Jointed structures and H-section members

Abstract

To provide a junction structure effectively alleviating strain concentration on a scallop bottom through a simple process.SOLUTION: A junction structure is to joint a H-section beam having flanges and webs on a member to be jointed, wherein a scallop of which the web contacting the flange is partially cut off is formed at an axial end part of the H-section beam welded on the member to be jointed, and an aperture is formed in the web adjacent to the scallop.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a joint structure and an H-shaped cross-section member. [Background technology]

[0002] For example, at the end of an H-section beam that is joined to a column, a scallop is formed by cutting out a portion of the web that contacts the flange. By forming the scallop, it is possible to prevent interference between the weld formed on the flange at the end of the H-section beam and the web. However, there have been cases where cracks have occurred due to strain concentration in the scallop, which is a cross-sectional defect, and the flange has fractured as the cracks have progressed.

[0003] To address this problem, for example, Patent Document 1 describes a technique for reinforcing the portion of an H-section beam where a scallop is formed by joining a tapered plate to the outside of the flange. Patent Document 2 describes a technique for reinforcing the scallop by filling it with welding after welding the flange. Furthermore, Non-Patent Documents 1 to 3 describe scallop shapes that are less likely to concentrate strain, such as shapes that combine arcs with different radii of curvature and shapes that combine arcs and straight lines. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-7194 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-224427 [Non-patent literature]

[0005] [Non-Patent Document 1] Architectural Institute of Japan: Steel Construction Technical Guidelines - Factory Fabrication, Japan, February 15, 2007, 5th edition, pp.208-211 [Non-patent document 2] Tadao Nakagomi and Tetsuya Fujita: Mechanical Performance of Rolled H-Shaped Steel Beam Ends Welded to Square Steel Columns with Through Diaphragms - Effects of Beam Scallops, Shapes, and Misalignments on Fracture Properties, Journal of Structural Engineering, Architectural Institute of Japan, Vol. 455, January 1994, pp. 187-196 [Non-patent document 3] JMRicles, JWFisher, Le-Wu Lu, EJKaufmann;Development of improved welded moment connections for earthquake-resistant design, Journal of Constructional Steel Research, 2002, No. 58, p.565-604 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even with the scallop shapes described in Non-Patent Documents 1 to 3, the concentration of strain near the opening edge of the scallop close to the flange of the H-section beam, that is, at the scallop bottom, is not sufficiently resolved. Since cracks that occur at the scallop bottom close to the flange are likely to lead to fracture of the flange, a reinforcement process such as those described in Patent Documents 1 and 2 is required to prevent this.

[0007] Therefore, an object of the present invention is to provide a joint structure and an H-shaped cross-section member that can effectively relieve the concentration of strain at the scallop bottom using a simple process. [Means for solving the problem]

[0008] [1] A joining structure for joining an H-shaped cross-section beam having a flange and a web to a member to be joined, in which a scallop is formed at the end of the H-shaped cross-section beam in the material axis direction that is welded to the member to be joined, by cutting out a part of the web that contacts the flange, and an opening is formed in the web adjacent to the scallop. [2] The H-shaped cross-section beam has a fillet weld that welds the flange and the web together, or a fillet formed by rolling the flange and the web, and the opening is formed across the web and the fillet weld or the fillet. [1] The joint structure described in [1]. [3] A joining structure according to [2], wherein the centroid of the shape of the opening is located on the web side when viewed in a direction perpendicular to the web. [4] A joining structure described in any one of [1] to [3], wherein the aperture is circular, the edge of the scallop includes one or more arc portions, and the radius of the aperture is equal to or greater than the smallest radius of curvature of the one or more arc portions. [5] A joint structure described in any one of [1] to [4], wherein the shortest distance in the material axis direction between the scallop and the opening is 1.25 times or less the thickness of the web. [6] The joining structure according to [1], further comprising a notch formed to connect the scallop and the opening. [7] An H-shaped cross-section member having a flange and a web, wherein a scallop is formed at at least one end of the H-shaped cross-section member in the material axis direction by cutting out a portion of the web that contacts the flange, and an opening is formed in the web adjacent to the scallop. [Effects of the Invention]

[0009] According to the above configuration, by forming holes in addition to scallops in the web of the H-section beam, it is possible to effectively alleviate the concentration of strain on the scallops with a relatively simple process, without the need to reinforce the area around the scallops or to fill in the scallops themselves. Furthermore, it is possible to alleviate the concentration of strain by forming holes regardless of the shape of the scallops, which is advantageous in that it does not require, for example, a method for processing scallops with a special shape. [Brief explanation of the drawings]

[0010] [Figure 1] 1A and 1B are diagrams illustrating an example of a joining structure according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] 1 is a diagram showing an example of an H-shaped cross-section member according to one embodiment of the present invention. FIG. [Figure 5] 10A and 10B are diagrams showing modified examples of a joining structure according to an embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing dimensions of each member set in the example. [Figure 7] 1 is a graph showing the stress-strain relationship of each member set in an example. [Figure 8] 1 is a graph showing the relationship between equivalent plastic strain and distance x in an example. [Figure 9] 1 is a graph showing the relationship between equivalent plastic strain and distance y in an example. [Figure 10] 1A and 1B are contour diagrams of (a) equivalent plastic strain and (b) shear strain of Comparative Example 1. [Figure 11] FIG. 1 is a contour diagram of (a) equivalent plastic strain and (b) shear strain of Example 1. [Figure 12] FIG. 10 is a contour diagram of (a) equivalent plastic strain and (b) shear strain of Example 2. [Figure 13] FIG. 10 is a contour diagram of (a) equivalent plastic strain and (b) shear strain of Example 3. [Figure 14] FIG. 10 is a contour diagram of (a) equivalent plastic strain and (b) shear strain of Example 4. [Figure 15] FIG. 10 is a contour diagram of (a) equivalent plastic strain and (b) shear strain of Example 5. [Figure 16] FIG. 10 is a contour diagram of (a) equivalent plastic strain and (b) shear strain of Comparative Example 2. 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 explanations will be omitted.

[0012] FIG. 1 illustrates an example of a joint structure according to an embodiment of the present invention. In the illustrated example, the joint structure is formed between an H-shaped beam 1 and a workpiece 2. The workpiece 2 is illustrated as a plate-like member, such as a diaphragm attached to a column, but it may also be the side surface of the column. The H-shaped beam 1 has a flange 11 and a web 12, and the flange 11 is welded to the workpiece 2. Specifically, a weld 4 is formed by filling or stacking weld metal using a backing metal 3 in a groove formed between the end face of the flange 11 in the material axis direction and the workpiece 2. Note that although the flange 11 is illustrated as a lower flange, a similar configuration is also possible for an upper flange. Meanwhile, the web 12 of the H-shaped beam 1 is joined to the workpiece separately from the flange 11. The workpieces to which the flange 11 and the web 12 are joined do not necessarily have to be integral members. For example, the flange 11 may be welded to a diaphragm, and the web 12 may be joined to the side surface of the column to which the diaphragm is attached. In this case, the column and the diaphragm attached to the column constitute the members to be joined to the H-section beam 1.

[0013] At the end of the H-beam 1 in the material axis direction to be joined to the workpiece 2, a scallop 121 is formed by cutting out a portion of the web 12 that contacts the flange 11. The scallop 121 is formed, for example, by cutting before joining the flange 11 and the web 12 to the workpiece 2. Alternatively, if the H-beam 1 is a fabricated H-beam as in the example described below, the scallop 121 may be formed before welding the web 12 to the flange 11. Forming the scallop 121 prevents the weld 4 between the flange 11 and the workpiece 2 from interfering with the web 12. In the illustrated example, the edge of the scallop 121 includes two arc portions, and the radius of curvature r2 of the arc portion closer to the flange 11 is smaller than the radius of curvature r1 of the arc portion farther from the flange 11 (r1>r2).

[0014] Furthermore, in this embodiment, an opening 122 is formed in the web 12 adjacent to the scallop 121. By forming the opening 122 adjacent to the scallop 121, the area that becomes plastic when a large force acts on the joint structure due to an earthquake or the like is expanded not only near the scallop 121 but also near the opening 122, thereby alleviating the concentration of strain at the edge of the scallop 121, particularly at the scallop bottom where the scallop 121 intersects or is close to the flange 11. To effectively alleviate strain, the opening 122 is preferably formed within a predetermined distance from the scallop 121. Specifically, for example, the shortest distance x between the scallop 121 and the opening 122 in the material axis direction of the H-shaped cross-section beam 1 is preferably 1.25 times or less the plate thickness of the web 12. Note that the lower limit of the shortest distance x is not particularly limited and may be 0 or less. In this case, the opening 122 and the scallop 121 are formed continuously. Furthermore, as in an example described later, a notch that connects the scallop 121 and the opening 122 may be formed.

[0015] In the illustrated example, the aperture 122 is circular. While an elliptical or oblong aperture may be formed, a circular aperture 122 is advantageous in that it is easy to machine, for example, using a drill. The radius R of the circular aperture 122 is preferably equal to or greater than the smallest of the radii of curvature r1 and r2 of the arc portions included in the edge of the scallop 121. As described above, the aperture 122 is provided to relieve strain concentration on the scallop 121, and therefore strain also occurs at the edge of the aperture 122. In this case, a larger radius R prevents strain at the edge of the aperture 122 from becoming larger than that at the scallop 121. Therefore, even if a crack occurs at the edge of the aperture 122, the repeated deformation performance can be improved compared to a joining structure in which a beam without apertures 122 fractures from a crack that occurs at the scallop 121.

[0016] 2 and 3 are cross-sectional views taken along lines II-II and III-III in FIG. 1, respectively. The H-beam 1 shown in FIG. 1 may be either a fabricated H-beam or a rolled H-beam. FIG. 2 shows the fabricated H-beam, and FIG. 3 shows the rolled H-beam (lines II-II and III-III in FIG. 1 are the same). In the example shown in FIG. 2, the flange 11 and web 12 of the H-beam 1 are welded by fillet welds 131. This fillet weld 131 forms a connection 13 between the flange 11 and the web 12. Note that, as in the illustrated example, there may be a non-welded portion between the web 12 and the flange 11 between the fillet welds 131 on both sides of the web 12, or the fillet welds 131 on both sides may be integrated, eliminating the non-welded portion. A groove may be formed at the end of the web 12 when the fillet welds are welded. In the following description, the connecting portion 13 refers to a portion formed between the flange 11 and the web 12, which is not within the thickness ranges of the flange 11 and the web 12 (shown by imaginary lines in FIGS. 2 and 3). In the example of FIG. 2, the edge of the connecting portion 13 on the web 12 side is the toe of the fillet weld 131.

[0017] 2, the aperture 122 is formed across the web 12 and the fillet weld 131. When a large force acts on the joint structure due to an earthquake or the like, shear strain becomes dominant at the toe of the fillet weld 131 and the bottom of the scallop near the scallop 121. However, by forming the aperture 122 as described above and having the edge of the aperture 122 intersect with the toe of the fillet weld 131, the shear strain generated at the toe of the fillet weld 131 can be made more dominant, and the concentration of strain on the scallop 121 can be more effectively alleviated.

[0018] On the other hand, in the example shown in FIG. 3 , the flange 11 and web 12 of the H-section beam 1 are integrally formed by rolling, and a fillet 132 is formed between the flange 11 and web 12 during rolling. This fillet 132 forms the connection 13 between the flange 11 and web 12. In the example shown in FIG. 3 , the opening 122 is formed across the web 12 and the fillet 132. When a large force acts on the joint structure due to an earthquake or other event, shear strain predominates near the scallop 121 at the edge of the fillet 132 on the web 12 side, which is a shape change point, and at the scallop bottom. However, by forming the opening 122 as described above and intersecting the edge of the opening 122 with the edge of the fillet 132, the shear strain generated at the edge of the fillet 132 on the web 12 side can be made more prevalent, and the concentration of strain on the scallop 121 can be more effectively alleviated.

[0019] 1 again, in the illustrated example, the center P of the circular opening 122 formed between the web 12 and the connecting portion 13 is located on the web 12 side, not on the connecting portion 13 side. With this arrangement of the openings 122, if a crack initiates from the edge of the opening 122 due to strain distributed from the scallop 121 to the opening 122, the crack can be guided in the axial direction of the H-shaped beam 1 along the edge of the connecting portion 13, i.e., the toe of the fillet weld 131 or the edge of the fillet 132. By suppressing the occurrence of cracks due to strain concentration and guiding the crack, if it does initiate, in the axial direction of the H-shaped beam 1, it is possible to effectively prevent fracture of the flange 11 due to the crack initiated at the scallop 121 or the opening 122 propagating toward the flange 11. Furthermore, even if the opening 122 is not circular, the same effect can be obtained by positioning the centroid of the shape of the opening 122 when viewed in a direction perpendicular to the web 12 on the web 12 side, as in the case of a circular opening.

[0020] FIG. 4 is a diagram illustrating an example of an H-shaped section member according to one embodiment of the present invention. FIG. 4 illustrates the H-shaped beam 1 used in the joining structure illustrated in FIG. 1 before being joined to the workpieces. A groove 111 is formed at the end of the flange 11 of the H-shaped beam 1 in the axial direction. As in this example, the hole 122 may be formed before the H-shaped beam 1 is joined to the workpieces. Specifically, the hole 122 may be formed during manufacturing of the H-shaped beam 1 in a factory, or the hole 122 may be formed after the H-shaped beam 1 is delivered to the construction site as a pre-operation for joining to the workpieces. Alternatively, as an example different from that illustrated in FIG. 4 , the hole 122 may be formed after joining an H-shaped beam 1 without the hole 122 to the workpieces 2. In either case, the hole 122 may be formed by drilling or, for example, gas cutting.

[0021] 5 is a diagram showing a modified example of a joint structure according to an embodiment of the present invention. In the illustrated example, notches 123 are further formed in the H-section beam 1 to connect the scallops 121 and the openings 122. As described above, the openings 122 are formed to relieve strain concentration on the scallops 121, so the scallops 121 and the openings 122 do not need to be spaced apart. Therefore, as already mentioned, the openings 122 may be formed continuous with the scallops 121, or the scallops 121 and the openings 122 may be connected by the notches 123 as in the example of FIG. 5.

[0022] According to the embodiment of the present invention as described above, by forming the openings 122 in addition to the scallops 121 in the web 12 of the H-section beam 1, it is possible to alleviate the concentration of strain on the scallops 121 through a relatively simple process, without the need to reinforce the areas around the scallops 121 or to fill in the scallops themselves. Furthermore, the embodiment of the present invention is advantageous in that it is possible to alleviate the concentration of strain by forming the openings 122 regardless of the shape of the scallops 121, and does not require, for example, a method for processing scallops with special shapes. [Example]

[0023] The analysis results according to the embodiment of the present invention will be explained below. In the analysis, the dimensions of each member were set as shown in Fig. 6, and the stress-strain relationship of each member was set as shown in Fig. 7. The stress-strain relationship shown in Fig. 7 was obtained by converting the tensile test results of the material in a previous experiment into a true stress-true strain relationship and approximating it with multiple lines. The flange and web of the H-section beam were assumed to be joined by submerged arc welding (SAW), and the leg length of the SAW was set to 12 mm. The flange and the member to be joined were assumed to be joined by CO2 welding. The yield stress (σ y ,σ wy ) are all 367N / mm 2 The member angle θ at the time of full plastic strength at the beam end p is 0.00765rad, and the total plastic moment M p was set at 1705.3kNm.

[0024] The radius of the aperture was 15 mm. As shown in Table 1, the strain relaxation effect was verified for Comparative Example 1, in which no aperture was formed; Examples 1 to 5, in which the shortest distance x between the scallop and the aperture in the material axis direction of the H-shaped cross-section beam was varied; and Comparative Example 2, in which the distance y from the top surface of the flange (the surface joined to the web) to the center of the aperture was increased to form the aperture at a position farther from the scallop. Eight-node elements were used, and the loading method was monotonic loading, in which a forced displacement D was applied in one direction to the tip of the beam. The von Mises yield criterion was used, and the analysis was performed using the general-purpose nonlinear structural analysis program "Marc2021."

[0025] [Table 1]

[0026] FIG. 8 shows the results of the experiment with Examples 1 to 5 and Comparative Example 1, where the member angle is 3θ p The equivalent plastic strain ε of the element in the scallop where strain is highest when eq 9 is a graph showing the relationship between the distance x and the equivalent plastic strain ε . The equivalent plastic strain in Comparative Example 1 is shown as a reference value, and the value corresponding to 80% of that is also shown. Similarly, FIG. 9 shows the relationship between the equivalent plastic strain ε eq 10 to 16 are contour diagrams of (a) equivalent plastic strain and (b) shear strain for each example and comparative example.

[0027] As shown in the contour diagram of Figure 10, in Comparative Example 1, where no apertures are formed, plastic shear strain increases at two locations: the scallop bottom and the weld toe, and as a result, equivalent plastic strain also increases at both locations. In contrast, as shown in the contour diagrams of Figures 11 to 15, in Examples 1 to 5, where apertures are formed, the plastic shear strain at the aperture and SAW toe becomes dominant during loading, causing the SAW toe to yield first, and as a result, the plastic shear strain and equivalent plastic strain at the scallop bottom are alleviated.

[0028] As shown in the graph in Fig. 8, the equivalent plastic strain ε at the bottom of the scallop eq shows a tendency to become smaller as the distance x becomes shorter. More specifically, in Examples 1 to 3 where the distance x is 15 mm or less, that is, 1.25 times the web thickness or less, the equivalent plastic strain ε eq is alleviated by 20% or more compared to Comparative Example 1. The equivalent plastic strain ε eq The approximate straight line of the equivalent plastic strain ε eq That is, in the analysis results according to the example, when the distance x is 1.25 times the web thickness or less, the effect of alleviating strain becomes more pronounced.

[0029] 11 and 12, in Examples 1 and 2 where the distance x is shorter than 15 mm and the hole is close to the scallop, the equivalent plastic strain at the scallop bottom is significantly relaxed, and the shear strain increases further in the direction from the hole to the SAW toe. When the shear strain increases in the direction along the SAW toe in this way, if a crack propagates to the hole, the crack will propagate from there in the direction along the SAW toe, and cracks that propagate in the flange plate thickness direction from the scallop bottom or the hole are less likely to occur.

[0030] On the other hand, as shown in the contour diagram of Figure 16, in Comparative Example 2, in which the distance y was increased and the hole was formed at a position away from the scallop in the beam depth direction, the shear strain at the SAW toe could not be increased, so the strain at the scallop bottom was not alleviated, and rather the cross-sectional loss caused by the hole had an effect, resulting in a larger strain than in Comparative Example 1 in which no hole was formed.

[0031] 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 idea described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention. [Explanation of symbols]

[0032] 1...H-shaped cross-section beam, 2...joined members, 3...backing plate, 4...weld portion, 11...flange, 12...web, 13...connecting portion, 111...groove surface, 121...scallop, 122...opening, 123...notch, 131...fillet weld portion, 132...fillet portion.

Claims

1. A joining structure for joining an H-shaped cross-section beam having a flange and a web to a joined member, At the end of the H-section beam in the material axis direction to be welded to the joined member, a scallop is formed by cutting out a part of the web that contacts the flange, Apertures are formed in the web adjacent to the scallops; The H-shaped cross section beam has a fillet welded portion for welding the flange and the web, or a fillet portion formed by rolling the flange and the web, The opening is a joining structure formed across the web and the fillet weld or the fillet portion.

2. The joining structure according to claim 1 , wherein when viewed in a direction perpendicular to the web, the centroid of the shape of the opening is located on the web side.

3. the aperture is circular; the scalloped edge includes one or more arcuate portions; 3. The joining structure according to claim 1, wherein the radius of the hole is equal to or greater than the smallest radius of curvature of the one or more arc portions.

4. The joining structure according to claim 1 , wherein the shortest distance between the scallop and the hole in the material axis direction is 1.25 times or less the plate thickness of the web.

5. The joint structure according to claim 1 , further comprising a notch that connects the scallop and the opening.

6. An H-section member having a flange and a web, At least one end of the H-shaped cross-section member in the material axis direction is formed with a scallop by cutting out a part of the web that contacts the flange, Apertures are formed in the web adjacent to the scallops; The H-shaped cross-section member has a fillet weld portion for welding the flange and the web together, or a fillet portion formed by roll-forming the flange and the web together, The opening is formed across the web and the fillet weld or the fillet portion of the H-shaped cross-section member.

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