JP3074800U - Seismic isolation bearing board - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To support a structure with a large number of steel ball free wheels interposed on a spherical seat of a base, and to receive only a seismic force such as a horizontal force phase slightly exceeding the rolling friction force of the free wheels. Causes the rolling displacement of the free wheel, avoids the seismic motion and avoids it.At the end of the seismic motion, the displacement is gradually reduced and restored to the central low position of the spherical seat, and the upward displacement of the structure is restrained, and the structural strength It is intended to provide a safe and seismic base plate. SOLUTION: A plate-shaped annular spherical seat 2 which is opened at the center upper part of a base 1 is formed, and a pair of disk-shaped flange plates 3 are provided at upper and lower end positions of a support cylinder 4 inside the central opening of the spherical seat. 3 are arranged side by side on the spherical seat so as to face each other, and around the upper flange plate, a large number of steel ball free wheels 5 and 5 are annularly arranged and mounted on the spherical seat upper surface. In the vicinity of the periphery, an annular peripheral edge 6 protrudes directly below the lower surface of the spherical seat, and an articulated joint 8 is provided in the upper part of the support cylinder, and a bearing plate 7 is supported on the upper part of the joint to support a structure. Has been established.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The purpose of the present invention is to prevent the structural damage or collapse caused by external force exceeding the seismic force defined as the value obtained by multiplying the structural load by the horizontal seismic intensity or the seismic layer shear force coefficient. The present invention relates to seismic isolation means for reducing external force.

[0002]

[Prior art]

 Conventionally, a structure is supported on the friction support surface on the foundation against earthquake motion, and a slip displacement is easily generated with a response seismic force that slightly exceeds the friction force of the friction surface, so that the seismic motion can be avoided in a flowing manner. A seismic isolation device called a slip system or an insulation system uses a low friction coefficient material such as Teflon, stainless steel plate, bronze plate, anti-friction material, and ball bearing to reduce the frictional force of the friction surface that supports the structure. Since the bearing means were used, the sliding displacement due to the seismic motion was relatively large, and it remained residual even after the seismic motion ended, and did not have the function of restoring the original position.

[0003] Then, an articulated slider C projecting below the structural support plate B is supported on the dish-shaped spherical surface of the support plate B shown in FIG. It slides from the center, displaces in a pendulum shape, avoids the seismic ground motion, avoids the seismic ground motion, and restores the seismic ground motion to the lower center of the support plate as well as the seismic ground motion. On the conical surface, a large-diameter steel ball free wheel is supported by rolling a large-diameter steel ball through a large number of small-diameter steel balls E to the inside of the bearings that support the structure. However, it has been proposed that the rolling wheel is displaced from the center of the support board to avoid the seismic motion in a flowing manner, and that the seismic motion is attenuated, and that the bearing that supports the universal wheel and the structure rolls back to the center of the support board and is restored.

[0004]

[Problems to be solved by the invention]

 Among those described in the prior art, seismic isolation devices called so-called slip type or insulation type, which support the structure without fixing it to the friction support surface on the foundation, are designed to provide a structure on the friction surface against earthquake motion. Slip displacement can be easily caused by the response seismic force such as horizontal force phase slightly exceeding the friction force of, and the seismic motion can be avoided by avoiding the slip, but the slip displacement at that time becomes a residual displacement even after the seismic motion ends. 4 and 5 cannot be restored to the original position, and the structure shown in FIGS. 4 and 5 only requires that the bearing plate or the support of the structure be placed on the friction surface on the plate-like support plate. In response to seismic motion, the supporting plate or support can be displaced from the center of the support plate to avoid seismic motion by the response seismic force slightly exceeding the frictional force on the friction surface. Against displacement Since there is no bundling means, there is a risk of rocking vibration of the structure due to seismic motion, that is, rocking vibration, and the floating displacement of the structure supporting position due to wind load is not restricted, and any structural support is not possible due to structural strength. There was a problem that it became certain.

[0005] In addition, the structure shown in Fig. 5 supports the structural load with the large-diameter steel ball free wheel alone. The problem is that the mechanical shear stress tends to concentrate on the surface layer at the contact point, which tends to damage the steel ball universal wheel and the surface layer of the support plate.

[0006] The present invention has been made in view of such problems in the prior art, and has as its object the purpose of interposing a structure by interposing a number of steel ball free wheels on a spherical seat of a base. When the bearing receives a seismic force, such as a horizontal force phase, that slightly exceeds the rolling friction force of the free wheel, the free wheel causes rolling displacement, avoids seismic motion and avoids it, and gradually reduces the displacement when the seismic motion ends. In addition to restoring the spherical seat to the central low position, the upward displacement of the structure is restrained, and a seismic isolation bearing board that is safe in terms of structural strength is provided.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the seismic isolation bearing plate of the present invention forms a dish-shaped annular spherical seat which is opened at the center position on the base laid on the foundation, and supports the spherical seat inside the center opening of the spherical seat. A pair of disk-shaped flange plates are arranged at the upper and lower ends of the cylinder so as to face each other on the upper and lower surfaces of the spherical seat, and a number of steel ball free wheels are annularly arranged around the upper flange plate. It is placed on the upper surface, and near the lower flange plate, an annular rim is protruded just below the lower surface of the spherical seat, an articulated joint is provided in the upper part of the support cylinder, and the structure is placed on the upper part of the joint. A support plate is provided for support.

Further, as the joint joint, a socket may be provided in the upper portion of the support cylinder, and a ball joint may be fitted to the socket to form a spherical pair, and a spherical joint may be applied.

Further, the joint joint may be provided with a so-called hook universal joint in which a pair of forks is connected in a cross shape via a cross-shaped pin above the support cylinder.

[0010] At the maximum displacement position of the flange plate, a rubber elastic bush may be fitted around the support cylinder between the support cylinder, which is a structural limit, and the annular inner surface of the spherical seat.

In addition, when the structure is supported on a support plate via a steel ball universal wheel on the spherical seat, and the steel ball universal wheel rolls along the spherical surface of the spherical seat due to a horizontal external force, and is rotationally displaced, The horizontal angle slightly exceeds the average inclination angle of the common tangent plane at the contact point between the spherical seat and the steel ball free wheel, the rolling friction coefficient between the spherical seat and the steel ball free wheel, the rolling friction angle, and the rolling friction force determined by the structural load. Displacement is caused by seismic force such as external force, and the maximum rotational displacement angle of the steel ball free wheel corresponding to the maximum value of this displacement is set.

[0012]

[Embodiment of the invention]

 DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention will be described with reference to the drawings based on an embodiment. Referring to FIGS. 1 to 3, a spherical annular seat 2 of a dish-shaped annular hard thick plate opened at a central position on a base 1 laid on a foundation is shown. In the center opening of the spherical seat, a pair of disk-shaped flange plates 3 and 3 are arranged side by side on the upper and lower ends of the support cylinder 4 so as to face each other on the lower and upper surfaces of the spherical seat. In the vicinity, a large number of steel ball rolling wheels 5, 5 having a low coefficient of friction, so-called ball casters, with a large diameter steel ball rolling around the outer periphery of a large diameter steel ball, are arranged in a ring shape. In order to restrain the upward displacement of the lower flange plate mounted on the upper surface of the seat, an annular peripheral edge 6 is provided near the periphery of the lower plate, and protrudes directly below the lower surface of the spherical seat. One of the pair of articulated joints 8 is provided in a built-in manner, and a support for supporting a structure is provided above the other of the pair. The plate 7 is 支設.

In FIG. 2, the articulated joint 8 may be a spherical pair in which a socket 10 is provided above the support cylinder 4 and a ball joint 9 for supporting the bearing plate 7 is fitted.

In FIG. 4, the articulated joint 8 is a so-called cross-shaped pin 11 in which a pair of forks 12, 12 on the upper side of the support cylinder 4 and the lower side of the support plate 7 are connected in an intersecting manner. The universal joint 13 of the hook may be applied.

When the rolling friction coefficient μ on the spherical seat of the steel ball free wheel and the rolling friction angle as the arc tangent of the friction coefficient are λ, when the free wheel starts to be displaced by a horizontal external force, The average inclination angle of the common tangent plane between the steel ball and the spherical seat on the upward displacement side free wheel and the downward displacement side free wheel is θ and −θ, respectively, the structural load is W, and the average displacement angle is W. Assuming that the load shared with the down displacement free wheel is 0.5 W, the rolling friction forces F _{1 and} F ₂ on the up displacement side and the down displacement side free wheel are given by Formulas 1 and 2, respectively. If the term of a small number of a higher order tangent is omitted, the effect of θ on the tilt angle is almost canceled out, and becomes approximately W tan λ, that is, μW. , Causing rolling displacement.

[0016]

(Equation 1)

[0017]

(Equation 2)

[0018]

(Equation 3)

As an example of the numerical values of Equations 1 to 3, the average inclination angle θ of the ascending surface of the steel ball free wheel on the spherical seat is 5 °, and the average inclination angle −θ of the descending surface is −5 °. Assuming that the rolling friction coefficient μ is 0.01, the rolling tangent angle λ is 0.57 ° as the inverse tangent. For example, when the structural load W is 100 tons, the rolling friction force of all the universal wheels is calculated according to Equation 3. μW is 1 ton irrespective of the average inclination angle between the climbing surface and the descending surface of the steel ball free wheel on the spherical seat, and a horizontal force slightly exceeding this is a horizontal external force required for rolling displacement.

The rolling friction angle λ is defined as the arc tangent of the structural load W, the rolling tangent of the rolling friction coefficient μ between the spherical seat and the steel ball free wheel, and the steel on each of the upward and downward displacement free wheels on the spherical seat. The average inclination angles of the common tangent plane of the sphere and the spherical seat are θ and −θ, respectively, the structural load is W, and the shared load of each free wheel on the ascending and descending displacement sides is 0.5 W, respectively. the horizontal external force, freely when wheel rotates displaced have you to the rotational displacement angle α from the horizontal position along the spherical seat, the horizontal external force climbs displacement side of the freely moving wheel H ₁ is the number 4, the downlink displacement side horizontal force H ₂ Is given by Equation 5, and the sum H of the horizontal external forces on both sides is given by Equation 6, and the allowable seismic force such as the horizontal external force slightly higher than this is set.

[0021]

(Equation 4)

[0022]

(Equation 5)

[0023]

(Equation 6)

As numerical examples of Equations 4 to 6, the structure load W is 100 tons, the average inclination angle θ of the common tangent plane between the initial spherical seat and the steel ball free wheel is 5 °, and the rotational displacement angle α Is 5 °, the rolling friction coefficient μ is 0.01, and therefore the rolling friction angle λ is 0.57 °, the horizontal force H applied to all the universal wheels of Equation 6 is 9.8 tons, which is equivalent to When a horizontal seismic intensity is applied, the horizontal seismic intensity is calculated, which corresponds to a seismic intensity of 0.098 G, that is, 96 gal (corresponding to seismic intensity class V), and a rotational displacement occurs up to a rotational displacement angle of 5 °.

In order to set the rotational displacement angle α to 5 ° and to set the displacement on the spherical surface to 20 cm in chord length, the radius of curvature of the spherical seat is set to 229 cm.

Further, the rotational displacement angle α is set to an angle that does not hinder practical use, and when a horizontal force exceeding the set response seismic force is received, the contact position between the annular inner position of the spherical seat and the support cylinder is changed. As a structural limit, a rubber elastic bush 14 having a high vibration damping property is fitted around the support cylinder in order to buffer and receive the horizontal force.

Further, the rolling friction angle as the arc tangent of the rolling friction coefficient μ between the spherical seat and the steel ball universal wheel is λ, and the universal wheel is rotationally displaced along the spherical seat by a horizontal external force, and When the horizontal external force disappears due to the rotation displacement angle reaching β, the structural load is W, and the shared load between the rising position and the descending position of the free wheel is 0.5 W, respectively. resulting tendency to be displaced to the downstream side by the horizontal force Q ₁ is the number 7, results in a tendency to be displaced to the climb side by the horizontal force Q ₂ is the number 8 of the descending position side, the horizontal force Q according to the total free wheel, the number 9 the sum of both the horizontal forces, negative numbers indicate a restoring force of the horizontal force Q ₁ direction, i.e. to the spherical seat center low.

[0028]

(Equation 7)

[0029]

(Equation 8)

[0030]

(Equation 9)

As a numerical example of Equations 7 to 9, when the seismic motion ends at a rotational displacement angle β of 5 °, the structural load W is set to 100 tons, and the common contact between the spherical seat and the steel ball free wheel is performed. When the average inclination angle on the upward displacement side of the plane is 5 °, the average inclination angle on the downward displacement side −θ is −5 °, and the rolling friction coefficient μ is 0.01, therefore, when the rolling friction angle λ is 0.57 °, The horizontal force Q applied to all 9 free wheels is -7.8 tons, and this negative number indicates the restoring force to the lower spherical seat.

[0032]

[Effect of the invention]

 Since the present invention is configured as described above, the following effects can be obtained.

In the seismic isolation bearing board of the first aspect, a bearing plate for supporting the structure via a large number of steel ball free wheels annularly arranged on a spherical seat on the base is mounted, and the seismic motion or wind pressure is applied. The horizontal force slightly exceeds the rolling friction force between the spherical seat and the steel ball of the universal wheel, and the bearing plate supporting the structure with the universal wheel rolls eccentrically on the spherical seat. By doing so, it is possible to reduce the response seismic force to the same level of horizontal external force, etc., and avoid the seismic ground motion.

The peripheral edge 6 near the lower flange plate abuts against the lower surface of the spherical seat and restrains the upward displacement of the bearing plate when a vertical vibration due to seismic motion or a levitation force due to wind load is applied. The rocking vibration and the floating displacement of the structure supported by the above can be suppressed.

When the horizontal external force disappears when the horizontal external force causes a rotational displacement of the steel ball free wheel along the spherical seat, the structural load and the rolling friction angle between the steel ball free wheel and the spherical seat and the rotation A horizontal force in the direction of gradually decreasing the displacement in accordance with the displacement angle, that is, a restoring force is generated, so that the structure and the bearing plate can be restored to the central lower position on the spherical seat.

In addition, since the structure load is shared at the contact point between the spherical seat and the steel balls of a large number of free wheels supported on the seat surface, the static shear stress of Hertz at the contact point is reduced, and the steel ball is reduced. The free wheel and the thin layer near the surface of the spherical seat are not damaged.

Furthermore, when the seismic force exceeds the set value of the horizontal external force required for the above-mentioned rolling displacement, the structure is displaced to the structural limit between the annular inner surface of the spherical seat and the support cylinder, and the vibration damping fitted to the outer periphery of the support cylinder is performed. It can be cushioned by a rubber elastic bush that is rich in properties.

Further, in order to use a large number of small steel ball free wheels and make the shape relatively flatter than that using a large large diameter steel ball free wheel, the structure is supported on a foundation. The height of the so-called bearing layer is reduced to facilitate the construction of the structure, and a structure with good structural strength and stability can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a base isolation bearing board.

FIG. 2 is a cross-sectional view of a main part along AA in FIG. 1;

FIG. 3 is a sectional view of a main part showing details of a part B in FIG. 2;

FIG. 4 is a sectional view of a main part of an embodiment in which a universal joint is applied to an articulated joint.

FIG. 5 is a cross-sectional view of a main part of a conventional support having a dish-shaped spherical surface as a support plate.

FIG. 6 is a sectional view of a main part of a conventional rolling bearing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Base board 2 Spherical seat 3 Flange plate 4 Support cylinder 5 Steel ball universal ring 6 Peripheral edge 7 Bearing plate 8 Joint joint 9 Ball joint 10 Socket 11 Cross pin 12 Fork 13 Universal joint 14 Rubber elastic bush A Support board B Structural support Plate C Slider D Supporting tool E Small-diameter steel ball F Large-diameter steel ball G Large-diameter steel ball swivel wheel As a symbol not shown in the following equations 1 to 9, W Structure load μ Rolling friction coefficient λ Rolling friction angle θ Spherical seat Average tilt angle of the common tangent plane between the ball and the steel ball free wheel α Rotational displacement angle (of the rotational displacement of the steel ball free wheel on the spherical seat) β Rotational displacement angle (the rotational displacement angle when the horizontal external force disappears) F ₁ climb to α rotational displacement angle of the rolling friction force H ₁ steel ball freely moving wheel of the rolling friction force F total steel ball freely moving wheel of the downlink displacement side of the rolling friction force F ₂ steel ball freely moving wheel climb displacement side of the steel ball freely moving wheel Outside horizontal required for displacement Steel ball freely moving wheel raised position in the horizontal external force Q ₁ rotation displacement angle β required to displacement of the H ₂ rotational displacement angle of the horizontal external force H total steel ball freely moving wheel required for downlink displacement of the rotational displacement angle α of the steel ball freely moving wheel α Horizontal force on the downward side Q Horizontal force on the upward side from the descending position of the steel ball universal rotation at _two rotational displacement angles β Q Horizontal force of all the steel ball universal wheels at the rotational displacement angle β

Claims (1)

[Utility model registration claims] An annular plate-shaped spherical seat (2) opened at a central position on a base (1) laid on a foundation is formed, and the upper and lower sides of a support cylinder (4) are formed inside the central opening of the spherical seat. At the end position, a pair of disk-shaped flange plates (3, 3) are arranged side by side on the spherical seat so as to face each other. And mounted on the upper surface of the spherical seat, an annular rim (6) is protruded immediately below the lower surface of the spherical seat near the lower flange plate, and an articulated joint (8) is provided in the upper portion of the support cylinder. A seismic isolation bearing board with a bearing plate (7) installed above the joint to support the structure.