JP7357504B2 - Seismic isolation structure of buildings - Google Patents

Description

The present invention provides an intermediate floor between the upper structure and the lower structure so that a multi-story building is divided into an upper structure and a lower structure, and the upper structure functions as a weight of TMD. Regarding the seismic isolation structure of buildings in which seismic isolation bearings are installed.

As a seismic isolation structure for such a building, it is known that a seismic isolation rubber bearing made of laminated rubber is used as the seismic isolation bearing. The reality is that laminated rubber with normal horizontal rigidity has been selected and used. However, in that case, although the vibrations of the upper structure can be suppressed, the vibrations of the lower structure become larger, and there is room for improvement in this respect.
Therefore, conventionally, as the laminated rubber for seismic isolation bearings, laminated rubber having horizontal rigidity calculated by a unique mathematical formula is used, and furthermore, a damping force generating means (oil A structure has been proposed in which the vibration of the lower structure is suppressed in addition to the vibration of the upper structure by using a damper (for example, see Patent Document 1).

JP 2007-2455 A (especially see FIG. 1(B) and paragraph [0037])

However, the conventional technology described in Patent Document 1 requires laminated rubber having special horizontal rigidity, so it is not always possible to use commercially available laminated rubber for seismic isolation as is, and in some cases, This requires special ordering, which may result in higher material costs. Furthermore, a damping force generating means is also essential, and it is not always possible to use a commercially available damping force generating means as is, and there is a possibility that it may be custom-made.

The present invention has focused on such conventional problems, and its purpose is to improve the structure of superstructures even though commercially available seismic isolation rubber bearings can be used without requiring special seismic isolation rubber bearings. The object of the present invention is to provide a base isolation structure for a building that can effectively suppress the deformation of a substructure due to vibration.

A first characteristic configuration of the present invention is that a multi-story building is divided into an upper structure and a lower structure, and the upper structure and the lower structure are separated so that the upper structure functions as a weight of TMD. A seismic isolation structure for a building in which seismic isolation bearings are installed on the intermediate floor between
The seismic isolation bearing is a seismic isolation rubber bearing of a series of natural rubber-based laminated rubber that has a higher horizontal rigidity as the axial force is larger in the product and does not have a damping force generating means separate from the laminated rubber , As the rubber bearing, a product is used that has a horizontal rigidity that is 2.0 to 4.0 times higher than the horizontal rigidity of the product used in response to the axial force calculated from the weight of the superstructure. At the point.

According to this configuration, the seismic isolation bearing installed on the intermediate floor of the building is a seismic isolation rubber bearing, and the normal horizontal rigidity corresponding to the axial force that should normally be borne is 2.0 to 4.0. Because it has twice as high horizontal rigidity, for example, even if commercially available seismic isolation rubber bearings are used, it is possible to effectively suppress not only the deformation caused by vibrations of the upper structure, but also the deformation of the lower structure. .
That is, as will be explained in detail later, as a result of repeated various simulations and analyzes by the present inventors, it was found that the seismic isolation rubber bearing has 2. The fact that when the horizontal rigidity is as high as 0 to 4.0 times, it is possible to suppress the vibrations of the lower structure in addition to the vibrations of the upper structure, even without using damping force generating means such as oil dampers. I came to the conclusion that
The present invention is based on such new knowledge, and although a commercially available seismic isolation rubber bearing can be used without the need for a special seismic isolation rubber bearing, it is possible to prevent vibrations in the upper and lower structures. This makes it possible to effectively suppress the deformation caused by this.

A second feature of the present invention is that the horizontal rigidity of the product used as the seismic isolation rubber support is 2.5 to 3.0 in accordance with the axial force calculated from the weight of the upper structure. The point is that products with twice as high horizontal rigidity are used .

According to this configuration, the seismic isolation rubber bearing has a horizontal rigidity that is 2.5 to 3.0 times higher than that of a normal horizontal rigidity. The vibrations of the upper structure and the lower structure can be reliably suppressed without providing any damping force generating means.

A third feature of the present invention is that the intermediate floor is set at a height of 1/2 to 1/4 from the top of the multi-story building.

According to this configuration, the intermediate floor where the seismic isolation rubber bearing is installed is set at a height of 1/2 to 1/4 from the top of the multi-story building, so the upper and lower structures of the building are In other words, the mass of the upper structure, which functions as the weight of the TMD, is close to ideal with respect to the mass of the lower structure, and the upper structure, lower structure, and seismic isolation rubber bearing The vibration system made up of these functions as desired and enables reliable vibration control.

A fourth characteristic configuration of the present invention is that the intermediate floor is set at a height of about ⅓ from the top of the multi-story building.

According to this configuration, the intermediate floor where the seismic isolation rubber bearing is installed is set at a height of about 1/3 from the top of the multi-story building, so the upper structure, the lower structure, and the seismic isolation The vibration system made up of rubber bearings will be in a state closer to the ideal, making even more reliable vibration control possible.
In particular, if the seismic isolation rubber bearing has a horizontal rigidity that is 2.5 to 3.0 times higher than normal horizontal rigidity, the seismic isolation rubber bearing will have even more significant vibration control due to the cooperation with the ideal seismic system. You can expect good results.
A fifth characteristic configuration of the present invention is that the seismic isolation rubber bearing is a natural rubber-based laminated rubber NH series manufactured by Bridgestone Corporation.

A schematic diagram showing the base isolation structure of a building according to the present invention Graph showing the vibration damping effect of the present invention Graph showing vibration damping effect of comparative example Graph showing vibration damping effect of comparative example

Embodiments of a seismic isolation structure for a building according to the present invention will be described based on the drawings.
As shown in FIG. 1, the seismic isolation structure of a building of the present invention is such that, for example, a 22-story multi-story building 1 is divided into an upper structure 2 of 15 floors or higher and a lower structure 3 of 14 floors or lower. A seismic isolation rubber bearing 5 is installed on the intermediate floor 4 between the upper structure 2 and the lower structure 3 so that the upper structure 2 functions as a weight for a TMD (tuned mass damper). will be installed. That is, on the intermediate floor 4 between the 14th and 15th floors, a seismic isolation rubber support 5 is installed interposed in each of the plurality of columns 6.
As each seismic isolation rubber bearing 5, a commercially available seismic isolation rubber bearing 5 is used, which has a horizontal rigidity 2.0 to 4.0 times higher than the normal horizontal rigidity corresponding to the axial force that should normally be borne. be done.

As a result of repeated analysis by the inventors of various simulations, it was found that, as mentioned above, the seismic isolation rubber bearing 5 has a normal horizontal rigidity of 2.0 to 4. It has been found that vibrations of the upper structure 2 and lower structure 3 of the multi-story building 1 can be effectively suppressed by using the seismic isolation rubber bearing 5 which has a horizontal rigidity as high as .0 times. Ta.
To explain an example of the simulation, the interstory deformation angle of each floor was analyzed for a 22-story multi-story building with and without seismic isolation rubber bearings 5 installed. The results are the graphs shown in Figures 2 to 4. In each graph, the vertical axis shows the building level, the horizontal axis shows the interstory deformation angle (x 1/1000 rad), and 〇 and ● indicate the 2 The results are shown when specific vibrations from two earthquakes are applied. In addition, the seismic isolation rubber support 5 shall be installed between the 14th and 15th floors, and in that case, the weight of the superstructure 2 on the 15th floor and above is 13.256 (t) x 9.8 (N/ kg), and if each of the 19 columns 6 is installed with a seismic isolation rubber bearing 5 interposed, the weight per seismic isolation rubber bearing 5 is 13.256 (t) x 9.8 (N /kg)/19≒6837 (kN).

The graph in Figure 3 shows the case of an ordinary multi-story building that does not have seismic isolation rubber bearings 5 installed, and in both 〇 and ●, large deformations exceeding the reference line set at 12/1000 rad were confirmed on floors near the 15th floor. In particular, remarkable deformation is confirmed for 〇.
The graph in FIG. 4 shows a case where a seismic isolation rubber bearing 5 having normal horizontal rigidity commensurate with the axial force that should normally be borne is installed. For example, if we use the NH series of natural rubber laminated rubber manufactured by Bridgestone Corporation, the axial force borne by one seismic isolation rubber bearing 5 is 6837 (kN), so the axial force is 7630 (kN) in consideration of safety. A seismic isolation rubber bearing 5 of NH090 G 4 (product name) of kN) will be used, and the seismic isolation rubber bearing 5 has a horizontal rigidity of 1.26 (×1000 kN/m). When NH090 G 4 is installed, as is clear from the graph in Figure 4, a remarkable seismic control effect is confirmed on the upper floors, including floors around the 15th floor, but on the lower floors below the 5th floor, A very large deformation exceeding the reference line is observed.
In addition, in the graph of this FIG. 4 and the graph of FIG. 2 mentioned later, the part where the line of a graph divides is the floor near the intermediate floor where the seismic isolation rubber support 5 was installed.

On the other hand, the graph in FIG. 2 shows the case where the seismic isolation rubber bearing 5 is installed, which has a horizontal rigidity approximately 2.7 times higher than the normal horizontal rigidity corresponding to the axial force that should normally be borne. This is the case. In other words, if the NH series of natural rubber laminated rubber manufactured by Bridgestone Corporation is used, the axial force borne by one seismic isolation rubber bearing is 6837 (kN), and normally the axial force is 7630 (kN) and the horizontal NH090 G 4, which has a rigidity of 1.26 (×1000 kN/m), should be used, but the horizontal rigidity is 3.46 (×1000 kN/m), and the normal horizontal rigidity is 3.46 ÷ 1.26 ≒ The seismic isolation rubber bearing 5 of NH150 G 4 (product name), which has 2.7 times the horizontal rigidity, will be used and has an axial force of 26,500 (kN).
In the case of the present invention, as is clear from the graph in Figure 2, even though damping force generating means such as oil dampers are not used together, no major deformation is observed on the lower floors, and almost all floors meet the standards. Good seismic damping effects below the line are confirmed.

As a result of trying various other simulations, we found that the horizontal rigidity of the seismic isolation rubber bearing 5 is 2.0 to 4.0 times higher than the normal horizontal rigidity that is commensurate with the axial force that should normally be borne. It has been found that those having a horizontal rigidity 2.5 to 3.0 times higher than normal horizontal rigidity are particularly preferable.
Similarly, the intermediate floor 4 on which the seismic isolation rubber support 5 is installed is preferably set at a height of 1/2 to 1/4 from the top of the multi-story building 1. It has been found that it is preferable to set the height of the floor to about 1/3 from the top.
Note that when implementing the present invention, it is not necessarily necessary to use a damping force generating means such as an oil damper, but it is possible to use a damping force generating means in combination to further improve the damping effect.

1 Multi-story building 2 Upper structure 3 Lower structure 4 Intermediate floor 5 Seismic isolation rubber bearing

Claims (5)

A multi-story building is divided into an upper structure and a lower structure, and seismic isolation bearings are installed on the intermediate floor between the upper structure and the lower structure so that the upper structure functions as the weight of TMD. A seismic isolation structure for buildings in which
The seismic isolation bearing is a seismic isolation rubber bearing of a series of natural rubber-based laminated rubber that has a higher horizontal rigidity as the axial force is larger in the product and does not have a damping force generating means separate from the laminated rubber , As the rubber bearing, a product is used that has a horizontal rigidity that is 2.0 to 4.0 times higher than the horizontal rigidity of the product used in response to the axial force calculated from the weight of the superstructure. Seismic isolation structure for buildings. As the seismic isolation rubber bearing, a product having a horizontal rigidity 2.5 to 3.0 times higher than the horizontal rigidity of the product used in response to the axial force calculated from the weight of the superstructure is used. The seismic isolation structure of a building according to claim 1 , which is used . 3. The seismic isolation structure for a building according to claim 1, wherein the intermediate floor is set at a height of 1/2 to 1/4 from the top of the multi-story building. 4. The seismic isolation structure for a building according to claim 3, wherein the intermediate floor is set at a height of about ⅓ from the top of the multi-story building. The seismic isolation structure for a building according to any one of claims 1 to 4, wherein the seismic isolation rubber bearing is a natural rubber-based laminated rubber NH series manufactured by Bridgestone Corporation.

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