JP2001288930A - Seismically isolated structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seismically isolated structure which is constructed on the ground via a foundation, has a long natural vibration cycle with respect to the foundation of an upper structure, and can avoid transfer of large earthquake ground motion to the upper structure. SOLUTION: According to the seismically isolated structure, a vertical support mechanism 3 is set on the foundation 1 to support the upper structure 2. The vertical support mechanism 3 supports a vertical load via a spherical or a columnar rolling element mounted on a smooth support surface, to thereby accommodate horizontal movement of the upper structure. As a result, transfer of a large earthquake ground motion to the upper structure 2 is avoided. Further, a restoring-damping mechanism 4 formed of rubber as a main material is interposed between the foundation 1 and a footing beam 2a of the upper structure 2. The restoring-damping mechanism 4 need not support a vertical load, and therefore it can be formed of a material which is flexibly deformable, whereby natural period of the upper structure 2 can be elongated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure, such as a building or a civil engineering structure, constructed on a ground through a foundation, and particularly when large earthquake motion is transmitted from the ground to an upper structure during an earthquake. The present invention relates to a seismic isolation structure capable of avoiding.

[0002]

2. Description of the Related Art Japan is a country where earthquakes frequently occur, and buildings and civil engineering structures must be designed to withstand large earthquakes. For this reason, several design techniques for seismic ground motion have been proposed, one of which is a structure that prevents the energy of large seismic ground motion from being transmitted to the upper structure, that is, a seismic isolated structure.

[0003] The seismic isolation structure has the following basic functions:
It has the function of isolating seismic motion from being transmitted to the upper structure (isolate), the function of applying a restoring force to the upper structure (trigger), and the function of damping the vibration of the upper structure (damper). Things. The thing which has been embodied so far as having such a function is a thing which supports an upper structure through a laminated rubber or a friction slide bearing on a foundation in general, and an earthquake motion directly It is designed to avoid transmission to the structure.

A device using the above laminated rubber has the following structure.

An elastic bearing in which synthetic rubber such as neoprene rubber or the like and a reinforcing material are alternately laminated and adhered is mounted on a foundation, and an upper structure is constructed thereon. All vertical loads such as the weight of the upper structure are supported by the bearing made of the laminated rubber. In addition, a device that gives a restoring force and a damping of the vibration in the horizontal direction is used as necessary.

In such a structure, since the upper structure is supported via the laminated rubber, a relative displacement in the horizontal direction is allowed between the foundation and the upper structure due to the shear deformation of the laminated rubber, and a large earthquake motion is generated. Is not transmitted to the superstructure.

On the other hand, a seismic isolation structure using a friction slide bearing supports an upper structure via a bearing having a sliding surface made of fluororesin or the like. The structure behaves as a single body, but slides on the sliding surface with respect to large seismic motion, and large seismic motion is not transmitted to the upper structure.

[0008]

However, the conventional seismic isolation structure as described above has the following problems.

In general, the ideal of a seismic isolation structure is to make the natural period of the entire upper structure be infinite or a long period close to it. Can be. However, when the upper structure is supported using the laminated rubber, the hardness of the laminated rubber needs to be increased to some extent in order to support the total vertical load from the upper structure with the laminated rubber. Also, the bearing area must be increased. For this reason, the natural period of the upper structure cannot be increased, and at most 2-3
Seconds.

[0010] For this reason, the shearing force generated between the layers of the building during an earthquake becomes excessive, or a device for maintaining safety against overturning becomes necessary, which makes it difficult to increase the height of the building. There is.

Further, in the case of using a friction slide bearing, the structural system differs between when the sliding on the sliding surface occurs and when it does not occur. When the seismic motion is input, the structural system changes every moment, and the behavior is changed. It gets complicated. Therefore, there is a problem that analysis for confirming design and safety becomes difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object the purpose of having a long natural vibration cycle with respect to the foundation of an upper structure and transmitting large seismic motion to the upper structure. An object of the present invention is to provide a seismic isolation structure that can be effectively avoided and can be applied to low-rise to high-rise buildings.

[0013]

Means for Solving the Problems In order to solve the above problems, a seismic isolation structure according to a first aspect of the present invention comprises an upper structure between a foundation and an upper structure built thereon. A seismic isolation structure provided with a plurality of vertical support mechanisms for supporting vertical loads, wherein each of the plurality of vertical support mechanisms is fixed to a top surface of the foundation via a lower plate via a first single rail. A second rail member fixed to a lower surface of the upper structure via an upper plate so as to intersect at right angles with the first single rail member; A movable member provided at the intersection of the rail-shaped member and the second single rail-shaped member so as to be movable in the longitudinal direction of both rail-shaped members,
The movable body includes a lower movable body engaged with the first single rail-shaped member, and an upper movable body engaged with the second single rail-shaped member, Groove-shaped rolling formed between the groove-shaped rolling surface formed on the upper surface and side surface of one rail-shaped member and the lower movable body and on the upper surface and side surface of the second single rail-shaped member. A number of rolling elements are interposed between a surface and the upper movable body, and an upper surface of the lower movable body and a lower surface of the upper movable body are overlapped with each other.

In a preferred embodiment of the first invention, the upper surface of the first single rail member is formed linearly, and the lower surface of the second single rail member is formed linearly. You.

In a preferred embodiment of the first invention, a restoring and / or damping mechanism is provided between the foundation and the upper structure.

A seismic isolation structure according to a second invention is a seismic isolation structure having a vertical support mechanism for supporting a vertical load of an upper structure built on a foundation, wherein the vertical support mechanism comprises:
The first support plate is a lowermost layer, a second support plate is an intermediate layer, and a third support plate is an uppermost layer. The lower surface of the first support plate is fixed to a foundation, and the third support plate is fixed. The upper surface of the plate is fixed to the upper structure, and the upper surface of the first support plate has a plurality of first V-shaped cross sections extending in a first direction.
Are formed on the lower surface of the second support plate, and a plurality of first protrusions extending in the first direction and having a V-shaped cross section that engages with the first rail protrusions. A rail recess is formed, and a plurality of second rail protrusions having an inverted V-shaped cross section extending in a second direction perpendicular to the first direction are formed on an upper surface of the second support plate, A plurality of second rail recesses having a V-shaped cross-section extending in the second direction and engaging with the second rail protrusions are formed on a lower surface of the third support plate. Features.

In a preferred embodiment of the second invention, between the first rail projection and the first rail recess,
A large number of cylindrical rolling elements are provided so as to rollably engage with each other, and between the second rail projection and the second rail recess are also rollably engaged with each other. A number of cylindrical rolling elements are provided.

In a preferred embodiment of the second invention, a restoring and / or damping mechanism is provided between the foundation and the upper structure.

[0019]

According to the seismic isolation structure of the first aspect, when the foundation moves in the horizontal direction during an earthquake, the movable body slides along the first and second rail-shaped members in synchronization with the horizontal movement. ,
Even if ground motion in any direction is input to the foundation, it is possible to significantly reduce the ground motion transmitted to the upper structure, and to minimize the roll of the upper structure during an earthquake.

According to the seismic isolation structure of the second invention, when the foundation moves in the horizontal direction during an earthquake, the third support plate moves along the first and second rail-shaped convex portions in synchronization with the horizontal movement. Slides, even if ground motion in any direction in the horizontal plane is input to the foundation, it is possible to significantly reduce the ground motion transmitted to the upper structure, minimizing the roll of the upper structure during an earthquake Can be suppressed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing one embodiment of a seismic isolation structure according to the first invention.

In this seismic isolation structure, an upper structure 2 of a multilayer frame is supported on a foundation 1, and the lower ends of the columns of the upper structure 2 are supported by a vertical support mechanism 6 using a linear slide. Have been. In addition, a restoring / damping mechanism 7 is provided between the foundation beam 2a connecting the lower end of the column and the foundation 1 for applying a horizontal restoring force and damping the vibration of the upper structure 2.

FIG. 2 is a side view of the vertical support mechanism 6 used in the embodiment shown in FIG.

The vertical support mechanism 6 is a so-called linear slide, which is used in two layers so that the directions of movement are perpendicular to each other, and is a rail-shaped member 62 constituting a first rolling mechanism. Are fixed to the foundation 1 via the lower plate 61. A frame 63 is engaged so as to embrace the head of the rail-shaped member 62, and a large number of small steel balls 67 (rolling elements) are inserted between the frame 63 and the rail-shaped member 62. ing. When the steel balls 67 roll, the frame 6
Reference numeral 3 allows the rail-shaped member 62 to move in the axial direction with extremely small resistance.

On the other hand, the rail-shaped member 65 constituting the second rolling mechanism is fixed to the lower surface of the upper structure 2 via the upper plate 66, and the direction of its axis is the same as that of the first rolling mechanism. Is set in a direction perpendicular to the rail-shaped member 62.
The frame 64 is held so as to embrace the lower part of the rail-shaped member 65.
Are engaged, a large number of small steel balls 67 are inserted between the rail-shaped member 65 and the frame 64, and the frame 64 can be easily moved in the axial direction of the rail-shaped member 65. . Then, the frame 63 of the first rolling mechanism and the frame 64 of the second rolling mechanism are overlapped and fixed, and the rail-shaped member 62, the steel ball 67, and the frame of the first rolling mechanism described above. The vertical load of the upper structure 2 is supported by the foundation 1 via the frame body 63 of the second rolling mechanism, the steel ball 67, and the rail-shaped member 65.

Further, since the frame 64 and the frame 63 are engaged so as to embrace the heads of the rail-shaped members 65 and 62, the frame 64 and the frame 63 can also resist the lift acting on the upper structure 2. It also has the effect of preventing falls.

FIG. 3 is a schematic sectional view of the restoration / damping mechanism 7 used in the embodiment shown in FIG.

The restoration / damping mechanism 7 includes a lower plate 71 fixed to the foundation 1, an upper plate 73 fixed to the lower surface of the upper structure 2, and both ends joined to the upper plate 73 and the lower plate 71, respectively. The main part is constituted by a large number of steel rods 72, and the steel rods 72 are joined by being inserted into holes formed in the upper plate 73 and the lower plate 71. Further, a cylindrical peripheral wall 71a is formed on the peripheral edge of the lower plate 71, and has a container-like shape and is filled with a viscous fluid 74 inside.

In such a restoring / damping mechanism 7, when a relative displacement occurs between the upper structure 2 and the foundation 1, the steel rod 7
Bending deformation occurs in the upper structure 2
To the initial setting position. Further, the viscous fluid 74 is filled around the steel rod 72,
Due to the viscous resistance of the deformation of the upper structure 2, the energy of the seismic motion of the upper structure 2 is absorbed, and the vibration is attenuated.

FIGS. 4 and 5 show that a five-layered ramen structure is actually supported by a vertical support mechanism 6 as shown in FIG.
This shows the result of observation of actual seismic motion as having the restoration / damping mechanism 7 as shown in FIG.

FIG. 4 shows the recording of the vibration acceleration in the X direction, and FIG. 5 shows the recording of the vibration acceleration in the Y direction (both in the horizontal direction). This shows the result of observation at.

As can be seen from these figures, the upper structure 2
Is significantly smaller than that of the foundation 1, and only a small amount of the ground motion is transmitted from the foundation 1 to the upper structure 2, indicating that the structure has an excellent seismic isolation structure.

FIG. 6 is a front view and a side view of the vertical support mechanism of the seismic isolation structure according to the second invention.

The vertical support mechanism 8 supports the vertical load of the upper structure 2 via three support plates. The first support plate 82 in the lowermost layer is connected to the base 1 via the lower plate 81. Fixed on top. On the upper surface of the first support plate, two rail-shaped convex portions 82a having a mountain-shaped cross section are provided in parallel. A groove 83 having a V-shaped cross section is provided on the lower surface of the second support plate 83 at a position facing the rail-shaped convex portion 82a.
a is provided, and a number of small cylindrical rolling elements (rollers) 86 are interposed between the rail-shaped convex portion 82a and the inner surface of the groove 83a. As the rolling element 86 rolls, the first support plate 82 and the second support plate 83 relatively move in the axial direction of the rail-shaped convex portion 82a with extremely small force.

On the upper surface of the second support plate 83, a rail-shaped convex portion 82 provided on the upper surface of the first support plate 82 is provided.
A similar rail-shaped projection 83b is provided in a direction perpendicular to the direction of a. A groove 84a is provided on the lower surface of the third support plate 84 so as to face the rail-shaped projection 83b, and a cylindrical rolling element 86 is interposed between the rail-shaped projection 83b and the groove 84a. The second support plate 83 and the third support plate 8
Reference numeral 4 indicates that the first support plate 82 and the second support plate 83 can move relative to each other in a direction perpendicular to the direction of relative movement. The third support plate 84 is joined to the upper structure 2 via the upper plate 85, and the relative movement between these support plates allows the upper structure 2 to move in all directions in the horizontal plane. .

Therefore, even if a horizontal ground motion is input to the foundation 1, the ground motion transmitted to the upper structure 2 is reduced, and the safety of the upper structure 2 is maintained.

FIG. 7 is a front view and a side view showing another example of the vertical support mechanism shown in FIG.

The vertical support mechanism 9 uses two linear slides in the same manner as the vertical support mechanism 6 shown in FIG. 2, and is set so that the movable directions are perpendicular to each other. The first rail-shaped member 92 fixed to the base 1 via the lower plate 91 is curved so that the central portion is concave downward,
The second fixed to the lower surface of the upper structure 2 via the upper plate 96
The rail-shaped member 95 is curved so that its central portion is concave upward. And these rail-shaped members 92, 9
5 and a frame 9 joined by inserting a steel ball 97 (rolling element)
3, 94 move along the concave arc, and apply a restoring force to the initial setting position. As these frames 93, 94 move along the rail-shaped members 92, 95, the angles of the rolling surfaces change, and the two frames 93, 94 are joined via a ball seat 98.

With such a vertical support mechanism 9, it is possible to reduce the seismic motion transmitted to the upper structure 2 with respect to the horizontal seismic motion in any direction, and to make the rail-shaped members 92 and 95 possible.
Since the rolling surface is curved concavely, the weight of the upper structure 2 generates a restoring force to the initial setting position. Further, the vibration period of the vibration system thus formed is not affected by the mass of the upper structure 2, and the vibration period T of the structure can be easily made longer.

In a seismic isolation structure using the vertical support mechanism 9 as shown in FIG. 7, the upper structure 2 is slightly moved up and down by the relative movement of the foundation 1 and the upper structure 2 in the horizontal direction. Displace. For this reason, for example, FIG.
The following device is used.

In this damping mechanism 10, a lower plate 101 fixed to a foundation is formed in a container shape having a spherical bottom, and is filled with a viscous fluid 103. On the other hand, a circular plate 102 whose bottom surface is a convex spherical surface is supported by the upper structure 2 and is set at a position facing the bottom surface of the container-like lower plate 101 at an interval in a viscous fluid.

In the vertical support mechanism 9 as shown in FIG. 7, if the restoring force due to the curved rail-shaped members 92 and 95 alone is not sufficient, a restoring mechanism can be separately added. As a device capable of applying a horizontal restoring force even if the upper structure slightly moves up and down, for example, as shown in FIG. What inserts a coil spring 111 etc. can be used.

Each of the embodiments shown in FIGS. 1, 6 and 7 described above has a vertical support mechanism for supporting the upper structure via a rolling element, and also uses a device for applying a restoring force or damping. However, the restoring mechanism and the damping mechanism are not limited to those used in the above-described embodiment, and various modes can be used. Some examples will be described below.

FIGS. 10 and 11 show an example of an apparatus which can apply both restoring force and damping.

In the apparatus 13 shown in FIG. 10, a right angle of a right-angled triangular frame 131 is rotatably supported by a support shaft 132, and a horizontal rod 133 is rotatable at an upper apex angle. The horizontal movement of the upper structure 2 is transmitted by being combined. The upper end of a vertically arranged coil spring 134 is joined to the lateral apex angle, and the lower end of the coil spring 134 is fixed to the foundation 1.
The coil spring 134 is disposed in a container 135 containing a viscous fluid, and viscous resistance acts on the displacement of the coil spring 134.

In such a device 13, the horizontal movement of the upper structure 2 is converted into a vertical displacement by the rotation of the right-angled triangle frame 131, and a restoring force is applied by the coil spring 134. Damping is provided by the viscous fluid.

The device 14 shown in FIG. 11 is substantially the same as the restoring / damping mechanism 7 shown in FIG. 3, except that a plurality of steel rods 72 are used instead of the lower plate 141 and the upper plate 143.
And a plurality of plate-like members 142 are vertically arranged.
In such an apparatus, the viscous fluid 144 is filled between the plate-like members 142, so that the contact area is large and the damping effect is large. However, since the directionality is generated by using the plate-like member 142, two devices arranged so as to be perpendicular to each other are used in order to impart damping to the vibration in all directions in the horizontal plane. There is a need.

The apparatus shown in FIGS. 12 to 15 is an example of an apparatus for applying a horizontal restoring force.

The apparatus 15 shown in FIG. 12 has a rubber member 151 having a box-shaped cross section interposed between the vertical plane of the upper structure 2 and the vertical plane of the foundation 1. This rubber material 151
Is substantially the same as that used as a fender in a sun bridge or the like, and has a reinforcing member 151a such as a metal net embedded therein.

The device 16 shown in FIG. 13 is almost the same as the device 13 shown in FIG. 10, except that the coil spring 161 is not disposed in the viscous fluid, and only the restoring force is applied. Has become.

A device 17 shown in FIG. 14 is a device in which a plurality of dish-shaped springs 171 are stacked and interposed in a gap where the vertical surface of the upper structure 2 and the vertical surface of the foundation 1 face each other. The dish-shaped spring 171 is deformed flat by the movement of the body 2,
The repulsive force at this time applies a restoring force to the upper structure 2.

The device 18 shown in FIG. 15 is substantially the same as the device 4 shown in FIG. 9 except that a lead material is not used in this device, and the device 18 is mainly used for providing a restoring force. Can be

The apparatus 19 shown in FIG. 16 comprises a lower member 192 having a plurality of plate members 192b erected from a base 192a fixed to a foundation via a lower plate 191; The main part is composed of an upper member 193 provided so that a plurality of plate-like members 193b protrude downward from a base 193a fixed to the base member 193, and the plate-like members of the lower member 192 and the upper member 193 alternately mesh with each other. It is installed in.

In this device 19, the superstructure 2 and the foundation 1
Are displaced in the horizontal direction, the plate members 192b, 193b
Is bent, and a restoring force is applied to the upper structure 2 by the force of the plate-like member returning to the original shape.

The device 20 shown in FIG. 17 is a device for applying attenuation, and has almost the same configuration as the device 10 shown in FIG. However, in this device, the bottom surface of the container 201 storing the viscous fluid is flat, and the lower surface of the circular plate 202 supported by the upper structure 2 and facing the bottom surface is also formed flat.

Such an apparatus is used for a structure in which the upper structure 2 does not displace in the vertical direction, and is damped by the viscous fluid between the bottom surface of the container 201 and the lower surface of the circular plate 202.

[0058]

As described above, in the seismic isolation structure according to the first and second aspects of the present invention, even when a ground motion in an arbitrary direction in a horizontal plane is input to the foundation, the ground motion transmitted to the upper structure is obtained. Can be greatly reduced, and the rolling of the upper structure during an earthquake can be minimized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a seismic isolation structure according to an embodiment of the first invention.

FIG. 2 is a schematic cross-sectional view of the vertical support mechanism shown in FIG.

FIG. 3 is a schematic sectional view of the restoration / damping mechanism shown in FIG. 1;

4 shows seismic waves in the X direction recorded on the foundation and superstructure of the embodiment shown in FIG. 1. FIG.

5 shows seismic waves in the Y direction recorded on the foundation and the superstructure of the embodiment shown in FIG. 1. FIG.

FIG. 6 is a front view and a side view showing a vertical support mechanism of a seismic isolation structure according to a second invention.

FIG. 7 is a front view and a side view showing another example of the vertical support mechanism shown in FIG.

8 is a schematic sectional view showing an example of a damping mechanism that can be used in the embodiment shown in FIG.

FIG. 9 is a schematic configuration diagram illustrating an example of a restoration mechanism.

FIG. 10 is a schematic configuration diagram illustrating an example of a restoration / attenuation mechanism.

FIG. 11 is a schematic configuration diagram illustrating an example of a restoration / attenuation mechanism.

FIG. 12 is a schematic configuration diagram illustrating an example of a restoration mechanism.

FIG. 13 is a schematic configuration diagram illustrating an example of a restoration mechanism.

FIG. 14 is a schematic configuration diagram illustrating an example of a restoration mechanism.

FIG. 15 is a schematic configuration diagram illustrating an example of a restoration mechanism.

FIG. 16 is a schematic configuration diagram illustrating an example of a restoration mechanism.

FIG. 17 is a schematic configuration diagram illustrating an example of a damping mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Foundation 2 Upper structure 6,8,9, Vertical support mechanism 61,81,91 Lower plate 66,85,96 Upper plate 62,92 First rail member 65,95 Second rail member 63,93 Lower frame 64,94 Upper frame 67,97 Steel ball (spherical body) 98 Ball seat 82 First support plate 83 Second support plate 84 Third support plate 82a First rail-shaped convex portion 84a Second rail Convex portions 83a, 83b groove portions 86 cylindrical body

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16F 15/023 F16F 15/023 A

Claims (6)

[Claims] 1. A seismic isolation structure comprising a plurality of vertical support mechanisms for supporting a vertical load of an upper structure between a foundation and an upper structure built thereon, wherein the plurality of vertical supports are provided. Each of the mechanisms includes a first single rail-shaped member fixed to an upper surface of the foundation via a lower plate, and a lower surface of the upper structure so as to intersect the first single rail-shaped member at right angles. A second single rail member fixed via an upper plate, and a longitudinal movement of both rail members at an intersection of the first single rail member and the second single rail member. A movable body provided so as to be capable of being provided, wherein the movable body is engaged with the first single rail-shaped member, and a lower movable body is engaged with the second single rail-shaped member. A grooved rolling surface formed on a top surface and side surfaces of the first single rail-shaped member. A number of rolling elements are interposed between the lower movable body and between the grooved rolling surfaces formed on the upper surface and side surfaces of the second single rail-shaped member and the upper movable body, and A seismic isolation structure wherein an upper surface of the lower movable body and a lower surface of the upper movable body are overlapped with each other. 2. An apparatus according to claim 1, wherein an upper surface of said first single rail member is formed linearly, and a lower surface of said second single rail member is formed linearly. Seismic isolation structure. 3. The seismic isolation structure according to claim 1, wherein a restoring and / or damping mechanism is provided between the foundation and the upper structure. 4. A seismic isolation structure provided with a vertical support mechanism for supporting a vertical load of an upper structure built on a foundation, wherein the vertical support mechanism includes a first support plate as a lowermost layer and a first support plate. It comprises a second support plate as an intermediate layer and a third support plate as an uppermost layer, the lower surface of the first support plate is fixed to a foundation, and the upper surface of the third support plate is fixed to an upper structure. Along with
A plurality of first rail protrusions having an inverted V-shaped cross section extending in a first direction are formed on an upper surface of the first support plate, and the first support protrusions are formed on a lower surface of the second support plate. A plurality of first rail recesses having a V-shaped cross section extending in the direction and engaging with the first rail protrusions are formed, and the upper surface of the second support plate is perpendicular to the first direction. A plurality of second rail protrusions having an inverted V-shaped cross section extending in the second direction are formed, and the lower surface of the third support plate extends in the second direction and extends along the second direction. A seismic isolation structure, wherein a plurality of second rail recesses having a V-shaped cross section that engage with the second rail protrusion are formed. 5. A plurality of cylindrical rolling elements which are rotatably engaged between the first rail projection and the first rail recess, and are provided between the first rail projection and the first rail recess. The seismic isolation structure according to claim 4, wherein a number of cylindrical rolling elements are provided between the convex portion and the second rail concave portion so as to rollably engage with each other. 6. The seismic isolation structure according to claim 4, wherein a restoring and / or damping mechanism is provided between the foundation and the upper structure.