JP4830498B2 - Double steel pipe brace material - Google Patents

Description

  The present invention relates to a double steel pipe brace member that is installed in a building structure and absorbs seismic energy when an earthquake occurs, and has an axial force tube and a stiffening tube that stiffens the axial force tube.

  A double steel pipe brace member has been conventionally used as a damper that is installed in a building structure and absorbs vibration energy of an earthquake when an earthquake occurs. The double steel tube brace member has a double tube structure with an axial force tube that absorbs seismic energy and a stiffening tube that stiffens the axial force tube to prevent buckling. There are a case where a stiffening tube is inserted (a stiffening tube as an inner tube) and a case where an axial force tube is inserted in a stiffening tube (a stiffening tube as an outer tube). The double steel pipe brace member increases the seismic energy that can be absorbed by the axial force tube, so that it is not only buckling over the entire length of the axial force tube but also a buckling that occurs locally in the axial force tube. Developments have been made to prevent local buckling (hereinafter referred to as local buckling) and promote the occurrence of compressive plastic deformation over the entire length of the axial force tube.

  As such a double steel pipe type brace member, in order to protect both ends to which particularly force is applied, for example, when the axial force tube is an outer tube (stiffening tube as an inner tube), both ends of the axial force tube are It is known that a local buckling is prevented by “end stiffening” which is formed by a thick steel pipe or a steel pipe material or a strip steel material is installed on both ends of an axial force pipe (for example, Patent Document 1). reference.).

Also, when the axial force tube is an inner tube (stiffening tube as an outer tube), a weld bead is built up on the outer periphery of the joint member fixed at both ends of the axial force tube, and the outer periphery of the weld bead is cut. In addition, a technique for preventing local buckling by forming a “minimum gap” by making the gap between the outer pipe and the stiffening pipe as small as possible (see, for example, Patent Document 2). .
JP-A-6-346510 Japanese Patent No. 2711994

  The “end stiffening” described in Patent Document 1 can prevent local buckling to some extent, but the strength of the stiffened axial force tube portion increases, so that compression plastic deformation occurs in the entire length of the axial force tube. There is a problem that it becomes difficult to promote. Moreover, it has the stub cone (end plate) each fixed to the both ends of the axial force pipe | tube described in patent document 1, and has a node (joint part) fixed to the stub cone. In the double steel pipe type brace member, the stub cone is relatively rigid with respect to the axial force tube. In particular, when the diameter / thickness ratio of the axial force tube is relatively large, there is a problem that local buckling tends to be induced.

  Further, in the method for preventing local buckling by forming a “minimum gap” as described in Patent Document 2, the gap between the axial force tube and the stiffening tube is minimized by a weld bead. Although the portion is short, when a double steel pipe brace member is manufactured, it is easier to manufacture when the axial force pipe is inserted into the stiffening pipe with a wide gap (for example, 5 to 10 mm). A double steel pipe brace member having a minimum clearance of 5 mm or less has a problem that the manufacturing cost increases.

  The present invention has been made in view of the above, and in a double steel tube brace member in which joints are fixed to both ends of an axial force tube, local buckling is prevented without increasing the strength of the axial force tube itself. Another object of the present invention is to provide a double steel pipe brace member that can be manufactured using conventional techniques without the need to set the gap between the axial force pipe and the stiffening pipe small.

The features of the present invention for solving such problems are as follows.
(1) An axial force tube that is installed on a structural member by cross gusset plates fixed to both ends and receives axial force, and a stiffening tube or shaft that has the axial force tube penetrating the entire inner length thereof A double steel pipe brace member that has a stiffening pipe that is housed in the entire inner length of the force pipe, and that suppresses the occurrence of buckling when axial compressive stress is applied to the axial force pipe by the stiffening pipe. A double steel pipe brace member in which a part of the cross gusset plate is inserted into both ends of the axial force pipe.
(2) In the case of having a stiffening tube through which the axial force tube penetrates, a steel ring smaller than the inner diameter of the stiffening tube is installed at the tip of the cross gusset plate on the side inserted into the axial force tube. (2) The double steel pipe brace member according to (1).
(3) When the axial force pipe has a stiffening tube that penetrates, both ends of the axial force tube are closed with a steel plate smaller than the inner diameter of the stiffening tube (1) or The double steel pipe brace member according to (2).
(4) When having a stiffening tube housed inside the axial force tube, a steel ring smaller than the inner diameter of the axial force tube is installed at the tip of the cross gusset plate on the side inserted into the axial force tube The double steel pipe brace member according to (1), characterized in that:
(5) The duplex unit according to (1) or (4), wherein both ends of the axial force tube are closed with a steel plate when having a stiffening tube accommodated inside the axial force tube. Steel pipe type brace member.

  According to the present invention, since the deformation does not concentrate on a specific portion at the tube end portion of the axial force tube of the double steel tube brace member, local buckling is less likely to be induced. By preventing the occurrence of local buckling, the occurrence of compressive plastic deformation can be promoted over the entire length of the axial force tube, so that the amount of seismic energy absorbed can be increased and the damping effect can be promoted.

  In addition, since a part of the cross gusset plate exists in the gap between the axial force tube and the stiffening tube, the axial force tube can be stiffened, and the clearance between the axial force tube and the stiffening tube can be managed. The width (allowable range) can be made relatively wide.

  Therefore, the double steel pipe brace member can be rigidly joined to the structural member without any special measures. At the same time, since the amount of seismic energy absorbed by the axial force tube itself is increased, the damping effect is promoted.

  In addition, since the gap space between the axial force tube and the stiffening tube necessary for manufacturing the double steel pipe brace member can be provided sufficiently, it is easy to insert the axial force tube into the stiffening tube. is there.

  The present inventors are an axial force tube that is installed on a structural member such as a building structure and receives axial force, and a stiffening tube that suppresses the occurrence of buckling when axial compressive stress is applied to the axial force tube. When the double steel pipe type brace member comprising cross gusset plates fixed to both ends of the axial force pipe is inserted into the end of the axial force pipe, a part of the cross gusset plate is inserted. The inventors have found that bending can be prevented and completed the present invention. The double steel pipe type brace member includes a stiffening tube (stiffening tube as an outer tube) through which an axial force tube penetrates and a stiffening tube (inner tube) accommodated inside the axial force tube. However, in any case, the present invention can be used.

  In a double steel pipe brace member having a stiffening pipe as an outer pipe, it is preferable to install a steel ring smaller than the inner diameter of the stiffening pipe at the tip of the cross gusset plate on the side inserted into the axial force pipe. It is preferable that both ends of the axial force tube are closed with a steel plate smaller than the inner diameter of the stiffening tube.

  In a double steel pipe brace member having a stiffening pipe as an inner pipe, it is preferable to install a steel ring smaller than the inner diameter of the axial force pipe at the tip of the cross gusset plate on the side inserted into the axial force pipe. It is preferable that both ends of the axial force tube are closed with a steel plate.

  An embodiment of the present invention will be described as Embodiment 1 with reference to the drawings.

  FIG. 1 is an embodiment of the present invention, and is a partial cross-sectional side view schematically showing one end portion of a double steel pipe brace member having a stiffening pipe as an outer pipe, and (a). It is sectional drawing (b) of the AA part in (embodiment 1). In the drawings, the dimensions of each part are exaggerated for the sake of clarity of structure, and the magnitude relationship is not limited to that illustrated. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and a part of the description is omitted.

  In FIG. 1, a double steel tube brace member 10 is inserted into an axial force tube 1 that receives axial force, a stiffening tube 2 in which the axial force tube 1 is inserted, and both ends of the axial force tube 1. And a cross gusset plate 4 which is a joint portion.

  As described above, the double steel pipe brace member having the conventional joint portion is formed by welding end plates (stub cones in Patent Document 1) to both ends of the axial force pipe 1 and forming connection portions on the end plates. Since it constitutes a joint, there is a problem that local buckling is likely to be induced by concentrating compressive plastic deformation on the axial force tube portion near the boundary between the end plate and the axial force tube. A joint portion is configured by inserting a cross gusset plate to both ends of the axial force tube 1 for a predetermined length. For example, the cross gusset plate 4 can be inserted into the axial force tube 1 by forming four cuts corresponding to the insertion length at both ends of the axial force tube 1.

  The cross gusset plate 4 is made of a steel plate, and the end of the cross gusset plate 4 is inserted to a predetermined range of the axial force tube 1. The insertion portion of the cross gusset plate 4 is welded to the axial force tube 1. As a result, the transmission of the force between the axial force tube 1 and the cross gusset plate 4 is not concentrated only on the end portion, and the force can be dispersed and transmitted at the insertion portion of a predetermined length. Local buckling is prevented because deformation becomes difficult to concentrate. In addition, out-of-plane deformation perpendicular to the tube axis (for example, enlargement of the diameter in a circular shape or ovalization in which the circumference is extended) is less likely to occur.

  Therefore, even when the building structure is deformed when an earthquake occurs and axial compression force and bending are applied to the axial force tube 1, the axial force tube 1 is supported by the stiffening tube 2 in the tube axial direction and the circumferential direction. Because it is stiffened and stress does not concentrate only at both ends of the axial force tube 1, local buckling is less likely to occur, and compression is achieved over a wide range of the axial force tube 1 (the same as the long axial range). Plastic deformation occurs and seismic energy can be sufficiently absorbed.

  In addition, since the double steel pipe brace member of the present invention is unlikely to be locally buckled, even if the double steel pipe brace member is manufactured by making the thickness of the axial force pipe 1 thinner than before, the predetermined vibration damping is achieved. It becomes possible to demonstrate performance.

  The shape of the cross gusset plate 4 is not limited to that shown in FIG. 1, and the attachment method to the axial force tube 1 may be mainly performed by welding, but is not limited to this method.

  A steel ring 5 smaller than the inner diameter of the stiffening tube 2 may be attached to the distal end portion (insertion distal end portion) of the cross gusset plate 4. The force at the tip of the cross gusset plate 4 is dispersed, and the force transmission between the axial force tube 1 and the cross gusset plate 4 becomes smoother.

  Further, since the local buckling is likely to be induced when the diameter-thickness ratio of the axial force tube 1 is large, a tube end in which both ends of the axial force tube 1 are formed of steel plates smaller than the inner diameter of the stiffening tube 2 as necessary. When the lid 6 is closed, it is possible to prevent the axial force tube 1 from being enlarged or elliptical.

  Further, the size of the gap between the axial force tube 1 and the stiffening tube 2 is such that the operation of inserting the axial force tube 1 into the stiffening tube 2 is possible, and the axial force tube 1 is plastically deformed in a wave shape (axisymmetric). The same as plastic deformation).

  Furthermore, the surface of the cross gusset plate 4 may be subjected to an unbonding process in order to reduce friction with the inner peripheral surface of the stiffening tube.

  The axial force pipe 1 is preferably a steel pipe made of a low yield point steel material, and the stiffening pipe 2 is preferably a steel pipe having a tensile strength of STK400 or higher.

  The cross gusset plate 4 is abutted against the cross gusset plate installed in the building structure and joined via a splice plate. At this time, a connecting bolt is inserted into the through hole 41 provided in the cross gusset plate 4. Alternatively, the “mounting plate” may be fixed to the end of the cross gusset plate 4, the mounting plate may be fixed to the building structure, abutted against the installation plate, and the two may be joined by bolts.

  Furthermore, the joining means with the building structure in the present invention is not limited, and pin joining may be performed.

  Further, a stopper (not shown) can be provided so that the stiffening tube 2 does not come out of the axial force tube 1. Although it is desirable to provide a means for preventing slipping out, it is not limited to the stopper, and a part of the stiffening tube 2 and the axial force tube 1 may be connected.

Below, an example of the manufacturing method of the double steel pipe type brace member 10 is demonstrated. The procedure for inserting the cross gusset plate 4 includes a step of inserting the cross gusset plate 4 at the end of the axial force tube 1 and a step of welding the axial force tube 1 and the cross gusset plate 4. More specifically, the following steps (a) to (c) are performed.
(A) The end portion of the axial force tube 1 is cut according to the shape of the cross gusset plate 4 to be inserted.
(B) The cross gusset plate 4 is inserted into the axial force tube cutting portion.
(C) Then, the cross gusset plate 4 is flare welded to the axial force tube using a semi-automatic carbon dioxide arc welding or the like.

  Note that the optimum insertion length of the cross gusset plate 4 can be obtained from the conditions that can secure an effective weld cross-section where the welded portion does not break even at the maximum proof stress of the axial force pipe.

  After the cross gusset plate 4 is attached to the axial force tube 1, the axial force tube 1 is inserted into the stiffening tube 2 and manufactured in the same manner as a normal double steel pipe brace member. The stiffening tube 2 and the axial force tube 1 are preferably plug welded at the center of the material.

  Next, another embodiment of the present invention will be described as a second embodiment.

  FIG. 2 is another embodiment of the present invention, and is a partial cross-sectional side view schematically showing a double steel pipe brace member having a stiffening pipe as an inner pipe, and A in FIG. It is sectional drawing (b) of -A part (Embodiment 2).

  In FIG. 2, the double steel pipe brace member 20 includes an axial force pipe 1 that receives an axial force, and the stiffening pipe 2 is accommodated inside the axial force pipe 1. The stiffening tube 2 has two parts, and the stiffening tube 2a is inserted into a part of the stiffening tube 2b. It has a cross gusset plate 4 that is a joint portion inserted into both ends of the axial force tube 1 and the end of the stiffening tube 2.

  The cross gusset plate 4 is made of a steel plate, and the end of the cross gusset plate 4 is inserted to a predetermined range of the axial force tube 1 and the stiffening tube 2. The insertion portion of the cross gusset plate 4 is welded to the axial force tube 1 and the stiffening tube 2. As a result, the transmission of the force between the axial force tube 1 and the cross gusset plate 4 is not concentrated only on the end portion, and deformation is less likely to be concentrated on a specific portion, so that local buckling is prevented. There is an effect.

  A steel ring 5 may be attached to the tip portion (insertion tip portion) of the cross gusset plate 4. The force at the tip of the cross gusset plate 4 is dispersed, and the force transmission between the axial force tube 1 and the cross gusset plate 4 becomes smoother.

  Further, since the local buckling is likely to be induced when the diameter-thickness ratio of the axial force tube 1 is large, a tube end in which both ends of the axial force tube 1 are formed of steel plates smaller than the inner diameter of the stiffening tube 2 as necessary. When the lid 6 is closed, it is possible to prevent the axial force tube 1 from being enlarged or elliptical.

  A test for confirming the performance of the cross gusset plate portion of the double steel pipe brace member (Embodiment 1) shown in FIG. 1, which is an embodiment of the present invention, was performed. FIG. 3 shows a side view of a partial cross section of the test specimen subjected to the test.

In FIG. 3, a double steel pipe brace member 30 (hereinafter referred to as “test body 30”) subjected to the test has an axial force pipe 1 having an outer diameter of 190.7 mm, a thickness of 6.0 mm, and a length of 707 mm (of which 100 N / mm class ² low yield point steel pipe (manufactured by JFE Steel Co., Ltd., trade name “RIVERFLEX100-S”, RF100-S), and the stiffening pipe 2 is It is a steel pipe having an outer diameter of 250.0 mm, a thickness of 6.0 mm, a length of 707 mm, and STK400.

  The cross gusset plate 4 is a 12 mm thick, 400 mm × 210 mm rectangular plate, one SS400, and a 12 mm thick, 400 mm × 109 mm rectangular plate, two SS400. In addition, a steel plate of the grip portion 42 to be attached to the testing machine is fixed to the end portion of the cross gusset plate 4.

  FIG. 4 is a side view of a partial cross section showing the shape of the comparative test specimen 31 produced for comparison with the test specimen 30. The axial force tube 1 and the cross gusset plate 4 are joined via an end plate 3 welded to the end of the axial force tube 1. The end plate 3 is a circular steel plate having a thickness of 32 mm, an outer diameter of 210 mm, and SN490C.

  In order to insert the cross gusset plate 4, the test body 30 cuts the end portion of the axial force tube 1 with a width of 14 mm and a length of 137 mm in accordance with the shape of the cross gusset plate 4 to be inserted. The cross gusset plate 4 was inserted into the tube cutting portion, and the cross gusset plate 4 was manufactured by flare welding to the axial force tube by semi-automatic carbon dioxide arc welding. The test body 31 was manufactured by completely penetrating and welding the end plate 3 having the cross gusset plate 4 welded to the end of the axial force tube 1 by semi-automatic carbon dioxide arc welding.

  The grip portions 42 fixed to both ends of the test body 30 were coupled to the force applying device. An axial compressive force was applied to the axial force tube 1 by the applying device. The comparative test body 31 was similarly tested. The measured stress-strain diagram is shown in FIG.

  In FIG. 5, the vertical axis represents the stress generated in the axial force tube (calculated value obtained by dividing the applied load by the cross-sectional area of the axial force tube 1). Further, the horizontal axis represents the skewness obtained by dividing the elongation of the distance between the gauge points provided on the cross gusset plate 4 by the initial length.

  According to the result of the test body 30 shown in FIG. 5 as an example of the present invention, the compressive force is applied to the axial force tube 1 and the compression yields, and the plastic deformation progresses while slightly increasing the yield strength. At the degree of skewness “a”, the increase in stress stopped and the axial force tube 1 buckled.

  On the other hand, for the comparative specimen 31 shown as a comparative example in FIG. 5, the axial force tube 1 showed the same behavior as the specimen 30 and a stress-strain curve according to the specimen 30 was drawn. However, local buckling was initiated at stage “a” with a 5% skewness.

  From the above test results, the occurrence of buckling of the axial force tube 1 can be delayed by joining the cross gusset plate 4 to the axial force tube 1 with a predetermined length without using the end plate 3. It was shown that the effect of is remarkable.

It is the side view (a) of a partial cross section which shows typically a double steel pipe type brace member (stiffening pipe as an outer pipe), and a cross section (B) of an AA portion. (Embodiment 1) It is the side view (a) of a partial cross section which shows typically a double steel pipe type brace member (stiffening pipe as an inner pipe), and a cross section (B) of an AA portion. (Embodiment 2) The side view of the partial cross section of the test body of Embodiment 1. FIG. The side view of the partial cross section of the comparative test body of Embodiment 1. FIG. The stress-strain diagram of a test body and a comparative test body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axial force pipe 2 (2a, 2b) Stiffening pipe 3 End plate 4 Cross gusset plate 5 Steel ring 6 Pipe end cover 10 Double steel pipe type brace member (Embodiment 1)
20 Double steel pipe brace member (Embodiment 2)
30 Double steel pipe brace member (test body)
31 Double steel pipe brace member (Comparative specimen)
41 Through hole 42 Grab

Claims (5)

An axial force tube that is installed on a structural member by cross gusset plates fixed to both ends and receives an axial force, and a stiffening tube in which the axial force tube penetrates the entire inner length of the axial force tube or the axial force tube and a stiffening tube which is housed within the overall length, the axial compressive stress to the axial force tube is a double steel type bracing member suppress by the stiffening tube the occurrence of buckling at the time of acting, A double steel pipe brace member in which a part of the cross gusset plate is inserted into both ends of the axial force pipe.   When there is a stiffening tube through which the axial force tube penetrates, a steel ring smaller than the inner diameter of the stiffening tube is installed at the tip of the cross gusset plate on the side inserted into the axial force tube. The double steel pipe brace member according to claim 1.   3. When the axial force pipe has a stiffening pipe penetrating therethrough, both ends of the axial force pipe are closed with a steel plate smaller than the inner diameter of the stiffening pipe. A double steel pipe brace member as described in 1.   If you have a stiffening tube housed inside the axial force tube, install a steel ring smaller than the inner diameter of the axial force tube at the tip of the cross gusset plate that is inserted into the axial force tube. The double steel pipe brace member according to claim 1, wherein 5. The double steel pipe brace according to claim 1, wherein both ends of the axial force pipe are closed with a steel plate when having a stiffening pipe accommodated inside the axial force pipe. Element.

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