JPH03288038A - Variable characteristic earthquake-isolating device and variable characteristic earthquake-isolating system - Google Patents

Abstract

PURPOSE:To effectively control vibration of buildings, etc. in response to the types of disturbances, their vibration levels, vibration characteristics, etc. by actively controlling elastic supports providing earthquake-isolating construction in such conditions where the elastic supports are separated from the superstructure or the foundation part, the supports are weakly pressed against the superstructure or the foundation, the supports are strongly pressed against the superstructure or the foundation, etc. CONSTITUTION:Between the foundation part 4 and the superstructure 5, an earthquake-isolating device such as a laminated rubber 8, etc. used for normal earthquake-isolating construction, and a variable characteristic earthquake- isolating device 1 provided with a drive device 3 which vertically expands and contracts, such as actuator, etc. provided under a laminated rubber 2, are installed. Then disturbances such as earthquake, wind, etc. detected by sensors 9, 10 installed on the foundation part 4 side or the ground and on the superstructure 5 side are analyzed by a control device 11 so as to operate the drive device 3 of the variable characteristic earthquake-isolating device 1.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a variable characteristic seismic isolation device and a variable characteristic seismic isolation system using the device. Compared to seismic structures, this structure has higher seismic safety, improved livability during small to medium earthquakes and strong winds, and improved protection performance.

[Conventional technology]

Conventional technology includes a normal seismic isolation structure. That is,
By using seismic isolation bearings such as laminated rubber, the natural period of the building can be extended and the resonance phenomenon caused by the coincidence of the predominant period of seismic motion and the natural period can be avoided, thereby reducing the seismic force acting on the building. By absorbing vibration energy with the damping device, we aim to further reduce seismic force and suppress response displacement.

[Problem to be solved by the invention]

However, conventional seismic isolation structures are passive restraining structures whose characteristics are predetermined, resulting in the following problems.

■ Normally, the natural period is set to 1 to 3 seconds, and depending on the nature of the seismic motion, resonance phenomena may occur.

■ Normally, in order to suppress shaking caused by strong winds, the stiffness is set to be high using the elastic stiffness of elastoplastic dampers when the amplitude is small, but this has the effect of impairing the seismic isolation effect in small and medium earthquakes.

■ Also, high rigidity at small amplitudes may impair vibration isolation performance for blocking minute vibrations such as traffic vibrations.

■ Many of the damping devices currently in practical use have amplitude dependence on their damping performance, so it is difficult to always achieve ideal performance.

As a means to solve these problems, it is sufficient to appropriately change the period and damping properties of the seismic isolation structure from time to time depending on external disturbances and the response of the building. The variable characteristic seismic isolation system of the present invention aims to realize this.

[Means to solve the problem]

The variable characteristic seismic isolation device of the present invention is configured such that an elastic bearing used in conventional seismic isolation structures, such as laminated rubber, can be moved in the vertical direction by a driving means using an actuator or an electric motor. . This device is interposed between the superstructure and the foundation of a building or heavy equipment, and is usually attached to the foundation, and by operating the drive means, it can separate the elastic bearing from the superstructure. It can be pressed against the superstructure with a predetermined pressure. Note that, in principle, it is also possible to configure the device to be attached to the upper structure side and pressed against the base portion side.

The variable characteristic seismic isolation system of the present invention incorporates the variable characteristic seismic isolation device described above, and is constructed by using the variable characteristic seismic isolation device together with a plurality of elastic bearings in a conventional seismic isolation structure. In addition, similar to conventional seismic isolation structures, elastoplastic dampers and the like can also be used together.

In order to suppress the vibration of a building using the variable characteristic seismic isolation system of the present invention, various disturbances detected by sensors placed in the building, the ground, etc. are analyzed by a control means using a computer or an electric circuit, etc. Depending on the level and response of the building, a command signal is given to the drive section of the variable characteristic device.

〔Example〕

Next, the present invention will be explained based on the drawings.

FIGS. 1(a) and 1(b) show a variable characteristic seismic isolation device 1 of the present invention.
This schematically shows a drive device 3 such as an actuator that expands and contracts vertically under the laminated rubber 2, and this is installed on the side of the base 4.

When the drive device 3 is retracted as shown in FIG. 1(a), the upper structure 5 of the building etc. and the laminated rubber 2 are separated from each other. )
The laminated rubber 2 is pressed against the upper structure 5 as shown in FIG. Friction plates 6.7 are attached to the contact surfaces of the laminated rubber 2 and the upper structure 5, respectively.

The laminated rubber 2 attached to the drive device 3 is made to be somewhat soft, so that it does not have the same rigidity in the horizontal direction as a mid- to low-rise building, and in the vertical direction, the aim is to eliminate slight vibrations and simplify driving. The reason why it was decided to press it in the vertical direction is that since the structure originally has a displacement of 10 to 20 cm in the horizontal direction, it is difficult to design the device, and the response may be adversely affected during driving.

FIG. 2 shows an outline of the variable characteristic seismic isolation system of the present invention, in which a seismic isolation device such as laminated rubber 8 in a normal seismic isolation structure is installed between the foundation 4 and the superstructure 5, and the variable characteristics seismic isolation system described above is A characteristic seismic isolation device 1 is installed, and the control device 11 analyzes disturbances such as earthquakes or wind detected by sensors 9 and 10 installed on the foundation 4 side or the ground and superstructure 5 side, and the variable characteristic device 1 is installed. The drive device 3 of is activated.

FIGS. 3(a) to 3(C) show changes in the horizontal characteristics of the seismic isolation layer due to the variable characteristic seismic isolation device 1. That is, the operation of the drive device 3 enables three types of changes in horizontal characteristics as shown in the figure. At the time of separation, as shown in FIG. 3(a), only the normal laminated rubber 8 is in its softest state. If it is pressed weakly, as shown in Figure 3(b), when the horizontal force exceeds the frictional force, sliding will occur and a large energy absorption and damping effect can be expected. Also, if you press it too hard,
As shown in FIG. 3(C), no sliding occurs and the state is the hardest.

Furthermore, by installing a plurality of variable characteristic devices 1 and controlling them separately, various characteristics can be obtained, and it is possible to select the optimum stiffness and damping properties from time to time in order to suppress the response of the upper building as much as possible. can. As the simplest example, as shown in Figure 4, if an earthquake occurs that causes a certain degree of resonance due to the characteristics at a distance, a command is given to the variable characteristic device 1 to determine the response spectrum. It is possible to add stiffness to minimize the response of the valley.

〔Effect of the invention〕

In the present invention, the elastic bearing that provides the seismic isolation structure can be actively controlled between the state in which it is separated from the superstructure or the foundation, the state in which it is weakly pressed, and the state in which it is strongly pressed. Vibrations of buildings, etc. can be effectively controlled according to vibration levels, vibration characteristics, etc. In addition, when the elastic bearing is pressed against the upper structure or the foundation, energy absorption and damping effects can be expected in relation to the pressing force, such as by using a friction plate on the contact surface, and it is possible to It is also possible to have the function of an elastoplastic damper in an earthquake structure.

[Brief explanation of drawings]

Figures 1 (a) and (b) are schematic diagrams of the variable characteristic seismic isolation device of the present invention, Figure 2 is a schematic diagram of the variable characteristic seismic isolation system of the present invention, and Figures 3 (a) to (C) are A graph showing changes in the horizontal characteristics of the seismic isolation layer due to the variable characteristic seismic isolation device, and FIG. 4 is a graph showing the relationship between the acceleration response spectrum of seismic motion and control. 1... Variable characteristic seismic isolation device, 2... Laminated rubber, 3...
- Drive device, 4... Foundation part, 5... Upper structure, 6.
7-...Friction plate, 8...Laminated rubber, 9, 10...Sensor, 11...Control device Fig. 1 (a) (b) Fig. 3 at w) (C) Fig. 4 Figure 2: General low- and medium-rise buildings, seismic isolation, and super high-rise buildings

Claims (5)

[Claims] (1) Consisting of an elastic bearing having a predetermined rigidity in the horizontal and vertical directions, and a driving means for driving the elastic bearing in the vertical direction, the driving means is attached to one of the upper structure and the base, and the driving means is attached to the other. A variable characteristic seismic isolation device characterized in that the elastic bearing can be pressed with a predetermined pressure. (2) The variable characteristic seismic isolation device according to claim 1, wherein the elastic bearing is made of laminated rubber. (3) Claim 1 or 2, wherein a friction plate is provided on the contact surface of the elastic bearing with the upper structure or the base when it is pressed.
Variable characteristic seismic isolation device as described. (4) A variable characteristic seismic isolation device characterized in that, together with the variable characteristic seismic isolation device according to claim 1, 2 or 3, a plurality of elastic bearings constituting a seismic isolation layer are provided between the upper structure and the foundation. system. (5) A variable characteristic seismic isolation system further comprising a damper between the superstructure and the foundation.