JP2012052374A - Beam end vibration control structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a beam end vibration control structure which has less restrictions on installing a vibration damper at a column-beam joint section and enables the vibration damper to effectively operate to exert a sufficient vibration control effect.SOLUTION: In a beam end vibration control structure, after a beam 1 is pin-connected to a column 5 so as to make the beam 1 vertically rotatable relative to the column 5, a steel member damper performing as a vibration damper 10 is interposed between a lower flange 3 of the beam and a lower diaphragm 7. The vibration damper comprises: a fixing section 10a to be fixed to the lower flange by fastening; an arm section 10b where one end section thereof is pin-connected to the lower flange so as to be horizontally rotatable relative to the lower flange and the other end section is outwardly extended in a width direction of the beam to be pin-connected to the lower diaphragm so as to be horizontally rotatable relative to the lower diaphragm; and a damper section 10c which is placed between the fixing section and the one end section of the arm section and elastically deforms due to a horizontal rotation of the arm section.

Description

  The present invention relates to a vibration damping structure for a structure such as a building, and more particularly to a beam end damping structure in which a damping damper is installed at a joint between a column and a beam.

As is well known, the vibration control structure for structures such as buildings adds vibration dampers to the key points of the structural framework composed of columns and beams, thereby reducing vibration energy from earthquakes to the vibration dampers. It is a seismic technology that minimizes structural frame damage by concentrating and absorbing.
This type of vibration control structure employs various types of vibration dampers, such as oil dampers, viscoelastic dampers, friction dampers, etc., among which steel dampers that utilize the plastic deformation of steel materials are in the form of walls and braces. It is said that it is preferable to install.

However, when the damping damper is installed in the form of a wall or brace with respect to the structural frame, it is inevitable to be restricted in plan and design, and in many cases, it cannot be optimally arranged at the optimum position.
For this reason, it is considered to install a damping damper for the beam end portion with relatively few such restrictions, and for example, a beam end damping structure as shown in Patent Document 1 and Patent Document 2 is also proposed. .

JP 2003-261993 A JP 2002-371626 A

The structure shown in Patent Document 1 is to install an axial force resistance joining element functioning as a vibration damper at the column beam joint in the form of a cane, but the form of the cane is more constrained than the form of a wall or brace. However, it is premised that the installation space for the column beam joint can be secured after securing the desired effective ceiling height under the beam, and interference with the equipment installed around it. In this respect, it is not always effective and is not widely applicable.
In addition, since sufficient buckling restraint is necessary to effectively operate the vibration damper in the form of a cane, the structure of the vibration damper and the connection structure to the columns and beams are complicated, and the cost is not high. Can't help

  In the structure shown in Patent Document 2, a plate-shaped preceding yield member as an axial force resistance element is provided in parallel with the lower flange of the beam to function as a vibration damper, which is also effective as a vibration damper. In order to function, sufficient buckling restraint by a stiffening material such as a grooved steel or a T-shaped steel is necessary, and the configuration is complicated and expensive as shown in Patent Document 1.

  In addition, in any case, since this type of damping damper needs to be replaced after it is activated during an earthquake, it is common to fasten bolts so that they can be replaced with columns and beams assuming future replacement. However, when the column beam has an open cross section such as an H-shaped steel, it can be bolted without any problem, but when the column has a closed cross section such as a square steel pipe, the bolt is simply tightened. However, it is necessary to use a special one-side bolt or a connection using a tap and a bolt, which is not preferable in terms of cost and workability.

  In view of the above circumstances, the present invention has few restrictions on installing a vibration damper for the beam-column joint, and can effectively operate the vibration damper to obtain a sufficient vibration damping effect. The object is to provide an appropriate beam end damping structure.

  The invention according to claim 1 is a beam end damping structure in which a damping damper made of a steel material is installed at a joint portion between a column and a beam of a structure, wherein the beam is made of H-shaped steel, The column is provided with a shear plate at a position facing the web of the beam, and a lower diaphragm is provided at a position facing the lower flange of the beam, and the tip of the lower flange is placed inside a notch recess provided in the lower diaphragm. The upper part of the web of the beam is pin-joined so as to be relatively rotatable in the vertical direction with respect to the upper part of the shear plate, and the damping damper is provided between the lower flange of the beam and the lower diaphragm. The damping damper includes a fixed portion that is fastened and fixed to the lower flange, and one end portion that is pin-joined so as to be horizontally rotatable with respect to the lower flange, and the other end portion that is Beam width An arm portion that extends outward and is pin-joined so as to be horizontally rotatable with respect to the lower diaphragm, and is provided between the fixed portion and one end portion of the arm portion, and is plastically deformed by horizontal rotation of the arm portion. It consists of a damper part.

  The invention according to claim 2 is the beam end damping structure according to claim 1, wherein an upper diaphragm is provided on the column at a position facing the upper flange of the beam, and the upper part of the web of the beam is provided. Instead of being pin-bonded to the upper portion of the shear plate, the top end portion of the upper flange of the beam is pin-bonded so as to be rotatable relative to the upper diaphragm in the vertical direction.

  The invention according to claim 3 is the beam end damping structure according to claim 1 or 2, wherein the fixed portion, the damper portion, and the arm portion of the damping damper are all made of a steel material of the same material. The damper portion is formed with a smaller cross section than the fixed portion and the arm portion.

  The invention according to claim 4 is the beam end damping structure according to claim 1, 2, or 3, wherein the damping damper is symmetrically arranged on both sides of the web on the lower surface side of the lower flange of the beam. It is characterized by.

  According to the beam end damping structure of the present invention, an excellent damping effect can be obtained by allowing the vibration energy to be absorbed by the damping damper after allowing the rotational motion at the column-beam joint, as well as a simple L Since the vibration damping damper with a flat shape is interposed between the lower flange of the beam and the lower diaphragm provided on the column, it is not necessary to secure a special space for installing the vibration damping damper. As in the case of the beam end damping structure, it is less subject to restrictions in plan and design, and it is possible to avoid interference with equipment installed around columns and beams.

In addition, since the vibration damper in the present invention is plastically deformed mainly by the in-plane shearing force and bending moment, buckling out of the plane does not easily occur. Therefore, various conventional vibration dampers Thus, no special stiffening element is required for buckling restraint, and sufficient simplification and miniaturization can be realized, which is advantageous in terms of cost.
In addition, it can be installed easily by simply fastening the bolts with the fixed part and arm part in close contact with the lower flange of the beam and the lower diaphragm of the column. It is possible to carry out without trouble.
Of course, the damping damper of the present invention can be designed freely and widely for the rigidity, proof stress, and fatigue life of the damper by setting the material, shape and dimensions of the damper part. Is widely applicable.

It is a figure which shows embodiment of the beam end damping structure of this invention. It is a figure which shows a damping damper same as the above. It is a figure which shows other embodiment same as the above. It is a figure which shows a FEM analysis model same as the above. It is a figure which shows the characteristic of the damper steel material which is an analysis model. It is a figure which shows an analysis result (load-deformation relationship) similarly. It is a figure which shows an analysis result (buckling deformation figure) similarly. It is a figure which shows the outline | summary of a structural experiment. It is a figure which shows the force program in a structural experiment equally. It is a figure which shows a structure experiment result (M-theta relation) similarly.

1 to 2 show an embodiment of a beam end damping structure of the present invention.
This is because the beam 1 is made of an H-shaped steel made up of a web 2, a lower flange 3 and an upper flange 4, and the column 5 is made of a square steel pipe, and the column 5 is located at a position facing the web 2 of the beam 1. A shear plate 6 is provided, and a lower diaphragm 7 and an upper diaphragm 8 are provided at positions facing the lower flange 3 and the upper flange 4 of the beam 1, respectively.
The lower diaphragm 7 is provided with a notch recess 7a as shown in FIGS. 1 (c) and 1 (d), and the beam 1 is changed to the column 5 with the tip of the lower flange 3 of the beam 1 disposed inside thereof. On the other hand, it joins with the following structures.

That is, in this embodiment, only the upper part of the web 2 of the beam 1 is bolted to the upper part of the shear plate 6 by the two upper and lower high-strength bolts via the splice plate 9, thereby substantially fixing the beam 1. It is connected to the column 5 in the form of pin connection, and therefore, in the event of an earthquake, as shown in FIG. 1 (a), relative vertical movement of the beam 1 with respect to the column 5 is allowed. A vibration damper 10 is interposed between the lower flange 3 of the beam 1 and a lower diaphragm 7 provided on the column 5.
In the example shown in the figure, two damping dampers 10 are interposed symmetrically on both sides of the web 2 so that the entire beam-column joint is not twisted.

The damping damper 10 in this embodiment is a steel damper whose overall planar shape is L-shaped as shown in FIGS. 1D and 2, and is fixed to the lower surface side of the lower flange 3 of the beam 1. A fixed portion 10a, an arm portion 10b fixed between the lower flange 3 and the lower diaphragm 7, and a damper portion 10c fixed between the fixed portion 10a and the arm portion 10b. It is comprised by.
The fixed portion 10a, the arm portion 10b, and the damper portion 10c are all made of the same steel material (for example, SN400B), but the damper portion 10c is slightly narrower and thinner than the fixed portion 10a and the arm portion 10b. As a result, the cross-sectional area is reduced, whereby the damper portion 10c yields and plastically deforms due to the rotational motion at the above-mentioned beam-column joint, thereby functioning as a damper.

That is, the fixed portion 10a of the vibration damper 10 is fastened and fixed to the lower flange 3 of the beam 1 by two high-strength bolts so as not to rotate relative to each other. However, one end of the arm portion 10b has a lower flange. 3 is pin-joined so as to be horizontally rotatable by one high-strength bolt, and the other end portion extends outward in the beam width direction of the beam 1 and is connected to the lower diaphragm 7 by one high-strength bolt. The damper portion 10c is pin-bonded so as to be horizontally rotatable, and the damper portion 10c is between the fixed portion 10a fixed to the lower flange 3 and one end portion of the arm portion 10b pin-bonded to the lower flange. It has been provided.
By installing the damping damper at the column-beam joint with the above structure, when the relative rotational movement as described above occurs between the column 5 and the beam 1 during an earthquake, the lower flange 3 The arm portion 10b straddling the lower diaphragm 7 is caused to rotate in the horizontal plane as shown in FIG. 1 (d), whereby the damper portion 10c has a shearing force Q as shown in FIG. 2 (a). And a bending moment M acts. Further, since the fixed portion 10a and the arm portion 10b are installed on the same beam flange surface, no axial force is generated, and the damper is not buckled due to the compressive force. As a result, the damper portion 10c is plastically deformed and the vibration energy is absorbed to obtain a vibration damping effect.

  As described above, in the beam end damping structure of the present invention, the vibration energy is absorbed by the damping damper 10 while allowing the relative rotational motion of the beam 1 with respect to the column 5 in the beam-column joint. Since the vibration damping damper 10 having a simple L-shaped flat shape is installed on the lower surface side of the lower diaphragm 7 provided on the lower flange 3 and the column 5 of the beam 1, the vibration damping damper 10 can be obtained. It is not necessary to secure a special space for installing the projector, and it is less likely to be restricted in plan and design like the conventional beam end damping structure shown in Patent Document 1 and Patent Document 2, Interference with the equipment installed around the pillar 5 and the beam 1 can also be avoided.

Further, since the vibration damper 10 according to the present invention is plastically deformed mainly by the shearing force Q and the bending moment M generated in the plane of the damper portion 10c, the vibration damping damper 10 goes out of plane as demonstrated by the later-described analysis and structural experiment. Therefore, it does not require a special stiffening element for preventing buckling as in the case of various conventional vibration damping dampers, so that sufficient simplification and miniaturization can be achieved. This can be realized and is advantageous in terms of cost.
Furthermore, the vibration damper 10 according to the present invention can be easily installed by simply fastening the bolt with the fixing portion 10a and the arm portion 10b being in close contact with the lower flange 3 of the beam 1 and the lower diaphragm 7 of the column 5, respectively. Therefore, it is excellent in workability, and future replacement can be performed easily and without any trouble.
Of course, the damping damper 10 according to the present invention can be designed freely and widely in terms of the rigidity, proof stress, and fatigue life as a damper by setting the material, shape and dimensions of the damper portion 10c as in the case of conventional steel dampers. It can be widely applied to structures of various scales and uses.

FIG. 3 shows another embodiment. In the above embodiment, the upper portion of the web 2 of the beam 1 is pin-bonded to the upper portion of the shear plate 6 so as to allow relative rotation of the beam. The upper flange 4 is fastened to the upper diaphragm 8 provided on the column 5 by a high-strength bolt via the splice plate 11 and the filler plate 12, and the rest is configured in exactly the same manner as in the above embodiment. .
Also in the present embodiment, as in the above embodiment, the beam 1 is joined to the column 5 in a substantially pin-joined form, and relative rotation in the vertical direction is allowed in the event of an earthquake. An excellent damping effect can be obtained by the installed damping damper 10.
Further, in order to enable the relative rotation of the beam 1 with respect to the column 5 as a substantially pin connection, only the upper flange 4 of the beam 1 may be welded to the upper diaphragm 8. Therefore, it functions in the same manner as the above embodiment, and the same effect can be obtained.

"Examination of damper behavior by FEM analysis"
The behavior of two types of damping dampers (LL model and LS model) with the same cross section and different lengths will be examined by FEM analysis.
The model used for the analysis is shown in FIG. The distance between the fulcrums of the arm portion was 120 mm, the L-shaped corner portion was a pin, and the opposite arm end was applied in the horizontal direction. The damper thickness is 9mm, the width is 70mm, and the damper length is 215mm for the LL model and 95mm for the LS model. The steel material used for the analysis is SN400B, and its material characteristics are shown in FIG. The yield strength of the steel was 235 N / mm2, and a bilinear stress-strain relationship was adopted.
As an analysis result, the relationship between the horizontal load of the analysis model and the horizontal displacement of the applied point is shown in FIG. From this result, the LS model with a short damper length has about twice the rigidity of the LL model with a long damper length, and the LS model has a higher yield strength than the LL model after plasticization. It turns out that it is about 1.4 times-1.5 times.
On the other hand, regarding the low cycle fatigue life of steel materials subjected to bending / shearing forces, the Manson-Coffin law expressed by the plastic strain amplitude is considered to hold, so the LL model with a smaller strain at the same displacement is better than the LS model. Is considered to have a long fatigue life.
FIG. 7 shows a buckling deformation diagram. Regarding the buckling load, it is assumed from the results of buckling eigenvalue analysis that the LL model is 987kN and the LS model is 3198kN. No stiffening element is required.

"Examination of restoring force characteristics of beam end by structural experiment"
The result of carrying out a structural experiment using a test piece of about 1/2 scale by simulating the beam end portion according to the structure of the present invention is shown below. FIG. 8 shows an outline of the experiment. The test body had an inverted T shape, the column was fixed horizontally, and a beam having a height of 2000 mm from the surface of the column was repeatedly applied in the horizontal direction with a dynamic hydraulic jack. The damping damper is the same as the above LL model (SN400B, damper thickness 9 mm, width 70 mm, damper length 215 mm, arm support distance 120 mm). The force program is shown in FIG. The period of one cycle is 2 seconds.
In this experiment, the beam web is pin-supported by only one high-strength bolt, and the arm portion of the damping damper is fastened to the lower diaphragm via the bracket (that is, the bracket is fixed to the lower diaphragm). This forms a notch recess), which is substantially equivalent to the above embodiment.
As an experimental result, the bending moment M and the member deformation angle θ at the material end in the applying steps 2, 3, 5, and 7 are shown in FIG. In this experiment, cracks did not occur in the damper portion until θ = about 2%, and stable restoring force characteristics (energy absorption characteristics) were obtained. Further, since the crack was applied to the damper due to the subsequent force and no buckling occurred outside the force, the effectiveness of the present invention was proved by this experiment.

  The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the main point is that the upper part of the beam is rotatably connected to the column, and then the lower flange of the beam and the column A vibration damper is interposed between the lower diaphragm and the steel plate, and a flat L-shaped steel damper consisting of a fixed part, an arm part and a damper part is used as the vibration damper. What is necessary is just to fasten and install with respect to a lower diaphragm, and, as long as it is natural, it is natural that an appropriate design change and application are possible about the specific structure of each part.

DESCRIPTION OF SYMBOLS 1 Beam 2 Web 3 Lower flange 4 Upper flange 5 Column 6 Shear plate 7 Lower diaphragm 7a Notch recessed part 8 Upper diaphragm 9 Splice plate 10 Damping damper 10a Fixed part 10b Arm part 10c Damper part 11 Splice plate 12 Filler plate

Claims (4)

A beam end damping structure in which a damping damper made of steel is installed at the joint between a column and a beam of a structure,
The beam is made of H-shaped steel, and the pillar is provided with a shear plate at a position facing the web of the beam and a lower diaphragm is provided at a position facing the lower flange of the beam, and is provided on the lower diaphragm. Place the tip of the lower flange inside the notch recess,
The upper portion of the web of the beam is pin-joined so as to be rotatable relative to the upper portion of the shear plate in the vertical direction, and the damping damper is interposed between the lower flange of the beam and the lower diaphragm. And
The vibration damper includes a fixed portion that is fastened and fixed to the lower flange, one end of which is pin-joined so as to be horizontally rotatable with respect to the lower flange, and the other end that is on the outer side in the beam width direction of the beam. An arm portion that extends and is pin-joined so as to be horizontally rotatable with respect to the lower diaphragm, and a damper portion that is provided between the fixed portion and one end portion of the arm portion and is plastically deformed by horizontal rotation of the arm portion Beam end damping structure characterized by comprising The beam end damping structure according to claim 1,
Instead of providing an upper diaphragm on the column at a position facing the upper flange of the beam, and pinning the upper part of the web of the beam to the upper part of the shear plate, the tip of the upper flange of the beam A beam end damping structure characterized in that a portion is pin-joined so as to be rotatable relative to the upper diaphragm in the vertical direction. The beam end damping structure according to claim 1 or 2,
The fixed portion, the damper portion, and the arm portion of the vibration damper are all formed of the same material steel, and the damper portion is formed in a smaller cross section than the fixed portion and the arm portion. Characteristic beam end damping structure. The beam end damping structure according to claim 1, 2 or 3,
A beam end damping structure, wherein the damping damper is arranged symmetrically on both sides of the web on the lower surface side of the lower flange of the beam.