JP4035843B2 - Bonding structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a joined structure in which plate-like members such as reinforcing ribs are provided for various structural members.
[0002]
[Prior art]
For example, a joining structure as shown in FIGS. 18 and 19 has conventionally been used for a joining portion between a steel structural pedestal structure and a foundation. In this conventional joint structure, a base plate 11 for bolt joining is welded to an end portion of the structural member 10, and the space between the structural member 10 and the base plate 11 is reinforced by a reinforcing rib 12. The reinforcing rib 12 is a plate-like member extending in the main stress direction of the structural member 10, and protrudes in a T shape with respect to the surface of the structural member 10.
[0003]
However, in the conventional joint structure as described above, when a bending moment acts on the structural member 10, a large out-of-plane bending stress concentration occurs in the structural member 10 near the toe portion of the reinforcing rib 12, and the structural performance is deteriorated. There was a problem. Further, when the reinforcing rib 12 is welded to the structural member 10, the turning welded portion at the upper end portion of the reinforcing rib 12 is likely to become a structural defect due to the overlap between the welding heat residual stress and the heat affected member quality deterioration of the weld toe portion. There was a problem that the proof stress and fatigue performance decreased. Such a problem is common to many joint structures in which the reinforcing ribs 12 are T-welded to the structural member 10, and gussets are also included in the Japan Steel Structure Association "Fatigue Design Guidelines for Steel Structures and Explanation". As meat or groove welded joints reduce the proof stress and fatigue performance of steel members, it has been pointed out that design should be considered.
[0004]
[Problems to be solved by the invention]
The present invention solves the above-mentioned conventional problems, can remarkably reduce the stress concentration at the toe portion of a plate-like member such as a reinforcing rib, and when welding a plate-like member, Residual stress can be greatly relieved, and as a result, it was made to provide a joint structure of a structural member and a plate-shaped member that can significantly improve proof stress and fatigue performance than before. is there.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of claim 1 is a joined structure in which another plate-like member is welded to the surface of a structural member to protrude, and the plate-like member is the structure. A joint mounting reinforcing rib bent in a U-shape or V-shape along the surface of the member and protruding into a T-shape , and the center line of the entire reinforcing rib bent in the U-shape or V-shape is have unsuitable in the main stress direction of the structural member, is characterized in that the bent portion was set to be farther from the joint. In addition, the edge part of a plate-shaped member means the edge part which the plate-shaped member is in contact with the structural member which is a base material.
[0006]
The invention according to claim 2 is a joined structure in which another plate-like member is welded and protruded on the surface of the structural member, and the plate-like member is U-shaped along the surface of the structural member. Or a reinforcing rib for attaching a secondary member bent into a V shape and protruding into a T shape, and the center line of the entire reinforcing rib bent into the U shape or the V shape is a main stress direction of the structural member We suited to, it is characterized in that the bent portion was set to be farther from the secondary member.
[0007]
As described above, in the present invention, the end portion (stop end portion) of a plate-like member such as a reinforcing rib is bent in the direction of escaping from the main stress direction of the structural member to be U-shaped or V-shaped. The rigidity of the end of the member is reduced. As a result, when a load is applied to the structural member, the stress concentration in the vicinity of the plate-like member end is relieved greatly, and even when the plate-like member is welded, Welding heat residual stress can be greatly relieved. As a result, the yield strength and fatigue performance as a joined structure can be significantly improved as compared with the conventional case. Specific values will be described later. Hereinafter, preferred embodiments of the present invention will be described. In the following embodiments, the plate-like member is a reinforcing rib and protrudes from the surface of the structural member by welding.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view showing a first reference embodiment of the present invention. 1 is a structural member such as a steel pipe to be joined to each other, and 2 is a structural member 1. It is the flange for joining for the bolt joining each welded to the joining edge part. Reference numeral 3 denotes a reinforcing rib projecting in a T shape between each of the structural members 1 and the joining flange 2. In this example, the reinforcing rib 3 is T-welded. The main stress direction of the structural member 1 is the vertical direction in FIG. As shown in the drawing, these reinforcing ribs 3 are bent in a U shape along the surface of the structural member, but extend in the main stress direction of the structural member 1 as a whole. Further, the end portion (stop end portion) 4 of the reinforcing rib 3 on the side far from the joining flange 2 is gently bent in a curved line until it becomes perpendicular to the main stress direction.
[0009]
The reinforcing rib 3 is welded to the structural member 1 and is also welded to the joining flange 2. In order to perform welding reliably, it is preferable to provide a scallop at the inner corner of the reinforcing rib 3.
[0010]
In the joined structure having this structure, the end 4 of the reinforcing rib 3 is bent in a U-shape so as to escape from the main stress direction of the structural member 1, so that the end 4 of the reinforcing rib 3 has a low rigidity structure. be able to. As a result, the stress concentration at the end portion 4 of the reinforcing rib 3 is greatly relaxed, and the welding heat residual stress of the welded portion is also greatly relaxed, so that the yield strength and fatigue performance as a joined structure are greatly improved.
[0011]
In order to sufficiently exhibit this effect, it is preferable to set the radius of curvature r of the end 4 of the reinforcing rib 3 to be not less than three times the plate thickness t. If the radius of curvature r is smaller than this, material deterioration is liable to occur when the reinforcing rib 3 is bent, and the effect of reducing the rigidity is reduced.
[0012]
The joining flanges 2 of the first reference embodiment are joined by bolts 6 as in the conventional case. The number and position of the bolts 6 are not particularly limited. However, if the bolts 6 are provided inside the reinforcing ribs 3 bent in a U shape as shown in FIG. 1, they are protected from external physical impacts and corrosive environments. There are advantages to being. In any of the embodiments described below, the pipe constituting the structural member 1 is shown as a round steel pipe, but it may be a square pipe, and the structural member 1 may be made of steel mold.
[0013]
(Junction structure of structural member and base plate) In the second reference form shown in FIG. 2, the structural member 1 is a pedestal structure made of a steel pipe, and 5 is a base plate for fixing the structural member 1 to the foundation. It is. Between these structural members 1 and the base plate 5, a reinforcing rib 3 bent in a U-shape is projected in a T-shape by T-welding as in the first reference embodiment. In the embodiment of FIG. 2, the width of the reinforcing rib 3 is cut off obliquely so as to become narrower toward the end portion 4, thereby further reducing the rigidity of the end portion 4. As in the third reference embodiment shown in FIGS. 3 to 5, the position of the bolt 6 for fixing the base plate 5 to the base may be outside of the reinforcing ribs 3. 6 and 7 show modifications thereof.
[0014]
FIG. 8 shows a stress concentration diagram obtained by FEM analysis of the joint structure of the second reference embodiment, and FIG. 9 shows a stress concentration diagram of a conventional joint structure having a flat reinforcing rib. In these drawings, the generated stress distribution around the reinforcing rib 3 when a horizontal load equal to the upper end of each structural member 1 is applied is shown by contour lines, and the unit of numerical values in the drawings is MPa. From the comparison of these figures, it can be seen that the stress concentration around the reinforcing rib 3 corresponding to the present invention is greatly relaxed as compared with the prior art.
[0015]
The fourth reference embodiment shown in FIG. 10 to FIG. 12 is one in which two adjacent reinforcing ribs 3 in FIG. 3 are made continuous. Also in this example, the end 4 of the reinforcing rib 3 is bent until it becomes perpendicular to the main stress direction of the structural member 1, and the same effects as those of the other embodiments described above can be obtained.
[0016]
In the fifth reference embodiment shown in FIGS. 13 to 15, the shape of the reinforcing rib 3 provided between the structural member 1 and the base plate 5 is V-shaped. Both side portions of the reinforcing rib 3 are slightly inclined with respect to the main stress direction of the structural member 1, but the entire center line extends in the main stress direction. Other configurations and operational effects are the same as those of the other embodiments described above.
[0017]
The end 4 of the reinforcing rib 3 is preferably curved and bent as shown in the drawings, but it can also be bent linearly. Also in this case, since the end 4 of the reinforcing rib 3 has low rigidity with respect to the main stress of the structural member 1, the same effect as described above can be obtained. However, since a new stress concentration occurs in the bent portion, it is preferable to bend and bend in a curved shape.
[0018]
(Joint structure of structural member and reinforcing rib for attaching joint) In the first reference embodiment shown in FIG. 1, two structural members 1 (steel pipes) are joined using the joining flange 2, but FIG. 1 shows an example in which the reinforcing rib 3 is a steel pipe joint. In the case of adopting such a joining structure, conventionally, a flat steel pipe joint 7 is welded to the end of each steel pipe and connected with bolts or rivets, but stress concentration is also applied to the end of the steel pipe joint 7. Occurs. However, if the reinforcing rib 3 having the bent end 4 as shown in FIG. 16 is used, stress concentration can be reduced and welding heat residual stress can also be reduced. FIG. 16 shows an example in which the reinforcing rib 3 is bent in a U shape.
[0019]
(Junction structure of structural member and reinforcing rib for attaching secondary member) In addition, the present invention can also be applied to a reinforcing rib for attaching the structural member and the secondary member. This reinforcing rib is also arranged in the main stress direction of the structural member, and its upper and lower ends are bent in a U shape or a V shape in a direction of escaping from the main stress direction of the structural member. Similar to the other embodiments and the reference embodiment , the stress concentration at the end can be reduced and the welding heat residual stress can be reduced as compared with the conventional structure using the flat reinforcing rib.
[0020]
【Example】
In order to confirm the effect of the present invention described above, a fatigue strength test was performed.
Two types of specimens were produced, one corresponding to the prior art and one corresponding to the present invention. A test body corresponding to the prior art is as shown in FIG. 18, in which a steel pipe having a length of 1 m is erected on a base plate having a thickness of 22 mm, and its base portion is reinforced with a conventional vertical rib. Further, a test body corresponding to the present invention is as shown in FIG. 2, and a steel pipe having a length of 1 m is set up on a base plate having a thickness of 22 mm, and a base portion thereof is reinforced by a U-shaped reinforcing rib. The welding is all carbon dioxide arc welding, and the steel plates used are all SM400 steel.
[0021]
FIG. 17 shows the results of measuring the fatigue strength of these test specimens against the steel pipe bending load by a known method. As shown in the figure, the test body corresponding to the prior art is about G grade of the design life curve of the railway bridge design specification, whereas the test body corresponding to the present invention is equivalent to A to B grade. It was confirmed that the fatigue strength was greatly improved by adopting the structure of the present invention.
[0022]
【The invention's effect】
As described above, according to the present invention, the stress concentration at the toe portion of the plate-like member and the welding heat residual stress in the joined structure can be relieved greatly, and the yield strength and fatigue performance of the joined structure can be reduced. Can be greatly improved as compared with the prior art. Therefore the present invention is the wide range of applications as shown in the implementation form and reference embodiment can greatly contribute to the improvement of reliability.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a first reference embodiment.
FIG. 2 is a perspective view showing a second reference embodiment.
FIG. 3 is a perspective view showing a third reference embodiment.
4 is a front view of the joint structure of FIG. 3;
FIG. 5 is a plan view of the joint structure of FIG. 3;
6 is a front view of a modified example of FIG. 3. FIG.
FIG. 7 is a plan view of a modification of FIG.
8 is a stress concentration view that FEM analyzing the joined structure of the second reference embodiment.
FIG. 9 is a stress concentration diagram of a joint structure having a conventional flat reinforcing rib.
FIG. 10 is a perspective view showing a fourth embodiment.
11 is a front view of the joint structure of FIG.
12 is a plan view of the joint structure of FIG.
FIG. 13 is a perspective view showing a fifth reference embodiment.
14 is a front view of the joint structure of FIG. 13. FIG.
15 is a plan view of the joint structure of FIG.
FIG. 16 is a perspective view showing the first embodiment.
FIG. 17 is a SN curve showing the fatigue strength test results in the examples.
FIG. 18 is a perspective view showing a conventional joint structure.
FIG. 19 is a perspective view showing another conventional joint structure.

Claims (2)

A joined structure in which another plate-like member is welded and protruded on the surface of the structural member, and the plate-like member is bent in a U-shape or a V-shape along the surface of the structural member. a reinforcing rib for fitting attachment which projects into the mold, the center line of the reinforcing entire rib bent in a U-shape or V-shape is not suited to the main stress direction of the structural member, the bent portion is the A joint structure characterized in that it is located on the side far from the joint . A joined structure in which another plate-like member is welded and protruded on the surface of the structural member, and the plate-like member is bent in a U-shape or a V-shape along the surface of the structural member. a reinforcing rib for the secondary member mounting which projects into the mold, the U-shaped or the reinforcing ribs across the center line that is bent in a V shape is not suited to the main stress direction of the structural member, the curved portion Is a structure far from the secondary member .

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