JP2004044100A - Beam structure and beam end widening method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a beam structure and a beam end widening method for fixing a horizontal rib plate to a flange with a small amount of welding. <P>SOLUTION: Double bevel groove machining is performed for a welding surface 10 of the horizontal rib plate 9 to a flange 7 with a non-welding part 27 left in the center thereof. The thickness of the non-welding part 27 is calculated as in the following. In the tip 13 of the horizontal rib, the state where the H-steel 5 reaches a bending strength M<SB>u</SB>, that is, the state where the right stress intensity σ<SB>2</SB>of the flange 7 reaches tensile strength σ<SB>u</SB>is<SB></SB>set to calculate the right stress intensity σ<SB>1</SB>at the beam end 11 according to a gradient 23 of moment diagram 21 of the beam 3. Supposing that the right stress strength P<SB>1</SB>of the horizontal rib plate 9 at the beam end 11 is transmitted by shear force between the horizontal rib plate 9 and the flange 7, the thickness of the non-welding part 27 is calculated so that the shearing stress strength τis below the final shearing strength τ<SB>u</SB>. The beveled horizontal rib plate 9 is fixed to the flange 7 of the H-steel 5 by welding 15 to form the beam 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a beam structure and a beam end widening method.
[0002]
[Prior art]
Conventionally, in order to prevent brittle rupture at the joint of a steel pipe column and an H-shaped steel beam during an earthquake, (1) a method of widening the flange at the end of the beam by cutting a plate, (2) welding a reinforcing horizontal rib plate A method of widening the flange at the end of the beam by using a beam is used. The methods (1) and (2) are a method of cutting a web and a flange from a flat plate and welding them, respectively, to form a H-shaped steel material of a built material type, a rolling process at a steel mill, and a build-up at a processing plant. It can be used for any of the roll material type H steel formed into the H shape in the process.
[0003]
FIG. 10 is a plan view of the beam 107 whose end is widened by the method (1), that is, plate cutting. In FIG. 10, H steel 103 whose end is widened is used as beam 107. When a build material type H steel is used, the H steel 103 is formed by cutting and welding a web and a flange 105 whose ends are widened from a flat plate. When a roll material type H steel is used, the H steel 103 is formed by cutting a flange like a flange 105. The end of the beam 107 is joined to the column 101.
[0004]
FIG. 11 is a plan view of the beam 117 in which the end is widened by welding the reinforcing horizontal rib plate by the method (2). FIG. 12 is a sectional view taken along line FF of FIG. In FIG. 11, an H steel 113 having a horizontal rib plate 119 fixed to an end of a flange 115 is used as a beam 117.
[0005]
As shown in FIG. 12, the side face of the horizontal rib plate 119 is grooved. The horizontal rib plate 119 is, for example, beveled into a K-shape, a re-shape, or the like so that the shear stress τ of the welding surface with the flange 115 is within the elastic range, and both sides of the end of the flange 115 by welding 121. Fixed to At this time, the flange 115 and the rib plate 119 are completely melted and integrated. The end of the beam 117 is joined to the pillar 111.
[0006]
The method (2) is often applied to a roll material type H steel that is often used as a beam. Even in the case of a built-in type H steel, the method (2) may be more economical and simpler in the manufacturing process.
[0007]
[Problems to be solved by the invention]
However, in the method (2), since the horizontal rib plate 119 and the flange 115 are welded so as to be completely integrated, when the flange 115 is thick, the amount of welding increases and the cost increases. Further, the horizontal rib plate 119 is likely to be warped or twisted due to heat at the time of welding. Further, there is a risk that the beam section near the rib tip 123, which should exhibit a stable behavior, may cause brittle fracture at an early stage due to the influence of welding heat.
[0008]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a beam structure and a beam end widening method capable of fixing a horizontal rib plate to a flange with a small amount of welding.
[0009]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a beam structure in which a horizontal rib plate is welded to a side surface of a flange near an end of an H steel beam. Then, when the H steel beam reached the bending strength, the horizontal rib plate was grooved so that the average shear stress degree of the welding surface with the flange of the horizontal rib plate was not more than the ultimate shear strength. A beam structure characterized by the following.
[0010]
The groove shape of the horizontal rib plate is a uniform K groove. When the H steel beam reaches the bending strength at the tip of the rib, that is, at the end of the horizontal rib plate on the beam center side, the thickness of the welding residue of the horizontal rib plate is determined by the thickness of the welding surface with the flange of the horizontal rib plate. It is calculated so that the average shear stress is within the ultimate shear strength.
[0011]
In the first invention, when the H steel beam reaches the bending strength at the end of the horizontal rib plate on the beam center side, the average shear stress of the welding surface with the flange of the horizontal rib plate is equal to or less than the ultimate shear stress. The groove processing of the horizontal rib plate is performed so that
[0012]
A second invention is a beam structure in which a horizontal rib plate is welded to a side surface of a flange near an end of an H-steel beam, and the thickness of the unwelded portion is changed from the end of the horizontal rib plate on the beam center side to the beam end. The horizontal rib plate is beveled so as to decrease toward a side end.
[0013]
The groove shape of the horizontal rib plate is a uniform K groove. When the H steel beam reaches the bending strength at the tip of the rib, that is, at the end of the horizontal rib plate on the beam center side, for example, the area of the welding residue of the horizontal rib plate is welded to the flange of the horizontal rib plate. Is equal to the area of the remaining welding residue calculated so that the average shear stress degree of the specimen becomes equal to or less than the ultimate shear strength. The gradient of the welding residue from the end on the beam center side to the end on the beam end side is, for example, proportional to the moment gradient of the beam.
[0014]
In the second invention, the horizontal rib plate is beveled so that the thickness of the unwelded portion decreases from the end on the beam center side of the horizontal rib plate toward the end on the beam end side.
[0015]
A third invention is a beam structure in which a horizontal rib plate is welded to a side surface of a flange near an end of an H steel beam, and an end tab is fixed to an end of the horizontal rib plate on the beam center side. It is a characteristic beam structure.
[0016]
The end tab is fixed to the horizontal rib plate and the flange by welding. The end tab is made of a weldable material such as steel.
In the third invention, an end tab is fixed to the end of the horizontal rib plate on the beam center side.
[0017]
A fourth invention is a beam end widening method of welding a horizontal rib plate to a side surface of a flange near an end of an H-steel beam, wherein the H-steel beam is located at an end position on the beam center side of the horizontal rib plate. (A) performing the groove processing of the horizontal rib plate so that when the bending strength is reached, the average shear stress degree of the welding surface of the horizontal rib plate with the flange is not more than the ultimate shear strength. A method for widening a beam end, comprising a step (b) of welding a horizontal rib plate and the flange.
[0018]
A fourth invention is a beam end widening method for forming the beam structure of the first invention. The groove shape of the horizontal rib plate is a uniform K groove.
In the fourth invention, when the H steel beam reaches the bending strength at the end position on the beam center side of the horizontal rib plate, the average shear stress of the welding surface with the flange of the horizontal rib plate is not more than the ultimate shear stress. The groove processing of the horizontal rib plate is performed so that Then, the horizontal rib plate and the flange are welded.
[0019]
A fifth invention is a beam end widening method for welding a horizontal rib plate to a flange side surface near an end of an H steel beam, wherein the thickness of the unwelded beam is measured from the end of the horizontal rib plate on the beam center side. And (b) welding the horizontal rib plate and the flange so as to reduce the width toward the end. This is the characteristic beam end widening method.
[0020]
A fifth invention is a beam end widening method for forming the beam structure of the second invention. The groove shape of the horizontal rib plate is a uniform K groove.
In the fifth invention, the groove processing of the horizontal rib plate is performed so that the thickness of the unwelded portion decreases from the end on the beam center side of the horizontal rib plate toward the end on the beam end side. Then, the horizontal rib plate and the flange are welded.
[0021]
A sixth invention is a beam end widening method of welding a horizontal rib plate to a side surface of a flange near an end of an H steel beam, wherein a step of fixing an end tab to an end of the horizontal rib plate on the beam center side is included. A beam end widening method characterized by comprising:
[0022]
A sixth invention is a beam end widening method for forming the beam structure of the third invention. The end tab is fixed to the horizontal rib plate and the flange by welding. The end tab is made of a weldable material such as steel.
In the sixth invention, the end tab is welded to the horizontal rib plate and the flange.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view of a joint between the column 1 and the beam 3, FIG. 2 is a vertical cross-sectional view of the beam 3, and FIG. 3 is a perspective view near the horizontal rib plate 9. FIG. 2 is a sectional view taken along the line AA of FIG. FIG. 3 is a perspective view taken along line BB of FIG.
[0024]
As shown in FIGS. 1 and 2, the beam 3 is made up of an H steel 5, a horizontal rib plate 9, and the like. Horizontal rib plates 9 are fixed to both side surfaces 8 of the flange 7 near the end of the H steel 5. The H steel 5 is, for example, a roll material type H steel. The horizontal rib plate 9 is, for example, a rectangular steel plate. As shown in FIGS. 2 and 3, the welding surface 10 of the horizontal rib plate 9 is subjected to a K-shaped beveling process in which both corners are dropped while leaving a strip-shaped welding residue 27 at the center. The included angle is, for example, about 45 ° to 60 °.
[0025]
In the first embodiment, the beam 3 is formed by fixing the horizontal rib plate 9 having a uniform K groove to the side surface 8 of the flange 7 of the H steel 5 by welding 15. For example, a ceramic tab is used to stop welding at the horizontal rib tip 13. Then, the beam end 11 of the beam 3 is welded to the column 1. The column 1 is, for example, a steel-framed rectangular steel tube column or the like.
[0026]
The width of the welding residue 27 shown in FIG. 3 is calculated as follows.
A moment (M) having a gradient 23 is generated in the beam 3 as shown in the moment diagram 21 of the beam 3 in FIG. First, to set a state in which the moment 22 of the flange 7 at the position of the horizontal rib tip 13 has reached the bending strength M _u of steel H 5. In this case, if the normal stress of the flange 7 at the position of the horizontal rib tip 13 and sigma _2, the σ _{2 =} σ _u.
[0027]
Next, the degree of direct stress σ ₁ of the flange 7 at the beam end 11 is calculated using σ ₂ = σ _u according to the gradient 23 of the moment diagram 21 of the beam 3 shown in FIG. Then, the normal stress P ₁ of the horizontal rib plate 9 at the beam end 11 is calculated using equation (1). However, _{b h} are the width 26 of the horizontal rib plate 9 (FIG. 3), _{t f} represents a thickness 25 (FIG. 3) of the horizontal rib plate 9.
[0028]
P ₁ = σ ₁ × b _h × t _f (1)
[0029]
Then, assuming that the normal stress P ₁ is transmitted by shearing force between the horizontal rib plate 9 and the flange 7, determining the shear stresses τ welding surface of the flange 7 of the horizontal rib plate 9 using Equation (2). Here, l is the length 17 from the beam end 11 to the moment 0 (FIG. 1), λl is the haunch length 19 (FIG. 1), α is the length of about twice the fillet size, c is Represents the thickness of the welding residue 27 (FIG. 3).
[0030]
τ = P ₁ / (λl−α) (t _f −c) (2)
[0031]
Finally, the thickness c of the remaining welding portion 27 is adjusted so that the shear stress degree τ of the welding surface of the horizontal rib plate 9 with the flange 7 is equal to or less than the ultimate shear strength τ _u (= σ _u / ^31/2 ). Ask.
[0032]
In this way, welding 15 is performed with the remaining welding 27 provided so that the shear stress τ between the horizontal rib plate 9 and the flange 7 is equal to or less than the ultimate shear strength τ _u (= σ _u / ^31/2 ). Thus, the welding amount can be reduced to 50% and 25%, respectively, as compared with the conventional case where the horizontal rib plate 9 and the flange 7 are completely melted and welded at the K groove and the groove. Further, compared with the case where the K groove and the groove are processed and welded so that the shear stress degree τ of the welding surface of the horizontal rib plate 9 with the flange 7 is within the elastic range, the welding amount is 60 times each. %, 30%.
[0033]
In the first embodiment, by reducing the amount of welding 15 between the flange 7 and the horizontal rib plate 9, the thermal effect of the flange 7 of the beam 3 due to welding can be reduced, and the beam 3 at the horizontal rib tip 13 can be reduced. Premature brittle fracture can be prevented.
[0034]
In addition, the horizontal rib plate 9 is less likely to warp or twist. Furthermore, if the plate thickness of the flange 7 and the horizontal rib plate 9 is about 25 mm or less, welding can be performed in one pass in many cases, and welding can be easily performed.
[0035]
Next, a second embodiment will be described. FIG. 4 is a perspective view near the horizontal rib plate 9a. In the second embodiment, a horizontal rib plate 9 a shown in FIG. 4 is fixed to the H steel 5 instead of the horizontal rib plate 9 of the first embodiment. FIG. 4 corresponds to FIG. 3 of the first embodiment, that is, a perspective view along BB in FIG. The horizontal rib plate 9a is, for example, a rectangular plate-shaped steel plate.
[0036]
5 and 6 are vertical sectional views of the horizontal rib plate 9a. FIG. 5 is a sectional view taken along line CC of FIG. 4, and FIG. 6 is a sectional view taken along line DD of FIG. As shown in FIG. 4, a K-shaped beveling process is performed on the welding surface 10a of the horizontal rib plate 9a with the flange 7 so as to leave both corners 27a at the center and reduce both corners. The included angle is, for example, about 45 ° to 60 °.
[0037]
However, as shown in FIGS. 4 to 6, in the horizontal rib plate 9a, the thickness of the unwelded portion 27a decreases from the horizontal rib tip 13a side to the beam end 11 side, and the amount of the weld 15a increases. In the second embodiment, the beam 3 is formed by fixing the grooved horizontal rib plate 9a to the flange 7 of the H steel 5 by welding 15a. For example, a ceramic tab is used to stop welding at the horizontal rib tip 13a. Then, the beam end 11 of the beam 3 is welded to the column 1.
[0038]
When using the horizontal rib plate 9a having the same thickness, width and length as the horizontal rib plate 9 of the first embodiment, the area of the unwelded portion 27a is, for example, equal to the area of the unwelded portion 27 of the horizontal rib plate 9. And In the second embodiment, when the H steel 5 reaches the bending strength at the position of the horizontal rib tip 13a, the shear stress on the welding surface of the horizontal rib plate 9a with the flange 7 is not more than the ultimate shear stress. The area of the remaining welding 27a is calculated using the calculated thickness c of the remaining welding.
[0039]
The gradient 28 of the thickness of the unwelded portion 27a is set, for example, so as to be proportional to the gradient 23 (FIG. 1) of the moment of the beam 3 between the horizontal rib tip 13a and the beam end 11.
[0040]
In the second embodiment, similarly to the first embodiment, by reducing the amount of welding 15a between the flange 7 and the horizontal rib plate 9a, the thermal effect on the flange 7 of the beam 3 due to welding can be reduced. In addition, early brittle fracture of the beam 3 at the horizontal rib tip 13a can be prevented.
[0041]
In addition, the horizontal rib plate 9a is less likely to warp or twist. Furthermore, if the plate thickness of the flange 7 and the horizontal rib plate 9a is about 25 mm or less, welding can be performed in one pass in many cases, and welding can be easily performed.
[0042]
Further, the total welding amount is equal to that of the first embodiment, but the thickness of the unwelded portion 27a is reduced from the horizontal rib end 13a toward the beam end 11, thereby being most important for the proof strength and deformation performance of the beam 3. The amount of welding at the horizontal rib tip 13a can be further reduced.
[0043]
In the second embodiment, the thickness of the unwelded portion 27a may be reduced from the horizontal rib end 13a toward the beam end 11 while maintaining the conventional welding amount. Also in this case, the amount of welding at the horizontal rib tip 13a can be reduced as compared with the conventional case.
[0044]
In the first and second embodiments, the degree of direct stress of the flange 7 at the horizontal rib tip 13 (13a) is set to σ ₂ = σ _u when calculating the thickness of the unwelded portion 27 (27a). However, when it is clearly confirmed that σ ₂ does not reach σ _u , for example, σ ₂ is a local buckling strength (sσ _y , where s is a local buckling value) which is a value smaller than σ _u. Even if the thickness of the unwelded portion 27 (27a) is calculated so that the average shear stress degree of the welding surface of the flange 7 with the horizontal rib plate 9 (9a) becomes equal to or less than τ _u when the proof stress rise rate) is reached. Good. In this case, the welding amount can be further reduced as compared with setting the degree of direct stress as σ ₂ = σ _u .
[0045]
Further, in the first and second embodiments, the ceramic tab is used for stopping the welding at the horizontal rib tip 13 (13a), but a method such as a steel tab, a natural stopping, turning welding, or the like may be used. The H steel 5 may be a built-in type H steel.
[0046]
Next, a third embodiment will be described. 7 is a perspective view of the vicinity of the joint between the column 1 and the beam 3, FIG. 8 is a plan view of the joint between the column 1 and the beam 3, and FIG. 9 is a vertical view of the weld between the flange 7 and the horizontal rib plate 9 (9a). It is sectional drawing of a direction. FIG. 9 is a sectional view taken along line EE of FIG.
[0047]
As shown in FIGS. 7 to 9, in the third embodiment, the horizontal rib plate 9 (9 a) is fixed and the beam 3 whose end is widened has a horizontal rib end 13 of the horizontal rib plate 9 (9 a). Along with (13a) and the flange 7, an end tab 29 having a rectangular plate shape or the like is installed. The end tab 29 is fixed to the flange 7 by welding 31 and to the horizontal rib plate 9 (9a) by welding 33. The H steel 5 is, for example, a roll material type H steel, and the horizontal rib plate 9 (9a) is, for example, a rectangular plate-shaped steel plate. The end tab 29 is made of a weldable material, for example, steel.
[0048]
In the third embodiment, the grooved horizontal rib plate 9 (9a) is arranged on both sides of the flange 7 at the end of the beam 3, and the horizontal rib tip 13 (13a) is formed by welding 31 and welding 33. The end tab 29 is fixed to the flange 7. Then, the horizontal rib plate 9 (9a) is fixed to the flange 7 by welding 15, and the beam 3 is formed. Further, the beam end 11 of the beam 3 is welded to the column 1.
[0049]
Alternatively, the end tab 29 is temporarily fixed to the horizontal rib tip 13 (13a), the horizontal rib plate 9 (9a) is fixed to the flange 7 by welding 15, and the horizontal rib tip 13 (13a) is welded by welding 31 and welding 33. The end tab 29 is fixed to the flange 7.
[0050]
The horizontal rib plate, for example, calculates the thickness of the remaining welding in the same manner as the horizontal rib plate 9 of the first embodiment, and is processed into a uniform K groove as shown in FIG. Alternatively, similarly to the horizontal rib plate 9a according to the second embodiment, the thickness of the unwelded portion may be changed to form a uniform K groove. Alternatively, the groove processing may be performed with other shapes and angles.
[0051]
As described above, by using the end tab 29 to perform the welding 15 between the horizontal rib plate 9 (9a) and the flange 7, it is possible to prevent the defect of the welding 15 at the horizontal rib tip 13 (13a), and furthermore, to perform the welding. By fixing the horizontal rib plate 9 (9 a) and the flange 7 to the horizontal rib plate 9 (9 a) and the flange 7 by welding 31 and welding 33, it is possible to prevent the horizontal rib plate 9 (9 a) from being warped or twisted after welding 15.
[0052]
When the groove processing is performed in the same manner as in the first and second embodiments, the horizontal rib plate 9 and the flange 7 are compared with a case where the horizontal rib plate 9 and the flange 7 are completely melted and welded at the K groove and the groove. Thus, the amount of welding can be reduced.
[0053]
In the first to third embodiments, the horizontal rib plate 9 (9a) has a rectangular plate shape, but the shape of the horizontal rib plate is not limited to this. The shape, width, length, and the like of the horizontal rib plate are appropriately determined by a conventionally used method.
[0054]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a beam structure and a beam end widening method capable of fixing a horizontal rib plate to a flange with a small welding amount.
[Brief description of the drawings]
FIG. 1 is a plan view of a joint between a column 1 and a beam 3. FIG. 2 is a vertical cross-sectional view of the beam 3. FIG. 3 is a perspective view around a horizontal rib plate 9. FIG. FIG. 5 is a vertical cross-sectional view of the horizontal rib plate 9a. FIG. 6 is a vertical cross-sectional view of the horizontal rib plate 9a. FIG. 7 is a perspective view of the vicinity of the joint between the column 1 and the beam 3. FIG. FIG. 9 is a plan view of a welded portion between the flange 7 and the horizontal rib plate 9 in a vertical direction. FIG. 10 is a plan view of a beam 107 whose end is widened by cutting a plate. FIG. 12 is a plan view of a beam 117 whose end is widened by welding a reinforcing horizontal rib plate. FIG. 12 is a sectional view taken along line FF of FIG.
1 ... pillar 3 ... beam 5 ... H steel 7 ... flange 9, 9a ... horizontal rib plate 13 ... horizontal rib tips 15, 15a, 31, 33 ... welding 23, 28 ... gradient 27, 27a ... welding residue

Claims (12)

A beam structure in which a horizontal rib plate is welded to a flange side near an end of an H steel beam,
At the end position of the horizontal rib plate on the beam center side, when the H steel beam reaches the bending strength, the average shear stress degree of the welding surface with the flange of the horizontal rib plate is not more than the ultimate shear strength. A beam structure, wherein the horizontal rib plate is grooved. The beam structure according to claim 1, wherein a groove shape of the horizontal rib plate is a uniform K groove. A beam structure in which a horizontal rib plate is welded to a flange side near an end of an H steel beam,
A beam structure, wherein the horizontal rib plate is grooved so that the thickness of the unwelded portion decreases from the end of the horizontal rib plate on the beam center side toward the end of the horizontal rib plate on the beam end side. The beam structure according to claim 3, wherein the groove shape of the horizontal rib plate is a uniform K groove. A beam structure in which a horizontal rib plate is welded to a flange side near an end of an H steel beam,
An end tab is fixed to an end of the horizontal rib plate on the center side of the beam. The beam structure according to claim 5, wherein the end tab is welded to the horizontal rib plate and the flange. A beam end widening method of welding a horizontal rib plate to a side surface of a flange near an end of an H steel beam,
At the end position of the horizontal rib plate on the beam center side, when the H steel beam reaches the bending strength, the average shear stress degree of the welding surface with the flange of the horizontal rib plate is not more than the ultimate shear strength. (A) performing a groove processing of the horizontal rib plate;
Welding the horizontal rib plate and the flange (b);
A beam end widening method, comprising: The beam end widening method according to claim 7, wherein the groove shape of the horizontal rib plate is a uniform K groove. A beam end widening method of welding a horizontal rib plate to a side surface of a flange near an end of an H steel beam,
(A) performing a groove process on the horizontal rib plate so that the thickness of the unwelded portion decreases from an end of the horizontal rib plate on the beam center side toward an end of the horizontal rib plate on the beam end side;
Welding the horizontal rib plate and the flange (b);
A beam end widening method, comprising: The beam end widening method according to claim 9, wherein the groove shape of the horizontal rib plate is a uniform K groove. A beam end widening method of welding a horizontal rib plate to a side surface of a flange near an end of an H steel beam,
A beam end widening method, comprising a step of fixing an end tab to an end of the horizontal rib plate on the beam center side. The beam end widening method according to claim 11, wherein the end tab is welded to the horizontal rib plate and the flange.

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