JPH011843A - Seismic isolation structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a seismic isolation structure for preventing the transmission of seismic force to equipment, structures, etc. This invention relates to an improved seismic isolation structure.

[Background Art and Prior Art] A structure (seismic isolation rubber) in which a plurality of steel plates and rubber plates are alternately laminated has recently attracted attention as a support member that satisfies vibration isolation properties during earthquakes.

When such seismic isolation rubber is interposed between a rigid building such as concrete and the foundation foundation, it is soft in the lateral direction, that is, has a small shear rigidity, so it can change the natural period of the building from the earthquake period. It has a shifting effect, which greatly reduces the acceleration that buildings receive from earthquakes.

A major feature of this type of seismic isolation rubber is that it undergoes elastic deformation to return to its original position after being deformed by an earthquake.Moreover, in order to minimize the sinking of the building due to the creep phenomenon of the seismic isolation rubber, Furthermore, the energy absorption capacity (fA damping effect) of the seismic isolation rubber itself is extremely small. For this reason, conventionally, seismic isolation rubber has been constructed using a rubber material that has a small hysteresis loss as a material characteristic.

However, with such a seismic isolation system that uses only low-attenuation seismic isolation rubber, the slow lateral sway of the building during an earthquake remains for a long time even after the earthquake subsides, so if the amount of lateral sway is large, In addition to damage to the seismic isolation rubber itself,
There is a risk of collision between the building and other structures and destruction of equipment such as wood pipes, gas pipes, and wiring.

Conventionally, in order to reduce this rolling displacement as quickly as possible, a method has been adopted in which a plastic damper made of a soft metal or the like that undergoes plastic deformation immediately upon application of an earthquake force is used in combination.

For example, by creating a hollow part inside the seismic isolation rubber, filling this part with lead, and using plastic deformation during an earthquake to impart a damping effect to the seismic isolation rubber, the seismic isolation effect and the damper (damping effect) can be created. ) is proposed.

However, in such a seismic isolation device, although the seismic energy absorption function is increased, a new resonance phenomenon occurs in the high frequency region due to the high elasticity of the plastic damper.

In addition, when using seismic isolation rubber containing lead, when the seismic isolation rubber is greatly deformed during a major earthquake, the hard steel plate will damage the lead, and the damaged lead will further damage soft plates such as rubber, so the seismic isolation rubber It is easy to cause the entire structure to break.

Furthermore, damaged lead easily breaks due to repeated large deformations.

The present invention solves the above-mentioned conventional problems and provides an improved seismic isolation device that has both a seismic isolation effect and a damping effect. We have previously applied for a patent for a seismic isolation device characterized by a seismic isolation rubber bonded together and a damper made of plastic installed in parallel, for example, a seismic isolation device with a damper built into the seismic isolation rubber. (Special application 1986-
No. 217689. Hereinafter 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 performance in small to large deformations, but has the disadvantage that it is ineffective in damping minute vibrations. There is.

[Means for Solving the Problems] The present invention provides a seismic isolation structure that exhibits excellent damping properties from small to large deformations, and can also exhibit excellent effects against minute vibrations. It is something to do.

The seismic isolation structure of the present invention has a cavity in a laminated rubber made by alternately laminating a plurality of hard plates having rigidity and soft plates having viscoelastic properties, and a viscoelastic material is provided in the cavity. It is characterized in that a damper is mainly arranged, 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.

[Function] As mentioned above, the inventors of the present invention solved the conventional problems and conducted repeated research on a seismic isolation device that has both a seismic isolation effect and a damping effect. By arranging a specific viscoelastic material with excellent hysteresis characteristics as a damper, we were able to obtain a seismic isolation structure with extremely high attenuation over a wide range of deformations, from small to large.

However, in this case, the more the damping properties of even the above-mentioned specific viscoelastic material are increased, the higher the elastic modulus becomes than that of the surrounding seismic isolation rubber during minute deformations. Of course, the rate of increase is much smaller than that of plastic bodies made of lead or steel, but in order to exhibit high loss properties, it is generally necessary to have a high modulus of elasticity.

By the way, modern society requires countermeasures against micro-vibration for IC factories, pioneering plants, laser factories, railways, houses along roads, etc. that require precision processing. In the case of general seismic isolation rubber, since its modulus of elasticity in the lateral direction is low, it exhibits a vibration isolation effect even against these minute vibrations, and exhibits an excellent vibration damping effect.

However, as mentioned above, in the case of seismic isolation rubber in which a viscoelastic material is arranged, the elastic modulus of this viscoelastic material is high at minute displacements, so as a result, the elastic modulus of the seismic isolation structure is lower than that of a general case without a viscoelastic material. Higher than seismic isolation rubber.

For this reason, the damping effect against minute vibrations tends to decrease, making it impossible to satisfy the current required characteristics.

Therefore, the present inventors have developed a method for dealing with minute vibrations in this way.
In order to prevent the damper from interfering with the damping action of the seismic isolation rubber, we conducted further studies and decided to place a low elastic material as an IIN material between the laminated rubber of the seismic isolation rubber and the built-in damper. The inventors have discovered that such ultraviolet effects can be effectively prevented, and have completed the present invention.

[Example] Examples will be described below with reference to the drawings.

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

As shown in FIG. 1, the base isolation structure 1 of this embodiment is a laminated cylindrical structure made by alternately bonding a plurality of hard plates 11 with rigidity and soft plates 12 with viscoelastic properties. rubber 2
A cylindrical space is provided in the center of the cylindrical space, and a damper 3 mainly made of a viscoelastic material is disposed within this space, and between the damper 3 and the inner wall of the cavity of the laminated rubber 2, there is a space larger than the damper. A low elastic material (hereinafter sometimes referred to as "low elastic material") 4 is interposed therebetween. In addition, in the figure,
Reference numerals 13 and 14 are flanges, 20 is a building, and 30 is a foundation.

In the present invention, the shape of the Ut layer rubber 2, the shape of its cavity, 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 in any way; A columnar body is suitable for this.

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

However, if necessary, a part of this low elasticity material portion may be replaced with a space.

In addition, in the seismic isolation structure 1 shown in FIG. 1, there are no particular restrictions on the size of the laminated rubber 2, the size of the damper 3, the thickness of the low elastic material 4, etc., and the use of the seismic isolation structure is Although it is appropriately selected depending on the purpose, for example, the ratio of the diameter of the cavity of the laminated rubber to the diameter of the laminated rubber, It/L, is □≦0, 80, preferably β □≦0.70, more preferably It is desirable that □≦0.64.

Also, the ratio between the thickness ILo of the low elastic material 4 and the diameter 1 of the cavity of the laminated rubber 2, °C. /L is preferably .

Below, the laminated rubber 2 and damper 3 of the seismic isolation structure of the present invention will be described.
and the constituent materials of the low elastic material 4 will be explained.

As the material of the hard plate 11 of the laminated rubber 2, metal, ceramics, plastics, FRP, polyurethane, wood, paper board, slate board, decorative board, etc. can be used. The soft board 12 may be made of various vulcanized rubbers, organic materials such as plastics, foams thereof, asphalt,
Various materials such as inorganic materials such as clay and mixed materials thereof can be used. These hard plates 11 and soft plates 1
The shape of 2 may be a circle, a square, or a polygon such as a pentagon or a hexagon.

On the other hand, the viscoelastic material that is the main constituent material of the damper 3 has a hysteresis ratio (hs
. ) is 0.2 or more, preferably 0.3 or more. In addition, at a tensile speed of 200 mm/min, hl
io is given by the area ratio of stress ABHO in FIG.

Further, the elastic modulus of the viscoelastic material is at a frequency of 5 Hz.

Storage modulus E measured dynamically at 25°C at 0.01% strain
It is desirable that the value of is 1≦E≦2X t o'(kg/cm"), preferably 5≦E≦1x t o' (kg/cm2).

In addition, the elongation of viscoelastic materials at tensile breakage is 1%.
The content is preferably at least 5%, more preferably at least 10%, particularly preferably at least 20%.

Therefore, as the low elastic material 4, 25°C, 5Hz, O
, For the storage modulus E measured dynamically at % strain,
E of the low elastic material is EL% If E of the above viscoelastic material is Ev, it is preferably Ev.

The low elasticity material 4 may be any material that satisfies the above characteristics, such as various rubbers, plastics,
In addition, among the viscoelastic materials mentioned below, those having the above characteristics can be used. Further, as the low elasticity material, a foam, a spring body made of metal, plastic, rubber, etc., a blanket, a woven fabric, a wall sack, etc. can also be used. The low modulus material layer may be partially empty if desired.

In the present invention, examples of the viscoelastic material of the damper include unvulcanized rubber and vulcanized rubber having the above-mentioned properties, resins and plastic substances having the above-mentioned properties, and the like.

In the present invention, the viscoelastic material is preferably unvulcanized rubber, vulcanized rubber, or similar substances having the above-mentioned hysteresis ratio and elastic modulus characteristics, such as ethylene propylene rubber (EPR, EPDM). , nitrile rubber (NBR), butyl rubber, halogenated butyl rubber, chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SB
R), general rubbers such as butadiene rubber (BR), acrylic rubber, ethylene-vinyl acetate rubber (EVA), polyurethane, special rubbers such as silicone rubber, fluororubber, ethylene acrylic rubber, polyester elastomer, epichlorohydrin rubber, chlorinated polyethylene, Alternatively, thermoplastic elastomers and the like can be mentioned. In addition, when the viscoelastic material is unvulcanized rubber, Mooney viscosity ML at 100°C.

It is preferable that 4 is 10 or more.

These rubber materials may be used alone or in combination of two or more. In addition, these rubber materials are mixed with common compounding agents for rubber materials such as various fillers, tackifiers, lubricants, anti-aging agents, plasticizers, softeners, low molecular weight polymers, oils, etc. Hardness, loss characteristics, and durability can also be added depending on the purpose. In particular, in order to maintain specified performance over a long period of time, appropriate stabilizers such as anti-aging agents, polymerization inhibitors, and scorch inhibitors are added to the above rubber materials, or the polymer itself is hydrogenated or otherwise modified. It is extremely effective to achieve stabilization by

In addition, when adhering the viscoelastic material and other constituent materials,
Generally, it is advantageous to use adhesion using the tackiness of a viscoelastic material, but for adhesion using this tackiness, it is also possible to introduce a network of necessary chemical or physical bonds into the bonded portion.

As the viscoelastic material of the present invention, in addition to unvulcanized rubber and vulcanized rubber having the above characteristics, the following substances having the above characteristics can also be used.

For example, polystyrene, polyethylene, polypropylene, ABS, polyvinyl chloride, polymethyl methacrylate,
Thermoplastic plastics such as polycarbonate, polyacetal, nylon, chlorinated polyether, polytetrafluoroethylene, acetyl cellulose, and ethyl cellulose, and the following fillers as necessary for these plastics:
Examples include those containing plasticizers, softeners, tackifiers, oligomer lubricants, etc.

■ Fillers: Scale-like inorganic fillers such as clay, diatomaceous earth, carbon brush, silica, talc, barium sulfate, calcium carbonate, magnesium carbonate, metal oxides, mica, graphite, aluminum hydroxide, various metal powders,
Wood chips, glass powder, ceramic powder, granular or powder solid fillers such as granular or powdered polymers, and various other natural or artificial short fibers and long fibers (e.g., straw, hair, glass fiber, metal fiber, and other various types) Fillers for rubber or resin, such as polymer fibers, etc.

The blending ratio of filler is 30 to 2 parts by weight per 100 parts by weight of rubber.
The amount is preferably 50 parts by weight.

In addition, as short fibers, general short fibers such as glass, plastic, and natural products are used. These short fibers also include special short fiber reinforcements such as: For example, the blending state of short fibers is a reinforced rubber in which short fibers of a thermoplastic polymer having 10-NH- groups in the molecule are grafted to vulcanizable rubber via an initial condensate of phenol formaldehyde resin. It is preferable to use a composition in which short fibers are chemically bonded to rubber. The fine short UA fibers of the thermoplastic polymer have a melting point of 190 to 235°C,
Preferably 190-225°C, particularly preferably 200°C
In polymer molecules such as nylons such as nylon 6, nylon 610, nylon 12, nylon 611, and nylon 612, polyureas such as polyhebutamethylene urea and polyundecamethylene urea, and polyurethanes, which have a temperature of ~220°C.
It is preferably formed from a thermoplastic polymer having CONH groups, especially nylon, and has an average diameter of 0.05 to 0.
．． It is preferable that the fiber has a diameter of 8 μm, a circular cross section, a shortest fiber length of preferably 1 μm or more, and is embedded in the form of fine short fibers with molecules arranged in the fiber axis direction.

■ Softeners: Softeners for various rubbers or resins, such as aromatic, naphthene, and paraffin.

The preferred blending ratio of the softener is 5 to 150 parts by weight per 100 parts by weight of rubber.

■Plasticizers: Various ester plasticizers such as phthalate esters, phthalate mixed group esters, aliphatic dibasic acid esters, glycol esters, fatty acid esters, phosphate esters, stearate esters, epoxy plasticizers, and their plastics. or plasticizers for NBR such as phthalate, adipate, sebacate, phosphate, polyether, and polyester.

The preferred blending ratio of the plasticizer is 5 to 150 parts by weight per 100 parts by weight of rubber.

■ Tackifiers: Various tackifiers (tackifiers) such as coumaron resin, coumaron-indene resin, phenol terpene resin, petroleum hydrocarbons, and rosin derivatives.

The preferred blending ratio of the tackifier is 1 to 5 parts by weight per 100 parts by weight of rubber.

■ Oligomers: Klawetyl, fluorine-containing oligomers, polybutene, xylene resin, chlorinated rubber, polyethylene wax, petroleum resin, rosin ester rubber, polyalkylene gelicol diacrylate, liquid rubber (polybutadiene, styrene-butadiene rubber, butadiene-acrylonitrile rubber, polyester) chloroprene, etc.), silicone oligomers, poly-α-olefins, and other oligomers.

The preferred blending ratio of the oligomer is 5 to 100 parts by weight per 100 parts by weight of rubber.

■ Lubricants: Hydrocarbon lubricants such as paraffin and wax, fatty acid lubricants such as higher fatty acids and oxyfatty acids, fatty acid amide lubricants such as fatty acid amide and alkylene bis fatty acid amide, fatty acid lower alcohol esters, fatty acid polyhydric alcohol esters, and fatty acids. Various lubricants such as ester lubricants such as polyglycol esters, alcohol lubricants such as fatty alcohols, polyhydric alcohols, polyglycols, and polyglycerols, metal soaps, and mixed lubricants.

The preferred blending ratio of the lubricant is 1 to 100 parts by weight of rubber.
~50 parts by weight.

In the present invention, natural products such as bitumen and clay can also 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, but for example, (A) a network structure; A composite of a skeleton of at least one of a wavy structure, a honeycomb structure, and a fabric, and a viscoelastic material.

(B) A partition member that forms a spherical body, a columnar body, or a cell in a viscoelastic material (Fig. 3 (a)
~ those shown in (e)) are enclosed in a solid substance.

It can be done.

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

■ Integrate the skeletal body and the viscoelastic body under pressure.

11 Alternately stack the skeletal body and the viscoelastic body.

Ill A skeleton body and a viscoelastic body are integrated under pressure and are alternately stacked on the skeleton body and/or the viscoelastic body.

! ■ Above! -It is combined by further laminating a plate-like material or a wire-like material to what is produced in III.

In addition, the skeleton may be any one of a net-like structure, a wave-like structure, a honeycomb-like structure, and a fabric (for example, a stocking-like structure), but there are no particular restrictions on the material of these skeletons. , metals, ceramics, plastics, FRP, polyurethane, natural fibers such as cotton and silk, and synthetic fibers such as polyamide and polyester.

On the other hand, in the case of (B), the material of the solid substance such as the spherical body, columnar body, or cell forming partition member is not particularly limited, but examples include metal, ceramics, glass, FRP, plastics, polyurethane, high hardness rubber, Suitable materials include wood, rocks, sand, gravel, etc. In addition to these materials, the partition member may also be made of a rubber material with relatively low hardness, paper, leather, or the like.

Note that the partition members 8 shown in FIGS. 3(a) to 3(e) all form an aggregate of vertically elongated cells in the soft body of the damper, and (a) The partition members 8 are provided concentrically, (b) radially, (C) a combination of (a) and (b), (d) radially, and (e) spirally. In FIGS. 3(a) to 3(e), the outermost cylinder represents the inner wall of the vulcanized rubber of the damper.

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

Of course, in the present invention, the structure of the damper is the above (A),
It is not limited to (B). - The seismic isolation structure of the present invention can be improved by coating the outer surface with a rubber material having excellent weather resistance, etc., for the purpose of improving its weather resistance.

In this case, the coating rubber material is preferably a rubbery polymer with excellent weather resistance, such as butyl rubber, acrylic rubber, polyurethane, silicone rubber, fluororubber, polysulfide rubber, ethylene propylene rubber (ERP and EPDM).
), Hypalon, chlorinated polyethylene, ethylene vinyl acetate rubber, epichlorohydrin rubber, chloroprene rubber, etc. Among these, butyl rubber, polyurethane, ethylene propylene rubber, Hypalon, chlorinated polyethylene, ethylene vinyl acetate rubber, and chloroprene rubber are particularly effective in terms of weather resistance. Furthermore, in consideration of adhesion to the rubber constituting the soft plate, butyl rubber, ethylene propylene rubber, and chloroprene rubber are preferable, with ethylene propylene rubber being most preferable.

Even if these rubber materials are used alone, 2f! You may use a blend of the above. Further, in order to improve elongation and other physical properties, it may be blended with commercially available rubbers such as natural rubber, isoprene rubber, ethylene butadiene rubber, butadiene rubber, nitrile rubber, etc. Furthermore, these rubber materials contain various fillers, anti-aging agents, plasticizers, softeners,
General compounding agents such as oil may be mixed with rubber materials.

In order to manufacture such a seismic isolation device of the present invention, for example,
A damper and a damper are pre-molded into the hollow part of the seismic isolation rubber which has been vulcanized and molded by laminating hard plates and soft plates alternately, or by hollowing out the seismic isolation rubber which has been vulcanized and molded by laminating hard plates and soft plates in advance. A method is adopted in which an elastic material is inserted, or a hard plate with a hollowed out center and a soft plate material are alternately sandwiched between a pre-formed damper and a low elastic material and then co-vulcanized.

[Effects of the Invention] Since the base isolation structure of the present invention has a damper effect as well as a base isolation effect, shaking when an earthquake occurs is absorbed by the base isolation structure, and the degree of shaking transmitted to the building is reduced. reduced. Therefore, even in the event of a major earthquake, buildings are prevented from colliding with other structures, and valuable items such as wood pipes, gas pipes, and wiring are prevented from being destroyed. Moreover, the 1yi-gauge effect of the low-elasticity material interposed between the fJt layer rubber and the damper can effectively prevent the damper from limiting its seismic isolation effect in the case of minute vibrations. ,
Extremely excellent damping effects are exhibited in a wide range of areas from no deformation to large deformation.

In addition, the seismic isolation structure of the present invention can be fully expected to have excellent effects such as vibration isolation (vibration isolation, vibration suppression) in addition to the seismic isolation effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing a base isolation structure according to an embodiment of the present invention, and FIG. 2 is a stress-strain curve of the material. Figure 3 (a
) to (e) are perspective views each showing an example of a partition member. 1... Seismic isolation structure, 2... Laminated rubber, 3
...damper, 4...low elasticity material, 1
1...Hard board, 12...Soft board, 13
．． 14...Flange. Agent Patent Attorney Tsuyoshi Shigeno

Claims (1)

[Claims] (1) A cavity is provided in a laminated rubber made by alternately laminating a plurality of rigid plates with rigidity and soft plates with viscoelastic properties, and a damper mainly made of viscoelastic material is provided in this cavity. What is claimed is: 1. A seismic isolation structure characterized in that a material having lower elasticity than the damper is interposed between the damper and a cavity inner wall of the laminated rubber.