JPH10169089A - Steel beam - Google Patents

Abstract

(57) [Problem] To provide a steel beam capable of preventing breakage of the beam and contributing to the improvement of the seismic resistance of a structure by efficiently absorbing energy due to external force caused by an earthquake, a strong wind, or the like. The task is to SOLUTION: A beam 3 made of an H-shaped steel material constituting a frame 1
A deformation restraining member 5 for restraining deformation of the beam 3 is disposed between the upper and lower flanges 3a, 3a at the ends of the beam 3, and the upper and lower restraining surfaces 5b, 5b are connected to the flange 3a at the end of the beam 3. , And is formed by a curved surface A that gradually separates toward the center thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel beam suitable for use as a beam constituting a frame of various structures such as a building.

[0002]

2. Description of the Related Art As is well known, in the frame of various structures such as a skyscraper, when a steel beam is used as a beam, if an excessive external force due to an earthquake or a strong wind acts on the steel beam, the energy due to the external force is generated. Concentrates on the beam end, which is the joint with the column,
The end of the beam reaches the yield point and plasticizes. Then, the plasticized region gradually expands from the beam end to the beam center. At this time, when the deformation due to the plasticization of the beam progresses, the steel beam may be broken at the joint portion of the beam with the column at the end thereof. In order to avoid the occurrence of such a phenomenon, a technique of increasing the strength of the steel beam is basically adopted.

[0003]

However, the above-described conventional techniques have the following problems. In other words, in order to increase the strength of the steel beam, the cross-sectional area of the steel beam increases, which not only reduces the indoor space, but also increases the cost of materials, increases the cost of the entire frame due to the increase in the weight of members, etc. Problem. In addition, since energy due to external forces due to earthquakes, strong winds, etc. is concentrated at the ends of the beam, if the strength of the entire steel beam is increased based on this portion, the central portion of the beam will have more strength than necessary. Will be. The present invention has been made in consideration of the above points, by efficiently absorbing energy due to external force caused by an earthquake or strong wind, etc.
An object of the present invention is to provide a steel beam that can prevent a beam from breaking or the like and contribute to improving the earthquake resistance of a structure.

[0004]

According to the present invention, a beam constituting a skeleton of a structure is a steel beam made of an H-shaped steel material having flanges on upper and lower sides thereof, and is joined to a column constituting the skeleton. At the end of the steel beam, a deformation restraining member for restraining deformation of the steel beam is disposed between upper and lower flanges, and the upper and lower surfaces of the deformation restraining member are formed of the steel beam. An end portion is formed of a curved surface that abuts on the flange and gradually separates toward the center of the steel beam.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a steel beam beam according to the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 1 denotes a frame of a structure such as a building, 2 denotes a column made of, for example, steel pipe, and 3 denotes a beam (steel beam) made of H-shaped steel.

In this figure, a deformation restricting member 5 for restricting the deformation of the beam 3 is provided at a portion where the column 2 and the beam 3 constituting the frame 1 are joined.

The deformation restricting member 5 is provided in a space surrounded by upper and lower flanges 3a, 3a of the beam 3 and the web 3b. This deformation restricting member 5 is made of, for example, concrete, and one surface thereof is a fixed surface 5a which abuts against the side surface of the column 2, and two surfaces on both sides thereof are flanges 3a, 3
a are constrained surfaces 5b, 5b opposed to a. Each restraining surface 5b is formed by a curved surface A that abuts on the flange 3a on the fixed surface 5a side, that is, on the end side of the beam 3, and gradually separates from the flange 3a toward the center of the beam 3.

The curvature of the curved surface A forming each of the constraint surfaces 5b is set based on, for example, the curvature of the flange 3a of the beam 3 when yield strain occurs in the beam 3. More specifically, the curvature φ of the flange 3a when the yield strain occurs in the beam 3 in the frame 1 is generally given by: φ = (| ε _c | + | Ε _t |) / H (where ε _c is the bending compressive strain of beam 3 and ε _t is the bending tensile strain)
It is represented by The yield point of the beam 3 is the end on the column 2 side. Therefore, the curvature φf of the flange 3a of the beam 3 at the yield point when the maximum moment is generated in this portion is given by: φf = (| _c ε _y | _{+ | t ε y |) /} H ( provided that, _c epsilon _y flexural compressive strain at yield, is _t epsilon _y represented by flexural tensile strain) at yield. That is, the curvature φf ′ of the curved surface A forming the restraint surface 5b is set to coincide, for example, with the curvature φf at the yield point when the maximum moment occurs in the beam 3 (φf ′ = φf).

Such deformation restraining members 5 are respectively disposed on beams 3, 3 located on both sides of the column 2, and these deformation restraining members 5, 5 provided on the column 2 are provided.
Is fastened to the column 2 by a steel rod 7 to which a prestress is applied and a nut 8 screwed to the steel rod 7.

As described above, the curvature of the restraint surface 5b of the deformation restraint member 5 is adjusted by changing the curvature of the flange 3 when the yield strain occurs in the beam 3.
When the curvature is matched with the curvature φf of a, the beam 3 exhibits the following behavior due to an external force such as an earthquake or wind force. When an external force caused by an earthquake, wind, or the like is excessively applied, first, at the end on the column 2 side of the flange 3a of the beam 3 where the maximum moment occurs, the strain in a minute cross section of this end changes the curvature φf. When it reaches, the minute cross section of the flange 3a comes into contact with the restraint surface 5b of the deformation restraint member 5, and its deformation is forcibly restrained. Then, the contact point between the flange 3a of the beam 3 and the restraining surface 5b of the deformation restraining member 5 shifts toward the center of the beam 3 in the length direction. Accordingly, the position where the maximum moment occurs is shifted to another minute section adjacent to the minute section, and the flange 3a of the beam 3 in that part also comes into contact with the constraint surface 5b of the deformation constraint member 5. Therefore, the deformation is forcibly restrained.

In this way, at the stage where the beam 3 reaches the yield point from the end and is plasticized, further deformation is restrained by the deformation restraining member 5, and the position reaching the yield point is closer to the center of the beam 3. , And the plasticized region is expanded.

In the above-mentioned beam 3, the beam 3 made of H-shaped steel is used.
A deformation restricting member 5 for restricting deformation of the beam 3 is disposed between upper and lower flanges 3a, 3a at the ends of the upper and lower flanges 3a.
At the end of the beam 3, b and 5b are formed with curved surfaces A which abut against the flange 3a and gradually separate toward the center. Thereby, when a strong external force acts due to an earthquake or wind, when the beam 3 reaches the yield point and is plasticized, further deformation can be restrained by the deformation restraining member 5, and the position where the beam 3 is plasticized can be changed. Can be sequentially shifted toward the center of the image. In this way, the plasticizing region of the beam 3 is expanded toward the center of the beam 3 and further deformation at the end of the beam 3 is restrained by the deformation restricting member 5, so that the beam 3 is fixed at the end of the beam 3. The above energy is not concentrated, the beam 3 is prevented from breaking from the end, and the energy can be dispersed to the center of the beam 3.
Energy can be efficiently absorbed as a whole without waste. Therefore, such a beam 3 can absorb much higher energy than a simple beam without the deformation restraining member 5, and the seismic resistance of the skeleton 1 can be greatly improved. Moreover, the deformation restraining member 5
Is arranged between the upper and lower flanges 3a, 3a of the beam 3, so that it is not necessary to increase the cross-sectional area of the beam 3, thereby reducing the indoor space or increasing the cost due to a significant increase in the weight of members. It is possible to obtain high economic benefits without causing such problems.

In the above-described embodiment, the steel beam according to the present invention may be applied to the entire skeleton 1, or may be applied to a skeleton, such as a specific layer whose deformation is predicted when a strong earthquake or the like occurs. You may apply to only one part. Further, the deformation restricting member 5 is not limited to the one made of concrete. If it has a predetermined proof stress and rigidity, for example, the whole may be formed only with metal, or only the surface may be coated with metal. May be. Further, the constraint surface 5 of the deformation constraint member 5
The curvature of the curved surface A forming b is not limited to the curvature φf at the time of the occurrence of the yield strain of the beam 3 described above. For example, the curvature is set to a value smaller than the curvature φf before the beam 3 reaches the yield point (the elastic range). (Within the range), the deformation may be set to be restrained, or within a range that does not cause breakage from the end of the beam 3, the beam 3 may be set within the plastic region beyond the yield point.
May be restricted so that the plastic deformation does not exceed a certain value. In addition, other than the above, each configuration in the above-described embodiment, for example, a method of fixing the deformation restricting member 5 and the like may be any configuration without departing from the gist of the present invention.

[0014]

As described above, according to the steel beam of the present invention, a deformation restraining member is arranged between the upper and lower flanges at the ends of the steel beam made of H-shaped steel. The upper and lower surfaces are formed as curved surfaces that abut against the flange at the end of the beam and gradually separate toward the center. In this way, when a strong external force is applied due to an earthquake or wind, the deformation of the steel beam from the end to the yield point can be restrained by the deformation restraining member, and energy is concentrated at the end of the steel beam. Instead, the steel beams are dispersed at the center portion side, so that the steel beams can be prevented from breaking from the ends. Therefore, it is possible to absorb much higher energy than a simple beam without a deformation constraint member, and it is possible to greatly improve the earthquake resistance of a structure including such a steel beam. In addition, since the deformation restraining member is configured to be housed between the upper and lower flanges of the beam, there is no need to increase the cross-sectional area of the beam, thereby reducing the indoor space or increasing the cost due to a significant increase in the weight of the member. It is possible to obtain high economic benefits without causing such problems.

[Brief description of the drawings]

FIG. 1 is an elevational sectional view showing a part of a frame of a structure to which a steel beam according to the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 2 Column 3 Beam (steel beam) 5 Deformation restraint member A Curved surface

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomomi Kanemitsu 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Tetsuya Hanzawa 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation Inside the corporation

Claims (1)

[Claims] 1. A beam constituting a skeleton of a structure is a steel beam made of an H-shaped steel material having a flange on upper and lower sides thereof, and an end of the steel beam to be joined to a column constituting the skeleton is provided at an end of the beam. ,
A deformation restraining member for restraining deformation of the steel beam is provided between the upper and lower flanges, and the upper and lower surfaces of the deformation restraining member abut against the flange at the ends of the steel beam. A steel beam characterized by being formed with a curved surface gradually separated toward a central portion of the steel beam.