JPH06323034A - Base isolation structure for high-rise building - Google Patents

Abstract

PURPOSE:To isolate the deflection vibration of a long period by installing an extensible/compressible longitudinal vibration absorbing support and a longitudinal direction damper in common at the leg part of a high-rise building, and installing a shearing resistance member at the center part. CONSTITUTION:At the leg part of a high-rise building 1 which generates a bending deformation, an extensible/compressible longitudinal vibration absorbing support 2 consisting of a laminated rubber, etc., having a low rigidity and a longitudinal directional damper 3 consisting of an elastoplastic body of viscoelastic body are used. Further, at the center leg part, a shearing resistance member 4 is installed, and the rigidity in the horizontal direction accompanied with the movement of the ground surface is improved. The deflection vibration of the high-rise building which shows a kind of leaf spring dehavior is isolated. Accordingly, the deflection vibration of a long period can be softened for.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation structure for a high-rise building which is excellent in bending deformation.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, seismic energy absorption by shear deformation of a shear vibration absorption bearing 6 provided on a leg portion of a building and horizontal damping by an elastic-plastic damper or viscoelastic body made of steel or the like. The damper 7 was also used to construct the seismic isolation structure.

[0003]

The conventional seismic isolation structure has a relatively small height with respect to the cross-sectional area of the building, and is effective for a building in which the building does not bend much due to seismic force. Since the bending deformation of the building in the axial direction is small, the building is regarded as a single rigid body and behaves in shear vibration with the ground. Therefore, the vibration is absorbed by the laminated rubber bearing, the elastic-plastic damper, and the viscous damping device using the viscoelastic body.

However, when the height is higher than a certain level with respect to the cross-sectional area of a building, the behavior of vibration becomes completely different from the rigid body vibration seen in a building with a low height. A building whose height is higher than the cross-sectional area of the building behaves like a leaf spring. In other words, the spring constant of flexural vibration, which is regarded as in the case of the statically indeterminate beam with central free support, is the nth power (n>
It decreases in inverse proportion to 1). Therefore, a large bending vibration is generated with a small external force. Further, the frequency of a building with a high height is low because the spring constant is small as described above, and therefore the cycle of vibration is large. This flexural vibration with a large cycle causes the leg to extend and compress static static vibration on the bearing, and the entire building becomes rotational vibration. It is an object of the present invention to isolate the flexural vibration by absorbing this rotational vibration.

[0005]

[Means for Solving the Problems] As a whole building, the leg of the building is combined with a support made of laminated rubber or the like having low rigidity in the axial direction and a vertical damper made of an elastoplastic or viscoelastic body. Absorbs rotational vibration. By absorbing the rotational vibration, flexural vibration as a beam is isolated. In addition, a shear resistance member is arranged on the central leg of the building to prevent an extreme decrease in shear rigidity.

[0006]

1 is a model diagram of an embodiment of the present invention. In addition, FIG. 3A shows the high-rise building 1 by a single line. The building 1, which has a height higher than the cross-sectional area of the building, behaves like a statically unsupported beam that supports the center freely. The spring constant is
Since the height is inversely proportional to the n-th power (n> 1), the flexural vibration is generated by a small external force. Moreover, for example, if the propagation speed of vibration is estimated to be 35 m / sec, it is 70 m.
The vibration cycle of a building with a height of 2 is 2 sec, which is far below the range where the conventional shear vibration absorption bearing 6 can be isolated. Moreover, the behavior of vibration is inherently low in the conventional building 5,
That is, it is different from the shear vibration between the ground and the crust, which is regarded as a rigid body. The vibration of the high-rise building 1 is basically bending vibration, and an example of the basic vibration is shown in a model diagram 3 (b). Therefore, it suffices if the bearings of the legs of the building are adapted to cope with longitudinal vibrations such as extension and compression instead of shear vibrations. For this reason, a stretchable / compressible longitudinal vibration absorbing bearing 2 and a longitudinal damping damper 3 are provided. The state in which the stretchable / compressible longitudinal vibration absorbing bearing 2 is applied is shown in FIGS. 4 (a) and 4 (b). In the figure, the bearing appears to rotate and tilt, but the actual building has a bottom area as shown in Fig. 5 and there is not one bearing, so the behavior of the stretchable / compressible longitudinal vibration absorbing bearing is Figure 5 from the perspective of the entire building
The rotational vibration is as shown in Fig. 4, which is equivalent to the behavior shown in Figs. When (a) and (b) of FIG.
As shown in (c), flexural vibration can be avoided. Of course, since the leg portions of the building have shear vibrations associated with the movement of the ground surface and the horizontal rigidity cannot be extremely reduced, the shear resistance member 4 is arranged at the center of the leg portions of the building as shown in FIG. A vertical viscoelastic body or a viscous damping damper 3 is provided in parallel with the stretchable / compressible vertical vibration absorption support 2 to isolate the high-rise building from seismic isolation.

[0007]

1 shows a seismic isolation structure for a high-rise building 1 according to the present invention.

As shown in FIG. 2, the conventional structure concentrates the horizontal deformation on the legs of the building, whereas the seismic isolation structure of the present invention concentrates the rotational deformation on the legs. There is.
As the stretchable / compressible vertical vibration bearing 2, one having a low rigidity in the vertical direction is used, and the required number of vertical damping dampers 3 are arranged in parallel with the stretchable / compressible vertical vibration bearing 2 in the vertical direction. Usually, the horizontal deformation is too large only by itself, so that the member 4 which resists shearing is arranged to suppress the horizontal deformation so that the rotational deformation is predominant.

[0009]

The effect of the present invention enables seismic isolation of flexural vibrations of a long period of about 2 sec or more in a high-rise building, which has hitherto been impossible.

[Brief description of drawings]

FIG. 1 is a diagram showing a seismic isolation structure for a high-rise building according to the present invention.

FIG. 2 is a view showing a conventional seismic isolation structure for a low-height building.

FIG. 3 is a model diagram showing flexural vibration of a high-rise building.

FIG. 4 is a diagram schematically showing how flexural vibration is isolated.

FIG. 5 is a diagram showing how the legs of a high-rise building are rotationally deformed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... High-rise building, 2 ... Stretching / compressible longitudinal vibration absorption support, 3 ... Longitudinal damping damper, 4 ... Shear resistance member, 5 ... Building with low height, 6 ... Shear vibration absorption bearing, 7 ... Horizontal damping damper

Claims (1)

[Claims] 1. A stretchable / compressible longitudinal vibration absorbing bearing 2 and a longitudinal damping damper 3 are installed together on a leg portion of a high-rise building 1, and a shear resistance member 4 is attached to the leg portion of the high-rise building. A seismic isolation structure for high-rise buildings, characterized by being installed.