JP7623221B2 - Displacement control device - Google Patents

Description

The present invention relates to a displacement suppression device.

In recent years, there has been a trend toward larger earthquake motions that need to be considered in design, and there is a risk that seismically isolated buildings will collide with retaining walls if designed in the conventional way. As a result, various technologies have been devised to prevent buildings from colliding with retaining walls.

For example, some oil dampers installed to suppress deformation of the seismic isolation layer are of the variable damping type, whose damping force changes with deformation so that the greater the deformation, the greater the damping force. However, since oil dampers are only effective in one direction along the horizontal plane, in order to avoid collisions with the retaining wall in all directions, it is necessary to install variable damping oil dampers in two directions along the horizontal plane.

In addition, the following Patent Document 1 proposes a technology in which a buffer part made of a material such as rubber that is softer than the retaining wall is installed between a displacement-regulating main body part (retaining wall) provided on the lower structure and a part of the upper structure such as a beam of the upper structure, and the part of the upper structure is collided with the buffer part instead of the retaining wall, thereby softening the impact (see Patent Document 1 below).

Patent No. 6327447

However, the configuration of Patent Document 1 has the problem that the seismic isolation clearance is reduced by the thickness of the buffer section (the horizontal protrusion length from the retaining wall). In addition, to avoid collisions in multiple directions along the horizontal surface, it is necessary to install buffer sections in various directions relative to the retaining wall, which results in a large number of installation points.

The present invention was made in consideration of the above circumstances, and provides a displacement suppression device that can suppress excessive displacement in any direction in a horizontal plane with a small number of installation locations.

In order to achieve the above object, the present invention employs the following means.
That is, the displacement suppression device of the present invention is a displacement suppression device installed between a lower structure and an upper structure that is movable relatively to the lower structure, and includes a rubber covering, a chain main body embedded inside the rubber covering and having a plurality of rings connected thereto, a first fixed part provided between the lower structure and one end of the chain main body, and a second fixed part provided between the upper structure and the other end of the chain main body, the chain main body being connected to the lower structure via the first fixed part so as to be rotatable about an axis with the vertical direction as the axial direction, and being connected to the upper structure via the second fixed part so as to be rotatable about an axis with the vertical direction as the axial direction, the first fixed part being composed of a plate-shaped first fixed plate having a mounting hole formed therein and a first pin member inserted into the mounting hole, and the second fixed part being composed of a plate-shaped second fixed plate having a mounting hole formed therein and a second pin member inserted into the mounting hole .

In a displacement suppression device configured in this manner, when the displacement of the seismic isolation layer increases during an earthquake, the chain body, which is made up of multiple connected rings, stretches. Because the chain body is embedded inside the rubber covering, the rubber covering acts as a resistance when the chain body stretches. In addition, the chain body can stretch in any direction. Therefore, with a small number of installation locations, excessive displacement in any direction in the horizontal plane can be suppressed.
In addition, the chain body is connected to the lower structure and the upper structure so as to be rotatable about an axis that is axially aligned in the vertical direction, so that the chain body can be smoothly oriented in any direction during an earthquake.

The displacement suppression device of the present invention can suppress excessive displacement in any direction in a horizontal plane with a small number of installation locations.

1 is a schematic diagram showing a displacement suppression device according to an embodiment of the present invention; 4 shows the relationship between load and deformation of a displacement suppression device according to an embodiment of the present invention. 1 is a diagram showing how a chain body of a displacement suppression device according to an embodiment of the present invention is fixed to a lower structure; A figure showing a state in which the deformation of the seismic isolation layer increases and the displacement suppression device of one embodiment of the present invention is extended. 11A to 11C are diagrams showing the characteristics of a retaining wall in an analysis of a displacement suppression device according to one embodiment of the present invention. 13 is a diagram showing characteristics of a buffer chain in an analysis of a displacement suppression device according to one embodiment of the present invention. FIG. 4 is an analysis result of a displacement suppression device according to an embodiment of the present invention, showing a maximum response acceleration distribution. 4 is an analysis result of a displacement suppression device according to one embodiment of the present invention, showing the maximum response story shear force distribution. 13 is an analysis result of a displacement suppression device according to one embodiment of the present invention, showing deformation of the seismic isolation layer.

A displacement suppression device according to an embodiment of the present invention will be described with reference to the drawings.
Fig. 1 is a schematic diagram showing a displacement suppression device according to an embodiment of the present invention. As shown in Fig. 1, a seismic isolation device (not shown) and a buffer chain 1, which is an example of a displacement suppression device, are installed between a foundation (lower structure) 11 and a building (upper structure) 16. A seismic isolation layer 12 is provided between the foundation 11 and the building 16.

The lower part of the seismic isolation device is fixed to the upper part of the foundation 11, and the upper part of the seismic isolation device is fixed to the lower part of the building 16. The seismic isolation device has a well-known configuration, such as laminated rubber or sliding bearings. The foundation 11 and the building 16 are capable of moving relative to each other in the horizontal direction.

The buffer chain 1 suppresses excessive horizontal displacement of the seismic isolation layer 12. The buffer chain 1 includes a chain body 2, a first fixed part 4, and a second fixed part 5.

The chain body 2 is a product of a well-known configuration that is commercially available as a bridge fall prevention device. The chain body 2 has a chain body 20 and a rubber covering body 30.

The chain body 20 has multiple rings 21. The rings 21 are, for example, steel bars processed into an oval shape. The chain body 20 is shaped such that the axes of adjacent rings 21 are connected at right angles to each other. In the normal state shown in FIG. 1, the distance between adjacent rings 21 can be shortened or lengthened. In other words, in the normal state, the chain body 20 is not fully stretched and is in a slack state.

The rubber covering body 30 covers at least a portion of the longitudinal direction of the chain body 20. In this embodiment, the rubber covering body 30 covers the end of the chain body 20 on the side of the first fixed part 4. The rubber covering body 30 may cover the end of the chain body 20 on the side of the second fixed part 5, or may cover the longitudinal center of the chain body 20.

In this embodiment, the rubber covering body 30 is formed from a rubber material such as natural rubber or synthetic rubber that has resistance and repulsion. The rubber covering body 30 is formed in a substantially cylindrical shape. The shape of the rubber covering body 30 is not limited to a cylindrical shape, and may be a prismatic column or a cross-shaped cross section. The rubber covering body 30 is solidified with a gap D (see FIG. 3) between adjacent rings 21. At least a portion of the chain body 2 is embedded inside the rubber covering body 30.

When the chain body 20 is fully stretched, it comes into contact with the rubber covering 30. The results of a static tensile test of the elongation and load of the chain body 20 are shown in Figure 3. As shown in Figure 3, the load increases gradually as the chain body 20 stretches.

A lower mounting portion 13 is provided on the upper part of the foundation 11. The lower mounting portion 13 protrudes upward from the upper part of the foundation 11. An upper mounting portion 18 is provided on the lower part of the building 16. The upper mounting portion 18 protrudes downward from the lower part of the building 16.

The first fixing part 4 is a fixing means for fixing one end (lower side) of the chain body 20 to the lower mounting part 13. The second fixing part 5 is a fixing means for fixing the other end (upper side) of the chain body 20 to the upper mounting part 18.

FIG. 3 is a diagram showing the fixing of the chain body 20 to the lower attachment portion 13. As shown in FIG.
3, the ring 21a is formed in a semi-annular shape at one end of the chain body 20. An end plate 22 is provided at the end of the ring 21a so as to close the semi-annular ring 21a. The end plate is made of, for example, a steel material.

As shown in FIG. 1, the first fixing portion 4 has a first fixing plate 41 and a first pin member 42. The first fixing plate 41 is connected to the end plate 22. The first fixing plate 41 is installed on the upper side of the lower mounting portion 13. The first fixing plate 41 is formed in a plate shape. The plate surface of the first fixing plate 41 faces the vertical direction. The first fixing plate 41 is formed of, for example, a steel material.

The first fixed plate 41 has an attachment hole (not shown). The first pin member 42 is inserted through the attachment hole of the first fixed plate 41 and is fixed to the lower attachment portion 13. The first pin member 42 faces in the vertical direction. The first fixed plate 41 is rotatable around the axial direction (vertical direction) of the first pin member 42.

The other end of the chain body 20 is configured in the same manner as the one end, and a description thereof will be omitted. The second fixing part 5 has a second fixing plate 51 and a second pin member 52. The second fixing plate 51 is connected to the end plate 22 at the other end of the chain body 20. The second fixing plate 51 is installed below the upper mounting part 18. The second fixing plate 51 is formed in a plate shape. The plate surface of the second fixing plate 51 faces the vertical direction. The second fixing plate 51 is formed, for example, from a steel material.

The second fixing plate 51 has an attachment hole (not shown). The second pin member 52 is inserted through the attachment hole of the second fixing plate 51 and is fixed to the upper attachment portion 18. The second pin member 52 faces in the vertical direction. The second fixing plate 51 is rotatable around the axial direction (vertical direction) of the second pin member 52.

In this way, the chain body 20 is connected to the foundation 11 and the building 16 so that it can rotate around an axis with the vertical direction as the axial direction.

During an earthquake, the building 16 moves in any direction on the horizontal plane. Both ends of the buffer chain 1 can rotate around an axis that is axially aligned vertically so that it can follow the behavior of the building 16.

FIG. 4 is a diagram showing a state in which the deformation of the seismic isolation layer 12 becomes large and the buffer chain 1 is stretched.
As shown in Figure 4, when the deformation of the seismic isolation layer 12 becomes large during an earthquake, the chain body 20 stretches so that the gap D between the adjacent rings 21 of the chain body 20 disappears. It is preferable that the vertical separation distance (installation vertical distance) H1 between the lower mounting part 13 and the upper mounting part 18 is as close as possible because only pure shear force acts on the first fixing part 4 and the second fixing part 5.

Next, the effectiveness of the buffer chain 1 of this embodiment was verified through analysis.
The analysis method involves modeling a seismically isolated building as a system of masses, and inputting the observed waves from Nishihara Village during the Kumamoto earthquake to confirm the response value. There are three analysis cases: 1. Regular seismic isolation structure, 2. Installation of only a retaining wall, and 3. Installation of a retaining wall with a buffer chain (this embodiment) connected. In the analysis results shown in Figures 7 to 9, "1. Regular seismic isolation structure" is represented as "regular", "2. Installation of only a retaining wall" is represented as "retaining wall", and "3. Installation of a retaining wall with a buffer chain (this embodiment) connected" is represented as "this embodiment".

The target building is an 11-story reinforced concrete building with an intermediate-story seismic isolation layer on the third floor above ground. The following settings were made: base fixed primary natural period: 1.8 seconds, seismic isolation primary period: 3.9 seconds, total building weight: 7,193 t, seismic isolation layer damping constant: 20%.

The retaining wall was placed at a position where the seismic isolation layer deformation was 750 mm, and the stiffness of the retaining wall was calculated as the stiffness of a cantilever concrete wall and set at 2,400 kN/mm. The characteristics of the retaining wall are shown in Figure 5.

The buffer chains are installed so that they start to operate when the seismic isolation layer deforms by 600 mm. The stiffness characteristics of each buffer chain are shown in Figure 6. The buffer chains' primary stiffness was set to 1 kN/mm, secondary stiffness to 10 kN/mm, and tertiary stiffness to 30 kN/mm.

The buffer chain is installed in an amount that provides a resistance of 7% of the total building weight. In other words, for the target building, this is 7% of 7,193 t, so 503.5 t = 4,934.3 kN. The buffer chain is activated at 600 mm, and when it reaches 750 mm, it becomes in series with the retaining wall and provides resistance.

The input earthquake motion is for Nishihara Village. If 100% is input, the high-damping rubber used in the building's seismic isolation device will exceed 400% and the analysis cannot continue, so a magnification of 65% is used.

An example of the analysis results is shown in Figures 7 to 9. In the absence of a retaining wall, the seismic isolation layer of the target building deforms to 830 mm (see Figure 9). If a retaining wall is placed at 750 mm from this building, the building will collide with the wall, and the response acceleration will be more than doubled ^to 1,400 cm/s2 (see Figure 7). In contrast, by installing the buffer chain so that it is effective from the 600 mm position, the seismic isolation layer deformation is 750 mm or less (see Figure 9) and the response acceleration is 800 cm/ ^s2 (see Figure 7), which is more than 40% lower than if the building were to collide with the retaining wall. However, as shown in Figure 8, the story shear force is almost the same as when the building collides with the retaining wall. It can be seen that the buffer chain can reduce the seismic isolation layer deformation and response acceleration.

One buffer chain can withstand up to 1,500 kN, making it a high-strength seismic isolation device. One buffer chain is effective in any direction on the horizontal plane, so the number of installation locations can be reduced. The load rises gradually as shown in Figure 2, making it possible to reduce the response acceleration compared to colliding with a retaining wall. By adjusting the length of the chain, it is possible to stop the load at any desired deformation of the seismic isolation layer.

In the buffer chain 1 configured in this manner, when the displacement of the seismic isolation layer 12 increases during an earthquake, the chain body 20, to which multiple rings 21 are connected, stretches. Because the chain body 20 is embedded inside the rubber covering 30, the rubber covering 30 acts as a resistance when the chain body 20 stretches. In addition, the chain body 20 can stretch in any direction. Therefore, excessive displacement in any direction in the horizontal plane can be suppressed with a small number of installation locations.

In addition, because one buffer chain 1 is effective in any direction, the installation location is 1/8 that of the prior art (Patent Publication No. 6327447), saving space and reducing costs.

The chain body 20 is connected to the foundation 11 and the building 16 so that it can rotate around an axis that is axially aligned in the vertical direction. Therefore, in the event of an earthquake, the chain body 20 can be smoothly oriented in any direction.

The assembly procedures and the shapes and combinations of the components shown in the above-mentioned embodiments are merely examples, and may be modified in various ways based on design requirements, etc., without departing from the spirit of the present invention.

For example, the buffer chain 1 can be applied not only to newly constructed structures but also to existing seismic isolation structures, and can also be installed in the seismic isolation layer of existing seismic isolation structures.

1...Buffer chain (displacement suppression device)
2... Chain body 4... First fixed portion 5... Second fixed portion 11... Foundation (lower structure)
16...Building (superstructure)
20: Chain body 21: Ring 30: Rubber covering

Claims (2)

A displacement suppression device installed between a lower structure and an upper structure that is movable relative to the lower structure,
A rubber covering;
a chain body having a plurality of rings connected thereto and embedded within the rubber covering;
A first fixing portion provided between the lower structure and one end of the chain body;
a second fixing portion provided between the upper structure and the other end of the chain body,
the chain body is connected to the lower structure via the first fixing portion so as to be rotatable about an axis with the vertical direction as an axial direction, and is connected to the upper structure via the second fixing portion so as to be rotatable about an axis with the vertical direction as an axial direction,
The first fixing portion includes a first fixing plate having a mounting hole and a first pin member inserted into the mounting hole,
The second fixing portion is a displacement suppression device constituted by a plate-shaped second fixing plate having a mounting hole formed therein, and a second pin member inserted into the mounting hole . The first fixed plate and one end of the chain body are connected by a semi-annular ring,
The displacement suppression device according to claim 1 , wherein the second fixed plate and the other end of the chain body are connected by a semi-annular ring.

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