Construction method for arch bridge

Abstract

To provide a construction method for an arch bridge, enabling easy construction of the arch member.SOLUTION: A construction method for an arch bridge of the present invention includes steps of: providing a scaffold 10 at a position corresponding to a lower portion of an arch member 3 of the arch bridge; installing a Melan material 31 having a curve shape according to a shape of the arch member 3 on the scaffold 10; and constructing the arch member 3 by placing concrete 32 in such a manner that the Melan material 31 is embedded. When the concrete 32 is placed, a bottom form 50 of the arch member 3 is supported by the Melan material 31.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for constructing an arch bridge. [Background technology]

[0002] An arch bridge is a bridge that supports vertical loads with arch members. One method of constructing arch members is, for example, to install a general support structure below the arch member, place a formwork on top of it, and pour concrete for the arch member. The general support structure supports the load of the concrete from below when pouring the concrete for the arch member (see, for example, Patent Document 1).

[0003] There is also a method called the Pilon method, in which supports (pillons) are erected on abutments and piers, and the weight of the arch members is supported by diagonal hanging members from the supports, while the arch members are successively erected from the abutments and piers toward the center of the span. In this case, there are cases in which the arch members are completed by wrapping steel melan materials that are hung diagonally from the supports and erected in the air in concrete, and this is also called the Pilon-Melan method (see, for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-186590 A [Patent Document 2] Special Publication No. 60-15763 [Patent Document 3] JP 2000-45231 A Summary of the Invention [Problem to be solved by the invention]

[0005] When constructing arch members using general shoring, the load of the concrete being poured into the arch members must be supported by the shoring, which results in large-scale shoring, longer construction time, and higher construction costs.

[0006] The Pilon method also requires the erection of separate supports for inclined suspension. In addition, when erecting multiple span bridges from multiple piers or abutments at the same time, it is difficult to repurpose the temporary equipment, and the construction costs become high. For this reason, it is difficult to construct bridges in a short period of time.

[0007] The present invention has been made in consideration of the above problems, and has an object to provide a construction method for an arch bridge that can easily construct arch members. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention is a construction method for an arch bridge, comprising the steps of: setting up scaffolding at a position below the arch member of the arch bridge; installing curved melamine material on the scaffolding to match the shape of the arch member; and constructing the arch member by pouring concrete so as to bury the melamine material.

[0009] In the present invention, instead of the general support, a scaffold is constructed, a curved melamine material is installed on the scaffold, and concrete is poured to bury the melamine material, thereby constructing an arch member. In this case, the load during concrete pouring can be supported by the axial force of the melamine material, so the scaffold can be simplified compared to the general support. In addition, since the melamine material can be installed on the scaffold, there is no need for a support to hang the melamine material diagonally and erect it in the air. As a result, the arch member can be constructed easily, and construction time and costs can be reduced.

[0010] It is desirable to support the bottom formwork of the arch member from the Mellan material when pouring the concrete. This allows the load when pouring concrete into the arch member to be supported by the axial force of the Mellan material, without the scaffolding bearing the load.

[0011] The bottom formwork is placed on a support girder, and before installing the Mellan material, it is desirable to install on the scaffolding a unit that integrates the support girder and a stand for positioning the support girder in accordance with the inclination of the arch member. This makes it easy to install beams and other components for positioning the bottom formwork.

[0012] It is desirable to span between the piers supporting both ends of the arch member a tension member that introduces tension and a compression member that bears compression, so that the compression force of the tension member resists the horizontal force generated in the pier when the concrete is poured, and the compression member keeps the spacing of the piers constant against the compression force. This makes it possible to prevent cracks in the piers and other structures caused by the horizontal force, and also makes it possible to maintain constant spacing between the piers against the compressive force. Effect of the Invention

[0013] The present invention makes it possible to provide a construction method for an arch bridge that can easily construct arch members. [Brief description of the drawings]

[0014] [Figure 1] A diagram showing arch bridge 1. [Diagram 2] 4A to 4C are diagrams showing the construction procedure of the arch member 3. [Diagram 3] FIG. 4 is a diagram showing an example of a unit 40. [Figure 4] 4A to 4C are diagrams showing the construction procedure of the arch member 3. [Diagram 5] FIG. [Figure 6] A diagram showing a tendon 60 and a compression member 70. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0016] (1. Arch Bridge 1) Fig. 1 is a simplified diagram showing an arch bridge 1 constructed using a construction method according to an embodiment of the present invention. The arch bridge 1 of this embodiment is a bridge with multiple spans, and Fig. 1 shows the central span of the bridge.

[0017] In the arch bridge 1, arch members 3 are provided between piers 2, and superstructure 5 such as stiffening girders is supported by vertical members 4 rising from the arch members 3. In this embodiment, the arch members 3 are made of reinforced concrete (RC). In addition to reinforcing bars, melamine materials (described later) are also embedded in the concrete of the arch members 3.

[0018] In the side spans of the arch bridge 1, the arch members 3 are provided between the piers 2 and abutments (not shown), and in a single-span arch bridge 1, the arch members 3 are provided between the abutments, but the rest of the configuration is approximately the same as above. In this invention, the piers 2 and abutments correspond to the supports that support both ends of the arch members 3.

[0019] (2. Construction method of arch bridge 1) When constructing the arch bridge 1, the arch member 3 is constructed between the piers 2. Figures 2 and 4 are diagrams showing the procedure for constructing the arch member 3 between the piers 2.

[0020] In this embodiment, when constructing the arch member 3, first, a temporary scaffolding 10 is constructed between the piers 2 as shown in Fig. 2(a). The scaffolding 10 has a working floor 13 and columns 12 supporting the working floor 13 on a floor section 11 erected between the piers 2. The scaffolding 10 is supported from below by a temporary intermediate support stand 20 installed between the piers 2.

[0021] Next, as shown in Fig. 2(b), a support stand 30 and the like are installed on the floor 11 of the scaffolding 10 or the work floor 13, and as shown in Fig. 2(c), a unit 40 is installed on the support stand 30. Some of the support stands 30 are also provided with a temporary support part 301 for temporarily supporting the melamine material described later.

[0022] 3 is an example of the unit 40, and shows a side view of the unit 40. The unit 40 is formed by assembling a support beam 41, a cross beam 42, and a temporary frame 43 on the ground.

[0023] The support girder 41 is a member for placing the bottom formwork of the arch member 3 on top of it, and the cross girder 42 is a member for supporting the support girder 41 from below. The temporary mounting stand 43 is a mounting stand for placing the support girder 41 in a direction that matches the inclination of the arch member 3 (direction in the vertical plane), and is made of steel material or the like.

[0024] The support girders 41 are girder materials that run along the bridge axis direction of the arch bridge 1, and multiple ones are arranged in parallel with gaps in the direction perpendicular to the bridge axis of the arch bridge 1. The bridge axis direction of the arch bridge 1 corresponds to the left-right direction in Figure 3, and the direction perpendicular to the bridge axis corresponds to the normal direction to the page in Figure 3. The cross girders 42 are girder materials that run along the direction perpendicular to the bridge axis of the arch bridge 1, and multiple ones are arranged in parallel with gaps in the bridge axis direction of the arch bridge 1. Steel materials such as H-shaped steel are used for the support girders 41 and cross girders 42.

[0025] In this manner, in this embodiment, by assembling the support girder 41, cross girder 42, and temporary mounting base 43 on the ground and forming them into a unit, dangerous work such as tightening bolts at high altitudes can be reduced, and the unit 40 can be easily removed after the arch member 3 is constructed.

[0026] In this embodiment, next, as shown in Fig. 4(a), the melan material 31 constituting the arch member 3 is installed on the scaffolding 10. The melan material 31 is a curved steel member, and its curved shape corresponds to the shape of the arch member 3. The melan material 31 is temporarily supported on the scaffolding 10 by the temporary support part 301 and the like.

[0027] Fig. 5 is a diagram showing the Mellan material 31. The Mellan material 31 has a configuration in which a plurality of (five in the example of Fig. 5) main girders 311 arranged in parallel are connected by steel connecting members 312.

[0028] The main girder 311 is a member that extends in the bridge axis direction of the arch bridge 1, and multiple members are arranged at intervals in the direction perpendicular to the bridge axis. In the vertical plane, the main girder 311 has a curved shape that matches the shape of the arch member 3. The main girder 311 is a box-shaped steel member, and its interior will be filled with filler concrete in a later process.

[0029] In this embodiment, a number of Melang materials 31 (three in the example of FIG. 4(a)) are arranged continuously between the piers 2 in the bridge axis direction of the arch bridge 1, and the Melang materials 31 are erected in sequence from the pier 2 side to the center of the span. The main girders 311 of the Melang materials 31 adjacent to each other in the bridge axis direction are fixed to each other with bolts or the like, and the end of the main girder 311 on the pier 2 side of the Melang material 31 on the pier 2 side is fixed to the pier 2. This fixing can be performed, for example, by inserting a steel rod protruding from the pier 2 into an insertion part (not shown) of the main girder 311 and filling the insertion part with a filler, but is not limited to this.

[0030] Once the Mellan material 31 is erected as described above, the temporary support portion 301 can be removed, after which the inside of the main girder 311 is filled with filler concrete. The filler concrete is filled through a filling hole (not shown) on the top surface of the main girder 311. Since it is difficult to compact the concrete inside the main girder 311 using a vibrator, it is desirable to use high-fluidity concrete, which does not require compaction, as the filler concrete. In addition to the filling holes, multiple holes (not shown) for venting air and checking filling are also arranged around the filling holes on the top surface of the main girder 311.

[0031] Thereafter, as shown in FIG. 4(b), the bottom formwork 50 of the arch member 3 is placed, and other formwork (side formwork, etc.) of the arch member 3 and reinforcing bars (not shown) of the arch member 3 are placed.

[0032] The bottom formwork 50 is installed on the support girders 41 (see FIG. 3). The support girders 41 and cross girders 42 of the unit 40 in FIG. 3 function as supports for the bottom formwork 50, and the support girders 41 and cross girders 42 are suspended and supported by rods 33 such as PC steel bars extended from the melamine material 31, so that the bottom formwork 50 can be supported from the melamine material 31 via these supports. In this embodiment, since it is difficult to install the support girders 41 etc. after the bottom formwork 50 is installed, the support girders 41 etc. are installed in advance by the installation process of the unit 40 described above (see FIG. 2(c)).

[0033] In the center of the span, the support girders 41 and cross girders 42 are pre-assembled as unit U (see Fig. 4(a)) on the work floor 13, and this unit U is lifted up and installed as shown in Fig. 4(b) and suspended from the melamine material 31 by rods 33 such as PC steel bars. A bottom formwork 50 is then installed on the support girders 41 of unit U. This allows the space above the work floor 13 in the center of the span to be used as various yards when pouring concrete for the arch member 3. In the center of the span, the bottom formwork 50 and the support girders 41 of unit U are set up horizontally.

[0034] 4(c), concrete 32 is poured on the bottom formwork 50 so as to bury the melamine material 31. The concrete 32 is poured successively from both piers 2 sides toward the center of the span, and finally the concrete 32 is poured in the center of the span (the closure portion), thereby constructing the arch member 3 of the arch bridge 1.

[0035] The mellan material 31 functions as a support that supports the load of the concrete 32 by axial force (arch axial force) when the concrete 32 is poured. Therefore, there is no need to use a general support below the arch member 3 as described above, and a scaffolding 10 with a simpler structure than a general support can be used, and the number of intermediate supports 20 can also be reduced.

[0036] However, when concrete for the arch member 3 is poured, the axial force generated in the melamine material 31 acts as a horizontal force on both piers 2, causing deformation in both piers 2 that pushes the space between the piers 2 apart. If this deformation becomes too large, there is a concern that cracks will occur in the concrete of the piers 2, etc.

[0037] To prevent this, in this embodiment, before pouring the concrete 32, it is desirable to introduce tension by suspending multiple tension members 60 such as PC steel bars connecting the piers 2 as shown in Figure 6, and also suspend multiple compression members 70 such as H-shaped steel that bear the compressive force between the piers 2 to form a tied arch.

[0038] By forming a tied arch, the compressive force of the tendons 60 provides both piers 2 with resistance to the above-mentioned deformation, while the presence of the compression members 70, which function as braces, prevents the gap between both piers 2 from narrowing due to the compressive force. The timing for introducing tension into the tendons 60 is determined at an appropriate time within the overall construction procedure for the arch bridge 1. In addition, the tendons 60 and compression members 70 can be placed on the floor 11 of the scaffolding 10, making construction easy. For the sake of explanation, the configuration of the scaffolding 10 other than the floor 11 is omitted in FIG. 6.

[0039] The above is an explanation of the procedure for constructing the arch member 3 between the piers 2, but the same procedure can also be used when constructing the arch member 3 between the piers 2 and abutments, or when constructing the arch member 3 between the abutments of a single-span arch bridge 1. The scaffolding 10 and other components are removed when they are no longer needed. In addition to the arch members 3, the arch bridge 1 also includes the construction of vertical members 4 and superstructure 5. The vertical members 4 and superstructure 5 can be constructed using normal methods, and so a description of them will be omitted here.

[0040] As described above, in this embodiment, instead of the general support, a scaffold (general scaffold) 10 is constructed, a curved melamine material 31 is installed on the scaffold 10, and concrete 32 is poured to bury the melamine material 31, thereby constructing the arch member 3. In this case, since the load during concrete pouring can be supported by the axial force of the melamine material 31, the scaffold 10 can be simplified compared to the general support, and the number of intermediate supports 20 can be reduced. In addition, since the melamine material 31 can be installed on the scaffold 10, a support for suspending the melamine material 31 in the air is not required. As a result, the arch member 3 can be constructed easily, and the construction period and construction costs can be reduced. In addition, the safety of construction is improved.

[0041] In this embodiment, when pouring concrete for the arch member 3, the bottom formwork 50 of the arch member 3 is supported by the melamine material 31, and the load during concrete pouring can be supported by the axial force of the melamine material 31 without being borne by the scaffolding 10. Also, the installation of the support beams 41 for arranging the bottom formwork 50 can be easily performed by installing the units 40 that are pre-assembled on the ground.

[0042] In this embodiment, the tension members 60 with tension introduced are spanned between the piers 2 supporting both ends of the arch member 3, and the compressive force of the tension members 60 resists the horizontal force generated in the piers 2 when pouring concrete for the arch member 3, thereby preventing cracks in the piers 2 due to horizontal forces. In addition, the compression members 70 spanned between the piers 2 make it possible to keep the spacing between the piers 2 constant against the compressive force.

[0043] However, the present invention is not limited to the above embodiment. For example, the shape and configuration of the arch bridge 1 are not limited to those described in Fig. 1, etc., as long as the arch member 3 is bridged between supports such as piers 2. Various configurations of the superstructure 5, etc. are possible. Furthermore, the specific configuration of the curved Melange material 31 is not limited to the above.

[0044] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to the above examples. It is clear that a person skilled in the art can come up with various modified or altered examples within the scope of the technical ideas disclosed in this application, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0045] 1: Arch bridge 2: Bridge pier 3: Arch member 10: Scaffolding 31: Melange wood 32: Concrete 40, U: Unit 41: Receiving column 42: Crossbeam 43: Temporary stand 50: Bottom formwork 60: Tensile material 70: Compression material

Claims

1. A construction method for an arch bridge, comprising the steps of: providing scaffolding at a position below the arch member of the arch bridge; A step of placing a curved Melange material on the scaffolding in accordance with the shape of the arch member; A step of constructing the arch member by pouring concrete so as to embed the Mellan material; 1. A method for constructing an arch bridge comprising the steps of:

2. 2. The method for constructing an arch bridge according to claim 1, characterized in that the bottom formwork of the arch member is supported from the melamine material when the concrete is poured.

3. The bottom formwork is placed on the support beam, A method for constructing an arch bridge as described in claim 2, characterized in that before installing the Mellan material, a unit integrating the support girder and a platform for positioning the support girder in accordance with the inclination of the arch member is installed on the scaffolding.

4. A tension member that introduces tension and a compression member that bears compression are spanned between piers that support both ends of the arch member, The compressive force of the tendon is used to resist the horizontal force generated in the pier when the concrete is poured, 2. The method for constructing an arch bridge according to claim 1, wherein the spacing between the piers is kept constant against the compressive force by the compression members.

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