Different diameter column joint structure

Abstract

To provide a different-diameter column joining structure in which the lower column and the upper column having different diameters are joined to each other via the diaphragm, and which can smoothly transmit forces to a panel core and a lower column from an upper column without employing a tapered pipe-formed panel core, and also without thickening a plate thickness of an upper diaphragm.SOLUTION: In a different-diameter column joining structure 100, an upper diaphragm 40A and a lower diaphragm 40B are arranged at an upper end 31 and a lower end 32 of a panel core 30A which is composed of a square steel pipe for forming a panel zone, a lower column 10A composed of the square steel pipe is joined to a lower face 43 of a lower diaphragm 40B, an upper column 20A composed of the square steel pipe is joined to an upper face 41 of the upper diaphragm 40A, and a diameter of the upper column 20A is smaller than that of the lower column 10A. A reinforcing rib 50 is joined to a position corresponding to a corner part 23 of the upper column 20A out of a lower face 42 of the upper diaphragm 40A.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a joint structure of columns with different diameters. [Background technology]

[0002] In steel-framed buildings, the panel cores that form the panel zones are fitted with upper and lower diaphragms, with square steel pipe columns (lower columns) joined to the underside of the lower diaphragms and square steel pipe columns (upper columns) joined to the top of the upper diaphragms. In dissimilar diameter column joints, where the upper columns are smaller in diameter than the lower columns, a tapered-tube panel core is used, for example, to connect the panel cores to the upper and lower columns while adjusting the diameters of the upper and lower columns, allowing for smooth transmission of the force acting from the upper columns to the panel core and the lower columns. This tapered-tube panel core is formed, for example, by welding together four trapezoidal steel plates in a plan view. Unlike standard panel cores, this is a custom-made product, which can increase the manufacturing costs of the joint structure.

[0003] On the other hand, there is a connection structure in which the lower column and panel core are made of square steel pipes of the same dimensions, and the thickness of the upper diaphragm is made thicker, for example, to about 40 mm or more (thick plate type), so that the force acting from the upper column can be smoothly transmitted to the panel core and lower column via the upper diaphragm.Unlike general diaphragms, this upper diaphragm made of a thick plate is also a custom-made product, which can be a factor in increasing the manufacturing cost of the connection structure.

[0004] Here, Patent Document 1 proposes a method for predicting the rigidity of a diaphragm and a method for designing plate thickness in a joint between upper and lower steel pipe columns of different diameters. The diaphragm thickness design method uses a method for predicting the rigidity of a diaphragm in a joint between upper and lower steel pipe columns of different diameters that is eccentric in two directions, where two adjacent sides of the cross section of the upper column are aligned with two adjacent sides of the cross section of the lower column, to determine the rigidity of the diaphragm when a design load is applied to the upper column, and selects, from steel plates of multiple standardized thicknesses, a steel plate with the thinnest thickness that satisfies the required rigidity as the diaphragm material. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5864491 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the method for designing the thickness of a diaphragm in a joint between upper and lower steel pipe columns of different diameters described in Patent Document 1, it is possible to design the thickness of a diaphragm in a two-way eccentric different diameter column joint structure with high precision, but it does not disclose a means for achieving smooth force transmission from the upper column to the panel core and lower column without applying a tapered tube type panel core or increasing the thickness of the upper diaphragm, regardless of whether the lower column and upper column in the different diameter column joint structure are eccentric or not.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a different diameter column joint structure in which a lower column and an upper column of different diameters are joined to each other via a diaphragm, which can achieve smooth force transmission from the upper column to the panel core and lower column without applying a tapered tube type panel core or increasing the plate thickness of the upper diaphragm. [Means for solving the problem]

[0008] In order to achieve the above object, one aspect of the different diameter column joint structure according to the present invention is as follows: A dissimilar diameter column joint structure is provided in which an upper diaphragm and a lower diaphragm are provided at the upper and lower ends of a panel core made of a square steel pipe that forms a panel zone, a lower column made of a square steel pipe is joined to the underside of the lower diaphragm, and an upper column made of a square steel pipe is joined to the upper surface of the upper diaphragm, and the upper column has a smaller diameter than the lower column, A reinforcing rib is joined to the lower surface of the upper diaphragm at a position corresponding to the corner of the upper column.

[0009] According to this aspect, in a joint structure in which upper and lower columns made of square steel pipes of different diameters are welded to the upper and lower diaphragms, respectively, of a panel core made of square steel pipes, reinforcing ribs are attached to the underside of the upper diaphragm at positions corresponding to the corners of the upper column, thereby enabling the use of a panel core made of square steel pipes to achieve smooth transmission of force from the upper column to the panel core and lower column without increasing the thickness of the upper diaphragm.Here, the panel core and lower column are made of square steel pipes of the same dimensions, for example.

[0010] Another aspect of the different diameter column joint structure according to the present invention is as follows: A dissimilar diameter column joint structure is provided in which an upper diaphragm and a lower diaphragm are provided at the upper and lower ends of a panel core made of a square steel pipe that forms a panel zone, a lower column made of a square steel pipe is joined to the underside of the lower diaphragm, and an upper column made of an H-shaped steel is joined to the upper surface of the upper diaphragm, and the upper column has a smaller diameter than the lower column, A reinforcing rib is joined to the lower surface of the upper diaphragm at a position corresponding to the end of the flange of the upper column.

[0011] According to this aspect, in a joint structure in which an upper column made of H-shaped steel and a lower column made of square steel pipes of different diameters are welded to the upper and lower diaphragms of a panel core made of square steel pipes, respectively, a reinforcing rib is attached to the underside of the upper diaphragm at a position corresponding to the end of the flange of the upper column. This allows for smooth force transmission from the upper column to the panel core and the lower column without increasing the thickness of the upper diaphragm. For example, if the upper column is a rooftop column, the load it must support is reduced. Therefore, by using an upper column made of H-shaped steel, a joint structure of different diameter columns can be formed with minimal material costs compared to using square steel pipes for the upper column.

[0012] Another aspect of the different diameter column joint structure according to the present invention is as follows: At least the panel core and the lower column are formed of concrete-filled steel pipes in which concrete is filled inside the square steel pipes, The reinforcing ribs are embedded in the concrete.

[0013] According to this aspect, the panel core and the lower column are formed from concrete-filled steel pipes (CFTs), which enhances the axial compressive strength, bending strength, and deformation performance of the panel core and the lower column. Furthermore, the reinforcing ribs attached to the underside of the upper diaphragm are embedded in the concrete inside the panel core, which effectively transmits the forces transmitted from both the upper diaphragm and the reinforcing ribs through the concrete to the rectangular steel pipes forming the panel core and the lower column, which is a concrete-filled steel pipe. Furthermore, because the underside of the upper diaphragm is supported by the entire cross section of the panel core, which is made of concrete-filled steel pipes, downward out-of-plane deformation (depression) of the upper diaphragm is suppressed by the compressive reaction force of the concrete-filled steel pipes. This, combined with the increased out-of-plane rigidity provided by the reinforcing ribs at the legs of the upper column, including the upper diaphragm, allows the upper diaphragm to be made thinner. Here, "at least the panel core and the lower column are formed from concrete-filled steel pipes" includes a configuration in which the panel core and the lower column are formed from concrete-filled steel pipes, and a configuration in which not only the panel core and the lower column but also the upper column is formed from concrete-filled steel pipes.

[0014] Another aspect of the different diameter column joint structure according to the present invention is as follows: In plan view, at least a portion of the reinforcing rib overlaps the corner portion of the upper column or the end portion of the flange.

[0015] According to this embodiment, a reinforcing rib is joined (lapped in plan view) to the underside of the upper diaphragm at a position corresponding to the corner of the upper column made of a square steel pipe or the end of the flange of the upper column made of an H-shaped steel.This effectively reinforces the areas of the upper diaphragm that are most susceptible to damage when force is applied from the upper column, thereby enabling smooth transmission of force to the panel core and lower column while suppressing damage to the upper diaphragm.

[0016] Another aspect of the different diameter column joint structure according to the present invention is as follows: The reinforcing rib is formed by joining steel plates extending in two directions perpendicular to each other, In plan view, the steel plates in two directions are aligned along mutually perpendicular side surfaces at the corner of the upper column made of square steel pipe, or the steel plates on one side of the joint are aligned along the flange of the upper column made of H-shaped steel.

[0017] According to this embodiment, the reinforcing rib is formed by a joint of steel plates extending in two mutually perpendicular directions, and the two-directional steel plates are aligned along the perpendicular side surfaces of the corner portion of the square steel pipe of the upper column, or one of the steel plates is aligned along the flange of the H-shaped steel of the upper column.Therefore, when horizontal forces during an earthquake or strong wind act in two perpendicular directions on the upper column, the joint of steel plates can effectively reinforce the upper diaphragm against the pushing force acting on the upper diaphragm from the leg of the upper column, and smooth force transmission to the panel core and lower column can be achieved while suppressing damage to the upper diaphragm.

[0018] Another aspect of the different diameter column joint structure according to the present invention is as follows: The reinforcing rib is formed from a single steel plate, In plan view, the steel plate is aligned parallel or approximately parallel to the diagonal direction of the upper column.

[0019] According to this aspect, the reinforcing rib formed from a single steel plate is aligned parallel or approximately parallel to the diagonal direction of the upper column when viewed in a plane, so that when horizontal forces during an earthquake or strong wind act in two directions perpendicular to the upper column, the single steel plate can effectively reinforce the upper diaphragm against the pushing force acting on the upper diaphragm from the legs of the upper column, thereby suppressing damage to the upper diaphragm and achieving smooth force transmission to the panel core and lower column.

[0020] Another aspect of the different diameter column joint structure according to the present invention is as follows: The reinforcing rib is formed from a single steel plate, In plan view, the steel plates are aligned parallel or approximately parallel in a direction perpendicular to the diagonal of the upper column.

[0021] According to this aspect, the reinforcing rib formed from a single steel plate is aligned parallel or approximately parallel in a direction perpendicular to the diagonal of the upper column when viewed in a plane. Therefore, when horizontal forces during an earthquake or strong wind act in two directions perpendicular to the upper column, the single steel plate can effectively reinforce the upper diaphragm against the pushing force acting on the upper diaphragm from the legs of the upper column, thereby suppressing damage to the upper diaphragm and achieving smooth force transmission to the panel core and lower column.

[0022] In another aspect of the different diameter column joint structure according to the present invention, The lower end surface of the reinforcing rib is characterized in that the position corresponding to the corner portion of the upper column or the end portion of the flange is a tapered surface that is convex downward.

[0023] According to this aspect, the lower end surface of the reinforcing rib has a downwardly convex tapered surface at a position corresponding to the corner of the upper column made of square steel pipe or the end of the flange of the upper column made of H-shaped steel, thereby preventing the reinforcing rib from impeding the downward or upward flow of concrete filled from the upper column downward or concrete filled from the lower column upward. In particular, when concrete flows upward, the concrete is smoothly guided to the side of the reinforcing rib along the tapered surface at the lower end of the reinforcing rib.

[0024] In another aspect of the different diameter column joint structure according to the present invention, The reinforcing rib has a through hole, and the concrete fills the through hole.

[0025] According to this aspect, the concrete inside the square steel pipe fills the through holes provided in the reinforcing rib, thereby further improving the load transmission performance due to the bearing pressure of the concrete in the through holes.

[0026] Another aspect of the different diameter column joint structure according to the present invention is as follows: The upper column is joined to the upper diaphragm at an eccentric position that is offset from the column center of the lower column in a plan view.

[0027] According to this embodiment, even if the column cores of both the lower column and the upper column are eccentric in one or two directions of the rectangle when viewed in a plane, a reinforcing rib is joined to the underside of the upper diaphragm at a position corresponding to the corner of the upper column, so that a panel core formed from a square steel pipe can be used to achieve smooth force transmission from the upper column to the panel core and lower column without increasing the thickness of the upper diaphragm. [Effects of the Invention]

[0028] As can be understood from the above explanation, according to the different diameter column joint structure of the present invention, in a different diameter column joint structure in which a lower column and an upper column of different diameters are joined to each other via a diaphragm, smooth force transmission from the upper column to the panel core and lower column can be achieved without applying a tapered tube type panel core or increasing the plate thickness of the upper diaphragm. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a perspective view of an example of a joint structure of different diameter columns according to an embodiment. FIG. [Figure 2] 2 is a view taken in the direction of the arrow II in FIG. 1, and is a perspective view of the upper diaphragm as seen from below. [Figure 3A] FIG. 10 is a perspective view of another example of a reinforcing rib, as viewed from below the upper diaphragm. [Figure 3B] FIG. 10 is a perspective view showing yet another example of a reinforcing rib, as viewed from below the upper diaphragm. [Figure 4A] FIG. 10 is a perspective view showing yet another example of a reinforcing rib, as viewed from below the upper diaphragm. [Figure 4B] FIG. 10 is a perspective view showing yet another example of a reinforcing rib, as viewed from below the upper diaphragm. [Figure 5A]FIG. 10 is a plan view of an example of a reinforcing rib in a configuration in which the panel core and the upper column are eccentric in two directions, viewed from the middle of the panel core. [Figure 5B] FIG. 10 is a plan view of another example of a reinforcing rib in a configuration in which the panel core and the upper column are eccentric in two directions, viewed from the middle of the panel core. [Figure 6] This is a plan view of an example of a reinforcing rib in a different diameter column joint structure with another example of an upper column, viewed from the middle of the panel core. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, an example of a joint structure for different diameter columns according to an embodiment will be described with reference to the accompanying drawings. In this specification and the drawings, substantially identical components may be designated by the same reference numerals to avoid redundant description.

[0031] [Different diameter column joint structure according to the embodiment] An example of a joint structure for dissimilar diameter columns according to an embodiment will be described with reference to Fig. 1 to Fig. 6. Here, Fig. 1 is a perspective view of the example of the joint structure for dissimilar diameter columns according to an embodiment, and Fig. 2 is a perspective view taken in the direction of arrow II in Fig. 1, seen from below the upper diaphragm.

[0032] The dissimilar diameter column joint structure 100 includes an upper diaphragm 40A (through diaphragm) and a lower diaphragm 40B (through diaphragm) at the upper end 31 and lower end 32 of a panel core 30A made of square steel pipes that form the panel zone. A lower column 10A made of square steel pipes is joined to the lower surface 43 of the lower diaphragm 40B, and an upper column 20A made of square steel pipes and having a smaller diameter than the lower column 10A is joined to the upper surface 41 of the upper diaphragm 40A. Here, the lower column and the panel core may be made of steel pipes other than square steel pipes. Furthermore, the upper and lower diaphragms may be made of inner diaphragms other than through diaphragms.

[0033] The lower column 10A is a concrete-filled steel pipe (CFT) in which concrete 15 is filled inside a square steel pipe 10. Similarly, the panel core 30A is a concrete-filled steel pipe in which concrete 35 is filled inside a square steel pipe 30, and the upper column 20A is a concrete-filled steel pipe in which concrete 25 is filled inside a square steel pipe 20. Here, the lower column, panel core, and upper column may all be formed only from square steel pipes or steel pipes (a form that is not concrete-filled steel pipes), or only the lower column and panel core may be concrete-filled steel pipes and the upper column may be formed only from square steel pipes or steel pipes, or none of the lower column, panel core, and upper column may be filled with concrete and formed only from square steel pipes or steel pipes.

[0034] The lower column 10A and the panel core 30A are formed from square steel pipes 10, 30 of the same dimensions. In the illustrated example, the web 71 of the beam 70 formed from H-shaped steel is joined to the side of the panel core 30A, the upper flange 72 is joined to the end face of the upper diaphragm 40A, and the lower flange 73 is joined to the end face of the lower diaphragm 40B. Here, "joining" in the following explanation refers in principle to welding, but bolting or the like may also be used if necessary.

[0035] The upper diaphragm 40A and the lower diaphragm 40B are rectangular (square in the illustrated example) in plan view and are formed from steel plates of the same area.

[0036] In the different diameter column joint structure 100, the column centers of the lower column 10A, the panel core 30A, and the upper column 20A are all aligned.

[0037] 2, a reinforcing rib 50A is joined to the underside 42 of the upper diaphragm 40A at a position corresponding to the corner 23 of the upper column 20A. In other words, in a plan view, at least a portion of the reinforcing rib 50A is joined to the underside 42 of the upper diaphragm 40A at a position corresponding to the corner 23 of the upper column 20A in an overlapping manner. Note that the upper column and the panel core may be formed from square steel pipes of the same size, and the lower column may be formed from square steel pipes larger than the panel core. In this configuration, the reinforcing rib 50A is provided on the underside of the lower diaphragm 40B at a position corresponding to the corner of the panel core.

[0038] The reinforcing rib 50A is formed by joining steel plates 51A, 52A extending in two mutually perpendicular directions. The two-directional steel plates 51A, 52A are aligned along mutually perpendicular side surfaces (side surfaces parallel to the X direction and side surfaces parallel to the Y direction) of the square steel pipe 20 at positions on the underside 42 of the upper diaphragm 40A that correspond to the corners 23 of the square steel pipe 20 of the upper column 20A.

[0039] 2, a filling hole 44 is formed in the center of the upper diaphragm 40A, through which the concrete filled in the square steel pipe 20 flows. Furthermore, the square steel pipe 10 of the lower column 10A is originally joined to the lower surface 42 of the upper diaphragm 40A, and air vent holes 45 are formed in the four corners of the upper diaphragm 40A to vent air that accumulates on the lower surface 42 of the upper diaphragm 40A as the concrete filled inside the lower column 10A is poured upward through the filling hole 44.

[0040] In this way, in a plan view, the two-directional steel plates 51A, 52A forming the reinforcing rib 50A are aligned along mutually perpendicular side surfaces at the corner 23 of the upper column 20A, thereby increasing the out-of-plane rigidity of the upper diaphragm 40A. As a result, when a horizontal force H during an earthquake or strong wind as shown in Fig. 1 acts on the upper column 20A and a pressing force P acts on the upper diaphragm 40A from the leg of the upper column 20A, the region of the upper diaphragm 40A near the corner 23 of the upper column 20A is prevented from locally undergoing excessive out-of-plane deformation and breaking, and the load can be smoothly transmitted to the panel core 30A and the lower column 10A via the upper diaphragm 40A.

[0041] In addition, the reinforcing rib 50A improves the out-of-plane rigidity and strength of the upper diaphragm 40A, thereby suppressing deformation of the legs of the upper column 20A during an earthquake, and by mitigating the stress gradient in the legs, the strength of the legs of the upper column 20A can be improved.

[0042] Furthermore, since the underside 42 of the upper diaphragm 40A is supported by the entire cross section of the panel core 30A, which is made of concrete-filled steel pipe, downward out-of-plane deformation of the upper diaphragm 40A is suppressed by the compressive reaction force of the concrete-filled steel pipe 30A, and combined with the increased out-of-plane rigidity due to the reinforcing ribs 50A of the legs of the upper column 20A, including the upper diaphragm 40A, it is also possible to reduce the thickness of the upper diaphragm 40A.

[0043] If the reinforcing rib 50A were not present, as shown in Figure 1, in a case where the upper column 20A is completely inserted into the cross section of the square steel pipe 30 of the panel core 30A due to the different diameter column joint structure, the portion of the upper diaphragm 40A where the pushing force P acts from the upper column 20A is not directly supported by the panel core 30A, so it becomes necessary to make the thickness of the upper diaphragm 40A thick enough to withstand the pushing force P, and the thickness of the upper diaphragm naturally has to be thick.

[0044] For example, if the thickness of the steel plate exceeds 50 mm, there may be limitations on the grade of steel frame fabrication factories that can process it, so being able to reduce the thickness of the upper diaphragm 40A will lead to an increase in the number of steel frame fabrication factories that can process it.

[0045] Furthermore, since the joint body 50A is a component that transmits the pushing force P from the upper column 20A to the panel core 30A and the lower column 10A, the thickness of the steel plates 51A, 52A that make up the joint body 50A is set to a thickness that provides rigidity capable of transmitting the pushing force P, and the dimensions of the joint body 50A are set to a dimension that ensures a welding length capable of transmitting the pushing force P.

[0046] Next, other examples of the reinforcing rib will be described with reference to Figures 3 to 6. Here, Figures 3A to 4B are perspective views of other examples of the reinforcing rib as viewed from below the upper diaphragm.

[0047] 3A and 3B, the lower end surfaces of the joined bodies 50B and 50C that make up the reinforcing rib each have a tapered surface 51a that is convex downward at a position corresponding to the corner portion 23 of the upper column 20A. Note that both Figures 3A and 3B show the upper diaphragm 40A upside down, so the tapered surface 51a is shown as being convex upward, but in the normal form shown in Figure 1, the tapered surface 51a is convex downward.

[0048] In a joined body 50B shown in Fig. 3A, a steel plate 52B having a triangular shape in plan view is joined to a steel plate 51B having a trapezoidal shape in plan view, so that the tip of the joined body 50B is flat. On the other hand, in a joined body 50C shown in Fig. 3B, a steel plate 52C having a triangular shape in plan view is joined to a steel plate 51C having a triangular shape in plan view, so that the tip of the joined body 50C is sharp.

[0049] Both joints 50B and 50C have a downwardly convex tapered surface 51a at a position corresponding to the corner portion 23 of the upper column 20A, so that, for example, concrete filled into the lower column 10A and poured upward can be smoothly guided sideways along the tapered surface 51a, thereby preventing joints 50B and 50C from impeding the flow of concrete.

[0050] Furthermore, through holes 51b are formed in the steel plates 51B, 51C, 52B, and 52C that make up the joints 50B and 50C. The concrete 35 inside the square steel pipes 30 fills the through holes 51b, and the bearing pressure of the concrete in the through holes 51b further improves the load transmission performance of the panel core 30A. Note that similar through holes may also be formed in the steel plates 51A and 52A that make up the joint 50 shown in FIG. 2.

[0051] Next, Fig. 4A and Fig. 4B have in common the point that the reinforcing ribs 50D and 50E are both formed from a single steel plate.

[0052] In the example shown in Fig. 4A, on the underside 42 of the upper diaphragm 40A, the steel plate 50D is aligned parallel or approximately parallel to a direction perpendicular to the diagonal line L of the upper column 20A. Here, "approximately parallel" means that the angle is slightly deviated from parallel within a range of about 20 degrees or less.

[0053] On the other hand, in the example shown in FIG. 4B, on the lower surface 42 of the upper diaphragm 40A, a steel plate 50E is aligned parallel or approximately parallel to the diagonal line L of the upper column 20A.

[0054] In both the forms shown in Figures 4A and 4B, the area on the underside 42 of the upper diaphragm 40A corresponding to the corner 23 of the upper column 20A and its vicinity are effectively reinforced, thereby increasing the out-of-plane rigidity of the upper diaphragm 40A.

[0055] Next, the examples shown in Figures 5A and 5B are both plan views of examples of reinforcing ribs in which the square steel pipes 30 that make up the panel core 30A and the square steel pipes 20 that make up the upper column 20A are eccentric to each other in two directions, as viewed from the middle of the panel core 30A.

[0056] The example shown in FIG. 5A is a configuration in which a connecting body 50A is connected to each corner 23 at an eccentric position of the upper column 20A on the lower surface 42 of the upper diaphragm 40A.

[0057] On the other hand, the example shown in FIG. 5B is a configuration in which steel plates 50E are joined to the lower surface 42 of the upper diaphragm 40A at each corner 23 at an eccentric position of the upper column 20A.

[0058] Here, other joined bodies 50B, 50C or a steel plate 50D may be applied to each corner 23 of the lower surface 42 of the upper diaphragm 40A.

[0059] Even when the panel core 30A (and lower column 10A) and the upper column 20A are eccentric relative to each other in two directions, the reinforcing ribs 50 are joined to each corner 23 of the lower surface 42 of the upper diaphragm 40A at the eccentric position of the upper column 20A, thereby improving the out-of-plane rigidity and yield strength of the upper diaphragm 40A, thereby preventing the upper diaphragm 40A from being locally excessively deformed and damaged, and enabling the load to be smoothly transmitted to the panel core 30A and the lower column 10A via the upper diaphragm 40A. Here, in addition to the two-way eccentricity shown in the example, a one-way eccentricity in only one direction, either the X direction or the Y direction, may also be used.

[0060] On the other hand, the example shown in FIG. 6 is a plan view of an example of a reinforcing rib in a dissimilar diameter column joint structure in which the upper column 20B is formed of H-shaped steel, viewed from the middle of the panel core 30A.

[0061] In the illustrated example, the connector 50A is used as a reinforcing rib, and the connector 50A is joined to the lower surface 42 of the upper diaphragm 40A at a position corresponding to the end 27 of the flange 26 of the upper column 20B.

[0062] More specifically, of the two steel plates 51A and 52A constituting the joined body 50A, the steel plate 51A is aligned along the flange 26 of the H-shaped steel 20B, and the other steel plate 52A is perpendicular to the flange 26.

[0063] In this way, even in a dissimilar diameter column joint structure having an upper column 20B formed from H-shaped steel, the reinforcing rib 50A is joined to the end 27 of the flange 26 of the upper column 20B on the underside 42 of the upper diaphragm 40A, thereby improving the out-of-plane rigidity and strength of the upper diaphragm 40A, thereby preventing the upper diaphragm 40A from undergoing excessive local deformation and breaking, and allowing the load to be smoothly transmitted to the panel core 30A and the lower column 10A via the upper diaphragm 40A.

[0064] The present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form.

[0065] For example, the structure may be a joint structure of columns with different diameters that does not include a panel core. Specific examples include the following forms.

[0066] One embodiment is a different diameter column joint structure in which a lower column with a relatively large diameter is joined to the lower surface of the diaphragm, and an upper column with a relatively small diameter is joined to the upper surface of the diaphragm, The upper column and the lower column are provided with at least a square or circular steel pipe; This is a dissimilar diameter column joint structure, characterized in that a reinforcing rib is joined to the underside of the diaphragm at a position corresponding to the corner of the upper column.

[0067] Another embodiment is a different diameter column joint structure in which a lower column with a relatively large diameter is joined to the lower surface of the diaphragm, and an upper column with a relatively small diameter is joined to the upper surface of the diaphragm, The lower column includes at least a square or circular steel pipe, and the upper column is formed of an H-shaped steel, This is a dissimilar diameter column joint structure, characterized in that a reinforcing rib is joined to the underside of the diaphragm at a position corresponding to the end of the flange of the upper column.

[0068] Furthermore, another form is a different diameter column joint structure, characterized in that the lower column is formed from a concrete-filled steel pipe in which concrete is filled inside the steel pipe. [Explanation of symbols]

[0069] 10: Square steel pipe 10A: Lower column (concrete-filled steel pipe) 15: Concrete 20: Square steel pipe 20A: Upper column (concrete-filled steel pipe) 20B: Upper column (H-shaped steel) 21: Bottom edge 23: Corner 25: Concrete 26: Flange 27:End 30: Square steel pipe 30A: Panel core (concrete-filled steel pipe) 35: Concrete 40A: Upper diaphragm 40B: Lower diaphragm 41:Top surface 42: Bottom surface 44: Filling hole 45: Air vent hole 50: Reinforcement rib 50A, 50B, 50C: Joint (reinforcement rib) 50D, 50E: Steel plate (reinforcement rib) 51A, 51B, 51C, 52A, 52B, 52C: Steel plate 51a: Tapered surface 51b: Through hole 70: Beam (H-shaped steel) 100: Different diameter column joint structure L: Diagonal

Claims

1. A dissimilar diameter column joint structure is provided in which an upper diaphragm and a lower diaphragm are provided at the upper and lower ends of a panel core made of a square steel pipe that forms a panel zone, a lower column made of a square steel pipe is joined to the underside of the lower diaphragm, and an upper column made of a square steel pipe is joined to the upper surface of the upper diaphragm, and the upper column has a smaller diameter than the lower column, A dissimilar diameter column joint structure, characterized in that a reinforcing rib is joined to the lower surface of the upper diaphragm at a position corresponding to the corner of the upper column.

2. A dissimilar diameter column joint structure is provided in which an upper diaphragm and a lower diaphragm are provided at the upper and lower ends of a panel core made of square steel pipes that form a panel zone, a lower column made of square steel pipes is joined to the underside of the lower diaphragm, and an upper column made of H-shaped steel is joined to the upper surface of the upper diaphragm, and the upper column has a smaller diameter than the lower column, A dissimilar diameter column joint structure, characterized in that a reinforcing rib is joined to the lower surface of the upper diaphragm at a position corresponding to the end of the flange of the upper column.

3. At least the panel core and the lower column are formed of concrete-filled steel pipes in which concrete is filled inside the square steel pipes, 3. The joint structure of claim 1, wherein the reinforcing rib is embedded in the concrete.

4. The dissimilar diameter column joint structure according to claim 1 or claim 3 dependent on claim 1, characterized in that, in a plan view, at least a portion of the reinforcing rib overlaps the corner portion of the upper column.

5. A dissimilar diameter column joint structure as described in claim 2 or claim 3 dependent on claim 2, characterized in that, in a plan view, at least a portion of the reinforcing rib overlaps the end of the flange.

6. The reinforcing rib is formed by joining steel plates extending in two directions perpendicular to each other, 3. A dissimilar diameter column joint structure according to claim 1, wherein, in a plan view, the steel plates in two directions are aligned along mutually perpendicular side surfaces at the corner portion of the upper column made of a square steel pipe.

7. The reinforcing rib is formed by joining steel plates extending in two directions perpendicular to each other, A dissimilar diameter column joint structure according to claim 2 or claim 3 dependent on claim 2, characterized in that, in a plan view, the steel plate of one of the joint bodies is aligned along the flange of the upper column made of H-shaped steel.

8. The reinforcing rib is formed from a single steel plate, The joint structure of any one of claims 1 to 3, characterized in that, in a plan view, the steel plate is aligned parallel or approximately parallel to the diagonal direction of the upper column.

9. The reinforcing rib is formed from a single steel plate, The dissimilar diameter column joint structure according to any one of claims 1 to 3, characterized in that, in a plan view, the steel plates are aligned parallel or approximately parallel in a direction perpendicular to the diagonal of the upper column.

10. The lower end surface of the reinforcing rib is a downwardly convex tapered surface at a position corresponding to the corner portion of the upper column.

11. A dissimilar diameter column joint structure as described in claim 2 or claim 3 dependent on claim 2, characterized in that the lower end surface of the reinforcing rib is a tapered surface that is convex downward at a position corresponding to the end of the flange.

12. 4. The joint structure of claim 3, wherein the reinforcing rib has a through hole, and the concrete fills the through hole.

13. The dissimilar diameter column joint structure according to any one of claims 1 to 12, characterized in that the upper column is joined to the upper diaphragm at an eccentric position offset from the column center of the lower column in a plan view.

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