JP3382178B2 - Brace with anti-buckling steel tube - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brace having an anti-buckling steel pipe.

[0002]

2. Description of the Related Art An unbonded steel frame brace as a seismic element for a beam-column structure of a steel frame building or a steel frame reinforced concrete structure is known, for example, from Japanese Patent Application Laid-Open No. 7-324377. On the outer periphery of the brace material of the unbonded steel brace, a steel pipe having a diameter that is substantially circumscribed is covered as a buckling stiffening material, and the steel pipe is fixed to the brace material at at least one position. When an excessive compression force acts on the brace material, the brace material is restrained from bending at the contact point between the brace material and the steel pipe by the restraining force of the steel pipe, and buckling is prevented.

In the case of this unbonded steel brace,
Since the steel pipe has a diameter that almost circumscribes the brace material, if the brace material or the steel pipe is slightly deformed (has an initial deflection), it is impossible to cover the brace material with the steel pipe. Therefore, it is necessary to manufacture the brace material and the steel pipe with high accuracy, and it is necessary to take care so that the brace material and the steel pipe are not deformed during transportation and handling. Furthermore, if the brace material is already deformed when reinforcing the existing brace with a steel pipe, it is necessary to correct the deformation of the brace material before covering the steel pipe, which is a very troublesome and difficult task. .

On the other hand, there is an unbonded brace constructed so that when the gap between the brace material and the steel pipe is large, concrete is filled to suppress buckling. However, in order to cut off adhesion with concrete, it is necessary to apply an insulating material to the surface of the brace and to fill the gap with concrete to prevent leakage of concrete, which is troublesome to manufacture.

[0005]

In view of such drawbacks of the prior art, an object of the present invention is to brace a reinforced steel pipe even if the brace material or the steel pipe is slightly deformed or the gap between them is large. It is to provide a brace that can be easily attached to a piece of material.

Another object of the present invention is to prevent the buckling of the brace member by uniformly supporting and reinforcing it by the steel pipe over its entire length when it is subjected to an axial compressive load.
It is to provide braces.

[0007]

In order to solve this problem, a brace according to the present invention comprises a steel brace material,
A steel pipe that surrounds the brace material and a large number of bolts that are screwed into the steel pipe from the outside in the radial direction are provided, and a gap between the brace material and the steel pipe is formed over the entire circumference of the brace material. The size is selected, and the brace material is supported by bolts distributed around the brace material.

In this case, it is desirable that the bolts are arranged at a constant interval in the axial direction of the steel pipe so that the brace material is uniformly supported by the steel pipe in the axial direction. Further, in order to reduce friction between the bolt and the brace material, it is desirable that the tip of the bolt on the radially inner side is rounded. Furthermore, the bolt is held on the steel pipe by the double nut, and after screwing the bolt,
When the lock nut of the double nut is fixed to the steel pipe, the bolt is prevented from loosening, and the bolt is securely held by the steel pipe.

[0009]

In the case of the brace according to the present invention, the steel pipe surrounds the brace material at intervals in the radial direction, and a large number of bolts distributed around the brace material support the brace material. A gap is formed between the brace material and the steel pipe over the circumference.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example in which a brace 1 according to the present invention is applied to a column-beam frame structure 2 of a building shown by a chain double-dashed line. 2 is a transverse sectional view taken along line II-II of this brace 1, FIG. 3 is a longitudinal sectional view taken along line III-III of FIG. 2, and FIG. 4 is a brace shown in FIG. FIG.

The brace 1 according to the present invention comprises a brace material 3 made of steel and a steel pipe 4 surrounding the brace material 3 at a distance from the outside in the radial direction (see FIG. 2). The brace material 3 is made of H-section steel reinforced by channel steel in the drawing, but may be made of channel steels having various cross-sectional shapes or shaped steels such as angle steels or a combination thereof. Although the steel pipe 4 is a square pipe in the figure,
Other polygonal tubes or circular tubes may be used. When newly installing a brace, this steel pipe 4 is a pipe having a closed cross section from the beginning as shown in the figure, but when installing it on an existing brace, it is divided into two parts, and welding or bolts are performed on site. By joining, a tube having a closed cross section is formed and attached so as to surround the brace material 3. Both ends of the brace member 3 are directly joined to the column-beam frame 2, or are fixed to the column-beam frame 2 by, for example, fixing reinforcing bars.

A large number of bolts 5 are screwed into the steel pipe 4 from the outside in the radial direction. As shown in an enlarged view in FIG. 4, the bolt 5 is screwed into the steel pipe 4 so that its tip on the radially inner side has a small gap c with or comes into contact with the brace material 3, and is retained by the double nut 6. There is. After screwing in, lock nut 6 of double nut 6
When a is tightened and fixed to the steel pipe 4 by welding (dotted welding point 6
The bolt 5 is prevented from loosening. The radially inner tip of the bolt is rounded. As a result, when the brace member 3 receives a tensile force or a compressive force and expands or contracts in the event of an earthquake or the like, the friction between the brace and the tip of the bolt is reduced, and a so-called unbonding action is satisfactorily exhibited.

A large number of bolts 5 are arranged in the circumferential direction and the axial direction of the steel pipe 4 so as to be distributed. The bolts 5 are preferably arranged at regular intervals (pitch) in the axial direction. Further, the steel pipe 4 can be fixed to the brace member 3 at at least one position. This fastening is performed, for example, by a rod that laterally penetrates the steel pipe 4 and the brace member 3.

When the brace 1 having the above structure is newly installed, the brace material 3 and the steel pipe 4 can be separately transported to the site. Then, the brace material 3 is inserted into the steel pipe 4 at the site and assembled, and both ends of the brace material 3 are attached to the column beam structure 2.

When the steel pipe 4 is attached to the existing brace material 3, the steel pipe 4 divided into two is covered on the brace material 3 and welded or bolted to form the closed steel pipe 4.

Next, all the bolts 5 are tightened to such an extent that the tips of the bolts 5 touch or do not touch the brace material 3, and the lock nut 6a of the double nut 6 is spot-welded to the steel pipe 4 so that the bolt 5 is fixed. Fix it. Thereby, the brace material 3 is uniformly supported on the steel pipe 4 through the bolt 5 over the entire length and the entire circumference.

In the case of the brace according to the present invention, even if the brace material 3 is deformed, the steel pipe 4 is attached to the brace material 3
Can be attached to. This is because the steel pipe does not circumscribe the brace material but surrounds the brace material at intervals in the radial direction. Further, since the steel pipe receives the force transmitted from the brace member via the bolt, the steel pipe reinforces the brace member and buckling of the brace member is prevented. The bolt can be screwed so that the radially inner tip of the bolt has a small gap or even contacts the deformed brace material, so that the deformed brace material is uniformly supported and reinforced over its entire length. And stress concentration does not occur.

In the above embodiment, the pitch of the bolt 5 and the strength of the steel pipe 4 can be determined according to the application.

When the bolt pitch is increased, the brace material buckles between them. However, if the gap between the brace material and the buckling stiffening material (steel pipe) is appropriately set, the steel pipe wall will be warped due to buckling. Since it suppresses, seismic energy can be absorbed without lowering the yield strength, and excellent seismic performance is exhibited. In this case, the number of bolts can be reduced, the manufacturing work can be reduced, and the economical efficiency can be improved.

[0021]

In the brace according to the present invention, the sizes of the steel pipe and the brace material are selected so that a gap is formed between the brace material and the steel pipe over the entire circumference of the brace material, and the brace material is provided around the brace material. Since it is supported by the dispersed bolts, even if the brace material or the steel pipe is slightly deformed, the steel pipe can be covered with the brace material. Furthermore, since the steel pipe receives the force transmitted from the brace member via the bolt, the brace member is reinforced by the steel pipe and buckling of the brace member can be prevented. Since the bolt can be screwed so that the tip of the inner side in the radial direction of the bolt has a small clearance or comes into contact with the deformed brace material, the deformed brace material is evenly supported over its entire length and entire circumference. It can be reinforced and stress concentration does not occur.

[Brief description of drawings]

FIG. 1 shows an example in which a brace according to the present invention is applied to a column beam structure of a building.

2 is a cross-sectional view of the brace shown in FIG. 1 taken along line II-II.

3 is a vertical cross-sectional view of the brace of FIG. 2 taken along line III-III.

4 is a partially enlarged view of the brace of FIG.

[Explanation of symbols]

1 brace Two-column structure 3 braces 4 steel pipe 5 Volts 6 double nuts 6a Lock nut c gap

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Haruo Yokoyama 1-1-8 Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Co., Inc. Construction Department (72) Inventor Ueyama 2-1-4 Uchiyuki-cho, Chiyoda-ku, Tokyo Toden Design Co., Ltd. Company Building Headquarters (72) Inventor Takayuki Aoyagi 2-1-4 Uchisaiwaicho, Chiyoda-ku, Tokyo Toden Design Co., Ltd. Building Headquarters (72) Inventor Hiroshi Kaneko 1-5-1 Otsuka, Inzai City, Chiba Takenaka Corporation Technical Research Institute (72) Inventor Michikazu Kobayashi 1-5-1 Otsuka, Inzai City, Chiba Takenaka Corporation Technical Research Laboratory (56) Reference JP-A-11-29987 (JP, A) JP-A-10- 231555 (JP, A) JP-A-9-328813 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) E04B 1/58

Claims (4)

(57) [Claims] 1. A bracing material made of steel, a steel pipe surrounding the brace material, and a large number of bolts screwed into the steel pipe from the outside in the radial direction, and a gap between the brace material and the steel pipe over the entire circumference of the brace material. Brace material, in which the sizes of the steel pipe and the brace material are selected so that the brace material is formed, and the brace material is supported by bolts distributed around the steel tube. 2. The brace according to claim 1, wherein the bolts are arranged at regular intervals in the axial direction of the steel pipe. 3. The brace according to claim 1, wherein the tip of the bolt on the radially inner side is rounded. 4. The bolt is held on the steel pipe by a double nut, and after the bolt is screwed in, the lock nut of the double nut is fixed to the steel pipe. Braces.