JPH0643762B2 - Floating seismic isolation structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a floating isolation system in which a device having a seismic isolation effect against seismic force is provided under a rigid structure such as a reinforced concrete structure. Regarding seismic structure.

[Conventional technology]

Many building structures are built directly on the ground by solid foundations or pile foundations. Therefore, when an earthquake occurs, a large seismic wave will be transmitted to the building.
In other words, the building requires a strict seismic design,
The columns and beams will have large cross-sectional dimensions. Therefore, the amount of reinforcing bars and the amount of steel frames increase, which is one of the causes of the increase in the construction cost of the building. Further, in a building having a solid foundation, the problem of uneven settlement occurs, which causes the building to tilt or collapse over a long period of time.

By the way, there is a seismic isolation structure as a means to solve such a problem. This is to reduce the input of seismic force to the building itself, and at the same time, to disperse and attenuate the energy by viscous material to facilitate the structural design of the building.

Conventionally, for example, as a building having this type of seismic isolation structure, a rigid structure is installed so that its lower surface forms a predetermined space with the ground, and the rigid structure is installed between the rigid structure and the ground. It is known that a plurality of horizontal seismic isolation devices are installed in a discrete manner so that the vertical load of a rigid structure can be supported in the space.

[Problems to be solved by the invention]

However, a structure having a conventional seismic isolation structure is one in which a plurality of horizontal seismic isolation devices are discretely attached to the bottom of the structure, and the horizontal seismic isolation device is used for all vertical loads of the structure. To receive. Therefore, the life of the entire building is also influenced by that of the horizontal seismic isolation device.

Here, considering the horizontal seismic isolation device,
The horizontal seismic isolation device has many problems in its mechanical structure and materials. For example, the material is deteriorated due to corrosion and bacterial rot, and it is lacking in durability and reliability such as deterioration over time and deterioration under high stress.

The present invention has been made in view of the above circumstances. By receiving most of the vertical load of a building by a seismic isolation device other than the horizontal seismic isolation device, the entire building has greater durability, reliability and stability. The purpose of the present invention is to provide a seismic isolation structure that has the property of improving the seismic isolation structure and can extend its life.

[Means for solving problems]

This invention provides a foundation board in the ground and a wall standing around this foundation board so as to surround the foundation board, and inside the wall and above the foundation board, A structure is arranged so that a space is formed therebetween, and a horizontal seismic isolation device that supports the structure from the foundation board is arranged between the structure and the foundation board, and the space is formed. In the portion, a fluid material that supports 90 to 95% of the weight of the structure by buoyancy is interposed, and fluid material supply / discharge means that can adjust the liquid level of the fluid material is provided. .

The fluid material used in the present invention includes asphalt, water, bentonite liquid, oil, or the like.

Further, in the present invention, in the space between the structure and the wall, another type of fluid material having a smaller specific gravity than the fluid material interposed in the space between the structure and the foundation board is used. It is desirable to float and fill the material.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. The embodiment shown in these figures is a case where the present invention is applied to a high-rise building having a rigid structure constructed on relatively good ground.

First, FIG. 1 is a diagram showing an entire embodiment of the present invention, in which reference symbol A is ground and A1 is buried soil. B is a structure, B1 is a structure foundation (hereinafter abbreviated as a foundation), and B2 is a structure upper part. 1 is a foundation board, 2 is a horizontal seismic isolation device, 3 is a structure foundation board, 4 is asphalt used as a relatively viscous fluid material, 5 is a wall, 6 is a structure foundation board (hereinafter referred to as the foundation side) (Abbreviated as a board), 7 is water used as another fluid material.

In the present embodiment, most of the load of the structure B is made up of two types of fluid materials, namely asphalt 4 which is a fluid material having high viscosity and water 7 which is another fluid material having a lighter weight (small specific gravity). It is designed to be supported by buoyancy,
Moreover, the amount of the water 7 as a lightweight fluid material can be freely adjusted by increasing or decreasing the fluid material by a fluid material supplying / discharging means such as a pump (not shown), thereby adjusting the buoyancy acting on the structure B. It is supposed to be possible.

2 to 4 are views for explaining the procedure for constructing the structure B including the seismic isolation device.

(I) First, as shown in FIG. 2, the ground A is excavated in the shape of a dish having a horizontally spread bottom surface. At the bottom of the excavated hole, a thin plate-like foundation board 1 which is a solid foundation is placed. On the placed foundation board 1, a plurality of horizontal seismic isolation devices 2, 2, ... For supporting the upper structure B are separately installed at predetermined locations.

(Ii) Next, as shown in FIG. 3, the structure foundation board 3 is installed above the horizontal seismic isolation devices 2, 2 ,.
A box-shaped base portion B1 having a base side board 6 on the upper portion thereof and having a space formed therein is constructed. Spaces are formed between the constructed foundation board 1 and the structure foundation board 3 and between the wall 5 and the foundation side board 6, respectively. The space formed between the foundation board 1 and the structure foundation board 3 is filled with very soft asphalt 4 having a honey degree at a temperature of 15 ± 2 ° C.
Further, water 7 is filled in the upper space, that is, the space formed by the inner wall 5 and the foundation side wall 6. At that time, the wall 5 is built up so as to balance the forces among the weight of the structure B, the amounts of the asphalt 4 and the water 7, and the earth pressure of the buried soil A1.

(Iii) When the wall 5 and the foundation portion B1 such as the foundation board 1 in which the horizontal seismic isolation device 2, the asphalt 4 and the water 7 are interposed in the space are completed, as shown in FIG. B1
The upper part of the structure B2 is constructed in the upward direction. At that time, the work should be performed carefully so that an unbalanced load is not applied to the wall 5.

(Iv) Finally, as shown in FIG. 1, the structure upper part B2
When the structure B is completed, 90 to 95% of the weight of the structure B is supported by the buoyancy of the asphalt 4 and the water 7, and the remaining 5 to 10% of the weight is supported by the horizontal seismic isolation devices 2, 2 ,. Will be.

The structure B constructed as described above has a seismic isolation effect against an earthquake. That is, this seismic isolation effect is based on the following principle.

As described above, the structure B is cut off from the ground A by the asphalt 4, the water 7, and the horizontal seismic isolation devices 2, 2, ..., and is suspended on the two types of fluid materials. Has become. Therefore, the natural period of structure B is
Even if the seismic wave largely deviates from that of the seismic wave, and even if an earthquake occurs and the seismic wave reaches the ground A near the structure B, a slight seismic wave is input to the structure B. Further, the energy returned from the structure B is also dissipated by the asphalt 4 and the water 7.

Therefore, the structure B has a seismic isolation function as well as a seismic isolation function.

In this case, the asphalt 4 is used for a horizontal seismic isolation device having a mechanical structure having a problem of durability and reliability, that is, a device having defects such as corrosion, bacterial rot, deterioration due to aging and high stress. It not only solves the problem but also protects it.

Also, as can be seen from Pascal's law, since the seismic isolation structure is a stress boundary except for the position of the horizontal seismic isolation device, the problem of differential settlement can be solved.

Here, a weak point of the structure B having such a floating structure is that it is unstable with respect to a large lateral load generated by a typhoon or the like. Therefore, the amount of the water 7 can be adjusted by a pump (not shown) to freely adjust the height of the water surface. The supporting load that the horizontal seismic isolation devices 2, 2, ... By doing so, for example, when the structure B receives a large wind load due to a typhoon or the like, the pump 7 is used to discharge the water 7, and the water surface is temporarily lowered to reduce the buoyancy by the water. , The horizontal seismic isolation device 2, 2, ...
I will bring it close to 100% of the vertical load. Therefore,
The structure B has increased stability and can sufficiently cope with a large wind load and the like.

From the above, the structure B can be structurally designed under extremely mild design conditions against earthquakes, etc., which reduces the construction cost and enables the rigid structure design of high-rise buildings to be carried out. Can be improved.

In the above implementation, it was considered that the ground was relatively good. However, even if the ground is soft and in bad condition, the problem can be solved by driving the pile directly below the horizontal seismic isolation device. At this time, it is sufficient for the above-mentioned pile design to withstand 5 to 10% of the vertical load as a long-term load and 100% of the vertical load as a short-term load.

In addition, in the above-described embodiment, the asphalt 4 and the water 7 are 2
Although one kind of fluid material may be used alone as the fluid material, bentonite liquid, fluid oil or the like may be used as the fluid material in addition to the asphalt 4 and water 7.

〔The invention's effect〕

As described above, according to the present invention, the horizontal seismic isolation device and the fluid material are interposed between the foundation board and the building, and basically 5% to 10% of the vertical load of the building is horizontally isolated. For seismic devices,
Since it has a seismic isolation structure in which 90 to 95% is charged to the fluid material, the following effects can be obtained.

(I) A defect having a mechanical seismic isolation device, for example, deterioration due to secular change or high stress state, is eliminated, and a seismic isolation structure is provided in which almost no seismic force is input during an earthquake.

(Ii) In addition to the seismic isolation structure, the fluid material also functions as a viscous flow damper, so it is also a vibration control structure.

(Iii) The material used as the fluid material does not change even after a long time, and also serves to protect the horizontal seismic isolation device.

(Iv) Other than the position of the horizontal seismic isolation device, as can be seen from Pascal's law, since it is a stress boundary, the problem of differential settlement does not occur.

Further, in the present invention, since the weight of the structure is divided and supported by the horizontal seismic isolation device and the fluid material that gives the structure a buoyancy in the range of 90 to 95%, the horizontal seismic isolation device is used. The load on the directional seismic isolation device can be made sufficiently small, so that the drawbacks of the so-called mechanical seismic isolation device of the horizontal seismic isolation device, such as deterioration over time and deterioration due to high stress conditions, can be avoided. Can be effectively resolved.

Moreover, since the fluid material supply / discharge means capable of adjusting the fluid surface height of the fluid material is provided, by increasing or decreasing the fluid surface height of the fluid material, the buoyancy acting on the structure increases or decreases,
As a result, the supporting load that the horizontal seismic isolation device bears increases or decreases. Therefore, if a large lateral load is applied to the structure due to a typhoon (in such a case, it will be unstable because it is suspended in the structure or the fluid material to some extent), the liquid level of the fluid material will be lowered. By lowering the buoyancy, the load that the horizontal seismic isolation device bears is brought close to 100%, and thus the structure can sufficiently withstand a large lateral load.

On the other hand, in normal times, the liquid level is raised again and most of the load of the structure is supported by the fluid material, resulting in a seismic isolation structure in which seismic force is not input.

That is, in the present invention, it is possible to simultaneously solve the drawbacks of the horizontal seismic isolation device, which is a mechanical seismic isolation structure, and the disadvantages of the floating seismic isolation structure using a fluid material, and to effectively display only the advantages. It has the unique effect of being able to do it.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention, FIG. 1 is a partial sectional front view showing the whole of the present invention, and FIGS. 2 to 4 are constructions of this embodiment. It is explanatory drawing for demonstrating a procedure. A: Ground, B: Structure, 1 ... Foundation, 2 ... Horizontal seismic isolation device, 4 ... Asphalt (fluid material), 5 ...
Wall, 7 ... Water (fluid material).

Claims (3)

[Claims] 1. A base plate is provided in the ground and a wall is provided upright around the base plate so as to surround the base plate, and these are provided inside the wall and above the base plate. A structure is disposed so that a space is formed between the base plate and the structure, and a horizontal seismic isolation device that supports the structure from the base plate is disposed between the structure and the base plate. In the space portion, a fluid material supporting 90% to 95% of the weight of the structure by buoyancy is interposed, and fluid material supply / discharge means capable of adjusting the liquid level of the fluid material is provided. A characteristic floating seismic isolation structure. 2. The floating seismic isolation structure according to claim 1, wherein the fluid material is asphalt, water, bentonite liquid, or oil. 3. A fluid material of a different type having a specific gravity smaller than that of the fluid material interposed in the space portion between the structure and the foundation board in the space portion between the structure and the wall. The floating seismic isolation structure according to claim 1, characterized in that the floating seismic isolation structure is floated on top of and filled.