JP2007186894A - Double steel-pipe type brace member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double steel-pipe type brace member capable of preventing an axial force pipe from being locally buckled when a bending force is applied to the axial force pipe and eliminating the need of setting small the gap between the axial force pipe and an auxiliary rigid pipe. <P>SOLUTION: The double steel-pipe type brace member 10 comprises an axial force pipe 1 installed on a building structure and receiving an axial force and an auxiliary rigid pipe 2 into which the axial force pipe is inserted. The brace member suppresses the occurrence of buckling when an axial compressive stress acts on the axial force pipe by the auxiliary rigid pipe. The auxiliary rigid pipe 5 is inserted into the axial force pipe. The double steel-pipe type brace member comprises an axial force pipe installed on the building structure and receiving an axial force and an auxiliary rigid pipe inserted into the axial force pipe. The brace member suppresses the occurrence of buckling when an axial compression stress acts on the axial force pipe by the auxiliary rigid pipe. The brace member has the auxiliary rigid pipe into which the axial force pipe is inserted. <P>COPYRIGHT: (C)2007,JPO&INPIT

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.

  Brace type dampers that are installed in building structures and absorb seismic energy in the event of an earthquake, used as diagonal materials for structural members such as steel structures, have axial forces that absorb seismic energy. In order to prevent the tube from buckling, a double steel tube brace member having a double tube structure by installing a stiffening tube outside or inside the axial force tube has been used conventionally. The double steel pipe brace member increases the seismic energy that can be absorbed by the axial force pipe, so that it is not only buckling over the entire length of the axial force pipe but also non-axisymmetric that is locally generated in the axial force pipe. 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 brace member, both ends of the stiffening pipe (outer pipe) are formed by thick steel pipes, or both ends of the axial force pipe (inner pipe) in order to protect both ends where the force is applied. What prevents local buckling by “end stiffening” in which a steel pipe material or a strip steel material is installed on the outer periphery is known (for example, see Patent Document 1).

Also, a weld bead is built up on the outer periphery of the joint member fixed at both ends of the axial force pipe (inner pipe), and the outer periphery of the weld bead is cut to allow a gap with the stiffening pipe (outer pipe). A technique for preventing local buckling by forming a “minimum gap” by reducing the size is known (for example, see Patent Document 2).
JP-A-6-346510 Japanese Patent No. 2711994

  However, in the method of preventing local buckling by “end stiffening” as described in Patent Document 1, for those in which only axial force is introduced into the axial force tube, compression plastic deformation in the axial force tube However, when a force in the bending direction is applied to the axial force tube, there is a problem that the compressive plastic deformation is not sufficiently promoted. Therefore, there is a case where the axial force pipe cannot be rigidly joined to the building structure because no force in the bending direction is applied to the axial force pipe (outer pipe). There is a problem that a device for reducing friction is necessary.

  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 is capable of preventing local buckling of an axial force tube even when a force in a bending direction is applied to the axial force tube. It is an object of the present invention to provide a double steel pipe type brace member that can be manufactured using a conventional technique without the need to set a small gap with the pipe.

The features of the present invention for solving such problems are as follows.
(1) An axial force tube that is installed in a building structure and receives an axial force, and a stiffening tube that is inserted through the axial force tube. The axial force tube is formed by the stiffening tube. A double steel pipe brace member that suppresses the occurrence of buckling when axial compressive stress is applied to the pipe, wherein an auxiliary stiffening pipe is inserted into the axial force pipe. Mold brace member.
(2) An axial force tube that is installed in a building structure and receives an axial force; and a stiffening tube that is inserted into the axial force tube. A double steel pipe-type brace member that suppresses the occurrence of buckling when axial compressive stress is applied, and has an auxiliary stiffening pipe that passes through the axial force pipe therein. Steel pipe type brace member.
(3) The range in which the auxiliary stiffening tube is inserted is only in the vicinity of both ends of the axial force tube, and is the axial length of the axial force tube. From the end of the axial force tube, the axial force tube The double steel pipe brace member according to (1) or (2), wherein the diameter is in a range of 0.5 to 3 times the diameter of the steel sheet.

  According to the present invention, since the pipe end of the axial force pipe of the double steel pipe brace member is stiffened from both sides by the inner and outer stiffening pipes, a force in the bending direction is applied to the axial force pipe. Even in such a case, the axial force tube can be stiffened, and the management width (allowable range) of the gap between the axial force tube and the stiffening tube can be made relatively wide.

  Therefore, the double steel pipe brace member can be pin-bonded to the structural member without being rigidly bonded or specially devised. At the same time, the amount of seismic energy absorbed by the axial force tube itself is increased, and the damping effect is also promoted.

  In addition, since the gap between the axial force tube and the stiffening tube required for manufacturing can be set wider than before, the operation of inserting the axial force tube into the stiffening tube is facilitated.

  In the present invention, an axial force tube that is installed in a building structure and receives axial force is stiffened by a stiffening tube, so that double buckling is suppressed when axial compressive stress is applied to the axial force tube. In the steel pipe type brace member, the axial force tube is stiffened from both the inner and outer surfaces, so that the axial force tube can be stiffened even when a force in the bending direction is applied to the axial force tube. That is, when the outside of the axial force tube is stiffened by a stiffening tube, the auxiliary stiffening tube is inserted inside the axial force tube, and the inside of the axial force tube is stiffened by the stiffening tube. In some cases, an auxiliary stiffening tube is installed outside the axial force tube.

  Since local buckling occurs mainly near the end of the axial force tube as described below, it is sufficient to stiffen only the vicinity of both ends of the axial force tube from both sides. The range in which the axial force tube is stiffened from the inner and outer surface sides is only in the vicinity of both ends of the axial force tube, is the axial length of the axial force tube, and the diameter of the axial force tube from the end of the axial force tube It is preferable to make it into the range of 0.5 times or more and 3 times or less.

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

  FIG. 1 is a partial cross-sectional side view schematically showing one end of a double steel pipe brace member according to an embodiment of the present invention (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. Moreover, in the following FIGS. 2-4, the same code | symbol is attached | subjected to the same part or an equivalent part, and some description is abbreviate | omitted.

  In FIG. 1, a double steel tube brace member 10 is fixed to 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 the cross gusset plate 4 fixed to the end plate 3.

  An auxiliary stiffening tube 5 having an outer diameter smaller than the inner diameter of the axial force tube 1 is inserted into the axial force tube 1 within a predetermined range from both ends toward the center in the length direction of the tube. The end of the auxiliary stiffening tube 5 is fixed to the end plate 3.

  The axial force pipe 1 is preferably a steel pipe made of a low yield point steel material, and the stiffening pipe 2 and the auxiliary stiffening pipe 5 are preferably steel pipes having a tensile strength of STK400 or higher. When compressive stress is applied to the axial force tube 1, the axial force tube 1 is constrained in the tube circumferential direction by the stiffening tube 2, and at the same time, the existence range of the auxiliary stiffening tube 5 in the end of the axial force tube 1. In FIG. 2, the auxiliary stiffening pipe 5 is restrained in the pipe circumferential direction to achieve end portion reinforcement. That is, the axial force tube 1 is less likely to be bent at both ends where local buckling is likely to occur. 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 act on the axial force tube 1, the axial force tube 1 has the existence range of the auxiliary stiffening tube 5 at its end, Since stiffening is performed in the tube axial direction and the circumferential direction, local buckling is less likely to occur in this range, and compression plastic deformation occurs in a wide range of the axial force tube 1 (over the entire length in the axial direction). The seismic energy can be absorbed sufficiently.

  In addition, when the double steel pipe brace member of the present invention is used, local buckling is unlikely to occur even when a double steel pipe brace member is manufactured by making the wall thickness of the axial force pipe smaller than the conventional one. The vibration performance can be demonstrated.

  In the present embodiment, the outer diameter and thickness of the auxiliary stiffening tube 5 are not limited. However, as described below, the auxiliary stiffening tube 5 is easily inserted into the axial force tube 1. It must be manufacturable and prevent local buckling.

  FIG. 6 is a frequency distribution diagram showing a length position where local buckling occurs in an axial force pipe in a conventional double steel pipe brace member (in the case where the auxiliary stiffening pipe 5 is not provided in FIG. 1). The vertical axis represents the frequency, and the horizontal axis represents the ratio of the buckling length to the steel pipe diameter (the length position where local buckling occurs measured from the pipe end). According to FIG. 6, local buckling does not occur when the buckling length is less than half the steel pipe diameter (steel pipe radius) and the buckling length is three times or more the steel pipe diameter. And, the local buckling in the length position (0.5 ≦ buckling length / steel pipe diameter <1.0) that is greater than the radius of the steel pipe and less than the diameter accounts for about 55% of the total, It can be seen that the local buckling of the position of length less than 1.5 times (0.5 ≦ buckling length / steel pipe diameter <1.5) accounts for about 87% of the total.

  Therefore, if the axial length of the auxiliary stiffening tube 5 is 0.5 to 1 times the outer diameter of the axial force tube 1, the occurrence of local buckling can be prevented to a considerable extent. More preferably, the outer diameter of the axial force tube 1 is 0.5 times or more and 1.5 times or less. In order to sufficiently prevent the occurrence of local buckling, the length of insertion of the auxiliary stiffening tube 5 into the axial force tube 1 is 0.5 mm of the outer diameter of the axial force tube 1 from the end of the axial force tube 1. It is preferable that the axial length be in the range of not less than twice and not more than 3 times.

  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 clearance between the axial force tube 1 and the auxiliary stiffening tube 5 is such that the operation of inserting the auxiliary stiffening tube 5 into the axial force tube 1 is possible. The force tube 1 can be made to such an extent that it can be plastically deformed in a wave shape (axisymmetric plastic deformation).

  Further, the surface of the auxiliary stiffening tube 5 may be subjected to an unbonding process in order to reduce friction between the inner peripheral surface of the axial force tube 1 and the outer peripheral surface of the stiffening tube 2.

  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. In addition, an “attachment plate” parallel to the end plate 3 is fixed to the end of the cross gusset plate 4, the attachment plate is fixed to the building structure, is brought into contact with the installation plate, and both are joined by bolts. May be.

  Furthermore, the joining means with the building structure of the double steel pipe brace member of the present invention is not particularly limited, and pin joining may be performed.

  Further, a stopper (not shown) can be provided on the end plate 3 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 as shown below.

Below, an example of the manufacturing method of the double steel pipe type brace member 10 is demonstrated. The procedure of inserting the auxiliary stiffening tube 5 into the axial force tube 1 includes (a) a step of welding the auxiliary stiffening tube 5 to the end plate 3, and (b) the axial force tube 1, the end plate and the stiffening tube 2. The process of welding. More specifically, the following steps (a) to (d) are performed.
(A) Fillet weld the auxiliary stiffening tube 5 to the end plate 3.
(B) The auxiliary stiffening tube 5 with the end plate 3 is inserted into both ends of the axial force tube 1. Thereafter, the axial force tube 1 is inserted into the stiffening tube 2.
(C) Then, the axial force tube 1 is completely penetration welded to the end plate 3 using a semi-automatic carbon dioxide arc welding or the like.
(D) Finally, the stiffening tube 2 and the axial force tube 1 are plug welded at the center of the material. The stiffening tube 2 may be welded to the end plate at one end.

  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 (Embodiment 2).

  In FIG. 2, a double steel pipe brace member 20 includes an axial force tube 1 that receives an axial force, and an axial force tube 1 in which a stiffening tube 2 is accommodated and is pin-bonded to an end plate 3. The clevis 7 is formed integrally.

  The clevis 7 is joined to a clevis joint (not shown) installed in the building structure so as to be tiltable. At this time, a joining pin is inserted into the through hole 71 provided in the clevis 7.

  The auxiliary stiffening tube 5 is disposed on the outer peripheral surface 21 side of the axial force tube 1 in a predetermined range from the end plate 3 toward the center in the length direction of the tube. At this time, the axial force tube 1 is restrained from deformation in the tube axis direction and the circumferential direction.

  Therefore, the double steel pipe brace member 20 is obtained by reversing the inside and outside of the positional relationship between the stiffening pipe 2 and the auxiliary stiffening pipe 5 with respect to the axial force pipe 1 in the double steel pipe type brace member 10 shown in the first embodiment. Yes, exhibiting the same vibration control performance.

  Also in the second embodiment, the outer diameter and thickness of the auxiliary stiffening tube 5 are not limited.

  The range in which the auxiliary stiffening tube 5 is inserted is the same as in the first embodiment.

  A test for confirming the performance of the double steel pipe brace member shown in FIG. 1 as 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, the double steel pipe brace member 30 (hereinafter referred to as “test body 30”) subjected to the test has an axial force tube 1 having an outer diameter of 114.3 mm, a thickness of 7.5 mm, a length of 2406 mm, and 100 N. / Mm ² grade low-yield point steel pipe for building structure (manufactured by JFE Steel Co., Ltd., trade name “RIVEFLEX100-S”, RF100-S), stiffening pipe 2 has an outer diameter of 139.8 mm and a thickness of 6. The steel pipe of 6 mm, length 2450 mm, STK400, and end plate 3 were round steel plates having a thickness of 22 mm, an outer diameter of 124.6 mm, and SM490A.

  In addition, the cross gusset plate 4 is a 22 mm thick, 370 × 166 mm rectangular plate, one SM490A (4a), and a 19 mm thick, 370 × 72 mm rectangular plate, two SM490A (4b). Is. The cross gusset plate 4 has a hole for a high-strength bolt to be attached to the testing machine.

  Further, inside the axial force tube 1, an auxiliary stiffening tube 5 which is a steel tube having an outer diameter of 90.0 mm, a thickness of 4.5 mm and STK 400 is inserted in a range of 300 mm in the tube axis direction. At this time, the auxiliary stiffening tube 5 is fillet welded to the end plate 3. The leg length is 4 mm.

  In the test body 30, the auxiliary stiffening tube 5 is fillet welded to the end plate 3, the auxiliary stiffening tube 5 with the end plate 3 is inserted into both ends of the axial force tube 1, and then the axial force is applied to the stiffening tube 2. The tube 1 was inserted, the axial force tube 1 was completely welded to the end plate 3 by semi-automatic carbon dioxide arc welding, and the stiffening tube 2 and the axial force tube 1 were plug welded at the center of the material.

  Further, in order to compare the test results, a double steel pipe brace member of a comparative test body 31 (not shown) which is the same as the test body 30 except that the auxiliary stiffening pipe 5 is not inserted was also manufactured.

  The grips 41 respectively fixed to both ends of the test body 30 were coupled to a force applying device, and a test was performed in which an axial compressive force was applied to the axial force tube 1 by the force applying device. The comparative test body 31 was similarly tested.

  A test for confirming the performance of the double steel pipe brace member according to Embodiment 1 of the present invention was performed using the test apparatus shown in FIG. 4 as the force applying apparatus. In FIG. 4, the testing machine 8 includes a fixed-side force application jig 81 (hereinafter referred to as a force-receiving jig 81), a force application column 83 that tilts around a tilting fulcrum 82, and a force application. A tilting-side force applying jig 84 (hereinafter, referred to as an “applying jig 84”) fixed to the column for use 83 and a tilt drive means (not shown) for tilting the force post 83 are provided. .

  The attachment plates 42 fixed to both ends of the axial force tube 1 of the test body 30 are rigidly coupled to the force receiving jig 81 and the force applying jig 84 by bolts, respectively. Therefore, since the force applying column 83 repeatedly tilts in the plane (repetitively falls and stands within a predetermined range), a bending force acts on the axial force tube 1 in addition to the axial tensile force and compressive force. It will be.

  FIG. 5A shows a stress strain diagram which is a measurement result when a force is applied to the test body 30 using the test apparatus shown in FIG. In FIG. 4, first, the force applying column 83 is tilted to the left (in the direction of the black arrow in FIG. 4), and a compressive force is applied to the test body 30 (axial force tube 1). According to FIG. 5 (a), after starting the elastic deformation from the origin and compressing and yielding, the plastic deformation is progressing while being slightly hardened. Thereafter, when the force application column 83 reached position D in FIG. 4, the force application column 83 was returned toward position C. Further, by tilting the force applying column 83 to the right (in the direction of the white arrow in FIG. 4) and applying a tensile force to the test body 30 (axial force tube 1), the test body 30 is moved to FIG. As shown, tensile yielding occurred, and plastic deformation progressed while being slightly hardened. Eventually, when the force column 83 reached position E in FIG. 4, the force column 83 was returned toward position C.

  Thereafter, the tilting of the force applying column 83 was repeated in the same manner, and a hysteresis curve having a Bauschinger effect was drawn on the stress strain diagram of the test body 30 (axial force tube 1) as shown in FIG. When the force was applied for the 10th time, the performance as a brace was lost due to a rapid increase in stress at the position “I”.

  On the other hand, FIG. 5B shows the results when the test similar to the test body 30 was performed on the comparative test body 31. That is, also in the comparative test body 31, the hysteresis curve which has a Bauschinger effect according to Fig.5 (a) was drawn. The hysteresis curve shows the same behavior as that of the test body 30.

  However, at the time of the seventh applied force, the performance as a brace is lost at the position “A” due to a rapid increase in stress.

  From the above test results, by inserting the auxiliary stiffening tube 5, the number of times that the axial force tube 1 can be repeatedly applied is increased 1.5 times from 6 times to 9 times (in terms of energy absorption amount, it is increased 1.6 times) Therefore, it was shown that the double steel pipe brace member of the present invention has a remarkable effect when a force in the bending direction is applied to the axial force pipe.

The side view of the partial cross section which shows a double steel pipe type brace member (an auxiliary stiffening pipe is an inner pipe of an axial force pipe) typically (embodiment 1). The side view of the partial cross section which shows a double steel pipe type brace member (an auxiliary stiffening pipe is an outer pipe of an axial force pipe) typically (embodiment 2). The side view of the partial cross section of the test body for confirming the performance of the double steel pipe type brace member of this invention. The external view explaining the testing apparatus and test method of the performance confirmation test of a double steel pipe type brace member. (A) Stress-strain diagram of a specimen (invention example). (B) Stress-strain diagram of a comparative specimen (comparative example). The frequency distribution diagram which shows the length position where the local buckling generate | occur | produces in the conventional double steel pipe type brace member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axial force pipe 2 Stiffening pipe 3 End plate 4 (4a, 4b) Cross gusset plate 5 Auxiliary stiffening pipe 7 Clevis 8 Test machine 10 Double steel pipe type brace member (Embodiment 1)
20 Double steel pipe brace member (Embodiment 2)
21 Axial force pipe outer peripheral surface 30 Double steel pipe brace member (test body)
31 Double steel pipe brace member (Comparative specimen)
41 Through-hole 42 Mounting plate 71 Through-hole 81 Fixing jig on the fixed side (power receiving jig)
82 Tilt fulcrum 83 Force column 84 Tilt side force jig (forced jig)

Claims (3)

An axial force tube that is installed in a building structure and receives an axial force, and a stiffening tube that is inserted through the axial force tube. The stiffening tube axially compresses the axial force tube. A double steel pipe brace member that suppresses the occurrence of buckling when stress is applied,
An auxiliary stiffening pipe is inserted into the axial force pipe. An axial force pipe installed in a building structure and receiving axial force; and a stiffening pipe inserted into the axial force pipe; and the axial compressive stress is applied to the axial force pipe by the stiffening pipe. A double steel pipe brace member that suppresses the occurrence of buckling when
A double steel pipe-type brace member having an auxiliary stiffening pipe through which the axial force pipe is inserted. The range through which the auxiliary stiffening tube is inserted is only in the vicinity of both ends of the axial force tube, and is the axial length of the axial force tube, and the diameter of the axial force tube from the end of the axial force tube. The double steel pipe brace member according to claim 1 or 2, wherein the range is 0.5 times or more and 3 times or less.

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