JP2009019383A - Base-isolating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base-isolating system which can exert a great vibration damping effect during an earthquake by using simple equipment, without the need for a computing unit, a complicated control unit or the like, and which can prevent the occurrence of excessive relative displacement between upper and lower structures during a big earthquake and the like. <P>SOLUTION: This base-isolating system comprises: a variable damper 4 which interposed between the upper and lower structures 1 and 2 of the building and which is provided with a switching means 4c for switching a damping coefficient between two stages or among three ones; a response detecting means 6 for detecting the response of the upper structure 2 to the lower structure 1; and a control means 7 for actuating the switching means 4c on the basis of a detection signal from the response detecting means 6. Characteristically, the control means 7 minimizes the damping coefficient of the variable damper 4 on the occurrence of the earthquake, increases a damping force by actuating the switching means 4c so as to increase the damping coefficient of the variable damper 4, when the response detecting means 6 detects the amount of the response of the upper structure 2, exceeding its set value, and maintains the damping coefficient as-is at least during the earthquake. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a seismic isolation system which is provided between upper and lower structures and can control the seismic isolation effect and response to the upper structure.

  In recent years, in order to ensure the safety of structures against earthquakes, earthquakes, etc. are installed on bases of the structures and seismic isolation layers provided on intermediate floors with laminated rubber and seismic isolation devices using sliding bearings. In addition to alleviating vibrations that are about to propagate from the ground to the structure, various passives are also used to actively dampen the vibrations by interposing damping dampers such as viscoelastic dampers and oil dampers between the upper and lower structures. Seismic isolation system is applied.

By the way, when setting the damping force in the damping damper, there is a conflicting relationship between the relative displacement between the upper and lower structures in the seismic isolation layer and the acceleration response of the upper structure.
That is, if the damping force is set high, the relative displacement in the seismic isolation layer can be reduced, but the vibration transmissibility to the superstructure increases and the acceleration response increases. On the other hand, if the damping force is set low, the acceleration response of the superstructure can be reduced, but on the other hand, the relative displacement in the seismic isolation layer becomes large. As a result, there is a large gap between the superstructure and the surroundings. It becomes necessary to set the clearance.

  Therefore, the damping force is set high for structures where the site is small and it is difficult to ensure sufficient clearance, or structures that aim to suppress relative displacement between the upper and lower structures against long-period ground motion. In such a case, there is a problem that the performance of reducing acceleration response deteriorates even for frequent small and medium earthquakes.

  For this reason, a seismic isolation system using a damping device proportional to the square of speed has also been developed. According to the seismic isolation system, since the generated damping force is proportional to the square of the speed, frequent small and medium earthquakes However, for large earthquakes with a large velocity, the seismic isolation effect can be reduced by increasing the damping force. It is possible to suppress an excessive relative displacement of.

However, in the conventional seismic isolation system, even when a large relative displacement occurs between the upper and lower structures, the damping force is set small in the region where the displacement speed V of the damping device is small. There is a problem that an excessive displacement generated in the above-described superstructure cannot be suppressed.
In addition, since the characteristic curve of the damping device is defined by the relationship between the displacement speed and the damping force, there is a problem that it is difficult to freely set the damping performance at the time of a small and large earthquake. .

  In order to solve such a problem, for example, in Patent Document 1 below, a variable attenuation device in which a resistance value can be changed in multiple steps or continuously according to a command value, and the resistance value can be varied by the command value. As a control means, a displacement meter that measures the amount of displacement of the attenuation device is installed, and based on the displacement signal X measured by the displacement meter, the arithmetic device first calculates and obtains the velocity V by differential operation, An index I is obtained by the following equation using a constant ω, I = √ {X2 + (V / ω) 2}, a command value C is calculated based on the index I, and a resistance value is controlled. A variable damping device has been proposed.

  In addition, the inventors previously described in Patent Document 2 below, an exemption for controlling the damping force of the seismic isolation means having a damping device having a variable damping force interposed between the upper and lower structures of the structure. A seismic control method that sets a reference amplitude value between the upper and lower structures in advance and measures a relative amplitude value and velocity between the upper and lower structures when vibration is applied to the structure. A predicted amplitude value after a predetermined time of the vibration is calculated from the amplitude value and speed, and then the damping force is controlled based on a difference between the predicted amplitude value and the reference amplitude value. A control method was proposed.

According to the above seismic isolation control method, the relative amplitude value and speed between the upper and lower structures when vibration is applied to the structure are measured, and the predicted amplitude value after a certain time of the vibration is calculated from these. Since the damping force is controlled based on the difference between the obtained predicted amplitude value and the reference amplitude value, for example, when the predicted amplitude value is larger than a preset reference amplitude value, the damping force is set. When the predicted amplitude value is smaller than the reference amplitude value, and the control is performed to reduce the damping force, etc. It is possible to reliably prevent the response displacement of the object from being excessively increased.
JP 2002-227925 A JP 2004-332837 A

  However, even in the above-mentioned seismic isolation control method, the relative amplitude value and speed between the upper and lower structures are measured from time to time using a sensor or the like, and the predicted amplitude value after a certain time of the vibration is constantly calculated from these. Development of a seismic isolation system that replaces the semi-active seismic isolation system that is even easier and more maintenance-reliable. Is desired.

  The present invention has been made in view of such circumstances, and without requiring an arithmetic device or a complicated control device, it is possible to exhibit a high vibration damping effect at the time of an earthquake with simple equipment, and at the time of a large earthquake, etc. An object of the present invention is to provide a seismic isolation system that replaces the semi-active seismic isolation system that can prevent excessive relative displacement between the upper and lower structures.

  In order to solve the above-mentioned problem, the seismic isolation system according to the invention described in claim 1 is provided between the upper and lower structures of the building and provided with switching means for switching the damping coefficient to two or three stages. A variable damping damper; response detection means for detecting a response of the upper structure to the lower structure; and control means for operating the switching means based on a detection signal from the response detection means. When the earthquake occurs, when the damping coefficient of the variable damping damper is minimized and the response detecting means detects a response amount of the superstructure exceeding the set value, the switching means is operated to operate the variable damping damper. The damping coefficient is increased to increase the damping force, and at least during the earthquake, the damping coefficient is maintained as it is.

The invention according to claim 2 is the invention according to claim 1, wherein the response detection means detects a response of the upper structure to the lower structure, and the response amount exceeds the set value. In this case, the control means is a switch for generating a trigger signal for operating the switching means.
Here, the response of the upper structure means the displacement amount, speed, acceleration of the upper structure relative to the lower structure, the relative displacement amount in the driving portion of the variable damping damper, the relative speed, the relative acceleration, the damping force, the internal pressure in the fluid damper, etc. Is included.

  The invention according to claim 3 is the invention according to claim 1 or 2, further comprising seismic sensing means for detecting the occurrence of an earthquake, and the variable damping damper is set to a maximum damping coefficient in normal times. And the control means operates the switching means based on an earthquake detection signal from the seismic sensing means to reduce the damping force by lowering the damping coefficient of the variable damping damper. It is.

  Furthermore, the invention according to claim 4 is the invention according to claim 3, wherein the seismic sensing means determines the magnitude of the seismic intensity and / or acceleration of the building before the S wave due to the earthquake arrives. It is possible to detect, and when the detected seismic intensity and / or acceleration exceeds a set value, the control means is set to issue a trigger signal for operating the switching means. Is.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the variable damping damper is a variable damping oil damper, and the switching means is connected to the variable damping oil damper. In addition, the solenoid valve is provided so that the damping coefficient of the variable damping oil damper becomes a maximum value when the current is not energized.

  Further, the invention according to claim 6 is the invention according to claim 5, wherein the control means receives the earthquake detection signal from the seismic sensing means and, after a lapse of a certain time, passes to the solenoid valve. A timer for turning off the power is provided.

  According to the invention described in any one of claims 1 to 6, since the damping coefficient of the variable damping damper is set to the minimum by the control means at the time of the occurrence of the earthquake, the transmission rate of the vibration to the superstructure is reduced. The acceleration response of the superstructure generated by the earthquake can be reduced. At this time, the relative displacement of the upper structure with respect to the lower structure is increased, but when the response amount of the upper structure to the lower structure detected by the response detection means exceeds a set value, the switching means is operated to vary. By increasing the damping force of the damping damper, the relative displacement of the superstructure can be suppressed.

  Therefore, it is possible to exert a high vibration damping effect at the time of an earthquake with a simple facility without requiring an arithmetic device or a complicated control device, and an excessive relative displacement occurs between the upper and lower structures at the time of a large earthquake. Can be prevented.

  In particular, according to the invention described in claim 3, since it has a seismic sensing means for detecting the occurrence of an earthquake, the variable damping damper is set to the maximum attenuation coefficient in normal times, and when an earthquake occurs For the first time, it is possible to increase the seismic isolation effect by actuating the switching means based on the earthquake detection signal from the seismic sensing means to reduce the damping force of the variable damping damper.

Here, as the seismic means, an S wave caused by an earthquake such as a P wave sensor installed on the ground in the vicinity of the building or an emergency earthquake information of the Japan Meteorological Agency as in the invention described in claim 4 is used. It is preferable to use means for informing the occurrence of the earthquake before reaching the building.
When the seismic sensing means detects the occurrence of an earthquake, the switching means may be actuated immediately to reduce the damping force of the variable damping damper. If the control means is set to issue a trigger signal for operating the switching means, the switching means will not operate frequently, and therefore maintenance and reliability of the switching means and the variable damping damper are avoided. Property can be further improved.

  Further, as the variable damping damper and the switching means, a general-purpose variable damping oil damper or a solenoid valve can be used as in the invention described in claim 5, and in particular, the solenoid valve has a damping force when not energized. If it is provided so as to have a maximum value, it is not necessary to supply power during normal times, so that it is excellent in economic efficiency and handleability.

  In addition, as in the invention described in claim 6, if a timer for turning off the energization of the solenoid valve is provided after a predetermined time has elapsed after receiving the earthquake detection signal from the seismic sensing means, In this case, the solenoid valve can be returned to the normal setting again without any operation.

1-6 shows one Embodiment of the seismic isolation system which concerns on this invention, and its modification.
This seismic isolation system includes a seismic isolation device 3 a and a variable damping oil damper (variable damping damper) 4, which are provided with a laminated rubber support interposed in a seismic isolation layer 3 formed between a lower structure 1 and an upper structure 2 of a building. A seismic sensing means 5 for detecting the occurrence of an earthquake, a limit switch (response detecting means) 6 for detecting a relative displacement (response) of the upper structure 2 with respect to the lower structure 1 due to the earthquake, a seismic means 5 and a limit A relay circuit (control means) 7 for increasing or decreasing the damping force of the variable damping oil damper 4 based on a detection signal from the switch 6 is schematically configured.

  Here, the variable damping oil damper 4 has two stages of damping coefficient by switching between a cylinder 4a filled with oil, an output shaft 4b reciprocally provided in the cylinder 4a, and an internal oil passage. The output shaft 4 b is fixed to the lower structure 1 and the cylinder 4 a is fixed to the upper structure 2. In this variable damping oil damper 4, the electromagnetic valve 4c is normally closed, and as a result, the damping coefficient is large (Cmax) when not energized (power supply OFF), and the damping coefficient is small (Cmim) when energized (power source ON). It is set to be.

  As the seismic sensing means 5, a seismometer installed on the lower structure 1 or nearby ground, or a receiving device such as emergency earthquake information of the Japan Meteorological Agency can be used. By the way, according to the emergency earthquake information, it is possible to predict the seismic intensity and the magnitude of acceleration at this building position before the earthquake arrives. The seismic sensing means 5 includes a value (for example, about 1 if the seismic intensity is about 1 degree of acceleration) in which the magnitude of the earthquake (in this embodiment, seismic intensity or acceleration) received from the seismometer or receiving device is set. In this case, an output line 8 is connected to send a trigger signal when the value exceeds several Gal). Incidentally, when the seismometer is used, a P-wave sensor capable of setting such a trigger signal is suitable.

The limit switch 6 for detecting the relative displacement is provided between the upper and lower structures 1 and 2 in the seismic isolation layer 3.
As shown in FIG. 3, the limit switch 6 is mounted on a proximity switch 9 that is suspended from the upper structure 2 and has a tip 9 a that can detect metal, and a lower structure 1 that faces below the proximity switch 9. And the detection plate 10.

  The detection plate 10 is formed with a non-ferrous metal plate 10a in a circular portion centered on the lower side of the proximity switch 9 in a normal state, and a metal plate 10b is provided on the outer periphery thereof. The radius of the non-ferrous metal plate 10a is a set value of the relative displacement amount of the upper structure 2 with respect to the lower structure 1. The proximity switch 9 is connected to an output line 11 that sends the detection signal as a trigger signal when the proximity switch 9 is located above the metal plate 10b and detects metal.

  On the other hand, the relay circuit 7 is a solid state relay circuit, and includes a trigger from the proximity switch 9 of the input line 12 from the power source, the power output line 13 to the solenoid valve, the sensing means 5 and the limit switch 6. Signal output lines 8 and 11 are connected, and a timer 14 is interposed in the output line 8 from the sensing means 5.

  The relay circuit 7 keeps the switch 7a between the power input line 12 and the power output line 13 to the solenoid valve 4c OFF during normal operation and outputs a trigger signal generated from the seismic sensing means 5. When the signal is input via the line 8, the switch 7a is turned on to energize the solenoid valve 4c, and when the trigger signal generated from the limit switch 6 is input via the output line 11, the switch is switched again. 7a is turned off. The timer 14 is set so as to issue a signal for turning off the switch 7a to the relay circuit 7 after a predetermined time (for example, 12 hours or 24 hours) has elapsed after receiving the trigger signal from the seismic means 5. Has been.

In the seismic isolation system having the above configuration, as shown in FIG. 2 and FIG. 4, since the power to the electromagnetic valve 4 c is normally de-energized by the relay circuit 7, the variable damping oil damper 4 The attenuation coefficient is set to Cmax.
When an earthquake exceeding the preset value occurs, a trigger signal is input from the seismic sensing means 5 that detects this, and the switch 7a is turned on to energize the solenoid valve 4c. Is done.

As a result, the damping coefficient of the variable damping damper 4 is switched to Cmin and the damping force is increased, so that the relative displacement generated between the upper and lower structures 1 and 2 can be effectively absorbed to attenuate the vibration.
This also increases the amount of relative displacement in the upper structure 2 with respect to the lower structure 1, but the tip 9 a of the proximity switch 9 suspended from the upper structure 2 is connected to the metal plate 10 b of the detection plate 10 provided in the lower structure 1. When the upper structure 2 is relatively displaced upward, a trigger signal from the proximity switch 9 that detects metal is input from the output line 11 to the relay circuit 7.

  Then, the switch 7a is switched to OFF again in the relay circuit 7, the solenoid valve 4c is deenergized, and the damping coefficient of the variable damping oil damper 4 becomes Cmax. Thereby, although the vibration damping effect is reduced, excessive relative displacement in the upper structure 2 can be suppressed. Even if the earthquake that occurred is small and medium, and the trigger signal from the limit switch 6 is not finally issued, the earthquake detection signal from the seismic sensing means 5 is received and a certain time has passed. Since the timer 14 is activated and the energization of the solenoid valve 4c is cut off, the solenoid valve 4c can be returned to the non-energized state in normal times without any operation.

  Therefore, according to the seismic isolation system that switches the damping coefficient in two stages, it is possible to exhibit a high vibration damping effect during an earthquake with a simple facility without requiring an arithmetic device or a complicated control device, and a large earthquake. In some cases, excessive relative displacement between the upper and lower structures 1 and 2 can be prevented. In addition, the electromagnetic valve 4c of the variable damping oil damper 4 is provided so that the damping force is large (attenuation coefficient: Cmax) when not energized, and is energized when the earthquake occurs so that the damping force is small (attenuation coefficient: Cmin). For this reason, it is not necessary to supply power during normal times, so that the economy and handling are excellent.

  Furthermore, when the seismic sensing means 5 detects the occurrence of an earthquake, when the detected seismic intensity or acceleration exceeds the set value, a trigger signal for turning on the switch 7a for the first time in the relay circuit 7 is provided. Therefore, the relay circuit 7 does not frequently operate due to vibrations or extremely small earthquakes caused by transportation or strong winds that occur in normal times, and therefore the solenoid valve 4c and the variable damping oil damper. Maintenance / reliability in 4 can be further improved.

  In the above embodiment, the case where the limit switch 6 using the proximity switch 9 is applied as the response detecting means has been described. However, the present invention is not limited to this, and for example, a displacement as shown in FIG. 5 or FIG. Limit switches 17 and 18 using the switch 15 and the dock 16 can also be used.

  That is, the limit switch 17 shown in FIG. 5 is provided with a mounting plate 19 that extends to the lower side of the cylinder 4 a on the output shaft 4 b of the variable damping oil damper 4, and the displacement switch 15 is mounted on the tip of the mounting plate 19. It has been. The displacement switch 15 protrudes toward the cylinder 4a, and a sensing portion 15a is provided at the tip so as to be swingable in the horizontal direction. On the other hand, a dock 16 is provided on the bottom surface of the cylinder 4 a located above the displacement switch 15.

  The dock 16 is formed in a concave shape above the position of the displacement switch 15 in normal times, and an inclined surface 16a is formed on the outer periphery of the dock 16 so as to gradually protrude downward in the horizontal direction. When a horizontal relative displacement exceeding a set value occurs between the cylinder 4a (upper structure 2) and the output shaft 4b (lower structure 1) when an earthquake occurs, the sensing unit 15a has the inclined surface 16a of the dock 16. The detection signal is transmitted as a trigger signal from the output line 11 to the relay circuit 7 as described above.

Further, the limit switch 18 shown in FIG. 6 is provided with a mounting plate 20 on the cylinder 4a (upper structure 2) side, a displacement switch 15 at the tip of the mounting plate 20, and a sensing unit 15a facing downward. The dock 16 is fixed to the upper surface of the lower structure 1 facing the displacement switch 15.
Such limit switches 17 and 18 can provide the same effects as when the limit switch 6 is used.

Next, in order to confirm the effect of the seismic isolation system according to the present invention, the seismic response analysis from the small and medium earthquake to the large earthquake was performed using the seismic isolation building analysis model.
First, as shown in FIG. 7, a building using the above-mentioned seismic isolation system has laminated rubber + variable damping oil on the foundation of a 9-story small steel building (natural period of superstructure 1.2 seconds). A model that applies a seismic isolation system composed of dampers is assumed.

  Here, the primary natural period of the entire seismic isolation building is set to 3 seconds, and as a variable damping oil damper, as shown in FIG. 8, the damping coefficients are Cmax = 19 kN / kine and Cmin = 5.6 kN / kine 2 A step switching type was used. The seismic isolation clearance with the retaining wall in the seismic isolation layer was 15 cm, and the limit switch was set to operate when the deformation of the seismic isolation layer exceeded 8 cm. In addition, the variable damping oil damper sets the damping coefficient to Cmin until the limit switch is activated, switches the damping coefficient to Cmax when the limit switch is activated, and maintains the damping coefficient at Cmax until the shaking of the earthquake subsides. .

  9 and 10 show the input acceleration, the building top acceleration (FIG. 9), and the seismic isolation layer displacement (FIG. 10) when the input acceleration of the El Centro NS wave is increased at a pitch of 25 cm / s 2 with respect to the above model. It is the analysis result which shows the relationship. In the figure, the result of the passive damper in which the damping coefficient is fixed to constant values of Cmax = 19 kN / kine and Cmin = 5.6 kN / kine is also shown.

  According to FIGS. 9 and 10 showing these analysis results, in the passive damper with the damping coefficient fixed to Cmin, although the acceleration response at the top is small, the seismic isolation layer is deformed at an input acceleration of about 300 cm / s2. It can be seen that it collides with the retaining wall beyond 15 cm. On the other hand, in the passive damper with the damping coefficient fixed at Cmax, the response of the seismic isolation layer is kept within 15 cm even during a large earthquake, but compared with the case where the top acceleration is fixed at the damping coefficient Cmin even during a small and medium earthquake. It turns out that it will become big.

On the other hand, in the seismic isolation system according to the present invention, while the input level is small, the acceleration response is equivalent to the case where the attenuation coefficient is fixed to Cmin, and the response value attenuates as the input level increases. It is asymptotic when the coefficient is fixed at Cmax. And since the attenuation coefficient is maintained at Cmin up to about 200 cm / s2, the acceleration reduction performance for small and medium earthquakes is excellent, and when it exceeds 200 cm / s2, the attenuation coefficient switches to Cmax. However, the response of the seismic isolation layer has been subsided to 15 cm or less.
From the above, when focusing on the maximum response value, it was confirmed that the seismic isolation system according to the present invention can provide practically sufficient performance.

  In the above embodiments and examples, only the case where the variable damping oil damper 4 is used as the variable damping damper and the electromagnetic valve 5 is used as the switching means has been described. However, the present invention is not limited to this. Various variable damping dampers and switching means for switching the damping force of the damper can be applied. Also, the switching step of the attenuation coefficient is not limited to the two steps described above, but one that can be switched to three steps may be used.

  Further, the seismic sensing means 5 and the timer 14 can be omitted, and the damping coefficient can be set to Cmin by always energizing the solenoid valve 5 at normal times. In this case, it is necessary to always energize, but in other respects, the same effects as those described in the above embodiment can be obtained.

It is a longitudinal cross-sectional view of the seismic isolation layer part in the building to which one Embodiment of the seismic isolation system which concerns on this invention is applied. It is a schematic block diagram of the seismic isolation system of FIG. FIG. 3 shows the limit switch of FIG. 2, (a) is an enlarged view of a part A in FIG. 1, and (b) is a bb line view of (a). It is a block diagram which shows the relationship of the action | operation of the said seismic isolation system, and switching of a damping coefficient. It is a front view which shows the modification of the limit switch of FIG. FIG. 9 shows another modification of the limit switch of FIG. 3, (a) is a front view, and (b) is a side view. It is a figure which shows the seismic isolation building analysis model used for the Example of this invention. It is a graph which shows the relationship between the speed and damping force in each damping coefficient of the variable damping damper used for the said Example. It is a graph which shows the relationship between the input acceleration in the analysis result of the said Example, and a top part acceleration. It is a graph which shows the relationship between the input acceleration and the seismic isolation layer deformation | transformation in the analysis result of the said Example.

Explanation of symbols

1 Substructure 2 Upper structure 3 Seismic isolation layer 4 Variable damping oil damper (variable damping damper)
4a Cylinder 4b Output shaft 4c Solenoid valve (switching means)
5 Seismic sensing means 6, 17, 18 Limit switch (response detection means)
7 Relay circuit (control means)
7a switch

Claims (6)

A variable damping damper interposed between the upper and lower structures of the building and provided with switching means for switching the damping coefficient to two or three stages; response detecting means for detecting the response of the upper structure to the lower structure; Control means for operating the switching means based on a detection signal from the response detection means,
The control means activates the switching means to minimize the damping coefficient of the variable damping damper when an earthquake occurs and the response detecting means detects a response amount of the superstructure that exceeds the set value. A seismic isolation system characterized by increasing the damping coefficient of the variable damping damper to increase the damping force and maintaining the damping coefficient as it is at least during an earthquake.   The response detection means is a switch for detecting a response of the upper structure to the lower structure and generating a trigger signal for operating the switching means to the control means when the response amount exceeds the set value. The seismic isolation system according to claim 1.   It has seismic sensing means for detecting the occurrence of an earthquake, and the variable damping damper is set to a maximum attenuation coefficient in normal times, and the control means is based on an earthquake detection signal from the seismic sensing means. The seismic isolation system according to claim 1 or 2, wherein the switching means is operated to reduce the damping force by lowering the damping coefficient of the variable damping damper.   The seismic sensing means can detect the magnitude and / or acceleration magnitude of the earthquake in the building before the S wave due to the earthquake arrives, and the detected seismic intensity and / or acceleration of the earthquake can be set to a set value. 4. The seismic isolation system according to claim 3, wherein when it exceeds, the control means is set to issue a trigger signal for operating the switching means.   The variable damping damper is a variable damping oil damper, and the switching means is a solenoid valve that switches a flow path of hydraulic oil to the variable damping oil damper. The seismic isolation system according to any one of claims 1 to 4, wherein the damping coefficient of the oil damper is set to a maximum value.   The said control means is provided with the timer which cuts off the electricity supply to the said solenoid valve, after receiving the detection signal of the earthquake from the said seismic sensing means, and a fixed time passes. Seismic isolation system.

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