Column-beam joint and building equipped therewith

Abstract

To provide a column beam joint part and a building therewith, capable of reducing the steel material amount at the column beam joint part and the welding amount required for manufacturing a panel part of the column beam joint part while securely preventing out-of-plane deformation of a square steel pipe column due to bending moment acting from an end part of a steel beam to the panel part of the column beam joint part, the column beam joint part having a non-diaphragm design where the steel beam is connected on the square steel pipe column.SOLUTION: The present invention provides a column beam joint part where a steel beam is connected to a square steel pipe column, having a non-diaphragm design where a diaphragm at the column beam joint part is omitted by arranging a joint part with greater wall thickness, strength, or both, than the other portions of the square steel pipe column at the portion of the square steel pipe column that includes the panel part of the column beam joint part. At least one side of the four sides of the joint part and another face have different wall thicknesses, strengths, or both.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a non-diaphragm type column-beam joint in which a steel beam is joined to a rectangular steel pipe column, and to a building equipped therewith. [Background technology]

[0002] When long-term loads or seismic loads act on a steel-framed structure, bending moments generated at the ends of steel beams are input to the steel columns. To prevent out-of-plane deformation of the steel columns due to these bending moments, steel plates called diaphragms are welded to the inside or outside of the steel columns. This suppresses deformation of the panel section at the column-beam joint, ensuring the rigidity of the entire frame.

[0003] There are three types of diaphragms for column-beam joints where a steel beam is joined to a rectangular steel pipe column: internal diaphragm type, through diaphragm type, and external diaphragm type. Figure 10 schematically shows a through diaphragm type column-beam joint 8. Figure 11 shows a cross-sectional view of XA-XA in Figure 10. As shown in Figures 10 and 11, in the through diaphragm type column-beam joint 8, in addition to the rectangular steel pipe column 80 and steel beam 2, it is necessary to prepare a steel plate for the through diaphragm 3, and welding the through diaphragm 3 to the rectangular steel pipe column 80 requires construction effort. Similar problems arise in internal diaphragm type and external diaphragm type column-beam joints.

[0004] Therefore, a non-diaphragm type column-beam joint has been proposed for the column-beam joint of steel-framed buildings, which omits the diaphragm that requires time and effort to construct. Figure 12 schematically shows a conventional non-diaphragm type column-beam joint. Figures 13 and 14 show the XIIA-XIIA and XIIB-XIIB sections, respectively, of Figure 12. As shown in Figures 12 to 14, in the non-diaphragm type column-beam joint 9, the diaphragm of the column-beam joint 9 is omitted by providing a joint portion 90P in the portion of the square steel pipe column 90 that includes the panel portion of the column-beam joint 9, with a larger wall thickness than the rest of the square steel pipe column 90.

[0005] In this regard, Patent Document 1 proposes a column-beam joint structure in which a steel column core having a rectangular cross-sectional shape is placed at the column-beam joint between a rectangular steel pipe column and a steel beam, and the thickness of the core is made greater than the thickness of the rectangular steel pipe column, thereby eliminating the need for a diaphragm at the column-beam joint.

[0006] Furthermore, Patent Document 2 proposes a beam-column joint structure that eliminates the need for a diaphragm by making the cross-sectional shape of the steel pipe column octagonal, thereby making out-of-plane deformation of the skin plate less likely to occur compared to steel pipe columns with a normal rectangular cross-section.

[0007] Furthermore, Patent Document 3 proposes a column-beam joint structure in which a steel beam is joined to a steel-reinforced concrete column, and reinforcing bars are provided around a pair of flanges of the steel column to prevent out-of-plane deformation of the flanges of the steel column, thereby eliminating the need for a diaphragm. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2019-60192 [Patent Document 2] Japanese Patent Application Publication No. 11-172765 [Patent Document 3] Japanese Patent Publication No. 2020-12329 [Non-patent literature]

[0009] [Non-Patent Document 1] Architectural Institute of Japan (ed.), "Guidelines for Plastic Design of Steel Structures, 3rd Edition," Architectural Institute of Japan, February 2017, pp. 150-155. [Non-Patent Document 2] Architectural Institute of Japan (ed.), "Design Guidelines for Steel Structure Joints, 3rd Edition," Architectural Institute of Japan, March 2012, pp. 225-226. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] However, in the technology described in Patent Document 1, the wall thickness of the steel column core installed at the column-beam joint is made greater than the wall thickness of the square steel pipe column, which increases the amount of steel material used at the column-beam joint. In addition, the amount of welding required when manufacturing the steel column core by welding the skin plates together increases by the amount of wall thickness of the steel column core.

[0011] Furthermore, the technology described in Patent Document 2 requires considerable effort to manufacture steel pipe columns with an octagonal cross-sectional shape, and if the width of the steel beam is greater than the width of one of the eight sides of the steel pipe column, the connection between the steel column and the steel beam becomes complicated.

[0012] Furthermore, the technology described in Patent Document 3 is limited to steel-reinforced concrete columns, and the process of creating through holes in the steel column to pass reinforcing bars surrounding a pair of flanges of the steel column is cumbersome.

[0013] In view of the above-mentioned problems, the present invention aims to provide a column-beam joint and a building equipped therewith that can reliably prevent out-of-plane deformation of the square steel pipe column due to bending moments input from the end of the steel beam to the panel portion of the column-beam joint, while reducing the amount of steel material used in the column-beam joint and the amount of welding required to manufacture the panel portion of the column-beam joint, in a non-diaphragm type column-beam joint where a steel beam is joined to a square steel pipe column. [Means for solving the problem]

[0014] To solve the above problems, the present invention has the following features.

[0015] [1] In a column-beam joint where a steel beam is joined to a square steel pipe column, a joint portion is provided in a portion of the square steel pipe column including the panel portion of the column-beam joint, where the wall thickness or strength or both are set to be greater than those of other portions of the square steel pipe column. This is a non-diaphragm type column-beam joint where the diaphragm of the column-beam joint is omitted, and at least one of the four sides of the joint portion is set such that the wall thickness or strength or both are different from those of the other sides.

[0016] [2] The joint portion according to [1], wherein the joint portion is composed of a square steel pipe with four-sided welding.

[0017] [3] The joint portion according to [2], wherein the groove depth of the weld between the skin plates constituting the four sides of the joint portion is equal to the wall thickness of the side with the smallest wall thickness among the four sides.

[0018] [4] A building having the column-beam joint according to any one of [1] to [3], wherein the column-beam joint is set such that the wall thickness or strength or both of the four sides of the joint portion are different from each other according to the presence or absence of the steel beam joined to each of the four sides of the joint portion, or the difference in the size or span of the steel beam joined to each of the four sides of the joint portion.

[0019] [5] The building according to [4], wherein the wall thickness or strength or both of each of the four sides of the joint portion are set such that the bending moment generated at the material end of the steel beam adjacent to the joint portion when the steel beam joined to each of the four sides of the joint portion is in a fully plastic state is less than or equal to the full plastic moment of the panel portion of the column-beam joint.

[0020] Here, if no widening sections such as haunches or reinforcing members are provided at the ends of the steel beam, and the steel beam has a uniform cross-section in the direction of the material axis, the steel beam will be in a fully plastic state at the end. Therefore, in this case, the bending moment at the end when the steel beam is in a fully plastic state will be equal to the fully plastic moment of the steel beam. Furthermore, if widening sections such as haunches or reinforcing members are provided at the ends of the steel beam, the steel beam may be in a fully plastic state at the boundary between the part with the widening section or reinforcing member and the part without it. In this case, the bending moment at the end when the steel beam is in a fully plastic state will be greater than the fully plastic moment of the steel beam at the boundary, depending on the bending moment distribution in the direction of the material axis of the steel beam. Therefore, when widening sections such as haunches or reinforcing members are provided at the ends of steel beams, the bending moment at the end of the beam when it is in a fully plastic state shall be calculated taking into consideration that the bending strength of the steel beam changes in the direction of the beam axis due to the provision of widening sections or reinforcing members. [Effects of the Invention]

[0021] According to the column-beam joint and building equipped therewith, the wall thickness and / or strength of at least one of the four faces of the joint portion of the square steel pipe column is set to be smaller than the wall thickness and / or strength of the other faces. Therefore, the wall thickness and / or strength of each of the four faces of the joint portion of the square steel pipe column can be set according to the span, size, etc., of each steel beam joined to the column-beam joint. This makes it possible to reliably prevent out-of-plane deformation of the square steel pipe column due to bending moments input from the end of the steel beam to the panel portion of the column-beam joint, while reducing the amount of steel material used in the column-beam joint and the amount of welding required to manufacture the panel portion of the column-beam joint.

[0022] As a result, the time required for cutting and welding the steel materials that make up the column-beam joints can be reduced. In addition, by reducing the amount of steel materials that make up the column-beam joints, the weight of the building is reduced, and the load due to its own weight is reduced, making economical design possible. Furthermore, cost benefits are obtained by saving storage space for steel materials at steel factories and reducing the weight of steel members when transporting them from steel factories to construction sites. [Brief explanation of the drawing]

[0023] [Figure 1] Figure 1 is a schematic side view showing the column-beam joint according to the present invention. [Figure 2] Figure 2 is an IA-IA cross-sectional view in Figure 1. [Figure 3] Figure 3 is an IB-IB cross-sectional view in Figure 1. [Figure 4] Figure 4 is a schematic cross-sectional view showing the main part of the column-beam joint according to the present invention. [Figure 5] Figure 5 is a schematic horizontal cross-sectional view showing a case where the steel beams joined at the column-beam joint are of different sizes. [Figure 6] Figure 6 is a schematic side view showing the bending moment distribution generated in a steel beam due to horizontal loads acting on a building, when no haunches are provided at the ends of the steel beams. [Figure 7] Figure 7 is a schematic plan view showing the location of plastic hinges formed on a steel beam due to horizontal loads acting on a building, when no haunches are provided at the ends of the steel beams. [Figure 8] Figure 8 is a schematic side view showing the bending moment distribution generated in a steel beam due to horizontal loads acting on a building, when a horizontal haunch is provided at the end of the steel beam. [Figure 9] Figure 9 is a schematic plan view showing the location of a plastic hinge formed on a steel beam due to the horizontal load acting on the building, when a horizontal haunch is provided at the end of the steel beam. [Figure 10] Figure 10 is a schematic side view showing a conventional column-beam joint with a through diaphragm. [Figure 11] Figure 11 is a cross-sectional view taken along line XA-XA in Figure 10. It is a side view shown. [Figure 12] Figure 12 is a schematic side view showing a conventional non-diaphragm type column-beam joint. [Figure 13] Figure 13 is a cross-sectional view of the XIIA-XIIA section in Figure 12. [Figure 14]Figure 14 is a cross-sectional view of the XIIB-XIIB section in Figure 12. [Modes for carrying out the invention]

[0024] Hereinafter, embodiments of the column-beam joint and a building equipped therewith according to the present invention will be described in detail with reference to the drawings.

[0025] Figure 1 schematically shows a side view of a column-beam joint according to one embodiment of the present invention. Figures 2 and 3 show the IA-IA and IB-IB sections of Figure 1, respectively.

[0026] As shown in Figures 1 to 3, the column-beam joint 1 of this embodiment is a non-diaphragm type column-beam joint in which a diaphragm is omitted. In the column-beam joint 1 in which a steel beam 2 is joined to a square steel pipe column 10, a joint portion 10P is provided in the portion of the square steel pipe column 10 that includes the panel portion of the column-beam joint 1, with a wall thickness greater than that of the other parts of the square steel pipe column 10. As a result, the necessary strength and deformation performance of the column-beam joint 1 are ensured even without a diaphragm.

[0027] Figure 4 schematically shows the main part of the column-beam joint 1 of this embodiment. As shown in Figure 4, in the column-beam joint 1 of this embodiment, the joint portion 10P of the square steel pipe column 10 is made of a four-sided welded square steel pipe formed by combining four skin plates 11 to 14. The four-sided welded square steel pipe is manufactured by joining the four skin plates 11 to 14 together by welding from the outside with a backing plate 16 provided on the inside of the corner portion to form a welded portion 15.

[0028] In this embodiment, the column-beam joint 1 and the building equipped therewith are assumed to have 1 to 4 steel beams 2 joined to the four sides of the joint 10P. The skin plates 11 to 14 that make up the four sides of the joint 10P are set to have different thicknesses depending on whether or not there are steel beams 2 joined to each of the four sides of the joint 10P, or on the difference in size or span of the steel beams 2 joined to each of the four sides of the joint 10P. At this time, the thicknesses of each of the skin plates 11 to 14 that make up the four sides of the joint 10P are set so that the panel portion of the column-beam joint 1 does not yield earlier than the steel beams 2. In the example shown in Figures 3 and 4, the thicknesses t2 and t4 of the skin plates 12 and 14 that make up the two sides of the joint 10P to which steel beams 2 are not joined are set to be smaller than the thicknesses t1 and t3 of the skin plates 11 and 13 that make up the two sides to which steel beams are joined.

[0029] Furthermore, as shown in Figure 4, the grooves of the welded joints 15 between the skin plates 11-14 that constitute the four sides of the joint 10P are provided at both ends of the skin plate 12 and 14, which have the smallest wall thickness among the skin plates 11-14. The depth of these grooves is set to be equal to the wall thicknesses t2 and t4 of the skin plate 12 and 14, which have the smallest wall thickness among the skin plates 11-14. This is preferable because it reduces the amount of welding required when manufacturing the four-sided welded square steel pipe that constitutes the joint 10P by welding together the four skin plates 11-14, thereby reducing the cost of welding wire and welding time. In addition, as a result of reducing the amount of welding required when manufacturing the four-sided welded square steel pipe that constitutes the joint 10P, the occurrence of welding defects in the welded joint can be suppressed. Therefore, the risk of the strength of the column-beam joint being compromised due to welding defects can be reduced.

[0030] In addition, the joint part 10P of the square steel pipe column 10 has a larger wall thickness than other parts of the square steel pipe column 10. However, the height of the joint part 10P is preferably set according to the number of steel frame beams 2 joined to the four sides of the joint part 10P and the size or span of the steel frame beams 2 joined to each of the four sides of the joint part 10P. In particular, it is preferable that the height of the joint part 10P is not less than the beam depth of the steel frame beam 2 so that the steel frame beam 2 does not protrude above and below the joint part 10P.

[0031] In the column-beam joint 1 of the present embodiment and the building provided with the same, when the steel frame beams 2 joined to each of the four sides of the joint part 10P are in a fully plastic state, the bending moment M generated at the material ends of the steel frame beams 2 adjacent to the joint part 10P b,p is such that the full plastic moment M of the panel part of the column-beam joint j,p It is preferable that the wall thicknesses of the skin plates 11 to 14 constituting the four sides of the joint part 10P are set as follows. By doing so, it is possible to suppress the plasticization of the panel part of the column-beam joint 1 from occurring first during an earthquake, and to realize a collapse mode of the overall collapse type in which plastic hinges are formed at the material ends of the steel frame beams 2. As a result, the energy absorption capacity of the building can be maximized, and a highly earthquake-resistant structure can be obtained.

[0032] Fig. 5 schematically shows a case where four steel frame beams 2a to 2d are joined to the column-beam joint 1 and the sizes of these steel frame beams 2a to 2d are different from each other. As shown in Fig. 5, when the steel frame beams 2a to 2d are attached to the four sides of the joint part 10P, the bending moments generated at the material ends of the steel frame beams 2a to 2d adjacent to the joint part 10P when each of the steel frame beams 2a to 2d is in a fully plastic state are respectively M p1 , M p12 , M p3 , M p4 . At this time, these bending moments M p1 , M p12 , M p3 , M p4 are such that M p1 ≦M p2 ≦M p3 ≦M p4Assuming that the above relationship is satisfied, it is preferable to set the thicknesses t1, t2, t3, and t4 of the skin plates 11 to 14 to which the steel beams 2a to 2d are joined to such that the relationship t1 ≤ t2 ≤ t3 ≤ t4 (except in the case where t1 = t2 = t3 = t4) is satisfied.

[0033] Bending moment M at the end of the steel beam 2 when it is in a fully plastic state. b,p This can be calculated, for example, by the method described in Non-Patent Document 1.

[0034] Here, Figures 6 and 7 schematically show the bending moment distribution generated in the steel beam 2 due to the horizontal load acting on the building, and the position P of the plastic hinge formed in the steel beam 2, respectively, when no haunch is provided at the end of the steel beam 2. Furthermore, Figures 8 and 9 schematically show the bending moment distribution generated in the steel beam due to the horizontal load acting on the building, and the position P of the plastic hinge formed in the steel beam, respectively, when a horizontal haunch 2h is provided at the end of the steel beam.

[0035] As shown in Figures 6 and 7, if no widening sections such as haunches or reinforcing members are provided at the ends of the steel beam 2, and the steel beam 2 has a uniform cross-section in the direction of the material axis, the steel beam 2 will be in a fully plastic state at the end. Therefore, in this case, the bending moment at the end of the steel beam 2 when it is in a fully plastic state will be equal to the fully plastic moment of the steel beam 2.

[0036] Furthermore, as shown in Figures 8 and 9, when widening sections such as horizontal haunches 2h or reinforcing members are provided at the ends of the steel beam, the steel beam 2 may enter a fully plastic state at the boundary between the section with the widening section or reinforcing member and the section without it. In this case, the bending moment at the end of the steel beam 2 when it is in a fully plastic state will be greater than the fully plastic moment of the steel beam at the boundary location, depending on the bending moment distribution in the axial direction of the steel beam 2.

[0037] Therefore, when widening sections such as horizontal haunches 2h or reinforcing members are provided at the ends of the steel beam 2, the bending strength of the steel beam 2 changes in the direction of the material axis due to the provision of widening sections or reinforcing members, and the bending moment M at the end of the steel beam 2 when the steel beam 2 is in a fully plastic state must be considered. b,p The following will be calculated:

[0038] Furthermore, the full plastic moment M of the panel portion of the column-beam joint 1 j,p This is the value of the bending moment acting on the panel when the entire panel undergoes shear deformation and reaches its full plastic strength, and can be calculated, for example, by the strength evaluation formula for the panel of a column-beam joint described in Non-Patent Document 2.

[0039] The steel material constituting the joint section 10P does not necessarily have to be the same type as the steel material constituting the other square steel pipe columns 10 and steel beams 2. The type of steel should be selected according to the shape of the joint section 10P and the forces acting on the panel section of the column-beam joint 1.

[0040] Furthermore, the square steel pipe column 10, including the joint portion 10P, may be a hollow square steel pipe or a concrete-filled steel pipe.

[0041] In this embodiment, the column-beam joint 1 and the building equipped therewith, the wall thickness of at least one of the four faces of the joint portion 10P of the square steel pipe column 10 is set to be smaller than the wall thickness of the other faces. Therefore, the wall thickness of each of the four faces of the joint portion 10P of the square steel pipe column 10 can be set according to the span, size, etc., of each steel beam 2 joined to the column-beam joint 1. This makes it possible to reliably prevent out-of-plane deformation of the square steel pipe column 10 due to bending moments input from the ends of the steel beams 2 to the panel portion of the column-beam joint 1, while reducing the amount of steel material used in the column-beam joint 1 and the amount of welding required to manufacture the panel portion of the column-beam joint 1.

[0042] In the above embodiment, an example was described in which the thicknesses t1, t2, t3, and t4 of the four sides of the joint 10P are set to be different from each other, depending on whether or not a steel beam 2 is joined to each of the four sides of the joint 10P, or the difference in size or span of the steel beam 2 joined to each of the four sides of the joint 10P. However, the column-beam joint of the present invention is not limited to this, and the strength, or both the thickness and strength, of the four sides of the joint 10P may be set to be different from each other, depending on whether or not a steel beam 2 is joined to each of the four sides of the joint 10P, or the difference in size or span of the steel beam 2 joined to each of the four sides of the joint 10P. [Explanation of Symbols]

[0043] 1, 8, 9 Column beam joint 10, 80, 90 square steel pipe columns 10P, 90P joint section 11-14 Skin Plates 15. Welded section 16. Backing metal 2, 2a~2d Steel beams 2h horizontal haunch 3. Through diaphragm P Plastic hinge formation position M b,p The bending moment generated at the end of a steel beam adjacent to a joint when the steel beam is in a fully plastic state. M j,p However, the full plastic moment of the panel section at the column-beam joint

Claims

1. In a column-beam joint where a steel beam is joined to a rectangular steel pipe column, a joint portion is provided in the portion of the rectangular steel pipe column including the panel portion of the column-beam joint, where the wall thickness, strength, or both are set to be greater than the other portions of the rectangular steel pipe column, thereby creating a non-diaphragm type column-beam joint in which the diaphragm of the column-beam joint is omitted. The thickness and / or strength of at least one of the four faces of the joint and the other faces are set to be different from each other (except in cases where the strength of a pair of opposing faces of the four faces of the joint is the same, and the strength of the other pair of opposing faces of the four faces of the joint is the same, and the strength of the pair and the strength of the other pair are set to be different from each other), The bending moment M generated at the material end of the steel frame beam adjacent to the doorway when each of the steel frame beams joined to each of the four sides of the doorway is in a fully plastic state p1 , Mp2, M p3 , M p4 (However, when the steel frame beam is not joined to some of the four sides of the doorway, the bending moment M p1 , Mp2, M p3 , M p4 for the unjoined steel frame beam is set to 0) satisfies the relationship of M p1 ≤ M p2 ≤ M p3 ≤ M p4 and further, the thickness t 1 , t 2 , t 3 , t 4 of each of the four sides of the doorway and the strength σ 1 , σ 2 , σ 3 , σ 4 of each of the four sides of the doorway satisfy the relationship of t 1 ≤ t 2 ≤ t 3 ≤ t 4 (however, excluding the case where t 1 = t 2 [[ID=四十八]] = t 3 = t 4 ) or the relationship of σ 1 ≤ σ 2 ≤ σ 3 ≤ σ 4 (however, excluding the case where σ 1 = σ 2 = σ 3 = σ 4 ) or both relationships are set to be satisfied, the column-beam joint

2. The column-beam joint according to claim 1, wherein the joint portion is made of a four-sided welded square steel pipe.

3. A building having a column-beam joint as described in claim 1 or 2, A building in which the column-beam joint is set such that the thickness and / or strength of the four sides of the joint differ from one another, depending on whether or not the steel beams are joined to each of the four sides of the joint, or the difference in size or span of the steel beams joined to each of the four sides of the joint.

4. The building according to claim 3, wherein the thickness and / or strength of each of the four faces of the joint is set such that when the steel beams joined to each of the four faces of the joint are in a fully plastic state, the bending moment generated at the end of the steel beam adjacent to the joint is less than or equal to the fully plastic moment of the panel portion of the column-beam joint.

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