JPH0988088A - Construction of vibration isolation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the damage of a pile, a bottom slab and a footing when earthquake load of design force or more works. SOLUTION: When the construction of vibration isolation is applied to a structure 14 with a plurality of piles 10 and a bottom slab 12, the piles 10 are penetrated up to specified depth in the ground 16 respectively. The bottom slab 12 is formed in the lower structure section of the structure 14, and constructed in the ground 16 so as to cover the upper sides of the top ends 10a of each pile 10. The construction of vibration isolation is composed of first vibration-isolation materials 18 and second vibration-isolation materials 20. The first vibration-isolation materials 18 are interposed among the top ends 10a of each pile 10 and the lower end of the bottom slab 12. The bottom slab 12 is parted in the horizontal direction, and the second vibration-isolation materials 20 are interposed to the parted sections.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base isolation structure, and more particularly to a base isolation structure applied to a foundation of a structure.

[0002]

2. Description of the Related Art A pile foundation structure is known as a kind of foundation structure of a structure, and typical examples thereof are shown in FIGS. In the pile foundation structure shown in FIG. 5, the bottom slab 2 of the structure is provided on the upper part of the plurality of piles 1 penetrating into the ground. It is rigidly connected so as to be embedded inside. In the pile foundation structure shown in FIG. 6, the footings 3 of the structure are provided above the plurality of piles 1 penetrating into the ground, and the piles 1 and the footing 3 are provided.
Are rigidly connected so that the pile head portion of each pile 1 is embedded in the footing 3.

That is, in this type of pile foundation structure, it is a principle that the pile 1 and the lower structure portion of the structure such as the bottom slab 2 or the footing 3 are rigidly connected to the pile head. However, the technical problems described below have been pointed out for such a structure.

[0004]

That is, in the case of a rigid joint structure in which the pile head portion is embedded in the bottom slab 2 or footing 3, if the seismic load exceeding the design force acts on the joint portion, the pile 1, the bottom slab 2 or It is expected that footing 3 will be damaged. When the pile 1, the bottom slab 2 or the footing 3 is damaged, the load of the structure is supported by these parts, so it becomes very difficult to repair and reinforce the damaged part.
Not only will the construction cost increase, but if left unattended, it may cause a secondary disaster.

Further, there is also a problem that horizontal displacement and shaking due to an earthquake adversely affect the living environment and facilities of the structure. The present invention has been made in view of such conventional problems, and an object thereof is to prevent damage to piles, bottom slabs, and footings when an earthquake load larger than the design force is applied. The purpose is to provide a seismic isolation structure.

[0006]

In order to achieve the above object, the present invention comprises a pile foundation penetrated into the ground, and a lower structure portion such as a bottom slab or footing provided on the pile foundation. In a seismic isolation structure of a structure, while interposing a first seismic isolation material between the top end of the pile foundation and the lower end of the lower structure portion, the lower structure portion is horizontally divided.
The 2nd seismic isolation material was interposed in this divided part. According to the seismic isolation structure having this configuration, the first seismic isolation member is interposed between the top end of the pile foundation and the lower end of the lower structure portion, and the lower structure portion is horizontally divided to divide the structure. Since the 2nd seismic isolation material is installed in the area where the seismic force is transmitted to the structure, the seismic isolation material is installed twice, and when the seismic load exceeding the design force is applied. First, this seismic load is absorbed and damped by the first seismic isolation material, and further, is absorbed and damped by the second seismic isolation material, and damage to the pile and the lower structure part is prevented. The first and second seismic isolation members may be composed of laminated rubber isolators in which rubber plates and steel plates are alternately laminated.

[0007]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 3
Shows a first embodiment of the seismic isolation structure according to the present invention. The seismic isolation structure shown in the figure has a plurality of piles 10 and a bottom plate 12.
This is the case when applied to the structure 14 provided with. Pile 10
Are respectively penetrated to a predetermined depth in the ground 16.

The bottom slab 12 is a lower structure portion of the structure 14, and is constructed in the ground 16 so as to cover the upper side of the top end 10a of each pile 10. The seismic isolation structure is the first seismic isolation material 1
8 and second seismic isolation material 20. The first seismic isolation material 18 is interposed between the top end 10 a of each pile 10 and the lower end of the bottom plate 12. The second seismic isolation material 20 divides the bottom slab 12 in the horizontal direction, and is interposed in this divided portion.

The seismic isolation members 18, 20 are, in this embodiment,
As shown in FIG. 3 as an example, the laminated rubber isolator 2
It consists of two. The laminated rubber isolator 22 shown in the figure is formed by alternately laminating a disc-shaped rubber plate 22a and a steel plate 22b having substantially the same shape, and mounting end plates 22c and 22d above and below these laminated bodies. Are arranged.

The first seismic isolation material 18 is the pile 1 in this embodiment.
It is formed in substantially the same shape as the horizontal cross section of No. 0, and each end plate 22c, 22d is attached to the top end surface 10a of the pile 10 and the bottom plate 12.
It is attached by fixing it to the lower end surface of each with bolts and nuts. In the second seismic isolation member 20, the horizontal cross section of the bottom plate 12 is relatively large in this embodiment, so that the center of the plurality of laminated rubber isolators 22 is on the intersection of the virtual lattice, as shown in the arrangement state of FIG. The end plates 22c and 22d are attached to the divided section of the bottom plate 12 by fixing them with bolts and nuts.

The laminated rubber isolator is not limited to the structure shown in FIG. 3, but may be a laminated rubber isolator containing a lead plug, or an isolator using a high damping laminated rubber or Teflon. Now, in the seismic isolation structure configured as described above, the top end 10a of the pile 10 and the bottom plate 1
While interposing the first seismic isolation material 18 between the lower end of 2 and
Since the bottom slab 12 is horizontally divided and the second seismic isolation material 20 is interposed in the divided portion, the seismic isolation materials 18 and 20 are doubled in the path through which the seismic force is transmitted to the structure. When the seismic load is installed, and the seismic load exceeding the design force acts, the seismic load is first absorbed and damped by the first seismic isolation material 18, and further,
It is absorbed and damped by the second seismic isolation material 20, and the pile 10 and the bottom plate 12
And damage is prevented.

Further, the seismic isolation material is installed at, for example, the pile 1
If only the part of the top end 10a of 0 is used, a large seismic isolation material is required to absorb the seismic energy, and if it is large, the horizontal displacement will be large and residual displacement due to this will be predicted. As shown in the example, if the seismic isolation materials 18 and 20 are double provided in the path through which the seismic force is transmitted to the structure, the seismic isolation materials 18 and 20 can be prevented from increasing in size, and Can also be reduced in height, which can reduce residual displacement.

FIG. 4 shows another embodiment of the seismic isolation structure according to the present invention, and only the characteristic points will be described below. The embodiment shown in the figure is an example applied to the footing 30 of the structure 14a supported by a plurality of piles 10, and is a first space between the top end 10a of each pile 10 and the lower end surface of the footing 30. The seismic isolation material 18 is interposed. Footing 3
No. 0 is divided in the horizontal direction, and the second seismic isolation material 20a is interposed in this divided portion. First and second
The seismic isolation materials 18 and 20a are composed of a laminated rubber isolator 22 as in the above embodiment. Second seismic isolation material 20a
In this embodiment, is formed in a planar shape having substantially the same size as the horizontal cross section of the footing 30.

Even in the seismic isolation structure thus constructed, the seismic isolation materials 18, 2 are provided in the path through which the seismic force is transmitted to the structure.
Since 0a is doubly interposed, the same effect as that of the above embodiment can be obtained.

[0015]

As described above in detail in the embodiments,
According to the seismic isolation structure of the present invention, the seismic isolation material is doubly interposed in the path through which the seismic force is transmitted to the structure. The load is absorbed and damped by the first seismic isolation material, and further, is absorbed and damped by the second seismic isolation material, and the pile and lower structure (bottom plate, footing)
And damage is prevented.

In addition, since the seismic isolation material is doubly provided in the path through which the seismic force is transmitted to the structure, the structure shakes and horizontal displacement is reduced, and the structure, the living environment, the equipment, and the furniture are fixed. The impact of the earthquake on etc. can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a seismic isolation structure according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional explanatory view showing an example of a seismic isolation material used in the seismic isolation structure according to the present invention.

FIG. 4 is a sectional view showing another embodiment of the seismic isolation structure according to the present invention.

FIG. 5 is an explanatory view showing a connection state between a conventional pile and a bottom slab.

FIG. 6 is an explanatory view showing a state in which a conventional pile and a footing are connected to each other.

[Explanation of symbols]

 10 Pile 10a Top end 12 Bottom plate 14 Structure 16 Ground 18 First seismic isolation material 20, 20a Second seismic isolation material 22 Laminated rubber isolator

Claims (2)

[Claims] 1. A seismic isolation structure for a structure comprising a pile foundation penetrating into the ground and a lower structure portion such as a bottom slab or footing provided on the pile foundation, wherein the top of the pile foundation and the First between the lower end of the lower structure
A seismic isolation structure characterized by interposing a seismic isolation material, dividing the lower structure portion in a horizontal direction, and interposing a second seismic isolation material in the divided portion. 2. The seismic isolation structure according to claim 1, wherein the first and second seismic isolation members are laminated rubber isolators in which rubber plates and steel plates are alternately laminated.