Column-beam joint construction

Abstract

To provide a column-beam joint structure that can reduce manufacturing costs by reducing the plate thickness and excess length of the steel plates that form the panel core. [Solution] A column-beam joint structure 100 is a four-sided box-type, non-diaphragm panel core 10 to which four steel plates 1 and 2 are welded together. The upper and lower ends 12 and 14 of the panel core 10 are welded together to the upper column 20A and lower column 20B, which are steel columns. The steel beam 30 is welded to a position eccentric at least in one direction, vertically or horizontally, from the center of the steel plates 1 and 2. The core depth of the panel core 10 is greater than the beam depth of the steel beam 30, and there are excess lengths 50 and 60 between the upper end 12 and / or lower end 14 of the panel core 10 and the upper end 32 and / or lower end 34 of the steel beam 30. In this column-beam joint structure 100, the bending strength of the steel column 20 is included in the design of the plate thickness tp based on the out-of-plane bending strength of the steel plates 1 and 2.

Description

Technical Field

[0004] , , ,

[0001] The present invention relates to a column-beam joint structure.

Background Art

[0002] In a steel frame building where square steel pipes are applied as steel columns and H-shaped steel is applied as steel beams, a through diaphragm type, an internal diaphragm type, etc. are adopted for the column-beam joints. 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 outside the panel core at positions corresponding to the upper and lower flanges of the steel beam in a panel core made of a square steel pipe. The flange of the steel beam made of H-shaped steel is welded to the through diaphragm projecting outside, 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 internal diaphragm is welded at a position corresponding to the flange of the steel beam with a lower beam deflection, for example, in the panel core.

[0003] However, in these column-beam joint structures using the through diaphragm type or the internal diaphragm type, the manufacturing man-hours tend to increase during manufacturing, and furthermore, 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, the column-beam joint structure described in Patent Document 1 does not take into account cases where the steel beam is eccentric in the vertical or horizontal direction relative to the side surface of the panel core. Therefore, a column-beam joint structure based on a calculation formula for cases where the steel beam is joined to the panel core at an eccentric position is desired.

[0008] Furthermore, the column-beam joint structure described in Patent Document 1 does not take into account the load-bearing capacity of the steel column joined to the panel core in its calculation formula. As a result, the excess length from the upper or lower end of the panel core to the steel column may become long. Therefore, a column-beam joint structure is desired that can further shorten the excess length, thereby reducing the height dimension of the panel core and lowering manufacturing costs.

[0009] The present invention has been made in view of the above problems, and relates to a column-beam joint structure in which a steel beam is welded to a panel core to which a steel column is welded at an eccentric position, and aims to provide a column-beam joint structure that can reduce manufacturing costs by reducing the plate thickness and excess length of the steel plate forming the panel core. [Means for solving the problem]

[0010] To achieve the above objective, one embodiment of the column-beam joint structure according to the present invention is: A column-beam joint structure comprising a four-sided box-type, non-diaphragm panel core, to which four steel plates are welded together, with upper and lower steel columns welded to the upper and lower ends of the panel core, a steel beam welded to a position eccentric at least in one direction (longitudinal or transverse) from the center of the steel plates, the core depth of the panel core being greater than the beam depth of the steel beam, and an excess length between the upper and / or lower ends of the panel core and the upper and / or lower ends of the steel beam, The design of the plate thickness based on the out-of-plane bending strength of the steel plate is characterized in that the bending strength of the steel column is included.

[0011] In this embodiment, a column-beam joint structure is provided in which a steel column is welded to a four-sided box-type non-diaphragm panel core, a steel beam is welded to an eccentric position on a steel plate, and there is an excess length between the upper and / or lower end of the panel core and the upper and / or lower end of the steel beam. In this embodiment, the plate thickness design based on the out-of-plane bending strength of the steel plate includes the bending strength of the steel column, which allows for a thinner plate thickness compared to conventional designs that do not include the bending strength of the steel column, leading to a reduction in the manufacturing cost of the panel core.

[0012] Furthermore, because the bending strength of the steel column is included in the plate thickness design based on the out-of-plane bending strength of the steel plate, the excess length of the excess portion can be shortened while still having an excess length, compared to plate thickness designs based on conventional designs that do not include the bending strength of the steel column. This allows for a shorter height dimension of the panel core, which also contributes to reducing the manufacturing cost of the panel core.

[0013] Here, "steel beams are welded to a steel plate at a position eccentric at least in one direction, either vertically or horizontally, from the center of the steel plate" means that the steel beams are welded to a position eccentric in the vertical direction (up and down) along a vertical line (e.g., a vertical line) passing through the center of the rectangle in plan view (the intersection of the two diagonals of the rectangle), a position eccentric in the horizontal direction (left and right) along a horizontal line (e.g., a horizontal line) passing through the center of the rectangle in plan view, and a position eccentric in both the vertical and horizontal directions.

[0014] In addition to the configuration in which steel beams are welded to all four steel plates forming the panel core, there are also configurations in which steel beams are welded to three steel plates, configurations in which steel beams are welded to two mutually orthogonal steel plates or two opposing steel plates, and configurations in which steel beams are welded to one steel plate. In configurations in which two or more steel beams are welded together, each steel beam may be a stepped beam.

[0015] In this embodiment, submerged arc welding is preferably used for "welded joint." Submerged arc welding involves continuously arranging a large-diameter wire at the welding point and passing a large current to form the weld, resulting in extremely high manufacturing efficiency for column-beam joint structures and the formation of high-quality welds.

[0016] Furthermore, "having excess length between the upper and / or lower end of the panel core and the upper and / or lower end of the steel beam" includes forms in which there is excess length only between the upper end of the panel core and the upper end of the steel beam, forms in which there is excess length only between the lower end of the panel core and the lower end of the steel beam, and forms in which there is excess length both between the upper ends of both and between the lower ends of both.

[0017] The core depth of the panel core is greater than the beam depth of the steel beam, and there is an excess length between the upper and / or lower ends of the panel core and the upper and / or lower ends of the steel beam, allowing for a rigid connection between the panel core and the steel beam. Furthermore, if seismic reinforcement braces such as buckling-restrained braces exist within the steel frame, the seismic reinforcement braces can be connected to the excess length. If there is no excess length, it may be necessary to connect the seismic reinforcement braces to, for example, the steel column and implement reinforcement measures at the connection point on the steel column.

[0018] Furthermore, other embodiments of the column-beam joint structure according to the present invention are: The aforementioned steel column is formed from a square steel pipe, The aforementioned steel beam is formed from H-shaped steel, The rectangular steel pipe is characterized by being located inside the thickness of the panel core.

[0019] According to this embodiment, since the steel columns are formed from square steel pipes and the steel beams are formed from H-shaped steel, a highly versatile and rational column-beam joint structure can be formed in which steel materials are appropriately placed.

[0020] Furthermore, since the square steel pipe is present inside the thickness of the panel core, that is, the thickness of the steel plate is set to be thicker than the thickness of the steel frame column made of the square steel pipe, a high-rigidity column-beam joint structure can be formed while being a non-diaphragm type.

[0021] In addition, another aspect of the column-beam joint structure according to the present invention is characterized in that the plate thickness tp of the steel plate satisfies the following two conditional expressions (A) and (B) based on the yield line theory.

Equation

[0022] According to this aspect, while including the bending strength of the steel frame column, the plate thickness of the steel plate forming the panel core is set to satisfy the conditional expression based on the yield line theory, so that a column-beam joint structure having sufficient structural strength can be provided while the panel core applies the non-diaphragm type.

Advantages of the Invention

[0023] As can be understood from the above description, regarding the column-beam joint structure in which the steel beam is welded to an eccentric position with respect to the panel core to which the steel frame column is welded, it is possible to reduce the plate thickness and the extra length of the steel plate forming the panel core, and to reduce the manufacturing cost.

Brief Description of the Drawings

[0024] [Figure 1] It is a perspective view of an example of a panel core forming a column-beam joint structure according to an embodiment. [Figure 2] It is a view taken in the direction of arrow II in FIG. 1. [Figure 3] It is a perspective view of an example of a column-beam joint structure according to an embodiment. [Figure 4] It is a view taken in the direction of arrow IV in FIG. 3. [Figure 5] It is a cross-sectional view taken along the line V-V in FIG. 3. [Figure 6]This is a diagram illustrating the out-of-plane bending yield mechanism. [Modes for carrying out the invention]

[0025] The column-beam joint structure according to the embodiment will be described below with reference to the attached drawings. In this specification and the drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0026] [Column-beam joint structure according to an embodiment] An example of a column-beam joint structure according to the embodiment will be described with reference to Figures 1 to 6. Here, Figure 1 is a perspective view of an example of a panel core forming the column-beam joint structure according to the embodiment, and Figure 2 is a view taken in the direction of arrow II in Figure 1. Figure 3 is a perspective view of an example of a column-beam joint structure according to the embodiment, and Figures 4 and 5 are a view taken in the direction of arrow IV and VV in Figure 3, respectively. Furthermore, Figure 6 is a diagram illustrating the out-of-plane bending yield mechanism.

[0027] The steel panel core 10 is formed from a total of four steel plates 1 and 2, two of each with different widths. At both ends of the relatively short steel plate 2, a tapered groove 2a with an inclination angle of approximately 30 to 50 degrees is formed along the extension direction of the steel plate 2. The long steel plate 1 and the short steel plate 2 are arranged as shown in Figure 1, and backing plates 4 are placed along the short steel plate 2 at the inside of the four corners. Welds 3 are formed in the grooves 2a, forming a hollow, rectangular prism-shaped steel panel core 10 (four-sided box).

[0028] As shown in Figure 2, the planar shape of the panel core 10 is a square with side length Dp. However, depending on the cross-sectional shape of the upper and lower columns joined to the upper end 12 and lower end 14 of the panel core 10, the panel core may have a shape other than a square, for example, a rectangular planar shape. Furthermore, the thickness tp of the steel plates 1 and 2 is thicker than that of a typical panel core equipped with a diaphragm. This thickness tp will be explained in detail below.

[0029] The welded joint 3 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, the submerged arc welded joint 3 is formed using submerged arc welding, which offers the best balance of manufacturing efficiency and quality.

[0030] Submerged arc welding is a welding method in which granular flux is scattered along the weld line, a solid wire is continuously supplied through it, and an arc is generated between the base metal and the wire while they are covered in flux, melting both and joining them together.

[0031] Submerged arc welding is more than ten times more efficient than conventional manual welding because it uses a large diameter wire and a large current. Furthermore, it generally penetrates deeply, resulting in stable weld quality, a uniform and aesthetically pleasing bead appearance, and the formation of highly reliable welded joints. For example, it is possible to manufacture panel cores 10 as shown in Figure 1 continuously by producing pieces several times longer than the panel core 10 shown in Figure 1 and then cutting them. This manufacturing method allows for even more efficient production of panel cores 10.

[0032] The panel core 10, a hollow rectangular prism with a square shape in plan view, is formed by joining four thick steel plates 1 and 2 together at submerged arc welds 3. Despite being a non-diaphragm type, it is an extremely rigid and highly efficient panel core to manufacture. Furthermore, by adjusting the width, length, and thickness of the steel plates 1 and 2 as desired, panel cores of various shapes and dimensions can be obtained.

[0033] Furthermore, as explained below, in designing the plate thickness of the steel plates 1 and 2 forming the panel core 10 in the illustrated example based on their out-of-plane bending strength, the bending strength of the steel column 20 (see Figure 3) welded to the panel core 10 is included (considered). Therefore, the plate thickness is thicker than that set based on a design that does not consider the bending strength of the steel column 20.

[0034] Furthermore, the excess lengths of the excess sections 50 and 60 (see Figure 5) between the upper and lower ends of the steel plates 1 and 2 and the upper and lower ends of the steel beams 30 (see Figure 3) welded to the steel plates 1 and 2 are shorter than the excess lengths of the excess sections set based on a design that does not take into account the bending strength of the steel columns 20.

[0035] Thus, by considering the steel columns 20 in the design based on the out-of-plane bending strength of the steel plates 1 and 2, the thickness of the steel plates 1 and 2 can be made as thin as possible, although still thicker than the thickness of the steel columns 20. This allows the excess length between the upper or lower ends of both the steel plates 1 and 2 and the steel beams 30 to be shortened as much as possible. As a result, the material cost of the steel plates 1 and 2 can be reduced, and the manufacturing cost of the panel core 10 can be reduced.

[0036] Since the panel core 10 does not have a diaphragm inside, concrete can be easily filled into the panel core 10, for example, when taking measures to further increase its rigidity by filling the panel core 10 with concrete.

[0037] Although not shown in the diagram, a panel core with the same shape and dimensions as the panel core 10 shown in Figure 1 can also be obtained by using four steel plates of the same type, each steel plate having a groove at only one end, and welding the grooves together with the sides of adjacent steel plates.

[0038] In the column-beam joint structure 100, steel beams 30 made of H-shaped steel are welded to each steel plate 1, 2 of the panel core 10 that forms the panel zone, and square steel pipes of the same cross-sectional shape, which become the upper column 20A and lower column 20B, are welded to the upper end 12 and lower end 14 of the panel core 10, respectively. Here, although not shown in the figures, each web and flange of the steel beam 30 is connected to each steel plate 1, 2 by full penetration welding. In addition, the steel columns 20 made of square steel pipes are also connected to the end faces of each steel plate 1, 2 by full penetration welding.

[0039] Since the column-beam joint structure 100 is a non-diaphragm type structure, the scallops that were required in the case of a diaphragm structure, which are provided at the top and bottom ends of the web of the steel beam, can be eliminated.

[0040] As shown in Figure 4, the overall dimensions of both the panel core 10 and the steel column 20, as well as the plate thickness tp of the steel plates 1 and 2, are set such that the cross-section of the steel column 20 is completely contained within the cross-section of the panel core 10.

[0041] The plate thickness tp of steel plates 1 and 2 is such that the cross-section of the steel column 20 is completely accommodated, and is greater than the thickness tc of the steel column 20. Also, as shown in Figure 4, the steel column 20 has curved sections (R sections) with a radius of curvature r at all four corners, and is a steel pipe column that is square in plan view with side length Dp.

[0042] For square steel pipes 20, cold-formed square steel pipes for building structures, such as BCR (Box Column Roll, registered trademark) and BCP (Box Column Press, registered trademark), are used. These are square steel pipes manufactured by the Iron and Steel Federation of Japan, based on SN material (building structural steel). In addition, square steel pipes 20 can also be made from JIS products based on JIS G 3466 (square steel pipes for general structural use), such as STKR400 and STKR490.

[0043] Since the entire cross-section of the rectangular steel pipe 20, which has rounded corners in a typical configuration, is completely housed within the cross-section of the panel core 10, axial force, bending, and other forces from the rectangular steel pipe 20 can be effectively transmitted to the panel core 10.

[0044] As shown in Figure 5, the column-beam joint structure 100 is formed by welding steel beams 30A and 30B, both made of H-shaped steel with a beam depth of H2, to opposing side surfaces 11 of the panel core 10, and welding steel columns, upper column 20A and lower column 20B, to the upper end 12 and lower end 14 of the panel core 10.

[0045] The illustrated column-beam joint structure 100 has a stepped beam in which the joint positions of two steel beams 30A and 30B with the same beam depth are offset vertically relative to the side surface 11 of the panel core 10. With respect to the vertical center position CP of the side surface 11 of the panel core 10, one steel beam 30A is offset upward by ΔH, and the other steel beam 30B is offset downward by ΔH. Furthermore, neither steel beam 30A nor 30B is offset horizontally relative to the side surface 11. Therefore, they are joined to the side surface 11 of the panel core 10 in an eccentric state only in the vertical direction.

[0046] Furthermore, the eccentricity of the steel beam 30 joined to the side surface 11 of the panel core 10 may be eccentric in the lateral direction, or it may be eccentric in both the vertical and lateral directions.

[0047] Furthermore, multiple steel beams with different beam depths may be joined to each side 11 of the panel core 10. In addition to the example shown in which two steel beams 30 are joined to a pair of opposing side 11, there may also be configurations in which two steel beams 30 are joined to adjacent side 11 of the panel core 10 in a manner that is perpendicular to each other, configurations in which steel beams 30 are joined to three side 11, configurations in which steel beams 30 are joined to four side 11, or configurations in which steel beams 30 are joined to any one side.

[0048] The height H1 of the panel core 10 is set higher than the beam depth H2. A relatively short excess length lp is provided between the upper end 32 of one steel beam 30A and the upper end 12 of the panel core 10, and a relatively long excess length lp' is provided between the lower end 34 of the steel beam 30A and the lower end 14 of the panel core 10, and a relatively long excess length lp' is provided between the upper end 32 of the other steel beam 30B and the upper end 12 of the panel core 10, and a relatively short excess length lp is provided between the lower end 34 of the steel beam 30B and the lower end 14 of the panel core 10, and a relatively short excess length lp is provided.

[0049] Thus, when there are excess lengths lp and lp' between the panel core 10 and the steel beams 30A and 30B, these excess lengths lp and lp' satisfy the yield bending strength formula based on the yield line theory, thereby enabling a rigid connection between the panel core 10 and each of the steel beams 30A and 30B.

[0050] Furthermore, although not shown in the diagram, if seismic reinforcement braces (buckling-restrained braces) are present within the steel frame structure, these seismic reinforcement braces can be connected to the excess sections 50 and 60. This eliminates the need to connect the seismic reinforcement braces to the steel column 20 while simultaneously implementing reinforcement measures for the steel column 20, which is necessary when the excess sections 50 and 60 are not present.

[0051] [Method for setting panel core thickness based on yield line theory] In designing the plate thickness tp of the steel plates 1 and 2 of the panel core 10 (four-sided box) that forms the column-beam joint structure 100, the plate thickness is set to satisfy the following two conditional equations (Q1) and (Q2) based on yield line theory, which include the bending strength of the steel column 20. Here, conditional equation (Q1) is an equation that satisfies the condition that the out-of-plane bending yield strength is equal to or greater than the yield bending moment of the beam, and conditional equation (Q2) is an equation that satisfies the condition that the maximum out-of-plane bending strength is equal to or greater than the product of the beam's full plastic bending moment and the joint coefficient (ultimate strength). The plate thickness that satisfies both conditions is determined, and the plate thickness of the steel plates 1 and 2 is set to be equal to or greater than the calculated plate thickness.

[0052]

number

[0053] To determine these two conditions, calculations based on yield line theory are performed. Here, Figure 6 illustrates the out-of-plane bending yield mechanism, where Figure 6(a) is a front view of the panel core seen from the steel beam side, Figure 6(b) is a top view of the panel core seen from above, and Figure 6(c) is a side view of the panel core seen from the side.

[0054] In equations (Q1) and (Q2) above, the right-hand side of each equation is the product of the yield bending moment of the steel beam, the full plastic bending moment, and the joint coefficient (ultimate strength). Equations (Q1) and (Q2) are conditional equations that the sum of the bending strengths of the steel beam and the panel core is greater than the yield bending moment or full plastic moment of the steel beam. The left-hand side of equations (Q1) and (Q2) includes the plate thickness tp of the steel plates 1 and 2 that form the panel core 10. The thickness of the panel core 10 is determined by finding the plate thickness tp that satisfies both of these equations.

[0055] The left-hand sides of equations (Q1) and (Q2) above both include terms for the yield strength of the steel column 20, such as the yield bending moment and the full plastic bending moment of the steel column 20, assuming that the steel beam 30 is joined to the panel core 10 at an eccentric position. By taking the yield strength of the steel column 20 into account in this way, it becomes possible to set the plate thickness tp of the steel plates 1 and 2 that satisfy the two conditional equations to be thinner.

[0056] Furthermore, in setting the excess lengths lp and lp' of the excess lengths 50 and 60 of the panel core 10, consider the case in Figure 6 where the yield line PP' occurs on the steel column 20 side of the boundary between the steel panel core 10 and the steel column 20. Determine the yield bending moment of the steel panel core 10 and steel column 20 per unit length of the yield line PP', and calculate the excess lengths lp and lp'.

[0057] By taking into account the yield strength of the steel column 20 when calculating these excess lengths lp and lp', it becomes possible to set the excess lengths lp and lp' of the excess section to be shorter.

[0058] In the column-beam joint structure 100 having the excess lengths lp and lp' set in this manner, the joint structure between the panel core 10 and each steel beam 30 can be made rigid, and furthermore, the presence of the excess length lp (or lp') makes it possible to make the plate thickness of the panel core 10 relatively thinner compared to the case without the excess length.

[0059] Furthermore, 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]

[0060] 1,2: Steel plate 2a: Bevel 3: Welded joint (submerged arc weld) 4: Backing metal 10: Panel core (4-sided box) 11: Side view 12:Top edge 14: Bottom edge 20: Steel column (square steel pipe) 20A: Upper column (steel column, square steel pipe) 20B: Lower column (steel column, square steel pipe) 30, 30A, 30B: Steel beam (H type steel) 32:Top edge 34: Bottom edge 50,60:Extra length 100: Column beam joint structure

Claims

1. A column-beam joint structure comprising a four-sided box-type, non-diaphragm panel core, to which four steel plates are welded together, with upper and lower steel columns welded to the upper and lower ends of the panel core, a steel beam welded to a position eccentric at least in one direction (longitudinal or transverse) from the center of the steel plates, the core depth of the panel core being greater than the beam depth of the steel beam, and an excess length between the upper and / or lower ends of the panel core and the upper and / or lower ends of the steel beam, A column-beam joint structure characterized in that the design of the plate thickness based on the out-of-plane bending strength of the steel plate includes the bending strength of the steel column.

2. The aforementioned steel column is formed from a square steel pipe, The aforementioned steel beam is formed from H-shaped steel, The column-beam joint structure according to claim 1, characterized in that the rectangular steel pipe is located inside the thickness of the panel core.

3. The column-beam joint structure according to claim 2, characterized in that the plate thickness tp of the steel plate satisfies the following two conditional equations (A) and (B) based on yield line theory. [Math 1]

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