Roof member joint structure

Abstract

To efficiently improve lateral buckle strength of a beam with reduced construction cost.SOLUTION: A roof member joint structure is a joint structure between an H-shaped steel beam as a support member and a roof member. The roof member is joined to the H-shaped steel beam with first joint parts that are arranged in the longitudinal direction of the H-shaped steel beam and with second joint parts that have higher rigidity and strength than the first joint part. The second joint parts are arranged, where L is the length of the H-shaped steel beam, at both positions of 0.25L±0.1L and 0.75L±0.1L from one end of the H-shaped steel beam.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a joint structure between a support member and a roof member. [Background technology]

[0002] Dry roof structures are known in which roofing components, such as corrugated deck plates, are placed on purlins. For example, Patent Document 1 describes a technique in which purlins are attached to the underside of a deck plate to form the roof body, and the purlins are then attached to fire-resistant beams of a building. In the technique described in Patent Document 1, drilling and tapping screws are used to join the deck plate and the purlins. Other joints that can be used include burn-through plug welding and riveted rivets. Patent Document 2 proposes a technique in which a plate-like member is inserted between the deck plate and a nut that is threaded onto a stud bolt that extends through the deck plate from the opposite side of the support member, in order to form a friction joint between the deck plate and the support member that exhibits stable rigidity and strength while maintaining workability.

[0003] On the other hand, as described in Non-Patent Document 1, for example, a technique is known in which floor slabs, roof panels, etc. are continuously attached in the longitudinal direction of the beam to exert a restraining effect against lateral buckling deformation and improve the lateral buckling strength of the beam. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-282190 [Patent Document 2] Japanese Patent Publication No. 2022-127322 [Non-patent literature]

[0005] [Non-Patent Document 1] Yoshihiro Kimura et al., "Lateral Buckling Load of H-Shaped Beams with Continuous Bracing on the Top Flange Subjected to Inclined Bending Moment and Compressive Axial Force and the Effect of Continuous Bracing on Horizontal and Rotational Restraint," Journal of Structural Engineering, Architectural Institute of Japan, Vol. 82, No. 741, pp. 1799-1809, November 2017 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, when connecting roof elements to H-shaped steel beams via multiple joints to prevent lateral buckling of the beams, the rigidity of the joints is important. For example, if the joints are only made with burn-through plug welds, localized deformation occurs in the roof elements, making it difficult to ensure rotational rigidity. This raises the risk of insufficient suppression of lateral buckling of the beams. For example, using joints with improved rigidity and strength, such as those described in Patent Document 2, would strengthen the restraint effect against lateral buckling, but using such joints for all joints would significantly increase construction costs.

[0007] Therefore, an object of the present invention is to provide a joint structure for roof members that can improve the lateral buckling resistance of beams in a simple manner while reducing construction costs. [Means for solving the problem]

[0008] [1] A joint structure between an H-shaped steel beam, which is a supporting member, and a roof member, wherein the roof member is joined to the H-shaped steel beam by a first joint arranged in the longitudinal direction of the H-shaped steel beam and a second joint having higher rigidity than the first joint, and where, assuming that the length of the H-shaped steel beam is L, the second joint is located at both a position 0.25L±0.1L and a position 0.75L±0.1L from one end of the H-shaped steel beam. [2] A joint structure between an H-shaped steel beam, which is a supporting member, and a roof member, wherein the roof member is joined to the H-shaped steel beam by a first joint arranged in the longitudinal direction of the H-shaped steel beam and a second joint having higher rigidity than the first joint, and the roof member is constituted by deck plates having one or more uneven shapes arranged so that the extension direction of the uneven shapes is perpendicular to the longitudinal direction of the H-shaped steel beam, and when the length of the H-shaped steel beam is L, the first deck plates corresponding to both positions 0.25L±0.1L and 0.75L±0.1L from one end of the H-shaped steel beam have at least one of the second joints. [3] The first deck plate comprises two convex portions, a central recess provided between the convex portions in the center of the longitudinal direction, and end recesses provided at both ends in the longitudinal direction, and the second joint is provided in one of the end recesses of the first deck plate and the central recess. [2] The joining structure of a roof member described in [2]. [4] The first deck plate comprises two convex portions, a central recess provided between the convex portions in the center of the longitudinal direction, and end recesses provided at both ends of the longitudinal direction, and the second joint is provided in both of the end recesses of the first deck plate. [2] The joint structure of a roof member described in [2] [5] The first deck plate comprises two convex portions, a central recess provided between the convex portions in the center of the longitudinal direction, and end recesses provided at both ends of the longitudinal direction, and the second joint is provided in all of the recesses of the first deck plate. [2] The joining structure of a roof member described in [2]. [6] The first deck plate comprises three convex portions, two intermediate concave portions between the convex portions, and two end concave portions at both ends in the longitudinal direction, and the second joint portion is provided in both the concave portion of one of the end concave portions of the first deck plate and the intermediate concave portion. [7] The first deck plate comprises three convex portions, two intermediate concave portions between the convex portions, and two end concave portions at both ends in the longitudinal direction, and the second joint portion is provided in both of the end concave portions of the first deck plate. [2] The joint structure of a roof member described in [2]. [8] The first deck plate comprises three convex portions, two intermediate concave portions between the convex portions, and two end concave portions at both ends in the longitudinal direction, and the second joint portion is provided in all of the concave portions of the first deck plate. [2] The joint structure of a roof member described in [2]. [9] A joint structure for a roof member described in any one of [3] to [8], wherein the first joint is one burn-off plug weld per recess in the deck plate, and the second joint is two burn-off plug welds per recess in the deck plate. [Effects of the Invention]

[0009] According to the above configuration, in a roof member joint structure in which a roof member is joined to an H-shaped steel beam by multiple joints arranged in the longitudinal direction of the H-shaped steel beam, by partially arranging highly rigid joints at appropriate positions, the lateral buckling strength of the H-shaped steel beam can be improved in a simple manner while reducing construction costs. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a joining structure for roof members according to one embodiment of the present invention. [Figure 2] 1 is a plan view of a joining structure for roof members according to an embodiment of the present invention; [Figure 3] 1 is a perspective view of a joining structure for roof members according to an embodiment of the present invention; [Figure 4A] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 4B] FIG. 4 is a cross-sectional view taken along line BB in FIG. [Figure 4C] FIG. 4 is a cross-sectional view taken along line CC in FIG. [Figure 5]FIG. 10 is a diagram illustrating the position of a first deck plate when multiple deck plates are arranged. [Figure 6A] FIG. 10 is a diagram showing an example of the arrangement of second joints in the corresponding deck plate. [Figure 6B] FIG. 10 is a diagram showing an example of the arrangement of second joints in the corresponding deck plate. [Figure 6C] FIG. 10 is a diagram showing an example of the arrangement of second joints in the corresponding deck plate. [Figure 6D] FIG. 10 is a diagram showing an example of the arrangement of second joints in the corresponding deck plate. [Figure 6E] FIG. 10 is a diagram showing an example of the arrangement of second joints in the corresponding deck plate. [Figure 7A] 10A and 10B are diagrams showing other examples of arrangement of the second joint portion. [Figure 7B] 10A and 10B are diagrams showing other examples of arrangement of the second joint portion. [Figure 7C] 10A and 10B are diagrams showing other examples of arrangement of the second joint portion. [Figure 8A] FIG. 10 is a diagram showing a specification in which deck plates are stacked on top of each other without having an engaging portion. [Figure 8B] FIG. 10 is a diagram showing a specification in which deck plates are stacked on top of each other without having an engaging portion. [Figure 9] FIG. 10 is a diagram showing a modified example of an embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing a modified example of an embodiment of the present invention. [Figure 11] FIG. 10 is a diagram showing a modified example of an embodiment of the present invention. [Figure 12] FIG. 10 is a diagram showing an example of a tight frame in which the rigidity is increased only in a part of the frame. [Figure 13] FIG. 10 is a schematic diagram illustrating the placement of joints in the analysis. [Figure 14] 10 is a graph showing the analysis results for H300. [Figure 15] 10 is a graph showing the analysis results for H200, H250, H350, and H400. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] Fig. 1 is a cross-sectional view of a joining structure for roofing members according to one embodiment of the present invention, Fig. 2 is a plan view of the joining structure for roofing members, Fig. 3 is an enlarged perspective view of a second joining portion (described later) of the joining structure for roofing members, and Figs. 4A to 4C are cross-sectional views taken along lines AA, BB, and CC in Fig. 3, respectively. As shown in Figures 1 and 2, the roof member joint structure 100 is a joint structure between an H-shaped steel beam 2, which is a support member, and a deck plate 1, which is an example of a roof member, and the deck plate 1 is joined to the H-shaped steel beam 2 by a plurality of joints N1 to N13 arranged in the longitudinal direction (x direction) of the H-shaped steel beam 2.

[0013] The deck plate 1 is a corrugated thin plate with alternating trapezoidal convex portions 11 and concave portions 12 extending parallel to one another, creating an uneven shape. The deck plate is arranged so that the direction of extension of the concave and convex portions is perpendicular to the longitudinal direction of the H-shaped steel beam 2. The thickness of the deck plate 1 is, for example, 0.8 mm to 1.6 mm, but is not limited to this example. Multiple deck plates 1 may be laid side by side in the longitudinal or transverse direction of the H-shaped steel beam 2.

[0014] The H-shaped steel beam 2 includes flanges 21A, 21B and a web 22. In the illustrated example, the recess 12 of the deck plate 1 is placed on the surface of the flange 21A opposite to the web 22. The x direction shown in each figure is the direction of the corrugation of the deck plate 1 (which coincides with the axial direction of the H-shaped steel beam 2), the y direction is the direction perpendicular to the x direction in the horizontal plane (which coincides with the width direction of the H-shaped steel beam 2), and the z direction is the vertical direction.

[0015] The H-shaped steel beam 2 in this embodiment is an H-shaped steel beam (hereinafter sometimes referred to as H300) with a height of 300 mm, width of 150 mm, web thickness of 6.5 mm, flange thickness of 9 mm, and a slenderness ratio of 70. The slenderness ratio λ is the ratio of the radius of inertia i to the buckling length Lb of the member (λ = Lb / i). The radius of inertia i can be calculated from the moment of inertia I and the cross-sectional area A by i = √(I / A).

[0016] A plurality of (13 in this embodiment) joints N1 to N13 are arranged at approximately equal intervals in the longitudinal direction of the H-shaped steel beam 2. The joints N1 to N13 are composed of first joints (N1 to N3, N5 to N9, and N11 to N13 in this embodiment) and second joints (N4 and N10 in this embodiment) that have higher rigidity than the first joints. If the length of the H-shaped steel beam 2 is L, the second joints are located at both a position 0.25L±0.1L (for example, position N4 in this embodiment) and a position 0.75L±0.1L (for example, position N10 in this embodiment) from one end of the H-shaped steel beam 2, and the remainder is the first joint. In other words, the second joints, which have higher rigidity than the first joints, are located partially.

[0017] In the example shown in Figures 1 and 2, the first joints N1 to N3, N5 to N9, and N11 to N13 are formed by one burn-off plug weld per joint between the recess 12 of the deck plate 1 and the flange 21A, and the second joints N4 and N10 are formed by two burn-off plug welds per joint.

[0018] At the second joints N4 and N10, the number of times the above-mentioned burnout plug welding is performed is large, so the construction cost per location is higher than the construction cost per location of the first joint. Therefore, by partially arranging the second joints as described above and using the first joints for the rest, the construction cost of the entire joint structure can be reduced. As shown in the examples described below, if the second joints are located at both positions 0.25L±0.1L and 0.75L±0.1L from one end of the H-shaped steel beam 2, lateral buckling of the H-shaped steel beam 2 can be effectively restrained.

[0019] In this embodiment, by doubling the number of burn-out plug welds, it is possible to reliably increase the rigidity of the H-shaped steel beam 2 even when it is twisted in either direction. It is also possible to reliably exert rigidity even when a gap occurs between the H-shaped steel beam 2 and the deck plate 1 due to manufacturing or construction errors. Furthermore, it is possible to exert rigidity even when the H-shaped steel beam 2 is twisted alternately on both sides.

[0020] Figures 4A to 4C show the details of the second joint. As shown in Figures 4A to 4C, the second joint is formed in the recess 12 of the deck plate 1 by two burnt-out plug welds 7 that are spaced apart in the extension direction of the recess 12 (y direction, width direction of the H-shaped steel beam 2). Since the deck plate 1 is a thin plate, there is no need to pre-drill holes in the deck plate 1, and no stud bolts or plates are required, so it can be formed at low cost.

[0021] In one embodiment of the present invention as described above, in a roof member joint structure 100 in which a deck plate 1 is joined to an H-shaped steel beam 2 by a plurality of joints N1 to N13 arranged in the longitudinal direction of the H-shaped steel beam 2, by partially arranging a second joint with high rigidity at an appropriate position, the lateral buckling strength of the H-shaped steel beam 2 can be improved in a simple manner while reducing construction costs.

[0022] In the above embodiment, the first joint is formed by one refractory weld per recess, and the second joint is formed by two refractory welds per recess, but this is not limitative as long as the second joint is more rigid than the first joint. For example, the first joint may be formed by one rivet per recess, and the second joint may be formed by two rivets per recess.

[0023] In addition, when multiple deck plates 1 are arranged in the longitudinal direction of the H-shaped steel beam 2, the deck plates corresponding to both positions 0.25L±0.1L and 0.75L±0.1L from one end of the H-shaped steel beam 2 (hereinafter referred to as the first deck plate) may be configured to have at least one second joint.

[0024] For example, as shown in Figure 5, if the roof member is composed of 10 deck plates 1, the first deck plate 1A1 corresponds to a position 0.25L±0.1L from one end of the H-shaped steel beam 2, and the first deck plate 1A2 corresponds to a position 0.75L±0.1L. If the width of the deck plate is short and multiple first deck plates are located 0.25L±0.1L from one end of the H-shaped steel beam 2, it is sufficient that at least one of the multiple first deck plates has the second joint. To prioritize the rigidity of the joint structure, all corresponding first deck plates may have the second joint.

[0025] 6A to 6E are diagrams showing examples of the arrangement of second joints on the corresponding deck plate 1. In FIG. 6, "x" indicates the location where the second joint is to be provided. Second joints are provided at all of the "x"s. At least one of the "x"s may be the second joint, in which case the others may be the first joints. In the example shown in FIGS. 6A to 6E, the deck plate 1 comprises two protrusions 11, a central recess 12A located between the protrusions 11 and in the center of the H-shaped steel beam 2 in the longitudinal direction, and end recesses 12B located at both ends of the H-shaped steel beam 2 in the longitudinal direction. The end recesses 12B are provided with engagement portions 14 that engage adjacent deck plates 1. The central recess 12A may be provided with a rib 15, in which case joints can be formed on one and the other sides of the rib 15. In FIG. 6, the locations other than the "x" may or may not have first joints.

[0026] The first example shown in Figure 6A is the most suitable example, in which second joints are placed in each of the recesses 12B at both ends and on one side of the central recess 12A among the recesses 12 of the corresponding deck plate 1. The first example is the most suitable when taking into consideration rigidity and construction costs, as it can efficiently improve rigidity by suppressing lifting of the entire deck plate (ends and center). The second example shown in Figure 6B is the next most preferable example after the first example, and has second joints located on one side of the recesses 12B at both ends and one side of the central recess 12A of the corresponding recesses 12 of the deck plate 1. In the second example, by joining the female side (the upper side of the engagement portion 14) at the end of the deck plate, it is possible to prevent the adjacent male side from floating.

[0027] The third example shown in Figure 6C is the next most suitable example after the second example, and has second joints located in each of the recesses 12B at both ends of the corresponding deck plate 1 and on one side and the other side of the central recess 12A. In other words, second joints are located in all possible locations. The third example has the highest rigidity because joints are located in all recesses 12. The fourth example shown in Figure 6D is the next most suitable example after the third example, in which second joint portions are placed only in the recesses 12B at both ends of the recesses 12 of the corresponding deck plate 1. In the fourth example, although lifting occurs in the center of the deck plate, because both ends are joined, lifting of one side of the deck plate does not occur, and lifting of the entire deck plate is suppressed. In the fifth example shown in Figure 6E, second joints are located on one side of the recesses 12B at both ends and on one and the other side of the central recess 12A of the recesses 12 of the corresponding deck plate 1. The fifth example is a specification to be selected when the widths of the recesses 12B are not uniform (for example, when one side is significantly narrower and there is not enough space to perform the joint).

[0028] The builder can select the arrangement of the second joint in the corresponding deck plate 1 depending on the required strength and cost.

[0029] 7A to 7C are diagrams showing other examples of the arrangement of second joints in the corresponding deck plate 1. In FIG. 7, "x" indicates the location where the second joint is provided. Second joints are provided at all of the "x"s. At least one of the "x"s may be the second joint, in which case the others may be the first joints. In the example shown in FIGS. 7A to 7C, the deck plate 1 consists of three protrusions 11, two intermediate recesses 12A provided between the protrusions 11, and end recesses 12B provided at both ends of the H-shaped steel beam 2 in the longitudinal direction. In addition, the locations other than the "x" in FIG. 7 may or may not have first joints.

[0030] The first example shown in Figure 7A is the most suitable example, in which second joints are placed in each of the recesses 12B at both ends and both of the two middle recesses 12A of the corresponding deck plate 1. In other words, second joints are placed in all of the recesses 12. The first example is a specification that achieves the highest rigidity by placing second joints in all of the recesses 12 to suppress lifting of the entire deck plate (ends and center).

[0031] The second example shown in Figure 7B is the next most suitable example after the first example, and has a second joint located on one side of the recesses 12B at both ends of the corresponding deck plate 1 recesses 12, as well as in both of the two intermediate recesses 12A. In the second example, by joining the female side (the side that is on top of the engagement portion 14) at the end of the deck plate, it is possible to prevent the adjacent male side from lifting. The second example can also be selected when the width of the joining area is narrow and joining is not possible.

[0032] The third example shown in Figure 7C is the next most suitable example after the second example, in which second joints are placed only in the recesses 12B at both ends of the recesses 12 of the corresponding deck plate 1. In the third example, although lifting occurs in the center of the deck plate, because both ends are joined, lifting of one side of the deck plate does not occur, and lifting of the entire deck plate is suppressed.

[0033] While the above-described examples of the present invention are all intended for specifications that have engaging portions 14 and recesses at both ends, as shown in Figure 8A, it is also possible to effectively restrain lateral buckling of the H-shaped steel beam 2 by similarly arranging a second joint portion in a specification in which deck plates 1 are overlapped on top of each other without engaging portions 14. As shown in Figure 8B, if the overlapping flanges are short, welding is not performed.

[0034] Below, a description will be given of a modification of the above-described embodiment of the present invention. In the first modified example shown in Figure 9, the second joint, which is more rigid than the first joint, has a deck plate 1 placed on an H-shaped steel beam 2 and is composed of a stud bolt 3, a nut 4, a washer 5, and a bearing plate 6.

[0035] One end of the stud bolt 3 is welded to the flange 21A of the H-shaped steel beam 2, and extends through the recess 12 in the deck plate 1. Specifically, for example, with the deck plate 1 placed on the H-shaped steel beam 2, the stud bolt 3 is welded from above the deck plate 1 using any of various stud welding methods. As already mentioned, the deck plate 1 is a thin plate, so by welding the stud bolt 3 from above the deck plate 1, the deck plate 1 is melted and holes are drilled while the stud bolt 3 is welded to the H-shaped steel beam 2. Therefore, in this modified example, there is no need to pre-drill holes in the deck plate 1 at the joint.

[0036] Nut 4 is screwed onto stud bolt 3 from the end opposite H-shaped steel beam 2, and washer 5 is inserted between nut 4 and deck plate 1. By inserting washer 5 onto stud bolt 3 and then screwing nut 4 onto it, and tightening nut 4 while in contact with washer 5, tension is introduced into stud bolt 3, and a frictional joint can be formed between deck plate 1 and H-shaped steel beam 2.

[0037] In addition to a washer 5, a bearing plate 6 is interposed between the nut 4 and the deck plate 1. The bearing plate 6 extends perpendicular to the direction of the corrugations of the deck plate 1, that is, parallel to the convex portions 11 and concave portions 12. The width of the bearing plate 6 corresponds to the width of the concave portions 12, for example.

[0038] In a second modified example shown in Figure 10, the second joint is composed of a support plate 6 and a weld 7. A vertical through hole 61 is formed in the support plate 6, and the weld 7 is formed by filling the interior of the through hole 61 with weld metal, for example, by burn-out plug welding. The weld 7 passes through the recess 12 in the deck plate 1 and contacts the inner wall surface of the through hole 61 and the flange 21A of the H-shaped steel beam 2. The weld 7 joins the inner wall surface of the through hole 61, the recess 12 in the deck plate 1, and the upper surface of the flange 21A.

[0039] Because the deck plate 1 is a thin plate, it is possible to form the welded portion 7 by, for example, drilling a hole that connects the inside of the through hole 61 to the surface of the flange 21A while melting the deck plate 1 using burn-out plug welding. Therefore, in this embodiment, there is no need to pre-drill holes in the deck plate 1 at the joint.

[0040] 11, multiple support plates 6A, 6B are arranged in the extension direction (y direction) of the recess 12. In the illustrated example, a vertical through hole 61A is formed in the support plate 6A, and a vertical through hole 61B is also formed in the support plate 6B. Furthermore, a weld 7A is formed through the recess 12 of the deck plate 1 and contacts the inner wall surface of the through hole 61A and the flange 21A of the H-shaped steel beam 2, and a weld 7B is formed similarly in contact with the inner wall surface of the through hole 61B and the flange 21A. Even when multiple support plates 6A, 6B are arranged separately in this way and welds 7A, 7B are formed between each support plate and the support member, local deformation around the welds is prevented, and stable rigidity can be exerted against rotational deformation of the support member.

[0041] In addition, the deck plate 1 and the H-shaped steel beam 2 do not need to be directly joined, and height-adjusting raising materials (channel steel, lip channel steel, etc.) or tight frames may be installed between the deck plate 1 and the H-shaped steel beam 2.

[0042] Furthermore, the roof member is not limited to the corrugated deck plate 1, and it is also possible to use, for example, a flat deck with a flat upper surface and ribs on the lower surface. As shown in Figure 9, the flat deck 30 is connected to the H-shaped steel beam 2 using a tight frame 9. Specifically, the lower surface of the plate-shaped portion 31 of the flat deck 30, which is made up of a plate-shaped portion 31 and a rib portion 32, is joined to the upper surfaces of the convex portions 91A, 91B of the tight frame 9, and the upper surface of the flange 21A of the H-shaped steel beam 2 is joined to the lower surface of the concave portion 92 of the tight frame 9. In this embodiment, the rigidity of a portion can be increased by making the plate thickness of a portion of the protrusions 91A thicker than that of the other protrusions 91B. Alternatively, the rigidity may be increased by widening the plate width of a portion of the tight frame 9.

[0043] [Analysis of joint structure] Next, the analysis performed to examine the placement of the second joint will be described. For the study, an eigenvalue analysis of bending (bottom flange compression) was carried out for a joint structure in which the deck plate was connected to the H-shaped steel beam by the first and second joints, while changing the position of the second joint. As shown in Figure 13, 13 deck plates 1 were arranged at equal intervals on an H-shaped steel beam 2, and one joint was provided on each deck plate 1, resulting in joints N1 to N13 arranged at equal intervals, with some joints being used as second joints with higher rigidity.Then, we confirmed what trends were observed in the results of the elastic buckling load obtained by eigenvalue analysis.

[0044] [Analysis conditions] H-shaped steel beam: height 300mm x width 150mm, web thickness 6.5mm, flange thickness 9mm H-beam length: 7800mm Continuous stiffening: 600mm pitch Horizontal spring: 72.6kN / mm Rotational stiffness of the first joint: 22.6 kNm / rad Rotational stiffness of the second joint: 73.8kNm / rad

[0045] The rotational rigidity of the first joint is an experimental value obtained by welding the H-shaped steel beam and deck plate together using a burn-out plug weld, then applying a twist to the H-shaped steel beam to confirm the rotational rigidity of the joints on each of the deck plates. The rotational rigidity of the second joint is an experimental value obtained by joining an H-shaped steel beam and a deck plate using a joint formed by a bearing plate 6 and two burn-off plug welds 7 as described in the second variant of this specification (Figure 10), which is provided on each deck plate, and then applying torsion to the H-shaped steel beam to confirm the rotational rigidity of the joint. The horizontal springs are set in the same locations as the first and second joints, and in this analysis, the value is calculated by multiplying Young's modulus E by the cross-sectional area A per width of the deck plate and dividing it by the deck length typically used in buildings (for example, beam center distance L = 3000 mm).

[0046] The positions of the second junctions that will be changed are shown in Table 1. The model names in Table 1 are expressed in the format "number of second junctions (position of second junctions)." For example, if there are two second junctions out of 13 junctions and the positions of the second junctions are N1 and N7, the model name will be "2(N1,N7)." In addition, the model name will be "0" if no second junctions are provided (all first junctions), "1(N1)-1(N13)" if one second junction is provided, and "2(N2,N12)..." if two second junctions are provided.

[0047] [Table 1]

[0048] [Analysis results] Figure 14 is a graph of the analysis results. In the graph, the horizontal axis is the position of the second joint from the end of the beam (Lr) / beam length (L), and the vertical axis is the eigenvalue: elastic buckling load eMcr (kNm). Note that in the graph, for "1(N1) to 1(N13)," which have one second joint, the eigenvalue: elastic buckling load versus Lr / L is shown as a line graph, while for "2(N2, N12)..."), which have two second joints, only the eigenvalue: elastic buckling load is shown as a straight line.

[0049] [When one second joint is provided] As shown in Figure 14, in the model (1(N7)) in which the second joint was located at the center of the beam (Lr / L = 0.5, N7) and the models (1(N1), 1(N13)) in which the second joint was located near the end of the beam, the elastic buckling load did not improve (elastic buckling load ≈ 209 kNm) compared to the model (0) in which all joints were the first joints. On the other hand, in the models (1(N4), (1(N10))) in which the second joint was located near Lr / L = 0.25 or Lr / L = 0.75, a tendency for the elastic buckling load to improve was observed (elastic buckling load ≈ 214 kNm).

[0050] [When two second joints are provided] The model (1(N2), 1(N12)) in which the second joint was placed at N2 or N12 had a strength increase of +2.5 kNm against the elastic buckling load compared to model (0) in which all joints were the first. In contrast, the model (2(N2,N12)) in which the second joint was placed at N2 and N12 had a strength increase of +5.3 kNm against the elastic buckling load compared to model (0) in which all joints were the first, more than double the strength increase.

[0051] Furthermore, the increase in strength was small in the model where the second joint was located near the end of the beam (2(N1,N13)) and the model where the second joint was located at the end and center of the beam (2(N1,N7)).On the other hand, the increase in strength was large in the models where the second joint was located near Lr / L = 0.25 and Lr / L = 0.75 (2(N4,N10), 2(N3,N11), 2(N5,N9)).

[0052] [Study on the slenderness ratio of H-shaped steel beams] Next, similar analyses were performed on H-shaped steel beams with different slenderness ratios to examine the differences in analytical results due to the slenderness ratio. The cross-sectional dimensions of the H-shaped steel beams analyzed are shown in Table 2.

[0053] [Table 2]

[0054] Figure 15(a) is a graph of the analysis results for H200 in Table 2. Similarly, Figures 15(b), (c), and (d) are graphs of the analysis results for H250, H350, and H400, respectively. As shown in Figure 15, for H250 (slenderness ratio 83) and H350 (slenderness ratio 58), similar to H300 (slenderness ratio 70), the elastic buckling load improved in the models in which the second joint was located near Lr / L = 0.25 or Lr / L = 0.75. In particular, the elastic buckling load improved in the models in which the second joint was located both near Lr / L = 0.25 and Lr / L = 0.75. Furthermore, for H200 (slenderness ratio 105) and H400 (slenderness ratio 51), the same tendency as for H300 was not observed for the buckling mode, but the elastic buckling load improved in models in which the second joint was located both near Lr / L = 0.25 and near Lr / L = 0.75.

[0055] Based on the above results, the inventors concluded that by placing the second joint at both positions 0.25L±0.1L and 0.75L±0.1L from one end of the H-shaped steel beam 2, the lateral buckling strength of the H-shaped steel beam can be improved regardless of the slenderness ratio.

[0056] Although the present invention relates to a joint structure between a support member and a roof member, it can also be applied without any problems to a joint structure between a support member such as an H-shaped steel beam and a floor member.

[0057] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications or alterations within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention. [Explanation of symbols]

[0058] 1...deck plate, 1A...first deck plate, 11...convex portion, 12...concave portion, 2...H-shaped steel beam, 21A, 21B...flange, 22...web, 3...stud bolt, 4...nut, 5...washer, 6...bearing plate, 61...through hole, 7...weld portion, 9...tight frame, 91...convex portion, 92...concave portion, 100...joint structure, N1 to N13...joint portion.

Claims

1. A joint structure between an H-shaped steel beam which is a supporting member and a roof member, The roof member is joined to the H-shaped steel beam by a first joint portion arranged in the longitudinal direction of the H-shaped steel beam and a second joint portion having higher rigidity than the first joint portion, A roof member joint structure in which the second joint is located at both a position 0.25L±0.1L and a position 0.75L±0.1L from one end of the H-shaped steel beam, where L is the length of the H-shaped steel beam.

2. A joint structure between an H-shaped steel beam which is a supporting member and a roof member, The roof member is joined to the H-shaped steel beam by a first joint portion arranged in the longitudinal direction of the H-shaped steel beam and a second joint portion having higher rigidity than the first joint portion, The roof member is formed by arranging deck plates having one or more uneven shapes so that the extension direction of the uneven shapes is perpendicular to the longitudinal direction of the H-shaped steel beam, and when the length of the H-shaped steel beam is L, first deck plates corresponding to both positions 0.25L±0.1L and 0.75L±0.1L from one end of the H-shaped steel beam have at least one of the second joints.

3. 3. The joining structure of a roof member as described in claim 2, wherein the first deck plate comprises two convex portions, a central recess provided between the convex portions and in the center in the longitudinal direction, and end recesses provided at both ends in the longitudinal direction, and the second joining portion is provided in one of the end recesses of the first deck plate and in the central recess.

4. 3. The joining structure of a roof member as described in claim 2, wherein the first deck plate comprises two convex portions, a central concave portion provided between the convex portions and in the center in the longitudinal direction, and end concave portions provided at both ends in the longitudinal direction, and the second joining portion is provided in both of the end concave portions of the first deck plate.

5. 3. The joining structure of a roof member according to claim 2, wherein the first deck plate comprises two convex portions, a central concave portion provided between the convex portions and in the center in the longitudinal direction, and end concave portions provided at both ends in the longitudinal direction, and the second joining portion is provided in all of the concave portions of the first deck plate.

6. 3. The joining structure of a roof member as described in claim 2, wherein the first deck plate comprises three convex portions, two intermediate concave portions provided between the convex portions, and two end concave portions provided at both ends in the longitudinal direction, and the second joining portion is provided in both the one of the end concave portions of the first deck plate and the intermediate concave portion.

7. 3. The roof member joining structure according to claim 2, wherein the first deck plate comprises three convex portions, two intermediate concave portions provided between the convex portions, and two end concave portions provided at both ends in the longitudinal direction, and the second joining portion is provided in both of the end concave portions of the first deck plate.

8. 3. The joining structure of a roof member according to claim 2, wherein the first deck plate comprises three convex portions, two intermediate concave portions provided between the convex portions, and two end concave portions provided at both ends in the longitudinal direction, and the second joining portion is provided in all of the concave portions of the first deck plate.

9. the first joint is a burn-out plug weld per recess of the deck plate; 9. The joining structure of a roof member according to claim 3, wherein the second joint portion is two burn-off plug welds per recess of the deck plate.

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