JP2017057701A - Concrete wall structure for reinforcing fill-integrated bridge, and construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable tensile stress of a girder to become lower than ever, while keeping girder height low, and enable an improvement in workability.SOLUTION: A concrete wall structure is constructed by a step of integrally providing an abutment 4 on a side surface of reinforcing fill 2, a step of loading an end 3a of a PC bridge girder 3 on a girder joint 42 of the abutment 4, and a step of forming a joint 7 positioned in an upper part of the abutment 4 in the state of separation from reinforcing fill 2, in a predetermined area between the PC bridge girder 3 and the reinforcing fill 2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a concrete wall structure and a construction method in a reinforced embankment-integrated bridge whose back portion is formed on embankment.

  Conventionally, when building a bridge in a river or road intersection, first, a foundation pile is placed on the supporting ground (if the supporting ground is strong, the foundation pile may be unnecessary), and then the abutment Build up. After that, the embankment is built on the back of the abutment, fixed and free bearings are installed on the abutment, and the bridge girder is constructed between the abutments. Here, the abutment resists earth pressure due to embankment, and has a function of supporting a girder's own weight or a train mounted on the girder as a girder's girder.

As a high-performance bridge structure that can solve various problems at the boundary between the embankment and the bridge, for example, a reinforced embankment integrated bridge in which a bridge girder and an abutment are integrated as described in Patent Document 1 is known.
In Patent Document 1, in the construction method of bridges, a reinforced embankment is constructed using geotextiles and sandbags according to the procedure of the reinforced earth wall method, and when the supporting ground is soft, ground subsidence by raising the reinforced embankment When the foundations such as foundation piles are built, the reinforcement embankment is constructed on the facing side using geotextiles and sandbags. If the supporting ground is soft, the reinforcement embankment 4 is raised. Describes a structure in which foundation foundations such as foundation piles are constructed at the stage when land subsidence due to grounding has converged, and the above-mentioned facing embankment wall surface work and the beam part of the bridge girder are integrated, and reinforced concrete is placed in the ramen bridge part Has been.

Japanese Patent No. 4863268

  However, conventional reinforced embankment-integrated bridges, for example, are intended for short span bridges with a length of 20 m or less, and there is a need for long span technology, omitting bearings, measures for settlement of backfill, and high earthquake resistance. It is possible to ensure. However, since the expansion and contraction of the bridge is constrained by the integration of the reinforcing embankment and the bridge, the constant static destabilizing force acting on the bridge increases. Since the static instability accompanying the expansion and contraction of such bridges increases as the span length increases, the verification of bending cracks on the lower surface of the center of the span due to the accompanying tensile stress of the girder can be satisfied by design. Even if the PC structure is applied, it is difficult to construct a long span reinforced embankment integrated bridge.

  In addition, as countermeasures for cracks, it is possible to increase the girder height and increase the cross-sectional rigidity. However, the construction cost increases and the problem that the girder height limitation is hindered by increasing the girder height was there.

The present invention has been made in view of the above-described problems, and provides a concrete wall structure and a construction method in a reinforced embankment-integrated bridge capable of reducing the tensile stress of a girder as compared with the conventional one while suppressing the girder height. With the goal.
Moreover, the other object of this invention is to provide the concrete wall structure in the reinforcement embankment integrated bridge which can improve workability | operativity.

  In order to achieve the above object, the concrete wall structure in the reinforced embankment-integrated bridge according to the present invention is a concrete wall structure provided on the side of the reinforced embankment at both ends of the bridge and on which the end of the PC bridge girder is placed. And the predetermined area | region which is the upper part of the said concrete wall and includes the part in which the said PC bridge girder is mounted is formed separately from the said reinforcement embankment, It is characterized by the above-mentioned.

  Further, the concrete wall structure construction method according to the present invention is the concrete wall structure construction method described above, wherein the step of constructing the reinforcing embankment and the predetermined region of the concrete wall are removed from the side of the reinforcing embankment. From the reinforcing embankment to the predetermined region between the PC bridge girder and the reinforcing embankment, the step of integrally providing other parts, the step of placing the end of the PC bridge girder on the concrete wall, And a step of forming a joint located above the concrete wall in a separated state.

  In the concrete wall structure in the reinforced embankment-integrated bridge according to the present invention, the region in which the reinforced embankment and the bridge are integrated is changed, and in a predetermined region including a portion on which the PC bridge girder is placed on the upper part of the concrete wall, A structure with a non-integrated region that is non-joined, and at the bottom of the bridge, a structure in which the reinforcement embankment on the back side and the bridge are joined together, so that the reinforcement material for the reinforcement embankment on the back of the bridge The static destabilizing force of the bridge that increases due to the restraining action can be suppressed.

In this way, by changing the range in which the reinforced embankment and the bridge are integrated, the restriction of the bridge by the embankment reinforcing material can be relaxed, and the tensile stress due to the static instability acting on the PC bridge girder is reduced. be able to.
In addition, for the lower part of the bridge, by integrating the reinforcement embankment on the back side and the bridge, it is possible to expect the passive resistance of the back embankment while ensuring the stability as an integral structure, and also ensure earthquake resistance can do.
Furthermore, in the present invention, even if it is a non-integrated part, it is possible to make the reinforcing embankment on the back side a part of the outer formwork, so that the workability can be improved and the construction period can be shortened and the construction cost can be reduced. Can be reduced.

  Moreover, as for the concrete wall structure in the reinforcement embankment integrated bridge which concerns on this invention, it is preferable that the said predetermined range is an area | region where the cross section was enlarged rather than the area | region below it.

  In the concrete wall structure in the reinforced embankment-integrated bridge according to the present invention, a rigid wall may be provided on the reinforced embankment adjacent to the predetermined range of the concrete wall.

  In the present invention, the rigid wall and the concrete wall become a non-integrated region, exhibiting the above-described effects, and further, since the rigid wall is integrated with the reinforcing embankment, the stability of the reinforcing embankment can be further increased.

  Moreover, as for the concrete wall structure in the reinforcement embankment integrated bridge which concerns on this invention, the said predetermined range can also be an area | region above the position of the lower surface of the girder of the said PC bridge girder.

  In this case, since the entire concrete wall abutment is joined to the reinforced embankment, the abutment will not tilt when the PC abutment is placed on the abutment, and structural stability during construction will be ensured. be able to.

  According to the concrete wall structure and construction method in the reinforced embankment integrated bridge of the present invention, it is possible to reduce the tensile stress of the girder as compared with the prior art while suppressing the girder height and to improve the workability.

It is a perspective view which shows the structure of the reinforcement embankment integrated bridge in embodiment of this invention. It is a side view of the reinforcement embankment integrated bridge shown in FIG. (A), (b) is a figure which shows the construction procedure of a reinforcement embankment integrated bridge. (A), (b) is a figure which shows the construction procedure of the reinforcement embankment integrated bridge following FIG.3 (b). It is a side view which shows the structure of the reinforcement embankment integrated bridge by the 1st modification of embodiment. It is a side view which shows the structure of the reinforcement embankment integrated bridge by the 2nd modification of embodiment.

  Hereinafter, a concrete wall structure and a construction method in a reinforced embankment integrated bridge according to an embodiment of the present invention will be described based on the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention.

  As shown in FIGS. 1 and 2, the concrete wall structure in the reinforced embankment-integrated bridge according to the present embodiment is formed on the side of the reinforced embankment 2 at both ends of the railway bridge 1 (only one side is shown in FIG. 2). The concrete wall structure provided with the abutment 4 by which the edge part 3a of PC (precast concrete) bridge girder 3 is mounted is provided in the upper part. An RC roadbed 5 made of reinforced concrete is laid on the upper surface of the reinforced embankment 2.

The bridge 1 has a pair of left and right abutments 4 (4A, 4B) located at the boundary between the PC bridge girder 3 and the reinforcing embankment 2. A track 6 including a pair of rails 62 and 62 is laid on the bridge girder 3 and the RC roadbed 5 via a sleeper 61.
Here, the extending direction of the PC bridge girder 3, that is, the direction orthogonal to the back surface 4a of the abutments 4A and 4B is referred to as a bridge axis direction X. In the bridge axis direction X, the direction facing the central part of the extending direction of the PC bridge girder 3 is referred to as the front side and the front side, and the direction facing the reinforcing embankment 2 side is referred to as the back side and the back side.

  The abutment 4 is constructed of reinforced concrete, and is provided integrally with the pile on a pile (not shown) placed on the ground. The abutment 4 includes a wall body 41, a girder joint 42 provided at the upper portion of the wall body 41, and a foundation 43 provided at the lower portion of the wall body 41. The abutment 4 is located between the PC bridge girder 3 and the reinforcing embankment 2, supports the PC bridge girder 3 from below, and against the earth pressure from the back surface 4 a of the abutment 4, the wall body 41 and the foundation of the abutment 4. 43 is formed into a type of abutment that resists. The abutment 4 includes a plurality of embankment reinforcements 44 constructed on the reinforcing embankment 2 and a plurality of anchor reinforcing bars 45 (shown only in some anchor reinforcing bars 45 in FIG. 1). The reinforcement embankment 2 and the abutment 4 are integrally joined.

  The cross-sectional area of the girder joint 42 of the abutment 4 is larger than that of the wall body 41 in a side view shown in FIG. That is, the girder joint 42 has a shape protruding in the bridge axis direction X from the back surface 4a and the front surface 4b.

The end portion 3 a of the PC bridge girder 3 is placed and fixed integrally on the upper surface 4 c of the girder joint portion 42 with the joint portion 7 interposed between the reinforcing embankment 2. The joint portion 7 is made of reinforced concrete, and at the time of construction, the end portion 3a of the PC bridge girder 3 is placed on the abutment 4 so that the end portion 3a of the PC bridge girder 3 and the abutment 4 The girder joint 42 is integrally joined.
Here, the portion (predetermined area) including the joint 7 and the end 3a of the PC bridge girder 3 provided above the abutment 4 of the present embodiment is the “upper part of the concrete wall” of the present invention, that is, the “concrete wall”. It corresponds to a part of.

Further, the back surface 7a side of the joint portion 7 is provided in a state separated from the reinforcing embankment 2, that is, in a non-joined state. A region (length dimension) in the height direction on the back surface side 7a of the joint 7 is referred to as a non-integrated region P1, and a non-integrated height of the non-integrated region P1 is indicated by A. That is, the non-integrated region P <b> 1 according to the present embodiment is a region above the position of the upper surface of the girder joint 42 or a region above the girder lower surface 3 c of the PC bridge girder 3.
On the other hand, as described above, a region where the back surface 4a of the abutment 4 and the reinforcing embankment 2 are joined is referred to as an integrated region P2.
And if the total height of the reinforcement embankment 2 is set to H, the non-integrated height A is set by (1) Formula. That is, the non-integrated region P <b> 1 is configured to have a height that is 1/3 or less of the reinforcing embankment 2.
A ≦ H / 3 (1)

Next, the construction method of the concrete wall structure in the reinforcement embankment integrated bridge of the structure mentioned above is demonstrated based on drawing.
As shown to Fig.3 (a), the reinforcement embankment 2 is constructed in the predetermined area | region of the ground G. FIG. The construction range of the reinforcing embankment 2 is appropriately set according to the geological conditions of the ground G, the track conditions, the installation shape of the bridge 1 and the like. In the upper part of the reinforcing embankment 2, a step 2 a is formed in a portion where the girder joint 42 of the abutment 4 is arranged.

Next, as shown in FIG. 3 (b), a reinforced concrete abutment 4 is constructed by placing a concrete frame (not shown) on the front surface (side surface) of the reinforcing embankment 2 with a space therebetween. At this time, the reinforcing embankment 2 and the abutment 4 are integrally joined by the embankment reinforcing material 44 and the anchor reinforcing bar 45 shown in FIG. The girder joint 42 of the abutment 4 is disposed so as to be placed on the stepped portion 2 a of the reinforcing embankment 2.
Thereafter, as shown in FIG. 4A, the PC bridge girder 3 is placed on the girder joint 42. At this time, the PC bridge girder 3 is installed with an interval S between regions where the joint 7 between the end surface 3b and the reinforcing embankment 2 is disposed.

  And after installing the PC bridge girder 3, as shown in FIG.4 (b), concrete is cast in the said space | interval S and the junction part 7 of a reinforced concrete structure is constructed. At this time, for example, an embedding formwork (not shown) having the joint 7 side as a formwork surface is assembled along the front surface 2 b of the reinforced embankment 2, and concrete is placed between the embedding formwork and the PC bridge girder 3. To construct the joint 7. Thereby, the back surface 7a of the joining part 7 and the reinforcement embankment 2 will be in a non-joining state, and the non-integrated area | region P1 is formed.

Next, the action of the concrete wall structure and the construction method in the reinforced embankment-integrated bridge having the above-described configuration will be specifically described.
As shown in FIG.1 and FIG.2, in this Embodiment, the area | region which integrates the reinforcement embankment 2 and the bridge 1 is changed, and it is a predetermined area | region including the part in which the PC bridge girder 3 is mounted in the upper part of a concrete wall. The structure has a non-integrated region P1 that is not joined to the bridge 1, and the reinforcement embankment 2 on the back side and the bridge 1 are joined together in the lower part of the bridge (wall body 41 and foundation 43). With this structure, it is possible to suppress the static destabilizing force of the bridge that increases due to the restraining action of the embankment reinforcing material 44 of the reinforcing embankment 2 on the back of the bridge.

In this way, by changing the range in which the reinforced embankment 2 and the bridge 1 are integrated, the bridge restraint by the embankment reinforcing material can be relaxed, and the tensile stress due to the static instability acting on the PC bridge girder 3 can be reduced. Reduction can be achieved.
Also, at the lower part of the bridge, by integrating the reinforcing embankment 2 on the back side and the bridge 1, it becomes possible to expect the passive resistance of the back embankment while ensuring the stability as an integral structure, and the earthquake resistance Can also be secured.
Furthermore, in the present embodiment, even if it is a non-integrated part, the back side reinforcing embankment 2 can be made a part of the outer formwork, workability can be improved, and the construction period can be improved. Shortening and reduction of construction costs can be achieved.

  In this embodiment, since the entire concrete wall abutment 4 is joined to the reinforced embankment 2, when the PC abutment 3 is placed on the abutment 4, the abutment 4 does not tilt, Structural stability can be ensured.

  In the concrete wall structure and construction method in the reinforced embankment-integrated bridge according to the above-described embodiment, the tensile stress of the girder can be reduced as compared with the conventional one while suppressing the girder height, and the workability can be improved.

The embodiment of the concrete wall structure and the construction method in the reinforced embankment-integrated bridge according to the present invention has been described above, but the present invention is not limited to the above-described embodiment, and is appropriately changed without departing from the scope of the present invention. Is possible.
For example, in the above-described embodiment, the non-integrated region P1 (predetermined range) where the joint 7 and the reinforcing embankment 2 are not joined is set to be a region above the position of the underside 3c of the PC bridge girder 3. However, it is not limited to this position.
That is, the non-integrated region P1 (predetermined range) where the reinforcing embankment 2 is not joined like the reinforcing embankment integrated bridge according to the first modification shown in FIG. 5 has a larger cross section than the region below it. The region, that is, the region above the lower surface of the girder joint 42 of the abutment 4 may be used.

  Further, as in the second modification shown in FIG. 6, for example, a reinforced concrete structure is applied to the reinforcing embankment 2 adjacent to a predetermined range of the concrete wall (here, the back surface of the girder joint portion 42 of the abutment 4 and the back surface of the joint portion 7). The rigid wall 8 which consists of may be provided. In this case, the rigid wall 8 and the concrete wall become a non-integrated region, exhibiting the above-described effects, and further, the rigid wall 8 is integrated with the reinforced embankment 2 so that the stability of the reinforced embankment 2 can be further enhanced. it can.

  In addition, it is possible to appropriately replace the constituent elements in the above-described embodiments with well-known constituent elements without departing from the spirit of the present invention, and the above-described embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 Bridge 2 Reinforcement embankment 3 PC bridge girder 3a End part 4 Abutment 4a Back surface 4b Front surface 4c Upper surface 5 RC roadbed 7 Joint part 7a Back surface 41 Wall body 42 Girder joint part 43 Foundation 44 Embankment reinforcement 45 Anchor reinforcement P1 Unification area P2 integral Area X Bridge axis direction

Claims (5)

A concrete wall structure provided on the side of the reinforced embankment at both ends of the bridge, on which the end of the PC bridge girder is placed,
A concrete wall structure in a reinforced embankment-integrated bridge, wherein a predetermined region including an upper portion of the concrete wall and including a portion on which the PC bridge girder is placed is formed separately from the reinforced embankment.   2. The concrete wall structure in a reinforced embankment-integrated bridge according to claim 1, wherein the predetermined range is a region whose cross section is larger than a region below the predetermined range.   The concrete wall structure in the reinforced embankment-integrated bridge according to claim 2, wherein the reinforced embankment adjacent to a predetermined range of the concrete wall is provided with a rigid wall.   2. The concrete wall structure in a reinforced embankment-integrated bridge according to claim 1, wherein the predetermined range is a region above a position of a lower surface of the PC bridge girder. A concrete wall structure construction method according to any one of claims 1 to 4,
A process of constructing a reinforced embankment;
A step of integrally providing the other side of the reinforced embankment excluding the predetermined region of the concrete wall;
Placing the end of the PC bridge girder on the concrete wall;
Forming a joint located at an upper portion of the concrete wall in a state separated from the reinforcing embankment in the predetermined region between the PC bridge girder and the reinforcing embankment;
A method for constructing a concrete wall structure characterized by comprising:

Images