JPH11247928A - Base isolation device having ultra-long cycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation device having an ultra-long cycle by constituting the base isolation device of an ultra-low frictional sliding bearing to support a structure, a fuse mechanism having a restoring force mechanism and starting a base isolation function by seismic force of a certain magnitude and a former position returning mechanism. SOLUTION: In a complex unit 3, when a wire 11 is pulled according to displacement of a structure 30 receiving seismic force, tensile force of the wire 11 acts as the rotation moment to a drum 10. When torque of the drum 10 by this rotation moment exceeds restraining force of the drum 10 by a lock pin 17, the lock pin 17 is pushed out of the recessed part of the drum 10, so that rotation of the drum 10 starts. That is, a fuse mechanism allows a movement of the structure 30 only to a big earthquake not less than a preset value by preventing excessive swinging of the structure 30 when seismic force and a wind load applied to the structure 30 are not more than the preset value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a next-generation ultra-long-period seismic isolation device in which the response cycle (seismic isolation cycle) of a structure to an earthquake is very long, for example, about 10 seconds.

[0002]

2. Description of the Related Art It is understood from the acceleration response spectrum shown in FIG. 11, for example, that the longer the predominant period (seismic isolation period) of the seismic isolation structure, the greater the effect. In FIG. 11, the arc a represents the current seismic isolation cycle (3 to 4 seconds), and the arc b represents the next-generation seismic isolation cycle targeted by the present invention (about 10 seconds). By the way, the conventional seismic isolation device using laminated rubber is the mainstream. For the purpose of solving the limit of the seismic isolation cycle of the laminated rubber, the seismic isolation device described in Japanese Patent Application Laid-Open No.
The vertical load of the building is supported by both elastic sliding bearings and laminated rubber bearings, and the seismic isolation cycle is extended. The seismic isolation device described in Japanese Patent Application Laid-Open No. 2-153139 is provided with a sealed space sealed with a membrane of a sliding bearing for supporting a structure, and in the event of an earthquake, pressurized fluid is sealed in the sealed space, and this pressure fluid is used. This structure is to reduce the apparent coefficient of friction by sharing the load support of the structure. In the hydraulic seismic isolation device described in Japanese Patent Application Laid-Open No. 5-10387, a hydraulic chamber is provided between a sliding surface formed on a base and a bottom surface of a structure supported on the base, and the hydraulic chamber is supplied to the hydraulic chamber. The structure is supported by the pressurized water, and the frictional resistance with the sliding surface is extremely small.

[0003]

The seismic isolation device using the above laminated rubber is characterized in that its seismic isolation period is proportional to the surface pressure supporting the structure and the height of the laminated rubber itself. It is understood as shown in the attached table "Formula 1". The amount of horizontal deformation of the laminated rubber during an earthquake increases in proportion to the length of the seismic isolation period.However, as a means of extending the period, if the height of the laminated rubber is increased or the surface pressure is increased, the laminated The horizontal deformation ability of rubber becomes unstable and naturally has its limitations. After all,
It is considered that the limit of the seismic isolation cycle of laminated rubber is about 5 seconds.

[0004]

(Equation 1)

The above seismic isolation device attempts to solve the problem of the laminated rubber, but the sliding material of the elastic sliding bearing is made of tetrafluoroethylene resin, and has a relatively large friction coefficient (friction coefficient μ = 0.1), and a dramatic improvement in the seismic isolation effect cannot be expected. The above seismic isolation device reduces the apparent friction coefficient with the pressure fluid sealed in the seal space for the purpose of reducing the friction coefficient of the sliding bearing, but means for sealing the pressure fluid into the seal space during an earthquake As such, electro-hydraulic control, which constantly monitors for an earthquake that cannot be known when it occurs, is adopted, and there is concern over long-term reliability, and maintenance costs become extremely high.

Although the above-mentioned seismic isolation device solves the above-mentioned problems relating to the sliding bearing, it is impossible to predict how far a structure having a low coefficient of friction will move when an earthquake occurs using only this seismic isolation device. It is. There is also a problem that the structure easily moves due to the wind load. Therefore, it is an object of the present invention to achieve a very long seismic isolation period, yet have no problem in long-term reliability, do not require much maintenance cost, and limit the range in which structures move. It is an object of the present invention to provide an ultra-long-period seismic isolation device that has a configuration that can predict the position of the structure and has no problem that the structure easily moves due to a wind load, and that contributes to the realization of a next-generation seismic isolation structure.

[0007]

According to a first aspect of the present invention, there is provided an ultra-long-period seismic isolator according to the first aspect of the present invention. It is characterized by comprising a force mechanism, a fuse mechanism for starting a seismic isolation function with a certain magnitude of seismic force, and an original position return mechanism.

According to a second aspect of the present invention, the original position return mechanism in the very long-period seismic isolation device according to the first aspect is provided with a drum that rotates in a horizontal direction on either the ground or the structure. The other end of a fixed length wire fixed at one end to a structure or the ground is wound around and connected to the drum, and a driving device such as an electric motor or a hydraulic motor is connected to a rotating shaft of the drum, and after the earthquake, It is characterized in that it is configured to rotate in a direction to wind up a loose wire.

According to a third aspect of the present invention, the fuse mechanism in the very long-period seismic isolation device according to the first or second aspect,
A concave portion is provided on the horizontal surface side of the drum, and a lock pin that fits into the concave portion is provided on the structure or ground side so as to be able to enter and exit in the vertical direction, so that the fitted state is maintained until a certain amount of rotational force. It is characterized by being pushed behind by a certain amount of force.

According to a fourth aspect of the present invention, there is provided an ultra-long period seismic isolation device according to the second aspect, wherein a drum constituting a home position return mechanism and a wire wound and connected to the drum are connected to the drum. A plurality of units are provided in which a combination of a left-handed set in which the wire is wound and connected to the left and a right-handed set in which the wire is wound and connected to the drum as one unit.

According to a fifth aspect of the present invention, there is provided an ultra-long-period seismic isolation device according to the second or fourth aspect, wherein the drum constituting the original position return mechanism and the wire wound and connected to the drum are connected. In addition, there is provided an entrainment preventing means for always pulling the wire loosened after the earthquake in a direction in which the wire is separated from the drum.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The very long-period seismic isolation device according to the first aspect of the present invention is, as shown in FIG. Friction sliding bearing 1, laminated rubber 2 adopted as a restoring force mechanism,
It is composed of a fuse mechanism for starting a seismic isolation function with a certain magnitude of seismic force, and a composite unit 3 of an original position return mechanism. FIG. 2 illustrates a method of supporting the structure 30 by the extremely low friction sliding bearing 1 and the laminated rubber 2. Reference numeral 5 in the figure is the ground.

FIG. 1 does not show a specific structure of the laminated rubber 2 employed as a restoring force mechanism in the seismic isolation device having a very long period, but the laminated rubber and the damper, which are already known and well known, are omitted. It is possible to selectively use a combined configuration, a configuration of a laminated rubber using high-damping rubber alone, or the like. The movement range of the structure 30 in the earthquake ground is limited by the function of the restoring force mechanism. A circle 15 in FIG. 4 illustrates the size of the movement range.

The very low-friction sliding bearing 1 for supporting the structure is not intended to exclude the use of sliding bearings or other known sliding bearings cited in the section of the prior art. The exemplified ones can be suitably used. FIG. 3 shows a configuration of a static pressure bearing in which a stainless steel plate and a fluid are sealed. Ram 1a which receives vertical load of structure 3
The cylinder tube 1b has a seal ring 1c
It is installed watertight. A sliding plate 4 made of a stainless steel plate on which the ram 1a is mounted is laid on the surface of the ground 5 in a size that covers the moving range of the ram 1a.
The pressure oil supplied to the supply port 1d provided in the cylinder tube 1b passes through the oil passage 1e of the ram 1a and reaches the hydraulic surface 6 on the lower surface of the ram. The hydraulic surface 6 has a gap of about several millimeters, and is tightly sealed by an inner seal 1f, an outer seal 1g, and a pad 1h therebetween provided concentrically on the lower surface of the cylinder tube 1b. The oil that has leaked to the outer seal 1g due to sliding movement or the like is also discharged from a drain port 1k provided in the cylinder tube 1b. The hydraulic pressure on the hydraulic surface 6 is 70-100 kg / cm ² . In short, the ram 1a supporting the structure 30 moves with extremely low frictional resistance in the range of the frictional resistance of the oil on the hydraulic surface 6.

Next, the configuration of the composite unit 3 of the fuse mechanism and the original position return mechanism in the seismic isolation device having an extremely long cycle illustrated in FIG. 1 is shown as an embodiment in FIGS. FIG.
As shown in (1), a drum 10 that rotates in the horizontal direction is installed on the ground 5 side (or on the side of the structure 30). In FIG. 4, one end of the ground 10 is connected to the structure 30 (or vice versa) in a direction that divides the horizontal plane into four parts.
In some cases. The other ends of four wires 11 (or tension cables, the same applies hereinafter) of a fixed length fixed to the drum 10 are wound around and connected to the drum 10 in a common tangential direction. Incidentally, the size of the drum 10 is such that the inner diameter of the wire winding groove is 150 cm and the width and thickness are about 45 cm. The length of the four wires 11 is equal, and as shown in FIG.
When the fixed point 14 to 0 is located at each vertex of the square, the length of one side of the square is about 6 m in length and length. Further, in order to facilitate the winding of the wire 11 arranged at a certain angle as shown in FIG. 5, the side wall of the wire winding groove of the drum 10 has a slope equal to or slightly larger than the slope angle of the wire 11. It is formed at an angle.

The connecting position between the drum 10 and the wire 11 may be a contact point S between the cable 11 arranged in the tangential direction as described above and the circumference of the drum 10 or an arbitrary size in the circumferential direction from the position of the contact point S. The position may be any position as long as the position has advanced to the arc angle (the amount of rotation of the drum 10 is determined by the size of the arc angle). If the arc angle is large and there is concern about interference with the adjacent wire, a spiral partition wall is formed in the wire winding groove on the outer peripheral surface of the drum 10 so that the winding position (groove) of each wire is changed. It is good to make the configuration that distinguishes.

As shown in FIG. 6, a connecting means for connecting the drum 10 to the wire 11 forms a recess 10b in the bottom surface of the wire winding groove 10a of the drum 10, and the recess 10b
In the inside, the tail 12 at the end of the wire is freely connected with the stopper pin 13. As a result of the drum 10 on the ground 5 side being connected to the wire 11 having one end connected to the structure 3 in this manner,
After all, it is equivalent to the ground 5 and the structure 30 being connected by the wire 11.

The fuse mechanism is configured as follows. As shown in FIG. 7, the horizontal surface side of the drum 10
That is, in the example of FIG. 5, a substantially trapezoidal recess 1 having an inclined surface of about 45 degrees before and after in the rotation direction is provided on a lower surface side facing the ground 5 and having a rotation radius as large as possible (position closer to the outer periphery).
6 are provided. On the other hand, on the side of the ground 5, a lock pin 17 having a tip portion sharpened in a trapezoidal shape having substantially the same shape and the same size as the concave portion 16 is provided so as to be able to enter and exit in the vertical direction. The spring 1 exerts a force for stopping the rotation of the drum 10 while maintaining the fitted state in the concave portion 16 up to a certain amount of rotational force.
8, the lock pin 17 is pushed behind.
Described invention).

In the composite unit 3 having the above-described structure, when the wire 11 is pulled due to the displacement of the structure 30 subjected to the seismic force, the tension of the wire 11 acts as a rotational moment with respect to the drum 10. The rotational force of the drum 10 due to this rotational moment is applied to the lock pin 17.
At this point, the lock pin 17 is pushed out of the concave portion 16 of the drum 10 and rotation of the drum 10 starts. That is, when the seismic force and wind load received by the structure 30 are equal to or less than the set values,
The structure 30 is prevented from shaking unnecessarily, and the structure 30 is allowed to move only for a large earthquake exceeding a set value.

The original position return mechanism in the seismic isolation device having a very long period is based on the configuration of a wire 11 of a fixed length arranged around the drum 10 and a lock pin 17 fitted into a concave portion 16 of the drum. The driving device 19 such as an electric motor or a hydraulic motor is connected to the rotating shaft of the drum 10 (FIG. 4). As described above, when the structure 30 receives an earthquake large enough to move, the wire 11 that has become loose after the earthquake causes the driving device 19 to rotate the drum 10 in the winding direction, and the drum 10 causes the wire 11 to rotate.
And the structure 3 is returned to the original position via the wire 11 (the invention according to claim 2). At the same time when the structure 30 returns to the original position, the lock pin 17 is fitted into the concave portion 16 of the drum 10 again, and the fuse mechanism itself is restored.

As described above, the original position return mechanism performs a return function as a rotational force by the rotation of the drum 10 and the tension of each wire 11 accompanying the rotation. Therefore, as shown in FIGS. 9 and 10, the composite unit 3 including the original position return mechanism connects the drum 10 with the wire 11 wound around and connected to the drum.
Is a combination of a left-handed set 3A in which is wound and connected in a tangential direction common to the left-handed winding, and a right-handed set 3B in which the wire 11 is wound and connected in a tangential direction common to the right-handed winding on the drum as one unit. A unit is installed (the invention according to claim 4). When a plurality of units are installed in this manner, the same operation and effect as described above can be expected even if the number of wires 11 wound around one drum 10 is at least one.

Further, in the above-described seismic isolation device having a very long cycle, the relationship between the drum 10 constituting the original position return mechanism and the wire 11 wound and connected to the drum reduces the loosening of the wire 11 after the earthquake. Entrainment preventing means 20 that always pulls the wire away from the drum
Is provided (the invention according to claim 5). The illustrated entanglement preventing means 20 is formed of a rod-like body having a strong spring property, and is always in contact with the wire 11. When the tension of the wire 11 is slightly loosened as the drum 10 rotates, it is moved away from the drum 10 as shown in FIG. 8. .

[0023]

[Effects of the present invention] The seismic isolation device having a very long period according to the present invention achieves a very long seismic isolation period, and is also excellent in long-term reliability and does not require much maintenance cost. Further, since the range in which the structure moves is determined and can be predicted, and there is no problem that the structure easily moves due to the wind load, it contributes to the realization of the next-generation seismic isolation structure.

[Brief description of the drawings]

FIG. 1 is a plan view of a seismic isolation device according to the present invention.

FIG. 2 is a view taken in the direction of arrows YY in FIG.

FIG. 3 is a sectional view of a hydrostatic bearing.

FIG. 4 is a plan view of a composite unit including a fuse mechanism, a home position return mechanism, and a movement range limiting mechanism.

FIG. 5 is an elevation view of the composite unit.

FIG. 6 is a partial view showing connection between a drum and a wire.

FIG. 7 is a detailed partial view of a fuse mechanism.

FIG. 8 is a diagram illustrating the operation of the composite unit.

FIG. 9 is a plan layout view of the composite unit.

FIG. 10 is a plan layout view of the composite unit.

FIG. 11 is an acceleration response spectrum diagram of the seismic isolation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Very low friction sliding bearing 3 Composite unit 5 Ground 10 Drum 11 Wire 17 Lock pin (fuse mechanism) 19 Driving device (original position return mechanism) 30 Structure

Claims (5)

[Claims] An extremely low friction sliding bearing for supporting a structure;
An ultra-long-period seismic isolation device comprising a restoring force mechanism, a fuse mechanism for starting a seismic isolation function with a certain magnitude of seismic force, and an original position return mechanism. 2. The original position return mechanism includes a drum that rotates in a horizontal direction on either the ground or a structure,
The other end of a fixed length wire fixed at one end to a structure or the ground is wound around and connected to the drum, and a driving device such as an electric motor or a hydraulic motor is connected to a rotating shaft of the drum, and loosened after the earthquake. The ultra-long-period seismic isolation device according to claim 1, wherein the seismic isolation device is configured to rotate in a winding direction. 3. A fuse mechanism, wherein a concave portion is provided on a horizontal surface side of the drum, and a lock pin fitted in the concave portion is provided on a structure or ground side so as to be able to enter and exit in a vertical direction,
Up to a certain amount of rotational force, the back side is pushed with a constant amount of force so as to maintain the fitted state,
The super long period seismic isolation device according to claim 1 or 2. 4. A relationship between a drum constituting an original position return mechanism and a wire wound around and connected to the drum is: a left-handed set in which a wire is wound and connected to the drum in a left-handed manner; The ultra-long-period seismic isolation device according to claim 2, wherein a plurality of units are installed in such a manner that a combination with a right-handed set that is wound and connected to one unit is one unit. 5. In a relation between a drum constituting an original position return mechanism and a wire wound around and connected to the drum, there is provided an entrainment preventing means for always pulling the wire loosened after the earthquake in a direction away from the drum. The ultra-long period seismic isolation device according to claim 2, wherein the seismic isolation device is provided.