JPH0444673B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a seismic isolation structure in which laminated rubber is provided between a foundation and an upper structure.

``Conventional technology'' Seismic isolation buildings have been known in the past, in which laminated rubber is provided between the foundation and superstructure of the building.
Figure 4 shows the schematic structure of such a seismic isolation building. In the building shown in FIG. 4, laminated rubber 3 for supporting the upper structure 2 is provided between the foundation 1 and the upper structure 2, thereby lengthening the natural vibration period of the upper structure 2. from the foundation 1 to the upper structure 2
It is designed to reduce the seismic force transmitted to the area, thereby suppressing its vibrations. Numbers 4 and 5 in the diagram
are the footings and piles that make up the foundation part 1, and 6 are the columns that make up the upper structure;
7 is the floor slab of the lowest floor, and 8 is its floor beam.

By the way, when it becomes necessary to install a water tank such as a heat storage water tank in a seismically isolated building as described above, conventionally, the footing 4 is generally installed as shown in Fig. 4.
It has been considered to install the water tank 9 on the foundation 1 by lowering the position of the water tank 9 from the normal position and digging between them.

``Problem to be solved by the invention'' However, as mentioned above, the water tank 9 in the foundation part 1
If this is done, the amount of root cutting will increase, which will increase construction costs. In addition, in the above-mentioned base-isolated building, the foundation 1 and the upper structure 2 vibrate separately during an earthquake, and the amount of displacement of the upper structure 2 becomes large. Equipment piping, etc. installed across the space must be able to accommodate sufficient displacement differences, and for this reason, countermeasures such as the use of a large number of flexible joints, etc., have been necessary.

This invention was made in view of the above circumstances,
The purpose of this is to solve the above-mentioned problems that occur when installing a water tank such as a heat storage tank in a seismic isolation structure using laminated rubber, and in addition,
An object of the present invention is to provide a seismic isolation structure that can effectively damp vibrations of an upper structure.

"Means for Solving the Problems" The present invention provides a seismic isolation structure configured to suppress vibrations of the upper structure by providing laminated rubber between the foundation and the upper structure. A water tank such as a heat storage tank is installed at a predetermined position of the upper structure, and approximately 1/50 of the mass of the upper structure is placed in the water tank.
It is characterized by storing a liquid having a mass of ~1/100.

"Function" In this invention, since the water tank is provided to the upper structure, the amount of root cutting does not increase, and
There is no need to take measures against displacement of equipment piping, etc.

Further, in this invention, not only the vibration of the upper structure is suppressed by the laminated rubber, but also the liquid stored in the water tank has the same vibration period as the upper structure and with a predetermined phase difference. By generating vibrations (sloshing), vibrations of the upper structure are effectively damped.

"Embodiment" An embodiment of the present invention will be described below in Figures 1 to 3.
This will be explained with reference to the figures. Fig. 1 is a sectional view showing the schematic structure of the seismic isolation building of this example.
The same parts as those of the conventional building shown in the figure are given the same reference numerals.

The building of this embodiment is a medium-low-rise building, and a bottom plate 1 is placed between the lower ends of the floor beams 8 on the lowest floor.
0, a water tank 11 is installed under the floor. This water tank 11 is used as a heat storage water tank, and water 12 in an amount of about 1/50 to 1/100 of the weight of the upper structure 2 is stored therein. As a result, the water 12 in the water tank 11
When the upper structure 2 vibrates due to an earthquake or wind, it vibrates (sloshing) at the same period as the upper structure 2 and with a predetermined phase difference.

It is desirable that the water tank 11 is provided in the center of the building in plan view. For example, buildings are the second
As shown in the figure, in the case of a planar shape of 3 spans x 4 spans, there is one water tank for two spans in the center.
It is good to provide 1.

In the above building, since the water tank 11 is installed on the upper structure 2, the position of the footing 4 can be lowered as in the conventional case where it is installed on the foundation 1.
There is no need to cut down the roots to install the water tank, so construction costs do not increase. Moreover,
By simply providing the bottom plate 10 between the lower ends of the floor beams 8,
The water tank 11 can be installed by effectively utilizing the space under the floor, which was conventionally a dead space. In addition, in this case, the equipment piping does not span the upper structure 2 and the foundation 1, so
There is no need to take measures to cope with large displacements as in the conventional case, and it is sufficient to simply fix the structure to the upper structure 2.

In addition, in this building, the superstructure 2
When the water 12 in the water tank 11 vibrates due to an earthquake or wind, the water 12 in the water tank 11 has the same period as the upper structure 2,
and vibration with a predetermined phase difference (slotzing)
Therefore, vibration energy is absorbed and vibrations of the upper structure 2 can be effectively damped. That is, in the building of this embodiment, the vibration suppressing effect due to the laminated rubber 3 and the vibration damping effect due to the sloshing of the water 12 in the water tank 11 can be obtained at the same time.

It should be noted that it has already been proposed to dampen the vibrations of buildings by using sloshing of liquid stored in a water tank (for example, Japanese Patent Application Laid-open No. 101764/1983).
Conventionally, such a method was only applied to skyscrapers whose natural vibration periods naturally become longer. When applied to a skyscraper, conventional methods have the following drawbacks, but these drawbacks have been eliminated in the buildings of the above embodiments.

In other words, in order to effectively obtain the vibration damping effect of sloshing, the mass of the water relative to the mass of the structure must be adjusted so that the vibration period of the water in the tank is the same as the natural vibration period of the structure. However, in the case of conventional skyscrapers, the natural vibration period is determined by the structure of the building itself, so by storing an amount of water corresponding to the mass of the structure, the vibration period of the water can be adjusted to match the vibration period of the structure. It was not always easy to match the natural vibration period. On the other hand, in the building of this embodiment, the natural vibration period of the upper structure 2 can be freely set by the laminated rubber 3, so that the vibration period of the water 12 in the water tank 11 can be adjusted freely by the upper structure 2. It is extremely easy to set the amount of water to match the natural vibration period of the body 2, and as a result, it is possible to obtain a sufficient vibration damping effect with certainty.

In addition, typical skyscrapers exhibit a vibration mode whose amplitude increases as you approach the upper floors.
The installation location of the water tank was limited to upper floors (particularly on the rooftop where the amplitude is maximum). On the other hand, in the building of this example, since it is a medium-low-rise building using seismic isolation rubber 3, its vibration mode is the 3rd vibration mode.
As shown in the figure, the entire upper structure 2 moves in translation like a rigid body, and the amplitudes of the upper and lower floors are approximately equal. Therefore, in this case, tank 1
The location of equipment No. 1 is not limited to the upper floors;
Even if it is provided at any position of the upper structure 2, a sufficient vibration damping effect can be obtained. Therefore, it becomes possible to effectively utilize the space under the lowest floor, which was previously a dead space.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the above embodiment, the water tank is used as a heat storage water tank, but it is of course possible to use it as a drinking water tank or a firefighting water tank, or the main purpose is to obtain a vibration damping effect. It can also be used as a water tank. Furthermore, the liquid stored in the water tank is not limited to water.

In addition, in the above embodiment, the water tank was installed under the floor of the lowest floor to make effective use of the dead space.
This is not necessarily the case, and as mentioned above, it may be provided at any position on the upper structure. Also, if the installation position of the water tank is set at the center of the building in plan,
Although there is an advantage that the vibration damping effect has no directionality and torsional vibration of the upper structure can be effectively prevented, this may not necessarily be the case depending on the planar shape of the building.

Furthermore, the present invention is applicable not only to buildings such as buildings, but also to various seismic isolation structures using laminated rubber.

"Effects of the Invention" As explained in detail above, the present invention provides a water tank such as a heat storage water tank installed at a predetermined position of the upper structure of a seismic isolation structure using laminated rubber, and in the water tank,
Because it stores liquid with a mass that is approximately 1/50 to 1/100 of the mass of the upper structure, there is no need to increase the amount of cuttings that would be required in the conventional case of installing a water tank in the foundation. , there is no need to take measures against the displacement of equipment piping, and in addition to the vibration suppressing effect of the laminated rubber, the vibration of the upper structure can be effectively damped by the sloshing of the liquid in the water tank. Extremely effective.

[Brief explanation of drawings]

Figures 1 to 3 show an embodiment of the present invention. Figure 1 is a sectional view showing the schematic structure of a building according to this embodiment, and Figure 2 is an example of the planar shape of this building. The plan view shown in FIG. 3 is a diagram showing the vibration modes of this building. FIG. 4 is a cross-sectional view showing a schematic configuration when a water tank is installed in a conventional seismically isolated building. DESCRIPTION OF SYMBOLS 1... Foundation part, 2... Upper structure, 3... Laminated rubber, 11... Water tank, 12... Water (liquid).

Claims (1)

[Claims] 1. In a seismic isolation structure configured to suppress vibration of the upper structure by providing laminated rubber between the foundation and the upper structure, a water tank such as a heat storage water tank is installed at a predetermined position of the upper structure. Approximately 1/50 to 1/100 of the mass of the upper structure is installed in the water tank.
A seismic isolation structure characterized by storing a liquid having a mass of .