JP2002322827A - Base isolation building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation building having a small scale as mechanism, advantageous in cost with good workability, and capable of minimizing the torsion in the application of a horizontal load. SOLUTION: This base isolation building 1 comprises a base isolation device between a foundation 2 and an upper building 3. An auxiliary restoration device 10 is set near the circumference of the upper building 3, and the torsion caused in the application of the horizontal load is minimized by the slippage of the planer center of gravity G of a base isolation layer including the upper building 3 and the planer rigidity center K of the base isolation layer. The auxiliary restoration device 10 is set in the position where the extension line L of the line connecting the center of gravity G to the rigidity center K crosses the peripheral edge of the upper building 3. An auxiliary mass 11 may be set instead of the auxiliary restoration device 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base-isolated building using a base-isolation restoring device, and more particularly, to the rotation and torsional vibration of a base-isolated section such as an upper building against a non-base-isolated section such as a foundation. Regarding seismically isolated buildings that can be prevented.

[0002]

2. Description of the Related Art Conventionally, as a seismic isolation structure of this kind, there is a technique described in Japanese Patent Application Laid-Open No. Hei 6-66347. In this technology, a pair of pulleys rotatable around a vertical axis are attached to the front and rear position of the middle part in the left and right direction on the lower surface of the seismic isolation floor, and move in the front and rear direction to the left and right front and right front and rear positions of the building floor. A flexible support portion is provided, and a wire wound around one pulley on the front side and one pulley on the rear side is stretched between the support portion at the left front position and the support portion at the right rear position. A wire wound around the other pulley on the front side and the other pulley on the rear side is stretched between the support portion at the front position and the support portion at the rear left position.

[0003] In this method, it is possible to reliably suppress only the rotational motion without suppressing the translational movement of the seismic isolation part relative to the non-seismic part. Even if the wire is displaced in the left-right direction relative to the part, only the part of both wires that is wound around each pulley and bent is displaced, and the lengths of both wires themselves do not change. The relative displacement in the left-right direction with respect to the part is not restricted at all. Also, in seismic isolation buildings that are restored or elastically insulated by horizontal vibration, seismic isolation devices are usually installed so that the center of gravity of the upper building and the rigidity of the seismic isolation layer match as much as possible. The primary natural period and eccentricity of
Design the rigidity of the restoration device to meet the target value.

[0004]

By the way, the above-mentioned seismic isolation structure is caused by a difference between the rigidity of the seismic isolation layer and the center of gravity of the upper building.
The torsion that occurs during seismic isolation is forcibly brought to the translational motion, which affects the translational motion of the portion where the torsional energy is suppressed. In addition, there is also a problem that the mechanism is large and difficult to realize in terms of workability and feasibility. In addition, the seismic isolation device is installed so that the center of gravity of the upper building and the rigidity of the seismic isolation layer match, and the rigidity of the restoration device is set so that the primary natural period and eccentricity of the seismic isolation layer match the target values for each house. When designing a standardized house, such as an industrialized house,
The operation becomes inefficient and complicated, and may be very expensive.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a seismically isolated building which is mechanically small-scale, has good workability, and is advantageous in cost. To provide. In addition, seismic isolation buildings can be added later as an auxiliary component, thereby reducing torsion when a horizontal load is applied and having sufficient torsional strength when a horizontal load such as an earthquake is applied. Is to provide.

[0006]

In order to achieve the above object,
A base-isolated building according to the first aspect of the present invention is a base-isolated building provided with a base-isolation device between a foundation and an upper building, and an auxiliary restoration is provided between the foundation near the outer periphery of the upper building and the upper building. The device is installed to reduce the torsion that occurs when a horizontal load is applied due to the difference between the planar center of gravity of the seismic isolation layer including the upper building and the planar rigid center of the seismic isolation layer. . According to this configuration, the rigidity can be made closer to the center of gravity by installing the auxiliary restoring device, and the amount of eccentricity between the rigidity and the center of gravity can be reduced, so that the torsion when a horizontal load acts is reduced. Can be. Further, in an industrialized house, the efficiency of manufacturing, design and construction can be improved. In the base-isolated building according to the invention of claim 2, in the base-isolated building, the auxiliary restoring device intersects an extension of a line connecting the center of gravity and the rigid center with an outer periphery of the upper building. It is characterized by being installed at a position. According to this configuration, when a horizontal load is applied due to an earthquake or the like, the torsion of the seismic isolation layer can be reduced.

According to a third aspect of the present invention, there is provided a seismic isolation building having a seismic isolation device between a foundation and an upper building, wherein an auxiliary mass is provided at a lower portion near an outer periphery of the upper building. Is installed, and the torsion that occurs when a horizontal load is applied due to a shift between the planar center of gravity of the seismic isolation layer including the upper building and the rigid center of the seismic isolation layer is reduced. According to this configuration, by installing the auxiliary mass at the lower part of the outer periphery of the upper building, the rigid center can be made closer to the center of gravity, and the amount of eccentricity between the rigid center and the center of gravity can be reduced, so that when a horizontal load is applied. The torsion of the base isolation layer can be reduced. Further, in an industrialized house, the efficiency of manufacturing, design and construction can be improved.

Further, in the base-isolated building according to the invention of claim 4, in the base-isolated building, the auxiliary mass is an extension of a line connecting the center of gravity and the rigid center and an outer periphery of the upper building. It is characterized by being installed at the position where it intersects with. According to this configuration, when a horizontal load is applied due to an earthquake or the like, the torsion of the seismic isolation layer can be reduced.

A seismic isolation building according to the invention of claim 5 is
A seismic isolation building provided with a seismic isolation device between a foundation and an upper building, wherein a low-elasticity auxiliary restoring device is installed for the sum of the horizontal rigidity of the seismic isolation device, and the seismic isolation layer including the upper building is provided. The torsion which occurs when a horizontal load is applied due to the deviation between the planar center of gravity of the above and the rigid center of the seismic isolation layer is reduced. According to this configuration, the rigidity can be made closer to the center of gravity by installing a low-elasticity auxiliary restoring device with respect to the sum of the horizontal rigidity with respect to the restoration of the seismic isolation device, and the eccentricity between the rigidity and the center of gravity can be reduced. Therefore, the torsion when a horizontal load is applied can be reduced. Therefore, it is possible to optimally design a seismic isolated building having a necessary torsional strength against horizontal loads such as seismic force, and to achieve a seismic isolated building having a simple configuration and capable of reducing costs.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a seismic isolation building according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a floor plan of a base-isolated building according to the present embodiment, and FIG.
FIG. 3 is a front view as viewed from the line A, FIG. 3 is a side view as viewed from the line BB in FIG. 1, and FIG. 4 is a schematic plan view of a building unit installed on the reinforcing frame in FIG. In FIGS. 1-4, seismic isolation building 1
Is provided with a seismic isolation bearing device 4 and a restoring damping device (hereinafter referred to as a restoring device) 5 between the foundation 2 and the upper building 3, so that the displacement of the foundation 2 is not directly transmitted to the upper building 3. . The seismic isolation device is constituted by the seismic isolation bearing device 4 and the restoration device 5. The upper building 3 is formed by connecting _five building units U _{1 to} U ₅ having a box ramen structure in this example, and a reinforcement frame 6 is located at the lowest level.

The seismic isolation bearing device 4 is for supporting the vertical load of the upper building 3. In this example, a cross linear bearing device in which the linear motion device is fixed to be orthogonal to the upper building 3 is used.
8 between the foundation 2 and the reinforcement base 6 corresponding to the corner of
Used. The restoration device 5 is made of an elastic material such as natural rubber, chloroprene rubber, silicone rubber, or acrylic resin, and absorbs and attenuates seismic energy during an earthquake and restores displacement. Restoration device 5
The lower supporting portion 5a is fixed to the foundation 2, the upper supporting portion 5b is fixed to the reinforcing frame 6 of the upper building 3, and the intermediate elastic body 5c connects the upper and lower supporting portions. In this example, seven restoration devices 5 are used corresponding to the intermediate portions of the beams of the reinforcing base 6.

The seismic isolation bearing device 4 and the restoring device 5 constitute a seismic isolation layer, permitting relative movement between the foundation 2 and the upper building 3 to absorb and attenuate seismic energy. In addition,
In this example, a cross linear bearing device is used as the seismic isolation bearing device 4, and a restoring device connected by an elastic body is used as the restoring device 5. However, as the seismic isolation bearing device 4, a sliding bearing device or rubber is used. A laminated rubber device or the like in which steel sheets and steel plates are laminated in multiple layers may be used, and a damping device using a lead plug or the like may be used as the restoration device 5.

The plane center of gravity of the upper building 3 in the seismic isolation layer is indicated by a center of gravity G. The center of gravity G can be obtained from the X and Y coordinates of the center of gravity of each of the building units U _{1 to} U ₅ and the weight thereof. That is, five X coordinate X ₁ to X of the center of gravity of the building unit _5, Y coordinate Y ₁ to Y _5, weight W
If it is ₁ to _W-5, X of the center of gravity G, Y coordinates Gx, Gy, respectively the number of the next 1, determined by the number 2.

[0014]

(Equation 1)

[0015]

(Equation 2)The rigidity of the upper building 3 in the seismic isolation layer is represented by the rigidity K.
Is shown. The rigidity K has a horizontal force acting on the floor of the upper building 3.
For example, when the floor of the seismic isolation layer rotates in the horizontal plane
The center. The rigidity K is, as shown in FIG.
U₁~ U_FiveX and Y coordinates of the horizontal side of₆~ X₇, Y
₆~ Y₈And a bar corresponding to the upper horizontal side of each building unit.
C₁₁~ C₁₄, C_{twenty one}~ C_{twenty four}, C₃₁~ C₃₄, C₄₁~
C₄₄, C ₅₁~ C₅₄Then, the X and Y coordinates Kx of the rigidity K,
Ky is obtained by the following equations (3) and (4).

[0016]

(Equation 3)

[0017]

(Equation 4) Incidentally, the spring constant of each building unit U ₁ ~U ₅ described above is,
For example, when the lower side of one building unit is fixed and a horizontal force is applied to the upper side, the upper side is deformed in the horizontal direction, and the inclination between the applied horizontal force and the horizontal deformation indicates rigidity. Is a constant.

If the center of gravity G and the center of rigidity K do not match,
When a horizontal load is applied, the seismic isolation layer is twisted.
Assuming that the distance between the center of gravity G and the rigid center K is an eccentric distance, the magnitude of the eccentric distance is one index of the torsional strength of the building against a horizontal load such as an earthquake or wind force. That is, the horizontal load acts on the center of gravity G of the building, and if the center of gravity G and the rigidity K do not match, the building is deformed in the horizontal direction and a rotational force around the rigidity K acts. In a building having a large eccentric distance, members that are partially deformed excessively at corners of the building may be generated, and these members may be damaged.

The present invention is to reduce the twist generated as described above. The auxiliary restoration device 10 is installed at a position where an extension line L of a line connecting the center of gravity G and the rigid center K intersects with the outer periphery of the upper building 3. The auxiliary restoring device 10 reduces the torsion of the seismic isolation layer when a horizontal load is applied as described above, and a low elasticity device whose damping constant is set smaller than that of the restoring device 5 is employed. ing. That is, the auxiliary restoration device 10 is a restoration device having low elasticity with respect to the sum of the horizontal rigidities. Then, the auxiliary restoration device 10
Is installed between the footing 2a and the reinforcing frame 6.

The operation of the seismic isolation building of this embodiment configured as described above will be described below. In seismic isolation buildings where restoration or horizontal vibration is insulated by this kind of elastic body,
The seismic isolation device is installed so that the center of gravity G of the upper building 3 and the rigidity K of the seismic isolation layer match as much as possible. In order to realize seismic isolation in a standardized house such as an industrialized house,
If the rigidity of the restoration device 5 is designed so that the primary natural period and the eccentricity of the seismic isolation layer match the target values for each house, it becomes inefficient and complicated work, and becomes very expensive. .

In the case of the base-isolated building 1 of this embodiment, the primary natural period and the eccentricity of the center of gravity G and the center of rigidity K do not match the target values. A torsional force 7 occurs. This torsional force 7 is the torsional resistance 8 in the opposite direction by the auxiliary restoration device 10 located near the outer periphery of the upper building 3.
Counteracted by That is, the torsional resistance 8 acts to cancel the torsional force 7 with respect to the rigid center K which is the center of rotation. As described above, with a simple configuration in which the auxiliary restoration device 10 is simply attached, the twist can be reduced. For this reason, the seismic isolation building 1 can reduce the rotational force around the rigidity K,
Excessive deformation of the outer peripheral member can be prevented, and optimal seismic isolation performance can be achieved.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 5A is a floor plan of another embodiment of the base-isolated building according to the present invention, and FIG. 5B is a sectional view of an auxiliary mass portion. This embodiment is different from the above-described embodiment.
An auxiliary mass is used in place of the auxiliary restoration device. The other substantially equivalent components are denoted by the same reference numerals, and detailed description is omitted. In FIG. 5, an auxiliary mass 11 is installed at a position M where an extension line L of a line connecting the center of gravity G and the rigid center K intersects with a reinforcement base 6 which is a lower portion near the outer periphery of the upper building 3. This auxiliary mass 11
Is, for example, the mass of the upper building 3 is m, the center of gravity G and the rigidity K are
When the distance between the rigid core K and the position M is L2 and the distance between the rigid core K and the position M is L2, the reinforcing base is made of a metal mass such as iron having a mass of about ((L1 / L2) × m}. No. 6 is fixed by bolting or the like with the H-section steel sandwiched from both sides.

In this embodiment, when a horizontal load is applied due to an earthquake or the like as in the above-described embodiment, a torsional force 7 due to the eccentricity of the center of gravity G and the rigid center K is generated. Are counteracted by the torsional resistance 9 in the same direction generated by the auxiliary mass 11 located near the outer periphery of. That is, the torsional resistance 9 acts to cancel the torsional force 7 with respect to the rigid center K which is the center of rotation. As described above, with a simple configuration in which only the auxiliary mass 11 is attached, the torsion can be reduced, and the same effect as in the above-described embodiment can be obtained.

In the above-described embodiment, the auxiliary restoring device 10 or the auxiliary mass 11 is installed at one position where the extension line L connecting the center of gravity G and the rigid center K intersects with the outer periphery of the upper building 3. However, it may be installed at both positions where the extension line L intersects the outer periphery. In this case, the auxiliary restoration device 10 has a damping constant of about half,
Auxiliary mass 11 having a mass of 1/2 can be used.

The auxiliary restoring device 10 may be installed on one side and the auxiliary mass 11 may be installed on the other side. As a seismic isolation restoration device,
Although the example using the seismic isolation bearing device using the cross linear bearing and the restoration damping device is shown, only the restoration damping device may be used. Although an example in which a lump-shaped member is added as the auxiliary mass has been described, any shape such as a rectangular parallelepiped shape or a cylindrical shape may be used as long as a load can be obtained when torsion occurs and a torsional resistance can be obtained.

[0026]

As can be understood from the above description, the seismic isolation building of the present invention can be twisted in the seismic isolation layer simply by installing a low-elasticity and simple auxiliary restoration device at the outer peripheral position of the upper building. Can be reduced. Therefore, the workability is good and economical. In addition, since the effect of horizontal rigidity on the seismic isolation cycle is minimized, seismic isolation performance as designed can be achieved in industrialized houses with various plans. Furthermore, the same effect as in the case of the above-described auxiliary restoration device can be obtained with a simple configuration in which the auxiliary mass is simply installed at the outer peripheral position of the upper building.

[Brief description of the drawings]

FIG. 1 is a floor plan of an embodiment of a base-isolated building according to the present invention.

FIG. 2 is a front view as viewed from the line AA in FIG. 1;

FIG. 3 is a side view as viewed from the line BB in FIG. 1;

FIG. 4 is a schematic plan view of a building unit installed on the reinforcing frame of FIG. 1;

5A is a floor plan of another embodiment of the base-isolated building according to the present invention, and FIG. 5B is a sectional view of an auxiliary mass portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Seismic isolation building 2 Foundation 3 Upper building 4 Seismic isolation bearing device (Seismic isolation device) 5 Restoration damping device (Seismic isolation device) 6 Reinforcement base 7 Torsional force 8, 9 Torsional resistance 10 Auxiliary restoration device 11 Auxiliary mass U _1- U ₅ Building unit G Center of gravity K Rigid center L Extension line M Position of auxiliary mass

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16F 15/02 F16F 15/02 CL 15/04 15/04 EP

Claims (5)

[Claims] 1. A seismic isolation building having a seismic isolation device between a foundation and an upper building, wherein an auxiliary restoration device is installed between the foundation and the upper building near an outer periphery of the upper building, A seismic isolation building characterized by reducing a twist generated when a horizontal load is applied due to a deviation between a planar center of gravity of the seismic isolation layer including the upper building and a planar rigid center of the seismic isolation layer. . 2. The exemption device according to claim 1, wherein the auxiliary restoration device is installed at a position where an extension of a line connecting the center of gravity and the rigid center intersects with an outer periphery of the upper building. Quake building. 3. A seismic isolation building provided with a seismic isolation device between a foundation and an upper building, wherein an auxiliary mass is installed at a lower portion near an outer periphery of the upper building, and a seismic isolation layer including the upper building is provided. A seismic isolation building characterized in that a torsion generated when a horizontal load is applied is reduced by a deviation between a planar center of gravity and a rigid center of the seismic isolation layer. 4. The seismic isolation device according to claim 3, wherein the auxiliary mass is installed at a position where an extension of a line connecting the center of gravity and the rigid center intersects with an outer periphery of the upper building. building. 5. A seismic isolation building having a seismic isolation device between a foundation and an upper building, wherein an auxiliary restoration device having low elasticity is installed for the sum of horizontal rigidity of the seismic isolation device, A seismic isolation building characterized by reducing the torsion that occurs when a horizontal load is applied due to a deviation between the planar center of gravity of the seismic isolation layer including the following and the rigidity of the seismic isolation layer.