JP2020122356A - Method for replacing bridge bearing - Google Patents

Abstract

To provide a method for replacing bridge bearing capable of safely performing work even when a superstructure is lifted to replace a plurality of consecutively arranged bearings at once.SOLUTION: A method of replacing bearings 10 that constitute a bridge by lifting a bridge superstructure 102 having girders spanning a plurality of bridge piers 100 with a hydraulic jack 14 in which: a displacement restricting bracket 18 is extended vertically downward from the lower surface of a main structure located at the bottom of the bridge with the installation position of the bearings 10 as a base point; the superstructure 102 is lifted and lowered by the hydraulic jack 14 while restricting the change in the distance between the displacement restricting bracket 18 and the bridge pier 100 on which the bearings 10 are arranged via a hydraulic jack 22; and the replacement work for multiple bearings 10 is performed in a single lifting operation.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to seismic reinforcement of a bridge, and particularly relates to a construction method suitable for replacing a bearing in the bridge.

In response to the collapse of bridges caused by the earthquake, in recent years, as a part of seismic reinforcement of existing bridges, work such as adding functions to bearings and replacing bearings themselves has been underway. For example, the technique disclosed in Patent Document 1 discloses that a function-separated sliding bearing is added while leaving the existing bearing. That is, in Patent Document 1, a pedestal for installing a newly added sliding bearing is installed on the side surface of a skeleton body such as a pier, and the sliding bearing is arranged between this pedestal and the lower chord member or stringer.

Further, Patent Document 2 discloses that an existing bearing is replaced with one having a seismic isolation function. Specifically, a reinforcing member is arranged between the end column and the lower chord member forming the truss bridge, and a jack receiver is provided on this reinforcing member. Then, a hydraulic jack is installed between the upper surface of the pier and the lower surface of the jack receiver (jack receiving surface), and the superstructure is lifted to replace the bearing.

JP, 2008-38504, A JP, 2009-19438, A

Since the construction method disclosed in Patent Document 1 requires the existing bearings to be used for the work, it is considered that large-scale work such as lifting of a superstructure by a jack is unnecessary, and construction costs can be suppressed. To be However, since the existing bearing suppresses the transmission of force in the sliding direction, the function of the function-separated type sliding bearing is hindered, and there is a possibility that a sufficient seismic isolation effect cannot be obtained.

Further, the technique disclosed in Patent Document 2 is based on the premise that the bearings that are supported at the two end portions are replaced one by one, and this construction method is applied to the bearings of bridge girders that span multiple piers. In that case, a very long construction period is required and the cost is increased. However, if an attempt was made to lift the superstructure including bridge girders that span multiple bridge piers over a wide area and replace multiple bearings at once, the superstructure would be displaced in the bridge axis direction, causing a major accident such as disengagement of the bearings. May lead to.

Therefore, an object of the present invention is to provide a bridge bearing replacement construction method capable of safely performing work even when a plurality of bearings continuously arranged are lifted by lifting a superstructure.

The bridge bearing replacement method according to the present invention for achieving the above object is a method for replacing the bearing by lifting the bridge superstructure having girders bridged over a plurality of bridge piers with the first jack. Then, the displacement limiting bracket is extended vertically downward from the lower surface of the main structure located at the lower part of the bridge with the installation position of the bearing as a base point, and the displacement limiting bracket is provided via the second jack, Performing lifting and lowering of a superstructure by the first jack in a state in which a change in the distance from the bridge pier in which the bearing is arranged is suppressed, and performing replacement work of a plurality of the bearings in one lifting and lowering work. Is characterized by.

In addition, as a bridge bearing replacement construction method according to the present invention for achieving the above object, the bridge replacement work having a girder suspended over a plurality of bridge piers is lifted by the first jack to replace the bearing. A construction method to perform, in which the displacement limiting bracket is extended vertically downward from the lower surface of the main structure located at the lower part of the bridge with the installation position of the bearing as a base point, and on the pier side where the bearing is arranged. A pressing bracket having a surface facing the displacement limiting bracket is disposed, a jack receiver is provided between the displacement limiting bracket and the pressing bracket, and a second bracket is provided so as to extend along the bridge axial direction with respect to the jack receiver. The upper work is moved up and down by the first jack while the jack is arranged and the change in the distance between the displacement limiting bracket and the pressing bracket is suppressed, and the replacement work of the plurality of bearings is performed once. It can be characterized in that it is performed in.

Further, in the bridge bearing replacement construction method having the above characteristics, the first jack and the displacement limiting bracket, the pressing bracket, the jack receiver, and the second jack are arranged at the positions where the bearings are arranged. It is advisable that they are arranged in pairs at positions opposite to each other in the bridge axis direction with respect to the base point. With such characteristics, it is possible to prevent the superstructure from moving in the bridge axis direction regardless of the direction in which the force acts.

Further, in the bridge bearing replacement method having the above-mentioned features, the jack receiver can be arranged so as to extend toward the pressing bracket side with the displacement limiting bracket as a base point. By arranging the jack receiver on the displacement limiting bracket, the jack also moves when the superstructure is lifted. Therefore, the application of tension by the second jack can be stabilized.

Further, according to the bridge bearing replacement construction method of the present invention for achieving the above object, it is possible to safely perform work even when a plurality of bearings arranged continuously are replaced at a time. In addition, the construction period can be shortened compared to the case where bearings are individually replaced for each pier.

It is a partial enlarged view for explaining the composition for enforcing the bearing replacement construction method of the bridge concerning an embodiment. It is a perspective view which shows an example of the form of the jack receptacle in embodiment. FIG. 3 is a partially enlarged view showing the arrangement relationship between the temporary receiving bracket, the displacement limiting bracket, the pressing bracket, the jack receiver, and the hydraulic jack in the embodiment. It is a figure which shows the AA cross section in FIG. It is a figure which shows the BB cross section in FIG. It is a figure which shows the structure of the bridge used as the object of bearing replacement by this invention. It is a flow for explaining the procedure for implementing the bridge bearing replacement construction method according to the present invention.

Hereinafter, embodiments of the bridge bearing replacement method of the present invention will be described in detail with reference to the drawings. In the drawings, FIG. 1 is a partially enlarged view for explaining a configuration for carrying out a bridge bearing replacement method according to an embodiment. FIG. 2 is a perspective view showing an example of the form of the jack receiver in the embodiment. FIG. 3 is a partially enlarged view showing the positional relationship between the temporary receiving bracket, the displacement limiting bracket, the pressing bracket, the jack receiver, and the hydraulic jack in the embodiment. 4 is a diagram showing a cross section taken along the line AA in FIG. 3, and FIG. 5 is a diagram showing a cross section taken along the line BB in FIG. Further, FIG. 6 is a schematic diagram showing the configuration of a bridge to which the bearing replacement method according to the present embodiment is applied.

[Constitution]
In the present embodiment, as shown in FIG. 6, a bridge replacement in which a plurality of bridge piers that are continuously arranged are hung on a girder is targeted, and the entire superstructure 102 of the bridge supported by the plurality of supports 10 is lifted. , Is intended to replace multiple bearings 10 at once.

As shown in FIG. 1, the work of replacing the bearings of the bridge is generally performed by installing a temporary bracket 12 on the side surface of the pier 100 on which the bearings 10 are arranged and then using a hydraulic jack 14 (first jack). The superstructure 102 (see FIG. 6) on the bridge is lifted. Note that FIG. 1 shows a part of the structure of the truss bridge as an example of the specific structure of the bridge. The height adjustment block 16 is arranged on the upper surface of the temporary support bracket 12 and the upper surface of the bridge pier 100, and the lower chord member 104 or the longitudinal girder (on which the lower chord member 104 is given as an example in the following description will be described. The hydraulic jack 14 is arranged after adjusting the clearance between the hydraulic jack 14 and Here, the temporary receiving bracket 12 plays a role of preventing the supporting portion of the pier 100 from falling off due to the load applied to the hydraulic jack 14.

The hydraulic jack 14 has a position on the opposite side in the bridge axial direction from the position where the support 10 is arranged as a base point (while the distance from the support 10 is equal, the arrangement height is such that the gap between the pier 100 and the lower chord member 104 is large). Are arranged in a pair. This is to balance the weight when the superstructure 102 is lifted.

In this embodiment, in addition to the above construction requirements, construction is performed by adding the following configuration. That is, in the lower chord member 104 on which the support 10 is arranged, the displacement limiting bracket 18 extending in the vertically downward direction is provided on the lower surface side at a position spaced from the bridge pier 100 in the bridge axial direction. .. The arrangement of the displacement limiting bracket 18 is not particularly limited, and may be welding or bolting, for example. Further, although the configuration of the displacement limiting bracket is not limited, it can be made of, for example, H-section steel in which the web 18b is arranged between the pair of flanges 18a.

A jack receiver 20 is provided on the lower end side of the displacement limiting bracket 18. The jack receiver 20 is an element for arranging the hydraulic jack 22 (second jack). For example, as shown in the perspective view of FIG. 2, a web 20c is arranged between the upper flange 20a and the lower flange 20b. A steel plate 20d may be provided on one end of the shape steel, and the steel plate 20d may be coupled to the flange 18a of the displacement limiting bracket 18 via the steel plate 20d. The jack receiver 20 is provided with a guide 24 made of L-shaped steel. The guides 24 are preferably arranged so as to sandwich the lower flange 20b of the H-shaped steel forming the jack receiver 20 so that the L-shaped plane faces the web 20c.

By arranging and fixing the L-shaped steel in this way, a cross groove is formed at the center of the guide 24 constituted by the L-shaped steel (see FIG. 2). By inserting the web 12a of the temporary receiving bracket 12 into the vertical groove of the cross groove formed in the guide 24, when the superstructure 102 is lifted, it is possible to suppress the displacement in the direction intersecting the bridge axis direction. ..

A pressing bracket 26 is provided on the pier 100 side so as to follow the web 12a of the temporary receiving bracket 12. As shown in FIG. 3, the pressing bracket 26 is provided with a jack receiving surface 26 a facing the displacement limiting bracket 18, and is configured to transmit the pressing force of the hydraulic jack 22 arranged on the jack receiver 20 to the pier 100.

The hydraulic jack 22 is arranged on the jack receiver 20 such that the extension direction is along the bridge axis direction. Therefore, the hydraulic jack 22 causes a force in the tension direction between the displacement limiting bracket 18 and the pressing bracket 26.

The displacement limiting bracket 18 having such an arrangement configuration, the pressing bracket 26, the jack receiver 20, the guide 24, and the hydraulic jack 22 are on opposite sides in the bridge axis direction with the bearing 10 as a base point (substantially line-symmetrical). By arranging the upper jack 102 and the upper jack 102 so as to form a pair, the movement of the superstructure 102 in the bridge axial direction can be suppressed when the tension force is applied to the hydraulic jack 22. That is, even when a force in the bridge axis direction is applied when the superstructure 102 is lifted over a wide range, it is possible to suppress the change in the distance between the displacement limiting bracket 18 and the pressing bracket 26. Therefore, it is possible to prevent a major accident in which the superstructure 102 falls off from the hydraulic jack 14.

Further, when the seismic isolation bearing 50 is installed, even if the position of the superstructure 102 is adjusted in the bridge axis direction, the position of the superstructure 102 can be finely adjusted by operating the hydraulic jack 22. ..

In the above embodiment, the arrangement of the hydraulic jack 22 is illustrated such that the cylinder is arranged on the displacement limiting bracket 18 side and the rod is arranged on the pressing bracket 26 side, but the arrangement direction of the hydraulic jack 22 is reversed. Even if they are arranged in the direction, the same effect can be obtained, and it does not affect the implementation of the present invention.

[Construction method]
Next, with reference to FIG. 7, an implementation procedure of the bridge bearing replacement method according to the present invention will be described. In the bridge bearing replacement construction method according to the present invention, after arranging the respective elements as described above (step 10), the hydraulic jack 22 is operated so that the pressure bracket 26 and the displacement limiting bracket 18 are provided between them. The tension force is generated to suppress the change in the distance between the two (step 20).

Next, the hydraulic jack 14 is operated and the superstructure 102 is raised to cause a slight gap between the bearing 10 and the lower chord member 104. Here, it goes without saying that the fastening state between the bearing 10 and the lower chord member 104 is released before raising the superstructure 102 (step 30).

After raising the superstructure 102 through the hydraulic jack 14, the bearing 10 is removed and the seismic isolation bearing 50 is arranged (step 40). After the seismic isolation bearing 50 is arranged, the superstructure 102 is lowered via the hydraulic jack 22 to switch to the support by the seismic isolation bearing 50 (step 50). After the superstructure 102 is supported by the seismic isolation bearing 50, the tension by the hydraulic jack 22 is released (step 60).

[effect]
According to the bridge bearing replacement method that goes through such a process, it is possible to safely perform the work even when the superstructure 102 is lifted to replace a plurality of continuously arranged bearings 10 at once. .. Further, since it is not necessary to repeatedly raise and lower the superstructure 102 at each location where the bearing 10 is replaced, the construction period can be shortened. Furthermore, due to the shortened construction period, the construction cost can be reduced.

In the above-described embodiment, as a specific example for carrying out the invention, the form of each component is illustrated, and the configuration thereof is described as necessary. However, in implementing the bridge bearing replacement method according to the present invention, the specific configuration is not limited as long as it is an element capable of exhibiting the same effect.

10... Support, 12... Temporary bracket, 12a... Web, 14... Hydraulic jack, 16... Adjustment block, 18... Displacement limiting bracket, 18a... Flange, 18b... ......Web, 20 …………Jack receiver, 20 a …………Upper flange, 20 b …………Lower flange, 20 c …………Web, 20 d …………Steel plate, 22 …………Hydraulic jack, 24 …………Guide, 26...Pressing bracket, 26a...jack receiving surface, 50...Seismic isolation support, 100...pier, 102...superstructure, 104...lower chord.

Claims (4)

A method of replacing the bearing by lifting the bridge superstructure with girders spanning multiple bridge piers using the first jack.
Extending the displacement limiting bracket from the lower surface of the main structure located at the bottom of the bridge with the installation position of the bearing as a base point in the vertically downward direction,
In a state in which a change in the distance between the displacement limiting bracket and the pier on which the bearing is arranged is suppressed via the second jack,
Lifting and lowering the superstructure by the first jack,
A bridge bearing replacement method, characterized in that a plurality of bearing replacement works are performed in one lifting operation. A method of replacing the bearing by lifting the bridge superstructure with girders spanning multiple bridge piers using the first jack.
The displacement limiting bracket is extended vertically downward from the lower surface of the main structure located at the lower part of the bridge with the installation position of the bearing as a base, and the displacement limiting bracket is attached to the pier side where the bearing is arranged. Place the pressure bracket with the opposing surface,
A jack receiver is provided between the displacement limiting bracket and the pressing bracket,
A second jack is arranged along the bridge axial direction with respect to the jack receiver, and a change in the distance between the displacement limiting bracket and the pressing bracket is suppressed,
Lifting and lowering the superstructure by the first jack,
A bridge bearing replacement method, characterized in that a plurality of bearing replacement works are performed in one lifting operation. The first jack, the displacement limiting bracket, the pressing bracket, the jack receiver, and the second jack are paired at positions opposite to each other in the bridge axial direction with the arrangement position of the bearing as a base point. 3. The bridge bearing replacement construction method according to claim 2, wherein the bridge bearing replacement construction method is carried out. The bridge support replacement method according to claim 2 or 3, wherein the jack receiver is extended toward the pressing bracket with the displacement limiting bracket as a base point.

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