JP7650176B2 - Column-beam joint core - Google Patents

Description

The present invention relates to a column-beam joint core.

A conventional beam-column joint core is a non-diaphragm construction core that uses a steel pipe with a rectangular cross section at the joint, as shown in Patent Document 1. The beam-column joint core includes a steel pipe that connects the upper steel pipe on the upper side and the lower steel pipe on the lower side, and has four side walls that form the four sides of the rectangular cross section. The thickness of the steel pipe is set to be larger than the thicknesses of the upper steel pipe and the lower steel pipe.

Japanese Patent Application Publication No. 8-302899

The ultimate strength of a non-diaphragm beam-column joint structure is determined by the smaller of the out-of-plane full plastic strength and root penetration fracture strength of the thick steel pipe at the connection. The out-of-plane full plastic strength increases as the plate thickness of the steel pipe at the connection increases. On the other hand, if the plate thickness of the steel pipe at the connection becomes too thick, the stress is not transmitted to the entire plate thickness, and the improvement in root penetration fracture strength due to the increase in plate thickness may be small.

On the other hand, the out-of-plane yield strength and out-of-plane full plastic strength increase with an increase in the thickness of the steel pipe at the connection, so the larger the beam to which it is attached, the more the plate thickness must be increased. From the perspective of improving the root penetration fracture strength, reinforcement other than increasing the plate thickness is desirable, but from the perspective of improving the out-of-plane yield strength and out-of-plane full plastic strength, it is efficient to increase the plate thickness to improve the strength, so the solutions from each perspective are contradictory.

The present invention was made to solve these problems, and aims to provide a column-beam joint core that can improve the strength of a column-beam joint structure while suppressing an increase in cross-sectional area and facilitating manufacturing.

The column-beam joint core of the present invention is a column-beam joint core of the non-diaphragm construction method using a joint steel pipe with a square cross section at the joint, and is equipped with a joint steel pipe that connects the upper upper steel pipe and the lower lower steel pipe to each other and has four side walls that form the four sides of the square cross section, and inside the joint steel pipe are four steel plates that are fixed to all combinations of adjacent pairs of side walls, and each steel plate is fixed with one end inclined to one side wall and the other end inclined to the other side wall when viewed from the top-bottom direction, and adjacent steel plates are fixed to the same side wall via the same weld.

Inside the joint steel pipe, four steel plates are provided that are fixed to all combinations of pairs of adjacent side walls. When viewed from the top and bottom, each steel plate is fixed with one end inclined to one side wall and the other end inclined to the other side wall. Therefore, each steel plate can reinforce the four side walls of the joint steel pipe from the inside. When such steel plates are provided, the strength can be improved efficiently compared to when the plate thickness of the joint steel pipe is simply increased. Therefore, the strength can be improved while suppressing the increase in the plate thickness of the joint steel pipe. In addition, adjacent steel plates are fixed to the same side wall via the same weld. This configuration can reduce the number of welds compared to when adjacent steel plates are fixed to the same side wall via separate welds. Therefore, it is easy to manufacture. As a result, it is possible to improve the strength while suppressing the increase in cross-sectional area and facilitating manufacture.

The steel plate may be attached to the entire length of the steel pipe at the connection in the axial direction of the steel pipe. In this case, the effect of improving the strength can be obtained over the entire length of the steel pipe at the connection.

The steel plate may be attached to a portion of the steel pipe at the connection in the axial direction of the steel pipe. In this case, the effect of improving the strength can be obtained by limiting it to the particularly necessary parts of the steel pipe at the connection.

The steel pipe at the connection section is made up of two channel steel pieces, and two of the welds that secure the four steel plates can also serve as welds for the channel steel pieces. In this case, the number of welds in the entire column-beam connection core can be reduced.

The steel pipe at the connection section is made up of four angle irons, and the four welds that secure the four steel plates can also serve as the welds for the angle irons. In this case, the number of welds in the entire column-beam connection core can be reduced.

The present invention makes it possible to improve the strength of a column-beam joint structure while suppressing an increase in cross-sectional area and facilitating manufacturing.

FIG. 1(a) is a side view showing a column-beam joint core according to an embodiment of the present invention, and FIG. 1(b) is a view from above of the steel pipe at the joint portion of the column-beam joint core shown in FIG. 1(a). FIG. 11 is a side view showing a column-beam joint core according to a modified example. FIG. 13 is a diagram showing an example of manufacturing a steel pipe for a joint portion. FIG. 13 is a diagram showing an example in which the welded portion of the steel pipe at the connection section and the welded portion of the steel plate are shared. FIG. 1 is a diagram illustrating a test specimen for analysis. FIG. 1 is a diagram showing an analysis model and analysis results.

A preferred embodiment of the present invention will be described below with reference to the drawings.

Figure 1(a) is a side view showing a column-beam joint core 200 according to an embodiment of the present invention. Figure 1(b) is a top view of the joint steel pipe of the column-beam joint core 200 shown in Figure 1(a). As shown in Figure 1(a), the column-beam joint structure 100 includes a column 1 and beams 2A and 2B joined to the column 1. The beams 2A and 2B are joined to the column 1 at a joint 3. The beams 2A and 2B have an H-shaped cross section and include upper and lower flanges 2a and 2b, and a web portion 2c that connects the flanges 2a and 2b together.

In this embodiment, a column-beam joint core 200 including a joint steel pipe 10 having a rectangular cross section made of steel is used for the joint 3. The joint steel pipe 10 connects the upper steel pipe 4 on the upper side and the lower steel pipe 6 on the lower side. Here, no diaphragm, which is a partition wall that spreads horizontally inside the column 1, is provided in the connection between the upper steel pipe 4 and the joint steel pipe 10, the connection between the lower steel pipe 6 and the joint steel pipe 10, or inside the joint steel pipe 10. In this way, the column-beam joint core 200 is configured as a column-beam joint core for a non-diaphragm construction method using the joint steel pipe 10.

As shown in FIG. 1(b), the joint steel pipe 10 has four side walls 11A, 11B, 11C, and 11D that constitute the four sides of the rectangular cross section. The side walls 11A and 11C face each other while being spaced apart so as to be parallel to each other. The side walls 11B and 11D are perpendicular to the side walls 11A and 11C and face each other while being spaced apart so as to be parallel to each other. The side walls 11A and 11B are arranged adjacent to each other and are connected to each other at the corners 12A. The side walls 11B and 11C are arranged adjacent to each other and are connected to each other at the corners 12B. The side walls 11C and 11D are arranged adjacent to each other and are connected to each other at the corners 12C. The side walls 11D and 11A are arranged adjacent to each other and are connected to each other at the corners 12D. The corners 12A, 12B, 12C, and 12D of the joint steel pipe 10 are rounded with a predetermined curvature. The size of the joint steel pipe 10 is not particularly limited, but may be set in the range of 150 mm to 1000 m on a side.

The manufacturing method for the joint steel pipe 10 is not particularly limited. For example, as shown in FIG. 3(a), the joint steel pipe 10 may be formed by forming a rolled material into a square shape. In this case, the ends of the rolled material are fixed together at a welded portion 24. Alternatively, as shown in FIG. 3(b), (c), (d), and (e), the joint steel pipe 10 may be formed by fixing the ends of multiple box-shaped members together at a welded portion 24.

Four steel plates 13A, 13B, 13C, 13D are provided inside the joint steel pipe 10, which are fixed to all combinations of pairs of adjacent side walls. The joint steel pipe 10 is provided with a steel plate 13A that is fixed to a pair of adjacent side walls 11A, 11B. The joint steel pipe 10 is provided with a steel plate 13B that is fixed to a pair of adjacent side walls 11B, 11C. The joint steel pipe 10 is provided with a steel plate 13C that is fixed to a pair of adjacent side walls 11C, 11D. The joint steel pipe 10 is provided with a steel plate 13D that is fixed to a pair of adjacent side walls 11D, 11A.

When viewed from the top-bottom direction, the steel plate 13 is fixed with one end inclined to one side wall portion 11, and the other end inclined to the other side wall portion 11. Specifically, when viewed from the top-bottom direction, the steel plate 13A is fixed with one end 13Aa inclined to one side wall portion 11A, and the other end 13Ab inclined to the other side wall portion 11B. In FIG. 8B, when viewed from the top-bottom direction, one end 13Ba is fixed inclined to one side wall portion 11B, and the other end 13Bb is fixed inclined to the other side wall portion 11C. When viewed from the top-bottom direction, the steel plate 13C is fixed with one end 13Ca inclined to one side wall portion 11C, and the other end 13Cb is fixed inclined to the other side wall portion 11D. When viewed from the top and bottom, one end 13Da of the steel plate 13D is fixed at an incline to one side wall portion 11D, and the other end 13Db is fixed at an incline to the other side wall portion 11A.

In this embodiment, the end 13Aa of the steel plate 13A and the end 13Db of the steel plate 13D are fixed to the center of the side wall 11A by welding. Therefore, the end 13Aa of the steel plate 13A and the end 13Db of the steel plate 13D are fixed to the side wall 11A via the same weld 14A. The end 13Ba of the steel plate 13B and the end 13Ab of the steel plate 13A are fixed to the center of the side wall 11B by welding. Therefore, the end 13Ba of the steel plate 13B and the end 13Ab of the steel plate 13A are fixed to the side wall 11B via the same weld 14B. The end 13Ca of the steel plate 13C and the end 13Bb of the steel plate 13B are fixed to the center of the side wall 11C by welding. Therefore, the end 13Ca of the steel plate 13C and the end 13Bb of the steel plate 13B are fixed to the side wall portion 11C via the same welded portion 14C. The end 13Da of the steel plate 13D and the end 13Cb of the steel plate 13C are fixed to the center position of the side wall portion 11C by welding. Therefore, the end 13Ca of the steel plate 13C and the end 13Db of the steel plate 13D are fixed to the side wall portion 11D via the same welded portion 14D.

The ends of the four steel plates 13 adjacent to each other are fixed together by a single weld 14. Before being welded, the four steel plates 13 are constructed as separate plate materials. In other words, this embodiment is different from, for example, inserting a small steel pipe with a square cross section into the joint steel pipe 10 before welding, and welding the corners of the small steel pipe to the inner surface of the joint steel pipe 10.

Here, the plate thickness tn of the joint steel pipe 10 is thicker than the plate thickness tc of the upper steel pipe 4 and the lower steel pipe 6. The plate thickness tn of the joint steel pipe 10 is the plate thickness of the side wall parts 11A, 11B, 11C, and 11D. Although not particularly limited, the plate thickness tn is set to 15 mm or more, preferably 25 mm or more, and 100 mm or less, preferably 55 mm or less. The plate thickness tc of the upper steel pipe 4 and the lower steel pipe 6 is the plate thickness of the four side wall parts of the upper steel pipe 4 and the lower steel pipe 6. Although not particularly limited, the plate thickness tc is set to 6 mm or more, preferably 9 mm or more, and 60 mm or less, preferably 40 mm or less, in the range of "plate thickness tn>plate thickness tc". The plate thickness td of the steel plates 13A, 13B, 13C, and 13D is thinner than the plate thickness tn of the joint steel pipe 10. Although not particularly limited, the plate thickness td is set to 6 mm or more, preferably 9 mm or more, and 40 mm or less, preferably 28 mm or less, in the range of "plate thickness tn>plate thickness td".

In this embodiment, the angle θ of one end of the steel plate 13 relative to one side wall portion 11, and the angle θ of the other end of the steel plate 13 relative to the other side wall portion 11 are 45°. Specifically, the angle θ of one end 13Aa of the steel plate 13A relative to one side wall portion 11A, and the angle θ of the other end 13Ab of the steel plate 13 relative to the other side wall portion 11B are 45°. The angle θ of one end 13Ba of the steel plate 13B relative to one side wall portion 11B, and the angle θ of the other end 13Bb of the steel plate 13 relative to the other side wall portion 11C are 45°. The angle θ of one end 13Ca of the steel plate 13C relative to one side wall portion 11C, and the angle θ of the other end 13Cb of the steel plate 13C relative to the other side wall portion 11D are 45°. The angle θ of one end 13Da of the steel plate 13D relative to one side wall portion 11D, and the angle θ of the other end 13Db of the steel plate 13D relative to the other side wall portion 11A are 45°.

However, the angle θ is not necessarily limited to 45°, and may be changed as appropriate depending on the attachment direction and number of beams 2. For example, the angle θ may be set to 30° or more, or 60° or less.

A gap 16 is formed between the corner 12 of the connection steel pipe 10 and the steel plate 13. Specifically, a gap 16A is formed between the corner 12A of the connection steel pipe 10 and the steel plate 13A. A gap 16B is formed between the corner 12B of the connection steel pipe 10 and the steel plate 13B. A gap 16C is formed between the corner 12C of the connection steel pipe 10 and the steel plate 13C. A gap 16D is formed between the corner 12D of the connection steel pipe 10 and the steel plate 13D.

The distance Ld between the outer surface of the joint steel pipe 10 and the weld 14, which is the fixed position of the steel plate 13 across the gap 16, is at least twice the plate thickness tn of the joint steel pipe 10. As shown in FIG. 1(b), the distance Ld of the weld 14B from the outer surface of the side wall 11A is defined by the distance between the outer surface and the weld 14B of the steel plate 13A across the gap 16A. This distance is the distance in the vertical direction to the outer surface of the side wall 11A. The distance Ld of the weld 14D from the outer surface of the side wall 11A is defined by the distance between the outer surface and the weld 14D of the steel plate 13D across the gap 16D. The distance Ld of the welds 14A, 14C from the outer surface of the side wall 11B is defined by the distance between the outer surface and the welds 14A, 14C of the steel plates 13A, 13B across the gaps 16A, 16B. The distance Ld of the welds 14B, 14D from the outer surface of the side wall 11C is defined by the distance between the outer surface and the welds 14B, 14D of the steel plates 13B, 13C across the gaps 16B, 16C. The distance Ld of the welds 14C, 14A from the outer surface of the side wall 11D is defined by the distance between the outer surface and the welds 14C, 14A of the steel plates 13C, 13D across the gaps 16C, 16D. In this embodiment, each weld 14A, 14B, 14C, and 14D is provided at the center of each side wall 11A, 11B, 11C, and 11D. Therefore, the distance Ld is approximately half the dimension of one side of the joint steel pipe 10.

As shown in FIG. 1(a), the steel plates 13A, 13B, 13C, and 13D are attached to the steel pipe 10 at the connection section over the entire length in the axial direction of the steel pipe. In other words, the steel plates 13A, 13B, 13C, and 13D extend in the axial direction of the steel pipe (up and down direction) from the upper end 10a to the lower end 10b of the steel pipe 10 at the connection section.

Alternatively, as shown in FIG. 2, the steel plates 13A, 13B, 13C, and 13D may be attached to a portion of the joint steel pipe 10 in the axial direction of the steel pipe. Specifically, the joint steel pipe 10 has a first region E1 where the steel plates 13A, 13B, 13C, and 13D are provided on the upper end 10a side, a second region E2 where the steel plates 13A, 13B, 13C, and 13D are provided on the lower end 10b side, and a third region E3 where the steel plates 13A, 13B, 13C, and 13D are not provided at a midpoint in the axial direction of the steel pipe. The first region E1 extends from the upper end 10a to below the upper flange 2a of the beams 2A and 2B. The second region E2 extends from the lower end 10b to above the lower flange 2b of the beams 2A and 2B.

Here, as shown in FIG. 4(a), when the joint steel pipe 10 is composed of two channel steels, the welds with the steel plate 13 may be shared. Specifically, the two channel steels 31A, 31B have a U-shaped cross-sectional shape. Then, the ends of the two channel steels 31A, 31B are joined so as to face each other, and the welds 24A, 24B are formed to fix them to each other. At this time, the welds 24A, 24B have an outer surface weld 24a and an inner surface weld 24b. In contrast, two of the welds 14A, 14B, 14C, 14D that fix the four steel plates 13A, 13B, 13C, 13D also serve as the welds 24A, 24B of the channel steels 31A, 31B. Specifically, the inner welds 24b of the two welds 24A and 24B also serve as welds 14B and 14D, respectively. That is, the inner welds 24b of welds 24A are formed at the same time that the welds 14B that secure the steel plates 13A and 13B are formed. Also, the inner welds 24b of welds 24B are formed at the same time that the welds 14D that secure the steel plates 13C and 13D are formed.

As shown in Fig. 4(b), when the joint steel pipe 10 is constructed of four angle irons, the welds with the steel plate 13 may be shared. Specifically, the four angle irons 32A, 32B, 32C, 32D have an L-shaped cross section. Then, adjacent ends of the angle irons 32A, 32B, 32C, 32D are joined facing each other, and the welds 24A, 24B, 24C, 24D are formed to fix them to each other. In contrast, the four welds 14A, 14B, 14C, 14D that fix the four steel plates 13A, 13B, 13C, 13D also serve as the welds 24A, 24B, 24C, 24D of the angle irons 32A, 32B, 32C, 32D. That is, weld 24A is formed at the same time that weld 14A is formed to secure steel plates 13D and 13A together. Weld 24B is formed at the same time that weld 14B is formed to secure steel plates 13A and 13B together. Weld 24C is formed at the same time that weld 14C is formed to secure steel plates 13B and 13C together. Weld 24D is formed at the same time that weld 14D is formed to secure steel plates 13C and 13D together.

Next, we will explain the function and effect of the column-beam joint core 200 according to this embodiment.

First, as an example of a column-beam joint core using the conventional non-diaphragm method, the joint only has a thick-walled steel pipe at the joint, and no steel plate is provided inside. The ultimate strength of a column-beam joint structure using the non-diaphragm method is determined by the smaller of the out-of-plane full plastic strength and the root penetration fracture strength of the thick-walled steel pipe at the joint. The out-of-plane full plastic strength increases as the plate thickness of the steel pipe at the joint increases. On the other hand, if the plate thickness of the steel pipe at the joint becomes too thick, the stress is not transmitted to the entire plate thickness, and the improvement in the root penetration fracture strength due to the increase in plate thickness may be small (structural factor).

On the other hand, the out-of-plane yield strength and out-of-plane full plastic strength increase with an increase in the thickness of the steel pipe at the connection, so the larger the beam to which it is attached, the more the plate thickness must be increased. From the perspective of improving root penetration fracture strength, reinforcement other than increasing the plate thickness is desirable, but from the perspective of improving out-of-plane yield strength and out-of-plane full plastic strength, it is efficient to increase the plate thickness to improve strength, so the solutions from each perspective are contradictory. Thus, with conventional beam-column connection cores, there was a problem that it was difficult to obtain the desired strength by simply increasing the plate thickness of the steel pipe at the connection.

Furthermore, the Building Standards Act stipulates that steel materials with a thickness of over 40 mm must have a reduced design strength (F value). Therefore, when using steel materials with a cross-section that exceeds 40 mm in thickness, the increase in cross-sectional area is not directly reflected in the design strength. However, this does not apply if the Minister of Land, Infrastructure, Transport and Tourism certifies that steel materials with a thickness of 40 mm or more have the same performance as steel materials with a thickness of 40 mm or less. For example, there are many products on the market that are made of H-shaped steel or steel plates rolled using the TMCP process, have obtained the above-mentioned certification, and are sold with no reduction in standard strength. However, the introduction of the TMCP process tends to result in problems such as higher manufacturing costs than conventional rolling methods, and ultimately higher product costs (material factors).

In contrast, in the column-beam joint core 200 according to this embodiment, the plate thickness tn of the joint steel pipe 10 is thicker than the plate thickness tc of the upper steel pipe 4 and the lower steel pipe 6. Therefore, compared to the case where the plate thickness tn of the joint 3 is the same as the plate thickness tc of the upper steel pipe 4 and the lower steel pipe 6, the plate thickness tn of the joint steel pipe 10 is made thicker, thereby improving the bearing strength. In contrast, four steel plates 13 are provided inside the joint steel pipe 10, which are fixed to all combinations of a pair of adjacent side wall portions 11. When viewed from the top and bottom, each steel plate 13 is fixed with one end inclined to one side wall portion 11, and the other end is fixed with an inclined state to the other side wall portion 11. Therefore, each steel plate 13 can reinforce the four side wall portions 11 of the joint steel pipe 10 from the inside. When such a steel plate 13 is provided, the strength can be improved more efficiently than when the plate thickness tn of the steel pipe 10 at the connection section is simply increased.

In the column-beam joint core 200 according to this embodiment, adjacent steel plates 13 are fixed to the same side wall portion 11 via the same welded portion 14. This configuration can reduce the number of welded portions 14 compared to when adjacent steel plates 13 are fixed to the same side wall portion 11 via separate welded portions 14. Specifically, when adjacent steel plates 13 are fixed to the same side wall portion 11 via separate welded portions 14, a total of eight welded portions 14 are formed. In contrast, in this embodiment, the number of welded portions 14 can be reduced to four. This makes it easier to manufacture. As a result, the strength of the column-beam joint structure 100 can be improved while suppressing an increase in cross-sectional area and facilitating manufacture.

The strength of the joint 3 in the non-diaphragm construction method is largely borne by the out-of-plane deformation of the side wall 11 of the joint steel pipe 10, and is not so much borne by the steel plate 13 and the surface adjacent to the side wall 11 that is subjected to out-of-plane deformation by the steel plate 13. In other words, since the steel plate 13 plays an auxiliary role in the out-of-plane deformation of the joint steel pipe 10, even if it is excessively thickened, the effect of improving the strength obtained is low relative to the increase in the total cross-sectional area. Therefore, in order to obtain a high effect of improving the strength while suppressing the increase in the cross-sectional area, the plate thickness td of the steel plate 13 is made thinner than the plate thickness tn of the joint steel pipe 10. As a result, it is possible to improve the strength while suppressing the increase in the cross-sectional area.

In addition, in the column-beam joint core 200 according to this embodiment, there is no need to increase the plate thickness tn of the joint steel pipe 10 more than necessary, so it is possible to keep the plate thickness tn to 40 mm or less while ensuring sufficient strength, which makes it possible to prevent the introduction of the aforementioned TMCP process or the like from increasing product costs. As a result, it becomes possible to solve both the problems of structural factors and material factors mentioned above.

The steel plate 13 may be attached to the entire length of the joint steel pipe 10 in the axial direction of the steel pipe. In this case, the effect of improving the strength can be obtained over the entire length of the joint steel pipe 10.

The steel plate 13 may be attached to a portion of the connection steel pipe 10 in the axial direction of the steel pipe. In this case, the steel plate 13 can be limited to necessary locations of the connection steel pipe 10, particularly the location where the H-shaped steel beam flange is attached, to obtain the effect of improving the strength.

The joint steel pipe 10 is composed of two channel steel pieces, and two of the welds 14 that secure the four steel plates 13 may also serve as the welds 24 of the channel steel 31. In this case, the number of welds in the column-beam joint core 200 as a whole can be reduced. For example, if the two welds 24 of the channel steel 31 and the four welds 14 of the steel plates 13 are formed separately, six welds are formed in the column-beam joint core 200 as a whole. In contrast, the column-beam joint core 200 in Figure 4 (a) can be limited to four welds as a whole.

The joint steel pipe 10 is constructed of four angle irons, and the four welds 14 that secure the four steel plates 13 may also serve as the welds 24 of the angle irons 32. In this case, the number of welds in the column-beam joint core 200 as a whole can be reduced. For example, if the four welds 24 of the angle irons 32 and the four welds 14 of the steel plates 13 are formed separately, eight welds are formed in the column-beam joint core 200 as a whole. In contrast, the column-beam joint core 200 in Figure 4 (b) can be limited to four welds as a whole.

The angle θ of one end of the steel plate 13 relative to one side wall 11, and the angle of the other end of the steel plate 13 relative to the other side wall 11, may be 45°. In this case, the symmetry of the arrangement and shape of each steel plate 13 can be ensured. Therefore, the bearing strength of the four side walls 11 can be improved evenly. In addition, since there is a possibility that the beam 2 will be attached to the joint portion 3 from all four directions, by setting the angle θ to 45°, the joint portion 3 can be made a general-purpose product.

A gap 16 is formed between the corner 12 of the joint steel pipe 10 and the steel plate 13, and the distance Ld between the outer surface of the joint steel pipe 10 and the fixed position of the steel plate 13 across the gap 16 may be at least twice the plate thickness of the joint steel pipe 10. Depending on the shape and manufacturing method of the joint steel pipe 10, welding the steel plate 13 near the corner 12 may reduce workability and structural performance. Therefore, by keeping the distance Ld between the outer surface of the joint steel pipe 10 and the fixed position of the steel plate 13 across the gap 16 at least twice the plate thickness tc of the joint steel pipe 10, the deterioration of workability and structural performance can be suppressed.

Next, the analysis content for confirming the effect of the beam-column joint core 200 according to this embodiment will be described. As shown in Fig. 5(a), in the joint 3 of the non-diaphragm construction method, force is transmitted from the beams 2A, 2B to the column 1 via out-of-plane deformation of the side wall 11 of the joint steel pipe 10. In contrast, as shown in Fig. 5(b), a method is known for verifying the strength due to out-of-plane deformation by a unidirectional tensile test of a test specimen 250 of an element extracted from the flanges 2a of the H-shaped beams 2A, 2B and a part of the joint steel pipe 10 (Abstract of the Architectural Institute of Japan Conference/Nippon Steel & Sumitomo Metal Construction Materials, JFE Steel). In the model shown in Figure 5 (b) simulating the test method, the steel pipe 10 and steel plate 13 at the joint were made of SN490 material, and the load plate 201 simulating the flange 2a of the beam and the welded part between the steel pipe 10 and the load plate 201 were made of TMCP385 material. A finite element analysis was performed, and the "tensile load" of each parameter and the "relative displacement between the load plate and the steel pipe displacement" which means the out-of-plane deformation of the steel pipe wall were compared. The results are shown in Figure 6 (c). In this case, the load plate had a thickness of 40 mm and a width of 200 mm, and the welded part between the load plate 201 and the steel pipe at the joint was a K-shaped groove with a reinforcement height of 10 mm on one side.

As a comparative example, a specimen was prepared in which the steel pipe 10 had a thickness tn of 41 mm and no steel plate 13 was used, as shown in FIG. 6(a). As a test specimen in the example, a specimen was prepared in which the steel pipe 10 had a thickness tn of 35 mm and the steel plate 13 had a thickness td of 9 mm, as shown in FIG. 6(b). As a result of comparing the load-displacement relationship for these test specimens, it is understood that the two have the same load-displacement relationship, as shown in FIG. 6(c). At this time, it is understood that the steel pipes 10 shown in FIG. 6(a) and FIG. 6(b) have the same cross-sectional area, and that even if the side wall portion 11 is thinned, the bearing strength can be ensured by the knee brace of the steel plate 13. In other words, it is understood that by making the non-diaphragm connection with knee brace by the steel plate 13, it is possible to improve the bearing strength of the non-diaphragm construction connection while thinning the side wall portion 11. It can be understood that this solves the problems related to the thickening of the structural and material factors mentioned above. In addition, in Figures 6(a) and (b), dimension lines are provided and numbers are provided for the dimension lines. These numbers indicate the dimensional values, and the unit is "mm." For example, "402" is shown as the dimension of one side of the joint steel pipe 10, which means that one side of the joint steel pipe 10 is "402 mm."

The present invention is not limited to the above-mentioned embodiment and modified examples. The dimensions, angles, etc. described in the above-mentioned embodiment are merely examples and may be modified as appropriate without departing from the spirit of the present invention. In addition, the shapes of the steel pipes and steel plates at the connection section may also be modified as appropriate.

1...column, 2...beam, 3...connection portion, 10...connection portion steel pipe, 11...side wall portion, 13...steel plate, 14...welded portion, 24...welded portion, 31...channel steel, 32...angle steel, 200...column-beam connection core.

Claims (5)

A column-beam joint core using a non-diaphragm construction method using a joint steel pipe having a square cross section at the joint,
The joint steel pipe is connected to an upper steel pipe on the upper side and a lower steel pipe on the lower side, and has four side wall portions that constitute the four sides of the rectangular cross section,
Four steel plates are provided inside the connection steel pipe and are fixed to all combinations of adjacent pairs of the side wall portions,
When viewed from the top-bottom direction, one end of each steel plate is fixed to one of the side wall portions in an inclined state, and the other end of each steel plate is fixed to the other side wall portion in an inclined state,
Adjacent steel plates are fixed to the same side wall portion via the same welded portion ,
A column-beam joint core , wherein the plate thickness of the joint steel pipe is thicker than the plate thicknesses of the upper steel pipe and the lower steel pipe . The column-beam joint core according to claim 1, in which the steel plate is attached to the joint steel pipe over its entire length in the axial direction of the steel pipe. The column-beam joint core according to claim 1, in which the steel plate is attached to a portion of the joint steel pipe in the axial direction of the steel pipe. The column-beam joint core according to any one of claims 1 to 3, in which the joint steel pipe is made of two channel steel pieces, and two of the welds that secure the four steel plates also serve as welds for the channel steel pieces. The column-beam joint core according to any one of claims 1 to 3, wherein the joint steel pipe is composed of four angle irons, and the four welds that fix the four steel plates also serve as welds for the angle irons.

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