JPH0754132B2 - Seismic isolation device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a seismic isolation device for preventing transmission of seismic force to devices and structures, and in particular to an improvement having both seismic isolation effect and damping effect. Seismic isolation device.

[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 bearing member that satisfies the vibration damping property during an earthquake.

This type of seismic isolation rubber inserts a seismic isolation rubber that is laterally soft, that is, has a low shear rigidity, between a rigid building such as concrete and the foundation, so that the natural period of a concrete building is Has the effect of shifting from the cycle,
Due to this action, the acceleration that the building receives due to the earthquake becomes extremely small.

This type of seismic isolation rubber is characterized by returning to its original position (elastic deformation) again after deformation due to an earthquake, and in order to minimize the settlement of the building due to the creep phenomenon of the seismic isolation rubber. Moreover, the energy absorption capacity (damping effect) of the seismic isolation rubber itself is extremely small. Therefore, conventionally, the seismic isolation rubber has been configured by using a rubber material having a small hysteresis loss as its material property.

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

Therefore, in order to reduce the rolling displacement as quickly as possible, a method of using a plastic damper made of a soft metal or the like that immediately plastically deforms when an earthquake force is applied is used. For example, by hollowing out the inside of the seismic isolation rubber, embedding lead in this part, and using the plastic deformation of lead during an earthquake to give a damping effect to the seismic isolation rubber, seismic isolation effect and damper effect (damping effect) ) Has been proposed.

[Problems to be solved by the invention] However, in such a seismic isolation device, although the seismic energy absorbing function is increased, a new co-seismic phenomenon due to the high elasticity of the plastic damper is applied to the high frequency region. It appears and is not preferable as a seismic isolation device.

In addition, the method of installing the seismic isolation rubber and the damper together makes the installation work complicated, which leads to a significant increase in cost and is not an advantageous method.

In the case of lead-containing seismic isolation rubber, when the seismic isolation rubber is largely deformed in the event of a large earthquake, a hard plate such as a steel plate damages lead, and the damaged lead damages a soft plate such as rubber. It is easy to cause the entire break. Moreover, the damaged lead is easily broken by repeated large deformation.

[Means for Solving the Problems] In order to solve the above problems, the seismic isolation device of the present invention includes a seismic isolation rubber made of a normal low-damping rubber that has been conventionally used as a seismic isolation rubber material, Seismic isolation rubber made of damping rubber is installed in parallel, the vertical damping force is mainly supported by the damping rubber made of low damping rubber, and the damping force in the horizontal direction is mainly made by the damping rubber made of high damping rubber. By carrying it, it is configured to have both a seismic isolation effect, a damping effect, and creep resistance.

That is, the present inventors have solved the drawbacks of the conventional seismic isolation rubber,
Displacement restoring force, repeated durability,
As a result of comprehensive examination of manufacturing cost, maintenance, etc., it was judged that the best method is to utilize the high damping property (high hysteresis property) of the rubber itself. On the other hand, as a result of diligent study on the method of extracting the maximum damping effect from a specific rubber material, it is preferable to use a structure in which the rubber itself deforms to the maximum when an earthquake occurs, that is, a rubber-hard plate laminated structure. Was found, a high damping base isolation rubber in which a plurality of high hysteresis rubber materials and a plurality of hard plates such as steel plates were alternately laminated was applied for a patent.

By the way, in this highly damped seismic isolation rubber, a material having a large hysteresis loss is preferable when only considering the action as a damper. However, when the hysteresis loss increases, creep increases, and the temperature dependence of the elastic modulus increases, which causes undesirable side effects for a seismic isolation device that supports a building. Therefore, as a result of further studies, basically, a conventional low damping seismic isolation rubber was installed in parallel with this high damping seismic isolation rubber, and the low damping seismic isolation rubber supports part or all of the vertical load. By designing
They have found that this problem can be solved and completed the present invention.

That is, the seismic isolation device of the present invention, by the high-damping seismic isolation rubber described later, while exhibiting the damping properties required as a seismic isolation device,
A conventional low-damping seismic isolation rubber is used to support a part or all of the vertical load of a building or equipment so that creep can be kept below a predetermined level.

[Operation] In the present invention, the highly damped seismic isolation rubber exhibits a good damping property due to an excellent damping effect together with the seismic isolation effect. On the other hand, the low damping seismic isolation rubber exhibits good creep resistance together with the seismic isolation effect.

Therefore, according to the seismic isolation device of the present invention, the sway transmitted to the building is alleviated, and the building can be supported stably and reliably for a long period of time.

Embodiments Embodiments will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view showing a state where a seismic isolation device 1 according to an embodiment of the present invention is installed between a building 2 and a base 3.

As shown in FIG. 1, the seismic isolation device 1 of the present invention has a structure in which a high damping seismic isolation rubber 4 and a low damping seismic isolation rubber 5 are installed in parallel. In the figure, 6, 7, 8 and 9 are flanges. In the present invention, the seismic isolation rubbers 4 and 5 are both rubber plates 11 and 13.
And hard plates 12 and 14 having rigidity such as steel plates are alternately laminated.

In the seismic isolation apparatus of the present invention, the high damping base isolation rubber 4 and the low damping base isolation rubber 5 are installed in parallel at what ratio (number, sectional area, etc.) or the hard plates 12, 14 are installed. What is the value of the lamination ratio between the rubber plate 11 and the rubber plate 11, 13 is, for the seismic isolation performance required for the structure or equipment in which the device is actually installed, the spring constant, the damping effect, the creep performance, It is determined in consideration of the temperature dependence of the spring constant.

In the present invention, the high damping rubber used for the rubber plate 11 of the high damping base isolation rubber 4, that is, the high hysteresis rubber is
Hysteresis ratio h ₁₀₀ at 100% tensile deformation at ℃ is 0.25 to 0.7
0, storage modulus E (-10) at 10 ° C and 30 ° C at 5Hz, 0.01% deformation, ratio of E (30) E (-10) / E (3
It is preferable that 0) is a material satisfying 1.0 to 3.0.

On the other hand, the low damping rubber used for the rubber plate 13 of the low damping base isolation rubber 5, that is, the low hysteresis rubber is
Hysteresis ratio h ₁₀₀ of the tensile deformation is a 0.05 to 0.20, 5 Hz, -10 ° C. at 0.01% deformation, the storage elastic modulus E (-10) at 30 ° C., the ratio E of E (30) (-10) / E (30) is 1.
A material satisfying 0 to 1.5 is preferable.

The reason for the preferable range of the above characteristics will be described below.

Material Hysteresis Ratio In general, loss tangent tan δ is used as a measure of material hysteresis loss characteristics and damping characteristics. However, as is well known, tan δ is a quantity measured as a response delay to a stimulus with a small amplitude in the material, and when the material is 100 to 2
It is unsuitable as a parameter to describe the hysteresis loss characteristics of materials used for base-isolated rubber that undergoes large deformation of up to 00%.

Therefore, in the present invention, the hysteresis ratio (h ₁₀₀ ) of the material at 25 ° C. and 100% tensile deformation is used as the measure of loss characteristics. In addition, at a tensile speed of 200 mm / min, h ₁₀₀ is the stress-strain curve in FIG. Is given by the area ratio of.

It is desirable that h ₁₀₀ is as large as possible for the damper (damping) effect as described above, but this inevitably increases the plastic deformation of the material. Therefore, as the high hysteresis rubber material, it is desired that the range of h ₁₀₀ at 25 ° C. is preferably 0.25 ≦ h ₁₀₀ ≦ 0.70, more preferably 0.30 ≦ h ₁₀₀ ≦ 0.65.

On the other hand, as a low hysteresis rubber material,
It is desirable that the range of h ₁₀₀ is 0.05 ≦ h ₁₀₀ ≦ 0.20.

Temperature dependence of elastic modulus of material As is well known, the most important effect on seismic isolation characteristics is
Vertical spring constant and horizontal spring constant of the base isolation structure, which are directly proportional to the elastic modulus of the material.

On the other hand, looking at the usage status of seismic isolation rubber, it is generally used in a state where it is always exposed to the outside air. It is highly conceivable that the environmental conditions will be -10 ℃ in winter and 30 ℃ in summer. In response to such a situation, the rubber material or the like shows a temperature dependence of the elastic modulus to a greater or lesser degree, and tends to become hard at a low temperature. Furthermore, as the amount of material loss increases, the temperature dependence tends to increase.

In the present invention, the temperature dependence of the elastic modulus of the material is, for high hysteresis rubber, the value E (-10) of the storage elastic modulus E dynamically measured at 5 Hz and 0.01% strain at -10 ° C. 30
The ratio with the value E (30) at ℃ is Preferably On the other hand, for low hysteresis rubber, Is desirable.

As the high hysteresis rubber material used in the present invention, any material may be used as long as it satisfies the above-mentioned characteristics.
R, EPDM), nitrile rubber (NBR), butyl rubber, halogenated butyl rubber, chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber (BR), etc. 15 parts by weight of cyclopentadiene resin or dicyclopentadiene resin to 100 parts by weight of rubber composed of one or more kinds of
A mixture obtained by mixing 100 parts by weight and vulcanized is preferably used because it has excellent fracture properties and excellent adhesion to a metal.

In addition, various fillers, plasticizers, softeners,
You may mix | blend normally used compounding agents, such as oil.

On the other hand, as the low hysteresis rubber material, any rubber can be used as long as it satisfies the above-mentioned characteristics.

In the present invention, as the material of the hard plates 12 and 14, metal such as steel, ceramics, plastics, FRP, polyurethane, wood, paper plate, slate plate, and decorative plate can be used.

Further, the shapes of the rubber plates 11 and 13 and the hard plates 12 and 14 may be circular, rectangular, polygonal such as pentagonal and hexagonal.

To bond such a rubber plate and a hard plate, an adhesive may be used or co-vulcanization may be performed.

Since the seismic isolation rubber is constantly exposed to the outside air during use, it is subject to long-term deterioration due to air, humidity, ozone, ultraviolet rays, radiation for nuclear power, and sea breeze at seaside. Further, since it supports the building, it is constantly subjected to a compressive load, and even under normal conditions, a considerable tensile stress is applied to the surface portion of the rubber layer. Moreover, the rubber layer is locally subjected to 100-200% tensile strain during a large earthquake. However, deterioration progresses further due to such tensile stress and tensile strain.

Therefore, in both the high damping seismic isolation rubber 4 and the low damping seismic isolation rubber 5, as shown in FIG. 3, the outer circumference of the seismic isolation rubber 4 (or 5) is made of a rubber material or the like having excellent weather resistance. It is preferable to coat with the coating layer 15.

As the rubber material of the coating layer 15, a rubber-like polymer having excellent weather resistance is desirable, and for example, butyl rubber, acrylic rubber, polyurethane, silicone rubber, fluororubber, polysulfide rubber, ethylene propylene rubber (FRP and EPDM), hypalon. , Chlorinated polyethylene, ethylene vinyl acetate rubber, epichlorohydrin rubber, chloroprene rubber and the like. Of these, butyl rubber, polyurethane, ethylene propylene rubber, hypalon, chlorinated polyethylene, ethylene vinyl acetate rubber, and chloroprene rubber are particularly effective from the viewpoint of weather resistance. Further, the rubber plates 11 and 13
Considering the adhesiveness with the rubber constituting the rubber, butyl rubber, ethylene propylene rubber, and chloroprene rubber are preferable, and ethylene propylene rubber is most preferably used.

These rubber materials may be used alone or in combination of two or more. Further, in order to improve elongation and other physical properties, it may be blended with a commercially available rubber such as natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber and the like. Further, these rubber materials may be mixed with various fillers, antioxidants, plasticizers, softeners, oils and other compounds commonly used in rubber materials.
In particular, by adding cyclopentadiene or dicyclopentadiene resin in an amount of 10 to 40 parts by weight and 100 parts by weight of a rubber material, and further adding 5 to 20 parts by weight of a rosin derivative, the breaking property and the adhesion to a metal can be significantly Improved and highly advantageous. In this case, as the rosin derivative, the main components are abietic acid, pimaric acid and a mixture of carboxylic acids having a similar structure to various rosin-based esters, polymerized rosin, hydrogenated rosin, cured rosin, hyrosin, resin acid. Examples thereof include zinc and modified rosin.

The thickness of the coating layer 15 formed of such a rubber material is generally preferably thicker, as the internal protection effect is higher,
On the other hand, there are problems such as high cost and delayed vulcanization. Therefore, the coating layer 15 has a thickness of 1 to
It is preferably 30 mm, desirably 2 to 20 mm, especially 3 to 15 mm. However, if the seismic isolation device is required to have fire resistance, the coating layer can have a thickness of more than 30 mm.

It is important that the coating layer 15 is firmly adhered to the hard plates 12 and 14 and the rubber plates 11 and 13, but the adhesion is sometimes referred to as a rubber material of the rubber plates 11 and 13 (hereinafter, referred to as “internal rubber”). ) And the rubber material of the coating layer 15 (hereinafter referred to as “coated rubber”)
There is a thing. ) And vulcanization adhesion of and.

A two-stage vulcanization bonding method in which only the internal rubber is vulcanized first and then the coated rubber is vulcanized and bonded.

A method of vulcanizing the internal rubber and the coated rubber separately and then bonding them with an adhesive.

It can be done easily. At the time of adhesion, if the adhesion between the internal rubber and the covering rubber is poor, a third rubber layer having good adhesiveness with respect to both may be interposed therebetween. Further, an additive for improving adhesiveness may be blended with the internal rubber and / or the coated rubber.

The seismic isolation device described with reference to FIG. 1 or 3 is an embodiment of the present invention, and the present invention is not limited to the illustrated one.

For example, the high-damping seismic isolation rubber and the low-damping seismic isolation rubber are not limited to being installed in parallel as shown in FIG. 1, but both seismic isolation rubbers may be integrated.

[Effects of the Invention] As described in detail above, the seismic isolation device of the present invention has both a seismic isolation effect and a damper effect. Therefore, the seismic vibration at the occurrence of an earthquake is absorbed by the seismic isolation structure and is transmitted to the building. The degree is reduced. Therefore, even when a large earthquake occurs, it is possible to prevent the building from colliding with other structures and the damage of equipment such as water pipes, gas pipes, and wiring.

In addition to the seismic isolation effect, the seismic isolation device of the present invention can sufficiently expect excellent effects such as vibration removal (vibration prevention and vibration suppression).

[Brief description of drawings]

FIG. 1 is a sectional view showing a seismic isolation device according to an embodiment of the present invention,
FIG. 2 is a graph showing a stress-strain curve of the material, and FIG. 3 is a vertical sectional view of a seismic isolation rubber according to another embodiment of the present invention. 1 …… Seismic isolation device, 4 …… High damping seismic isolation rubber, 5 …… Low damping seismic isolation rubber, 15 …… Coating layer.

Claims (2)

[Claims] 1. A seismic isolation device that supports a vertical load and elastically deforms in a horizontal direction. A low-damping laminated rubber that mainly supports a vertical load, and a high-damping rubber that mainly bears a horizontal damping force. A seismic isolation device characterized by installing laminated rubber in parallel. 2. The seismic isolation device according to claim 1, wherein the laminated rubber is formed by alternately laminating hard plates and rubber plates.