JPH09100511A - Rubber bearing body and bearing structure of bridge using this bearing body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce internal stress of a rubber bearing body and secure an intrinsic strength of a pier by using a material capable of relaxing the internal stress which is produced by the displacement in the shearing direction by the dry shrinkage of a concrete material as a rubber material. SOLUTION: A rubber bearing body device 1 is provided with an upper shoe 2 mounted on the bottom of concrete-made bride girder and a lower shoe 3 mounted on the top of a pier while a rubber bearing body 4 is fixed with the upper shoe 2. The rubber bearing body 4, which is substantially a rectangular-parallelepiped in shape, is slantingly formed in the vertical direction. The inclination direction is opposite to the shrinkage direction of the concrete material produced by its dry shrinkage. The inclination angle is displaced by about 7% of the thickness of the rubber bearing body 4 as for the shape of the rectangular parallelepiped. When the upper shoe 2 is moved by a specified distance, it is changed from the inclined state of the rubber bearing body 4 to a vertical state. While 24 hours have elapsed at an ambient temperature after the change, the stress relaxation rate of the rubber bearing body 4 drops to 40% and below. It, is, therefore, possible to reduce the reaction force imposed to the pier dramatically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reaction force dispersion type rubber support and a bridge support structure using the same.

[0002]

2. Description of the Related Art In recent years, bridge technology has been remarkably advanced, and the scale of bridges has been increasing year by year. Accordingly, many long bridges have been designed. As a bearing system for such a long bridge, conventionally, as shown in FIG. 15, a long span bridge girder 51 is used, and a rubber bearing 53 fixed to a large number of piers 52.
Fixed support. Such a bridge of the support system is called a bridge of a distributed reaction force (horizontal force), and effectively utilizes the horizontal rigidity of the rubber bearing to arbitrarily distribute the inertial force of the bridge girder 51 to each pier 52. The pier 52
The cross-sectional shapes of the bridges have been made uniform to improve the balance of the entire bridge.

[0003]

However, in the case of a concrete long bridge, since the length of the bridge girder 51 is 300 m, the bridge girder 51 dries during the second half to 1-2 years after construction. The contraction contracts about 10 cm in the longitudinal direction (see arrow A in FIG. 15). Therefore, as shown in FIG.
The rubber bearing 53 is distorted in the longitudinal direction of the bridge girder 51 (toward the center of the bridge girder 51). As a result, a reaction force is applied to the pier 52 due to the deformation of the rubber bearing 53, and the bridge girder 51
After the drying and shrinkage of the bridge, the bridge always receives a load in the longitudinal direction, which is disadvantageous in the strength of the pier 52. Therefore, as a means for removing the distortion of the rubber support after the bridge girder 51 has been dried and contracted, Japanese Patent Application Laid-Open No. 5-171 has been proposed.
A preliminary shearing deformation installation method disclosed in Japanese Patent No. 623 has been proposed. This method is as follows. That is, as shown in FIGS. 17 and 18, a bed plate 55 in which stoppers 56 are erected on both sides along the longitudinal direction of the bridge girder 51 and the like, and metal plates 59 and 60 are fixed to the upper and lower surfaces of the rubber layer 58. A rubber support 57 having a substantially rectangular parallelepiped shape is prepared, and the rubber support 57 is positioned and fixed to the center of the bed plate 55 with bolts 61a and 61b. Next, the bridge pier 52 or the like is constructed, and the bed plate 55 is fixed to the upper portion of the bridge pier 52 or the like. Next, the metal plate 5 of the rubber bearing 57
9 The locking projection 59a on the upper surface is fitted into the locking hole 62a on the lower surface of the sole plate 62, and the bridge girder 51 and the like are constructed in this state. Next, after removing the bolts 61a in the direction of dry shrinkage and creep of the bridge girder 51 and the like, the bolts 61b on the opposite side are tightened and rotated, and the lower metal plate 60 of the rubber support 57 is attached to the bridge girders 51 and the like. Presses and moves in the drying shrinkage and creep progress direction. In this way, the rubber layer 58 of the rubber support 57 is pre-shear-deformed, and then the bolt 6
1b is removed, a spacer is arranged in the gap formed between the stopper 56 and the lower metal plate 60, and bolted.

However, in this case, the bolt 61
Since it is very difficult to set the distance for tightening and rotating b to press and move the lower metal plate 60 of the rubber bearing 57, the accurate distance cannot be set, and the rubber bearing 57 does not dry even after the bridge girder 51 or the like shrinks. There is a problem in that the shearing deformation continues to act on the rubber layer 58 and the rubber bearing 57 is damaged early. Moreover, in this structure, shear deformation acts on the rubber layer 58 of the rubber support 57 from the initial state, and the bolt 61
Since the shearing deformation is rapidly given by the tightening of b, there is a problem that the rubber layer 58 is likely to be cracked. further,
Since it is necessary to perform fine manual work such as tightening work of the bolt 61b and mounting work of the spacer in a narrow place, the work is troublesome.

The present invention has been made in view of such circumstances, and reduces the internal stress of the rubber bearing to reduce the internal stress of the bridge pier without the need for construction work for readjustment of the bridge girder after drying and shrinking. It is an object of the present invention to provide a rubber support body capable of ensuring strength and a bridge support structure using the same.

[0006]

In order to achieve the above object, the present invention provides a rubber bearing for fixing a bridge girder made of concrete, which is fixed on a pier and is fixed on itself.
As the rubber material, when the bridge girder is displaced in its longitudinal direction due to the dry shrinkage of the concrete material that constitutes the bridge girder,
A rubber bearing which uses a rubber material capable of relaxing internal stress generated by itself displacing in the shearing direction due to this displacement is defined as a first gist, and a bridge bearing structure using the rubber bearing is described. Is the second gist.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION That is, the rubber bearing of the present invention, as its rubber material, when the bridge girder is displaced in its longitudinal direction due to the drying shrinkage of the concrete material constituting the bridge girder, the rubber bearing itself is accompanied by this displacement. A rubber material is used that can relieve the internal stress caused by displacement in the shear direction. Therefore, when the bridge girder is displaced in the longitudinal direction due to the dry shrinkage of the concrete material that is its constituent material, the rubber bearing is displaced in the shearing direction due to this displacement, but the rubber material is made of a material with a large stress relaxation. Therefore, the creep of the rubber is generated, the internal stress of the rubber bearing is relaxed, and the residual stress can be reduced or removed. Therefore, the reaction force applied to the pier becomes significantly small when the bridge girder is dried and contracted. Further, in the present invention, the selection of the rubber material is not so difficult as the setting of the pressing movement distance in the conventional example, and the internal stress of the rubber bearing can be reduced or eliminated by selecting the proper rubber material. . Moreover, in this product, displacement in the shearing direction acting on the rubber bearing gradually occurs during the period such as drying shrinkage of the concrete material, and this internal stress is small due to the properties of the rubber material of the rubber bearing, or Since it can be removed, the rubber bearing will not be cracked during work. Further, since the fixing work of the rubber bearing does not require the finer work as the tightening work and the attaching work as in the conventional example, it can be easily performed even in a narrow place. On the other hand, by adopting a bridge support structure using such a rubber support, it is possible to obtain a support structure that is excellent in durability and has the above-mentioned excellent operational effects.

Further, in the present invention, when a displacement amount of 70% of the thickness of the rubber layer is applied in the longitudinal direction of the bridge girder, it is 2 at room temperature.
When the stress relaxation rate after 4 hours is 40% or more, sufficient stress relaxation can be obtained against the normal displacement amount (70% of the thickness of the rubber layer) due to drying shrinkage and temperature change of the concrete material. (See FIGS. 10 and 11). In FIG. 11, the rubber bearing is composed of only a rubber layer. In the present invention, the stress relaxation rate is calculated from the internal stress (P ₀ ) of the rubber bearing when the bridge girder is displaced in the longitudinal direction due to the dry shrinkage of the concrete material, and the internal stress (P ₁ ) after the stress relaxation. It is a calculated value and is represented by the following equation (1).

[0009]

## EQU1 ## Stress relaxation rate = (P ₀ −P ₁ ) / P ₀ × 100 (%) ... (1)

Further, in the present invention, the longitudinal side surface of the bridge girder is formed so as to be inclined at a predetermined angle with respect to the vertical direction,
In that state, when the bridge girder is dry and shrinks, the side surface becomes a substantially vertical surface, and when the bridge girder is dry and shrinks, the pressure receiving area of the rubber part increases substantially (in the initial fixed state, In L of FIG. 8 showing the length of the effective pressure receiving area and L ′ of FIG. 9 showing it after the drying shrinkage, L ′ is longer than L, whereby the effective pressure receiving area increases after the drying shrinkage. Therefore, the compressive stress due to the load during actual use decreases. Further, when at least one intermediate plate is embedded inside, the rubber bearings are divided into a plurality of rubber plates by the intermediate plates, so that the compression platen of each rubber plate is reduced.

Next, the present invention will be described in detail.

The rubber bearing of the present invention, as its rubber material, when the bridge girder is displaced in its longitudinal direction due to the drying shrinkage of the concrete material constituting the bridge girder, the rubber bearing itself is displaced in the shearing direction with this displacement. A rubber material that can relieve the internal stress caused by this is used.

Examples of the rubber material include chlorinated butyl rubber, chloropyrene rubber (CR), a mixture of natural rubber (NR) and butadienestyrene rubber (SRB), and the like. Chlorinated butyl rubber is preferably used. . When such a rubber material is used, the stress relaxation rate after 24 hours at room temperature when the displacement amount of 70% of the thickness of the rubber layer is applied in the longitudinal direction of the bridge girder can be set to 40% or more.

The rubber support may be formed of one kind of rubber alone, or may be formed in a multi-layer structure in which the rubber plates and the intermediate plates are alternately laminated by embedding the intermediate plates inside. Good. In the case of this multilayer structure, each rubber plate may be formed of the same rubber material, or may be formed of different rubber materials.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of a rubber bearing device 1 according to the present invention. The bearing device 1 includes an upper shoe 2 attached to the lower surface of a concrete bridge girder and a lower shoe 3 attached to the upper surface of a bridge pier. The upper shoe 2 has the rubber bearing of the present invention. The body 4 is fixed. FIG. 2 is a view looking up from below. As shown in FIG. 3, the upper shoe 2 is a main body 5 composed of a rectangular flat plate made of iron.
And four anchor bolts 6 (two of which are hidden and invisible) which are erected on the upper surface of the main body 5.

The rubber bearing 4 is, as shown in FIG.
It is formed by inclining a substantially rectangular parallelepiped with respect to the vertical direction (this inclination direction is opposite to the direction in which the bridge girder contracts due to the drying shrinkage of the concrete material constituting it (the direction of the arrow in the figure)). Direction, and the inclination angle is set to an angle calculated in advance. For example, it is preferable to displace about 70% of the thickness of the rubber bearing 4 with respect to the rectangular parallelepiped shape), this rubber bearing A rectangular plate-shaped iron upper fixing plate 8 is fixed to the upper surface of 4 by bonding or the like, and a rectangular plate-shaped iron lower fixing plate 9 is fixed to the lower surface by bonding or the like.
On the lower surface of the lower fixing plate 9, a fixing plate (convex) 10 formed of an iron square plate is provided by welding or the like. As shown in FIGS. 5 and 6, the rubber bearing 4 has a side surface 4c (in the drawings, which is orthogonal to the contracting direction of the bridge girder (that is, the longitudinal direction of the bridge girder, indicated by an arrow in the drawing)).
The left and right side surfaces are inclined as shown in the drawing, so that the upper surface is displaced from the lower surface in the direction opposite to the contraction direction (the direction opposite to the arrow in the figure).
A rectangular rubber plate 4a made of chlorinated butyl rubber and 5
It is configured by alternately laminating and adhering a rectangular flat plate 4b made of stainless steel (four left and right and front and rear side surfaces are formed as vertical surfaces). Such a rubber bearing 4 is
As shown in FIG. 2, by screwing the upper plate 8 to the lower end surface of the upper shoe 2 with eight mounting bolts 11,
It is integrally fixed to the upper shoe 2.

The lower shoe 3 is composed of a main body 12 made of a flat plate made of iron and four anchor bolts 13 (two of which are hidden and invisible) which are provided upright on the lower surface of the main body 12 ( (See FIG. 1). As shown in FIG. 7, the main body 12 is formed in a square shape, and a square recess 14 that fits into the fixing plate 10 of the rubber support 4 is formed in the central portion thereof. In the figure, reference numeral 15 is a guide plate formed at four corners of the upper surface of the main body 12 to guide the lower fixed plate 9 in the left-right direction.

In the above construction, the upper and lower gears 2 and 3 are positioned so that the fixing plate 10 of the rubber bearing 4 attached to the upper gear 2 is located right above the recess 14 of the lower gear 3. When the upper shoe 2 is lowered and placed on the lower shoe 3, the fixing plate 10 of the upper shoe 2 is fitted into the concave portion 14 of the lower shoe 3 automatically as shown in FIG. Positioned and fixed to. From this state, due to the dry shrinkage of the concrete of the bridge girder attached to the upper shoe 2, when the upper shoe 2 moves a predetermined distance in the right direction (arrow direction) in FIG. 8, the rubber bearing 4 shifts from the inclined state to the vertical state. If the above deviation disappears,
A slight amount remains (see FIG. 9). The internal stress generated in each rubber plate 4a of the rubber support 4 during a predetermined time (for example, 24 hours) at room temperature after the above transition is relaxed by the property of each rubber plate 4a. The stress relaxation rate drops to 40% or more (see FIGS. 10 and 11).

When a bridge is produced by using such a supporter device 1, for example, the fixing plate 10 of the upper shoe 2 is fitted into the recess 14 of the lower shoe 3 in advance, and the upper shoe 2 is lowered. Place it on the top and temporarily fix it with a temporary fixing tool such as a string or wire in that state,
Bring it to the work site. After this loading, the lower shoe 3 fixed temporarily by the above-mentioned temporary fixture is temporarily installed by a temporary means such as a plate material in the lower shoe fixing portion 21 formed by being surrounded by a frame material or the like on the upper portion of the pier formed in advance. (See Figure 12). Then
A concrete material is poured into the lower shoe fixing portion 21 to produce the lower shoe fixing portion 21. At the same time, the lower shoe fixing part 2
On the upper surface of 1, the lower shoe 3 and the bolt 13 are attached to the lower shoe fixing portion 21.
It is embedded and fixed in the concrete part of. Next, the upper shoe 2 is temporarily provided with a plate material or the like in a state of facing the lower shoe 3 to the upper shoe fixing portion 20 formed by being surrounded by the frame material or the like on the lower surface of the bridge girder formed in advance. Prior to this, the temporary fixing of the temporary fixing device is released, but the mutual positional relationship between the lower shoe 3 and the upper shoe 2 is maintained as it is (that is, the fixing plate 10 is fixed to the lower shoe 3). It remains fitted in the recess 14). Next, a concrete material is cast into the upper shoe fixing portion 20 to integrally produce the upper shoe fixing portion 20 on the bridge girder, and the upper shoe 2 is attached to the upper shoe fixing portion 20 by the bolt 6 thereof. It is embedded and fixed in 20 concrete parts. In this way, the bridge can be completed by sequentially attaching the bridge girders to the bridge piers. In the bridge manufactured in this way, the bridge girder moves toward the right direction (the direction of the arrow in FIG. 12) due to the drying shrinkage of the concrete material, etc., during a period of 1 or 2 years from the latter half of this construction. Along with this movement, the rubber bearing 4 shifts from the illustrated inclined state to the vertical state (see FIG. 13). When a predetermined time has elapsed after this transition, the rubber of the rubber support 4 creeps, the internal stress generated inside the rubber is reduced, and the reaction force to the pier can be reduced.

As described above, in the bearing device 1, the creep (permanent distortion) of the rubber plate 4a itself constituting the rubber bearing 4 is carried out.
Chlorinated butyl rubber (the chlorinated butyl rubber is a highly damping material, and this highly damping material generally has large creep) is selected as the rubber material for the rubber plate 4a. I'm using it. Therefore, even if the rubber bearing 4 is displaced in the shearing direction due to the drying shrinkage of the concrete material of the bridge girder and the internal stress is generated, the internal stress can be sufficiently removed. In this case, the selection of the rubber material and the work contents are simple, and it can be easily performed even in a narrow place. Moreover, in this structure, the displacement in the shearing direction acting on the rubber bearing 4 is gradually generated, and the internal stress caused thereby is gradually relaxed, so that the rubber bearing 4 may be cracked during this period. Absent.

In the above embodiment, the following rubber materials were used as the rubber material of the rubber plate 4a constituting the rubber support 4, and the stress relaxation rate in that case was measured. The results are shown in Table 1 (all of which were measured with a JIS A type hardness tester.
5-60HS).

[0023]

[Table 1]

FIG. 14 shows another embodiment of the present invention. In this embodiment, instead of attaching the fixing plate 10 to the lower fixing plate 9 of the rubber bearing 4, the recess 14 formed on the upper surface of the lower shoe 3 is made large enough to fit the lower fixing plate 9. The lower fixing plate 9 is formed in the recess 1
The rubber bearing 4 is fixed to the lower shoe 3 by fitting the rubber bearing 4 to the lower shoe 3. The other parts are the same as those in the above embodiment, and the same parts are denoted by the same reference numerals. This structure has a simpler structure than the above embodiment.

In each of the above embodiments, the rubber bearing 4 is fixed to the upper shoe 2 and the recess 14 is formed in the lower shoe 3. However, the present invention is not limited to this, and the recess is provided in the upper shoe 2. 14 may be formed, and the rubber bearing 4 may be fixed to the lower shoe 3.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a bearing device using a rubber bearing of the present invention.

FIG. 2 is a view of an upper shoe with a rubber bearing as viewed from below.

FIG. 3 is a side view of the upper shoe.

FIG. 4 is a side view of the rubber bearing.

FIG. 5 is a structural explanatory view of the rubber bearing.

FIG. 6 is a partially enlarged sectional view of the rubber bearing.

FIG. 7 is a plan view of the lower shoe.

FIG. 8 is a cross-sectional view of an essential part showing the operation of the bearing device.

FIG. 9 is a cross-sectional view of the main parts showing the operation of the above-mentioned support device.

FIG. 10 is a diagram showing the relationship between internal stress and displacement.

FIG. 11 is an explanatory diagram of a displacement amount.

FIG. 12 is an explanatory diagram of a main part of a bridge using the support device.

FIG. 13 is an explanatory view showing the operation of a bridge using the above-mentioned support device.

FIG. 14 is an explanatory diagram showing another embodiment of the present invention.

FIG. 15 is an explanatory diagram of a conventional example.

FIG. 16 is a diagram showing an operation of the conventional example.

FIG. 17 is an explanatory diagram of another conventional example.

FIG. 18 is an explanatory view showing the construction method.

[Explanation of symbols]

 1 Bearing device 2 Upper shoe 3 Lower shoe 4 Rubber bearing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sadaji Kumaoka 4 13 Arakicho Shinjuku-ku, Tokyo Sumitomo Construction Co., Ltd. (72) Inventor Shinichiro Kumagai 13 13 Arakicho Shinjuku-ku Tokyo Sumitomo Construction Co., Ltd. (72) Inventor Kazumichi Sasaki 4 13-Araki-cho, Shinjuku-ku, Tokyo Sumitomo Construction Co., Ltd.

Claims (5)

[Claims] 1. A rubber pedestal which is fixed on a pier and on which a concrete bridge girder is placed and fixed,
As the rubber material, when the bridge girder is displaced in its longitudinal direction due to the dry shrinkage of the concrete material that constitutes the bridge girder,
A rubber bearing characterized by using a rubber material capable of relaxing internal stress generated by itself displacing in the shearing direction due to this displacement. 2. 70% of the thickness of the rubber layer in the longitudinal direction of the bridge girder
The rubber bearing according to claim 1, wherein the stress relaxation rate after 24 hours at room temperature when the amount of displacement is given is 40% or more. 3. The side surface in the longitudinal direction of the bridge girder is formed so as to be inclined at a predetermined angle with respect to the vertical direction, and in that state, the initial fixed state is obtained, and the side surface becomes a substantially vertical surface after drying and shrinking of the bridge girder. The rubber bearing according to item 1. 4. The rubber bearing according to claim 1, wherein at least one intermediate plate is embedded inside. 5. A bridge support structure using the rubber support according to any one of claims 1 to 4.