Seismic isolation system

Abstract

To prevent air more than necessary from being supplied to an air chamber 11.SOLUTION: A base isolation system 1 includes an air chamber 11 provided between an upper structure 100 and an artificial ground 200, an air tank 13 for storing compressed air, a control valve 15 whose opening / closing state is controlled, a vibration sensor 12 for detecting vibration, and a control device 16. The control device 16 controls the control valve 15 to supply air to the air room 11 when the detection signal of the vibration sensor 12 indicates earthquake motion in the normal mode, floats the upper structure 100 to the determination height H1 lower than the specified height H12, and shifts to the determination mode, and controls the control valve 15 to supply air to the air room 11 when the detection signal of the vibration sensor 12 indicates earthquake motion in the determination mode, and floats the upper structure 100 again to the height equal to or lower than the specified height H1.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a seismic isolation system. [Background technology]

[0002] A seismic isolation system is known that uses air to lift a superstructure off the ground, thereby reducing the effects of earthquake motion on the superstructure. For example, Patent Document 1 describes a configuration in which, in the event of an earthquake, high-pressure air is supplied from a compressor to the inside of an air bearing, causing the building to float from its support. Patent Document 2 also describes a seismically isolated building that includes an air film forming device (air bearing) installed between the building and the ground, an air supply source (compressor, air tank) that supplies air to the air film forming device, an acceleration detector, and a control device, and in the event of an earthquake, compressed air is supplied from the air supply source to the air film forming device, thereby lifting the building off the ground and isolating it from seismic activity.

[0003] In the configuration of Patent Document 1, when an earthquake is detected by an earthquake detection device, air is ejected from an air bearing installed between the building and the foundation, causing the building to float up from its support. In the configuration of Patent Document 2, when the control device receives earthquake information, it starts supplying air from the air supply source to the air film forming device, and if the acceleration value input from the acceleration detector after receiving the earthquake information is below a predetermined value for a certain period of time, it stops the supply of air from the air supply source.

[0004] Patent Document 1 does not mention the amount of compressed air to be supplied to the air bearings when an earthquake occurs. In Patent Document 2, the air supply source continues to supply air until the acceleration value input from the acceleration detector falls below a predetermined value within a certain period of time. Therefore, there is a risk that more air than necessary may be supplied to the air chamber in the configurations of Patent Documents 1 and 2. For example, if air is supplied to the air bearings based on the detection of the first arriving P wave when an earthquake occurs, but the subsequently arriving S wave is relatively small and there is no need to lift the building, unnecessary air may be supplied to the air bearings. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 5-63580 [Patent Document 2] Patent No. 5264241 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent more air than necessary from being supplied to the air chamber. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the seismic isolation system of the present invention comprises: an air chamber that is provided between an upper structure and a support part that supports the upper structure, that expands when supplied with air to lift the upper structure off the support part, and after expansion, contracts under the weight of the upper structure to lower the upper structure; an air tank that stores compressed air; a control valve that is provided on a communication path that airtightly connects the air chamber and the air tank and whose open / close state is controlled; vibration detection means that detects vibrations; and control means that controls the control valve based on vibration detection information from the vibration detection means, wherein the control means, in a normal mode that is set under normal circumstances, when the vibration detection information indicates seismic motion, controls the control valve to supply air to the air chamber, so that the upper structure is lifted to a judgment height that is lower than a specified height, and then switches to a judgment mode, and when the vibration detection information indicates seismic motion in the judgment mode, controls the control valve to supply air to the air chamber, so that the upper structure is lifted again to a height equal to or lower than the specified height. [Effects of the Invention]

[0008] According to the seismic isolation system of the present invention, it is possible to prevent more air than necessary from being supplied to the air chamber. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view illustrating the configuration of a seismic isolation system. [Figure 2] (a) is a cross-sectional view showing the state in which the upper structure has been levitated to a specified height, and (b) is a timing chart showing the control signal of the control valve and the levitation height of the upper structure. [Figure 3] FIG. 2A is a perspective view illustrating the overall configuration of the sealing member, and FIG. 2B is an enlarged cutaway view of a corner portion of the sealing member. [Figure 4] FIG. 1 is a block diagram illustrating the configuration of a seismic isolation system. [Figure 5] FIG. 2 is a functional block diagram of the seismic isolation system. [Figure 6](a) is a cross-sectional view showing the state immediately after the control valve is opened, and (b) is a timing chart showing the acceleration applied to the upper structure, the control signal of the control valve, and the levitation height of the upper structure. [Figure 7] (a) is a cross-sectional view showing the state in which the upper structure has been levitated to the judgment height, and (b) is a timing chart showing the acceleration applied to the upper structure, the control signal of the control valve, and the levitation height of the upper structure. [Figure 8] (a) is a cross-sectional view showing the state in which the upper structure has transitioned to normal mode without being re-floated, and (b) is a timing chart showing the acceleration applied to the upper structure, the control signal of the control valve, and the levitation height of the upper structure. [Figure 9] (a) is a cross-sectional view showing the state in which the upper structure has been refloated, and (b) is a timing chart showing the acceleration applied to the upper structure, the control signal of the control valve, and the levitation height of the upper structure. [Figure 10] 10 is a flowchart showing common control of the seismic isolation system. [Figure 11] 10 is a flowchart showing control of the seismic isolation system in normal mode. [Figure 12] 10 is a flowchart showing control of the seismic isolation system in a determination mode. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Outline of Seismic Isolation System 1> First, we will explain the outline of the seismic isolation system 1. However, unless otherwise specified, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and do not intend to limit the scope of the present invention. Figure 1 is a cross-sectional view explaining the configuration of the seismic isolation system 1, Figure 2(a) is a cross-sectional view showing the state in which the upper structure 100 has been raised to a specified height, and Figure 2(b) is a timing chart showing the control signal of the control valve 15 and the raised height of the upper structure 100.

[0011] The seismic isolation system 1 illustrated in FIG. 1 includes an air chamber 11 provided between an upper structure 100 and an artificial ground 200 (bearing portion) that supports the upper structure 100. Under normal circumstances when no earthquake has occurred, the bottom surface of the superstructure 100 is supported on the top surface of the artificial ground 200, and the air chamber 11 is a gap formed between the bottom surface of the superstructure 100 and the top surface of the artificial ground 200. When an earthquake occurs, the air chamber 11 expands upward as air is supplied to it, as shown in Figure 2(a).

[0012] The inflation of the air chamber 11 causes the superstructure 100 to rise from the artificial ground 200. Fig. 2(a) shows an example in which the superstructure 100 has been raised to a specified height H1. Here, the specified height H1 will be explained. The specified height H1 is determined based on the time required for an earthquake to converge, and is determined to be a height that allows the upper structure 100 to be lifted for the standard time required for an earthquake of a specified seismic intensity or greater to converge, for example.

[0013] Returning to Figure 1, the seismic isolation system 1 includes, in addition to the air chamber 11 mentioned above, a vibration sensor 12 (vibration detection means) that detects vibrations, an air tank 13 that stores compressed air, an air supply pipe 14 (communication path) that connects the air tank 13 and the air chamber 11, a control valve 15 that is provided midway along the air supply pipe 14 and whose open / close state can be controlled externally, and a control device 16 (control means) that receives the detection signal of the vibration sensor 12 (vibration detection information from the vibration detection means) and controls the control valve 15.

[0014] In a normal state in which the superstructure 100 is supported by the artificial ground 200, the superstructure 100 is fixed to the artificial ground 200 by its own weight. Therefore, when an earthquake occurs, the superstructure 100 sways integrally with the artificial ground 200 (i.e., the ground 300). Under normal conditions, when a detection signal indicating seismic movement is input from the vibration sensor 12 to the control device 16, the control device 16 opens the control valve 15 for a specified time, and raises the upper structure 100 to a judgment height H12 (see Figure 2(a)), which is lower than the above-mentioned specified height H1.

[0015] Thereafter, the control device 16 transitions to a determination mode and monitors the detection signal from the vibration sensor 12. If a detection signal indicating seismic motion is input from the vibration sensor 12 during the determination mode, the control device 16 opens the control valve 15 for a specified time, and refloats the upper structure 100 to a height equal to or less than the specified height H1 (for example, the refloating height H23 shown in FIG. 9(a)). On the other hand, if a detection signal indicating seismic motion is not input from the vibration sensor 12 during the determination mode, the control device 16 transitions to a normal mode.

[0016] In the seismic isolation system 1 having the above configuration, when earthquake motion is detected during normal mode, the upper structure 100 is raised to a judgment height H12. Because the judgment height H12 is lower than the specified height H1, the amount of air supplied to the air chamber 11 can be less than when the upper structure 100 is raised to the specified height H1. When the upper structure 100 is raised to the judgment height H12, the system switches to judgment mode. If seismic motion is detected during judgment mode, the upper structure 100 is re-floated, thereby protecting the upper structure 100 from seismic motion. On the other hand, if no seismic motion is detected during judgment mode, the upper structure 100 gently descends under its own weight and is supported by the artificial ground 200. In this case, the upper structure 100 is not re-floated, thereby reducing the consumption of air for re-floating.

[0017] <Artificial ground 200> The following is a detailed description of the seismic isolation system 1. First, the artificial ground 200 will be described. As shown in Fig. 1, the artificial ground 200 is made of, for example, reinforced concrete and is provided on the surface of the ground 300. The illustrated planar shape of the artificial ground 200 is, for example, a square, but is not limited to this example. In this embodiment, the upper surface 200a of the artificial ground 200 (see Fig. 2(a)) is finished to improve airtightness. This finishing is performed to improve adhesion with a seal member 130 (see FIG. 3, described later) provided at the bottom of the upper structure 100, and to ensure airtightness of the air chamber 11. In this embodiment, the artificial ground 200 is used as an example of the bearing portion, but the bearing portion is not limited to the artificial ground 200 as long as it is provided on the ground 300 and can support the superstructure 100.

[0018] <Superstructure 100> As shown in FIG. 1, the superstructure 100 includes an upper foundation 110 , a structure body 120 provided on the upper foundation 110 , and a seal member 130 provided below the upper foundation 110 . Although the illustrated upper structure 110 has a rectangular shape in a plan view, various shapes may be adopted. For example, the upper structure 110 may have an elliptical shape in a plan view, or may have a polygonal shape other than a rectangular shape.

[0019] The upper foundation 110 is made of, for example, reinforced concrete, and includes a foundation main body 111 and a foundation wall portion 112 that rises upward from the outer periphery of the top surface of the foundation main body 111. The foundation body 111 is a thick plate-shaped portion with sufficient thickness to support the structure body 120, and has a flat bottom surface 111a (see, for example, Figure 2(a)) facing the upper surface 200a of the artificial ground 200. The planar shape of the base body 111 is not limited to a square shape either, and various shapes can be adopted. Furthermore, an insertion hole 113 is provided in the base body 111 along the thickness direction (vertical direction). An air supply pipe 14 that connects the air chamber 11 and the air tank 13 is inserted into the insertion hole 113. The outer peripheral surface of the air supply pipe 14 and the inner peripheral surface of the insertion hole 113 are airtightly sealed.

[0020] The structure body 120 is a building constructed on the upper foundation 110, and includes, for example, peripheral walls 121, a floor 122, and a roof (not shown). The structure body 120 may be a wooden structure or a reinforced concrete structure.

[0021] FIG. 3(a) is a perspective view illustrating the overall configuration of the seal member 130, and FIG. 3(b) is an enlarged cutaway view of a corner portion of the seal member 130. The sealing member 130 is a frame-shaped member made, for example, from a rigid and elastic plate material, and is provided for the purpose of forming an airtight air chamber 11 between the bottom surface 111a of the upper foundation 110 and the top surface 200a of the artificial ground 200. The sealing member 130 includes a mounting frame 131 attached to the base body 111 and a movable plate piece 132 extending obliquely downward from the lower edge of the mounting frame 131.

[0022] The mounting frame 131 is provided along the lower part of the outer peripheral surface of the foundation body 111 and is fixed in an airtight manner to the outer peripheral surface of the foundation body 111. Since the foundation body 111 in this embodiment has a rectangular shape in a plan view, the mounting frame 131 is formed of a rectangular frame body of the same size as the foundation body 111. The shape of the mounting frame 131 can take various shapes depending on the shape of the foundation body 111. Furthermore, various fixing methods can be used to fix the mounting frame 131 to the foundation body 111 as long as the fixing method can securely and airtightly fix the mounting frame 131 to the foundation body 111.

[0023] The movable plate piece 132 is integrally formed with the mounting frame body 131 from the lower edge of the mounting frame body 131, and is a frame-like combination of plate pieces bent diagonally downward toward the inside of the foundation body 111 (superstructure 100). The movable plate pieces 132 are elastic and deform according to the floating height of the superstructure 100. For example, in the supported state of the superstructure 100 shown in Fig. 1, the inner peripheral portion of the movable plate pieces 132 is sandwiched and constrained between the upper surface 200a of the artificial ground 200 and the bottom surface 111a of the foundation body 111, but the movable plate pieces 132 tend to expand due to their elastic force.

[0024] 2(a), when the upper structure 100 rises, the movable plate piece 132 expands in accordance with the rising height of the upper structure 100. At that time, the lower end edge 132a of the movable plate piece 132 remains pressed against the upper surface 200a of the artificial ground 200. As described above, the upper surface 200a of the artificial ground 200 is finished to enhance airtightness, so when the lower end edge 132a of the movable plate piece 132 is pressed against the upper surface 200a of the artificial ground 200, leakage of air from the air chamber 11 to the outside is suppressed. Therefore, as air continues to be supplied into the air chamber 11, the air chamber 11 expands upward, and the superstructure 100 rises. Then, the movable plate piece 132 expands toward the outside of the foundation body 111 while pressing the lower end edge 132a against the upper surface 200a of the artificial ground 200.

[0025] <Seismic isolation system 1> As explained in Figure 1, the seismic isolation system 1 comprises an air chamber 11, a vibration sensor 12 that detects vibrations of the upper structure 100, an air tank 13 that stores compressed air, an air supply pipe 14 that connects the air tank 13 and the air chamber 11, a control valve 15 provided midway along the air supply pipe 14, and a control device 16 that receives the detection signal from the vibration sensor 12 and controls the control valve 15. In addition, the seismic isolation system 1 is equipped with a proximity sensor 17 (floating height detection means) that detects the floating height of the upper structure 100, a pressure sensor 18 that detects the air pressure in the air tank 13, a compressor 19 that increases the pressure of the compressed air in the air tank 13, a control relay 20 whose operation is controlled by the control device 16 and that supplies commercial power to the compressor 19, and a storage battery 21 that can supply power in the event of a power outage.

[0026] The vibration sensor 12 is configured by, for example, an acceleration sensor provided on the upper foundation 110 , and detects the acceleration of the upper foundation 110 as vibrations applied to the upper structure 100 . The location where the vibration sensor 12 is provided is not limited to the upper foundation 110. For example, the vibration sensor 12 may be provided in the structure main body 120, or may be provided on the artificial ground 200 or the ground 300. By providing the vibration sensor 12 on the artificial ground 200 or the ground 300, earthquakes can be detected more directly than on the upper structure 100 (upper foundation 100), and the seismic isolation performance of the upper structure 100 against small earthquake motions can be improved.

[0027] Various types of acceleration sensors can be used for the vibration sensor 12. For example, a uniaxial acceleration sensor, a biaxial acceleration sensor, or a triaxial acceleration sensor may be used. Furthermore, a biaxial or triaxial acceleration sensor may be configured by using multiple uniaxial acceleration sensors. Furthermore, the vibration sensor 12 may be configured by a sensor other than an acceleration sensor. For example, the vibration sensor 12 may be configured by a displacement sensor.

[0028] The detection signal of the vibration sensor 12 (the magnitude of acceleration detected by the vibration sensor 12) is input as vibration detection information to the control device 16. In this embodiment, the vibration sensor 12 operates by obtaining operating power from the control device 16.

[0029] The air tank 13 is disposed in a space surrounded by a foundation wall 112 of the upper foundation 110 (for convenience, referred to as an underfloor space), but is not limited to this configuration. For example, the air tank 13 may be installed on the ground 300. The air tank 13 stores compressed air to be supplied to the air chamber 11. For example, the stored compressed air has a pressure that can repeatedly raise the superstructure 100 supported on the artificial ground 200 to a specified height H1 (see FIG. 2) a specified number of times or more.

[0030] In this embodiment, the specified height H1 is set to, for example, a height at which the upper structure 100 can be levitated for a specified period of time or more, and is obtained in advance by actually levitating the upper structure 100, for example. The judgment height H12 is determined based on the standard time interval between the arrival of the first vibration (e.g., P wave) and the second vibration (e.g., S wave) when an earthquake occurs. For example, the judgment height H12 is determined to be a height at which the upper structure 100, which has been raised in response to the arrival of the first vibration, can continue to rise until the second vibration arrives.

[0031] The air supply pipe 14 is a tubular member that can withstand high pressure, with one end connected to the air tank 13 and the other end opening to the air chamber 11, and is configured, for example, from an iron pipe, but may also be a tubular member made of a different material. The control valve 15 is provided at a position on the air supply pipe 14 closer to the air tank 13 than the base body 111. The control valve 15 operates on commercial power when there is no power outage, and operates by receiving power from the storage battery 21 when there is a power outage.

[0032] The proximity sensor 17 is provided, for example, on the bottom side of the upper foundation 110, and detects the distance between it and the upper surface 200a of the artificial ground 200 as the lift-up height of the upper structure 100, and inputs this as lift-up height detection information to the control device 16. In this embodiment, the proximity sensor 17 operates by obtaining operating power from the control device 16. The proximity sensor 17 may be, for example, a type that detects changes in electrical capacitance depending on the distance from the upper surface 200a of the artificial ground 200, but any type may be used as long as it can detect the distance from the upper surface 200a of the artificial ground 200.

[0033] The pressure sensor 18 detects the pressure inside the air tank 13, and is disposed, for example, inside the air tank 13. In this embodiment, the pressure sensor 18 obtains operating power from the control device 16 to operate. The pressure sensor 18 may be disposed outside the air tank 13 as long as it can detect the pressure inside the air tank 13. For example, the pressure sensor 18 may be provided in the air supply pipe 14 between the control valve 15 and the air tank 13.

[0034] The compressor 19 is connected to the air tank 13 through a connecting pipe 22, and compresses air and supplies it to the air tank 13. When compressed air is supplied from the compressor 19, the pressure of the compressed air in the air tank 13 is increased. The compressor 19 is operated by commercial power, and the commercial power is supplied to the compressor 19 via a control relay 20. The operation of the control relay 20 is controlled by a control signal from the control device 16, so that the control device 16 can control the operation of the compressor 19. The storage battery 21 is charged by commercial power when there is no power outage, and supplies power for operating the control device 16 and the control valve 15 when there is a power outage.

[0035] Next, a description will be given of the control device 16. Fig. 4 is a block diagram illustrating the configuration of the seismic isolation system 1, and Fig. 5 is a functional block diagram of the seismic isolation system 1. 4, the control device 16 includes a CPU 16a and a memory 16b. The CPU 16a is a calculation means, and controls the overall operation of the seismic isolation system 1. The memory 16b is a storage medium for storing information, and is used as a work area when the CPU 16a processes information, and stores a computer program (hereinafter referred to as a program) for operating the CPU 16a.

[0036] As shown in FIG. 5, the CPU 16a executes the programs stored in the memory 16b, whereby the control device 16 functions as a control means 16A that executes various operations. For example, the control means 16A acquires vibration detection information from the vibration detection means 12A (vibration sensor 12) and determines whether the vibration detection information indicates seismic motion. If it determines that the vibration detection information indicates seismic motion, the control means 16A controls the control valve 15 to supply compressed air in the air tank 13 to the air chamber 11. Furthermore, the control device 16 acquires flying height information from the flying height detection means 17A (proximity sensor 17), and switches from the determination mode to the normal mode based on the flying height information.

[0037] <Example of operation of Seismic Isolation System 1> An example of the operation of the seismic isolation system 1 will now be described. Figure 6(a) is a cross-sectional view showing the state immediately after the control valve 15 is opened, Figure 6(b) is a timing chart showing the acceleration applied to the upper structure 100, the control signal of the control valve 15, and the levitation height of the upper structure 100, Figure 7(a) is a cross-sectional view showing the state when the upper structure 100 has been levitated to the judgment height H12, and Figure 7(b) is a timing chart showing the acceleration applied to the upper structure 100, the control signal of the control valve 15, and the levitation height of the upper structure 100. Figure 8(a) is a cross-sectional view showing the state in which the upper structure 100 has transitioned to normal mode without being re-floated, Figure 8(b) is a timing chart showing the acceleration applied to the upper structure 100, the control signal of the control valve 15, and the levitation height of the upper structure 100, Figure 9(a) is a cross-sectional view showing the state in which the upper structure 100 has been re-floated, and Figure 9(b) is a timing chart showing the acceleration applied to the upper structure 100, the control signal of the control valve 15, and the levitation height of the upper structure 100.

[0038] The control device 16 sets the normal mode during normal times when no earthquake is occurring. As shown in Figures 6(a) and (b), in the normal mode, the control device 16 monitors the detection signal from the vibration sensor 12 (in this example, the acceleration applied to the upper structure 100) and determines whether the magnitude of the detection signal from the vibration sensor 12 exceeds thresholds TH1 and TH2. The thresholds TH1 and TH2 are determined as magnitudes indicative of seismic motion through experiments or the like, and are stored in advance in the memory 16b of the control device 16. As can be seen from FIG. 6(a), in normal mode the upper structure 100 sways together with the artificial ground 200 (ground 300), so the magnitude of the detection signal from the vibration sensor 12 in normal mode indicates the shaking of the ground 300 due to an earthquake.

[0039] If the magnitude of the detection signal from the vibration sensor 12 does not exceed the thresholds TH1 and TH2, the control device 16 keeps the control valve 15 closed, thereby maintaining the state in which the superstructure 100 is supported on the artificial ground 200. When the magnitude of the detection signal from the vibration sensor 12 exceeds the threshold values ​​TH1 and TH2, the control device 16 switches the control valve 15 to an open state.

[0040] 6(b), the control device 16 detects the acceleration (vibration) of the superstructure 100 caused by the first arriving vibration (e.g., P wave) at time t10. Thereafter, the control device 16 determines that the magnitude of the detection signal from the vibration sensor 12 exceeds the threshold value TH2 at time t11, and switches the control signal of the control valve 15 from the OFF level to the ON level. When the control signal is switched to an on level, the control valve 15 is opened, and the compressed air stored in the air tank 13 is supplied into the air chamber 11 through the air supply pipe 14 . Furthermore, when the magnitude of the detection signal from the vibration sensor 12 exceeds the threshold value TH2, the control device 16 switches the mode from the normal mode to the determination mode.

[0041] When air is supplied into the air chamber 11, the air chamber 11 expands, and the superstructure 100 rises above the artificial ground 200. Vibrations from the artificial ground 200 (ground 300) are less likely to be transmitted to the superstructure 100 that has risen above the artificial ground 200. Since the vibration sensor 12 is installed on the superstructure 100, even if the magnitude of shaking of the artificial ground 200 is the same before and after the lift-off, the amplitude of the detection signal from the vibration sensor 12 after the lift-off will be sufficiently smaller than that before the lift-off (see Figure 7(b)).

[0042] The control device 16 supplies air to the air chamber 11 in an amount that causes the upper structure 100 to rise to the judgment height H12. In this embodiment, the opening time (T11) of the control valve 15 required to raise the upper structure 100 above the artificial ground 200 to the judgment height H12 is obtained in advance through experiments, etc., and stored in the memory 16b of the control device 16. As shown in FIG. 7(b), the control device 16 keeps the control signal at an on level and maintains the open state of the control valve 15 from time t11 until the open time T11 has elapsed. 7(a), the upper structure 100 reaches the judgment height H12 at time t12 after the opening time T11 has elapsed. The control device 16 turns the control signal to the OFF level at time t12. Accordingly, the control valve 15 is switched to the closed state, and the supply of air from the air tank 13 to the air chamber 11 is stopped.

[0043] The volume of the air chamber 11 gradually decreases due to the weight of the superstructure 100. In other words, the superstructure 100 descends due to its own weight toward the artificial ground 200 at a speed that is sufficiently slower than when it rose up. As shown in FIG. 8(b), the control device 16 monitors the detection signal from the vibration sensor 12 while the upper structure 100 is lowering, and determines whether the magnitude of the detection signal from the vibration sensor 12 exceeds the threshold values ​​TH1 and TH2. As described above, since the upper structure 100 is rising, the shaking of the ground 300 must be greater than that at time t11 in order for the magnitude of the detection signal to exceed the thresholds TH1 and TH2.

[0044] In the example of FIG. 8(b), the magnitude of the detection signal changes over a period T12 from time t13 to time t14, and it can be seen that a second vibration (for example, an S wave) has arrived. However, at time T12, the detection signal does not exceed the thresholds TH1 and TH2, so the control device 16 keeps the control valve 15 closed, and as a result, the upper structure 100 continues to descend slowly.

[0045] In the judgment mode, the control device 16 monitors the detection signal (floating height detection information) from the proximity sensor 17 and acquires the floating height of the upper structure 100. Then, when the control device 16 determines that the floating height of the upper structure 100 has become equal to or less than a specified landing judgment height, it determines that the condition for transitioning to the normal mode is met and sets the normal mode. For example, when the detection signal from the proximity sensor 17 becomes equal to or lower than the landing judgment level, the control device 16 determines that the floating height of the upper structure 100 becomes equal to or lower than the specified landing judgment height.

[0046] In the example of FIG. 8(b), the control device 16 determines that the flying height of the upper structure 100 has become equal to or lower than the landing height at time t15, and sets the normal mode. The condition for transitioning to the normal mode is not limited to the above example. For example, the condition for transitioning to the normal mode may be that the time elapsed since the supply of air to the air chamber 11 was stopped (time t12) is equal to or greater than the landing determination time.

[0047] In the example of Figure 9(b), it can be seen that the second vibration (e.g., S wave) arrives at time t21. At time t21, the superstructure 100 is floating above the artificial ground 200, and therefore it can be seen that the second vibration is sufficiently larger than the vibration that arrived earlier (e.g., P wave). At time t22, the control device 16 determines that the magnitude of the vibration has exceeded the threshold value TH2, and sets the control signal of the control valve 15 to an on level to supply air to the air chamber 11, causing the upper structure 100 to levitate again.

[0048] The control device 16 supplies the air chamber 11 with a differential air volume obtained by subtracting the air volume required to lift the upper structure 100 to the judgment height H12 from the air volume required to lift the upper structure 100 to the specified height H1. In this embodiment, the amount of air supplied to the air chamber 11 is adjusted by the opening time of the control valve 15 . For example, suppose the opening time of the control valve 15 required to raise the superstructure 100 supported on the artificial ground 200 to the specified height H1 is T1 (see Figure 2(b)), and the opening time of the control valve 15 required to raise the superstructure 100 supported on the artificial ground 200 to the judgment height H12 is T11 (see Figure 7(b)). In this case, as shown in FIG. 9(b), the opening time T21 of the control valve 15 required to refloat the upper structure 100 is the opening time T1 minus the opening time T11.

[0049] This control prevents the floating height of the upper structure 100 from exceeding the specified height H1, thereby preventing the inconvenience of raising the upper structure 100 more than necessary, in other words, preventing the inconvenience of supplying air unnecessarily to the air chamber 11. The opening time T1 of the control valve 15 required to lift the upper structure 100 to the specified height H1 is obtained in advance by experiment or the like, and is stored in the memory 16b of the control device 16.

[0050] 9(a) and 9(b), the upper structure 100 reaches the re-floating height H23 at time t23 after the release time T21 has elapsed. The control device 16 turns the control signal to the OFF level at time t23. Accordingly, the control valve 15 is switched to the closed state, and the supply of air from the air tank 13 to the air chamber 11 is stopped. Once the upper structure 100 reaches the re-floating height H23, it slowly descends due to its own weight. That is, the air chamber 11 slowly contracts due to the weight of the upper structure 100. During the levitation, vibrations of the ground 300 are not easily transmitted to the upper structure 100, so the upper structure 100 can be protected from earthquake vibrations.

[0051] In this example, the control device 16 also monitors the detection signal from the proximity sensor 17, and when it determines that the levitation height of the upper structure 100 has become equal to or lower than the landing judgment height, it sets the normal mode, assuming that the conditions for transitioning to the normal mode have been met. In the example of FIG. 9(b), the control device 16 determines that the flying height of the upper structure 100 has become equal to or lower than the landing judgment height at time t24, and sets the normal mode.

[0052] <Summary of operation examples> In the seismic isolation system 1 of this embodiment, when the detection signal of the vibration sensor 12 indicates seismic motion in the normal mode that is set under normal circumstances, the control device 16 controls the control valve 15 to supply air to the air chamber 11, causing the upper structure 100 to rise to a judgment height H12 that is lower than the specified height H1, and transitioning to the judgment mode. In the judgment mode, when the detection signal of the vibration sensor 12 indicates seismic motion, the control device 16 controls the control valve 15 to supply air to the air chamber 11, causing the upper structure 100 to refloat to a refloating height H23 that is below the specified height H1. On the other hand, if the detection signal of the vibration sensor 12 does not indicate seismic motion in the judgment mode, the upper structure 100 will slowly descend under its own weight and be supported on the artificial ground 200, and the control device 16 will switch from the judgment mode to the normal mode. In this case, the upper structure 100 will not be re-floated, so the consumption of air for re-floating can be reduced.

[0053] <Processing flow in Seismic Isolation System 1> Next, the flow of processing in the seismic isolation system 1 will be described. FIG. 10 is a flowchart showing the common control of the seismic isolation system 1, FIG. 11 is a flowchart showing the control of the seismic isolation system 1 in the normal mode, and FIG. 12 is a flowchart showing the control of the seismic isolation system 1 in the determination mode. When the operation of the seismic isolation system 1 starts, the control device 16 sets the normal mode (S1). Next, the control device 16 determines whether or not there is a power outage (S2), and if there is a power outage (S2, Yes), sets the battery-powered mode (S3). In the battery-powered mode, the control device 16, the control valve 15, and the sensors 12, 17, and 18 operate using the electrical energy stored in the storage battery 21.

[0054] If there is no power outage (S2, No), the control device 16 sets the AC drive mode (S4). In the AC drive mode, the control device 16, the control valve 15, and the sensors 12, 17, and 18 are operated by commercial power, and the pressure in the air tank 13 is increased by the compressor 19. If the control device 16 determines that the mode is AC drive mode (S5, Yes), it acquires a detection signal from the pressure sensor 18 (S6), and if the pressure in the air tank 13 has dropped (S7, Yes), it controls the compressor 19 via the control relay 20 to increase the pressure in the air tank 13 (S8).

[0055] The control device 16 acquires a detection signal from the vibration sensor 12 (S9), and then determines whether the normal mode is set (S10). If the normal mode is set (S10, Yes), the control device 16 proceeds to step S11 in FIG. 11 and checks whether the control valve 15 is closed. If the control valve 15 is in the closed state (S11, Yes), the control device 16 determines whether or not an earthquake has been detected based on the detection signal from the vibration sensor 12 (S12). If the control device 16 detects earthquake motion (S12, Yes), it opens the control valve 15 (S13) and sets the determination mode (S14). On the other hand, if the control device 16 does not detect earthquake motion (S12, No), it keeps the control valve 15 closed.

[0056] On the other hand, if the control valve 15 is opened in step S11 (S11, No), the control device 16 determines whether or not a first specified time has elapsed since the control valve 15 was opened (S15). The first specified time is the opening time of the control valve 15 required to lift the upper structure 100 to the judgment height H12, and corresponds to the opening time T11 (see FIG. 7(b)) in the above-described operation example. If the control device 16 determines that the first specified time has elapsed since the control valve 15 was opened (S15, Yes), it switches the control valve 15 to a closed state (S16). On the other hand, if the control device 16 determines that the first specified time has not elapsed since the control valve 15 was opened (S15, No), it maintains the control valve 15 in an open state.

[0057] Next, the control device 16 determines whether or not an operation to end the operation of the seismic isolation system 1 has been performed (S17), and if an operation to end the operation has been performed (S17, Yes), ends the series of processes. On the other hand, if the control device 16 determines that the operation to end the operation has not been performed (S17, No), the process proceeds to step S2 in FIG. 10, and the series of processes are repeatedly executed.

[0058] If the determination mode is set in step S10 of FIG. 10, the control device 16 proceeds to step S21 of FIG. 12 to check whether the control valve 15 is in a closed state. If the control valve 15 is in the closed state (S21, Yes), the control device 16 determines whether or not an earthquake has been detected based on the detection signal from the vibration sensor 12 (S22). If the control device 16 detects an earthquake (Yes in S22), it opens the control valve 15 (S23).

[0059] On the other hand, if the control device 16 does not detect earthquake motion (S22, No), it keeps the control valve 15 closed and determines whether the condition for transitioning to the normal mode is met (S24). For example, the control device 16 acquires levitation height information from the proximity sensor 17 and determines that the condition for transitioning to the normal mode is met when the levitation height information becomes equal to or less than the landing judgment height. Alternatively, the control device 16 may determine that the condition for transitioning to the normal mode is met when the time elapsed since the supply of air to the air chamber 11 was stopped at the time of re-levitation becomes equal to or greater than the landing judgment time. If the condition for transitioning to the normal mode is met (S24, Yes), the control device 16 sets the normal mode (S25). On the other hand, if the condition for transitioning to the normal mode is not met (S24, No), the control device 16 maintains the determination mode.

[0060] On the other hand, if the control valve 15 is opened in step S21 (S21, No), the control device 16 determines whether a second specified time has elapsed since the control valve 15 was opened (S26). The second specified time is the opening time of the control valve 15 required to lift the upper structure 100 to the refloating height H23. As in the above-described operation example, if the release time for raising the superstructure 100 above the artificial ground 200 to the specified height H1 is T1 and the release time for raising the superstructure 100 above the artificial ground 200 to the judgment height H12 is T11, the second specified time (i.e., release time T21) is the difference between the release time T1 and the release time T11. If the control device 16 determines that the second specified time has elapsed since the control valve 15 was opened (S16, Yes), it switches the control valve 15 to a closed state (S27). On the other hand, if the control device 16 determines that the second specified time has not elapsed since the control valve 15 was opened (S26, No), it maintains the open state of the control valve 15.

[0061] Next, the control device 16 determines whether or not an operation to end the operation of the seismic isolation system 1 has been performed (S28), and if an operation to end the operation has been performed (S28, Yes), ends the series of processes. On the other hand, if the control device 16 determines that the operation to end the operation has not been performed (S28, No), the control device 16 proceeds to step S2 in FIG. 10 and repeatedly executes a series of processes.

[0062] <Modification> In the above embodiment, the air chamber 11 is configured by the upper surface 200a of the artificial ground 200, the bottom surface 111a of the upper foundation 110, and the sealing member 130, but is not limited to this configuration. For example, an air bearing (air bag) may be provided instead of the above configuration.

[0063] In the judgment mode, with regard to the magnitude of the seismic motion used to determine whether or not to re-float the upper structure 100, in the above-described embodiment, the magnitude of the seismic motion in the judgment mode was greater than the magnitude of the seismic motion in the normal mode, but this configuration is not limited to this. For example, the magnitude of the earthquake motion at the time of determination in the determination mode may be the same as the magnitude of the earthquake motion at the time of determination in the normal mode.

[0064] Regarding the amount of air supplied to the air chamber 11, in the above-described embodiment, the amount of air supplied to the air chamber 11 at the time of re-floating is set to the differential air amount obtained by subtracting the amount of air required to float the upper structure 100 on the artificial ground 200 to the specified height H1 from the amount of air required to float the upper structure 100 on the artificial ground 200 to the judgment height H12, but this configuration is not limited to this. For example, the amount of air supplied to the air chamber 11 at the time of re-surfacing and the amount of air at the time of the judgment of the ascent may be determined separately, or the amount of air at the time of re-surfacing may be set to the same as the amount of air at the time of the judgment of the ascent.

[0065] Regarding the threshold values ​​TH1 and TH2, in the above-described embodiment, the same threshold values ​​TH1 and TH2 are used in both the normal mode and the determination mode, but the present invention is not limited to this configuration. For example, the threshold values ​​TH1 and TH2 in the determination mode may be set to values ​​different from the threshold values ​​TH1 and TH2 in the normal mode.

[0066] [Summary of embodiments, actions, and effects of the present invention] <First embodiment> The seismic isolation system 1 according to this embodiment comprises an air chamber 11 that is provided between a superstructure 100 and an artificial ground 200 that supports the superstructure 100, expands when supplied with air to raise the superstructure 100 above the artificial ground 200, and then contracts under the weight of the superstructure 100 after expansion to lower the superstructure 100, an air tank 13 that stores compressed air, a control valve 15 that is provided in an air supply pipe 14 that airtightly connects the air chamber 11 and the air tank 13 and whose open / close state is controlled, a vibration sensor 12 that detects vibrations, and a control valve 15 that controls the open / close state based on a detection signal from the vibration sensor 12. and a control device 16 that controls the control valve 15 by supplying air to the air chamber 11 when the detection signal of the vibration sensor 12 indicates seismic motion in a normal mode that is set during normal times, and the control device 16 controls the control valve 15 to supply air to the air chamber 11, causing the upper structure 100 to levitate to a judgment height H12 that is lower than the specified height H1 and transitioning to a judgment mode, and when the detection signal of the vibration sensor 12 indicates seismic motion in the judgment mode, the control device 16 controls the control valve 15 to supply air to the air chamber 11, causing the upper structure 100 to refloat to a height (refloating height H23) that is lower than the specified height H1.

[0067] In the seismic isolation system 1 according to this embodiment, when earthquake motion is detected during normal mode, the upper structure 100 is raised to a judgment height H12. Because this judgment height H12 is lower than the specified height H1, the amount of air supplied to the air chamber 11 can be less than when the upper structure 100 is raised to the specified height H1. When the upper structure 100 is raised to the judgment height H12, it switches to judgment mode. If seismic motion is detected during judgment mode, the upper structure 100 is re-floated, thereby protecting the upper structure 100 from seismic motion. On the other hand, if no seismic motion is detected during judgment mode, the upper structure is not re-floated, thereby reducing the consumption of air for re-floating.

[0068] <Second embodiment> In the seismic isolation system 1 of this embodiment, the magnitude of the seismic motion used to determine whether or not to re-float the upper structure 100 in the judgment mode is larger than the magnitude of the seismic motion used to determine whether or not to re-float the upper structure 100 to the judgment height H12 in the normal mode. In the seismic isolation system 1 according to this embodiment, in the judgment mode, if the system receives an earthquake motion greater than the earthquake motion that triggered the upper structure 100 to be raised to the judgment height H12, the upper structure 100 is raised again. Therefore, unnecessary re-raising of the upper structure 100 can be reliably prevented.

[0069] <Third embodiment> In the seismic isolation system 1 of this embodiment, the amount of air supplied to the air chamber 11 when the upper structure 100 is re-floated is characterized by being greater than the amount of air required to lift the upper structure 100 above the artificial ground 200 to the judgment height H12. In the seismic isolation system 1 according to this embodiment, the amount of air supplied during the judgment of levitation can be saved, and the upper structure 100 can be levitated to a sufficient height during re-levitation.

[0070] <Fourth embodiment> In the seismic isolation system 1 according to this embodiment, the amount of air supplied to the air chamber 11 when the superstructure 100 is re-floated is a differential air amount obtained by subtracting the amount of air required to lift the superstructure 100 on the artificial ground 200 to the judgment height H12 from the amount of air required to lift the superstructure 100 on the artificial ground 200 to the specified height H1. In the seismic isolation system 1 according to this embodiment, air can be supplied to the air chamber 11 without waste when the upper structure 100 is re-floated.

[0071] <Fifth embodiment> The seismic isolation system 1 of this embodiment is characterized in that it is equipped with a storage battery 21 that is charged by a commercial power source, the air tank 13 has compressed air whose pressure is increased by a compressor 19 that is powered by a commercial power source, and the control device 16, control valve 15, and vibration sensor 12 operate using the storage battery 21 when the commercial power source is unavailable. In the seismic isolation system 1 according to this embodiment, the compressed air stored in the air tank 13 can be used efficiently in a situation where the proprietary power source cannot be used and the pressure of the compressed air cannot be increased.

[0072] <Sixth embodiment> The seismic isolation system 1 according to this embodiment is provided with a proximity sensor 17 that detects the floating height of the upper structure 100 above the artificial ground 200, and the control device 16 monitors whether the condition for transitioning to the normal mode is met in the judgment mode, and transitions to the normal mode when the transition condition is met, and the condition for transitioning to the normal mode is when the detection signal from the vibration sensor 12 does not indicate seismic movement even when the floating height of the upper structure 100 falls below a predetermined judgment height. In the seismic isolation system 1 according to this embodiment, switching from the determination mode to the normal mode can be performed reliably. [Explanation of symbols]

[0073] 1...Seismic isolation system, 11...Air chamber, 12...Vibration sensor, 12A...Vibration detection means, 13...Air tank, 14...Air supply pipe (communication path), 15...Control valve, 16...Control device, 16A...Control means, 17...Proximity sensor, 17A...Floating height detection means, 18...Pressure sensor, 19...Compressor, 20...Control relay, 21...Storage battery, 22...Communication pipe, 100...Upper structure, 110...Upper foundation, 11 1...foundation body, 111a...bottom surface of foundation body, 112...foundation wall portion, 113...insertion hole, 120...structure body, 121...peripheral wall, 122...floor, 130...sealing member, 131...mounting frame body, 132...movable plate piece, 132a...lower edge of movable plate piece, 200...artificial ground, 200a...upper surface of artificial ground, 300...ground, H1...specified height, H12...determination height, H23...re-floating height, TH1...threshold, TH2...threshold

Claims

1. an air chamber provided between the superstructure and a support part that supports the superstructure, inflating when supplied with air to lift the superstructure off the support part, and contracting after inflation due to the weight of the superstructure to lower the superstructure; an air tank for storing compressed air; a control valve that is provided in a communication path that airtightly communicates between the air chamber and the air tank and whose open / close state is controlled; vibration detection means for detecting vibration; a control means for controlling the control valve based on vibration detection information from the vibration detection means, The control means When the vibration detection information indicates seismic motion in a normal mode that is set during normal times, the control valve is controlled to supply air to the air chamber, and the upper structure is raised to a judgment height that is lower than a specified height, thereby transitioning to a judgment mode; A seismic isolation system characterized in that when the vibration detection information indicates seismic motion in the judgment mode, the control valve is controlled to supply air to the air chamber, thereby re-floating the upper structure to a height below the specified height.

2. The seismic isolation system described in claim 1, characterized in that the magnitude of the seismic motion used to determine whether or not to re-float the upper structure in the judgment mode is greater than the magnitude of the seismic motion used to determine whether or not to re-float the upper structure to the judgment height in the normal mode.

3. The seismic isolation system described in claim 1, characterized in that the amount of air supplied to the air chamber when the upper structure is re-floated is greater than the amount of air required to lift the upper structure on the support portion to the judgment height.

4. The seismic isolation system described in claim 1, characterized in that the amount of air supplied to the air chamber when the upper structure is re-floated is the differential air amount obtained by subtracting the amount of air required to lift the upper structure on the support part to the judgment height from the amount of air required to lift the upper structure on the support part to the specified height.

5. Equipped with a storage battery that is charged by a commercial power source, The air tank has a compressor that is powered by the commercial power source and increases the pressure of the compressed air, 2. The seismic isolation system according to claim 1, wherein the control means, the control valve, and the vibration detection means are operated by the storage battery when the commercial power source is unavailable.

6. a lift-up height detection means for detecting a lift-up height of the upper structure from the support portion, the control means monitors whether a condition for transitioning to the normal mode is satisfied in the determination mode, and transitions to the normal mode when the condition for transitioning is satisfied; 2. The seismic isolation system according to claim 1, wherein the transition condition is when the vibration detection information does not indicate seismic motion even when the floating height falls below a predetermined judgment height.

Images