JP2014163201A - Square steel pipe column with column head part column-beam joining part core and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a square steel pipe column with a column head part column-beam joining part core, excellent in workability when executing molten galvanization, capable of the excellent molten galvanization without staying zinc inside, and capable of securing bearing force required for the column-beam joining part core even if an opening part of a predetermined extent is provided in a reinforcement plate.SOLUTION: In the square steel pipe column 16 with the column head part column-beam joining part core, the column-beam joining part core 12 of a non-diaphragm form is provided in a column head part of a square steel pipe column 3, and the column-beam joining part core 12 is a structure for welding-joining the reinforcement plate 15 to an upper end surface of a core material 12a being a short length thick square steel pipe, and in the reinforcement plate 15, an opening part composed of a circular hole 15b is provided only in a transplanter in the vicinity of an inner peripheral corner part of the core material 12a, and the molten galvanization is applied by being immersed in a molten galvanization tank in a state of welding-joining an upper end surface of the square steel pipe column 3 to a lower end surface of the column-beam joining part core 12.

Description

  The present invention relates to a square steel pipe column with a column head column beam joint core in which a non-diaphragm type column beam joint core is provided at a column head of a square steel tube column, and a method of manufacturing the same.

As a column beam joint structure in a building structure that uses a square steel pipe for the column and an H-shaped steel for the beam, the square steel pipe columns on the upper and lower floors are welded and joined via a separate column beam joint core. There is a structure in which an H-shaped steel beam is welded to the part core.
This type of column-beam joint core generally has a structure in which a diaphragm is welded and fixed to a short square steel pipe as a reinforcement in order to make a rigid joint that can sufficiently transmit stress such as bending moment acting on the beam to the column. Used.
As a beam-column joint core with a diaphragm, a through-diaphragm column beam-joint core with a diaphragm welded and fixed to both end faces of a short rectangular steel pipe is widely used, but the diaphragm is made thick to ensure rigidity In some cases, a short thick-walled square steel pipe without a so-called non-diaphragm column beam joint core may be used. The short square steel pipe itself of the column beam joint core is called a core material.
In the case of a non-diaphragm type column beam joint core, the out-of-plane deformation strength of the steel pipe wall of the column with respect to the beam end moment is considered as the rigidity required for the beam-column joint.

FIG. 1 shows a column beam joint core used for a column head. FIG. 1A shows a through-diaphragm-type column beam joint core 1 in which diaphragms 1b and 1c are welded and fixed to both upper and lower end surfaces of a core material 1a which is a short rectangular steel pipe. FIG. 1 (b) shows a non-diaphragm-type column beam joint core 2, which consists only of a core material 2a which is a short thick-walled square steel pipe and has no diaphragm. 3 is a square steel pipe column and 4 is a beam of H-section steel. The upper flange of the H-shaped steel beam 4 is indicated by 4a, and the lower flange is indicated by 4b.
When the column beam joint core is provided at the column head of the square steel pipe column, the design method differs between the case of the through-diaphragm type column beam joint core 1 and the case of the non-diaphragm type column beam joint core 2. That is, in the case of the through diaphragm type, the upper and lower diaphragms 1b and 1c directly bear the horizontal force acting from the upper and lower flanges 4a and 4b of the beam 4 (stress is transmitted through the diaphragm). The design method (the same design method as that of the column beam joint core in the middle part of the column that is not the column head) can be used.
However, in the case of the non-diaphragm type column beam joint core 2, the column beam joint core in the middle portion of the column is shown in FIGS. 2 (a) and 2 (b) from the upper and lower flanges 4a and 4b, respectively. The load load for the acting horizontal force is often a load load using not only the column-beam joint core but also the lower floor column 3 and the upper column 3 ', and FIG. 2 (c) without the upper column 3'. In the column-beam joint core of the column head as in (d), the out-of-plane deformation resistance decreases. Therefore, a reinforcing plate 5 having a diameter slightly smaller than the outer diameter of the core material is fixed to the upper end surface of the column beam joint core 2 by fillet welding, and the out-of-plane deformation resistance is reduced because the reinforcing plate 5 has no upper floor column. The method of paying is generally adopted. In addition, the reinforcement board 5 is a simple square board | plate material which does not open a hole, when not hot-dip galvanizing to the column beam junction part core 2. FIG.
2 (b) and 2 (d), the white arrow indicates the load acting on the tube wall surface of the core material 2a from the upper flange 4a or the lower flange 4b of the beam, and the broken lines in (a) and (c) indicate the tube wall surface. 2 schematically shows out-of-plane deformation as viewed from the front, and broken lines in (b) and (d) schematically show the out-of-plane deformation state seen in the tube wall cross section.

In "Building Construction Standard Specification JASS6 Steel Construction: Architectural Institute of Japan", "Technical Guidelines for Steel Construction-Factory Construction: Architectural Institute of Japan", diaphragms inside closed-section steel pipes, square steel pipes and welded assembly box-shaped sections In addition, when hot-dip galvanizing is performed with an end plate attached, it is described that it is necessary to provide openings for zinc inflow and outflow and air venting. In this case, it is desirable that the total area of the openings is at least 1/3 of the cross-sectional area of the closed cross section. According to the description described in the case of the through diaphragm type as a specific example, as shown in FIG. 3, as an opening provided in the diaphragms 1b and 1c, a large circular hole 1d at the center of the diaphragm, a core material (column beam joint) A pattern in which small circular holes 1e are formed in the vicinity of the four inner peripheral corners of the short rectangular steel pipe 1a of the core is recommended. That is, the total area of one large circular hole 1d and four small circular holes 1e is set to 1/3 or more with respect to the cross-sectional area of the closed cross section (empty horizontal cross-sectional area in the core material). 4 shows only the through-diaphragm-type column beam joint core 1 of FIG. 3 in a concise manner. FIG. 4A is a plan view, FIG. 4B is a cross-sectional view, and FIG. 4C is a bottom view.
The column beam joint core described as a specific example in the steel frame construction technical guideline is a through diaphragm type, but it is considered to be the same when the above-described reinforcing plate 5 is provided in a non-diaphragm column beam joint core. As shown in FIG. 5A, the reinforcing plate 5 has a large circular hole 5d at the center and small circular holes 5e in the vicinity of the four inner peripheral corners of the core material 2a. FIGS. 5B and 5C are the same as FIGS. 2C and 2D, respectively.

  Although there is no patent document regarding a technique for hot dip galvanizing a non-diaphragm column head column beam joint core, there is JP 2010-236206 as a patent document regarding a required rigidity as a column beam joint core.

JP 2010-236206 A

  When hot-dip galvanized through-diaphragm-type column beam joint cores with reinforcing plates at both end faces, the upper and lower diaphragms have openings for zinc inflow and outflow in the pattern shown in FIG. 3 (FIG. 4). Even when the opening area is 1/3 or more of the cross-sectional area of the closed cross section, when the member is pulled up from the plating tank, zinc easily accumulates in the corners of the rectangular reinforcing plate, and is completely However, there is a problem that it is difficult to extract zinc from the inside of the steel pipe.

When the openings 5d and 5e are provided in the pattern of FIG. 5 (a) on the reinforcing plate 5 of the column-beam joint core 2 for the column head of the non-diaphragm type, there are the following problems.
That is, the diaphragms 1b and 1c of the through-diaphragm column beam joint core 1 are directly joined to the beam flanges 4a and 4b at the beam flange joint positions as described in FIG. In contrast to the member that restrains the out-of-plane deformation of the smoothed column-beam joint core 1, the reinforcing plate 5 of the non-diaphragm column head-column joint core 2 is shown in FIGS. (C) As explained in (d), since it is a member that bears the strength reduction that is bonded to the upper end surface of the core material located slightly above the beam flange bonding position, and the upper column is not bonded to the upper side, If an opening having an area of 1/3 or more of the closed cross section is provided in the reinforcing plate 5 in a pattern as shown in FIG. 5 (a), it is considered that the proof stress of the column beam joint is significantly reduced.

  The present invention has been made based on the above background, and a rectangular steel pipe column with a column head column beam joint core in which a column beam joint core for a column head having a reinforcing plate in a non-diaphragm type is welded and fixed to a square steel pipe column. When the hot dip galvanizing is performed, the workability is good and the hot dip galvanizing can be performed without accumulating zinc inside, and the reinforcing plate is provided with an opening of a predetermined width. It is another object of the present invention to provide a square steel pipe column with a column head column beam joint core that can ensure the proof stress required for the column beam joint core, and a method of manufacturing the same.

Invention of Claim 1 which solves the above-mentioned subject is a square steel pipe column with a column head column beam joint core in which a non-diaphragm type column beam joint core is provided at the column head of a square steel tube column,
The column beam joint core has a structure in which a square reinforcing plate is welded to the upper end surface of a core material that is a short thick square steel pipe having an aspect ratio of 1: 1 in a plan view. An opening consisting of a circular hole is provided only in the vicinity of the inner peripheral corner of the core material,
The hot-dip galvanization is performed by dipping in a hot-dip galvanizing bath in a state where the upper end surface of the rectangular steel pipe column is welded to the lower end surface of the column-beam joint core.

  Claim 2 is a square steel pipe column with a column head column beam joint part core according to claim 1, and the circular holes provided in the reinforcing plate are respectively provided in the vicinity of four inner peripheral corners of the core material, The total area of each circular hole is 1/3 or more of the empty horizontal cross-sectional area in the core material.

Claim 3 is a square steel pipe column with a column head column beam joint core according to claim 1 or 2, wherein the reinforcing plate has at least two beams joined to the pipe wall surfaces on the left and right sides of the square steel pipe column. The provided circular hole is characterized in that the size and the position are symmetrical with respect to two center lines orthogonal to each other that pass through the center of the reinforcing plate and are parallel to the side of the reinforcing plate.
A fourth aspect of the present invention provides a square steel pipe column with a column head column beam joint core according to claim 1, wherein the square plate has only two beams respectively joined to mutually perpendicular pipe wall surfaces. The circular hole is characterized in that the size and position are symmetrical with respect to the reinforcing plate diagonal in the direction of the bisector of the angle formed by the two beams.

Claim 5 is a square steel pipe column with a column head column beam joint core according to any one of claims 1 to 3,
The reinforcing plate has a thickness of 8% or more of the outer diameter of the core material.

Claim 6 is a square steel pipe column with a column head column beam joint core according to any one of claims 1 to 4.
The core material is characterized in that the plate thickness is 4 mm or more thicker than the plate thickness of the lower rectangular steel pipe column joined to the lower end surface.

The invention according to claim 7 is a column head for manufacturing a square steel pipe column with a column head column beam joint core provided with a non-diaphragm type column beam joint core at a column head of a square steel tube column having a square shape. A method of manufacturing a square steel pipe column with a core-column joint core,
In the square steel plate, a reinforcing plate having a plurality of circular holes is formed by opening a circular hole so as to be attached near the inner peripheral corner of the core material,
The reinforcing plate is welded to the upper end surface of the core material which is a short thick-walled square steel pipe having an aspect ratio of 1: 1 in plan view to constitute the column beam joint core,
Welding the upper end surface of the rectangular steel pipe column to the lower end surface of the column beam joint core;
The integral beam-column joint core and rectangular steel pipe column are immersed in a hot dip galvanizing bath in an inclined state with the reinforcing plate side on the upper side and the lower end of the rectangular steel tube column on the lower side, and are pulled up from the hot dip galvanizing bath in the same inclined state. And hot dip galvanizing.

According to the invention of claim 1 or claim 7, in a state in which the square steel pipe column is welded and fixed to the lower end surface of the column beam joint core in which the reinforcing plate having the opening is welded and fixed to the upper end surface, that is, the column head column beam. Since hot dip galvanization is performed in the state of a rectangular steel pipe column with a joint core, good hot dip galvanization can be performed with good workability.
That is, when placed in a hot dip galvanizing tank in an inclined state with the reinforcing plate side (column beam joint core side) on the upper side and the lower end of the square steel pipe column on the lower side, the lower side is a long square steel pipe column but is closed. On the other hand, on the upper side, the opening of the reinforcing plate performs the air venting action, so that zinc penetrates smoothly into the pipe and is filled. Also, when pulled up from the plating tank in a similar inclined state, the opening of the reinforcing plate acts as an air supply into the pipe and the zinc in the pipe vigorously escapes from the lower end opening of the steel pipe, improving work efficiency, Zinc does not collect at the lower end of a square steel pipe column that is a simple cylinder. Furthermore, since air flows in and out smoothly from the opening of the reinforcing plate, it is possible to prevent the occurrence of plating cracks in the square steel pipe column.

In addition, the reinforcing plate is provided with an opening made of a circular hole only in the vicinity of the inner peripheral corner portion of the core material, and since there is no hole in the central portion of the reinforcing plate, the fillet welded portion around the reinforcing plate is provided. Can be transmitted through the central part of the reinforcing plate. Therefore, the load that the reinforcing plate can bear against the horizontal force acting from the beam flange does not decrease much compared to the case where a large circular hole is provided in the central portion of the reinforcing plate, and therefore the plate thickness is extremely increased. Even if it does not exist, it becomes possible to make the reinforcing plate bear the same load as the load of the upper floor pillar in the middle part of the pillar.
As a result, as in claim 2, the total area of the circular holes respectively provided in the vicinity of the four inner peripheral corners of the core material is an extremely large total area of 1/3 or more of the empty horizontal sectional area in the core material. Even if a wide opening is provided, it is possible to ensure the proof stress required for the non-diaphragm column head column beam joint.

According to claim 3, in the case of having at least two beams joined to the left and right pipe wall surfaces of the square steel pipe column, the circular hole provided in the reinforcing plate passes through the center of the reinforcing plate and the side of the reinforcing plate. Since both the two center lines that are orthogonal to each other are symmetrical in size and position, stress that is biased to the reinforcing plate due to the load from the beam is less likely to occur, which is favorable in securing the proof stress. Moreover, it can be said that it is preferable for uniformly attaching zinc when it is immersed in a plating tank and hot dip galvanized.
According to claim 4, in the case of having only two beams respectively joined to the mutually perpendicular tube wall surfaces of the square steel pipe column, the circular hole provided in the reinforcing plate is bisected at an angle formed by the two beams. Since the size and position are symmetrical with respect to the diagonal line of the reinforcing plate in the linear direction, as described above, stress that is biased to the reinforcing plate by the load from the beam is less likely to occur, which is favorable in securing the proof stress. Moreover, it can be said that it is preferable for uniformly attaching zinc when it is immersed in a plating tank and hot dip galvanized.

  As in claim 5, when the thickness t ′ of the reinforcing plate is 8% or more of the outer diameter of the core material, the details will be described later, but for the column beam joint core having the reinforcing plate provided with an opening, It becomes possible to give a proof strength equivalent to the proof strength of a column beam joint core having a reinforcing plate having a predetermined thickness (standard thickness t) without an opening.

  If the thickness of the core material is as described in claim 6, performance as a non-diaphragm column beam joint core can be secured.

The column beam joint core of the column head will be described. (A) shows a case of a through diaphragm type, and (B) shows a case of a non-diaphragm type. Explains the load bearing of the non-diaphragm column beam joint core. (B) and (B) are for the middle part of the column, (C) and (D) are for the column head The figure is shown. Used in the explanation of the necessity to provide openings in diaphragms etc. when hot-dip galvanized by attaching diaphragms etc. inside closed cross-section materials in “Steel Construction Technical Guidelines-Factory Building: Architectural Institute of Japan” In the figure, (a) is a front view and (b) is an enlarged AA cross-sectional view of (a). It is the figure which showed simply the structure of the beam-column joint core of the through diaphragm type shown by FIG. 3, (A) is a top view, (B) is a longitudinal cross-sectional view, (C) is a bottom view. 3 shows a case where openings are provided in the pattern shown in FIG. 3 (FIG. 4) in the reinforcing plate of the non-diaphragm column head column beam joint core, where (A) is a plan view and (B) is a plan view. The transcription of FIG. 2 (c) and (d) are the transcription of FIG. 2 (d). FIG. 6 is a perspective view of a rectangular steel pipe column with a column beam joint core in which a square steel pipe column is welded and fixed to a non-diaphragm column head column beam joint core provided with the opening of the conventional pattern of FIG. (However, it is shown in a state where beam flanges are joined in all directions). BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a square steel pipe column with a column head column beam joint core according to an embodiment of the present invention, in which (A) is a plan view, (B) is a front view, and (C) is a BB cross-sectional view. It is a perspective view of a square steel pipe column in the column head column beam joint core of FIG. In this invention, the arrangement | positioning point of the some circular hole provided in a reinforcement board is demonstrated, (A) is the case of the center pillar which joined the beam to four directions (same as (A) of FIG. 7), (B) is three. In the case of a side column with beams connected in the direction, (c) is a corner column with beams connected in two directions at right angles, (d) is another example of a corner column, and (e) is a corner column. Still another example, (f) shows the case of a side column with beams joined to the left and right. In order to know the situation where the horizontal force acting from the beam flange is transmitted through the reinforcing plate, it is a diagram showing the flow of force obtained by simplifying the reinforcing plate and the beam flange into a single plate and performing FEM analysis. Yes, (b) is the case of the reinforcing plate without holes, (b) is the case of the reinforcing plate with five holes having a large hole in the center, and (c) is the case of the reinforcing plate with four holes of the embodiment of the present invention. is there. Regarding the thickness of the reinforcing plate of the column head column beam joint core in the present invention, the column head column beam joint core is a reinforcing plate that can ensure the same proof stress as when the column is joined to the upper floor. It is a figure explaining simply the FEM analysis performed in order to obtain | require plate | board thickness t ', (A) is a mesh figure of the column beam junction core modeled for FEM analysis, (B) shows an analysis result. It is a graph. In the flat plate simulating the column head, in the case of no hole, in the case of four holes (corresponding to the reinforcing plate of the present invention), in the case of five holes (corresponding to the conventional reinforcing plate), It is a graph which shows the result of having investigated the relationship between displacement (delta) mm, a load, and P (kN) by FEM analysis.

  Hereinafter, a square steel pipe column with a column head column beam joint part core of the present invention and a form for carrying out the manufacturing method will be described with reference to the drawings.

7 and 8 show an embodiment of a square steel pipe column 16 with a column head column beam joint core according to an embodiment of the present invention. 7 is a plan view of a square steel pipe column 16 with a column head column beam joint core, (B) is a front view of (A), (C) is a cross-sectional view along BB of (A), and FIG. 8 is a column head column. It is a square steel pipe pillar 16 perspective view with a beam junction part core.
This column head column beam joint core-attached square steel pipe column 16 is a case of a middle column, and a column beam joint core 12 for a column head of a non-diaphragm type column head is welded and fixed to the upper end of a square square steel tube column 3; A short beam bracket 4 made of H-shaped steel having the same size as the H-shaped steel beam is welded and fixed to the four surfaces.
The column beam joint core 12 has a structure in which a square reinforcing plate 15 is welded to an upper end surface of a core material 12a which is a short thick-walled square steel pipe having an aspect ratio of 1: 1 in plan view. 15 is provided with circular holes 15b in the vicinity of the inner peripheral corners of the core material 12a for air venting or air supply when performing hot dip galvanization. The total area of the four circular holes 15b is 1 / of the inner horizontal horizontal cross-sectional area of the core material 12a (the area surrounded by the inner contour of the core material cross section) in accordance with the recommendation of the Architectural Institute of Japan / steel construction technical guidelines. 3 or more.
It should be noted that the four circular holes 15b have the same size and size with respect to the two center lines S ₁ and S ₂ orthogonal to each other that pass through the center of the reinforcing plate 15 and are parallel to the sides of the reinforcing plate 15 in FIG. The positions are arranged symmetrically. Therefore, the intermediate line (S ₁ ) between the bonding positions of the left and right beams 4 in the figure is also symmetric with respect to the intermediate line (S ₂ ) between the bonding positions of the upper and lower beams 4 in the figure.

The size of the rectangular steel pipe column 3 of the embodiment is 300 width × 300 width × 19 mm thickness. The thickness of the core material 12a is 29 mm, that is, the size is 300 width × 300 width × 29 mm thickness. In the case of a non-diaphragm type column beam joint core, a thick-walled square steel pipe whose thickness is 4 mm or more thicker than that of a square steel pipe column is generally used, but in this embodiment, the thickness is further increased. ing. The thickness of the reinforcing plate 15 is 22 mm. Therefore, the inner diameter (internal dimension) of the core material 12a is 300−29 × 2 = 242 mm, and the empty horizontal sectional area in the core material is 242 mm × 242 mm = 58564 mm ² .
The diameter of the circular hole 15b provided in the reinforcing plate 15 is, for example, 80 mm. In this case, the area of the circular hole 15b is the total area of 5024mm ^2, 4 two circular holes 15b is 20096mm ^2. Therefore, the ratio of the entire area of the opening to the horizontal horizontal cross-sectional area in the core material is 200016/58564 = 0.34, which is larger than 1/3.
Moreover, the size of the beam bracket 4 which is a short H-shaped steel beam is 400 * 200, for example. In FIG. 6 and FIG. 8, two beams in one direction out of two orthogonal directions are illustrated as low beams.

The square steel pipe column 16 with the column head column beam joint core is manufactured as follows, for example.
As shown in FIG. 7 (a), four circular holes 15b are formed in a square reinforcing plate that is slightly smaller in size than the cross-sectional area (outer contour cross-sectional area) of the core material. The opening position is a position near the inner peripheral corner of the core material 12a. The inner periphery of the core material 12a is indicated by a broken line 12a ′ in FIG.
The column beam joint core 12 is configured by welding and fixing the reinforcing plate 15 having the four circular holes 15b to the end surface (upper end surface) on the upper side of the core material 12a. Moreover, the beam bracket 4 which is a short H-section steel is welded and fixed to the four side wall surfaces of the core material 12a. Moreover, the upper end surface of the square steel pipe column 3 is welded and fixed to the end surface (lower end surface) on the lower side of the core material 12a. In each figure, the beam bracket 4 is provided with a plurality of bolt holes for bolting via a beam body and a joint plate, but this is omitted in each figure.
Next, hot dip galvanization is performed. In that case, the square steel pipe column 16 with the column head column beam joint core is placed in the plating tank with an inclination in which the upper end side of the column beam joint core 12, that is, the reinforcing plate 15 side is the upper side, and the lower end of the square steel pipe column 3 is the lower side. Immerse.

In this case, in a state where the square steel pipe column 3 is welded and fixed to the lower end surface of the column beam joint core 12 in which the reinforcing plate 15 having the opening 15b is welded and fixed to the upper end surface, that is, the square steel pipe with the column head column beam joint core. Since the hot dip galvanization is performed in the state of the pillars 16, good hot dip galvanization can be performed with good workability.
That is, when placed in a hot dip galvanizing tank in an inclined state with the reinforcing plate 15 side (column beam joint core 12 side) on the upper side and the lower end of the square steel pipe column 3 on the lower side, the lower side is a long rectangular steel pipe column. On the other hand, since the opening 15b of the reinforcing plate 15 performs the air venting action, zinc is smoothly penetrated into the pipe and filled. Moreover, when it lifts from a plating tank in the same inclination state, the opening part 15b of the reinforcement board 15 carries out the air supply effect | action to a pipe | tube, and zinc in a pipe | tube pulls out from the lower end opening of a steel pipe vigorously, Therefore Work efficiency improves. At the same time, zinc does not collect at the lower end of the square steel pipe column 3 which is a simple cylinder.
Furthermore, since air flows in and out smoothly from the opening of the reinforcing plate, it is possible to prevent the occurrence of plating cracks in the square steel pipe column.
The four circular holes 15b provided in the reinforcing plate 15 pass through the center of the reinforcing plate 15 and are parallel to the two center lines S ₁ and S ₂ that are orthogonal to each other (center line S _1). And the center line S ₂ ) are symmetric in size and position, and therefore the intermediate line (S ₁ ) between the joint positions of the left and right beams 4 in FIG. ) Is also symmetric with respect to the intermediate line (S ₂ ) between the joint positions of the upper and lower beams 4, so that the stress applied to the reinforcing plate 15 by the load from the beams 4 is less likely to be obtained, which is favorable in securing the proof stress. . Moreover, it can be said that it is preferable for uniformly attaching zinc when it is immersed in a plating tank and hot dip galvanized.

Moreover, since the opening provided in the reinforcing plate 15 is formed as a circular hole 15b in the vicinity of the four inner peripheral corners of the core material 12a and there is no hole in the central portion, the fillet welded portion around the reinforcing plate Can be transmitted through the central part of the reinforcing plate.
FIG. 10 is obtained by performing FEM analysis by simplifying the reinforcing plate and the beam flange into a single plate as shown in the figure in order to know the situation where the horizontal force acting from the beam flange is transmitted through the reinforcing plate. (B) is a five-hole reinforcing plate 5 having a large hole at the center and four small holes near the corners. (C) is an embodiment of the present invention, which is the case of the reinforcing plate 15 having no holes in the center and four holes in the corners.
As shown in the figure, the reinforcing plate 5 ′ without holes in (A) can transmit the stress generated by the horizontal force acting from the beam as it is, and the reinforcing plate 5 with a large hole in the center of (B) is at the center. The stress generated by the horizontal force acting from the beam due to the presence of a large hole in the portion cannot be sufficiently transmitted. The reinforcing plate 15 having no hole in the central portion of (c) can transmit the stress at the central portion of the reinforcing plate. It can be seen that the stress generated by the horizontal force acting from can be transmitted well.

As described above, in the reinforcing plate 15 having no hole in the central portion, the stress transmitted from the fillet weld around the reinforcing plate can be transmitted through the central portion of the reinforcing plate. Even with an opening having a large total area of 3 or more, the load that the reinforcing plate 15 can bear against the horizontal force acting from the beam flange is much lower than when a large circular hole is provided in the central portion of the reinforcing plate. Therefore, even if the plate thickness is not extremely increased, it is possible to cause the reinforcing plate 15 to bear a load equivalent to the load of the upper floor column in the middle portion of the column. This ensures the proof stress required for non-diaphragm column head column beam joints even if the reinforcing plate is provided with an extremely wide opening having a total area of 1/3 or more of the hollow horizontal sectional area in the core material. Is possible.
The result confirmed by conducting detailed analysis by FEM (finite element method) will be described below.
According to an academic paper based on experiments, if the plate thickness of the reinforcing plate is 12 mm for a thick square steel pipe (core material) of □ 300 × 300 × 29 as a column beam joint core for a column head, It is said that it has the same proof strength as the case where the column is joined to the upper floor ("Takataka et al .: Experimental study on the mechanical performance of the non-diaphragm type column beam joint using thick square steel pipe part 1 -2, Summary of Academic Lectures of the Architectural Institute of Japan, P1089-1091, 2011.8 ").
With reference to this experimental study, FEM analysis was performed on a □ 300 × 300 × 29 thick square steel pipe to which a reinforcing plate having an opening (circular hole 15b) as shown in FIG. went. However, in actual FEM analysis, the beam to be joined to the thick-walled square steel pipe is not the H-shaped steel beam itself, but flat beams (corresponding to the upper flange of the H-shaped steel beam) as shown in FIG. The structure was joined to a thick square steel pipe.
The analysis result is as shown in the graph of FIG. 11 (b). In the case of a reinforcing plate having a thickness of 12 mm, the proof stress Py = 1484 kN when no opening is provided (thick solid line: no PL-12 hole). When the opening of 1/3 of the horizontal horizontal sectional area in the steel pipe is provided in the pattern of FIG. 7 (a) (thin broken line: with PL-12 hole), the proof stress Py is 1276 kN, which is reduced by about 14%. Yes.
On the other hand, when the plate thickness of the reinforcing plate is 22 mm and the openings are provided in the same pattern as in FIG. 7 (a) (thick broken line: with PL-22 hole), the proof stress Py is 1423 kN, and the reinforcing plate has a thickness of 12 mm. It was almost equivalent to the yield strength (1484 kN) when no opening was provided for the plate.
By the same FEM analysis as described above, for a plurality of sizes of thick-walled square steel pipes, it is possible to ensure the same proof stress as when the column beam joint core having the reinforcing plate not provided with the opening is joined to the upper floor. With respect to the thickness t of the reinforcing plate (this t is referred to as the standard plate thickness), the column beam joint core having the reinforcing plate provided with the opening has a proof strength equivalent to the case where the column is joined to the upper floor. The thickness t ′ of the reinforcing plate necessary for ensuring was obtained. The analysis results are shown in Table 1.

As shown in Table 1, the combinations of the tube diameter Dmm and the plate thickness Tmm of the thick square steel pipe (core material) subjected to FEM analysis are “D150, T16.5”, “D175, T17”, “D200, T22”, There are five sizes, “D250, T24” and “D300, T29”.
For each of these sizes, in the case of a reinforcing plate that does not have an opening, if the plate thickness t (standard plate thickness t) is 6 mm, 6 mm, 9 mm, 9 mm, and 12 mm, respectively, the pillar is joined to the upper floor. In the case of a reinforcing plate having an proof strength equivalent to that of the case where an opening is provided, if the plate thickness t ′ is 12 mm, 12 mm, 16 mm, 16 mm, and 22 mm, respectively, the column is joined to the upper floor The analysis results show that it has the same proof stress.
Therefore, the ratio t ′ / D between the minimum required plate thickness t ′ and the thick square steel pipe diameter D when the reinforcing plate is provided with openings is 12/150 (= 8.0%), 12 / 175 (= 6.9%), 16/200 (= 8.0%), 16/250 (= 6.4%), 22/300 (= 7.3%).
From this result, even if the reinforcing plate is provided with a wide opening of 1/3 of the cross-sectional area of the closed cross section (empty horizontal cross-sectional area in the core material), the thickness t ′ of the reinforcing plate and the thick square steel pipe diameter D If the ratio t ′ / D is 8% or more (t ′ / D ≧ 8%), the column beam joint core for the column head having the reinforcing plate is the case where the column is joined to the upper floor. It can be said that it has equivalent proof stress.
The above FEM analysis results were analyzed for the case of the side column where the beams are joined to the left and right as described above, but the reinforcing plate has the standard plate thickness t without holes and the plate thickness t ′ with holes. Therefore, even in the case of the middle column in which the beams are joined in four directions, the comparison between the case where the reinforcing plate is the standard plate thickness t without holes and the plate thickness t ′ with holes is the same. It can be said. Although the details are omitted, the same applies to a corner column in which beams are joined in three directions.

FIG. 12 shows three types of flat plates simulating the column heads: no holes, four holes (corresponding to the reinforcing plate of the present invention), and five holes (corresponding to the conventional reinforcing plate). The result of investigating the relationship between displacement δmm, load and P (kN) by FEM analysis for the pattern is shown.
As shown in the figure, it is natural that the case without holes (solid line) can withstand a large load, but the case with four holes (dashed line) is compared with the case with five holes (one-dot chain line). It can be seen that it can withstand larger loads.

FIG. 9 shows various patterns of arrangement of the circular holes 15b provided in the reinforcing plate 15 as openings.
(A) is the case of the middle column in which the beams (beam brackets) 4 are joined to the four sides of the square steel pipe column 3, which are those of FIGS. 7 and 8 described above.
(B) is a case of a side column in which a beam 4 is joined to three sides of a square steel pipe column 3 on both the left and right sides and a plane perpendicular thereto, and four circular holes 15b provided in the reinforcing plate 15 are shown. Is the size of the two center lines S ₁ and S ₂ that pass through the center of the reinforcing plate 15 and are parallel to the sides of the reinforcing plate 15 (both with respect to the center line S _{1 and with} respect to the center line S ₂ ). And the position is symmetrical.
(C), (d), (e) are corner columns in which the beam 4 is joined to two mutually perpendicular surfaces of the square steel pipe column 3, and the bisector direction of the angle formed by the two beams 4 The size and position of the reinforcing plate diagonal S are symmetric.
The (c) has two circular holes 15b in the vicinity of the inner peripheral corner in the direction orthogonal to the reinforcing plate diagonal S, and two circular holes 15b in the vicinity of the inner peripheral corner on the reinforcing plate diagonal S. , Symmetric with respect to the reinforcing plate diagonal S.
The (d) includes two circular holes 15b in the vicinity of the inner peripheral corner in the direction orthogonal to the reinforcing plate diagonal S, and one large circular hole 15b in the vicinity of the outer inner peripheral corner on the reinforcing plate diagonal S. However, it is symmetrical with respect to the reinforcing plate diagonal S. The three circular holes may have the same size, and the total area may be the same as described above.
The (e) includes two circular holes 15b in the vicinity of the inner peripheral corner in the direction orthogonal to the reinforcing plate diagonal S, and one large circular hole 15b in the vicinity of the inner peripheral corner on the reinforcing plate diagonal S. However, it is symmetrical with respect to the reinforcing plate diagonal S.
(F) is a case where the beams 4 are joined only to the left and right sides of the square steel pipe column 3, and the four circular holes 15 b provided in the reinforcing plate 15 pass through the center of the reinforcing plate 15. The two center lines S ₁ and S ₂ that are orthogonal to each other and parallel to the fifteen sides are symmetrical in size and position.
In addition to the above, various patterns can be adopted as the pattern in which the plurality of circular holes are arranged symmetrically with respect to the symmetry axis S.

3 Square steel pipe pillar (lower floor pillar),
3'upper column 4 beam bracket (H-shaped steel beam)
4a Upper flange 4b Lower flange 12 Column-beam joint core 12a (of non-diaphragm type) Core material 12a 'Inner circumference 15 of core material Reinforcing plate 15b Circular hole (opening)
16 Column head column beam jointed square steel pipe column with core S ₁ , S _{2 Two} centerlines that pass through the center of the reinforcing plate and are parallel to the side of the reinforcing plate S Two bisectors of the angle formed by the two beams Reinforcement plate diagonal

Claims (7)

A square steel pipe column with a column head column beam joint core provided with a non-diaphragm type column beam joint core at the column head of the square steel tube column,
The column beam joint core has a structure in which a square reinforcing plate is welded to the upper end surface of a core material that is a short thick square steel pipe having an aspect ratio of 1: 1 in a plan view. An opening consisting of a circular hole is provided only in the vicinity of the inner peripheral corner of the core material,
With a column head column beam joint core characterized in that it is immersed in a hot dip galvanizing bath in a state where the upper end surface of the rectangular steel pipe column is welded to the lower end surface of the column beam joint core. Square steel pipe column.   The circular holes provided in the reinforcing plate are respectively provided in the vicinity of the four inner peripheral corners of the core material, and the total area of each circular hole is 1/3 or more of the empty horizontal cross-sectional area in the core material. The square steel pipe column with a column head column beam joint core according to claim 1.   When at least two beams joined to the left and right pipe wall surfaces of the square steel pipe column are provided, the circular hole provided in the reinforcing plate passes through the center of the reinforcing plate and is perpendicular to each other and parallel to the side of the reinforcing plate. The square steel pipe column with a column head column beam joint core according to claim 1 or 2, characterized in that the size and position are symmetrical with respect to the center line.  In the case of having only two beams that are respectively joined to the mutually perpendicular wall surfaces of the square steel pipe column, the circular hole provided in the reinforcing plate is related to the reinforcing plate diagonal in the bisector direction of the angle formed by the two beams. The square steel pipe column with a column head column beam joint core according to claim 1, wherein the size and the position are symmetrical.  The square steel pipe column with a column head column beam joint core according to any one of claims 1 to 3, wherein the reinforcing plate has a plate thickness of 8% or more of the outer diameter of the core material.   The column head column beam connection according to any one of claims 1 to 4, wherein the core material is thicker by 4 mm or more than the plate thickness of the lower rectangular steel pipe column bonded to the lower end surface. Square steel pipe column with a core. A square steel pipe with a column head column beam joint core for producing a square steel pipe column with a non-diaphragm type column beam joint core at the column head of a square steel pipe column and galvanized column head column beam joint core. A method of manufacturing a pillar,
In the square steel plate, a reinforcing plate having a plurality of circular holes is formed by opening a circular hole so as to be attached near the inner peripheral corner of the core material,
The reinforcing plate is welded to the upper end surface of the core material which is a short thick-walled square steel pipe having an aspect ratio of 1: 1 in plan view to constitute the column beam joint core,
Welding the upper end surface of the rectangular steel pipe column to the lower end surface of the column beam joint core;
The integral beam-column joint core and rectangular steel pipe column are immersed in a hot dip galvanizing bath in an inclined state with the reinforcing plate side on the upper side and the lower end of the rectangular steel tube column on the lower side, and are pulled up from the hot dip galvanizing bath in the same inclined state. A method of manufacturing a square steel pipe column with a column head column beam joint core characterized by subjecting to hot dip galvanizing.

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