Construction methods for emergency bridges

Abstract

To provide a method for constructing emergency bridges that can be done simply and quickly. [Solution] A method for constructing an emergency bridge by erecting bridge girders across both banks, comprising: a base frame laying step of laying a base frame, which is composed of long vertical steel frames in the direction of bridge girder erection and long horizontal steel frames in a direction perpendicular to the direction of erection, on at least one bank; a bridge girder assembly step of assembling a bridge girder by connecting multiple bridge girder pieces, which are composed of a plurality of main girder piece steel members that are long in the direction of erection and arranged parallel to the direction perpendicular to the direction of erection, and horizontal steel members that are long in the direction perpendicular to the direction of erection and stretched across the plurality of main girder piece steel members, in a stepped manner starting from the base frame with counterweights placed on the base frame; and a step of removing the counterweights after the completion of the bridge girder assembly step.

Description

[Technical Field]

[0001] This invention relates to a method for constructing emergency bridges. [Background technology]

[0002] Conventionally, in the event of disasters such as typhoons, torrential rains, and earthquakes, when general traffic is interrupted due to road collapses or bridge failures, and it is necessary to urgently secure transportation routes, emergency bridges are constructed to be erected at the affected locations to secure transportation routes. As a method for constructing such emergency bridges, the technology described in Patent Document 1 is known. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-259017 [Overview of the project] [Problems that the invention aims to solve]

[0004] In the case of emergency bridge construction like this, the urgency is particularly high, so it is essential that the construction can be done simply and quickly. This invention has been made in view of these circumstances, and aims to provide a method for constructing an emergency bridge that can be done simply and quickly. [Means for solving the problem]

[0005] The first method is, This method involves constructing a temporary bridge by erecting bridge girders across both banks. A base frame laying step is to lay a base frame, which is composed of long vertical steel members in the direction of the bridge girder erection and long horizontal steel members in a direction perpendicular to the direction of the bridge girder erection, on at least one bank. A bridge girder assembly process involves assembling a bridge girder by connecting multiple bridge girder pieces, each composed of a plurality of main girder pieces (long in the erection direction and parallel to the direction perpendicular to the erection direction) and transverse girder pieces (long in the direction perpendicular to the erection direction and spanning across the plurality of main girder pieces), in a stepped manner starting from the base frame, with a counterweight placed on the base frame. The process includes removing the counterweight after the completion of the bridge girder assembly process. This is a construction method for emergency bridges characterized by the following features.

[0006] The second means is the first means, In the aforementioned frame laying process, the frame is laid on one of the banks. The bridge girder erection process includes removing the counterweight, rotating the bridge girder around a predetermined pivot point, and landing the tip of the bridge girder on the opposite bank to erect the bridge girder. It is characterized by the following:

[0007] The third means is the second means, characterized in that each of the vertical frame steel members, horizontal frame steel members, main girder piece steel members, and horizontal girder steel members is made from a retaining wall main member.

[0008] The fourth means is the third means, Let n be the number of connected bridge girder pieces from the starting point (where n is a natural number), and let the main girder piece steel material and the cross girder steel material constituting the nth bridge girder piece from the starting point be the nth main girder retaining member and the nth cross girder retaining member, respectively. The first bridge girder piece comprises a first main girder retaining member whose base end is superimposed on the vertical frame steel members constituting the base frame, and a first cross girder retaining member placed on the first main girder retaining member. Each subsequent bridge girder piece comprises an nth transverse girder retaining member whose base end is superimposed on the (n-1)th main girder retaining member, and an nth transverse girder retaining member placed on top of the nth main girder retaining member. It is characterized by the following:

[0009] A fifth means is the fourth means, wherein the n-th cross-girder earth retaining main material of the third and subsequent bridge girder pieces is provided on the (n-2)-th main girder earth retaining main material and the (n-1)-th main girder earth retaining main material.

[0010] A sixth means is the fifth means, wherein the cross-girder steel material is an H-beam, and is disposed in an orientation with flanges facing upward and downward.

[0011] A seventh means is the sixth means, wherein the top surfaces of the upper flanges of the cross-girder steel materials in the plurality of bridge girder pieces are flush with each other.

[0012] An eighth means is the seventh means, wherein after the bridge girder erection step, lining plates are laid between the adjacent cross-girder steel materials to form a bridge deck.

[0013] A ninth means is the eighth means, wherein after the bridge girder erection step, a temporary guardrail based on the earth retaining main material is installed. Effects of the Invention

[0014] According to the present invention, since the bridge girder is assembled by connecting the bridge girder pieces in a stepped manner, the emergency bridge can be constructed simply and quickly. Brief Description of the Drawings

[0015] [Figure 1] It is a perspective view of the emergency bridge of the embodiment. [Figure 2] It is a front view for explaining the steps of the emergency bridge construction method. [Figure 3] It is a perspective view of the base frame. [Figure 4] It is a perspective view showing the connection structure between the base frame and the bridge girder and the connection structure of the bridge girder pieces. [Figure 5] It is a front view showing the mounting structure of the cross-girder earth retaining main material. [Figure 6] It is a perspective view of the inclined base. [Figure 7]This is a perspective view of a Z-shaped joint. [Figure 8] This is a perspective view of an L-shaped joint. [Figure 9] This is a perspective view of the pivot piece. [Figure 10] This is a perspective view of the corner piece. [Figure 11] This is a diagram showing the scaffolding installation structure. [Figure 12] This is a magnified perspective view of a portion of the completed emergency bridge. [Modes for carrying out the invention]

[0016] The construction method for an emergency bridge according to an embodiment of the present invention will be described below.

[0017] Figure 1 is a perspective view of the emergency bridge 100 according to the embodiment, and Figure 2 is a front view illustrating the construction process of the emergency bridge 100. The construction of this emergency bridge 100 is broadly divided into the following stages: the base frame installation stage A (Figure 2(A)), the bridge girder assembly stage B (Figure 2(B)), the bridge girder erection stage C (Figure 2(C)), and the bridge deck and guardrail installation stage D (Figure 2(D)).

[0018] (Base frame installation process A) The base frame installation process A is the process of installing the base frame 10 on one bank. Figure 3 is a perspective view of the base frame 10. The base frame 10 is constructed by connecting the main retaining members (H-beams) in a ladder-like manner. In other words, the base frame 10 is composed of two parallel vertical frames 11, 11 and several horizontal frames 12 stretched across the two vertical frames 11, 11. Each of the vertical frames 11 and horizontal frames 12 is made of earth retaining main members (H-beams). The base frame 10 is laid on one bank, and the two vertical frames 11, 11 extend toward the opposite bank.

[0019] The vertical frame 11 is constructed by stacking two main retaining members, and comprises a lower frame 11a and an upper frame 11b superimposed on the lower frame 11a. The lower frame 11a is constructed by connecting multiple main retaining members with flanges at the top and bottom in the longitudinal direction. Adjacent main retaining members in the lower frame 11a are connected by bolting the end plates of the main retaining members together. The main retaining members of the upper frame 11b are superimposed on the main retaining members of the lower frame 11a, with their flanges positioned vertically. Adjacent main retaining members in the upper frame 11b are positioned with gaps between them where the horizontal frames 12 fit. Then, the main retaining member of the upper frame 11b is connected to the main retaining member of the lower frame 11a by bolting its lower flange to the upper flange of the main retaining member of the lower frame 11a.

[0020] A horizontal frame 12 with its flange positioned horizontally is placed across the gap in the upper frame 11b. The main retaining member of this horizontal frame 12 is connected to the main retaining member of the upper frame 11b by bolting its flange to the end plate of the main retaining member of the upper frame 11b.

[0021] Furthermore, at the opposite bank end of the base frame 10, a portion of the retaining wall main member 13a of the lower frame 11a protrudes further towards the opposite bank than the end of the retaining wall main member 13b of the upper frame 11b.

[0022] The bolt connections between the main retaining members described above are made using bolt holes that are pre-formed in the main retaining members. The assembly of the base frame 10 may be done on-site, or all or part of it may be done in the factory.

[0023] (Bridge girder assembly process B) The bridge girder 20 is connected to the opposite bank end of the base frame 10. Figure 4 is a perspective view showing the connection structure between the base frame 10 and the bridge girder 20, and the connection structure of the bridge girder piece 20a. The bridge girder 20, with the counterweight CW placed on the base frame 10, is extended in a stepped manner upward toward the opposite bank, starting from the point where the cross girder main members (H-beams) 22 are installed on the main retaining members 13a.

[0024] The bridge girder 20 is composed of multiple retaining wall members (H-beams) of the same length. Except for the starting cross girder retaining main member 22, the bridge girder 20 has a structure in which multiple girder pieces 20a are connected toward the opposite bank, with some overlap between them, each piece consisting of two parallel main girder retaining main members 21, 21 with one cross girder retaining main member 22 spanning the middle of its length. Here, for the sake of explanation, let n be the number of bridge girder pieces 20a from the starting point (in this embodiment, n = 1 to 18), and the nth bridge girder piece 20a is referred to as bridge girder piece 20a n Also, bridge girder piece 20a n The main girder retaining member 21 and the cross girder retaining member 22 that make up the main girder retaining member 21 n and crossbeam main member 22 n Therefore, the bridge girder piece 20a is constructed as follows: In this embodiment, the main girder retaining members 21 and cross girder retaining members 22 are arranged so that their flanges are positioned vertically in the bridge girder 20. Furthermore, the cross girder retaining member 22 located at the starting position is referred to as the cross girder retaining member 220 to distinguish it from the other cross girder retaining members 22.

[0025] First, let's explain the main beam retaining member 220 that makes up the starting point. The main retaining beam member 220 that constitutes the starting point is installed on top of the main retaining beam member 13a of the lower frame 11a. Below this main retaining beam member 220, as shown in Figure 5, an inclined base 23 is installed with its upper surface having a predetermined upward slope toward the opposite bank. Figure 6 is a perspective view of the base 23. The base 23 is bolted to the main retaining member 13a. This bolting can be done on-site or in advance at the factory.

[0026] The horizontal beam retaining member 220 is connected to the middle of the length of the retaining member 13a using a Z-shaped joint 24. Figure 7 is a perspective view of the Z-shaped joint 24. Specifically, the crossbeam retaining wall main member 220 is connected to the retaining wall main member 13a by a Z-shaped joint 24, where one leaf is bolted to the upper flange of the retaining wall main member 13a at the base end of the retaining wall main member 13a, and the other leaf is fastened together with the lower flange of the crossbeam retaining wall main member 220 to the base 23.

[0027] Then, adjustment pieces 25a, 25a are bolted to the upper surface of the main girder retaining member 220 on both sides in the bridge width direction. This bolting can be done on-site or in advance at the factory.

[0028] Next, we will describe the bridge girder piece 20a1 that is connected to the base frame 10. Returning to Figure 4, on the opposite bank side of the crossbeam retaining member 220, the base end of the main girder retaining member 211 is superimposed on the retaining member 13a. The tip end of the main girder retaining member 211 protrudes further towards the opposite bank than the end of the retaining member 13a. The main girder retaining member 211 is connected to the retaining member 13a by bolting its lower flange to the upper flange of the retaining member 13a. As shown in Figure 5, the crossbeam retaining wall main member 220 and the main girder retaining wall main member 211 are connected by an L-shaped joint 26. Figure 8 is a perspective view of the L-shaped joint 26. Specifically, the crossbeam retaining wall main member 220 is connected to the main girder retaining wall main member 211 by bolting one leaf of the L-shaped joint 26 to the end plate of the main girder retaining wall main member 211, and by fastening the other leaf together with the lower flange of the crossbeam retaining wall main member 220 to the base 23. The fastening of the other leaf and the lower flange of the crossbeam retaining wall main member 220 to the base 23 may be done on-site or in advance at the factory. Furthermore, a pivot piece (earth retaining component) 27a, which has been pre-fixed to the abutment, is connected to the tip of the main girder earth retaining member 211 by bolting using existing bolt holes. Figure 9 is a perspective view of the pivot piece 27a. This bolting can be done on-site or in advance at the factory.

[0029] A crossbeam retaining member 221 is connected to the middle of the main girder retaining member 211 in the longitudinal direction. On the opposite bank side of the crossbeam retaining member 221, the base end of the main girder retaining member 212 is superimposed on the main girder retaining member 211. The tip end of the main girder retaining member 212 protrudes further towards the opposite bank than the end of the main girder retaining member 211. The connection between the main girder retaining member 211 and the main girder retaining member 212 is made by bolting the opposing flanges together. Further, the connection between the cross-beam earth retaining main member 221 and the main girder earth retaining main member 211 or the main girder earth retaining main member 212 is performed using the pedestal 23, the Z-shaped joint 24 and the L-shaped joint 26, similarly to the case of the connection of the cross-beam earth retaining main member 220 described above. In this case, the connection between the cross-beam earth retaining main member 221 and the main girder earth retaining main member 211 may be performed on site, or may be performed in advance at a factory. Further, a corner piece 28 is provided at the lower stepped portion between the main girder earth retaining main member 211 and the main girder earth retaining main member 212, and the end piece of the main girder earth retaining main member 211 and the lower flange of the main girder earth retaining main member 212 are connected to the corner piece 28 by bolted connection. In this case, the bolted connection between the corner piece 28 and any one of the end piece of the main girder earth retaining main member 211 and the lower flange of the main girder earth retaining main member 212 may be performed in advance at a factory. FIG. 10 is a perspective view of the corner piece 28.

[0030] Similarly, the main girder earth retaining main member 21 n In the longitudinal middle portion (2≦n≦18), the cross-beam earth retaining main member 22 n is connected. The cross-beam earth retaining main member 22 n On the opposite bank side of, on the main girder earth retaining main member 21 n Above, except for the case where n=18, the main girder earth retaining main member 21 n+1 The base end side of is provided in an overlapping manner. The main girder earth retaining main member 21 n+1 The distal end side of the main girder earth retaining main member 21 n protrudes to the opposite bank side beyond the end portion of. The main girder earth retaining main member 21 n and the main girder earth retaining main member 21 n+1 The connection between them is achieved by bolting the flanges to each other. Further, the cross-beam earth retaining main member 22 n and the main girder earth retaining main member 21 n or the main girder earth retaining main member 21 n+1 The connection is performed using the pedestal 23, the Z-shaped joint 24 and the L-shaped joint 26, similarly to the case of the connection of the cross-beam earth retaining main member 221 described above. In this case, the cross-beam earth retaining main member 22 n and the main girder earth retaining main member 21 n The connection between them may be performed on site, or may be performed in advance at a factory. Further, the main girder earth retaining main member 21 nand main beam retaining wall main member 21 n+1 The corner piece (earth retaining component) 28, which is provided in the lower step portion, is bolted together using existing bolt holes, thereby connecting the main girder earth retaining main member 21 n The end piece, and the main girder retaining member 21 n+1 The lower flange is connected. Note: Bridge girder piece 20a n Crossbeam main member 22 n This is the main beam retaining member 21 n―2 and main beam retaining member 21 n-1 It is located on top of [something].

[0031] In this manner, a bridge girder 20 of a predetermined length is assembled. In this case, the components are transported using a rougher crane or the like. Note: Main girder retaining wall main member 21 n As shown in Figure 11, a scaffolding 29 is provided on the exposed underside of the bridge girder 20 for (2≦n), with the framework consisting of a support beam 29a and a support column 29b, via clamps. This scaffolding 29 is also stepped. In Figure 2, this scaffolding 29 is represented by a thick line. This scaffolding 29 is connected to the main girder retaining wall main member 21 n It is preferable to install it in advance for (2≦n). Furthermore, the upper surfaces of all horizontal beam retaining members 22 are provided to be flush with the surface.

[0032] (Bridge girder erection process C) The counterweight CW is removed using an uplift release device (not shown), and the base frame 10 and bridge girder 20 are slowly rotated around the pivot piece (support point) 27a. Then, the main girder retaining member 21 16 The lower flange is connected to the pivot piece 27b, which has been pre-fixed to the abutment, by bolt connection. At this time, the scaffolding 29 at the landing point is removed. Additionally, if necessary, a portion of the base frame 10 may be removed after the bridge girder 20 has been erected. In this case, the uplift is opened using a rougher crane or similar device.

[0033] (Bridge deck installation process and guardrail installation process) Figure 12 is an enlarged perspective view of a portion of the completed emergency bridge 100. In this bridge deck installation process, FRP (Fiber Reinforced Plastics) covering plates 30 are placed between adjacent crossbeam retaining members 22 and bolted together. Here, four FRP covering plates 30 are bolted together in the bridge width direction, with the length direction of the FRP covering plates 30 being in the bridge length direction. Subsequently, temporary guardrails 32 are installed on both sides in the bridge width direction, using earth-retaining main members (H-beams) 31 with their flanges oriented horizontally as foundations.

[0034] Finally, slopes 33a and 33b are formed at both ends of the bridge girder in the direction of the bridge length. This completes the emergency bridge 100. In this case, the materials are transported using rougher cranes or similar equipment.

[0035] (Effects of the embodiment) The construction method of the emergency bridge 100 in this embodiment provides the following advantages. In other words, according to the construction method of the emergency bridge 100 of this embodiment, the bridge girder 20 can be erected simply by extending the bridge girder piece 20a in a stepped manner from one bank and rotating it around the support point 27a, thus enabling the construction of the emergency bridge 100 easily and quickly. Furthermore, even if there is a difference in height between the two banks, the emergency bridge 100 can be constructed easily and quickly. Furthermore, since it primarily uses shoring materials and components, and bolts are joined using existing bolt holes, procurement is easy and processing time is reduced, which in turn makes construction simple and quick.

[0036] Variant form Although embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the invention.

[0037] For example, in the above embodiment, a temporary guardrail 32 was installed as a traffic safety device, but instead of the temporary guardrail 32, or in addition to the temporary guardrail 32, traffic safety devices such as handrails may be installed.

[0038] Furthermore, although the above embodiment mainly uses retaining wall main members and retaining wall components, other steel materials can be used. For example, as a member to which a pivot piece is attached, a steel material in which two rod-shaped steel materials are integrated in a stepped manner can be used.

[0039] Furthermore, in the above embodiment, a base frame was laid on one bank and the girder pieces were connected to it in a stepped manner. However, base frames may be laid on both banks, and the girder pieces may be connected to each of them in a stepped manner, with the meeting points of the girder pieces being connected at the end of the girder erection process.

[0040] Furthermore, in the above embodiment, the base 23 had a low top surface, making it difficult to insert bolts, nuts, and tools into the inside of the base 23. However, the top surface may be made higher to make it easier to insert bolts, nuts, and tools into the inside of the base 23. In this case, the base 23 can be directly bolted to the main girder retaining member and the cross girder retaining member without using the Z-shaped joint 24 and the L-shaped joint 26 for fixing. [Explanation of Symbols]

[0041] 10 base frame 11 Vertical frame 11a Bottom frame 11b Upper frame 12 Horizontal frame 13a,13b Yamadome main material 20 Bridge girders 20a Bridge girder piece 21 Main girder retaining material 22 Cross girder retaining main material (H steel) 23 Pedestal 24 Z-type joint 25a Adjustment piece 26 L-shaped joint 27a, 27b Pivot Pieces 28 Corner Pieces 29 Scaffolding 30 FRP lining board 31 Yamadome main material 32 Temporary guardrails 33a, 33b Slope 100 Emergency bridges

Claims

1. This method involves constructing a temporary bridge by erecting bridge girders across both banks. A base frame laying step is to lay a base frame, which is composed of long vertical steel members in the direction of the bridge girder erection and long horizontal steel members in a direction perpendicular to the direction of the bridge girder erection, on at least one bank. A bridge girder assembly process involves assembling a bridge girder by connecting multiple bridge girder pieces, each composed of a plurality of main girder pieces (long in the erection direction and parallel to the direction perpendicular to the erection direction) and transverse girder pieces (long in the direction perpendicular to the erection direction and spanning across the plurality of main girder pieces), in a stepped manner starting from the base frame, with a counterweight placed on the base frame. The process includes removing the counterweight after the completion of the bridge girder assembly process. A method for constructing an emergency bridge characterized by the following features.

2. In the aforementioned frame laying process, the frame is laid on one of the banks. The bridge girder erection process includes removing the counterweight, rotating the bridge girder around a predetermined pivot point, and landing the tip of the bridge girder on the opposite bank to erect the bridge girder. The method for constructing an emergency bridge as described in feature 1.

3. The method for constructing an emergency bridge according to claim 2, characterized in that each of the vertical frame steel members, horizontal frame steel members, main girder piece steel members, and horizontal girder steel members is composed of a retaining wall main member.

4. Let n be the number of connected bridge girder pieces from the starting point (where n is a natural number), and let the main girder piece steel material and the cross girder steel material constituting the nth bridge girder piece from the starting point be the nth main girder retaining member and the nth cross girder retaining member, respectively. The first bridge girder piece is composed of a first main girder retaining member whose base end is superimposed on the vertical frame steel members that constitute the base frame, and a first cross girder retaining member that is placed on the first main girder retaining member. Each subsequent bridge girder piece comprises an nth transverse girder retaining member whose base end is superimposed on the (n-1)th main girder retaining member, and an nth transverse girder retaining member placed on top of the nth main girder retaining member. The method for constructing an emergency bridge as described in feature 3.

5. The method for constructing an emergency bridge according to claim 4, characterized in that the nth transverse girder retaining main member of the third and subsequent bridge girder pieces is provided on the (n-2) main girder retaining main member and the (n-1) main girder retaining main member.

6. The method for constructing an emergency bridge according to claim 5, characterized in that the transverse beam steel material is an H-beam and is installed in a orientation such that the flanges are at the top and bottom.

7. The method for constructing an emergency bridge according to claim 6, characterized in that the upper surfaces of the upper flanges of the transverse girder steel members in the multiple bridge girder pieces are flush with the surface.

8. The method for constructing an emergency bridge according to claim 7, characterized in that, after the bridge girder erection process, a covering plate is placed between adjacent cross girders to form a bridge deck.

9. The method for constructing an emergency bridge according to claim 8, characterized in that, after the bridge girder erection process, a temporary guardrail is installed with the main retaining material as its foundation.

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