JP2005256365A - Rubber supporter for bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber supporter having the small temperature dependency of an equivalent stiffness without deteriorating damping characteristics within the range of -10°C to 40°C of an environmental temperature. <P>SOLUTION: In the rubber supporter for the bridge, hard boards having a stiffness and rubber layers are laminated alternately, a damping factor (heq) is kept within a range of 0.04≤heq≤0.1 within the range of -10°C to 40°C of an environmental temperature and the rate of change (R) of the equivalent stiffness shown by formula (1) is kept within the range of R≤0.25. It is preferable that carbon black and silica are blended with the rubber layer at a ratio of äthe quantity of silica blended (mass)/the quantity of carbon black blended (mass)}≥0.15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rubber bearing for a bridge suitable for supporting a bridge.

  In general, a structure in which a hard plate such as a steel plate and a rubber layer mainly composed of a viscoelastic rubber material are alternately laminated is widely used as a rubber support for supporting a bridge. This rubber bearing body for bridges is not only required to have excellent damping characteristics to attenuate the vibration of the bridge, but also the bridge can be installed in a natural environment from low temperature below freezing to over 30 ° C. For this reason, it is desired that the temperature dependence of the equivalent rigidity is small.

Conventionally, in order to improve the temperature dependency, a predetermined amount of carbon black is blended (Patent Document 1), a predetermined amount of silica is blended (Patent Document 2), or the amount of sulfur is increased. Various methods have been studied. However, when these methods are used to improve the temperature dependence, there is a problem that the attenuation characteristic is lowered.
JP 2002-340088 A JP 7-126437 A

  An object of the present invention is to provide a rubber bearing body having a low temperature dependency of equivalent rigidity without deteriorating damping characteristics in an environmental temperature range of −10 ° C. to 40 ° C.

(2) 前記ゴム層に、カーボンブラックおよびシリカが、｛シリカの配合量（質量）／カーボンブラックの配合量（質量）｝≧0.15の割合で配合されている(1)記載の橋梁用ゴム支承体。
(3) 前記ゴム層のゴム成分100質量部に対して、前記カーボンブラックが50質量部以下の割合で配合されている(2)記載の橋梁用ゴム支承体。 In order to solve the above problems, a rubber bearing body for a bridge according to the present invention has the following configuration.
(1) A rubber bearing in which rigid hard plates and rubber layers are alternately laminated, and the damping constant (heq) is in the range of 0.04 ≦ heq ≦ 0.1 in the environmental temperature range of -10 ° C to 40 ° C. A rubber bearing body for a bridge, characterized in that the rate of change (R) in equivalent stiffness represented by the following formula is in a range of R ≦ 0.25.

(2) The rubber bearing for a bridge according to (1), wherein carbon black and silica are blended in the rubber layer in a ratio of {silica blending amount (mass) / carbon black blending amount (mass)} ≧ 0.15. body.
(3) The bridge rubber bearing body according to (2), wherein the carbon black is blended at a ratio of 50 parts by mass or less with respect to 100 parts by mass of the rubber component of the rubber layer.

  As described above, the damping constant (heq) and the change rate of equivalent stiffness (R) in the range of ambient temperature -10 ° C to 40 ° C are in the above range, the rubber bearing body for bridges of the present invention has a reduced damping characteristic. Therefore, it can be used in an environment exposed to a wide temperature range from a low temperature to a high temperature because it is within the range required for the rubber bearing body for bridges and the temperature dependence of the equivalent rigidity is small.

  The rubber support of the present invention that can be used in an environment exposed to a wide temperature range as described above, for example, contains not only carbon black but also silica in the rubber layer, and further, the mixing ratio of carbon black and silica is described above. It is obtained by adjusting to a predetermined range. Therefore, it has the damping characteristics required for a rubber bearing body for bridges and has a large temperature change without using expensive polymers such as special silica, silicone rubber, and silicone-modified ethylene-propylene rubber with a large specific surface area. Even if it is below, since it is possible to obtain a bridge rubber bearing body that exhibits the equivalent rigidity required for the bridge rubber bearing body, an increase in cost can be suppressed.

  Hereinafter, a rubber bearing body for a bridge according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a rubber bearing body according to the present embodiment. The rubber support 11 is a structure formed by alternately laminating and bonding rigid hard plates 12 and viscoelastic rubber layers 13.

  The hard plate 12 includes an internal hard plate 12a disposed inside the rubber bearing 11, an upper hard plate 12b disposed at the upper portion, and a lower hard plate 12c disposed at the lower portion. As these hard boards 12, materials, such as metal plates, such as a steel plate, ceramics, a hard plastic board, can be used, for example. The internal hard plate 12a is preferably about 1 to 6 mm in thickness, and is preferably about 3 to 10 sheets. The upper hard plate 12b and the lower hard plate 12c may have a thickness of about 20 to 60 mm.

  The rubber support 11 has an attenuation constant (heq) in the range of 0.04 ≦ heq ≦ 0.1, preferably 0.04 ≦ heq ≦ 0.08, in the range of the environmental temperature from −10 ° C. to 40 ° C., and the rate of change in equivalent stiffness (R). Is in the range of R ≦ 0.25, preferably R ≦ 0.23. Here, the rate of change (R) is a value obtained from R = | K (40 ° C.) − K (−10 ° C.) | / K (40 ° C.). K (40 ° C) indicates an equivalent stiffness value at 40 ° C, and K (-10 ° C) indicates an equivalent stiffness value at -10 ° C.

  The rubber layer 13 includes a vulcanizing agent, a vulcanization accelerator, a vulcanization acceleration aid, an anti-aging agent, a reinforcing agent, a retarder, a plasticizer, and a colorant as necessary, in the rubber component as a main component. It is a combination of agents. In particular, in the present invention, carbon black and silica are blended in the rubber layer 13 as a blending agent at a predetermined blending ratio. As for the rubber layer 13, it is good that the thickness of each layer is about 1-50 mm.

  Carbon black and silica have a ratio of {silica compounding amount [A] (mass) / carbon black compounding amount [B] (mass)} ≧ 0.15, preferably 0.15 ≦ ([A] / [B]) ≦ 0.45 Is added to the rubber layer 13. In particular, carbon black is blended at 50 parts by weight or less, preferably 30-50 parts by weight, and silica is blended at 4.5-20 parts by weight with respect to 100 parts by weight of the rubber component of the rubber layer 13. Is good. By blending carbon black and silica under such blending conditions, it is within the above range required for the rubber bearing body for bridges without deteriorating the damping characteristics, and the equivalent stiffness change rate is within the above range. The temperature dependency of rigidity can be reduced. On the other hand, if the blending amount of carbon black and silica is larger than the above range, the processability when producing the rubber support 11 may be lowered. Moreover, when these compounding quantities are less than the said range, there exists a possibility that the damping characteristic required as a rubber bearing body for bridges may fall, or the temperature dependence of equivalent rigidity may become large.

  As the rubber component, for example, a diene rubber can be used. Examples of the diene rubber include natural rubber and synthetic rubber such as chloroprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, butadiene rubber, isoprene rubber, butyl rubber, and halogenated butyl rubber.

  Examples of the vulcanizing agent include sulfur, organic peroxide, zinc white, and magnesia. Examples of the vulcanization acceleration aid include zinc white and stearic acid. Examples of the antioxidant include amine compounds such as phenyl-α-naphthylamine, N, N′-diphenyl-p-phenylenediamine, and N-phenyl-N′-isopropyl-p-phenylenediamine; 2,6-di- and phenolic compounds such as t-butyl-p-cresol and 4,4′-butylidenebis (3-methyl-6-t-butylphenol). Examples of the plasticizer include petroleum-based process oil, tar, pitch, natural fats and oils, animal and vegetable fats and oils, and synthetic plasticizers. Examples of the reinforcing agent include carbon black and silica as well as white carbon.

  In such a rubber support 11, for example, an internal hard plate 12a, an upper hard plate 12b, and a lower hard plate 12c are arranged at predetermined intervals in a mold, and various compounding agents are added to the rubber component in the mold. It can be produced by injecting a rubber composition blended with an injection or the like and bonding them together at the same time as vulcanization molding.

  As another method for manufacturing the rubber support 11, a rubber composition in which various compounding agents are blended with a rubber component is molded by extrusion molding or the like to produce a plurality of soft plates having a predetermined thickness. Examples include a method of laminating a soft plate, an internal hard plate 12a, an upper hard plate 12b, and a lower hard plate 12c and bonding them with an adhesive or the like. Examples of the adhesive include thermoplastic adhesives such as vinyl acetate, acrylic, ethylene copolymer, dope cement, monomer cement, polyamide, polyester, and polyurethane; chloroprene rubber, nitrile rubber, recycled rubber, styrene- Examples thereof include rubber adhesives such as butadiene rubber (SBR) and natural rubber.

  As described above, the embodiment of the present invention has been described. However, in the rubber bearing body for a bridge according to the present invention, the shape, the number of laminated hard plates, the number of laminated rubber layers, and the like may be appropriately set according to the use situation. The invention is not limited to the above embodiment.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited to a following example.

[Examples 1 to 3 and Comparative Examples 1 and 2]
A rubber composition was prepared by blending each compounding agent at a compounding ratio shown in Table 1 with respect to 100 parts by mass of the rubber component (natural rubber (NR)). Next, an internal hard plate (5 sheets), an upper hard plate (1 sheet), and a lower hard plate (1 sheet) are arranged at predetermined intervals in the mold of the molding machine, and the rubber composition is placed in the mold. The rubber supports as shown in FIG. 1 were obtained by injecting and vulcanizing and integrating them at the same time. Details of the obtained rubber bearing are shown below.
Rubber bearing size: Length 420mm, width 420mm, height 134mm
Size of internal hard plate: length 400mm, width 400mm, thickness 3.2mm
Size of upper and lower hard plates: length 400mm, width 400mm, thickness 32mm
Rubber layer: Thickness 9 mm × 6 layers Width W1 in FIG. 1: 10 mm
(Width W1: Dimension from the end of the upper / lower hard plate to the side of the rubber bearing)
Material of internal hard plate: SS400 (JIS G3101)
Material of upper and lower hard plates: SM490 (JIS G3106)

<Equivalent stiffness, damping constant>
The equivalent stiffness and damping constant of each rubber bearing obtained as described above were measured as follows.
That is, the equivalent stiffness when the test temperature is −10 ° C. under the action of a vertical load of 6 N / mm ² , and a horizontal force having a shear strain amplitude of ± 175% and a frequency of 0.5 Hz is repeatedly applied to the rubber bearing body 11 times. The value K (−10 ° C.) and the damping constant heq (−10 ° C.) were obtained by the following equations (I) and (II), respectively.
In addition, the equivalent stiffness value K (40 ° C.) and the damping constant heq (40 ° C.) were determined by the following equations (I) and (II) in the same manner as described above except that the test temperature was 40 ° C.

<Change rate of equivalent stiffness>
The change rate (R) of the equivalent stiffness was obtained by substituting the equivalent stiffness K (-10 ° C) and K (40 ° C) obtained from the above into the following formula (III). The results are shown in Table 1.

Next, using each rubber composition blended at a blending ratio shown in Table 1, a test body 21 as shown in FIG. 2 was produced. The test body 21 includes an upper hard plate 22b, an internal hard plate 22a and a lower hard plate 22c, and a rubber layer 23 laminated and bonded therebetween. Details of the test body 21 are shown below.
Internal hard plate size: Length 101mm, width 25mm, thickness 10mm
Size of upper and lower hard plates: length 110mm, width 25mm, thickness 10mm
Rubber layer: length 25mm, width (W2) 25mm, thickness (t) 5.1mm
Hard plate material: SS400 (JIS G3101)

The equivalent stiffness values K (−10 ° C.), K (40 ° C.) and damping constants heq (−10 ° C.) and heq (40 ° C.) of the manufactured test body 21 are expressed by the above formula (I), Obtained by (II). Further, these values were substituted into the formula (III) to obtain the rate of change (R) of the equivalent stiffness. The results are shown in Table 1.

  From Table 1, it can be seen that the rubber bearing body of Comparative Example 2 containing no silica does not have the damping characteristics required for the rubber bearing body for bridges. Further, in Comparative Example 1 in which the mixing ratio [A] / [B] of silica and carbon black is less than 0.15, the change rate of the equivalent stiffness is large and the temperature dependency is large. On the other hand, Examples 1 to 3, in which the compounding ratio [A] / [B] of silica and carbon black is 0.15 or more, have the damping characteristics required for the rubber bearing body for bridges, and also change in equivalent rigidity. The rate is small and the temperature dependency is small.

It is sectional drawing which shows the rubber bearing body concerning one Embodiment of this invention. It is sectional drawing which shows the test body used for evaluation in an Example.

Explanation of symbols

11 Rubber bearing body 12 Hard plate 12a Internal hard plate 12b Upper hard plate 12c Lower hard plate 13 Rubber layer

Claims (3)

It is a rubber bearing in which rigid hard plates and rubber layers are alternately laminated, and in the range of environmental temperature from -10 ° C to 40 ° C, the damping constant (heq) is in the range of 0.04 ≦ heq ≦ 0.1, A rubber bearing for a bridge characterized in that the rate of change (R) in equivalent stiffness represented by the following formula is in a range of R ≦ 0.25.

  2. The rubber support for a bridge according to claim 1, wherein carbon black and silica are blended in the rubber layer in a ratio of {silica blending amount (mass) / carbon black blending amount (mass)} ≧ 0.15. The rubber support for a bridge according to claim 2, wherein the carbon black is blended at a ratio of 50 parts by mass or less with respect to 100 parts by mass of the rubber component of the rubber layer.

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