure of the steel beam, steel column and brace of the present invention, the steel column and steel beam are welded to the panel core, and the connecting plate at the end of the brace is welded to the steel beam and steel column. Regarding the connection structure of the steel beam, steel column and brace, interference between the connecting plate and the panel core can be prevented, and thus the conventional general evaluation formula can be applied to the yield strength and rigidity of the steel plate forming the panel core.

Brief Description of the Drawings

[0022] [Figure 1] It is a longitudinal sectional view of an example of the connection structure of the steel beam, steel column and brace according to the embodiment. [Figure 2] It is a schematic diagram showing the bending generated in the steel beam and the axial force generated in the brace in a form in which a connecting plate is joined to the steel column and the steel beam. [Figure 3A] It is a longitudinal sectional view of another example of the connection structure of the steel beam, steel column and brace according to the embodiment. [Figure 3B] It is a longitudinal sectional view of still another example of the connection structure of the steel beam, steel column and brace according to the embodiment. [Figure 3C] It is a longitudinal sectional view of still another example of the connection structure of the steel beam, steel column and brace according to the embodiment.

Embodiments for Carrying Out the Invention

[0023] Hereinafter, an example of the connection structure of the steel beam, steel column and brace according to the embodiment will be described with reference to the accompanying drawings. In the present specification and drawings, substantially the same components may be denoted by the same reference numerals, and redundant descriptions may be omitted.

[0024] [Connection Structure of Steel Beam, Steel Column and Brace According to the Embodiment] An example of a joint structure between a steel beam and steel column and a brace according to the embodiment will be described with reference to Figures 1 to 3. Here, Figure 1 is a longitudinal cross-sectional view of an example of a joint structure between a steel beam and steel column and a brace according to the embodiment, and Figure 2 is a schematic diagram showing the bending occurring in the steel beam and the axial force occurring in the brace in a configuration in which a joint plate is joined to the steel column and steel beam. Furthermore, Figures 3A to 3C are all longitudinal cross-sectional views of other examples of the joint structure between a steel beam and steel column and a brace according to the embodiment.

[0025] The illustrated example of the joint structure 100 is a joint structure in which the lower end of the upper column 30A and the upper end of the lower column 30B, both of which are steel columns, are welded to the upper end 12 and lower end 13 of the panel core 10 (four-sided box) which is formed by welding together four steel plates 15 to form a panel zone, a steel beam 40 is joined to the side surface 11 of the panel core 10, and a steel joint plate 60 to which the end 52 of the brace 50 is joined is joined to the upper column 30A and the steel beam 40.

[0026] One of the adjacent steel plates 15 has a groove (not shown) formed in the direction of extension of the steel plate 15, for example, which is tapered and has an inclination angle of about 30 to 50 degrees. By welding the other steel plate 15 through the welded portion in the groove, a hollow, rectangular prism-shaped steel panel core 10 is formed.

[0027] The welded joints joining the steel plates 15 can be formed using various welding methods, including other arc welding methods such as arc spot welding, arc stud welding, gas shielded arc welding, and plasma welding, as well as electroslag welding, electron beam welding, and laser beam welding. However, among these, submerged arc welds formed by submerged arc welding are preferred because they offer the best balance of manufacturing efficiency and quality.

[0028] Four thick steel plates 15 are welded together by submerged arc welding or the like to form a panel core 10, for example, a hollow rectangular prism that is square in plan view. This panel core 10 is of a non-diaphragm type, yet it has extremely high rigidity, and by adjusting the width, length, and thickness of the steel plates 15 as desired, panel cores of various shapes and dimensions can be obtained.

[0029] Here, the panel core 10 may be formed from a square steel pipe instead of the four-sided box shown in the illustration. In this case, the square steel pipe may include an ND core (registered trademark) or a member formed by welding together multiple angle steels, channel steels, and other shaped steel materials.

[0030] Furthermore, the upper column 30A and the lower column 30B are formed from shaped steel materials such as square steel pipes and H-shaped steel. In addition, the steel beam 40 is formed from shaped steel materials such as H-shaped steel. On the other hand, the brace 50 in the illustrated example is a so-called tension brace that resists tensile force. In the example shown in Figure 2, the right-side brace 50 is a tension brace because a horizontal force H is acting on the right side, but when a horizontal force on the left side (not shown) is acting, the left-side brace 50 becomes a tension brace.

[0031] In this illustrated example, a brace 50 is installed within the frame enclosed by the upper column 30A and the steel beam 40, but a separate brace may also be installed within the frame enclosed by the lower column 30B and the steel beam 40. Furthermore, in the illustrated example, two steel beams 40 extending in the left-right direction (at a 180-degree angle) are joined to the panel core 10, but it may also be a configuration in which two mutually orthogonal steel beams 40 are joined, or a configuration in which three steel beams 40 are joined, or four steel beams 40 are joined, or a configuration in which one steel beam 40 is joined.

[0032] The end 52 of the brace 50 is joined to a part of the connecting plate 60 by bolting or welding. The connecting plate 60 is, for example, a gusset plate and has a first end face 62 that is welded to the steel beam 40 and a second end face 64 that is welded to the upper column 30A, which is a steel column.

[0033] In Figure 1, the steel beam 40 and the first end face 62 are welded together by double-sided fillet welding or double-sided partial penetration welding, and are joined via a welded joint 70A having a weld length lx (weld length along the X direction in Figure 1) (only one side of the double-sided weld is shown in the illustration, and a similar welded joint exists on the opposite side).

[0034] Furthermore, the upper column 30A and the second end face 64 are welded together by double-sided fillet welding or double-sided partial penetration welding, and are joined via a welded section 70B having a weld length ly (welding length along the Y direction in Figure 1) (only one side of the double-sided weld is shown in the illustration, and a similar welded section exists on the opposite side).

[0035] In the joining plate 60, a scallop 66 is provided between the first end face 62 and the second end face 64 to prevent interference with the corner on the upper end 12 side of the panel core 10. In the illustrated example, the scallop 66 has a 1 / 4 track shape and a curved surface is provided on a part of it.

[0036] In this case, if the connecting plate 60 is welded to the steel beam 40 and the lower column 30B, the scallop 66 of the connecting plate 60 prevents interference with the corner on the lower end 13 side of the panel core 10.

[0037] Thus, in a steel beam and steel column and brace joint structure 100 in which steel columns 30 are welded to the upper end 12 and lower end 13 of the panel core 10 and steel beams 40 are welded to the side surface 11 of the panel core 10, the joint plate 60 has a first end surface 62 that is welded to the steel beam 40 and a second end surface 64 that is welded to the steel column 30, and a scallop 66 is provided between the first end surface 62 and the second end surface 64 to prevent interference with the panel core 10, thereby preventing interference between the joint plate 60 and the panel core 10.

[0038] If the connecting plate at the end of the brace interferes with the panel core, the out-of-plane bending deformation mode of the steel plate forming the panel core will differ from the mode when there is no interference. In this case, conventional evaluation formulas for assessing the strength and rigidity of the steel plate cannot be applied, and it may be necessary to create a new evaluation formula. In contrast, in the illustrated example of the connecting structure 100, the scallop 66 of the connecting plate 60 prevents interference between the connecting plate 60 and the panel core 10, making it possible to apply conventional evaluation formulas to the strength and rigidity of the steel plate 15 of the panel core 10.

[0039] As shown in Figures 1 and 2, assuming that the axis of the brace 50 is set at an angle θ with respect to the horizontal X-axis direction, the horizontal force H acting during an earthquake generates a compressive axial force N on one of the left and right braces 50 of the upper column 30A, and a tensile axial force N on the other brace 50. Furthermore, the beam end bending bM (beam end moment) of the steel beam 40 acts on the steel plate 15 of the panel core 10.

[0040] Here, the joint structure 100 is designed such that the yield axial force: Ny, which is the maximum value of the axial force N acting on the brace 50, satisfies the following equation (Q1).

[0041]

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[0042] By defining the yield axial force Ny of the brace 50 using equation (Q1) and setting a design axial force limit for the brace 50, the influence of the axial force N of the brace 50 on the steel plate 15 of the panel core 10 can be reduced.

[0043] More specifically, the steel plate 15 may deform due to the bending of the beam ends of the steel beam 40 during an earthquake, but the vertical component of the brace 50 can mitigate the deformation of the steel plate 15.

[0044] For example, in Figure 2, the brace 50 on the right side reduces the compressive force caused by the beam end bend bM by a lateral force Ncosθ opposite to the compressive direction caused by the beam end bend bM, thereby mitigating the deformation of the steel plate 15.

[0045] However, if the axial force N of the brace 50 becomes unexpectedly large, the deformation mode of the steel plate 15 will not only be mitigated but will also become an unexpected deformation mode, and as a result, conventional strength formulas and evaluation formulas will no longer be applicable.

[0046] Therefore, equation (Q1) sets an axial force limit (upper limit) on the brace 50, and assuming that an axial force N below this upper limit acts from the brace 50, the steel plate 15 is set to a deformation mode within the expected range, making it possible to apply conventional yield strength formulas and evaluation formulas to the diaphragm 20.

[0047] Here, a conventional evaluation formula for evaluating the strength and rigidity of the steel plate 15 can be cited as the formula for the beam end moment jMp at the full plastic load capacity of the column-beam joint, as described in 4.2.5 "Non-diaphragm type hollow section column-beam joint" of the Architectural Institute of Japan's Design Guidelines for Steel Structure Joints 2021 revision.

[0048] Using the yield axial force of brace 50, Ny, as defined in equation (Q1), the weld lengths of weld 70A (lx) and weld 70B (ly) are defined such that they satisfy the following equation (Q2).

[0049]

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[0050] By setting the welding length lx between the first end face 62 of the gusset plate 60 and the steel beam 40, and the welding length ly between the second end face 64 and the steel column 30A, such that equation (Q2) is satisfied, welded joints 70A and 70B with sufficient welding strength can be formed within the range of the axial force N of the brace 50 that is permitted in the design.

[0051] Next, other examples of the joint structure according to the embodiment will be described with reference to Figures 3A to 3C.

[0052] The joint structure 100A shown in Figure 3A is a configuration in which a single joint plate 60A is inserted into the interior of the upper column 30A, and the first end faces 62 on the left and right sides are welded to the left and right steel beams 40.

[0053] The brace 50A is a buckling-restrained brace that resists tension and compression. A through diaphragm 20 is provided at an intermediate position on the upper column 30A, and the connecting plate 60A is connected to the through diaphragm 20 and also to the left and right steel beams 40. The connecting plate 60A has a horizontal rib 82, one end of which is connected to the through diaphragm 20, and a vertical rib 84, one end of which is connected to the steel beams 40.

[0054] For example, in a steel beam 40 made of H-shaped steel, the vertical ribs 44 are joined to the web, upper flange, and lower flange at the positions corresponding to the vertical ribs 84.

[0055] The joint plate 60A has a horizontally elongated scallop 66A that does not interfere with the entire upper part of the panel core 10.

[0056] On the other hand, the joint structure 100B shown in Figure 3B, while having buckling-restrained braces 50A, does not have a joint plate that is inserted into the upper column 30A like the joint structure 100A. Instead, similar to the joint structure 100, joint plates 60 are joined to the ends of each brace 50A, and each joint plate 60 is welded to the steel beam 40 and the upper column 30A via welded joints 70A and 70B.

[0057] In the joint structure 100B, a through diaphragm 20 is provided at an intermediate position in the upper column 30A, and the joint plate 60 has a horizontal rib 82 to which one end is joined to the through diaphragm 20 and a vertical rib 84 to which one end is joined to the steel beam 40, and the vertical rib 44 is joined to the web, upper flange and lower flange at the position corresponding to the vertical rib 84 of the steel beam 40 which is made of H-shaped steel.

[0058] Furthermore, the joint structure 100C shown in Figure 3C, like the joint structure 100, has tension braces 50 (for a horizontal force H in the rightward direction in the illustrated example, the right-side brace 50 is the tension brace, and for a horizontal force in the leftward direction (not shown), the left-side brace 50 is the tension brace), but differs from the joint plate 60 which has a quarter-track shaped scallop 66 in that the scallop 66C on the joint plate 60B has a triangular shape with tapered ends.

[0059] Thus, the shape of the scallop that does not interfere with the diaphragm 20 can be set in various ways.

[0060] Other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of symbols]

[0061] 10: Panel core 11: Side view 12:Top edge 13: Bottom edge 15: Steel plate 21: Bottom surface 22:Top surface 30: Steel column 30A: Upper column (steel column) 30B: Lower column (steel column) 40: Steel beam 44: Vertical Rib 50: Brace (Tension brace) 50A: Brace (Buckling-restrained brace) 52: End 60, 60A, 60B: Joint plate (gusset plate) 62: 1st end surface 64:Second end surface 66, 66A, 66B: Scallop 70A, 70B: Welded section 82: Horizontal Ribs 84: Vertical Rib 100, 100A, 100B, 100C: Connection structure between steel beams and steel columns and braces (connection structure) H: Horizontal force N: Axial force bM: Beam end bending

Claims

1. A non-diaphragm type panel core consisting of a four-sided box or square steel pipe formed by welding together four steel plates, to which upper and lower steel columns are welded, to which steel beams are welded, to which steel beams are welded, and to which steel connecting plates to which the ends of braces are welded, to which steel beams are welded, to which steel connecting plates to which the ends of braces are welded, in a steel beam and steel column and brace connection structure, The aforementioned bonding plate is It comprises a first end face that is welded to the steel beam and a second end face that is welded to the steel column, A joint structure for steel beams and steel columns and braces, characterized in that a scallop is provided between the first end face and the second end face to prevent interference with the panel core.

2. The steel beam and steel column and brace joint structure according to claim 1, characterized in that the welded joint between the first end face and the steel beam, and the welded joint between the second end face and the steel column are double-sided fillet welds or double-sided partial penetration welds.

3. The steel beam and steel column and brace connection structure according to claim 2, characterized in that the yield axial force Ny of the brace satisfies the following equation (X). [Math 1]

4. The steel beam and steel column and brace joint structure according to claim 2, characterized in that the welding length lx between the first end face and the steel beam and the welding length ly between the second end face and the steel column satisfy the following formula (Y). [Math 2]

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