Joint structure for channel steel, frame member, panel member, and method for manufacturing the joint structure for channel steel

Abstract

To provide channel steel, a joint structure for channel steel, a frame member, a panel member, a method for manufacturing channel steel, and a method for manufacturing a joint structure for channel steel, which can achieve both a reduction in cross-sectional dimensions and the ensuring of bending resistance while suppressing the burden of joint work.SOLUTION: Channel steel 10 is a long channel steel formed from a single steel plate and having a web 12 and a pair of flanges 14. At least one flange 14 comprises: a strip-shaped base portion 14A continuous with the web 12; a folded portion 14B located at an end of the base portion 14A opposite to the web 12; and a strip-shaped outer layer portion 14C disposed on an outer surface side of the base portion 14A in portions excluding an end in a longitudinal direction L of the flange 14, the outer layer portion 14C extending from the folded portion 14B toward the web 12 alongside the base portion 14A.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a channel steel, a joining structure of channel steels, a frame member, a panel member, a method for manufacturing a channel steel, and a method for manufacturing a joining structure of channel steels.

Background Art

[0002] Conventionally, as a building material, a panel member in which a steel frame member, interior and exterior finishing materials, and functional materials such as a heat insulating material are integrated is known. The panel member is, for example, a building member such as a roofing material or a wall material. As the steel frame member used for the panel member, a long channel steel having a C-shaped cross-sectional shape and having a web and a pair of flanges is often used.

[0003] Specifically, the frame member can be manufactured by, for example, integrating a plurality of channel steels as vertical members extending in the vertical direction and a plurality of channel steels as horizontal members extending in the horizontal direction in a state of intersecting each other by welding, screwing, or the like in a manufacturing factory. Further, for example, a panel member can be constituted by joining a member such as an interior and exterior finishing material or a functional material to the plate surface portion of the flange of the channel steel of the integrated frame member. The manufactured panel member is carried into a construction site of a building and can be attached to the building frame at the construction site.

[0004] Here, since the dimensions of the panel member or the frame member are relatively large, it is required to reduce the burden of on-site work at the construction site where the attachment work is performed. Further, particularly in the construction field, the decrease and aging of skilled workers are becoming problems. For this reason, with regard to the handling of the panel member or the frame member, in order to further reduce the burden of on-site work, miniaturization of the cross-sectional dimensions of the channel steel constituting the frame member is required.

[0005] The cross-sectional dimensions of channel steel can be reduced by shortening at least one of the web height or flange width. However, reducing the cross-sectional dimensions leads to a problem of decreased bending resistance of the channel steel. In other words, achieving both reduced cross-sectional dimensions and sufficient bending resistance is not easy. In this specification, "bending resistance" refers to the performance of the member, including its rigidity and strength against bending.

[0006] Regarding the reduction of cross-sectional dimensions and securing bending resistance, for example, Prior Art Document 1 discloses a light channel steel in which the flange is doubled or more by applying a hemming and folding process to the end of the flange opposite the web. In Prior Art Document 1, the folded portion of the flange is superimposed on the inner surface of the portion of the flange that is continuous with the web. According to the technology of Prior Art Document 1, it is possible to partially increase the cross-sectional area of ​​only the flange portion without including the web portion, and therefore it is possible to obtain a light channel steel with higher cross-sectional properties such as the second moment of area compared to a light channel steel with the same outer diameter.

[0007] Furthermore, prior art 2 discloses a channel steel as a structural steel material in which the end of the flange opposite the web is folded over and overlapped onto the outer surface of the portion continuous with the web of the flange, thereby making the thickness of the flange portion twice that of the web. The overlapping portion continuous with the web of the flange and the folded portion are joined by welding.

[0008] In prior art 2, the total thickness of the flange is (number of folds + 1) times the thickness of the web. For example, if there is one fold, the total thickness of the flange is twice the thickness of the web. According to the technology in prior art 2, by overlapping the flange plates, a flange with a thickness greater than the web can be manufactured from a single steel plate without requiring two types of steel plates. This allows for the economical manufacture of structural members such as columns or beams by suppressing the increase in the number of processing steps. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 5382798 [Patent Document 2] Japanese Patent Application Publication No. 2-296952 [Overview of the project] [Problems that the invention aims to solve]

[0010] However, in prior art 1, in order to join the outer flange surface of the light channel steel with the outer flange surface of the central part of the channel steel positioned perpendicular to the light channel steel, it becomes necessary to narrow the end of the perpendicularly positioned channel steel by the thickness of the inner layer of the double flange of the light channel steel. Therefore, additional work such as drawing is required on the ends of the perpendicularly positioned members, such as the channel steel.

[0011] Furthermore, for example, when the flanges of a channel steel are doubled by hemming bending, if the accuracy of the hemming bending is low, there is a concern that a bulge may occur at the boundary of the folded flange, especially when the plate thickness is large or when high-strength steel plates or other steel plates with high springback are used. Alternatively, there is a concern that a gap may form between the plate portions of the folded flange. As a result, a step may occur between the flange surfaces of the channel steel and the member positioned perpendicular to the channel steel at the joint, resulting in uneven flange surfaces. Therefore, after the hemming bending work, additional adjustment work, such as surface processing, may be required.

[0012] Furthermore, in the case of channel steel described in prior art 2, the folding process is applied over the entire length, resulting in a larger total plate thickness of the flange over the entire length. Therefore, when joining other structural members to the folded portion of the flange, greater pressure is required when inserting the joint due to the increased thickness. As a result, the burden of the joining work increases. In addition, prior art 2 is used to manufacture structural members with relatively high strength, such as columns or beams, which also involves the burden of welding the portion of the overlapping flange that is continuous with the web to the folded portion.

[0013] In view of the above-mentioned problems, this disclosure aims to provide channel steel, a channel steel joining structure, a frame member, a panel member, a method for manufacturing channel steel, and a method for manufacturing a channel steel joining structure, which can achieve both miniaturization of cross-sectional dimensions and securing bending resistance while suppressing the burden of joining work. [Means for solving the problem]

[0014] A channel steel according to a first aspect of the present disclosure is a long channel steel formed from a single steel plate and having a web and a pair of flanges, wherein at least one flange comprises a strip-shaped base continuous with the web, a folded portion located at the end of the base opposite to the web, and a strip-shaped outer layer portion disposed on the outer surface side of the base in the portion of the flange excluding the longitudinal end, and extending parallel to the base from the folded portion toward the web.

[0015] In the channel steel according to the first embodiment, the outer surface of the base is exposed at the longitudinal end of the flange because the outer layer is not positioned on the outer surface side of the base. The longitudinal end of the flange functions as a joint with other structural members. For example, by preparing another channel steel and joining the flange of the prepared other channel steel to the outer surface of the base at its end, a joint structure in which two channel steels are joined can be obtained. That is, in the joint structure, the plate thickness of the flange is not increased at the end where the joint is formed, so the burden of the joining work can be reduced compared to the case where the plate thickness at the end where the joint is formed is increased, for example, by folding a part of the flange.

[0016] Furthermore, in the first embodiment, in the portion of the flange excluding the longitudinal end, the outer layer, which is the portion folded back toward the web side, is arranged on the outer surface of the base in a parallel manner. Therefore, the thickness of the portion of the channel steel excluding the end that has the outer layer is greater than the thickness of the end that does not have the outer layer. For example, if the channel steel is formed from a single steel plate of substantially uniform thickness, the flange thickness in the portion excluding the end that has the outer layer can be increased to twice the flange thickness at the end that consists only of the base.

[0017] In other words, in the portion of the channel steel excluding the ends, the steel material is concentrated at the flange, which is the outer edge of the cross-section that is effective in improving bending resistance. Therefore, even if the cross-sectional dimensions are reduced, the bending resistance per unit weight can be strengthened compared to channel steel without an outer layer. In other words, the outer layer in the portion excluding the ends reinforces the bending resistance so that it does not decrease due to the reduction in cross-sectional dimensions.

[0018] Therefore, according to the channel steel of the first embodiment, it is possible to provide channel steel that can achieve both miniaturization of cross-sectional dimensions and securing bending resistance while suppressing the burden of joining work.

[0019] Furthermore, the joint structure for channel steel according to a second aspect of the present disclosure is a joint structure in which a long first channel steel formed from a single steel plate and having a web and a pair of flanges and a long second channel steel formed from a steel plate other than the first steel plate and having a web and a pair of flanges are joined together with their respective longitudinal directions perpendicular to each other, wherein the pair of flanges of the first channel steel comprises a strip-shaped base continuous with the web, a folded portion located at the end of the base opposite to the web, and a strip-shaped outer layer portion arranged on the outer surface side of the base in the portion of the flange excluding the longitudinal end, and extending parallel to the base from the folded portion toward the web, and the pair of flanges of the second channel steel are joined onto the outer surfaces of the respective bases at the longitudinal ends of the pair of flanges of the first channel steel.

[0020] In the channel steel joint structure according to the second embodiment, the first channel steel, which is configured in the same way as the channel steel of the first embodiment, is joined to the second channel steel. This provides a joint structure that can reduce the burden of joining work while simultaneously achieving both a smaller cross-sectional size and sufficient bending resistance.

[0021] A frame member according to a third aspect of the present disclosure comprises a pair of vertical members arranged parallel to each other with space between them, including a long first channel steel formed from a single steel plate and having a web and a pair of flanges, and a pair of horizontal members formed from a steel plate separate from the first steel plate and having a long second channel steel formed from a single steel plate and having a web and a pair of flanges, the horizontal members joined at one end and the other end of the pair of vertical members in such a state that their longitudinal direction is perpendicular to the longitudinal direction of the vertical members, and a channel steel joint structure according to the second aspect is formed at at least one of the joints between the vertical members and the horizontal members.

[0022] The frame member according to the third embodiment includes a joint structure in which a first channel steel, which can achieve both a smaller cross-sectional dimension and sufficient bending resistance while suppressing the burden of joining work, is joined to a second channel steel, similar to the first embodiment. Therefore, in the third embodiment, it is possible to achieve both a smaller cross-sectional dimension of the frame member itself and sufficient bending resistance.

[0023] A panel member according to a fourth aspect of the present disclosure comprises a frame member according to a third aspect and a surface material provided on the frame member.

[0024] The panel member according to the fourth aspect includes a frame member in which a first channel steel capable of achieving both miniaturization of the cross-sectional dimension and ensuring bending resistance while suppressing the burden of joining work is joined to a second channel steel, as in the case of the first aspect. Therefore, in the fourth aspect, it is possible to achieve both miniaturization of the cross-sectional dimension of the panel member itself and ensuring bending resistance. Further, as the frame member is miniaturized or lightened, it is easier to add members other than the frame member to the panel member. Thus, the functions of the facing material can be diversified. In addition, it is possible to improve the transportation efficiency of the panel member, that is, to improve logistics, and to improve the on-site workability of the panel member.

[0025] The manufacturing method of channel steel according to the fifth aspect of the present disclosure is a manufacturing method of a long channel steel having a web and a pair of flanges. In a single steel plate having a web planned area for forming the web and flange planned areas for forming the pair of flanges, when at least one of the flange planned areas is divided into a strip-shaped base planned area continuous with the web planned area and a strip-shaped outer layer part planned area located on the opposite side of the web planned area from the base planned area, the step of removing the longitudinal end portions of the outer layer part planned area in the steel plate; the step of folding back the outer layer part planned area toward the web planned area side, disposing the folded outer layer part planned area as an outer layer part above the base planned area, and forming the base planned area with the outer layer part disposed above as a base; and the step of bending the base to be orthogonal to the web planned area by bending it to the opposite side of the outer layer part, thereby forming the web planned area as the web of the channel steel and forming the base and the outer layer part as the flanges of the channel steel.

[0026] In the manufacturing method of channel steel according to the fifth aspect, as in the case of the first aspect, it is possible to manufacture channel steel capable of achieving both miniaturization of the cross-sectional dimension and ensuring bending resistance while suppressing the burden of joining work.

[0027] Furthermore, in the fifth embodiment, when a bending moment generated by an out-of-plane external force is received by the channel steel, the base and the outer layer are in close contact throughout. Due to this close contact, in the section where the bending moment occurs, i.e., the entire region in the flange where compressive and tensile stresses are distributed along the material axis, the base and the outer layer resist the bending moment while mutually constraining each other in the out-of-plane direction, thus suppressing buckling due to the compressive stress. In addition, within the flange, the outer layer is partially compressed as a result of the direct action of the out-of-plane external force itself. Since the action of the external force is added in this compressed portion, the mutual restraint between the base and the outer layer generated by the action of the bending moment is further locally enhanced. As a result, the effect of suppressing buckling by mutual restraint can be increased, eliminating the need to pre-integrate the base and the outer layer by welding or the like.

[0028] A method for manufacturing a channel steel joint structure according to a sixth aspect of this disclosure is a method for manufacturing a channel steel joint structure in which a long channel steel, formed from a single steel plate and having a web and a pair of flanges, and a long channel steel, formed from a steel plate other than the single steel plate and having a web and a pair of flanges, are joined together with their respective longitudinal directions perpendicular to each other, wherein the pair of flanges of the second channel steel are joined onto the outer surfaces of the bases of the pair of flanges of the first channel steel, which are manufactured using the method for manufacturing channel steel according to a fifth aspect.

[0029] In the manufacturing method for a channel steel joint structure according to the sixth embodiment, similar to the second embodiment, a channel steel joint structure can be realized that achieves both miniaturization of cross-sectional dimensions and securing bending resistance while suppressing the burden of joining work. [Effects of the Invention]

[0030] According to this disclosure, it is possible to provide channel steel, a channel steel joining structure, a frame member, a panel member, a method for manufacturing channel steel, and a method for manufacturing a channel steel joining structure, which can achieve both miniaturization of cross-sectional dimensions and securing bending resistance while suppressing the burden of joining work. [Brief explanation of the drawing]

[0031] [Figure 1] This is a perspective view illustrating a channel steel according to an embodiment of the present disclosure. [Figure 2] This is a side view of the channel steel according to this embodiment, viewed along its longitudinal direction. [Figure 3] Figure 3(A) is a side view of a channel steel having an outer layer according to the first modified example, and Figure 3(B) is a side view of a channel steel having an outer layer according to the second modified example. [Figure 4] Figure 4(A) is a side view of a channel steel having an outer layer according to the third modified example, and Figure 4(B) is a side view of a channel steel having an outer layer according to the fourth modified example. [Figure 5] This is a side view of a channel steel having an outer layer according to the fifth modified example. [Figure 6] This figure (1) illustrates the method for manufacturing channel steel according to this embodiment, showing the surface of the steel plate, which is the material for the channel steel, viewed from the front. [Figure 7] This is a side view illustrating the manufacturing method of channel steel according to this embodiment (part 2). [Figure 8] This is a front view illustrating a frame member in which the channel steel according to this embodiment is used as the first channel steel. [Figure 9] This is an enlarged view of one corner of the frame member in Figure 8, where the channel steel joint structure according to this embodiment is formed. [Figure 10] This diagram illustrates one corner of the frame member in Figure 8, showing the front view of the web surface of the first channel steel. [Figure 11] This is a cross-sectional view taken along line 11-11 in Figure 9. [Figure 12] This is a cross-sectional view of a panel member according to this embodiment, in which a facing material is provided on a frame member, when cut at the same position as the cross-sectional view in Figure 11. [Figure 13] This is a perspective view illustrating the manufacturing method of the channel steel joint structure according to this embodiment. [Figure 14]Figure 14(A) is a side view illustrating the channel steel according to this embodiment when it is bent from the flange side along the web surface, and Figure 14(B) is a side view schematically illustrating the behavior of the channel steel according to this embodiment when it is bent. [Figure 15] Figure 15(A) is a side view illustrating a channel steel in a comparative example where bending is applied from the flange side along the web surface, and Figure 15(B) is a side view schematically illustrating the behavior of the channel steel in the comparative example when bending is applied. [Figure 16] This is a cross-sectional view of the frame member relating to the first comparative example, obtained by cutting it at the same position as the cross-sectional view in Figure 11. [Figure 17] This figure illustrates the method of an equal bending test performed using channel steel according to this embodiment, showing the web surface of the channel steel specimen, which has a test section where equal bending is performed and a stiffened portion outside the test section, as viewed from the front. [Figure 18] This is a photograph of a channel steel section that has undergone localized buckling in its outer layer during an equibending test. [Figure 19] This graph illustrates the results of the equal bending test. [Figure 20] This figure illustrates the bending shear test method performed on the joint structure of the channel steel according to this embodiment, as viewed from the front of the outer layer plate surface of the first channel steel. [Figure 21] Figure 21(A) is a photograph illustrating the final state of the joint of the joint structure according to the embodiment after failure by a bending shear test, and Figure 21(B) is a photograph illustrating the final state of the joint of the joint structure according to the second comparative example. [Figure 22] This graph illustrates the results of a bending shear test. [Modes for carrying out the invention]

[0032] Embodiments of the present disclosure are described below. In the following drawings, identical and similar parts are denoted by the same or similar reference numerals. However, the relationship between thickness and planar dimensions, the ratio of thickness of each device and component, etc., in the drawings differ from those in reality. Therefore, specific thicknesses and dimensions should be determined by referring to the following explanation. Furthermore, there are parts where the relationships and ratios of dimensions differ between drawings.

[0033] <Channel steel> First, the channel steel according to this embodiment will be described with reference to Figures 1 to 4. As shown in Figure 1, the channel steel 10 according to this embodiment is a long channel steel 10 formed from a single steel plate and having a web 12 and a pair of flanges 14. Specifically, the channel steel 10 can be formed by bending a single steel plate using a roll forming device or a bending device.

[0034] Each of the pair of flanges 14 of the channel steel 10 comprises a base portion 14A, a folded portion 14B located at the end of the base portion 14A opposite to the web 12, and an outer layer portion 14C. However, in this disclosure, it is not essential that both flanges of the channel steel comprise the base portion, the folded portion, and the outer layer portion. In this disclosure, it is sufficient that at least one flange comprises the base portion, the folded portion, and the outer layer portion.

[0035] In this embodiment, the pair of flanges 14 are configured symmetrically across a horizontal center line C passing through the web 12 in Figure 2. Therefore, the configuration of the upper flange 14 in Figure 2 is the same as the configuration of the lower flange 14. Accordingly, in this specification, only the base portion 14A, the folded portion 14B, and the outer layer portion 14C of one flange 14 will be described in detail, and redundant descriptions of the other flange 14 will be omitted.

[0036] (base) The base portion 14A is a strip-shaped, flat portion that is continuous with the web 12 on each of the pair of flanges 14. The outer surface of the base portion 14A is exposed at the end in the longitudinal direction L1, as shown in Figure 1. In this specification, the "longitudinal direction of the channel steel" means the direction that is perpendicular to the opposing direction of the pair of flanges 14 (the vertical direction in Figure 1) and extends parallel to the plate surface of the web 12 (the direction that extends between the lower left and upper right in Figure 1).

[0037] (outer layer) As shown in Figure 1, the outer layer portion 14C is located on the outer surface side of the base portion 14A in the portion of the flange 14 excluding the end in the longitudinal direction L1. The outer layer portion 14C is a flat, strip-shaped portion of the flange 14 that is continuous with the folded portion 14B and extends from the folded portion 14B toward the web 12, alongside the base portion 14A.

[0038] In this embodiment, an example was given in which the outer layer portion 14C is not located at either end in the longitudinal direction L1, but this disclosure is not limited to this. In this disclosure, the outer layer portion may be located at one end of the longitudinal direction, while the outer layer portion may not be located at the other end. Also, "outer surface side of the base portion 14A" means the side opposite to the opening 16 of the channel steel 10.

[0039] In this embodiment, the length of the longitudinal direction L1 can be set to, for example, approximately 2800 mm to approximately 3000 mm. Also, the flange width WF measured along the horizontal left-right direction in Figure 2 can be set to approximately 33 mm, the web height HW measured along the vertical up-down direction in Figure 2 can be set to approximately 60 mm, and the plate thickness of the channel steel 10 can be set to approximately 1.2 mm. In other words, the channel steel 10 according to this embodiment is a so-called lightweight channel steel formed from thin plate. It should be noted that in this disclosure, the channel steel is not limited to thin-plate lightweight structural steel, but may be structural steel having any plate thickness.

[0040] In this embodiment, the "web-direction height HW" is one of the dimension elements that define the outer edge of the rectangular cross-sectional shape of the channel steel, and corresponds to the "web height" in a general channel steel that does not have an outer layer. Furthermore, in this disclosure, the longitudinal length, flange width, web-direction height, and plate thickness can be changed as appropriate.

[0041] Here, the aspect ratio of the web 12 when viewed from the front is defined by (length in the longitudinal direction L1) / (height in the web direction HW). In this embodiment, the aspect ratio of the channel steel 10 can be set to, for example, 4 to 5 times. Specifically, for example, if the height in the web direction HW is about 60 mm to 75 mm, the length in the longitudinal direction L1 can be set to about 300 mm. In this embodiment, "long-shaped" means that the aspect ratio of the channel steel is 4 times or more. Note that in this disclosure, the aspect ratio is not limited to 4 to 5 times, but can be set to any value.

[0042] In this embodiment, the length from the right end of the folded portion 14B to the left end of the outer layer portion 14C, measured along the left-right direction in Figure 2, is described as the "width WC of the outer layer portion 14C". It is preferable that the width WC of the outer layer portion 14C be set to 50% or more and 100% or less of the flange width WF. If the width WC of the outer layer portion 14C is less than 50% of the flange width WF, it is difficult to ensure the bending resistance of the channel steel 10. Also, if the width WC of the outer layer portion 14C exceeds 100% of the flange width WF, it is easy to hinder the miniaturization of the channel steel 10, and it is difficult to manufacture the channel steel 10.

[0043] In this embodiment, the width WC of the outer layer 14C is approximately 90% of the flange width WF. In addition, in this disclosure, the width WC of the outer layer 14C can be set arbitrarily.

[0044] (Another example of the outer layer: First variation) In this embodiment, an example is shown in which the outer layer portion 14C is superimposed on the outer surface of the base portion 14A to form an outer layer portion 14C positioned on the outer surface side of the base portion 14A; however, this disclosure is not limited thereto. In this disclosure, for example, the outer layer portion 14C may be positioned substantially parallel to the base portion 14A with a small gap G between them, as shown in the first modified example illustrated in Figure 3(A). From the viewpoint of ensuring accuracy during assembly of the structure, it is preferable that the width of the gap G measured along the vertical direction in Figure 3(A) be at least 1.5 mm or less.

[0045] If the width of the gap G exceeds 1.5 mm, the variation in the height direction (web height direction) becomes large, making it difficult to ensure accuracy when manufacturing the structure by assembling the channel steel 10. Furthermore, it is more preferable from the viewpoint of ensuring accuracy if the width of the gap G is 1.0 mm or less.

[0046] The outer layer portion 14C of the first modified example is included in the “outer layer portion arranged on the outer surface side of the base portion” of this disclosure. Even if the outer layer portion 14C is arranged substantially parallel to the base portion 14A with a small gap G between them, it is possible to achieve both a reduction in the cross-sectional dimensions of the channel steel 10 and securing bending resistance.

[0047] (Another example of the outer layer: Second variation) Furthermore, in this disclosure, as shown in the second modified example illustrated in Figure 3(B), the folded portion 14B may extend toward the opening 16 side of the channel steel 10, thereby protruding toward the opening 16 side. The protruding folded portion 14B can function in the channel steel 10 like the lip portion of a so-called lip channel steel. In the case of the channel steel 10 illustrated in Figure 3(B), the joint with other structural members is formed at the end of the portion where the outer layer 14C is not located, so even if the folded portion 14B protrudes, no step difference is created between the outer surface of the outer layer 14C and the outer surface of the flange of the other structural member.

[0048] In other words, when the plate thickness is large or when high-strength steel plates or other steel plates with high springback are used, a bulge may occur in the folded portion 14B of the flange 14, for example, due to low accuracy in hemming bending. However, by applying the configuration of the second modified example, it is possible to avoid the occurrence of a step between the outer surface of the outer layer portion 14C and the outer surface of the flange of other structural members.

[0049] The outer layer portion 14C according to the second modified example is included in the “outer layer portion disposed on the outer surface side of the base portion” of this disclosure. Even if the outer layer portion 14C is in partial contact with the base portion 14A, it is possible to achieve both a reduction in the cross-sectional dimensions of the channel steel 10 and securing bending resistance.

[0050] Furthermore, although this embodiment illustrates a case where the outer layer 14C is folded back at approximately 180 degrees, this disclosure is not limited to this. As can be seen from the state of the outer layer 14C in Figure 3(B), the folding angle may be other than 180 degrees and can be changed as appropriate.

[0051] (Another example of the outer layer: Third variation) In this embodiment, a case in which one outer layer 14C is superimposed on the outer surface of the base 14A is illustrated, but the disclosure is not limited thereto. In this disclosure, multiple outer layers 14C may be superimposed on the outer surface of the base 14A. In the third modification shown in Figure 4(A), a case in which two outer layers 14C are superimposed on the outer surface of the base 14A is illustrated. According to the third modification, the total plate thickness of the flange 14 is increased compared to the case in which there is one outer layer 14C, so the bending resistance can be further strengthened.

[0052] (Another example of the outer layer: Fourth variation) Furthermore, as illustrated in the fourth modified example in Figure 4(B), the tip region of the outer layer 14C on the side opposite to the folded portion 14B (the left side in Figure 4(B)) may extend beyond the web 12 to the outside of the channel steel 10 (the left side in Figure 4(B)). By extending the tip region of the outer layer 14C beyond the web 12, the area of ​​the portion that can be used for joining with other building members can be increased, for example.

[0053] (Another example of the outer layer: Modification 5) Furthermore, as illustrated in the fifth modified example in Figure 5, the portion of the outer layer 14C that extends beyond the web 12 on the opposite side of the folded portion 14B (the left side in Figure 5) is bent approximately 90 degrees along the plate surface of the web 12. In addition, the inner surface of the bent tip portion of the outer layer 14C is in contact with the outer surface of the web 12.

[0054] In this case, if there is only one outer layer 14C superimposed on the outer surface of the base 14A, the outer layer 14C may float beyond the design range from the base 14A, that is, it may separate from the base 14A. In the fifth modified example, the floating state of the outer layer 14C can be suppressed by using the frictional resistance of the contact surface between the outer surface of the web 12 and the tip of the outer layer 14C, so that the floating state of the outer layer 14C becomes less noticeable in appearance.

[0055] <Manufacturing method for channel steel> Next, the method for manufacturing channel steel according to this embodiment will be described with reference to Figures 6 and 7. In this embodiment, the case in which channel steel 10 is manufactured by bending a single steel plate 100, which is the raw material, will be described as an example.

[0056] As shown in Figure 6, first, a single rectangular steel plate 100 is prepared in plan view, and this single steel plate 100 is divided into one planned web area 120 and two planned flange areas 140 located at both the left and right ends of the planned web area 120. The planned web area 120 forms the web 12 when the steel plate 100 is formed into the channel steel 10. The two planned flange areas 140 form a pair of flanges 14 when the steel plate 100 is formed into the channel steel 10.

[0057] Furthermore, in a single steel sheet 100, the two planned flange regions 140 are divided into a strip-shaped planned base region 140A that is continuous with the planned web region 120, and a strip-shaped planned outer layer region 140C located on the opposite side of the planned web region 120 from the planned web region 120. The boundary region between the planned base region 140A and the planned outer layer region 140C is divided as the planned bending region 140B. In this disclosure, it is sufficient that at least one of the two planned flange regions in a single steel sheet is divided into a planned base region and a planned outer layer region.

[0058] Next, the longitudinal end L1 of the planned outer layer area 140C of the steel plate 100 is removed using a cutting device or the like. In Figure 6, the four planned removal areas X located at the four corners of the steel plate 100 are illustrated with diagonal rectangular areas for clarity.

[0059] Next, as shown in Figure 7, the two outer layer areas 140C on the left and right are folded back towards the web area 120 along the planned folding area 140B. In Figure 7, the outer layer areas 140C before folding are shown as dotted lines, and the folded outer layer areas 140C after folding are shown as solid lines. The folded outer layer areas 140C are positioned as outer layers on the upper side of the planned base area 140A. The planned base area 140A, with the outer layers positioned on the upper side, is formed as the base.

[0060] Next, the base area 140A, with the outer layer area 140C positioned above it, is folded to the opposite side of the outer layer area 140C, i.e., to the web side (the center side in the left-right direction in Figure 7), thereby making it perpendicular to the web area 120. In Figure 7, the base area 140A and outer layer area 140C after folding are illustrated by a dashed line.

[0061] By bending perpendicularly, the planned web area 120 is formed as the web 12 of the channel steel 10 in Figure 1. The planned base area 140A is formed as the base 14A of the flange 14 of the channel steel 10 in Figure 1. The planned bent portion area 140B is formed as the folded portion 14B of the flange 14 of the channel steel 10 in Figure 1. The planned outer layer area 140C is formed as the outer layer 14C of the flange 14 of the channel steel 10 in Figure 1. Through the above series of steps, the channel steel 10 according to this embodiment can be obtained.

[0062] In this disclosure, after removing four planned removal areas X from a single steel plate 100, the channel steel 10 may first be formed by bending the steel plate 100 at approximately 90 degrees at the boundary between the planned web area 120 and the planned base area 140A. Then, the outer layer area 14C can be formed by bending the steel plate 100 at approximately 180 degrees along the planned bending area 140B.

[0063] Furthermore, in this disclosure, a structural steel section may be formed, for example, by roll forming, first, having a C-shaped outer diameter and a flange in which the planned outer layer region 140C is superimposed over the entire length, including the end in the longitudinal direction L1. In other words, a structural steel section with a C-shaped cross-section is formed without removing the planned removal region X.

[0064] Alternatively, a channel steel section 10 having an outer layer 14C may be manufactured by partially removing portions corresponding to the areas to be removed X from the outer layer sections 140C at each of the four ends of the formed steel section in the longitudinal direction L1, using a cutting device or the like. However, if the four areas to be removed X are removed first using a cutting device or the like, the workload may increase, such as requiring high accuracy in alignment during cutting. For this reason, the method of first removing the four areas to be removed X from a single steel plate 100 and then forming the steel plate 100 is more likely to reduce overall manufacturing costs.

[0065] <Joining structure of channel steel> Next, the joint structure of the channel steel according to this embodiment will be described with reference to Figures 8 to 12.

[0066] (Frame component) As shown in Figure 8, the frame member 300 according to this embodiment has a pair of vertical members 310 and a pair of horizontal members 320. The pair of vertical members 310 are positioned at both ends in the left-right direction in Figure 8 and extend along the vertical direction. In this embodiment, in addition to the pair of vertical members 310 of this disclosure, a pair of vertical members 310 is also secondarily positioned in the center in the left-right direction in Figure 8. It should be noted that the secondary arrangement of vertical members 310 is not mandatory in this disclosure. Furthermore, the number of secondary vertical members 310 is not limited to one, but may be two or more, and can be set arbitrarily.

[0067] Furthermore, a pair of horizontal members 320 are positioned at both ends in the vertical direction in Figure 8. The frame portion of the frame member 300 is formed by a pair of vertical members 310 and a pair of horizontal members 320. In this disclosure, a pair of vertical members does not need to be positioned at both ends in the direction of arrangement of the pair of vertical members; one or two vertical members of a pair may be positioned at a certain distance from the end towards the center in the direction of arrangement, as long as they can constitute a frame member. Similarly, in this disclosure, a pair of horizontal members does not need to be positioned at both ends in the direction of arrangement of the pair of horizontal members; one or two horizontal members of a pair may be positioned at a certain distance from the end towards the center in the direction of arrangement.

[0068] (Vertical members) The vertical members 310 at both the left and right ends in Figure 8, and the secondary vertical member 310 positioned in the center, are arranged parallel to each other with space between them. The channel steel 10 exemplified in Figure 1 is used as the vertical member 310. The vertical member 310 constitutes the first channel steel of this disclosure. In this disclosure, members other than the first channel steel may be attached to the vertical member 310, and the vertical member 310 is not limited to the first channel steel.

[0069] In this embodiment, the following examples illustrate the case where the first channel steel is used for the vertical member 310 and the second channel steel is used for the horizontal member 320. However, in this disclosure, the first channel steel may be used for the horizontal member and the second channel steel may be used for the vertical member. In this disclosure, when one first channel steel and one second channel steel are used, there is no limitation on whether each channel steel is placed in the vertical member or the horizontal member.

[0070] (Horizontal material) A pair of crossbars 320 are formed from a separate steel plate 100 from the steel plate 100 used for the first channel steel, and have a web 12 and a pair of flanges 14. The crossbars 320 constitute the second channel steel of this disclosure. In this disclosure, the crossbars 320, like the longitudinal members 310, may have members other than the second channel steel attached to them, and are not limited to the second channel steel.

[0071] The horizontal members 320 are joined to the vertical members 310 at each of their respective ends (e.g., the upper end in Figure 8 and the lower end in Figure 8), such that the longitudinal direction L2 of the horizontal member 320 is perpendicular to the longitudinal direction L1 of the vertical member 310. In this disclosure, it is sufficient that at least one pair of horizontal members 320 are joined to a pair of vertical members 310 at each of their respective ends, such that the longitudinal direction L2 of the horizontal member 320 is perpendicular to the longitudinal direction L1 of the vertical member 310.

[0072] In this embodiment, both the steel plate 100 constituting the first channel steel as the vertical member 310 and the other steel plate 100 constituting the second channel steel as the horizontal member 320 are pre-plated steel plates, i.e., pre-plated steel plates. In this disclosure, it is sufficient that at least one of the steel plate 100 and the other steel plate 100 is a plated steel plate.

[0073] (joint structure) Next, the channel steel joint structure according to this embodiment will be described in detail. In this embodiment, as shown in Figure 8, the channel steel joint structure is formed at all six joints between the vertical members 310 and the horizontal members 320. For this reason, in the following description, the joint corresponding to the lower left corner A in Figure 8 will be used as a representative example. In this disclosure, it is not necessary to form a channel steel joint structure similar to corner A in Figure 8 at all joints between the vertical members and the horizontal members; it is sufficient to form it at least at one.

[0074] As shown in Figure 9, in the channel steel joint structure, a longitudinal member 310, which is a long first channel steel, and a transverse member 320, which is a long second channel steel, are joined together with the longitudinal direction L1 of the longitudinal member 310 and the longitudinal direction L2 of the transverse member 320 being perpendicular to each other.

[0075] In this embodiment, as shown in Figure 9, an example was given where the vertical member 310 as the first channel steel and the horizontal member 320 as the second channel steel are orthogonal, and the intersection angle between the flat web 312 surface of the vertical member 310 and the flat web 322 surface of the horizontal member 320 is 90 degrees. However, in this disclosure, "orthogonal" is not limited to cases where the intersection angle is strictly 90 degrees. If the intersection angle between the flat web surface of the vertical member and the flat web surface of the horizontal member is 85 degrees or more and 95 degrees or less, it can be considered "orthogonal".

[0076] As shown in Figures 10 and 11, in this embodiment, the pair of flanges 324 of the horizontal member 320, which is the second channel steel, are joined to the outer surfaces of the respective bases 314A at the longitudinal ends L1 of the pair of flanges 314 of the vertical member 310, which is the first channel steel.

[0077] In this embodiment, the thickness of the base portion 314A of the flange 314 of the vertical member 310 and the thickness of the flange 324 of the horizontal member 320 are the same. Furthermore, in the vertical member 310 formed from a single steel plate, the thickness of the outer layer portion 314C of the flange 314 and the thickness of the base portion 314A are the same. Therefore, as shown in Figure 10, the outer surface of the outer layer portion 314C of the flange 314 of the vertical member 310 and the outer surface of the flange 324 of the horizontal member 320 are flush in the vertical direction. As a result, in the channel steel joint structure according to this embodiment, there is no unevenness on the outer surface of the joint. Note that in this disclosure, the thickness of the base portion of the flange of the vertical member and the thickness of the flange of the horizontal member may be different from each other.

[0078] (Joint tool) In this embodiment, the joining method between the base 314A of the flange 314 of the vertical member 310, which is the first channel steel, and the flange 324 of the horizontal member 320, which is the second channel steel, is a dry joining using a fastener 30. Specifically, two screws are used as the fastener 30 for the base 314A of one flange 314.

[0079] In this embodiment, the number of screw fastening positions for the fastener 30 is exemplified as two for the base 14A of one flange 14, but the number of fastening positions is not limited to this in this disclosure. In this disclosure, the number of fastening positions for the base 14A of one flange 14 may be one, or two or more, or any other number, depending on the fastening method.

[0080] Furthermore, while this embodiment exemplifies a method of dry joining using screws as the fastener 30, this disclosure is not limited to this. This disclosure may also use other dry joining fasteners, such as bolts and nuts. In addition, this disclosure may also form a joint structure by "crimping". Moreover, this disclosure is not limited to dry joining as the joining method, and may also use wet joining.

[0081] As shown in Figure 11, when screws are driven in the same straight line into each of the opposing flanges 14 in the left-right direction from which the screws of the fastener 30 extend, the screws are arranged so that they do not overlap when viewed from the front, as shown in Figure 9.

[0082] For example, the dashed line V1 in Figure 9 is a line drawn with one dot, connecting the centers of the screw heads of the two fasteners 30 that appear in a circular shape on the front side of the page in Figure 9. Similarly, the dashed line V2 in Figure 9 is a line drawn with two dots, connecting the centers of the screw heads of the two fasteners 30 that appear in a circular shape on the back side of the page in Figure 9. The screws driven into each of the opposing flanges 14 are positioned so that the dashed lines V1 and V2 intersect.

[0083] Furthermore, for example, the protrusion of the screw heads may be suppressed by forming an area on the outer surface of the flange 324 of the horizontal member 320, around the planned placement position of the screws of the fastener 30, by embossing or the like, to reduce the surface height. By suppressing the protrusion of the screw heads, the outer surface of the flange 324 of the horizontal member 320 and the outer surface of the outer layer portion 314C of the flange 314 of the vertical member 310 can be made even more flush.

[0084] Furthermore, in addition to joining only the flange 314 of the vertical member 310 and the flange 324 of the horizontal member 320, it is also possible to integrate the flange 314 of the vertical member 310, the flange 324 of the horizontal member 320, and the facing material 40, as shown in Figure 12. By providing the facing material 40 to the frame member 300 according to this embodiment, a panel member 400 comprising the frame member 300 and the facing material 40 can be realized.

[0085] Furthermore, as shown in Figure 12, when one or more members are integrated into the frame member 300 using, for example, screws, it is preferable to pre-form through holes in the flange 314 of the vertical member 310 and the flange 324 of the horizontal member 320 to reduce the burden when driving screws.

[0086] Furthermore, as shown in Figure 12, when fasteners 30 such as screws are driven in from the opening 16 on the inside of the joint, such as when fastening fasteners 30 are driven in from the opening 16 on the inside of the joint, it may be difficult to secure sufficient space for the driving work. In other words, since a rod-shaped tool such as a screwdriver is required for the driving work, it may be possible to perform the work only from the outside of the joint.

[0087] Therefore, for example, through holes TH1 and TH2 are formed in advance as tool holes along the thickness direction, such as the through holes TH1 and TH2 provided in the base 314A of the vertical member 310 and the flange 324 of the horizontal member 320, which are located on the right side in Figure 12. When the vertical member 310 and the horizontal member 320 are overlapped and aligned, the through hole TH1 in the base 314A of the vertical member 310 and the through hole TH2 in the flange 324 of the horizontal member 320 function as a single tool hole when the plate surface of the flange 324 of the horizontal member 320 is viewed from the front.

[0088] Furthermore, although not shown in the diagram, a second tool hole is formed in the base 314A of the vertical member 310 and the flange 324 of the horizontal member 320, in addition to the first tool hole composed of through holes TH1 and TH2. The second tool hole can be formed in the same way as the first tool hole, for example, at a position corresponding to the center of the screw head in the lower left of the dashed line V2 in Figure 9. In other words, a total of two tool holes are arranged on one of the flange sides on the right in Figure 12.

[0089] When viewing the plate surface of the flange 324 of the horizontal member 320 from the front, the imaginary line connecting the centers of the two tool holes (see imaginary line V2 in Figure 9) intersects with the imaginary line connecting the heads of the two screws of the fastener 30 located on the right side in Figure 12 (see imaginary line V1 in Figure 9). Then, at the construction site, by overlapping and aligning the vertical member 310 and the horizontal member 320, two tool holes are formed at the joint between the right vertical member 310 and the horizontal member 320, which is one flange side in Figure 12. Then, by inserting a rod-shaped tool such as a screwdriver into the two tool holes and reaching the position of the left joint, which is the other flange side in Figure 12, it becomes possible to drive screws into the left joint from the inner opening 16 side before screwing in the right joint.

[0090] <Manufacturing method for connecting channel steel structures> As a method for manufacturing the channel steel joint structure according to this embodiment, the channel steel 10 according to this embodiment is manufactured as a vertical member 310 by the "Method for Manufacturing Channel Steel" described above with reference to Figures 6 and 7. In addition, a general channel steel without an outer layer is prepared as a horizontal member 320. Next, as shown in Figure 13, the inner surfaces of the pair of flanges 324 of the horizontal member 320 are superimposed on the outer surface of the base portion 314A exposed at the longitudinal end L1 of the pair of flanges 314 of the manufactured vertical member 310.

[0091] In this embodiment, the vertical member 310 and the horizontal member 320 overlap so that the longitudinal direction L1 of the vertical member 310 and the longitudinal direction L2 of the horizontal member 320 are perpendicular to each other. In Figure 13, the joining position 30A corresponding to the position where screws are driven is illustrated by a dotted ellipse within the flange 324 of the horizontal member 320. The flanges 314 of the vertical member 310 and the flanges 324 of the horizontal member 320, which overlap each other, are then joined, for example, by fastening screws. The above series of steps constitutes the manufacturing method of the channel steel joining structure according to this embodiment. [Examples]

[0092] (Behavior of channel steel) Next, the behavior of the channel steel 10 according to the embodiment of this model will be described with reference to Figures 14 and 15. The configuration of the channel steel 10Z according to the first comparative example illustrated in Figure 15 is the same as that of the channel steel 10 according to the embodiment illustrated in Figure 1, in terms of its longitudinal dimensions, web height, and flange width. Furthermore, the channel steel 10Z according to the first comparative example has a base portion 14A and a folded portion 14B, similar to the channel steel 10 according to the embodiment. However, the first comparative example differs from the embodiment in that the portion of the flange 14 that is continuous with the base portion 14A and opposite to the web 12 is superimposed on the inner surface of the base portion 14A on the opening 16 side as an inner layer portion 14Z.

[0093] First, as shown in Figure 14(A), in the channel steel 10 according to the embodiment, consider the case where a bending moment acts on the channel steel 10 due to an external force perpendicularly from the top to the bottom on the outer layer 14C of the upper flange 14. At this time, a compressive stress acts on the upper flange 14 of the channel steel 10 in the direction perpendicular to the cross-section (the direction of the material axis of the channel steel 10), and a tensile stress acts on the lower flange 14 in the direction perpendicular to the cross-section. Therefore, if an excessive bending moment is applied, the upper flange 14 (especially the outer layer 14C) that receives the compressive stress may buckle out of plane, potentially reducing the bending resistance. Furthermore, the channel steel 10 deforms by bending downwards due to the bending moment. At this time, as shown in Figure 14(B), the cross-section of the channel steel 10 deforms such that the upper outer layer 14C that receives the compressive stress and the base 14A located below it are pushed toward the lower opening 16. In Figure 14(B), for the sake of explanation, the deformation behavior of the flange 14 of the channel steel 10 after being subjected to force is illustrated with a dotted line.

[0094] In other words, in this embodiment, when an external bending moment is received by the channel steel 10, the base portion 14A and the outer layer portion 14C are in close contact over almost the entire flange width direction (left-right direction in Figure 14(B)). Due to this close contact, in the section where the bending moment occurs, i.e., the entire region in the flange 14 where compressive stress and tensile stress are distributed along the material axis direction, the base portion 14A and the outer layer portion 14C resist the bending moment while mutually constraining each other in the out-of-plane direction, thereby suppressing buckling due to the compressive stress.

[0095] Furthermore, within the flange 14, the outer layer 14C is partially compressed as a result of the direct action of the out-of-plane external force itself. In this compressed portion, the action of the external force is added, further locally enhancing the mutual restraint between the base 14A and the outer layer 14C caused by the bending moment. As a result, the effect of suppressing buckling due to mutual restraint can be enhanced, eliminating the need to pre-integrate the base 14A and the outer layer 14C by welding or other means.

[0096] On the other hand, as shown in Figure 15(A), consider the case where, even in the channel steel 10Z according to the first comparative example, a bending moment acts on the channel steel 10Z due to an external force acting perpendicularly from top to bottom on the base 14A of the upper flange 14. In this case, similar to the embodiment, a compressive stress acts on the upper flange 14 of the channel steel 10Z in the direction perpendicular to the cross-section, and a tensile stress acts on the lower flange 14 in the direction perpendicular to the cross-section.

[0097] At this time, as shown in Figure 15(B), the cross section of the channel steel 10Z deforms such that the inner layer 14Z and base 14A on the side receiving compressive stress move away from each other and are pushed toward the lower opening 16. As a result, a gap is formed between the base 14A and the inner layer 14Z. In Figure 15(B), as in Figure 14(B), the deformation behavior of the flange 14 of the channel steel 10Z after being subjected to force is illustrated by a dotted line.

[0098] In other words, in the first comparative example, there is no mutual constraint between the base portion 14A and the inner layer portion 14Z. Therefore, when an external bending moment is received by the channel steel 10Z, the base portion 14A, which is separated from the inner layer portion 14Z, resists the compressive stress almost independently. As a result, in the first comparative example, it is difficult to suppress buckling of the upper flange 14 (especially the inner layer portion 14Z) in the out-of-plane direction, and it is difficult to achieve the level of bending resistance obtained in the embodiment.

[0099] Furthermore, Figure 16 illustrates a joint structure in which a channel steel 10Z, representing the first comparative example as the first channel steel, and a channel steel 20, representing the second channel steel, are joined. In the joint structure illustrated in Figure 16, the inner layer 14Z of the channel steel 10Z of the first comparative example and the flange 24 of the channel steel 20 are joined. The joint position in Figure 16 can be identified by the joint 30. A counterbore 14A1 is provided at the position corresponding to the joint 30 in the base 14A of the channel steel 10Z of the first comparative example. The joint 30 is positioned inside the counterbore 14A1 and penetrates both the inner layer 14Z and the flange 24 of the channel steel 20, representing the second channel steel.

[0100] In the channel steel 10Z of the first comparative example, the inner layer 14Z is not directly continuous with the web, but is connected to the web via the base 14A. Also, in the channel steel 10Z of the first comparative example, the connector 30 does not directly contact the base 14A. As a result, the distance along the plate element from the joint position between the channel steel 10Z and the channel steel 20 to the web of the channel steel 10Z becomes longer.

[0101] On the other hand, as illustrated in Figures 10 and 11, in this embodiment, the cross member 320 as the second channel steel is joined to the base portion 14A which is directly continuous with the web 12, rather than to the outer layer portion 14C of the channel steel 10 as the first channel steel. That is, in the first comparative example, where the inner layer portion 14Z is not directly continuous with the web but is connected to the web via the base portion 14A, the total length of the force transmission path formed by the plate portion is longer than in this embodiment when the force acting on the joint flows from the plate portion of the flange to the plate portion of the web.

[0102] In other words, for example, if we assume that a channel steel formed by bending a single steel plate is unfolded back into a single steel plate, then within that single steel plate, the shortest distance between the web portion and the joint position in the first comparative example is longer than the shortest distance in this embodiment. Therefore, in the case of the channel steel 10 joint structure according to the embodiment, in which the channel steel joint structure according to this embodiment is formed, the joint position is closer to the web 12 than in the case of the first comparative example. As a result, the joint strength of the channel steel 10 joint structure according to the embodiment can be increased compared to the joint strength of the joint structure using channel steel 10Z according to the first comparative example. On the other hand, in the first comparative example, the overall length of the force transmission path is longer than in this embodiment, which reduces the efficiency of stress transmission and may induce unnecessary deformation.

[0103] (Equal bending test of channel steel) Next, the equibending test of the channel steel 10 according to the embodiment will be described with reference to Figures 17 to 19. As shown in Figure 17, in the equibending test, a load was applied to both ends of the longitudinal direction L1 in the test section R, which has a constant length in the center of the channel steel 10 according to the embodiment, so that an equibending state is produced in the test section R. In this embodiment, the parts other than the test section R were stiffened to prevent collapse before the test section R, but the presence or absence of stiffening is not limited in this disclosure.

[0104] Then, the magnitude of the bending resistance was measured when an out-of-plane bending force, such as wind pressure, was applied to the channel steel 10. Specifically, the initial elastic stiffness, yield strength, and maximum strength were measured from the time the bending force was applied until the flange 14 buckled and the member strength decreased. Figure 18 illustrates the state in which the outer layer 14C of the flange 14 is deformed in a wavy manner due to buckling.

[0105] Then, the measured initial elastic stiffness, yield strength, and maximum strength values ​​were divided by the target values ​​set for each based on design requirements to calculate the corresponding values. During the constant bending test, the flange 14 did not buckle until the target values ​​for each of these values ​​were reached. That is, after the initial elastic stiffness, yield strength, and maximum strength values ​​exceeded their respective target values, the outer layer 14C buckled as shown in Figure 18.

[0106] The values ​​on the vertical axis in Figure 19 represent the target achievement rate, which is the measured value divided by the target value. As shown in Figure 19, the target achievement rate for initial elastic stiffness was 1.06. The target achievement rate for yield strength was 1.48. The target achievement rate for maximum strength was 1.03.

[0107] The results of the equal bending tests showed that the channel steel 10 according to the embodiment met the target values ​​for initial elastic stiffness, yield strength, and maximum strength. In other words, it was confirmed that the channel steel 10 according to the embodiment met the necessary performance requirements for a frame for panel members in terms of both stiffness and strength as bending resistance.

[0108] (Bending and shear test using a channel steel joint structure) Next, a bending shear test using the channel steel joint structure according to the embodiment of this example will be described with reference to Figures 20 to 22. First, as shown in Figure 20, an L-shaped test specimen having a joint structure of one channel steel 10 as the first channel steel and one channel steel 20 as the second channel steel was prepared as the channel steel joint structure according to the embodiment. In this embodiment, the channel steel 10 and the channel steel 20 were joined by screw joining as a dry joint.

[0109] Next, the channel steel 20 test specimen according to the fabricated embodiment was fixed to a fixing jig 52 having a flat upper surface, which was fixed on the reaction floor 50. Specifically, the plate surface of the web of the channel steel 20 was brought into contact with the upper surface of the fixing jig 52, and the web of the channel steel 20 and the upper part of the fixing jig 52 were bolted together. In addition, the channel steel 10 was positioned so that its longitudinal direction was perpendicular, and a hydraulic jack capable of applying horizontal force was attached to the top of the channel steel 10 as a loading device 54.

[0110] The height HA from the top surface of the fixing jig 42 to the center of the mounting position of the hydraulic jack as the loading device 54 was 500 mm. The longitudinal length D of the channel steel 20 was 250 mm.

[0111] Then, a horizontal force was applied to the channel steel 10 of the test specimen, and while gradually increasing the horizontal force, the deformation-following ability of the channel steel joint structure to in-plane bending shear forces such as seismic forces was confirmed until the joint collapsed. Specifically, the amount of deformation of the channel steel 10 at the applied position was measured during the application of the horizontal force until the load-bearing capacity of the joint in the joint structure deteriorated.

[0112] Furthermore, a test specimen of the joint structure of the channel steel in the second comparative example was prepared. In the second comparative example, two lip channel steels having the same shape and dimensions were joined together. At the joint, the two lip channel steels were joined using wet welding, with the longitudinal end faces of the other lip channel steel butting against the plate faces of the lips of a pair of flanges of one lip channel steel.

[0113] The web height and plate thickness of the lip channel steel in the second comparative example were the same as those of the channel steel 10 in the example. The lip length of the lip channel steel in the second comparative example was 10 mm, and the flange width of the lip channel steel in the second comparative example was set so that its second moment of area around the strong axis was the same as that of the channel steel 10 in the example. The deformation at the horizontal load application position was then measured for the second comparative example as well, in the same manner as in the example.

[0114] Figure 21(A) illustrates the state in which the joint has collapsed in the second comparative example. In the second comparative example, the welded joint has fractured. Figure 21(B) also illustrates the state in which the joint has collapsed in the embodiment. In the embodiment, the screws in the joint have come loose.

[0115] As shown in Figure 22, in the case of the second comparative example, the maximum deformation at the horizontal force application position was 27.1 mm. In the case of the channel steel joint structure according to the embodiment, the maximum deformation at the horizontal force application position was 26.0 mm. In other words, it was found that even in the embodiment with two joint positions by dry joining, the deformation-following ability of the joint structure can be achieved to approximately the same extent as that of the joint structure of the second comparative example using wet welding.

[0116] (Effects and Benefits) In the channel steel 10 according to this embodiment, the outer surface of the base 14A is exposed at the end of the flange 14 in the longitudinal direction L1 because the outer layer 14C is not arranged on the outer surface side of the base 14A. The end of the flange 14 in the longitudinal direction L1 functions as a joint with other structural members. For example, if another channel steel 10 is prepared and the flange 14 of the prepared other channel steel 10 is joined to the outer surface of the base 14A at its end, a joint structure in which two channel steels 10 are joined can be obtained. That is, in the joint structure, the plate thickness of the flange 14 is not increased at the end where the joint is formed, so the burden of the joining work can be reduced compared to the case where the plate thickness at the end where the joint is formed is increased by, for example, folding a part of the flange 14.

[0117] Furthermore, in this embodiment, in the portion of the flange 14 excluding the end in the longitudinal direction L1, i.e., the central portion, the outer layer portion 14C, which is the portion folded back toward the web 12, is arranged on the outer surface side of the base portion 14A, extending in a parallel manner. Therefore, the thickness of the portion of the channel steel 10 excluding the end having the outer layer portion 14C is greater than the thickness of the end portion that does not have the outer layer portion 14C. For example, if the channel steel 10 is formed from a single steel plate 100 with substantially uniform thickness, the thickness of the flange 14 in the portion excluding the end having the outer layer portion 14C can be increased to twice the thickness of the flange 14 at the end portion consisting only of the base portion 14A.

[0118] In other words, in the portion of the channel steel 10 excluding the ends, the steel material is concentrated at the flange 14, which is the outer edge of the cross-section effective in improving bending resistance. Therefore, even if the cross-sectional dimensions are reduced, the bending resistance per unit weight can be strengthened compared to the channel steel 10 without the outer layer 14C. In other words, the bending resistance can be reinforced by the outer layer 14C in the portion excluding the ends, so that the bending resistance does not decrease due to the reduction in cross-sectional dimensions.

[0119] Therefore, according to this embodiment, it is possible to provide a channel steel 10 that can achieve both miniaturization of cross-sectional dimensions and securing bending resistance while suppressing the burden of joining work.

[0120] Furthermore, in this embodiment, the width WC of the outer layer 14C is 50% or more and 100% or less of the flange width WF. Therefore, it is possible to more efficiently achieve both bending resistance, i.e., ensuring rigidity and strength, and miniaturization of the cross-sectional dimensions.

[0121] In the channel steel joining structure according to this embodiment, a first channel steel, configured similarly to the channel steel 10 exemplified in Figure 1, is joined to a second channel steel. This provides a joining structure that can reduce the burden of joining work while simultaneously achieving both miniaturization of the cross-sectional dimensions and securing bending resistance.

[0122] Furthermore, in this embodiment, the thickness of the base portion 14A of the flange 14 of the first channel steel and the thickness of the flange 14 of the second channel steel are the same. Therefore, it is easy to align the outer surface of the flange 14 of the first channel steel (excluding the end portion) with the outer surface of the flange 14 of the second channel steel. In other words, unevenness of the outer surface of the joint can be eliminated. As a result, other members, such as face materials, can be joined to the joint neatly and tightly, thereby increasing the strength of the structural members including the joint structure.

[0123] Furthermore, in this embodiment, when aligning the outer surface of the flange 14 of the portion of the first channel steel excluding the end with the outer surface of the flange 14 of the second channel steel, processing is only required on the first channel steel, eliminating the need to process the shape of the second channel steel in the same way as the first channel steel. In this respect, in the case of the joint structure using the first channel steel of the first comparative example, since the end of the second channel steel is inserted inside the C-shaped groove of the first channel steel, in order to align the outer surfaces flush, it is necessary to process the end of the second channel steel so that it is narrower than the portion excluding the end.

[0124] Furthermore, in this embodiment, unlike the first comparative example, there is no need to process the shape of the second channel steel, so the frame member 300 including the channel steel joint structure can be easily manufactured.

[0125] Furthermore, in this embodiment, one type of steel plate 100 having the same thickness can be used not only as the steel plate 100 for the first channel steel, but also as the steel plate 100 for the second channel steel, thus reducing material costs.

[0126] Furthermore, in this embodiment, the vertical member 310, which serves as the first channel steel, and the horizontal member 320, which serves as the second channel steel, are integrated by dry joining, for example, using screws. In other words, the burden associated with welding, which is a wet joining method that requires skilled techniques, is not necessary. Therefore, the manufacturing burden can be reduced while ensuring the necessary structural performance.

[0127] Furthermore, in this embodiment, there are two joining positions for the base 314A of one flange 314. When there is only one joining position, for example, when joined using one screw at the joining position, the vertical member 310 as the first channel steel and the horizontal member 320 as the second channel steel are prone to rotation around the screw of the fastener 30. In this embodiment, since there are two joining positions for the base 314A of one flange 314, the occurrence of rotation that would occur in the case of one joining position is suppressed. Therefore, the bending moment at the joint is easily transmitted between the first channel steel and the second channel steel. As a result, stable structural performance can be obtained.

[0128] Furthermore, in this embodiment, both the single steel plate 100 constituting the first channel steel and the other single steel plate 100 constituting the second channel steel are pre-plated steel plates. By joining channel steels 10 formed from pre-plated steel plates, it is possible to eliminate the need to perform surface treatment such as plating or painting on the joint structure after joining unplated channel steels, such as by electrodeposition.

[0129] Furthermore, if the joining method in the channel steel joint structure is wet welding, the plated portion will be damaged by welding, requiring repair of the damaged portion after welding. Therefore, in this embodiment, where dry joining without welding is used, there is less burden of repairing the damaged portion compared to when wet welding is used.

[0130] The frame member 300 according to this embodiment includes a joint structure in which a first channel steel is joined to a second channel steel, which allows for both miniaturization of the cross-sectional dimensions and securing bending resistance while suppressing the burden of joining work, as in this embodiment. Therefore, it is possible to achieve both miniaturization of the cross-sectional dimensions of the frame member 300 itself and securing bending resistance.

[0131] The panel member 400 according to this embodiment includes a frame member 300 in which a first channel steel is joined to a second channel steel, which allows for both miniaturization of the cross-sectional dimensions and securing bending resistance while suppressing the burden of joining work, as in this embodiment. Therefore, it is possible to achieve both miniaturization of the cross-sectional dimensions of the panel member 400 itself and securing bending resistance. In addition, because the frame member 300 is made smaller or lighter, it is easier to add members other than the frame member 300 to the panel member 400. Thus, the functions of the surface material 40 can be diversified. Furthermore, it is possible to improve the transportation efficiency of the panel member 400, i.e., improve logistics, and improve the on-site constructability of the panel member 400.

[0132] In the method for manufacturing channel steel according to this embodiment, as in this embodiment, it is possible to manufacture channel steel 10 that can achieve both miniaturization of cross-sectional dimensions and securing bending resistance while suppressing the burden of joining work.

[0133] Furthermore, as explained in the embodiment using Figure 14, in this disclosure, when a bending moment generated by an out-of-plane external force is received by the channel steel 10, the base portion 14A and the outer layer portion 14C are in close contact throughout. Due to this close contact, in the section where the bending moment occurs, the base portion 14A and the outer layer portion 14C resist the bending moment while mutually constraining each other in the out-of-plane direction, thereby suppressing buckling due to the compressive stress. In addition, within the flange 14, the outer layer portion 14C is partially pushed in as a result of the direct action of the out-of-plane external force itself. Since the action of the external force is added in this pushed-in portion, the mutual restraint state between the base portion 14A and the outer layer portion 14C generated by the action of the bending moment is further locally enhanced. As a result, the effect of suppressing buckling by mutual restraint can be increased, so there is no need to pre-integrate the base portion 14A and the outer layer portion 14C by welding or the like.

[0134] Furthermore, the manufacturing method for the channel steel joint structure according to this embodiment makes it possible to realize a channel steel joint structure that can achieve both miniaturization of cross-sectional dimensions and securing bending resistance while suppressing the burden of the joining work.

[0135] <Other Embodiments> While the embodiments described above have illustrated the scope of this disclosure, this description is not intended to limit it. Those skilled in the art should be able to see from this disclosure a variety of alternative embodiments, examples, and operational techniques.

[0136] For example, in this embodiment, as shown in Figure 1, an example is given in which the outer layer portion 14C is arranged on the outer surface side of the base portion 14A in the portion of the flange 14 excluding the end in the longitudinal direction L1. However, this disclosure is not limited to this. In this disclosure, the outer layer portion can be arranged in any number of locations, one or more, at any position other than the end in the longitudinal direction of the flange, for example, at any position in the central portion. By arranging the outer layer portion at any position, the position where the joint structure is formed can be arbitrarily set. In other words, channel steel with a variety of specifications can be realized. Furthermore, by applying the joint structure of channel steel of this disclosure to frame members or panel members, the types of frame members or panel members can also be diversified.

[0137] Furthermore, the configurations shown in Figures 1 to 22 can be partially combined to constitute this disclosure. This disclosure includes various embodiments not described above, and the technical scope of this disclosure is determined solely by the inventive features of the claims that are reasonable from the above description. [Explanation of symbols]

[0138] 10 Channel steel (1st channel steel) 10Z channel steel 12 Web 14 Flange 14A base 14A1 Zabori Hole 14B Folded section 14C Outer layer 14Z Inner Layer 16 Opening 20 Channel steel (second channel steel) 30 Joints 40 facing material 42 Fixing fixture 50 Reaction floor 52 Fixing fixtures 54 Loading device 100 steel plate 120 Web Planning Areas 140 Flange planned area 140A Base area 140B Planned area for the folded section 140C Outer layer planned area 300 Frame members 310 Vertical member (first channel steel) 312 Web 314 Flange 314A base 314C outer layer 320 Cross member (second channel steel) 322 Web 324 Flange 400 Panel Components Corner section A C center line G Gap HA Mounting position height HW Web Direction Height L1 Longitudinal direction L2 Longitudinal direction R Test Section TH1 through hole TH2 through hole V1 virtual line V2 virtual line WF Flange width WC outer layer width X Area to be removed

Claims

1. A joint structure in which a long channel steel, formed from a single steel plate and having a web and a pair of flanges, and a long channel steel, formed from a different steel plate and having a web and a pair of flanges, are joined together with their respective longitudinal directions perpendicular to each other. The pair of flanges of the first channel steel are A strip-shaped base continuous with the web, The folded portion located at the end opposite to the web of the base, The flange comprises a strip-shaped outer layer portion that is positioned on the outer surface side of the base portion in the portion excluding the longitudinal end of the flange, and extends parallel to the base portion from the folded portion toward the web, The pair of flanges of the second channel steel are joined to the outer surfaces of the respective bases at the longitudinal ends of the pair of flanges of the first channel steel. A joint structure for channel steel.

2. The thickness of the base of the flange of the first channel steel and the thickness of the flange of the second channel steel are the same. The joint structure for channel steel according to claim 1.

3. The joining method between the base of the flange of the first channel steel and the flange of the second channel steel is a dry joining. The joint structure for channel steel according to claim 1 or 2.

4. The number of joint positions where the dry joining is performed is two or more for the base of one flange. The joint structure for channel steel according to claim 3.

5. At least one of the aforementioned steel sheet and the other steel sheet is a plated steel sheet. A joint structure for channel steel according to any one of claims 1 to 4.

6. A longitudinal member comprising a long first channel steel formed from a single steel plate and having a web and a pair of flanges, a pair of longitudinal members arranged parallel to each other with space between them, A transverse member comprising a long channel steel, formed from a steel plate separate from the aforementioned steel plate, having a web and a pair of flanges, and having a pair of transverse members joined at each end of the pair of vertical members such that their longitudinal directions are perpendicular to the longitudinal direction of the vertical members, A joint structure for channel steel according to any one of claims 1 to 5 is formed at least one of the joints between the vertical member and the horizontal member. Frame components.

7. The frame member according to claim 6, A surface material provided on the frame member, A panel member equipped with the following features.

8. A method for manufacturing a channel steel joint structure, wherein a long channel steel first, formed from a single steel plate and having a web and a pair of flanges, and a long channel steel second, formed from a different steel plate and having a web and a pair of flanges, are joined together with their respective longitudinal directions perpendicular to each other. A method for manufacturing a long channel steel having a web and a pair of flanges, In a single steel plate having a web area for forming the web and flange areas for forming the pair of flanges, when at least one of the flange areas is divided into a strip-shaped base area continuous with the web area and a strip-shaped outer layer area located on the opposite side of the base area from the web area, A step of removing the longitudinal end of the planned outer layer region in the steel plate, The process involves folding the outer layer area towards the web area, thereby positioning the folded outer layer area as an outer layer above the base area, and forming the base area with the outer layer positioned above it as the base. The steps include: bending the base portion toward the opposite side of the outer layer portion to make it perpendicular to the planned web region, thereby forming the planned web region as the web of the channel steel, and forming the base portion and the outer layer portion as the flange of the channel steel; The pair of flanges of the second channel steel are joined to the outer surfaces of the bases of the pair of flanges of the first channel steel, which is manufactured using a method for manufacturing channel steel that includes the following: A method for manufacturing a joint structure for channel steel.

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