JPS6389751A - Earthquake damping support apparatus - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a seismic isolation support device for a nuclear reactor building, reactor related equipment, other important structures, etc.

<Prior Art and its Problems> If an important structure such as a nuclear reactor is destroyed by an earthquake, it may cause a serious disaster, so it has been proposed to have a seismic isolation structure including the building.

The base isolation structure focuses on the fact that the peak frequency of earthquakes is 5 to 10 Hz, and by setting the natural frequency of the ff1ffi object supported by a spring to 1) 1z or less, the vibration transmitted from the ground to the heavy object is reduced by the spring. The aim is to absorb and block it.

One such spring device for seismic isolation is a laminated seismic isolation rubber. As shown in Fig. 3, the laminated seismic rubber is made by stacking thin rubber plates and steel plates C alternately between two upper and lower steel plates a and a and bonding them together. Due to the elastodynamic properties of rubber, such laminated anti-seismic rubber is stiff and has a large spring constant against loads in the vertical direction, and is soft and has a small spring constant against loads in the horizontal direction. and the horizontal resiliency constant can be as high as 1000 times. When such a laminated seismic isolation rubber is used as a support device, there is a problem in that although seismic isolation in the horizontal direction can be obtained, seismic isolation in the vertical direction cannot be obtained.

On the other hand, one type of spring device is an air spring as shown in FIG. As shown in the figure, it has a structure in which a rubber membrane f with a U-shaped cross section is provided between a metal cylinder (outer cylinder) d and a piston (inner cylinder) e. Deformation causes overall expansion and contraction. The cylinder and piston move relative to each other in response to a change in external force in the vertical direction, causing the internal volume to change, which changes the pressure and counteracts the external force. It is designed to be balanced.

In response to an external force in the horizontal direction, as shown in Figure 5, when the rubber gf is displaced by δ in the horizontal direction, the 0 character of the rubber gf on the pressed side hangs downward, the pressure receiving area in the horizontal direction increases, and the opposite On the other hand, since the pressure-receiving area decreases on the side, a difference in the pressure-receiving area occurs, and this difference is approximately proportional to the displacement δ, so a restoring force 9 proportional to the displacement δ acts.

When such an air spring is used as a seismic isolation support device, seismic isolation in the vertical and horizontal directions can be obtained, but it is difficult to obtain a sufficient permissible stroke in the horizontal direction due to the strength of the rubber membrane.
The problem is that it cannot withstand large earthquakes.

<Object of the Invention> The present invention was devised in view of the problems of the prior art, and provides a seismic isolation support device that skillfully combines laminated seismic insulation rubber and air springs to have sufficient seismic isolation function in both vertical and horizontal directions. The purpose is to provide

<Means for Solving the Problems> In order to achieve the above object, the seismic isolation support device of the present invention includes an outer cylinder, an inner cylinder, and a diaphragm that connects the two cylinders to form a sealed space between the two cylinders. It is characterized by comprising an air spring and a laminated seismic insulation rubber stacked and fixed under or above the air spring.

Practical example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of the seismic isolation support device of the present invention, and FIG. 2 is a side view showing the case where the seismic isolation support device of the present invention is used in a nuclear reactor building.

In Figures 1 and 2, 1 is an air spring, 2 is a laminated seismic rubber, 3 is an outer cylinder, 4 is a diaphragm, 5 is an inner cylinder, 6
is a rubber stopper, 7 is inner cylinder rubber, 8 is outer cylinder rubber, 9
1 is a dew-proof rubber, 10 is an annular steel plate, 11 is a lower steel plate, 2
0 is a seismic isolation support device, and 21 is a reactor building.

As shown in the figure, the air spring 1 has a structure in which a diaphragm 4 is provided between an outer cylinder 3 and an inner cylinder 5.
have a structure in which cylinders 3b and 5b are concentrically welded to disks 3a and 5a, respectively, and the space between the outer cylinder 2 and the inner cylinder 5 is sealed by a diaphragm and filled with pressurized air. There is.

A cylindrical rubber stopper 6 is fixed to the upper surface of the inner cylinder, and supports the outer cylinder 3 by coming into contact with the lower surface of the disk 3a of the outer cylinder when air is handled. An outer cylinder rubber 8 and an inner cylinder rubber 7 are fixed to the inner surface of the outer cylinder 3b and the outer surface of the inner cylinder 5b, respectively, to protect the diaphragm 4. A laminated seismic insulation rubber 2 is fixed to the lower surface of the cylindrical disk 5a, and a lower steel plate 11 is fixed to the lower end of the laminated seismic insulation rubber.

If the laminated seismic rubber 2 is a solid cylinder, the diameter will be too small if the required spring constant is used, and there is a risk of buckling, so a hollow cylinder as shown in the figure is used.

As shown in the figure, the laminated earthquake-proof rubber 2 has a structure in which a large number of annular steel plates 10 are embedded and bonded to a cylindrical dew-proof rubber 9.

In this example, the air spring 1 is stacked on the laminated seismic insulation rubber 2, but the laminated seismic insulation rubber 2 may be stacked on the air spring 1 conversely. In addition, in this example, the dew-proof rubber also serves as the legs of the inner cylinder of the air spring, so the overall height is lower and more compact.

In addition, the laminated seismic rubber 2 has a large rubber thickness between the steel plates 10,
If the spring constant in the vertical direction is small, the load will be large, which may cause creep, which is undesirable. Usually, the ratio of the spring constants in the vertical direction and the horizontal direction is 100 to 1000 times.

Next, the action will be explained.

Considering the case where an earthquake occurs while a building 21 or the like is supported by such a seismic isolation support device 20 as shown in FIG. The air is transmitted to the inner cylinder 5 of the spring, but is blocked by the air spring 1, so it is not transmitted to the building. In addition, vibrations in the horizontal direction are absorbed by the laminated antiseptic rubber 2 and the air spring 1, and the permissible displacement of the laminated antiseptic rubber 2 is large, so even if the lateral amplitude of an earthquake exceeds the allowable stroke of the air spring 1, the vibration will not occur. is not transmitted to the building.

The experimental results of the seismic isolation support device of the present invention are shown in Fig. 6 below.
This will be explained with reference to FIG. In the experiment, the four corners of a square concrete block of approximately 24 tons were supported by the seismic isolation support device of the present invention on a raised device, and the vibration state of the concrete block was recorded by applying horizontal vibration and vertical photography. Figure 6 shows the horizontal direction, and Figure 7 shows the vertical direction. In both figures 6 and 7, the horizontal axis shows the frequency (1, tZ),
The vertical axis shows the amplitude magnification. In FIG. 6, beak A is lateral vibration, and beak B is rocking mode vibration. As is clear from Figures 6 and 7, there is almost complete seismic isolation at earthquake peak frequencies of 5 to 10 seismic frequencies.

<Effects of the Invention> As described above, the seismic isolation support device of the present invention has the following effects.

(1) Since it uses a combination of laminated antiseptic rubber and air springs, it has a seismic isolation effect against vertical and horizontal vibrations. It can also handle larger horizontal vibrations than when only air springs are used.

■ If a defective support device needs to be replaced, it can be easily replaced by removing the air from the air spring of that device, which is advantageous in terms of maintenance compared to using only laminated seismic rubber.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the seismic isolation support device of the present invention, Fig. 2 is a side view showing the case where the seismic isolation support device of the present invention is used in a nuclear reactor building, and Fig. 3 is a side view of laminated antiseptic rubber. Figure 4 is a cross-sectional view of the air spring, Figure 5 is a cross-sectional view explaining the mechanism by which restoring force is generated when a horizontal load is applied to the air spring, and Figure 6 is the amplitude of vibration in the horizontal direction. FIG. 7 is a drawing showing changes in amplitude with respect to vibration in the vertical direction. 1... Air spring 2... Laminated antiseptic rubber 3... Outer cylinder 4... Diaphragm 5... Inner cylinder Fig. 1 Fig. 2 Figure 3 h Factor 4 Figure 5 Width Figure 6 Magnification

Claims (1)

[Claims] An air spring consisting of an outer cylinder, an inner cylinder, and a diaphragm that connects the two cylinders to form a sealed space between the two cylinders, and a laminated earthquake-proofing rubber stacked and fixed under or above the air spring. A seismic isolation support device characterized by: