Steel beam and method of manufacturing the same

Abstract

To provide an H-shaped steel beam capable of securing high plastic deformation performance against an earthquake load with a simple structure without complicating a shape of a horizontal haunch in the H-shaped steel beam provided with the horizontal haunch at an end in a material axial direction, and a method for manufacturing the H-shaped steel beam.SOLUTION: There is provided an H-shaped steel beam in which a horizontal haunch is provided at an end portion in a material axis direction, the horizontal haunch is welded and joined to a beam flange, weld metal between the horizontal haunch and the beam flange is continuously provided so as to be extended to a center side in the material axis direction by a length Lw from a widening start position by the horizontal haunch, and the length Lw satisfies a predetermined relationship.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an H-shaped steel beam that is connected to a column in an architectural structure that requires earthquake resistance, and a manufacturing method thereof. [Background technology]

[0002] In building structures, as shown in Figures 14 and 15, in order to improve the earthquake resistance of H-shaped steel beams 1 connected to columns 2, horizontal haunches 13 are provided at the ends of the H-shaped steel beams 1 in the axial direction to widen the beam flanges 11, thereby reducing the stress acting on the ends of the H-shaped steel beams 1 during earthquakes. Various studies have been conducted on the shape of these horizontal haunches 13.

[0003] For example, Patent Document 1 discloses a beam-column joint structure in which a through hole is provided in a horizontal haunch welded to a beam flange. According to Patent Document 1, a through hole is formed in the portion of the increased cross-sectional area portion of the horizontal haunch that protrudes outward in the width direction of the beam flange beyond the reference cross-sectional area. This reduces the difference in rigidity between the reference cross-sectional area and the increased cross-sectional area portion, and alleviates stress concentration at the boundary between the reference cross-sectional area and the increased cross-sectional area portion, i.e., the corner at the position where the cross section suddenly changes.

[0004] Furthermore, Patent Document 2 discloses a beam member composed of a haunch start portion, which is the position where widening by the horizontal haunch begins, a straight portion, and a haunch end portion located at the end of the beam in the material axis direction. By providing arc portions at the haunch start portion and the haunch end portion, the stress concentration coefficient at the haunch start portion and the end portion is set to 3 or less. According to Patent Document 2, by suppressing stress concentration at the haunch start portion and the haunch end portion, the beam can fully demonstrate its plastic deformation performance and improve its earthquake resistance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5953871 [Patent Document 2] Patent No. 4655491 Summary of the Invention [Problem to be solved by the invention]

[0006] However, defects such as poor penetration and blowholes are generally likely to occur at the start of a weld, while defects such as crater cracks are likely to occur at the end of a weld.

[0007] In the method described in Patent Document 1, the start or end of the weld is close to the location of the sudden change in cross section caused by the horizontal haunch. Therefore, if there is a defect in the start or end of the weld, the defect may cause premature fracture of the beam flange at the location of the sudden change in cross section. Furthermore, repairing a weld defect near the location of the sudden change in cross section increases the cost of the repair and lengthens the construction period. Furthermore, since a through hole must be drilled in the horizontal haunch, the cost of drilling the through hole increases.

[0008] Furthermore, in the method described in Patent Document 2, the shape of the widened portion due to the horizontal haunch is complex, making it difficult to ensure precision in manufacturing the beam member due to bending that occurs when cutting the widened portion from the steel plate and complex thermal deformation that occurs when welding the widened portion. Furthermore, while general haunch processing is performed using inexpensive gas cutting, gas cutting can sometimes leave tiny notches on the cut surface, which can become the starting point for fractures.

[0009] The present invention has been made to solve such problems, and aims to provide an H-shaped steel beam having a horizontal haunch at the end in the axial direction of the beam, which has a simple structure without complicating the shape of the horizontal haunch and can ensure high plastic deformation performance against earthquake loads, and a method for manufacturing an H-shaped steel beam. [Means for solving the problem]

[0010] The present inventors have conducted extensive research into a method for improving the plastic deformation capacity of an H-shaped steel beam using a horizontal haunch, as well as a simple method for manufacturing an H-shaped steel beam. As a result, they have found that by extending the weld metal toward the center of the H-shaped steel beam in the axial direction when welding the horizontal haunch to the beam flange, the plastic deformation capacity of the H-shaped steel beam can be significantly improved without complicating the shape of the horizontal haunch. The present invention was achieved as a result of further research based on the above findings, and its gist is as follows.

[0011] In order to solve the above problems, the present invention has the following features.

[0012] [1] An H-shaped steel beam provided with a horizontal haunch at the end in the material axis direction, the horizontal haunch is welded to the beam flange, and the weld metal between the horizontal haunch and the beam flange is a length L from the widening start position by the horizontal haunch. w The length L w H-shaped steel beam that satisfies the relationship in equation (1) below.

[0013]

number

[0014] However, L (mm) is the distance from the widening start position to the inflection point of the bending moment acting in the axial direction of the H-shaped steel beam, bf1 M p (N·mm) is the full plastic bending moment of the beam flange and weld metal at the widening start position, and is expressed by the following formula (2): bf2 M p (N·mm) is the length L from the widening start position w The full plastic bending moment of the beam flange at the center position in the material axis direction is expressed by the following formula (3): bw M p (N·mm) is the total plastic bending moment of the beam web, which is expressed by the following equation (4), and D b (mm) is beam depth, B b(mm) is the beam width, t f (mm) is the thickness of the beam flange, t w (mm) is the thickness of the beam web, σ fy (N / mm 2 ) is the yield stress of the beam flange, σ wy (N / mm 2 ) is the yield stress of the beam web, B w (mm) is the width of the weld metal between the horizontal haunch and the beam flange at the center of the beam flange thickness.

[0015]

number

[0016]

number

[0017]

number

[0018] [2] A manufacturing method of an H-shaped steel beam in which a horizontal haunch is provided at the end in the material axis direction, wherein the weld metal between the horizontal haunch and the beam flange is welded by a length L from the widening start position by the horizontal haunch. w The length L w A manufacturing method of an H-shaped steel beam, which satisfies the relationship of the following equation (1).

[0019]

number

[0020] However, L (mm) is the distance from the widening start position to the inflection point of the bending moment acting in the axial direction of the H-shaped steel beam, bf1 M p (N·mm) is the full plastic bending moment of the beam flange and weld metal at the widening start position, and is expressed by the following formula (2): bf2 M p(N·mm) is the length L from the widening start position w The full plastic bending moment of the beam flange at the center position in the material axis direction is expressed by the following formula (3): bw M p (N·mm) is the total plastic bending moment of the beam web, which is expressed by the following equation (4), and D b (mm) is beam depth, B b (mm) is the beam width, t f (mm) is the thickness of the beam flange, t w (mm) is the thickness of the beam web, σ fy (N / mm 2 ) is the yield stress of the beam flange, σ wy (N / mm 2 ) is the yield stress of the beam web, B w (mm) is the width of the weld metal between the horizontal haunch and the beam flange at the center of the beam flange thickness.

[0021]

number

[0022]

number

[0023]

number

[0024] [3] A manufacturing method of an H-shaped steel beam described in [2], in which, when welding between the beam flange and the horizontal haunch, a groove is machined on the horizontal haunch side, and a ceramic tab having the same groove shape as the groove machined on the horizontal haunch side is used to extend the groove of the horizontal haunch toward the center in the material axis direction.

[0025] [4] A method for manufacturing an H-shaped steel beam described in [2] or [3], in which, when welding between the beam flange and the horizontal haunch, an I-shaped groove with an angle of 5° or less or a R-shaped groove with an angle of 35° or less is made on the horizontal haunch side. [Effects of the Invention]

[0026] According to the H-shaped steel beam of the present invention, the horizontal haunch is provided at the end in the material axis direction of the H-shaped steel beam, and the horizontal haunch is welded to the beam flange. The weld metal between the horizontal haunch and the beam flange extends from the start position of the widening by the horizontal haunch to a length L w The length L w satisfies the relationship of the above equation (1).

[0027] As a result, the plastic deformation of the beam flange at the widening start position due to the horizontal haunch is restrained by the weld metal extended from the widening start position toward the center in the material axis direction, expanding the plasticized region of the beam flange and mitigating the stress and strain concentration of the beam flange at the widening start position. Furthermore, the H-shaped steel beam can reach full plastic bending moment first at the widening start position due to the horizontal haunch, and no fracture occurs at the tip of the extended weld metal before the H-shaped steel beam reaches its ultimate state.

[0028] In addition, since the beginning and end of the weld, where defects are likely to occur, are separated from the widening start point, premature fracture of the beam flange caused by a weld defect during an earthquake is less likely to occur, and the plastic deformation performance of the H-shaped steel beam can be significantly improved without complicating the shape of the horizontal haunch.

[0029] Furthermore, according to the manufacturing method of the H-shaped steel beam of the present invention, in addition to the above-mentioned effects, it is possible to improve the manufacturing efficiency of H-shaped steel beams having horizontal haunches at the ends in the material axis direction. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a plan view schematically showing a state in which an H-shaped steel beam according to a first embodiment of the present invention is joined to a square steel pipe column. [Figure 2] FIG. 2 is a plan view showing the arrangement of ceramic backing materials and ceramic tabs used when welding horizontal haunches to beam flanges in the manufacturing method for an H-shaped steel beam according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing an example of a groove shape of a welded portion between a horizontal haunch and a beam flange in a manufacturing method of an H-shaped steel beam according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing another example of the groove shape of the welded portion between the horizontal haunch and the beam flange in the manufacturing method of the H-shaped steel beam according to the first embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view showing yet another example of the groove shape of the welded portion between the horizontal haunch and the beam flange in the manufacturing method of an H-shaped steel beam according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a plan view schematically showing a welding state between a horizontal haunch and a beam flange in the manufacturing method of an H-shaped steel beam according to the first embodiment of the present invention. [Figure 7] FIG. 7 is a plan view schematically showing a welding state between a horizontal haunch and a beam flange in the manufacturing method of an H-shaped steel beam according to the first embodiment of the present invention. [Figure 8] FIG. 8 is a plan view schematically showing a state in which an H-shaped steel beam according to the second embodiment of the present invention is joined to a square steel pipe column. [Figure 9] FIG. 9 is a plan view schematically showing a state in which an H-shaped steel beam according to the third embodiment of the present invention is joined to a square steel pipe column. [Figure 10] FIG. 10 is a plan view schematically showing a state in which an H-shaped steel beam according to the fourth embodiment of the present invention is joined to a square steel pipe column. [Figure 11] FIG. 11 is a side view showing an analytical model used in a numerical analysis carried out to verify the effect of the H-shaped steel beam of the present invention. [Figure 12] FIG. 12 is a plan view showing a main part of an analytical model in a numerical analysis carried out to verify the effect of the H-shaped steel beam of the present invention. [Figure 13] Figure 13(a) is a contour diagram of equivalent plastic strain obtained by a numerical analysis conducted to verify the effects of the H-shaped steel beam of the present invention, and Figure 13(b) is a contour diagram of equivalent plastic strain obtained by conducting a similar numerical analysis on a conventional H-shaped steel beam. [Figure 14]FIG. 14 is a perspective view schematically showing a state in which an H-shaped steel beam having a horizontal haunch is joined to a square steel pipe column. [Figure 15] FIG. 15 is a plan view schematically showing a state in which an H-shaped steel beam equipped with a horizontal haunch is joined to a square steel pipe column. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments of an H-shaped steel beam and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings.

[0032] FIG. 1 is a schematic diagram showing a state in which an H-shaped steel beam according to a first embodiment of the present invention is joined to a square steel pipe column.

[0033] As shown in Fig. 1, the H-shaped steel beam 1 according to the first embodiment of the present invention is an H-shaped steel beam in which a horizontal haunch 13 is provided at the end in the material axis direction to widen the beam flange 11. The horizontal haunch 13 is welded to the beam flange 11, and the weld metal 14 between the horizontal haunch 13 and the beam flange 11 extends from the widening start position P by the horizontal haunch 13 toward the center of the material axis direction of the H-shaped steel beam 1 by a length L w The wires are provided continuously so as to extend only by a certain distance.

[0034] Here, the extension length L of the weld metal 14 between the horizontal haunch 13 and the beam flange 11 from the widening start position P by the horizontal haunch 13 to the center side in the material axis direction w shall satisfy the relationship of the following equation (1).

[0035]

number

[0036] Here, L (mm) is the distance from the widening start position P by the horizontal haunch 13 to the inflection point of the bending moment acting in the axial direction of the H-shaped steel beam 1. bf1 M p(N·mm) is the full plastic bending moment of the beam flange 11 and the weld metal 14 at the widening start position P by the horizontal haunch 13, and is expressed by the following equation (2). bf2 M p (N·mm) is the distance L from the widening start position P by the horizontal haunch 13 w This is the total plastic bending moment of the beam flange 11 at a position on the central side in the material axis direction, and is expressed by the following formula (3). bw M p (N·mm) is the total plastic bending moment of the beam web, which is expressed by the following equation (4): D b (mm) is beam depth, B b (mm) is the beam width, t f (mm) is the thickness of the beam flange, t w (mm) is the thickness of the beam web, σ fy (N / mm 2 ) is the yield stress of the beam flange, σ wy (N / mm 2 ) is the yield stress of the beam web. B w (mm) is the width of the weld metal 14 between the horizontal haunch 13 and the beam flange 11 at the center of the plate thickness of the beam flange.

[0037]

number

[0038]

number

[0039]

number

[0040] The left side of the above equation (1) represents the shear force of the H-shaped steel beam 1 when the H-shaped steel beam 1 and the weld metal 14 reach a fully plastic state at the widening start position P by the horizontal haunch 13. The right side of the above equation (1) represents the shear force of the H-shaped steel beam 1 when the H-shaped steel beam 1 reaches a fully plastic state at the tip of the extended weld metal 14.

[0041] By designing the H-shaped steel beam 1 so that it reaches full plastic bending moment first at the widening start position P by the horizontal haunch 13, no fracture occurs at the tip of the extended weld metal 14 before the H-shaped steel beam 1 reaches its ultimate state. In addition, the plastic deformation of the beam flange 11 at the widening start position P by the horizontal haunch 13 is restrained by the weld metal 14 extended from the widening start position P by the horizontal haunch 13 toward the center in the material axis direction of the H-shaped steel beam 1, expanding the plasticized region of the beam flange 11 and alleviating the stress and strain concentration of the beam flange 11 at the widening start position P.

[0042] In addition, since the beginning and end of the weld, which are prone to defects, are separated from the widening start position P, early fracture of the beam flange 11 caused by a weld defect during an earthquake is less likely to occur, and the plastic deformation performance of the H-shaped steel beam 1 can be significantly improved without complicating the shape of the horizontal haunch 13.

[0043] Extension length L of weld metal 14 w If the relationship of the above formula (1) is not satisfied, the effect of the weld metal 14 in restraining the plastic deformation of the beam flange 11 will not be sufficient, and stress will be concentrated at the interface between the end of the weld metal 14 and the beam flange 11, which may prevent the plastic deformation performance of the H-shaped steel beam 1 from being sufficiently improved. w There is no particular limitation as long as the relationship of the above formula (1) is satisfied. However, in order to suppress an increase in the process and cost due to an increase in the welding length, the extension length L of the weld metal 14 is w It is preferable that the distance is 300 mm or less.

[0044] It is common to apply overmatch welding so that the yield strength of the weld metal 14 between the horizontal haunch 13 and the beam flange 11 is greater than the yield strength of the beam flange 11. In the present invention, too, it is preferable that the horizontal haunch 13 and the beam flange 11 are joined by overmatch welding.

[0045] FIG. 2 shows the arrangement of ceramic backing material 15 and ceramic tabs 16 used when welding the horizontal haunch to the beam flange in the manufacturing method of the H-shaped steel beam according to the first embodiment of the present invention.

[0046] As will be described later, when welding between the beam flange 11 and the horizontal haunch 13, it is preferable to machine a groove on the horizontal haunch 13 side and then perform welding on this groove. At this time, as shown in Fig. 2, it is preferable to extend the groove of the horizontal haunch 13 toward the center in the material axis direction by using a ceramic tab 16 machined or shaped to have the same groove shape as the groove machined on the horizontal haunch 13 side. In this way, the weld metal 14 between the horizontal haunch 13 and the beam flange 11 is extended by a length L from the widening start position P by the horizontal haunch 13 toward the center in the material axis direction of the H-shaped steel beam 1. w The wires may be provided continuously so as to extend only as far as the wires.

[0047] If a steel tab rather than a ceramic tab 16 is used to continuously form the weld metal 14 between the horizontal haunch 13 and the beam flange 11, extending from the widening start position P by the horizontal haunch 13 toward the center of the H-shaped steel beam 1 in the axial direction, the steel tab would remain on the side of the weld metal 14 after welding. In this case, stress would concentrate in the beam flange 11 near the slit between the steel tab and the horizontal haunch 13 during an earthquake, potentially leading to premature fracture of the beam flange 11 originating from the slit. In contrast, if a ceramic tab 16 is used to continuously form the weld metal 14 between the horizontal haunch 13 and the beam flange 11, extending from the widening start position P by the horizontal haunch 13 toward the center of the H-shaped steel beam 1 in the axial direction, the ceramic tab 16 can be removed after welding the horizontal haunch 13 and the beam flange 11. This prevents a slit from forming between the beam flange 11 and the tab at the widening start position P, preventing premature fracture of the beam flange 11 originating from the slit.

[0048] The ceramic backing material 15 shown in FIG. 2 may be replaced by a steel backing material.

[0049] Figures 3(a), 3(b), 4(a), 4(b), and 5 show several examples of groove shapes at the weld between the horizontal haunch and the beam flange in an H-shaped steel beam according to the first embodiment of the present invention. Figures 3(a), 3(b), 4(a), 4(b), and 5 show groove shapes at the position of the AA cross section line in Figure 1. Figures 3(a) and 3(b) show cases where the groove shape is I-shaped, Figures 4(a) and 4(b) show cases where the groove shape is V-shaped, and Figure 5 shows cases where the groove shape is K-shaped.

[0050] When welding between the beam flange 11 and the horizontal haunch 13, a K-groove G3 is often used to reduce the amount of welding, as shown in Figure 5. However, when using the K-groove G3, after welding the top side of the beam flange 11, it becomes necessary to turn the H-shaped steel beam 1 over when welding the bottom side, which increases the labor required for turning it over.

[0051] For this reason, when welding between the beam flange 11 and the horizontal haunch 13, it is preferable to make an I-shaped groove on the horizontal haunch 13 side as shown in Figures 3(a) and 3(b), or to make a V-shaped groove as shown in Figures 4(a) and 4(b). In this way, by welding the horizontal haunch 13 provided with an I-shaped groove G1 or a V-shaped groove G2 from the top side of the beam flange 11, there is no need to flip the H-shaped steel beam 1 during welding, which shortens the member manufacturing process.

[0052] Furthermore, when an I-groove G1 is used as shown in Figures 3(a) and 3(b), the groove angle θ is preferably set to 5° or less, and when a V-groove G2 is used as shown in Figures 4(a) and 4(b), the groove angle θ is preferably set to 35° or less. This prevents the amount of welding between the horizontal haunch 13 and the beam flange 11 from increasing.

[0053] 6 and 7 show schematic diagrams of welding between the horizontal haunch 13 and the beam flange 11 in the manufacturing method of an H-shaped steel beam according to the first embodiment of the present invention. Fig. 6 shows a case where welding is performed in the direction from the tip E of the H-shaped steel beam 1 in the axial direction toward the position P where widening by the horizontal haunch 13 starts, and Fig. 7 shows a case where welding is performed in the direction from the position P where widening by the horizontal haunch 13 starts toward the tip E of the H-shaped steel beam 1 in the axial direction.

[0054] The welding direction of the weld metal 14 between the horizontal haunch 13 and the beam flange 11 may be either of the directions shown in Figures 6 and 7. After the horizontal haunch 13 is welded to the beam flange 11, the H-shaped steel beam 1 is joined to the column 2, so grooves are formed on the beam flange 11 and the horizontal haunch 13 at the tip E of the H-shaped steel beam 1 in the material axis direction.

[0055] 8 to 10 are schematic diagrams showing the state in which H-shaped steel beams according to second to fourth embodiments of the present invention are joined to square steel pipe columns.

[0056] As in the first embodiment shown in FIG. 1 , the planar shape of the horizontal haunch 13 of the H-shaped steel beam 1 according to the present invention is basically a trapezoid, but is not limited thereto. For example, as in the second embodiment shown in FIG. 8 , the planar shape of the horizontal haunch 13 of the H-shaped steel beam 1 may be a pentagon. This makes it easier to connect the ceramic tab 16 shown in FIG. 2 to the horizontal haunch 13. Alternatively, as in the third embodiment shown in FIG. 9 , a portion of the widening portion caused by the horizontal haunch 13 may be removed in the shape of a circular arc 17. This reduces local stress concentration at the widening start position P caused by the horizontal haunch 13. Furthermore, as in the fourth embodiment shown in FIG. 10 , the horizontal haunch 13 may be shaped to extend along the weld metal 14 extending from the widening start position P toward the center of the H-shaped steel beam 1 in the material axis direction. This eliminates the need to connect the ceramic tab 16 to the horizontal haunch 13.

[0057] The above describes the embodiments of the H-shaped steel beam and the manufacturing method thereof of the present invention. The specific configurations of the H-shaped steel beam and the manufacturing method thereof of the present invention are not limited to the above-mentioned embodiments, and can be appropriately modified within the scope of the present invention.

[0058] For example, the H-shaped steel beam and the manufacturing method thereof according to the present invention can be applied to both rolled H-shaped steel and welded H-shaped steel.

[0059] As shown in Figure 1, the H-shaped steel beam and its manufacturing method according to the present invention are based on the fact that the H-shaped steel beam is connected to a column having a square or box-shaped cross section. However, in the present invention, there are no particular restrictions on the shape of the column to which the H-shaped steel beam is connected; it may be connected to a column made of a circular steel pipe or an H-shaped steel. Furthermore, the columns may be made of not only steel but also concrete-filled steel pipes, which have steel frames filled with concrete to enhance earthquake resistance. Furthermore, the columns may be made of steel-reinforced concrete, a composite structure of steel and concrete.

[0060] Furthermore, the H-shaped steel beam and its manufacturing method according to the present invention are based on the application of a through diaphragm type to the joint between the H-shaped steel beam and the column. However, in the present invention, there is no need to impose any particular restrictions on the type of joint between the H-shaped steel beam and the column, and other joint types such as an inner diaphragm type or an outer diaphragm type can be applied. [Example]

[0061] Regarding the H-shaped steel beam of the present invention, a numerical analysis was carried out using the finite element method on a T-shaped frame composed of square steel pipe columns and H-shaped steel beams, and the performance of the H-shaped steel beam of the present invention was verified based on the results of this numerical analysis. The results are explained below.

[0062] Figure 11 shows a side view of the analytical model used in this numerical analysis. Figure 12 shows a plan view of the main parts of the analytical model. As shown in Figure 11, the dimensions of the H-shaped steel beams in the analytical model were H-600 x 200 x 16 x 25 (units: mm) and a length of 2550 mm, and the material properties were set to simulate the steel grade SN490B specified in the Japanese Industrial Standard JIS G3136 (rolled steel for building structures). The dimensions of the square steel pipe columns in the analytical model were □-500 x 500 x 19 x 19 (units: mm) and a length of 2000 mm, and the material properties were set to simulate the steel grade SN490B specified in the Japanese Industrial Standard JIS G3136 (rolled steel for building structures).

[0063] As shown in Fig. 12, the subject of this numerical analysis was an analytical model in which an H-shaped steel beam 1, in which a beam flange 11 is widened by providing a horizontal haunch 13 at the end in the material axis direction, is joined to the side surface of a square steel pipe column 2. The weld metal 14 between the horizontal haunch 13 and the beam flange 11 was set to simulate a state in which welding was performed on an I-groove with a groove angle θ of 0° provided on the horizontal haunch 13 side, as shown in Fig. 3. The yield strength of the weld metal 14 was set to 1.3 times the yield strength of the beam flange 11.

[0064] In this numerical analysis, the extension length L of the weld metal 14 between the horizontal haunch 13 and the beam flange 11 from the widening start position P by the horizontal haunch 13 to the center in the material axis direction is w The analysis parameters were as follows: w The width B of the weld metal 14 was changed to two values: 0 mm (conventional example) and 125 mm (example of the present invention). w In the example of the present invention, the extension length L of the weld metal 14 is 10 mm. w and the width of the weld metal B w In the conventional example, the width-expansion start position P and the end position of the weld metal 14 coincide with each other, and the extension length L of the weld metal 14 w and the width of the weld metal B w However, the relationship of the above formula (1) is not satisfied.

[0065] Then, as shown in Figure 11, under the condition that the upper and lower ends of the square steel pipe column 2 were pin-supported, a downward shear force V was applied to the tip of the H-shaped steel beam 1, and a numerical analysis was performed using displacement control in which the displacement of the tip of the H-shaped steel beam 1 was monotonically increased until each member of the H-shaped steel beam 1 reached 0.05 rad.

[0066] Figures 13(a) and 13(b) show contour diagrams of the equivalent plastic strain generated in the beam flange 11 of the H-shaped steel beam 1, obtained by the above-mentioned numerical analysis, for the example of the present invention and the conventional example. The contour diagrams shown in Figures 13(a) and 13(b) show the equivalent plastic strain generated in the region of the beam flange 11 of the H-shaped steel beam 1 that includes the widening start position P by the horizontal haunch 13, when the member angle of the H-shaped steel beam 1 becomes 0.05 rad.

[0067] As shown in FIG. 13(b), the weld metal 14 between the horizontal haunch 13 and the beam flange 11 is not extended toward the center of the H-shaped steel beam 1 in the material axis direction, and the extension length L w and the width of the weld metal B w However, in the conventional example that does not satisfy the relationship of the above formula (1), the maximum value of the equivalent plastic strain was 3.3%. w and the width of the weld metal B w However, in the example of the present invention, which satisfied the relationship of the above formula (1), the maximum value of the equivalent plastic strain was 2.3%. In this way, it was confirmed that by extending the weld metal 14 between the horizontal haunch 13 and the beam flange 11 from the widening start position P by the horizontal haunch 13 toward the center in the material axis direction of the H-shaped steel beam 1 so as to satisfy the relationship of the above formula (1), the strain concentration at the widening start position P of the beam flange 11 of the H-shaped steel beam 1 is alleviated, and the equivalent plastic strain can be reduced. [Explanation of symbols]

[0068] 1 H-shaped steel beam 2 pillars 3 diaphragm 11 Beam flange 12 Beam web 13 Horizontal haunch 14 Weld metal 15 Backing material 16 Ceramic Tab 17 Arc L w Extended length of weld metal B w Weld metal width P Widening start position E Tip in material axis direction G1 I-bevel G2 Rectangular bevel G3 K-shaped bevel θ Bevel angle

Claims

1. An H-shaped steel beam having a horizontal haunch at the end in the material axis direction, the horizontal haunch is welded to the beam flange; The weld metal between the horizontal haunch and the beam flange has a length L from the widening start position by the horizontal haunch. w The grooves are continuously provided so as to extend only toward the center in the material axis direction, The length L w An H-shaped steel beam that satisfies the relationship in the following equation (1). [Equation 1] however, L (mm) is the distance from the widening start position to the inflection point of the bending moment acting in the axial direction of the H-shaped steel beam, bf1 M p (N mm) is the full plastic bending moment of the beam flange and the weld metal at the widening start position, and is expressed by the following formula (2): bf2 M p (N mm) is the length L from the widening start position w The full plastic bending moment of the beam flange at the center position in the material axis direction is expressed by the following formula (3): bw M p (N mm) is the total plastic bending moment of the beam web, expressed by the following equation (4): D b (mm) is beam depth, B b (mm) is the beam width, t f (mm) is the thickness of the beam flange, t w (mm) is the thickness of the beam web, σ fy (N / mm 2 ) is the yield stress of the beam flange, σ wy (N / mm 2 ) is the yield stress of the beam web, B w (mm) is the width of the weld metal between the horizontal haunch and the beam flange at the center of the plate thickness of the beam flange. [Equation 2] [Equation 3] [Equation 4]

2. A manufacturing method of an H-shaped steel beam provided with a horizontal haunch at the end in the material axis direction, The weld metal between the horizontal haunch and the beam flange is formed by dividing the width of the horizontal haunch by a length L from the widening start position. w The grooves are continuously provided so as to extend only toward the center in the material axis direction. The length L w A manufacturing method of an H-shaped steel beam, wherein the relationship of the following formula (1) is satisfied. [Equation 5] however, L (mm) is the distance from the widening start position to the inflection point of the bending moment acting in the axial direction of the H-shaped steel beam, bf1 M p (N mm) is the full plastic bending moment of the beam flange and the weld metal at the widening start position, and is expressed by the following formula (2): bf2 M p (N mm) is the length L from the widening start position w The full plastic bending moment of the beam flange at the center position in the material axis direction is expressed by the following formula (3): bw M p (N mm) is the total plastic bending moment of the beam web, expressed by the following equation (4): D b (mm) is beam depth, B b (mm) is the beam width, t f (mm) is the thickness of the beam flange, t w (mm) is the thickness of the beam web, σ fy (N / mm 2 ) is the yield stress of the beam flange, σ wy (N / mm 2 ) is the yield stress of the beam web, B w (mm) is the width of the weld metal between the horizontal haunch and the beam flange at the center of the plate thickness of the beam flange. [Equation 6] [Equation 7] [Equation 8]

3. 3. The manufacturing method of an H-shaped steel beam according to claim 2, wherein, when welding between the beam flange and the horizontal haunch, a groove is machined on the horizontal haunch side, and a ceramic tab having the same groove shape as the groove machined on the horizontal haunch side is used to extend the groove of the horizontal haunch toward the center in the material axis direction.

4. 4. The method for manufacturing an H-shaped steel beam according to claim 2, wherein when welding between the beam flange and the horizontal haunch, an I-shaped groove having an angle of 5° or less or a V-shaped groove having an angle of 35° or less is formed on the horizontal haunch side.

Images