JPH04111810A - Underwater earthquake-isolating method and structure - Google Patents

Abstract

PURPOSE:To reduce the cost of construction by a method in which a building having an earthquake isolator on its downside is put in water and loads to the earthquake isolator are relieved by the buoyancy of the building. CONSTITUTION:The ground G where atomic power facilities are to be constructed is excavated, reinforcing bars are assembled, and concrete is placed to form a base slab 10b. A formwork for a retaining wall 10a is constructed, reinforcing bars are assembled, and concrete is placed to form a retaining wall 10a. The donwside of earthquake isolators 11 is fixed to the pedestal 10c provided on the slab 10b, and a building 20 is constructed on the isolators 11 and water is supplied into the space between the building 20 and the bottomed box body 10 to construct an underwater earthquake-isolating structure A.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an underwater seismic isolation construction method and an underwater seismic isolation structure used when a building is provided with a seismic isolation device that absorbs vibrations caused by earthquakes, etc. It is something.

[Prior Art] In recent years, seismic isolation structural systems have been increasingly used in office buildings, condominiums, and the like. As is generally well known, these seismic isolation structural systems use laminated rubber with very low horizontal stiffness to extend the building's natural period and prevent large accelerations from being transmitted to the building. Furthermore, by combining the above laminated combs with seismic isolation devices such as viscous dampers, steel tampers, lead tambours, or friction dampers, the building's acceleration response is reduced from small to large earthquakes. There is. Also,
Some use high-attenuation laminated combs that have attenuation performance in the laminated combs themselves.

A seismic isolation structure using such a seismic isolation device has a structure in which the seismic isolation device 1 is simply provided on the side surface of the building or on the bottom surface as shown in FIG. Reference numeral 2 is the building, and reference numeral 3 is the ground.

[Problems to be Solved by the Invention] However, since conventional seismic isolation devices are very expensive, there is a problem in that installing a seismic isolation device in a building structure requires high construction costs.

The present invention has been made in view of such problems, and its object is to provide an underwater base isolation method and an underwater base isolation structure that can reduce construction costs compared to conventional techniques. be.

[Means for Solving Problem 1] The gist of the invention according to claim 1 is to immerse a building provided with a seismic isolation device on the lower surface into water, and to reduce the load applied to the seismic isolation device due to the buoyancy generated in the building. This is due to the underwater seismic isolation construction method that reduces the

The gist of the invention according to claim 2 is to provide a bottomed box-like body having an opening on the top surface, a building housed in the bottomed box-like body, and a lower surface of the building and a bottom upper surface of the bottomed box-like body. The underwater seismic isolation structure includes a seismic isolation device provided between the building and the box-shaped body, and water existing in the gap between the building and the box-shaped body.

1 Effect] Water causes buoyancy in the building, and the buoyancy reduces the load applied to the seismic isolation device. Therefore, the number of seismic isolation devices installed in the building can be reduced.

Therefore, the present invention can reduce the construction cost of a building structure provided with a seismic isolation device.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this example are not intended to limit the scope of this invention to only those, unless specifically stated. It's just an illustrative example.

The underwater seismic isolation structure according to this embodiment will be explained using FIG. 1.

The underwater seismic isolation structure A is applied to a nuclear power plant as shown in Fig. 1, and consists of a box-like body 10 with a bottom built in the ground G and a part of the box-like body 10 with a bottom. a building 20 of a nuclear power plant, a plurality of seismic isolation devices 11 provided between the building 20 and the bottomed box-like body 10, and a gap between the building 20 and the box-like body 10. It consists of 30% water.

The bottomed box-like body 10 includes a retaining wall 10a made of reinforced concrete 1 and having a rectangular outer contour in plan view, and a retaining wall 10a made of reinforced concrete.
It consists of a reinforced concrete foundation plate 10b which is continuous with the base plate 10b. The inner dimensions of the retaining wall 10a are those of the building 2.
It is larger than the outer size of 0. The foundation plate Job is a rectangular plate-like body in plan view, and has pedestal locs provided at required locations on its upper surface, and also connects the retaining wall 10 from the periphery.
A is standing up.

The building 20 houses a nuclear power generation device, and its side walls and bottom slab are constructed of watertight concrete.

The seismic isolation device 11 has its −L surface fixed to the lower surface of the building 20, and its lower surface fixed to the pedestal Oc provided on the base plate Job.

The seismic isolation device 11 may be made of laminated rubber, an oil damper, a steel tamper 1, a lead-containing laminated comb, or a combination thereof, which is suitable for carrying out the present invention.

Next, the underwater base isolation construction method of the underwater base isolation structure constructed as shown below will be explained.

First, after cutting the ground G on which the nuclear power generation facility is to be built, reinforcing bars are assembled and concrete is poured to construct the foundation plate 10b.

Next, formwork for the retaining wall 10a is carried out, and after assembling reinforcing bars in the formwork, concrete is poured to complete the retaining wall 10.
Construct a.

Next, the lower surfaces of the plurality of seismic isolation devices 11 are fixed to the pedestal IOc provided on the base plate Ob.

Next, the building 20 is constructed on top of each of the seismic isolation devices 11.

Next, water is poured into the gap between the building 20 and the bottomed box-like body 10.

The underwater seismic isolation structure A can be constructed through the above steps.

Next, the effects of the underwater seismic isolation method and the underwater seismic isolation structure A configured as shown below will be explained.

■ Cost reduction effect of the seismic isolation device 11 The water 30 injected into the gap between the building 20 and the bottomed box-like body 10 creates buoyancy in the building 20, and the buoyancy reduces the vertical load applied to the seismic isolation device 11. Reduce. 1. Therefore, the number of seismic isolation devices 11 to be provided in the building 20 can be reduced.

For example, the outside size is 80m x 80m and the building weight is 200,000.
When seismically isolating a nuclear power plant of 500 tons, the rated load is 500 tons.
400 seismic isolation devices 11 are required. Building 2
When 0 is sunk to a depth of 20 m, a buoyant force of 128,000 t acts on the building 20, so the apparent weight of the building 20 is 72,000 t, and the number of seismic isolation devices 11 is 40.
The number can be reduced from 0 to 144. When converted into the cost of the seismic isolation device 11, the rated load 1 (assuming the price per unit is 10,000 yen) is 1,280,000 yen.
This results in a cost reduction of 0,000 yen.

■ Advantages in terms of disaster prevention Since the outer periphery of the building 20 is surrounded by water 30, no fire prevention measures are required. Furthermore, since it is virtually impossible for humans to approach, it is also effective against man-made disasters such as acts of terrorism.

■ Rationalizing the design of the retaining wall 10a In the case of a building with deep embedding, the design of the retaining wall 10a becomes difficult due to an increase in earth pressure load, or water pressure is applied, so the stress applied to the retaining wall 10a is significantly alleviated. Retaining wall 10
It becomes possible to rationalize the design of a. However, it is possible to reduce the amount of concrete placed, the amount of reinforcement, etc. required to construct the retaining wall 10a, and the construction cost can be reduced.

■ Improving the durability of laminated combs It is known that the deterioration of laminated rubber is affected by oxygen and ozone in the atmosphere. By adopting this construction method, laminated rubber is completely isolated from the atmosphere, so these factors can It becomes possible to significantly suppress deterioration.

In this embodiment, the retaining wall 10a is vertically disposed on the periphery of the base plate 10b, but this is not intended to limit the scope of the present invention, and other configurations,
For example, a method suitable for carrying out the present invention, such as an oblique installation method, can be used.

[Effects of the Invention] The present invention can reduce the construction cost of a building structure provided with a seismic isolation device by reducing the number of seismic isolation devices to be provided in a building.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an underwater seismic isolation structure according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional seismic isolation structure. A...Underwater base isolation structure, 10...Bottomed box-shaped body, 11...Seismic isolation device, 20
Building, 30 ・Water.

Claims (2)

[Claims] (1) An underwater seismic isolation construction method in which a building with a seismic isolation device installed on the lower surface is placed in water, and the buoyancy generated in the building reduces the load applied to the seismic isolation device. (2) A bottomed box-like body having an opening on the top surface, a building enclosed in the bottomed box-like body, and a building provided between the lower surface of the building and the bottom upper surface of the bottomed box-like body. An underwater seismic isolation structure comprising a seismic isolation device and water existing in a gap between the building and the box-shaped body.