JP7438441B1 - How to update bridges - Google Patents

Abstract

[Problem] To provide a bridge renewal method that constructs a new embankment structure by closing the space under the floorboard of an existing bridge with a wall and filling the inside with a solidifying material. [Solution] A bridge renewal method 1 of the present invention includes a foundation step S1 in which a foundation concrete 21 is constructed on the ground below a deck plate 12 of a bridge 10, and a placement step S1 in which a steel frame 31 is placed on the foundation concrete 21. S2, a shielding step S3 in which a wall material 32 is attached between the frames of the steel frame body 31 to construct a wall portion 30, and a filling space A shielded by the wall portion 30 is defined in the lower part of the floor plate 12; It is characterized in that it includes a filling step S4 in which the space A is filled with the solidifying material 40, and the entire steel frame 31 is disposed inside the floor plate 12 in the width direction when the bridge 10 is viewed from above. [Selection diagram] Figure 6

Description

The present invention relates to a bridge renewal method, and in particular to a bridge renewal method in which a new embankment structure is constructed by closing the space under the floorboard of an existing bridge with a wall and filling the inside with a solidifying material.

Of the approximately 730,000 bridges that exist across Japan, it is estimated that 10 years from now, the number of bridges that have been constructed for 50 years will rapidly increase to approximately 57% of the total (August 2020). Current state of bridges in Japan: Transition from construction to management era” (Ministry of Land, Infrastructure, Transport and Tourism, Chubu Regional Development Bureau).
As bridges continue to age, damage such as cracks in deck plates and damage to bearings due to repeated overloading, corrosion of steel members due to salt damage, and cracks in concrete due to carbonation may occur, and there is a risk that the original functions of bridges may be impaired. In addition, there are concerns about concrete spalling and parts falling.
As a method for renewing aging bridges, Patent Document 1 discloses that polystyrene resin foam blocks are stacked at the bottom of the bridge, a plurality of steel members are erected at predetermined intervals along the sides of the bridge, and the steel members are A construction method is disclosed in which a reinforced structure integrated with a bridge is constructed by providing a rectangular panel between the blocks and filling the upper part of the polystyrene resin foam block with foamed urethane.
A similar construction method involves erecting multiple H-beams at predetermined intervals along the side of a bridge, installing rectangular wall panels in front of the H-beams, and applying air mortar in the space partitioned by the piers and wall panels. A method of filling the space beneath a bridge and constructing an embankment structure is being implemented (Figure 10).

Japanese Patent Application Publication No. 2016-056595

The conventional technology has the following drawbacks.
<1> Since the H-steel columns penetrate vertically into the ground, the floorboards become a hindrance, making it impossible to erect the columns directly below the floorboards. For this reason, the wall panels have to be arranged in a position set back from the bridge in the width direction, which occupies a large area of land, increasing the cost of acquiring the land.
<2> Due to the setback of the wall panels, the space filled with air mortar expands to both sides in the width direction of the bridge, so the amount of air mortar filled becomes excessive and the material cost increases.
<3> Large heavy machinery is required to penetrate the H steel, which increases construction costs and requires securing land for installing the heavy machinery.
<4> If the H steel is not sufficiently embedded, lateral pressure will be applied to the back side of the wall panel due to filling with air mortar, and there is a possibility that the wall panel will bulge out to the front side.

An object of the present invention is to provide a bridge renewal method for solving the problems of the prior art as described above.

The bridge renewal method of the present invention includes a foundation step in which foundation concrete is constructed on the ground below the deck of the bridge, a placement step in which a steel frame is placed on the foundation concrete, and a wall material between the steel frames. A shielding process in which a wall is constructed by attaching a wall and a filling space shielded by the wall is defined at the bottom of the floor plate, and a filling process in which a solidifying material is filled in the filling space, and the planar surface of the bridge is As seen, the entire steel frame is located inside the floorboard in the width direction.

In the bridge renewal method of the present invention, the steel frame includes an upper steel frame body formed by assembling a plurality of shaped steels in a frame shape, a lower steel frame body formed by assembling a plurality of shaped steels in a frame shape, In the placement step, the lower steel frame may be placed on the foundation concrete, and the upper steel frame may be loaded on the lower steel frame.

In the bridge renewal method of the present invention, the upper steel frame may include a hinge structure in which a vertical section steel is pin-joined to a horizontal section steel.

In the bridge renewal method of the present invention, a plurality of sections may be reinforced by connecting them with a plurality of supports in the arrangement step.

In the bridge renewal method of the present invention, anchor bolts may be buried in the foundation concrete in the foundation step, and the lower part of the steel frame body may be connected to the upper part of the anchor bolt in the placement step.

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

In the bridge renewal method of the present invention, the solidifying material includes a cement-based filler and a foam material, and in the filling step, the filler is filled on the foundation concrete, and the foam material is placed between the filler and the floorboard. May be filled.

The bridge renewal method of the present invention has at least one of the following effects.
<1> Since the structure is such that the wall materials are supported by a steel frame placed on the foundation concrete without using supports, the wall materials can be arranged directly below the floorboards. Therefore, there is no need to acquire land for setback.
<2> Since the space for filling the solidifying material can be accommodated under the floorboard, the amount of filling of the solidifying material can be suppressed to an appropriate amount.
<3> Since there is no need for large heavy machinery to penetrate the pillars, the construction cost is relatively low and it can be easily constructed even in narrow mountain areas and residential areas.
<4> Since the structure is such that the wall materials on both sides of the bridge are connected by a steel frame, it is possible to offset the lateral pressure caused by filling the solidifying material and prevent oozing out.

Explanatory diagram of bridge renewal method Diagram of basic process Explanatory diagram of the wall Explanatory diagram of the placement process (1) Explanatory diagram of the placement process (2) Illustration of the shielding process Explanatory diagram of the filling process Explanatory diagram of embankment structure Explanatory diagram of Example 2 Illustration of conventional technology

Hereinafter, the bridge updating method of the present invention will be explained in detail with reference to the drawings.
In the present invention, "bridge renewal" refers to the work of constructing a new embankment structure by closing the space under the floorboard of an existing bridge with a wall and filling the inside with solidifying material.

[How to update bridges]
<1> Overall configuration (Figure 1)
The bridge updating method is a method of updating the existing bridge 10 and constructing the embankment structure 1.
The bridge updating 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 will be described in which one span is constructed between two adjacent piers 11 at the lower part of the floor plate 12 of the bridge 10. At the end of the bridge 10, construction is performed between the abutments and piers 11. By performing similar work over the entire length of the bridge 10, the entire bridge 10 can be constructed as the embankment structure 1.
In addition, when leaving a passage or a waterway below the bridge 10, the embankment structure 1 can be constructed by constructing only the portion other than the passage or waterway.
The method for updating a bridge is to place a steel frame 31 assembled in advance into a frame shape under the floorboard 12 of the bridge 10 (placement step S2), and attach wall materials 32 to the steel frame 31 to install the steel frame 31 at the bottom of the bridge 10. One feature lies in the configuration of defining the filling space A (shielding step S3).

<1.1> Bridge Bridge 10 is an existing civil engineering structure.
The bridge 10 includes at least piers 11 and floor plates 12.
In this example, an example will be described in which the bridge 10 is a road bridge with a girder bridge structure consisting of a plurality of I-girders. However, the purpose of the bridge 10 is not limited to this, and the purpose of the bridge 10 may be a railway bridge, a pedestrian bridge, or the like. Further, the structure of the bridge 10 may be a rigid frame bridge, a truss bridge, an arch bridge, or the like, and the structure of the girder may be a T girder, a box girder, or the like.

<2> Basic process (Figure 2)
The foundation step S1 is a step of constructing the foundation concrete 21 on the ground below the floorboard 12.
The ground directly below the floorboard 12 is excavated to a predetermined depth, and the foundation concrete 21 is poured into the excavated area after performing work such as laying crushed stone, compaction, pouring concrete, installing formwork, and arranging reinforcing bars. Set up
In this example, a plurality of anchor bolts 22 are buried in the foundation concrete 21, and the heads of the anchor bolts 22 are made to protrude upward from the foundation concrete 21.

<3> Wall (Figure 3)
The wall portion 30 is a structure that shields both sides of the bridge 10 in the width direction and defines a filling space A under the floorboard 12.
The wall portion 30 includes a steel frame 31 and a plurality of wall members 32 attached to the front surface of the steel frame 31 or within the frame of the steel frame 31.

<3.1> Steel frame (Figure 3)
The steel frame 31 is a frame that supports the wall material 32.
In this example, the steel frame 31 is composed of a combination 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 assembling a plurality of section steels B in the horizontal and vertical directions. That is, a plurality of beam members B1 made of section steel B, a plurality of girder members B2 made of section steel B, and a plurality of columns B3 made of section steel B are connected in a frame shape.
The upper steel frame 31a includes a hinge structure C in which a vertical shaped steel B (post B3) is pin-joined to a horizontal shaped steel B (beam member B1 or beam member B2).

<3.2> Wall material (Figure 3)
The wall material 32 is a surface material that shields the side surface of the steel frame 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 31 is embedded in the back surface of the wall material 32.
Further, a reinforcing material (not shown) for fixing in the solidifying 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 can be fixed to the wall material 32 by screwing the other end of the deformed reinforcing bar to an insert on the back surface of the wall material 32.

<4> Placement Step The placement step S2 is a step of placing the steel frame 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 31 is arranged inside the floorboard 12 in the width direction.
In this example, the arrangement step S2 is performed in two stages: installation of the lower steel frame 31b and loading of the upper steel frame 31a.

<4.1> Layout of lower steel frame (Figure 4)
The lower steel frame 31b is installed on the foundation concrete 21. Specifically, the lower steel frame 31b is lifted under the floorboard 12 by a crane and installed on the foundation concrete 21. Alternatively, the lower steel frame 31b may be placed by pulling it horizontally on a rail.
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 the girder B2 and the support column B3 are connected and reinforced by the shoring 33.

<4.2> Arrangement of upper steel frame (Fig. 5)
Subsequently, the upper steel frame 31a is loaded on the lower steel frame 31b. Specifically, the upper steel frame 31a is lifted under the floorboard 12 by a crane and installed on the lower steel frame 31b.
In this example, when the upper steel frame 31a is suspended, the support column B3 is installed on the lower steel frame 31b in a state in which it is expanded horizontally by the hinge structure C. Thereby, the upper steel frame 31a can be easily suspended into the narrow space below the floorboard 12.
After installation, the support column B3 is raised vertically, and the support column B3 is connected and fixed to the beam member B1 or the girder member B2 using the support 33. At the same time, the girder material B2 at the lower part of the upper steel frame 31a is connected by bolts to the girder material B2 at the upper part of the lower steel frame 31b.

<5> Shielding process (Figure 6)
The shielding step S3 is a step of shielding both sides of the floorboard 12 in the width direction with the walls 30 to define a filling space A therein.
A wall material 32 is attached to the support column B3 so as to shield between adjacent support columns B3 of the steel frame body 31 (upper steel frame body 31a and lower steel frame body 31b). Specifically, for example, a metal fitting is fixed to an insert on the back side of the wall material 32, and the metal fitting on the back side of the wall material 32 is locked and fixed to a flange of the support column B3.
In this example, since there is a gap on the side of the pier 11, a portion of the side surface of the steel frame 31 on the pier 11 side is also covered by the wall material 32.
By shielding the entire frame of the steel frame 31 with the wall material 32, a filling space A is defined by the wall portion 30 at the lower part of the floor plate 12. However, the filling space A is not limited to a completely sealed space, and an opening may be provided above the wall portion 30 for filling the solidifying material 40, for example.

<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 example, a cement-based filler 41 and a foam material 42 are used in combination as the solidifying material 40. However, the present invention is not limited to this, and for example, the solidifying 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 foaming material 42. In addition to this, an EPS block or the like may be used in combination.
A pressure feed pipe is inserted into the filling space A through 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 filler 41 to a predetermined height, a foam material 42 is sprayed between the upper part of the filler 41 and the floorboard 12. The foam material 42 expands at the same time as it is sprayed and comes into close contact with 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 to increase the supporting capacity of the lower part of the filling space A, and the cost for ground improvement can be reduced. Furthermore, since the air mortar and the urethane foam are lightweight, it is possible to prevent the wall material 32 from protruding outward due to filling.

<7> Embankment structure (Figure 8)
By solidifying the filling material 41 and foam material 42 in the filling space A, an 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 has a structure in which the entire load of the bridge 10 is supported by the consolidation material 40 rather than by the piers 11 or abutments. Therefore, regardless of the soundness of the piers 11 and abutments, the dead weight of the deck slab 11, the live load of passing vehicles, the dead load of snowfall, and the horizontal load during an earthquake can be borne only by the consolidation material 40.
In addition, since the solidifying material 40 is in close contact with the surface of the pier 11 and the bottom of the floorboard 12, it is possible to block chemical influences from the outside and suppress the progress of deterioration of the floorboard 12 and the pier 11.

[Example of one-way bridge type]
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 closed by the slope D (FIG. 9).
In the case of this example, in the shielding step S3, the open side of the lower part of the floorboard 12 is shielded with the wall material 32, and the opposite side is shielded with the slope D, thereby defining the filling space A.
The other steps are the same as in Example 1, so they will not be described in detail here.

1 Embankment structure 10 Bridge 11 Pier 12 Floor plate 20 Foundation 21 Foundation concrete 22 Anchor bolt 30 Wall 31 Steel frame 31a Upper steel frame 31b Lower steel frame 32 Wall material 33 Shoring 40 Solidifying material 41 Filling material 42 Foaming Material A Filling space B Shaped steel B1 Beam material B2 Girder material B3 Support column C Hinge structure D Inclined surface S1 Foundation process S2 Placement process S3 Shielding process S4 Filling process

Claims (7)

A foundation process in which foundation concrete is constructed on the ground below the bridge deck;
a placement step of placing a steel frame on the foundation concrete;
A shielding step of constructing a wall by attaching a wall material between the frames of the steel frame, and defining a filling space shielded by the wall at the lower part of the floor plate;
A filling step of filling a solidifying material into the filling space,
In a plan view of the bridge, the entire steel frame is disposed inside the floor plate in the width direction,
How to update bridges. The steel frame body is
an upper steel frame body formed by assembling a plurality of shaped steels into a frame shape;
A lower steel frame body formed by assembling a plurality of shaped steels into a frame shape,
In the placement 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. The upper steel frame is characterized by having a hinge structure formed by pin-joining a vertical section steel to a horizontal section steel,
The bridge renewal method according to claim 2. In the arrangement step, the plurality of shaped steels are connected and reinforced with a plurality of shoring structures,
The bridge renewal method according to claim 2 or 3. In the foundation step, anchor bolts are buried in the foundation concrete,
In the arrangement step, the lower part of the steel frame is connected to the upper part of the anchor bolt,
The bridge renewal method according to claim 1. In the shielding step, a reinforcing material for fixing with the solidifying material is attached to the filling space side of the wall material,
The bridge renewal method according to claim 1. The solidifying material includes a cement-based filler and a foaming material,
In the filling step, the filling material is filled on the foundation concrete, and the foaming material is filled between the filling material and the floorboard.
The bridge renewal method according to claim 1.

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