Bridge renewal method

Abstract

To provide a bridge renewal method for newly constructing an embankment structure by closing a space under a floor plate of an existing bridge at a wall part and filling the inside with a solidifying material.SOLUTION: A method 1 for renewing bridges according to the present invention includes base step S1 in which a base concrete 21 is constructed on the ground below a floor plate 12 of bridge 10, arrangement step S2 in which a steel frame body 31 is arranged on the base concrete 21, shielding step S3 in which a wall surface material 32 is additionally provided between the frames of the steel frame bodies 31 to construct wall parts 30, and filling spaces A shielded by the wall parts 30 are defined below the floor plate 12, and filling step S4 for filling the filling space A with a solidifying material 40. In the plan view of the bridge 10, the entire steel frame body 31 is disposed inside the floor plate 12 in the width direction.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a bridge renewal method, and more particularly to a bridge renewal method in which a new embankment structure is constructed by closing off the space under the deck of an existing bridge with a wall and filling the interior with a solidification material. [Background technology]

[0002] Of the approximately 730,000 bridges in Japan, it is said that in 10 years' time the number of bridges that have been in operation for more than 50 years will rapidly reach approximately 57% of the total (August 2022, "The Current State of Japan's Bridges: Transition from the Era of Construction to the Era of Management", Chubu Regional Development Bureau, Ministry of Land, Infrastructure, Transport and Tourism). As bridges age, repeated heavy loads can cause cracks in the decking and damage to bearings, corrosion of steel components due to salt damage, and cracks in concrete due to neutralization, which could impair the bridge's original functions. There are also concerns that concrete could spall and components could fall. As a method for updating deteriorated bridges, Patent Document 1 discloses a construction method in which polystyrene resin foam blocks are laminated on the underside of the bridge, multiple steel members are erected at specified intervals along the side of the bridge, rectangular panels are provided between the steel members, and the top of the polystyrene resin foam blocks is filled with urethane foam, thereby constructing a reinforcing structure that is integrated with the bridge. A similar construction method involves erecting multiple H-shaped steel beams at set intervals along the side of the bridge, installing rectangular wall panels in front of the H-shaped steel beams, and filling the space separated by the pier and the wall panels with air mortar to fill the space underneath the bridge and create an embankment structure (Figure 10). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-056595 A Summary of the Invention [Problem to be solved by the invention]

[0004] The prior art has the following drawbacks: <1> Because the H-shaped steel columns penetrate vertically into the ground, the floor slabs get in the way and the columns cannot be erected directly below the floor slabs. This means that the wall panels have to be set back from the bridge in the width direction, occupying a large area of ​​land, which increases the cost of acquiring the land. <2> Due to the setback of the wall panels, the air mortar filling space expands on both sides of the bridge in the width direction, resulting in an excessive amount of air mortar to be filled, which increases material costs. <3> Large heavy machinery is required to penetrate the H-beams, which increases construction costs and requires securing land for the heavy machinery. <4> If the H-beam is not sufficiently embedded, the air mortar filling will apply lateral pressure to the back of the wall panel, which may cause the wall panel to protrude towards the front.

[0005] An object of the present invention is to provide a bridge renewal method that solves the problems of the conventional technology as described above. [Means for solving the problem]

[0006] The bridge renewal method of the present invention comprises a foundation process of constructing foundation concrete on the ground under the bridge deck, a placement process of placing a steel frame body on the foundation concrete, a shielding process of attaching wall materials between the frames of the steel frame body to construct walls and defining a filling space shielded by the wall parts under the deck board, and a filling process of filling the filling space with solidification material, and is characterized in that, when viewed in a plan view of the bridge, the entire steel frame body is positioned on the inside of the deck board in the width direction.

[0007] In the bridge renewal method of the present invention, the steel frame body comprises an upper steel frame body formed by assembling a plurality of shaped steel beams into a frame shape, and a lower steel frame body formed by assembling a plurality of shaped steel beams into a frame shape, and in the placement process, the lower steel frame body may be placed on the foundation concrete, and the upper steel frame body may be loaded on the lower steel frame body.

[0008] In the bridge renewal method of the present invention, the upper steel frame may have a hinge structure in which a horizontal steel section and a vertical steel section are pin-joined.

[0009] In the bridge renewal method of the present invention, in the placement step, a plurality of steel sections may be connected to each other with a plurality of supports for reinforcement.

[0010] The bridge renewal method of the present invention may include embedding anchor bolts in foundation concrete in the foundation step, and connecting a lower part of the steel frame to an upper part of the anchor bolt in the placement step.

[0011] In the bridge renewal method of the present invention, in the shielding step, a reinforcing material for fixing to the solidification material may be attached to the filling space side of the wall material.

[0012] In the bridge renewal method of the present invention, the solidification material includes a cement-based filler and a foaming material, and in the filling process, the filler is filled on top of the foundation concrete, and the foaming material is filled between the filler and the deck plate. Effect of the Invention

[0013] The bridge renewal method of the present invention has at least one of the following effects. <1> Since the wall materials are supported by a steel frame placed on a concrete foundation without using any supports, the wall materials can be arranged directly under the floor plate, eliminating the need to acquire land for setbacks. <2> Since the filling space for the solidification material can be contained under the floorboards, the amount of solidification material filled can be kept to an appropriate level. <3> Since no large heavy machinery is required to drive the pillars in, construction costs are relatively low and construction can be easily carried out even in narrow mountainous areas or residential areas. <4> Since the wall materials on both sides of the bridge are connected by a steel frame, the lateral pressure caused by filling with solidification material can be offset, preventing overflow. [Brief description of the drawings]

[0014] [Figure 1] Illustration of bridge renewal method [Diagram 2] Diagram of basic process [Diagram 3] Wall section diagram [Figure 4] Diagram of the placement process (1) [Diagram 5] Diagram of the placement process (2) [Figure 6] Shielding process diagram [Figure 7] Explanation of the filling process [Figure 8] Illustration of embankment structure [Figure 9] FIG. 2 is an explanatory diagram of the second embodiment. [Figure 10] Illustration of the prior art DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the bridge renewal method of the present invention will be described in detail with reference to the drawings. In this invention, "bridge renewal" refers to the work of constructing a new embankment structure by sealing off the space under the deck of an existing bridge with a wall and filling the inside with a solidification material. EXAMPLES

[0016] [How to update bridges] <1> Overall configuration (Figure 1) The bridge renewal method is a method in which an existing bridge 10 is renewed and an embankment structure 1 is constructed. The bridge renewal method includes at least a foundation process S1, a placement process S2, a shielding process S3, and a filling process S4. In this example, an example of constructing one span between two adjacent piers 11 under the deck 12 of the bridge 10 will be described. At the end of the bridge 10, construction is performed between the abutment and the pier 11. By performing similar work over the entire length of the bridge 10, the entire bridge 10 can be constructed into an embankment structure 1. In addition, when a passageway or waterway is to be left below the bridge 10, the embankment structure 1 can be constructed by constructing only the parts other than the passageway or waterway. One feature of the bridge renewal method is that a steel frame body 31, which has been assembled in advance into a frame shape, is placed under the deck 12 of the bridge 10 (placement process S2), and a wall material 32 is attached to the steel frame body 31 to define a filling space A under the bridge 10 (shielding process S3).

[0017] <1.1> Bridges The bridge 10 is an existing civil engineering structure. The bridge 10 comprises at least a pier 11 and a deck 12 . In this example, the bridge 10 is a road bridge with a girder bridge structure made up of multiple I-girders. However, the bridge 10 is not limited to this, and may be used as a railway bridge, a pedestrian bridge, or the like. The structure of the bridge 10 may be a rigid frame bridge, a truss bridge, an arch bridge, or the like, and the girder structure may be a T-girder or a box girder, or the like.

[0018] <2> Basic process (Figure 2) The foundation process S1 is a process of constructing foundation concrete 21 on the ground below the floor plate 12. The ground directly below the floor plate 12 is excavated to a specified depth, and after tasks such as laying crushed stone, compacting it, pouring mortar concrete, setting formwork, and arranging reinforcing bars, foundation concrete 21 is poured into the excavated portion. In this example, a plurality of anchor bolts 22 are embedded in the foundation concrete 21 , with the heads of the anchor bolts 22 protruding upward from the foundation concrete 21 .

[0019] <3> Wall (Fig. 3) The wall portion 30 is a structure that shields both sides of the bridge 10 in the width direction and defines a filled space A below the deck 12. The wall portion 30 comprises a steel frame body 31 and a plurality of wall members 32 attached to the front surface of the steel frame body 31 or within the frame of the steel frame body 31 .

[0020] <3.1> Steel frame (Fig. 3) The steel frame 31 is a frame that supports the wall material 32 . In this example, the steel frame 31 is made up of an upper steel frame 31a and a lower steel frame 31b. The upper steel frame 31a and the lower steel frame 31b are formed by horizontally and vertically assembling a plurality of shaped steels B. That is, a plurality of beams B1 made of shaped steel B, a plurality of girders B2 made of shaped steel B, and a plurality of columns B3 made of shaped steel B are connected in a frame shape. The upper steel frame body 31a has a hinge structure C formed by pin-joining a horizontal shaped steel B (beam material B1 or girder material B2) to a vertical shaped steel B (pillar B3).

[0021] <3.2> Wall material (Fig. 3) The wall material 32 is a surface material that shields the side surface of the steel frame body 31. In this example, a concrete wall panel is used as the wall material 32. In this example, an insert for connecting to the steel frame body 31 is embedded in the back surface of the wall material 32 . In addition, a reinforcing material (not shown) for fixing in the solidification material 40 can be attached to the back surface of the wall material 32. The reinforcing material is, for example, a plate bolted to one end of a deformed reinforcing bar, and the other end of the deformed reinforcing bar can be fixed to the wall material 32 by screwing it into an insert on the back surface of the wall material 32.

[0022] <4> Placement process The placement step S2 is a step of placing the steel frame body 31 on the foundation concrete 21. The steel frame body 31 is housed inside the lower part of the bridge 10. That is, in a plan view of the bridge 10, the entire steel frame body 31 is disposed inside the deck 12 in the width direction. In this example, the arrangement step S2 is carried out in two stages: installation of the lower steel frame body 31b and loading of the upper steel frame body 31a.

[0023] <4.1> Layout of the lower steel frame (Fig. 4) The lower steel frame body 31b is placed on the concrete foundation 21. In detail, the lower steel frame body 31b is hoisted under the floor plate 12 by a crane and placed on the concrete foundation 21. Alternatively, the lower steel frame body 31b may be placed by pulling it horizontally on rails. After installation, the girder B2 at the bottom of the lower steel frame 31b is bolted to the anchor bolts 22 of the foundation 20, and the beam B1 or girder B2 is connected to the support B3 with a support 33 for reinforcement.

[0024] <4.2> Arrangement of the upper steel frame (Fig. 5) Next, the upper steel frame 31a is loaded onto the lower steel frame 31b. In detail, the upper steel frame 31a is hoisted under the floor plate 12 by a crane and placed on the lower steel frame 31b. In this example, when suspending the upper steel frame body 31a, the support pillars B3 are installed on the lower steel frame body 31b in a state in which they are expanded horizontally by the hinge structure C. This allows the upper steel frame body 31a to be easily suspended in the narrow space below the floorboards 12. After installation, the support pillars B3 are raised vertically and connected and fixed to the beams B1 or girder B2 with supports 33. At the same time, the girder B2 at the bottom of the upper steel frame 31a is bolted to the girder B2 at the top of the lower steel frame 31b.

[0025] <5> Shielding process (Figure 6) The shielding step S3 is a step of shielding both widthwise sides of the floor board 12 with wall portions 30 to define a filling space A therein. Wall materials 32 are attached to the supports B3 so as to shield the space between adjacent supports B3 of the steel frame body 31 (upper steel frame body 31a and lower steel frame body 31b). In detail, for example, metal fittings are fixed to an insert on the back surface of the wall material 32, and the metal fittings on the back surface of the wall material 32 are engaged and fixed to the flanges of the supports B3. In this example, since there is a gap on the side of the pier 11, the side surface of the steel frame 31 facing the pier 11 is also partially shielded by the wall material 32. By shielding the entire interior of the steel frame body 31 with the wall material 32, a filling space A is defined by the wall portion 30 below the floor plate 12. However, the filling space A is not limited to a completely sealed space, and for example, an opening may be provided above the wall portion 30 for filling with the solidification material 40.

[0026] <6> Filling process (Figure 7) The filling step S4 is a step of filling the filling space A with the solidifying material 40. In this embodiment, a combination of a cement-based filler 41 and a foaming material 42 is used as the solidification material 40. However, the present invention is not limited to this, and for example, the solidification material 40 may be composed of only the foaming material 42. In this example, air mortar is used as the filler 41, and urethane foam is used as the foam material 42. In addition, EPS blocks or the like may be used in combination. A pressure pipe is inserted into the filling space A from an opening provided above the floor plate 12 or the wall portion 30, and the filling material 41 is filled onto the foundation concrete 21. After filling the filling material 41 to a predetermined height, the foam material 42 is sprayed between the upper part of the filling material 41 and the floorboard 12. The foam material 42 expands as it is sprayed, and adheres closely to the lower part of the floorboard 12. In this example, since the air mortar and foamed urethane are extremely lightweight, there is no need for ground improvement work to increase the bearing capacity of the lower part of the filled space A, which can reduce the cost of ground improvement work. In addition, since the air mortar and foamed urethane are lightweight, it is possible to prevent the wall material 32 from protruding outward due to filling.

[0027] <7> Embankment structure (Figure 8) As the filling material 41 and foam material 42 in the filling space A solidify, the embankment structure 1 is constructed in which the bridge 10, the steel frame 31, and the wall material 32 are integrated by the solidifying material 40. The embankment structure 1 is a structure in which the entire load of the bridge 10 is supported not by the piers 11 or abutments but by the consolidation material 40. Therefore, regardless of the soundness of the piers 11 and abutments, the weight of the deck 11, the live load of passing vehicles, the dead load of snowfall, and the horizontal load during earthquakes can be borne only by the consolidation material 40. In addition, by the solidification material 40 adhering to the surface of the pier 11 and the bottom surface of the deck 12, it is possible to block chemical influences from the outside and suppress the progression of deterioration of the deck 12 and the pier 11. EXAMPLES

[0028] [Example of single-pier bridge] The bridge renewal method of the present invention can also be applied to a "single-pier bridge" in which one side in the width direction of the bridge 10 is blocked by an inclined surface D (FIG. 9). In this example, in the shielding step S3, the open side of the lower part of the floor board 12 is shielded by the wall material 32, and the opposite side is shielded by the inclined surface D, thereby defining the filling space A. The other steps are the same as those in Example 1 and will not be described in detail here. [Explanation of symbols]

[0029] 1 Embankment structures 10 Bridges 11 Bridge Pier 12 Floorboards 20 Foundation 21 Foundation Concrete 22 Anchor bolt 30 Wall 31 Steel frame 31a Upper steel frame 31b Lower steel frame 32 Wall materials 33 Shoring 40 Solidification material 41 Filling material 42 Foam material A filling space B-shaped steel B1 Beam material B2 girder material B3 Support C hinge structure D Inclined surface S1 Basic process S2 placement process S3 shielding process S4 Filling process

Claims

1. The foundation process involves constructing foundation concrete on the ground beneath the bridge deck; A placement process of placing a steel frame on the foundation concrete; A shielding process in which a wall portion is constructed by attaching a wall material between the frames of the steel frame body, and a filling space shielded by the wall portion is defined below the floor plate; A filling step of filling the filling space with a solidifying material, In a plan view of the bridge, the entire steel frame body is disposed on the inner side in the width direction of the floor plate. How to update bridges.

2. The steel frame body is An upper steel frame body formed by assembling a plurality of steel segments into a frame shape; A lower steel frame body formed by assembling a plurality of steel segments into a frame shape, In the placing step, the lower steel frame is placed on the foundation concrete, and the upper steel frame is loaded on the lower steel frame. The bridge renewal method according to claim 1.

3. The upper steel frame body is characterized in that it has a hinge structure in which a vertical steel is pin-connected to a horizontal steel. The bridge renewal method according to claim 2.

4. In the arranging step, the plurality of shaped steels are connected to each other with a plurality of supports to reinforce them. The bridge renewal method according to claim 2 or 3.

5. In the foundation step, an anchor bolt is embedded in the foundation concrete, In the placing step, a lower part of the steel frame body is connected to an upper part of the anchor bolt. The bridge renewal method according to claim 1.

6. In the shielding step, a reinforcing material is attached to the filling space side of the wall material to be fixed to the solidification material. The bridge renewal method according to claim 1.

7. The solidification material includes a cement-based filler and a foaming material, In the filling step, the filler is filled on the foundation concrete, and the foam material is filled between the filler and the floor plate. The bridge renewal method according to claim 1.

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