JP2615626B2 - Seismic isolation structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a seismic isolation structure for preventing seismic force from being transmitted to devices and structures, and more particularly to a combination of a seismic isolation effect and a damping effect. To an improved seismic isolation structure.

[Conventional technology and prior art] A structure (seismic isolation rubber) in which a plurality of steel plates and rubber plates are alternately laminated is used as a support member that satisfies the anti-vibration properties during an earthquake.
It has been receiving attention recently.

When such seismic isolation rubber is interposed between a rigid building such as concrete and a foundation, it is soft in the lateral direction, that is, the shear rigidity is small. It has the effect of shifting, and the acceleration received by the building due to the earthquake becomes very small.

A major feature of such seismic isolation rubber is that it undergoes elastic deformation that returns to its original position after deformation due to the earthquake, and furthermore, in order to minimize the settlement of the building due to the creep phenomenon of the seismic isolation rubber. In addition, the energy absorption capacity (damping effect) of the seismic isolation rubber itself is extremely small. For this reason, conventionally, the seismic isolation rubber is configured using a rubber material having a small hysteresis loss as a material characteristic.

However, with such a seismic isolation device using only low-damping seismic isolation rubber, the slow rolling of the building during an earthquake remains for a long time even after the earthquake has subsided. There is a danger that not only the seismic isolation rubber itself will be damaged, but also the collision between the building and other structures and the destruction of equipment such as water pipes, gas pipes, and wiring.

Therefore, conventionally, in order to reduce the roll displacement as soon as possible, a method of using a plastic damper made of a soft metal or the like which undergoes plastic deformation immediately when an earthquake force is applied has been adopted. For example, a hollow part is provided inside the seismic isolation rubber, lead is embedded in this part, and the seismic isolation rubber and the damper (damping effect) are imparted by using a plastic deformation during an earthquake to give a damping effect to the seismic isolation rubber. )
It is proposed to have both.

However, in such a seismic isolation device, although the function of absorbing seismic energy is increased, a new coseismic phenomenon caused by the high elasticity of the plastic damper appears in a high-frequency region.

In addition, in the case of seismic isolation rubber containing lead, when the seismic isolation rubber undergoes a large deformation during a large earthquake, the hard plate made of steel damages lead, and the damaged lead damages soft plates such as rubber. Easily breaks. Moreover, the damaged lead is easily broken by repeated large deformation.

The present invention solves the conventional problems described above, and as an improved seismic isolation device having both a seismic isolation effect and a damping effect, a plurality of rigid plates having rigidity and soft plates having viscoelastic properties are alternately provided. Patent application for a seismic isolation device characterized in that a seismic isolation rubber bonded and a plastic damper are provided in parallel, for example, a seismic isolation device incorporating a damper in the seismic isolation rubber (Japanese Patent Application No. 61-
No. 217689. Hereinafter, it is referred to as “first application”. [Problems to be Solved by the Invention] The laminated rubber with a built-in damper disclosed in the above-mentioned prior application shows excellent damping property from small deformation to large deformation, but has a small effect in damping minute vibration. There is.

[Means for Solving the Problems] The present invention provides a seismic isolation structure that exhibits excellent damping properties from small deformation to large deformation and can also exert an excellent effect on minute vibration. Is what you do.

The seismic isolation structure of the present invention provides a cavity in a laminated rubber obtained by alternately laminating a plurality of rigid plates having rigidity and soft plates having viscoelastic properties, and the cavity is formed of a viscoelastic material. A seismic isolation structure in which a damper mainly configured is arranged, and a material having a lower elasticity than the damper is interposed between the damper and the inner wall of the cavity of the laminated rubber. Storage modulus E dynamically measured at 25 ° C, 5Hz, 0.01% strain (However, E _V represents a storage elastic modulus E of the viscoelastic material, E _L is. Showing a storage modulus E of the low modulus material), characterized in that a.

[Action] As described above, the present inventors have solved the conventional problems and have repeatedly studied a seismic isolation device having both a seismic isolation effect and a damping effect. By arranging a specific viscoelastic substance having excellent hysteresis characteristics as a damper, it was possible to obtain a seismic isolation structure with extremely high damping over a wide range from small deformation to large deformation.

However, in this case, even if the above-mentioned specific viscoelastic substance is made to have a large damping property, the elastic modulus becomes higher in small deformation than in the surrounding seismic isolation rubber. Of course, the rate of increase is much smaller than that of a plastic body made of lead or a steel material. However, in order to exhibit high loss properties, it is generally necessary to have a high elastic modulus.

By the way, as a demand of the modern society, there is a countermeasure against micro-vibration for an IC factory, a bio factory, a laser factory, a railway, a house along a road, and the like that require precision processing. In the case of general seismic isolation rubber, the elastic modulus in the lateral direction is low, so that it exhibits an anti-vibration effect even for these minute vibrations and an excellent vibration damping effect.

However, as described above, in the case of a seismic isolation rubber in which a viscoelastic substance is arranged, the elastic modulus of the viscoelastic substance at a minute displacement is high, and as a result, the elastic modulus of the seismic isolation structure is generally not arranged with a viscoelastic substance. Higher than seismic isolation rubber. For this reason, the damping effect for the minute vibration tends to decrease, and the current required characteristics cannot be satisfied.

Therefore, the present inventors conducted further studies to prevent the damper from interfering with the damping action of the seismic isolation rubber against such minute vibrations. between, to the storage modulus E _V viscoelastic material of the main constituent material of the damper, the storage modulus _{E L / E V ≦ 0.9 E} L
It has been found that such an obstructive effect is effectively prevented by arranging a low-elastic material having the following as a cushioning material, and completed the present invention.

Embodiment An embodiment will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing a seismic isolation structure according to one embodiment of the present invention.

As shown in FIG. 1, a seismic isolation structure 1 of the present embodiment is a laminated cylindrical rubber formed by alternately bonding a plurality of rigid plates 11 having rigidity and soft plates 12 having viscoelastic properties. 2 is provided with a cylindrical space in the center thereof, a damper 3 mainly composed of a viscoelastic material is disposed in this space, and a damper 3 is provided between the damper 3 and the inner wall of the cavity of the laminated rubber 2. Also have a low elasticity material (hereinafter, sometimes referred to as a “low elasticity material”) 4 interposed therebetween. In the drawings, reference numerals 13 and 14 are flanges, 20 is a building, and 30 is a foundation.

In the present invention, the shape of the laminated rubber 2, the shape of the cavity thereof, and the shape of the damper 3 may be any shape that can effectively exhibit the seismic isolation effect and the damping effect, and are not restricted at all in terms of shape. Is suitably a columnar body.

Further, the low elastic material 4 does not necessarily need to be provided so as to cover the side surface and the upper and lower surfaces of the damper 3, but may be provided only on the side surface. Further, as shown in FIG. 1, the low elastic material 4 is preferably provided so as to be sealed between the damper 3 and the cavity of the laminated rubber 2.

As shown in FIG. 1, in the seismic isolation structure 1, the size of the laminated rubber 2, the size of the damper 3, the low elastic material 4
There is also no particular limitation on the thickness of the laminated rubber, and it is appropriately selected according to the purpose of use of the seismic isolation structure. For example, the ratio of the diameter l of the cavity of the laminated rubber to the diameter L of the laminated rubber, Is Preferably More preferably It is desirable that

Also, the ratio of the thickness l ₀ of the low elastic material 4 to the diameter l of the cavity of the laminated rubber 2, l ₀ / l, is Preferably It is desirable that

Hereinafter, the respective structural materials of the laminated rubber 2, the damper 3, and the low elastic material 4 of the seismic isolation structure of the present invention will be described.

Examples of the material of the hard plate 11 of the laminated rubber 2 include metals, ceramics, plastics, FRP, polyurethane, wood,
A paper board, a slate board, a decorative board, or the like can be used.
As the soft plate 12, various kinds of materials such as various kinds of organic materials such as vulcanized rubber and plastic, foams thereof, inorganic materials such as asphalt and clay, and mixed materials thereof can be used. The shape of the hard plate 11 and the soft plate 12 may be a circle, a square, or a polygon such as a pentagon or a hexagon.

On the other hand, as a viscoelastic material which is a main constituent material of the damper 3, a hysteresis ratio (h ₅₀ ) at 25 ° C. and 50% tensile deformation is used.
Is preferably 0.2 or more, more preferably 0.3 or more.
Incidentally, at a tensile speed of 200 mm / min, h _50, the stress of the second view - in strain curve Given by the area ratio of

The elastic modulus of the viscoelastic material is 5Hz in frequency and 0.01% in strain.
The value of the storage elastic modulus E dynamically measured at 25 ° C. is 1 ≦ E ≦ 2 × 10 ⁴ (kg / cm ² ), preferably 5 ≦ E ≦ 1 × 10 ⁴ (kg / cm ² ) Is desirable.

The elongation of the viscoelastic material at the time of tensile break is 1
% Or more, more preferably 5% or more,
It is more preferably at least 10%, particularly preferably at least 20%.

Thus, as the low elasticity material 4, 25 ° C., 5 Hz, 0.01
With respect to the storage elastic modulus E dynamically measured at a% strain, E of the low elastic material is E _L , and E of the viscoelastic material is E _V Preferably More preferably Is used.

Such a low elastic material 4 may be any material as long as it satisfies the above characteristics, and various rubbers, plastics, and other materials having the above characteristics among viscoelastic materials exemplified below can be used. . Further, as the low elasticity material, a foamed body, a spring body such as a metal, a plastic, and a rubber, a blanket, a woven fabric, a wallax, and the like can also be used. The low-elastic material layer may be partially a space if necessary.

In the present invention, examples of the viscoelastic material of the damper include an unvulcanized rubber and a vulcanized rubber having the above-mentioned properties, a resin having the above-mentioned properties, a plastic substance, and the like.

In the present invention, the viscoelastic material is preferably an unvulcanized rubber, a vulcanized rubber or the like having the above-mentioned hysteresis ratio and elastic modulus characteristics. For example, ethylene propylene rubber (EPR, EPDM) , Nitrile rubber (N
BR), butyl rubber, halogenated butyl rubber, chloroprene rubber (CR), natural rubber (NR), isoprene rubber (I
R), styrene butadiene rubber (SBR), butadiene rubber (BR), acrylic rubber, ethylene-vinyl acetate rubber (EVA),
Examples include general rubber such as polyurethane, silicone rubber, fluorine rubber, ethylene acrylic rubber, polyester elastomer, special rubber such as epichlorohydrin rubber, chlorinated polyethylene, and thermoplastic elastomer.
When the viscoelastic material is an unvulcanized rubber, the Mooney viscosity ML _{1 + 4 at} 100 ° C. is preferably 10 or more.

These rubber materials may be used alone or as a blend of two or more. In addition, these rubber materials include
Various fillers, tackifiers, lubricants, anti-aging agents, plasticizers,
By mixing a general compounding agent into a rubber material such as a softening agent, a low molecular weight polymer, an oil, etc., the hardness according to the purpose,
Loss characteristics and durability can also be imparted. Particularly, in order to maintain a predetermined performance over a long period of time, a suitable stabilizer such as an antioxidant, a polymerization inhibitor or an anti-scorch agent is added to the above rubber material, or the polymer itself is hydrogenated or otherwise modified. It is extremely effective to achieve stabilization.

In addition, when performing adhesion between the viscoelastic material and other constituent materials, it is generally advantageous to use adhesion using the adhesiveness of the viscoelastic material.
A network by a chemical bond or a physical bond required for the bonding portion may be introduced.

As the viscoelastic material of the present invention, in addition to the unvulcanized rubber and the vulcanized rubber having the above properties, the following substances having the above properties can also be used. For example, necessary for thermoplastics such as polystyrene, polyethylene, polypropylene, ABS, polyvinyl chloride, polymethyl methacrylate, polycarbonate, polyacetal, nylon, polyether chloride, polytetrafluoroethylene, acetylcellulose, ethylcellulose, and these plastics Depending on the type, there may be mentioned those containing the following fillers, plasticizers, softeners, tackifiers, oligomer lubricants and the like.

Fillers: clay, diatomaceous earth, carbon black, silica, talc, barium sulfate, calcium carbonate, magnesium carbonate, metal oxides, mica, graphite, aluminum hydroxide and other flaky inorganic fillers, various metal powders, wood chips, glass Powders, ceramic powders, granular or powdery solid fillers such as granular or powdery polymers, and other various natural or artificial short fibers and long fibers (eg, straw, wool, glass fiber, metal fiber, other various polymer fibers) And other fillers for rubber or resin.

The compounding ratio of the filler is preferably 30 to 250 parts by weight based on 100 parts by weight of the rubber.

As the short fibers, general short fibers such as glass, plastic, and natural products are used. These short fibers also include the following special short fiber reinforcements. For example, the compounding condition of short fibers is to add As in a reinforced rubber composition in which short fibers of a thermoplastic polymer having a phenol formaldehyde type resin are grafted via an initial condensate, those in which short fibers are chemically bonded to rubber are compounded. preferable. The fine short fibers of the thermoplastic polymer have a melting point of 190 to 235 ° C, preferably 190 to 225 ° C, particularly preferably 200 to 220 ° C.
Nylon 6, Nylon 610, Nylon 12, Nylon 611,
Nylon such as nylon 612, polyheptamethylene urea,
It is preferable to form a thermoplastic polymer having a -CONH- group in a polymer molecule such as polyurede or methylene urea or a polyurethane such as polyurethane, particularly nylon, and has an average diameter of 0.05 to 0.8 μm and a circular cross section. It is preferable that the shortest fiber length is 1 μm or more, and the fiber is embedded in the form of fine short fibers in which molecules are arranged in the fiber axis direction.

Softeners: softeners for various rubbers or resins, such as aromatic, naphthenic and paraffinic.

A preferred compounding ratio of the softener is 5 to 150 parts by weight based on 100 parts by weight of the rubber.

Plasticizers: Various ester-based plasticizers such as phthalic acid ester, phthalic acid mixed ester, aliphatic dibasic acid ester, glycol ester, fatty acid ester, phosphate ester, stearic acid ester, epoxy-based plasticizer, and other plastic plastics Or NBR plasticizers such as phthalate, adipate, sebacate, phosphate, polyether and polyester.

A preferable mixing ratio of the plasticizer is 5 to 150 parts by weight based on 100 parts by weight of the rubber.

Tackifiers: various tackifiers (tackifiers) such as coumarone resin, coumarone-indene resin, phenol terpene resin, petroleum hydrocarbons, and rosin derivatives.

A preferable mixing ratio of the tackifier is 1 to 50 parts by weight based on 100 parts by weight of the rubber.

Oligomers: crow ether, fluorinated oligomer, polybutene, xylene resin, chlorinated rubber, polyethylene wax, petroleum resin, rosin ester rubber, polyalkylene glycol diacrylate, liquid rubber (polybutadiene, styrene-butadiene rubber, butadiene-acrylonitrile rubber, polychloroprene Various oligomers such as silicone-based oligomers and poly-α-olefins.

A preferred compounding ratio of the oligomer is 5 to 100 parts by weight based on 100 parts by weight of the rubber.

Lubricants: hydrocarbon lubricants such as paraffin and wax;
Higher fatty acids, fatty acid-based lubricants such as oxyresin acids, fatty acid amides, fatty acid amide-based lubricants such as alkylenebisfatty acid amides, fatty acid lower alcohol esters, fatty acid polyhydric alcohol esters, ester-based lubricants such as fatty acid polyglycol esters, fatty alcohols, Alcoholic lubricants such as polyhydric alcohols, polyglycols and polyglycerols,
Various lubricants such as metal soaps and mixed lubricants.

The preferred compounding ratio of the lubricant is 1 to 100 parts by weight of rubber.
5050 parts by weight.

In the present invention, natural materials such as bitumen and clay can be used as the viscoelastic material.

In the present invention, the damper 3 may have any configuration as long as it is mainly composed of the viscoelastic material as described above. For example, (A) a network structure, A composite formed of a viscoelastic material and at least one skeleton of a corrugated structure, a honeycomb-shaped structure, and a woven fabric.

(B) Spherical bodies, columnar bodies in the viscoelastic material, or partition members that form cells in the viscoelastic material (FIGS. 3 (a) to 3 (a)).
(As shown in (e)).

It can be.

In the case of the above (A), a specific configuration is, for example, a configuration manufactured as follows.

I The skeleton and the viscoelastic body are integrated under pressure.

II The skeletal body and the viscoelastic body are alternately stacked.

III A skeletal body and a viscoelastic body that are integrated under pressure are alternately stacked with the skeletal body and / or the viscoelastic body.

IV A plate-like material or a wire-like material is further combined with the material produced in the above I-III.

Further, the skeleton is any one of a net-like structure, a wavy structure, a honeycomb-like structure, and a woven fabric (for example, a stocking-like structure).
Although there is no particular limitation, natural fibers such as metals, ceramics, plastics, FRP, polyurethane, cotton and silk, and synthetic fibers such as polyamide and polyester can be used.

On the other hand, in the case of (B), the material of the solid substance such as a spherical body, a columnar body, or a cell-forming partition member is not particularly limited, but for example, metal, ceramics, glass, FRP, plastics, polyurethane, high-hardness rubber, Wood, rock, sand, gravel, etc. are suitable. In addition, a rubber material, paper, leather, or the like having relatively low hardness may be used for the partition member.

The partition members 8 shown in FIGS. 3 (a) to 3 (e) are all such that an aggregate of cells elongated in the vertical direction is formed on the soft body of the damper. The partition member 8 is provided concentrically, (b) is radial, (c) is a combination of (a) and (b), (d) is radial, and (e) is a spiral. 3 (a) to 3 (e), the outermost cylinder indicates the inner wall of the vulcanized rubber of the damper.

Examples of the rubber material include the unvulcanized rubber and the rubber material used for the vulcanized rubber.

Of course, in the present invention, the configuration of the damper is not limited to the above (A) and (B).

In addition, the seismic isolation structure of the present invention may be improved for covering the outer surface with a rubber material having excellent weather resistance for the purpose of improving the weather resistance and the like.

In this case, as the covering rubber material, a rubber-like polymer having excellent weather resistance is desirable, for example, butyl rubber, acrylic rubber, polyurethane, silicone rubber, fluorine rubber, polysulfide rubber, ethylene propylene rubber (ERP and EPDM),
Hypalon, chlorinated polyethylene, ethylene vinyl acetate rubber, epichlorohydrin rubber, chloroprene rubber, and the like. Of these, butyl rubber, polyurethane, ethylene propylene rubber, hypalone, chlorinated polyethylene, ethylene vinyl acetate rubber, and chloroprene rubber are particularly effective from the viewpoint of weather resistance. Further, in consideration of the adhesiveness with the rubber constituting the soft plate, butyl rubber, ethylene propylene rubber, and chloroprene rubber are desirable, and particularly, ethylene propylene rubber is most preferably used.

These rubber materials may be used alone or as a blend of two or more. Further, it may be blended with a commercially available rubber, for example, natural rubber, isoprene rubber, ethylene butadiene rubber, butadiene rubber, nitrile rubber or the like to improve elongation and other physical properties. Further, these rubber materials include various fillers, anti-aging agents, plasticizers, softeners,
A general compounding agent may be mixed with a rubber material such as oil.

In order to manufacture such a seismic isolation device of the present invention, for example, a hard plate and a soft plate are alternately laminated and vulcanized and formed into a seismic isolation rubber, or a hollow portion is formed in advance so that a central hollow portion is formed. Insert a preformed damper and low-elastic material into the hollow part of the sulfur-isolated rubber, or alternately insert a hard plate and a soft-plate material whose center is hollowed out into the preformed damper and low-elastic material A method of co-vulcanizing this is adopted.

[Effect of the Invention] Since the seismic isolation structure of the present invention has a damper effect together with the seismic isolation effect, the vibration at the time of the occurrence of the earthquake is absorbed by the seismic isolation structure, and the degree of the vibration transmitted to the building is reduced. Is reduced. For this reason, even when a large earthquake occurs, it is possible to prevent the building from colliding with other structures, or to damage equipment such as water pipes, gas pipes, and wiring. Moreover, the damping effect of the low elastic material interposed between the laminated rubber and the damper can effectively prevent the damper from interfering with the seismic isolation function in the case of minute vibration. An extremely excellent damping effect is exhibited in a wide range from deformation to large deformation.

It should be noted that the seismic isolation structure of the present invention can sufficiently expect excellent effects such as anti-vibration (anti-vibration, anti-vibration) in addition to the anti-seismic effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing a seismic isolation structure according to one embodiment of the present invention, and FIG. 2 is a stress-strain curve of a material. FIGS. 3A to 3E are perspective views each showing an example of a partition member. 1 ... seismic isolation structure, 2 ... laminated rubber, 3 ... damper, 4 ... low elastic material, 11 ... hard plate, 12 ... soft plate, 13, 14 ... flange.

Claims (1)

(57) [Claims] A hollow portion is provided in a laminated rubber obtained by alternately laminating a plurality of rigid plates having rigidity and soft plates having viscoelastic properties, and the hollow portion is mainly constituted by a viscoelastic material. A damper, and a material having lower elasticity than the damper is interposed between the damper and the inner wall of the cavity of the laminated rubber, wherein the viscoelastic material and the low elasticity material are , The storage modulus E dynamically measured at 25 ° C., 5 Hz and 0.01% strain is (However, E _V represents a storage elastic modulus E of the viscoelastic material, E _L is. Showing a storage modulus E of the low-elastic material) base-isolated structure which is a.