JP7368685B2 - Bridge reconstruction method and bridge superstructure - Google Patents

Description

The present invention relates to a reconstruction method for removing an existing bridge and constructing a new bridge.

Generally, the lifespan of concrete is said to be 60 to 100 years. After more than half a century has passed since civil engineering structures made primarily of concrete or steel, it is often necessary to consider whether to make large-scale repairs to extend their lifespan, or to demolish the existing structures and construct new ones.

Regarding bridges, consideration is being given to replacing existing bridges by removing them and constructing new ones. However, construction conditions are often severe due to constraints imposed by the environment surrounding the bridge. In addition, rebuilding work tends to take a long time because it includes a removal process and a new installation process. Therefore, various rebuilding methods have been proposed depending on the construction conditions (for example, Patent Document 1).

For example, in the rebuilding method disclosed in Patent Document 1, first, an existing bridge girder installed on a bridge pier is supported from below by a jack installed on a transport vehicle. Cut both ends of the existing bridge girder to a length shorter than the pier span. Operate the jack to lower the existing bridge girder. The existing bridge girders are supported from below by jacks and then transported using a transport truck.

Meanwhile, a new bridge girder will be constructed on the remaining existing bridge girder adjacent to the new bridge girder replacement location. Furthermore, the new bridge girders will be hoisted up by a large crane and installed between the piers.

JP2003-034911A

Figure 12 is an example of an existing bridge. In urban areas, multiple railways run parallel to each other in narrow valleys, and bridges are sometimes built to span the valleys and intersect with the railroad tracks. Bridges built over half a century ago generally have short spans and are supported by piers in addition to abutments at both ends. Multiple railroads are passing between the piers or between the abutment piers.

When inspecting or maintaining bridges such as those mentioned above, it is necessary to take into account the railway operating conditions. In particular, inspection and maintenance of bridge piers sandwiched between railroad tracks requires extremely difficult work conditions. Therefore, it may be determined that rebuilding is more preferable. In recent years, spans have tended to become longer, making support by piers unnecessary. If the bridge structure is simplified, inspection and maintenance will be easier.

In the bridge reconstruction method described in Patent Document 1, a transport truck is placed on standby under a bridge. Under the construction conditions shown in FIG. 12, it is not preferable to have a transport vehicle waiting under the bridge, and it is difficult to apply the rebuilding method described in Patent Document 1. It is necessary to consider a reconstruction method suitable for the above construction conditions.

The present invention solves the above problems, and aims to provide a bridge reconstruction method that can be applied even when the construction conditions under the bridge are severe.

The present invention, which solves the above problems, is a bridge reconstruction method. A first connecting means extending in the bridge axis direction is provided on the lower surface side of the new bridge superstructure, and the new bridge superstructure is carried in using the upper surface of the existing bridge superstructure as a transportation path, and the existing bridge superstructure is Temporarily installing the new bridge superstructure on top of the superstructure, temporarily supporting both ends of the new bridge superstructure, connecting the first connecting means and the second connecting means, and connecting the first connecting means and the second connecting means via the second connecting means. the part of the existing bridge superstructure that corresponds to removal is suspended and supported by the new bridge superstructure, the part of the existing bridge superstructure that corresponds to removal is cut, the part of the existing bridge superstructure that corresponds to removal is lifted; by sliding the bridge via the first connecting means and removing it, repeating the removal of the portions of the existing bridge superstructure that correspond to the removal, removing the existing bridge superstructure, lowering the new bridge superstructure, and then removing the existing bridge superstructure. Set up

In the above procedure, there is no work under the bridge, and most of the work can be done using the top surface of the existing bridge superstructure. This makes it applicable even when construction conditions under bridges are severe.

In addition, the temporarily supported state of the newly constructed bridge superstructure can be used as temporary equipment for removing the existing bridge superstructure.

In addition, in this application, a superstructure includes a girder and a floor slab.

In the above invention, preferably, in removing the portion corresponding to removal of the existing bridge superstructure, the part is suspended onto the remaining part of the existing bridge superstructure, and the upper surface of the remaining part of the existing bridge superstructure is used as a transport path.

In this way, the remaining part of the existing bridge superstructure can be effectively utilized. In other words, work under the bridge can be eliminated.

Preferably, in the above invention, when removing the portion of the existing bridge superstructure that corresponds to removal, the removed portion is carried out in a sliding state to the outside of the existing bridge.

This allows the remaining part of the existing bridge superstructure to be effectively used as a work area.

In the above invention, preferably, the part of the existing bridge substructure corresponding to removal is suspended and supported by the new bridge superstructure via the second connecting means, the part of the existing bridge substructure corresponding to removal is cut, and the part of the existing bridge substructure corresponding to removal is suspended from the existing bridge substructure. Lift up the portion of the bridge substructure that corresponds to removal, further slide it through the first connecting means, remove it, repeat the removal of the portion of the existing bridge substructure that corresponds to removal, and remove the existing bridge substructure. do.

The proposed construction method can also be applied to the removal of existing bridge substructures. In addition, in this application, a lower structure includes a bridge pier and an abutment.

In the above invention, preferably, two or more of the second connecting means are provided in a direction perpendicular to the bridge axis, and the second connecting means are connected to each other via a hanging girder.

This makes it possible to adjust the hanging position and stabilize the hanging condition.

In the above invention, preferably, the state in which the first connection means is maintained is maintained even after the new bridge superstructure is permanently installed.

This makes it possible to reuse it during inspections after permanent installation.

Preferably, in the above invention, the existing bridge superstructure is provided on a railroad or road extending in a direction crossing the bridge axis.

The construction method of the present application is suitable when the construction conditions under such a bridge are severe. There is no work under the bridge, so it is not easily affected by the conditions under the bridge.

The present invention that solves the above problems is a bridge superstructure. A rail-shaped first connection means extending in the bridge axis direction is provided on the lower surface side of the newly constructed bridge superstructure.

That is, the first connecting means is a part of the newly constructed bridge and can be reused even after the bridge is permanently constructed.

The present invention that solves the above problems is a bridge superstructure. A rail-shaped first connecting means extending in the bridge axis direction is provided on the lower surface side, and the second connecting means is slidable along the first connecting means in a state where the second connecting means is connected to the first connecting means. It is possible to move.

The connection mechanism consisting of the first connection means and the second connection means can be used in the removal process of rebuilding work. Furthermore, the first connection means can be reused even after permanent installation.

According to the bridge reconstruction method according to the present invention, it is applicable even when the construction conditions under a bridge are severe.

Cross-sectional diagram of the system of the present application Connection mechanism (examples and modifications) Connection mechanism (modified example) Perspective view of existing superstructure removal example (first half) Perspective view of example of removal of existing superstructure (second half) Perspective view of existing substructure removal example Perspective view of new superstructure construction example Perspective view of newly constructed bridge example Perspective view of existing superstructure removal example (modified example) Perspective view of existing superstructure removal example (modified example) Perspective view of existing superstructure removal example (modified example) Perspective view of existing bridge example

～Existing bridge example～
FIG. 12 is an example of an existing bridge 10 to which the present invention is applied. In urban areas, a plurality of railways run parallel to each other in narrow valleys, and bridges 10 are built to span the valleys and intersect with the railroad tracks. Existing bridges generally have short spans, and a superstructure (a broad concept including bridge girders and deck slabs) 11 is supported by lower structures of abutments 12, 12 and piers 13, 13 at both ends. Note that illustrations of other components such as supports are omitted. A plurality of railways are passing between the piers 13 and 13 or between the abutments 12 and 13.

Reconstruction work is complicated because the removal process and new installation process are intertwined. In addition, when rebuilding a bridge, it is necessary to consider the railway operating conditions. For example, even if bridge reconstruction work is carried out at night when trains are not operating, it takes time to bring in and remove materials and equipment, and temporary equipment must be removed each time, making it virtually difficult to work under the bridge. .

Under the above construction conditions, it is preferable that there be as little work under the bridge as possible.

～Characteristic composition～
The rebuilding method according to this embodiment is performed by a system having a characteristic configuration.

FIG. 1 is a cross-sectional view of the system. This system includes a connection mechanism 30 that connects the existing bridge 10 (see FIG. 12) and the new bridge 20 (see FIG. 8). The connection mechanism 30 is formed by connecting the first connection means 31 and the second connection means 32.

The first connecting means 31 has a structure that extends in the bridge axis direction in the form of a rail. Two first connecting means 31, 31 extend in the bridge axis direction on the lower surface side of the newly constructed bridge superstructure 21 (see FIG. 4, which will be described later).

The second connecting means 32 is a hanging rod. The hanging rod 32 has one end connected to the existing object to be removed so that it can be suspended and supported, and the other end connected to the first connecting means 31 so as to be able to slide on the first connecting means 31 . The length of the hanging rod 32 can be adjusted to lift up the existing object to be removed.

In the example of FIG. 1, the hanging rod 32 consists of an upper hanging rod 33 and a lower hanging rod 34.

The upper end of the hanging rod 33 is slidably connected to the first connecting means 31. The lower end of the hanging rod 33 is coupled to a hanging beam 35. The connection mechanism between the first connection means 31 and the hanging rod 33 is a fitting structure using, for example, a JES joint.

FIG. 2A is a JES joint, which is an example of a connection mechanism. JES joints have a C-shaped cross section with a knob at one end, and the joints are fitted together by inserting the knobs into each other's C-shaped spaces. FIG. 2B shows a modification of the connection mechanism. A cylindrical engagement portion at the upper end of the hanging rod 33 slides within the first connecting means 31 having a space with a horseshoe shape in cross section. The suspension rod 33 may have a width in the bridge axis direction.

FIG. 3 shows another modification of the connection mechanism. A groove 31 extends in the bridge axis direction on the lower surface side of the newly constructed bridge superstructure 21. In other words, the first connecting means 31 having a groove is buried in the lower surface side of the newly constructed bridge superstructure 21 so as to extend in the bridge axis direction.

The upper end of the hanging rod 34 is engaged with a hanging beam 35 via a jack 36. The lower end of the suspension rod 34 is engaged with the existing object to be removed via a fastener 37 provided on the lower surface of the existing object to be removed (for example, the removed portion 11A of the existing bridge superstructure).

In addition, by replacing the engagement with the fasteners 37 with connection using post-installed anchors, the work under the bridge can be reduced as much as possible.

The suspension girder 35 is arranged so that its longitudinal direction is perpendicular to the bridge axis, and the connection mechanisms 30 are provided at two locations on both ends of the suspension girder 35. That is, the suspension rods 32, 32 are connected via the suspension girder 35. By using the hanging girder 35, the hanging position of the existing equipment to be removed can be adjusted.

The jack 36 is, for example, a center hole jack. By tensioning the lifting rod 34 with the jack 36, the existing object to be removed can be lifted up.

The interaction between each component will be explained in the rebuilding procedure.

～Reconstruction work procedure～
4 and 5 are perspective views of an example of removing the existing superstructure. The rebuilding work includes a removal process and a new installation process. In particular, the present procedure is characterized in that the removal process and the new installation process are interlocked with each other.

A new bridge superstructure 21 is constructed in advance outside the existing bridge superstructure 11. Erection girders may be extended at both ends so that the girder length can be adjusted. The new bridge superstructure 21 is carried in using the upper surface of the existing bridge superstructure 11 as a transport path.

Alternatively, the components of the new bridge superstructure 21 may be brought in from outside the existing bridge superstructure 11, and the new bridge superstructure 21 may be constructed on the top surface of the existing bridge superstructure 11. Note that the delivery of the newly constructed bridge superstructure 21 also includes the delivery of component parts.

Temporary vents 41, 41 are provided at both ends of the existing bridge superstructure 11 and in the ground (shown as semi-transparent) on both sides of the existing bridge abutment 12 in the direction perpendicular to the bridge axis. In addition, by widening the interval between the temporary vents 41 and 41, it becomes easier to access the upper surface of the existing bridge superstructure 11.

The new bridge superstructure 21 is temporarily installed on top of the existing bridge superstructure 11 by jacking it up while temporarily supporting both ends of the new bridge superstructure 21 with the temporary vents 41 , 41 . Note that the width of the new bridge superstructure 21 is made wider than the width of the remaining bridge superstructure 11 of the existing bridge.

Next, the existing bridge superstructure removal equivalent portion 11A and the new bridge superstructure 21 are connected via the connection mechanism 30 in the existing bridge superstructure removal equivalent portion 11A (see FIG. 1). As a result, the existing bridge superstructure removed portion 11A is suspended and supported by the new bridge superstructure 21. Note that from the viewpoint of stability, long objects are generally suspended from four or more points (see Fig. 4).

In the suspended and supported state, the portion 11A corresponding to removal of the existing bridge superstructure is cut to form a removal block. The removed block 11A is lifted up using the jack 36, so that the lower surface of the removed block 11A is higher than the upper surface of the remaining part of the existing bridge superstructure 11B (see FIG. 4). Thereby, the removal block 11A becomes slidable.

The unloading cart 42 is kept on standby in the remaining portion of the existing bridge superstructure 11B adjacent to the portion 11A corresponding to removal of the existing bridge superstructure. The removal block 11A is slid through the first connecting means 31, and the removal block 11A is lowered onto the carry-out cart 42 through the jack 36 (see FIG. 5).

The upper surface of the remaining part 11B of the existing bridge superstructure is used as a transportation route for the carrying cart 42, and the removed block 11A is carried out. At this time, if the space between the temporary vents 41 and 41 is sufficiently wide, the material can be carried out from between the temporary vents 41 and 41.

FIG. 6 is a perspective view of an example of removing the existing lower structure. If a part of the existing bridge superstructure removal equivalent part 11A is carried out and an opening is made, it will be possible to access the existing bridge pier removal equivalent part 13A from above.

As a result of connecting the existing bridge pier removal equivalent portion 13A and the new bridge superstructure 21 via the connection mechanism 30, the existing bridge pier removal equivalent portion 13A is suspended and supported by the new bridge superstructure 21. Note that it may be supported at two points as shown in the figure.

In the suspended support state, the existing bridge pier removal equivalent portion 13A is cut to form a removal block. The removal block 13A is slid and carried out via the first connecting means 31 in the same manner as the removal block 11A was carried out.

The procedure for carrying out the removal block 11A and the removal block 13A is repeated to remove the existing bridge superstructure remaining portion 11B and the existing bridge pier remaining portion 13B.

FIG. 7 is a perspective view of an example of constructing a new superstructure. With the existing bridge superstructure 11 and the existing bridge piers 13 all removed, the connection between the first connecting means 31 and the second connecting means 32 is released, and the second connecting means 32 is removed. Then, the new bridge superstructure 21 is jacked down while temporarily supporting both ends of the bridge superstructure 21 using the temporary vents 41, 41. Remove the girders at both ends to adjust the girder length. The new bridge superstructure 21 is lowered and permanently installed at a predetermined position on the existing bridge abutments 12, 12.

～Effect～
To summarize the above procedure, it is a repetition of suspension support of the object to be removed → cutting → lifting → sliding → lifting and lowering to the top surface of the existing bridge superstructure → carrying out. In the above procedure, in principle, there is no work under the bridge, and most of the work can be performed using the top surface of the existing bridge superstructure 11.

In other words, rebuilding work can be carried out without being affected by railway operating conditions. However, due to safety concerns in construction, it is believed that the work will actually be carried out at night when there are no trains running. However, even if construction is limited to nighttime work, preparatory work can be done on the top of the existing bridge superstructure while trains are in operation, and there is no need to carry materials and equipment onto the tracks or perform temporary construction, significantly shortening the construction period and ensuring safety. It is expected that the performance will be ensured, and as a result, the cost will be reduced.

In addition, the removal process and the new installation process are interlocked, in other words, the temporarily supported state of the newly constructed bridge superstructure 21 can be used as temporary equipment for the removal of the existing bridge superstructure 11 and the existing bridge pier 13, so this also applies in this respect. It is expected to shorten the construction period and reduce costs.

In this way, the rebuilding method according to the present embodiment is applicable even when construction conditions under a bridge are severe, such as when a plurality of railways run parallel to each other in the bridge crossing direction.

~Using the first connection method after installation~
FIG. 8 is an example of a newly constructed bridge 20 rebuilt according to the present invention. Although the second connecting means 32 of the connecting mechanism 30 is removed, the first connecting means 31 remains installed on the lower surface side of the newly constructed bridge superstructure 21 even after the permanent installation. That is, the first connecting means 31 is a part of the newly constructed bridge 20.

When inspecting or maintaining the lower surface of the newly constructed bridge superstructure 21, the first connecting means 31 is used to suspend and slide a working gondola (not shown). This greatly reduces the need for temporary construction for inspection and maintenance, making inspection and maintenance easier.

～Variation example～
In order to facilitate understanding of the present invention, the above embodiment has been described as an example; however, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical idea of the present invention.

FIG. 9 is a perspective view of a modified example of removing the existing superstructure. In the embodiment described above, the removal block 11A is lifted up (see FIG. 4), then slid and lowered onto the carry-out cart 42 (see FIG. 5), and the upper surface of the remaining part 11B of the existing bridge superstructure is used as a transport path for the carry-out cart 42. On the other hand, in the modified example, after lifting the removal block 11A (see FIG. 4), it is slid to the end of the first connecting means 31, lowered, and carried out from the end of the existing bridge 10.

That is, in the modified example, the upper surface of the existing bridge superstructure remaining portion 11B is not used as a transport path. As a result, the upper surface of the existing bridge superstructure remaining portion 11B can be effectively used as a work space, further improving workability and safety.

FIG. 10 is a perspective view of another modified example of removing the existing superstructure. In the above embodiment, the existing bridge superstructure 11 and the existing bridge piers 13 are removed and the existing bridge abutments 12 are reused, whereas in the modified example, the existing bridge abutments 12 are also removed and new bridge abutments 22 are provided.

First, new abutments 22, 22 are provided outside the existing abutments 12, 12 in the bridge axis direction. Temporary vents 41, 41 are provided on the newly constructed bridge abutments 22, 22 to temporarily support both ends of the newly constructed bridge superstructure 21.

In the procedure for carrying out the removal block 11A and the removal block 13A, the existing bridge abutment 12 is cut to form a removal block, and the removal block is slid and carried out via the first connecting means 31. At this time, by sliding the removed block to the new abutment 22 and carrying it out from the new abutment 22, the entire remaining portion 11B of the existing bridge superstructure can be effectively used as a work space.

With the existing bridge superstructure 11 and the existing bridge superstructures 12 and 13 all removed, the new bridge superstructure 21 is lowered and permanently installed at a predetermined position on the new bridge abutments 22 and 22.

In addition, by making the width of the new bridge abutment 22 wider than the width of the existing bridge abutment 12, and making the width of the new bridge superstructure 21 wider than the width of the remaining part 11B of the existing bridge superstructure, a wide unloading space can be secured and construction efficiency is further improved.

FIG. 11 is a perspective view of another modified example of removing the existing superstructure. After lifting the removed block 11A, it is slid and lowered onto the remaining portion of the existing bridge superstructure 11B adjacent to it, and is divided into small pieces on the remaining portion of the existing bridge superstructure 11B and carried out.

Although the example of the existing bridge shown in FIG. 12 is based on the existence of the existing bridge piers 13, the present invention can also be applied to existing bridges without piers. In that case, the process of removing the existing pier 13 is naturally unnecessary. That is, in the present invention, removal of the existing pier 13 is not essential.

By the way, existing bridges built more than half a century ago generally have short span lengths, but we have examined the cross-sectional structure and materials, and have used modern technology as appropriate, such as using PC bridges, arch bridges, cable-stayed bridges, and suspension bridges. By using it, the span length of new bridges can be increased. As a result, new piers are not required.

In the above embodiment, as an example of severe construction conditions under a bridge, the case where multiple railways run parallel in the direction of crossing the bridge (see Fig. 12) was given, but there are also cases where major arterial roads intersect under the bridge. It is also suitable in cases where rivers intersect and the current is fast and it is difficult to anchor the barge.

In the example of the existing bridge shown in FIG. 12, it is a road bridge, but it may also be a railway bridge.

10 Existing bridge 11 Existing bridge superstructure 12 Existing bridge abutment (substructure)
13 Existing pier (substructure)
20 New bridge 11 New bridge superstructure 12 Existing bridge abutment (substructure)
30 Connection mechanism 31 First connection means (rail type)
32 Second connection means (hanging rod)
33 Upper hanging rod 33 Lower hanging rod 35 Hanging girder 36 Jack 37 Fastener 41 Temporary vent 42 Carrying out trolley

Claims (6)

The existing bridge superstructure is supported by the existing bridge substructure.
A first connection means extending in the bridge axis direction is provided on the lower surface side of the new bridge superstructure,
Transporting the new bridge superstructure using the top surface of the existing bridge superstructure as a transportation route,
Temporarily installing the new bridge superstructure on top of the existing bridge superstructure, temporarily supporting both ends of the new bridge superstructure,
connecting the first connecting means and the second connecting means, and suspending and supporting the removed portion of the existing bridge superstructure on the new bridge superstructure via the second connecting means;
Cut off the portion of the existing bridge superstructure that corresponds to the removal,
Lifting up a portion of the existing bridge superstructure that corresponds to removal, and further sliding it through the first connecting means and removing it;
Repeating the removal of the portions of the plurality of existing bridge superstructures that correspond to the removal, and removing the existing bridge superstructures;
A construction method in which the newly constructed bridge superstructure is lowered and permanently installed,
The remaining part of the existing bridge superstructure is supported by the existing bridge substructure,
In the removal of the portion equivalent to the removal of the existing bridge superstructure,
suspended over the remainder of the existing bridge superstructure;
The upper surface of the remaining portion of the existing bridge superstructure will be used as the transportation route.
A bridge reconstruction method characterized by: The existing bridge superstructure is supported by the existing bridge substructure.
A first connection means extending in the bridge axis direction is provided on the lower surface side of the new bridge superstructure,
Transporting the new bridge superstructure using the top surface of the existing bridge superstructure as a transportation route,
Temporarily installing the new bridge superstructure on top of the existing bridge superstructure, temporarily supporting both ends of the new bridge superstructure,
connecting the first connecting means and the second connecting means, and suspending and supporting the removed portion of the existing bridge superstructure on the new bridge superstructure via the second connecting means;
Cut off the portion of the existing bridge superstructure that corresponds to the removal,
Lifting up a portion of the existing bridge superstructure that corresponds to removal, and further sliding it through the first connecting means and removing it;
Repeating the removal of the portions of the plurality of existing bridge superstructures that correspond to the removal, and removing the existing bridge superstructures;
A construction method in which the newly constructed bridge superstructure is lowered and permanently installed,
The remaining part of the existing bridge superstructure is supported by the existing bridge substructure,
In the removal of the portion equivalent to the removal of the existing bridge superstructure,
Pass it over the remaining part of the existing bridge superstructure in a sliding state and carry it out to the outside of the existing bridge.
A bridge reconstruction method characterized by: suspending and supporting the removed portion of the existing bridge lower structure on the new bridge upper structure via the second connection means;
Cut off the portion of the existing bridge substructure that corresponds to the removal,
Lifting up a portion of the existing bridge substructure equivalent to removal, further sliding it via the first connecting means, and removing it;
3. The bridge reconstruction method according to claim 1, wherein the existing bridge substructures are removed by repeatedly removing portions of a plurality of the existing bridge substructures. The second connecting means is provided at least two in a direction perpendicular to the bridge axis,
4. The bridge reconstruction method according to claim 1 , wherein the second connecting means are connected to each other via a hanging girder. 5. The bridge reconstruction method according to claim 1, wherein the first connecting means remains installed even after the new bridge superstructure is permanently installed. 6. The method for rebuilding a bridge according to claim 1, wherein the existing bridge superstructure is installed on a railroad or road extending in a direction crossing the bridge axis.