JP2001003982A - Non-resonant semi-active base isolating structure and base isolating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a base isolating layer to efficiently exhibit its base-isolating effect by preventing resonance through simple control even in the event of long-term earthquake motions, and reducing energy. SOLUTION: A rigidity changeover device 4 is provided in parallel with a base isolating device 3 which forms a base isolating layer between a support part 1 and an upper structure 2. Based on earthquake motions detected by a sensor 5 installed on the support structure part 1, a control device 6 calculates in real-time the expected response of the upper structure 2 and indicates the rigidity changeover device 4 to switch to the rigidity at which resonance will not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a base-isolated building, a base-isolated bridge, and a base-isolated bridge that reduce the response of a superstructure by forming a base-isolated layer that blocks vibration against vibration disturbance such as an earthquake. Non-resonant semi-active seismic isolation structure and non-resonant semi-active seismic isolation method with improved seismic isolation function, such as a floor of a building, by changing the performance of the seismic isolation layer according to the input earthquake motion etc. It is.

[0002]

2. Description of the Related Art Conventional techniques for reducing the response of a structure to vibration disturbances such as earthquakes and winds include what is called a seismic isolation structure or a damping structure.
Conventionally, it is classified as passive damping, which is one of the damping structures.

However, recently, an active seismic isolation structure has been developed in which an active function is added for the purpose of improving the performance of the seismic isolation structure, and the performance of the seismic isolation layer is actively controlled. For example, in Japanese Patent No. 2794418, a variable damping device (a damping force variable damper) is installed in a seismic isolation layer,
A seismic isolation method is described, in which the response characteristics of the variable damping device are continuously and continuously controlled in real time based on information from vibration sensors installed on the support structure (base) and the upper structure (structure). .

[0004]

In the case of a seismic isolation structure, its period is generally longer than that of a normal structure. As a result, the response to the predominant short-period ground motion can be reduced by avoiding resonance.

[0005] However, for long-period ground motions expected in soft ground or sedimentary plains, resonance cannot be avoided and the response increases, and the response of the structure and the deformation of the seismic isolation layer fall within the allowable values. There were cases where it was difficult to design a safe and reliable structure, for example, because it could not fit.

On the other hand, the above-mentioned Japanese Patent No. 279441 described above.
The active seismic isolation system described in Japanese Patent Publication No. 8 is focused on controlling the damping force generated by the variable damping device and minimizing the response deformation of the seismic isolation layer without deteriorating the seismic isolation effect as much as possible. I have.

In addition, sensors are installed on both the supporting structure and the upper structure, and in the form of feedback control, the optimal damping response output signal for the dominant period of vibration, maximum acceleration, maximum speed, maximum displacement, etc. is calculated in real time. A method such as processing is adopted.

However, the above-mentioned method is different from the concept of reducing the input energy by non-resonance according to the present invention, in that it attempts to absorb the energy of the earthquake input by control using a variable damping device. Since the absorbed energy is absorbed by the device, there is a difficulty in increasing the size of the device.

In order to continuously control the damping force of the variable damping device, if the device is a hydraulic device, it is necessary to precisely adjust the valve opening of the flow control valve, and a controller for this is required. The mechanism of the device and its handling are complicated.

[0010] Therefore, the cost of the apparatus itself is high, and maintenance is also difficult. On the other hand, in the present application, since the device can be basically switched on and off, the mechanism is simplified and the handling is easy. Therefore, it leads to low cost and easy maintenance.

The present invention has been made to solve the above-mentioned problems in the prior art, and it is possible to make a non-resonant state by a simple control even for a long-period seismic motion, etc., to reduce input energy, It is an object of the present invention to provide a non-resonant semi-active seismic isolation structure and a seismic isolation method capable of efficiently exhibiting a seismic isolation effect in a layer.

[0012]

A non-resonant semi-active seismic isolation structure according to claim 1 of the present application is formed by forming a seismic isolation layer with a seismic isolation device interposed between a support structure and an upper structure. In the seismic isolation structure, a rigidity switching device arranged in parallel with the seismic isolation device and having a variable rigidity connecting the support structure and the upper structure, a sensor for detecting seismic motion or vibration of the support structure, and a sensor Based on the input seismic motion or vibration information of the supporting structure, the response of the superstructure to the supporting structure is calculated in real time according to the rigidity of the rigidity switching device, and the resonance is not resonant with the rigidity switching device. And a control device for instructing switching to rigidity.

According to a second aspect, in the non-resonant semi-active seismic isolation structure according to the first aspect, the rigidity switching device can switch between a high rigidity state and a low rigidity state in two or three or more stages. Is limited to the case where

FIG. 10 compares the principle of the conventional active seismic isolation structure with the principle of the non-resonant semi-active seismic isolation structure according to the present invention in the form of a dynamic model. In the conventional active seismic isolation structure shown in (a), the supporting structure and superstructure (mass M)
A variable damping device is arranged in parallel with a seismic isolation device (horizontal spring K) made of laminated rubber etc. for the seismic isolation layer that connects
, Optimal control is performed in such a way that the response of the superstructure becomes as small as possible.

On the other hand, in the non-resonant semi-active seismic isolation structure of the present invention shown in (b), the seismic isolation device (horizontal spring K) is used.
And a rigidity switching device is provided in parallel with the rigidity switching device.
By switching (k ₁ , k ₂ ,...), The natural period of the superstructure with respect to the supporting structure is changed. For example, when a long-period seismic motion is input, the rigidity is increased and the structural system is shortened. Resonance can be avoided and consequently the response of the superstructure can be reduced.

That is, the vibration characteristic of the upper structure with respect to the support structure is determined by the sum of the rigidity K of the seismic isolation layer due to the horizontal spring and the rigidity k of the rigidity switching device. Accordingly, the vibration characteristics of the upper structure with respect to the support structure change, and non-resonance becomes possible.

In the case of the conventional active seismic isolation structure of (a),
In order to achieve the optimal control effect, sensors are usually provided in both the support structure and the upper structure, and control is performed by feedback.However, in the case of the present invention shown in FIG. The input energy is reduced by the resonance, and the feedforward control that switches the stiffness so as to be non-resonant with the input seismic motion is sufficient. Therefore, the sensor is installed on the support structure side.

In addition, it is considered that the rigidity switching device is basically switched on or off in two stages between a high rigidity state and a low rigidity state, or switching the rigidity in several stages is sufficient. Is limited to that case.

As a specific structure of the rigidity switching device, for example, as described in Japanese Patent Application Laid-Open No. Hei 3-186602, the oil-sealed damper can be locked in two stages, ie, in a locked state and in an unlocked state, according to an instruction from a control device. And a variable damping device of which rigidity is variable by adjusting the opening of the valve. Claim 3 limits that case.

Further, the present invention limits the case in which the rigidity switching device comprises a damper in which an ER fluid or an MR fluid is sealed. A structure in which the rigidity between the upper structures is variable can also be used.

In addition, a friction damper type device which can be adjusted in two or more stages can be used. Claim 5 is Claim 1, 2, 3, or 4.
In the non-resonant semi-active seismic isolation structure according to (1), a spring element is connected in series with the rigidity switching device between the support structure and the upper structure.

If the desired rigidity cannot be realized due to the type and mechanism of the rigidity switching device, it is conceivable to adjust the rigidity by interposing a spring element. It is easy to interpose the spring elements in series as in claim 5.

According to a sixth aspect of the present invention, there is provided a non-resonant semi-active seismic isolation method, wherein a seismic isolation device for forming a seismic isolation layer between a support structure and an upper structure, and rigidity for connecting the support structure and the upper structure. A variable rigidity switching device is arranged in parallel, and based on the information of the seismic motion detected by the sensor or the vibration of the supporting structure, the response of the superstructure expected according to the rigidity of the rigidity switching device is performed in real time. And a control device for instructing the rigidity switching device to switch to non-resonant rigidity.

Basically, it is assumed that the rigidity switching device is switched in two or more stages in the form of feedforward based on seismic motion, and the rigidity and vibration characteristics of the upper structure itself and the isolation of the seismic isolation layer are assumed. Since the rigidity (horizontal spring constant) and vibration characteristics of the main body of the vibration device and the vibration characteristics when the rigidity switching device is switched are known in advance, the sensors are stored in a computer or the like as a control device. As soon as the vibration information is input, the stiffness that becomes non-resonant can be selected and an instruction can be sent to the stiffness switching device.

[0025]

FIG. 1 shows an embodiment in which the non-resonant semi-active seismic isolation structure of the present invention is applied to the seismic isolation of a building.

As the seismic isolation structure, a support structure 1 on the foundation side of an ordinary seismic isolation building and an upper structure 2 as a building body are used.
A seismic isolation means 3 such as laminated rubber (usually combined with an elasto-plastic damper or the like) is arranged between them to form a seismic isolation layer.

In the present invention, the rigidity switching device 4 is arranged in such a manner that the support structure 1 and the upper structure 2 are connected in parallel with the seismic isolation means 3, and the vibration detected by the sensor 5 installed on the support structure 1 side. The information is determined by the control device 6 such as a computer, and the rigidity of the rigidity switching device 4 is controlled.

That is, in the general seismic isolation structure, a relatively short period is assumed as the dominant period of the input seismic motion. However, when the dominant period of the input seismic motion is long and the upper structure may resonate, etc. By increasing the rigidity in the rigidity switching device 4 and shifting the natural period of the superstructure to a shorter one, it is possible to reduce the input energy to the superstructure in a form to avoid resonance.

Alternatively, if the rigidity switching device 4 can realize several levels of rigidity, the rigidity of the rigidity switching device 4 can be reduced by reducing the rigidity of the rigidity switching device 4 when there is a possibility that the upper structure will resonate with the input seismic motion. It is possible to shift the natural period of the structure to a longer one.

The seismic isolation means 3 includes, in addition to the ordinary laminated rubber described above, lead-containing laminated rubber, high-damping laminated rubber, sliding bearings, roller bearings, and the like, and in any case, the present invention can be applied. It is.

In the present embodiment, the sensor 5 is installed on the support structure 1 and controlled based on the response of the support structure 1. However, the sensor 5 is installed on a base-isolated building using a communication network. It is also possible to perform control in such a manner as to compensate for mechanical control delay in the rigidity switching device 4 based on information on seismic motion detected by near or near and far seismic sensors.

FIG. 2 shows an embodiment in which the non-resonant semi-active seismic isolation structure of the present invention is applied to a seismic isolation bridge. The basic concept is the same as in the case of the seismic isolation building shown in FIG. 1, in which a laminated rubber bearing as seismic isolation means 3 is provided between the pier as the support structure 1 and the bridge girder as the superstructure 2. Further, a rigidity switching device 4 is provided so as to connect the pier and the bridge girder.

The vibration information from the sensor 5 installed on the top of the pier is judged by the control device 6 and the stiffness of the stiffness switching device 4 is switched so that non-resonance can be achieved irrespective of the input seismic motion.

FIG. 3 shows another embodiment in which the non-resonant semi-active seismic isolation structure of the present invention is applied to the seismic isolation of a building. In this example, a spring element 7 is connected in series with the rigidity switching device 4 in the embodiment of FIG.
This is because, as described above, adjustment is performed when the desired rigidity cannot be achieved depending on the type and mechanism of the rigidity switching device, and the spring element is not particularly limited to rubber, a coil spring made of steel, or the like.

FIG. 4 shows a rigidity switching device 4 used in the present invention.
As an example, an oil-sealed damper-type rigidity switching device is shown. As a configuration, a cylinder 4a having a hydraulic chamber therein is connected to the support structure 1 side via a clevis 8, a piston rod 4b that enters and exits the cylinder 4a is connected to the upper structure 2 side, and the By opening and closing the provided flow switching valve (in the case of two-stage switching) or adjusting the opening degree (in the case of multiple-stage switching), the vibration characteristic of the upper structure 2 can be switched between two or more stages. .

FIG. 5 shows the rigidity switching device 4 used in the present invention.
As another example, a rigidity switching device using a variable friction device is shown. As a configuration, steel friction plates 4c are connected to each other via a frictional force adjuster 4d provided with a servomotor or the like at the center, and the rigidity is made variable by adjusting the joining force by turning on and off. I have.

FIG. 6 shows the rigidity switching device 4 used in the present invention.
5 shows a rigidity switching device in which a spring element 7 is added to the device shown in FIG. In this example, a plurality of rubber plates 7a sandwiched between steel plates 7b are shown as the spring elements 7, but the spring element 7 is not limited to this, and various materials and types can be used. .

FIGS. 7 to 9 show examples of the plane arrangement of the rigidity switching device 4 in the seismic isolation layer, respectively. When arranging a plurality of rigidity switching devices 4, a case where a plurality of devices having the same switching characteristics are arranged and a case where a plurality of devices having different switching characteristics are dispersedly arranged are considered.

FIG. 7 assumes a case in which two-stage switching rigidity switching devices 4A are arranged at four corners in two directions.
FIG. 8 shows a rigidity switching device 4A for two-stage switching, and a rigidity switching device 4 for two-stage switching having a different rigidity from the rigidity switching device 4A.
It is assumed that B is distributed at the four corners and the center.

FIG. 9 assumes a case in which the rigidity switching device 4C having three-stage switching and having a spring element for adjustment is arranged at each of four corners in two directions. The above is merely an exemplary list, and various other combinations are conceivable.

[0041]

According to the present invention, not only the ordinary relatively short-period earthquake input but also the resonance caused by the rather long-period earthquake input, which is the most concerned with the safety of the seismic isolation structure,
By making the resonance of the upper structure non-resonant, the response can be effectively reduced.

Thus, it is possible to reduce the response of the building or the structure itself or the structure such as the base-isolated floor, and to reduce the deformation of the base-isolated layer. In the conventional active seismic isolation, the response was reduced mainly by energy absorption by the damping device, so the load on the device was large, but in the present invention, the energy itself input to the structure can be reduced, The burden on the device is small.

As the rigidity switching device, one having a simple mechanism of ON and OFF is basically sufficient, and the control is simple, so that the control is highly reliable and the maintenance is easy.

The present invention is also applicable to existing seismic isolation structures and floors. The sensors required for the system need only detect seismic motion or vibration of the supporting structure (not required for superstructures).

[Brief description of the drawings]

FIG. 1 is a front view of a base isolation layer according to an embodiment of the present invention.

FIG. 2 is a front view of a seismic isolation layer according to another embodiment of the present invention.

FIG. 3 is a front view of a base isolation layer according to still another embodiment of the present invention.

FIG. 4 is a front view showing an example of a rigidity switching device.

FIG. 5 is a front view showing another example of the rigidity switching device.

FIGS. 6A and 6B show still another example of the rigidity switching device, wherein FIG. 6A is a front view and FIG. 6B is a sectional view taken along line AA.

FIG. 7 is a plan view showing an arrangement example of a rigidity switching device in the seismic isolation layer.

FIG. 8 is a plan view showing another arrangement example of the rigidity switching device in the seismic isolation layer.

FIG. 9 is a plan view showing still another arrangement example of the rigidity switching device in the seismic isolation layer.

FIG. 10 compares the principle of a conventional active control type seismic isolation structure with the principle of the seismic isolation structure of the present invention. FIG. 10 (a) is a mechanical model diagram of the conventional active control type seismic isolation structure. b) is a mechanical model diagram of the non-resonant semi-active seismic isolation structure of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Support structure part, 2 ... Upper structure, 3 ... Seismic isolation means, 4 ... Rigidity switching device, 4a ... Cylinder, 4b ... Piston rod,
4c: friction plate, 4d: friction force adjuster, 5: sensor, 6
... Control device, 7 ... Spring element, 7a ... Rubber plate, 7b ... Steel plate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akihiro Kunisue 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. F-term (reference) 3J048 AA02 AC04 AC05 AD05 BA08 BE03 CB23 EA38

Claims (6)

[Claims] In a seismic isolation structure, a seismic isolation layer is formed by interposing a seismic isolation device between a support structure and a superstructure.
A rigidity switching device arranged in parallel with the seismic isolation device and having a variable rigidity for connecting the support structure and the upper structure, a sensor for detecting seismic motion or vibration of the support structure, and a seismic motion input from the sensor. Based on the vibration information of the support structure, the response of the superstructure to the support structure is calculated in real time according to the rigidity of the rigidity switching device, and switching to the non-resonant rigidity for the rigidity switching device is performed. A non-resonant semi-active seismic isolation structure characterized by providing a control device for instructing. 2. The non-resonant semi-active seismic isolation structure according to claim 1, wherein the rigidity switching device is capable of switching between a high rigidity state and a low rigidity state in two or three or more stages. . 3. The rigidity switching device is formed of an oil-sealed damper, and the rigidity between the support structure and the upper structure is made variable by adjusting the opening degree of a valve according to an instruction from the control device. 3. The non-resonant semi-active seismic isolation structure according to claim 1 or 2. 4. The apparatus according to claim 1, wherein the rigidity switching device is an ER fluid or an MR.
3. A stiffness between the support structure and the upper structure is variable by changing a strength of an electric or magnetic field, comprising a damper filled with a fluid.
Non-resonant semi-active seismic isolation structure described. 5. The non-resonant semi-active seismic isolation structure according to claim 1, wherein a spring element is connected in series with the rigidity switching device between the support structure and the upper structure. 6. A seismic isolation device for forming a seismic isolation layer between a support structure and an upper structure, and a rigidity switching device having a variable rigidity connecting the support structure and the upper structure are arranged in parallel. Then, based on the information of the seismic motion or the vibration of the support structure detected by the sensor, calculate the response of the superstructure expected according to the rigidity of the rigidity switching device in real time,
A non-resonant semi-active seismic isolation method, comprising: a control device for instructing the rigidity switching device to switch to non-resonant rigidity.