Set-off technique

Abstract

To provide a set-off technique capable of continuing the movement of a bridge girder regardless of the presence or absence of a step on a sliding surface.SOLUTION: A set-off method is a side-moving method for moving a bridge girder from a trestle to an abutment by sliding the bridge girder on a sliding surface in the abutment and the trestle which are adjacent to each other so as to form the sliding surface whose top surfaces are substantially flush with each other, the method comprises: a first installation step of providing the bridge girder with a first bearing that supports the bridge girder between the first bearing and the sliding surface; a second installation step of providing the bridge girder with a second bearing that is vertically expandable and contractible at a position in front of or behind the first bearing along a moving direction of the bridge girder and forms a gap between the second bearing and the sliding surface when the second bearing is contracted; a first moving step of moving the bridge girder; an extending step of extending the second bearing after the first moving step to cause the second bearing to support the bridge girder and form a gap between the first bearing and the sliding surface; and a second moving step of moving the bridge girder in a state where the gap is formed between the first bearing and the frame.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for transferring a bridge girder from a bridge platform to an abutment. [Background technology]

[0002] One method of installing a bridge girder on an existing abutment is the horizontal installation method. One example of this method is to build a platform next to the abutment, manufacture the bridge girder on the platform, and then slide the manufactured bridge girder from the platform onto the abutment. In this horizontal installation method, the top surfaces of the platform and the abutment are made to be continuous and roughly flush. These continuous and roughly flush top surfaces form the sliding surface along which the bridge girder slides.

[0003] Bridge girders are equipped with bearings that support the girders between them and the sliding surface. When the bridge girders are moved, the bottom of the bearings comes into contact with the sliding surface. In order for the bridge girders to move smoothly, the bottom of the bearings must be made of a material that has a low coefficient of friction with the sliding surface. For example, a Teflon (registered trademark) plate is installed on the bottom of the bearings.

[0004] Steel plates are laid on the platform and abutment, and these steel plates become the top surfaces of the platform and abutment, forming the slideway mentioned above. Stainless steel plates, for example, are used for the steel plates. It is difficult to prepare steel plates large enough to cover the entire slideway, so the slideway is formed by arranging multiple steel plates side by side. Adjustments are made to prevent unevenness at the joints between adjacent steel plates, but eliminating unevenness with high precision requires a great deal of effort. Even if flatness is ensured when the steel plates are laid, unevenness may suddenly occur at the joints between the steel plates due to the load applied to the steel plates during the horizontal construction method.

[0005] If the support hits a step while the bridge girder is moving, the Teflon plate attached to the bottom of the support will be scraped off, allowing the support to overcome the step and the bridge girder to continue moving. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 59-195908 Summary of the Invention [Problem to be solved by the invention]

[0007] However, with conventional technology, when the step is large or when multiple steps are crossed, the Teflon plate can become severely damaged, increasing the coefficient of friction between the bearing and the sliding surface and making it difficult for the bridge girder to continue its lateral movement. Furthermore, in order to minimize damage to the Teflon plate and ensure the bridge girder continues its lateral movement, it requires a great deal of effort to eliminate the step and monitor for any sudden occurrence of step changes during construction.

[0008] The present invention aims to provide a method for siding that allows the bridge girder to continue moving regardless of whether there is a step on the sliding surface. [Means for solving the problem]

[0009] The cross-mounting method of the present invention is a cross-mounting method in which a bridge girder is moved from an abutment to an abutment by sliding it on a sliding surface, where the abutment and a platform are adjacent to each other so that they form a sliding surface where the top surfaces of both are approximately flush with each other. The method comprises: a first installation step in which a first support is provided on the bridge girder to support the bridge girder between it and the sliding surface; a second installation step in which a second support is provided on the bridge girder in a position in front of or behind the first support along the direction of movement of the bridge girder, the second support being expandable and contractible up and down so that a gap is formed between it and the sliding surface when contracted; a first movement step in which the bridge girder is moved; an extension step in which, after the first movement step, the second bearing is extended to support the bridge girder on the second bearing, thereby forming a gap between the first bearing and the sliding surface; and a second movement step in which the bridge girder is moved with a gap formed between the first bearing and the platform. [Effects of the Invention]

[0010] According to the present invention, it is possible to obtain a cross-cutting method that allows the bridge girder to continue moving regardless of whether there is a step on the sliding surface. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing the schematic configuration of an existing bridge abutment. [Figure 2] FIG. 2 is a flowchart showing the steps of the interception method according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing the steps of the intercepting method according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing the steps of the intercepting method according to the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing the steps of the intercepting method according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing the steps of the intercepting method according to the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing the steps of the intercepting method according to the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing the steps of the intercepting method according to the first embodiment. [Figure 9] Figure 9 is a cross-sectional view of the bridge girder constructed on the trestle. [Figure 10] FIG. 10 is a diagram showing a modified example of the bridge girder. DETAILED DESCRIPTION OF THE INVENTION

[0012] A stealing method according to an embodiment of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the embodiment described below.

[0013] [Embodiment 1] <How to steal> Figure 1 is a cross-sectional view showing the general configuration of an existing abutment. An existing abutment 1 is installed as shown in Figure 1. The abutment 1 is a structure erected on the ground. The abutment 1 supports a bridge girder 2. The bridge girder 2 supported by the abutment 1 has a bridge main girder 21 and rails (not shown) installed on it, and trains pass over the bridge girder 2. In some cases, construction work is carried out to remove the existing bridge girder 2 and install a new bridge girder 2 on the abutment. One method for installing a new bridge girder 2 is the lateral removal method. The steps for the lateral removal method, which are explained below, are the steps for the lateral removal method.

[0014] In the horizontal removal method, the existing bridge girder 2 installed on the abutment 1 is removed before a new bridge girder 2 is installed on the abutment 1, but the explanation of the procedure for removing the existing bridge girder 2 will be omitted.

[0015] Fig. 2 is a flowchart showing the steps of the intercepting method according to embodiment 1. Figs. 3 to 8 are cross-sectional views showing the steps of the intercepting method according to embodiment 1.

[0016] First, as shown in FIG. 3, a platform 3 is constructed next to an abutment 1 (step S1). Next, a plurality of steel plates 4 are laid on the abutment 1 and the platform 3 (step S2). The steel plates 4 laid on the abutment 1 and the platform 3 form the top surfaces 5 of the abutment 1 and the platform 3. The steel plates 4 are made of, for example, stainless steel. The top surfaces 5 become the sliding surfaces along which the bridge girder 2 slides. Note that the steel plates 4 are laid on the platform 3 in step S2, and the laying of the steel plates 4 on the abutment 1 may be performed after step S3, which will be described later. Furthermore, adjustments are made at the joints 41 between the plurality of steel plates 4 to eliminate any steps so that they form approximately the same surface.

[0017] Next, the bridge girder 2 is erected on the cradle 3 (step S3, first installation step). Here, the configuration of the bridge girder 2 erected on the cradle 3 will be described. Fig. 9 is a cross-sectional view of the bridge girder erected on the cradle.

[0018] A plurality of first bearings 6 are provided on the underside of the bridge girder 2. Each first bearing 6 includes a rubber bearing 61 and a bottom plate 62. The rubber bearings 61 support the bridge girder 2 between themselves and the top surface 5 of the frame 3. When the bridge girder 2 is installed on the abutment 1, the rubber bearings 61 absorb vibrations and the like of the bridge girder 2.

[0019] The bottom plate 62 is provided on the underside of the rubber bearing 61. The bottom plate 62 is the part that comes into contact with the top surface 5 of the platform 3 and the abutment 1. The bottom plate 62 is preferably made of a material that has a small coefficient of friction with the top surface 5, such as Teflon.

[0020] A side block 7 is provided adjacent to the first support 6. The side block 7 is provided on the underside of the bridge girder 2. A gap is provided between the lower end of the side block 7 and the top surface 5 of the base 3 and the abutment 1.

[0021] The side blocks 7 are installed on both sides of the rubber bearing 61. After the bridge girder 2 is installed on the abutment 1, the rubber bearing 61 needs to deform to follow the girder movement during operation. However, if the rubber bearing 61 deforms when the bridge girder 2 is pulled or pushed into the traction device during the process of moving from the pedestal 3 to the abutment 1, it will hinder the movement of the bridge girder 2, so measures to prevent deformation are required. In Figure 9, the traction direction when the bridge girder 2 moves is indicated by arrow X. When the bridge girder 2 is moved from the pedestal 3 to the abutment 1, the side blocks 7 abut against the rubber bearing 61 to prevent deformation of the rubber bearing 61. After the bridge girder 2 is installed on the abutment 1, the side blocks 7 are removed.

[0022] The load of the bridge girder 2 is concentrated in the area where the rubber bearings 61 and side blocks 7 are provided on the underside of the bridge girder 2, so a reinforcing section 8 is formed to reinforce the bridge girder 2. The reinforcing section 8 is configured, for example, by installing more buried reinforcement than in other areas or by burying steel plates.

[0023] A second bearing 9 is provided on the underside of the bridge girder 2, to the side of the first bearing 6. The second bearing 9 is fixed to the underside of the bridge girder 2 using, for example, bolts. The second bearing 9 is provided at a position forward or backward along the direction of travel when the bridge girder 2 is moved. The second bearing 9 is a jack that can be extended and retracted vertically using hydraulics or the like. When contracted, a gap is formed between the second bearing 9 and the top surface 5. In the initial state when fixed to the underside of the bridge girder 2, the second bearing 9 is contracted. Furthermore, when extended, the second bearing 9 has a length that protrudes downward below the rubber bearing 61. A bottom plate 92 is provided on the bottom surface of the second bearing 9. A material with a low coefficient of friction with the top surface 5 is used for the bottom plate 92. For example, the bottom plate 92 is formed of Teflon or hardened steel plate. The second bearing 9 may be configured by combining multiple jacks into a unit.

[0024] The part of the underside of the bridge girder 2 where the second bearing 9 is provided may be subject to a concentrated load of the bridge girder 2, so a reinforcing part 10 is formed to reinforce the bridge girder 2. The reinforcing part 10 is configured, for example, by installing more buried reinforcement than in other areas or by burying steel plates.

[0025] In this way, step S3 of constructing the bridge girder 2 includes a step of fixing the second bearing 9 (second installation step).

[0026] Returning to the explanation of the procedure for the cross-cutting method, as shown in Figures 2 and 4, the bridge girder 2 is moved from the top of the pedestal 3 toward the top of the abutment 1 (step S4, first movement step). The movement of the bridge girder 2 in step S4 is performed by towing the bridge girder 2 using a traction jack 12 installed at the end of the pedestal 3 and a towing jack 11 installed at the end of the abutment 1, causing the bridge girder 2 to slide across the top surface 5. At this time, the bottom plate 62 of the first support 6 slides while abutting against the top surface 5. In addition, the weight of the bridge girder 2 is applied to the bottom plate 62. Therefore, it is preferable that the coefficient of friction between the bottom plate 62 and the steel plate 4 constituting the top surface 5 is small so that the bridge girder 2 can be moved with less force. Therefore, as described above, for example, Teflon is used as the material for the bottom plate 62, and stainless steel is used as the material for the steel plate 4.

[0027] As the bridge girder 2 continues to move, the first bearing 6 reaches the joint 41 of the steel plates 4. The top surface 5 formed by arranging multiple steel plates 4 is adjusted to form a roughly flush surface, but a step may remain at the joint 41 between the steel plates 4. As the bottom plate 62 in contact with the step at the joint 41 is scraped away, the first bearing 6 can overcome the joint 41 while remaining in contact with the top surface 5. However, considering that the bridge girder 2 should continue to move even if the bottom plate 62 is scraped away, the material for the bottom plate 62 is essentially limited to Teflon, and there is little freedom of choice. Because the material for the bottom plate 62 is limited, the performance of the towing jack 11 and the traction jack 12 is also determined, making it difficult to consider slimming down the structure.

[0028] On the other hand, in the first embodiment, the bridge girder 2 is moved so that the first bearing 6 does not come into contact with the joint 41. Specifically, as shown in FIG. 5, when the second bearing 9 is located in a position avoiding the area above the joint 41, the second bearing 9 is extended so that its bottom surface protrudes downward from the bottom plate 62 of the first bearing 6. As a result, the bridge girder 2 is jacked up by the second bearing 9, and a gap is formed between the first bearing and the top surface 5 (step S5, extension step). Next, with the bridge girder 2 in a jacked-up state, the bridge girder 2 is moved toward the top of the abutment 1 (step S6, second movement step). In step S6, once the bridge girder 2 has moved to a position where the first bearing 6 avoids the area above the joint 41 of the steel plate 4 as shown in FIG. 6, the second bearing 9 is retracted as shown in FIG. 7. As a result, the bridge girder 2 is jacked down by the second bearings 9, and the bottom plate 62 comes into contact with the top surface 5, and the bridge girder 2 is supported by the first bearings 6 (step S7, reduction step).

[0029] Next, the bridge girder 2 supported by the first bearing 6 is further moved toward the top of the frame 3 (step S8, third movement step). In the process of moving the bridge girder 2, steps S5 to S8 are repeated every time the first bearing 6 approaches the joint 41, so that the bridge girder 2 can be moved to the installation position on the abutment 1 shown in FIG. 8 without the first bearing 6 coming into contact with the joint 41.

[0030] Figure 10 is a diagram showing a modified example of a bridge girder. As shown in Figure 10, a bracket 13 may be provided on the side of the bridge girder 2, and the second bearing 9 may be fixed to the underside of the bracket 13. In this case, there is no need to crawl under the bridge girder 2 to fix the second bearing 9, improving workability. In Figure 10, the arrow Y indicates the traction direction when the bridge girder 2 moves.

[0031] <Summary of effects> The above-described cross-mounting method is a cross-mounting method for moving a bridge girder 2 from abutment 3 to abutment 1 by sliding it on the sliding surface (top surface 5) of an adjacent abutment 1 and a platform 3, where the top surfaces 5 of both are approximately flush with each other and form a sliding surface. The method comprises: a first installation step of providing a first bearing 6 on the bridge girder 2 to support the bridge girder 2 between it and the sliding surface; a second installation step of providing a second bearing 9 on the bridge girder 2 in a position in front of or behind the first bearing 6 along the movement direction of the bridge girder 2, the second bearing 9 being expandable and contractible up and down so that a gap is formed between it and the sliding surface when contracted; a first movement step of moving the bridge girder 2; an extension step of extending the second bearing 9 after the first movement step to support the bridge girder 2 on the second bearing 9 and form a gap between the first bearing 6 and the sliding surface; and a second movement step of moving the bridge girder 2 with a gap formed between the first bearing 6 and the platform 3.

[0032] This makes it possible to move the bridge girder 2 from the platform 3 to the abutment 1 without the first bearing 6 getting caught on the step formed at the joint 41 of the steel plate 4. Therefore, there is no need to consider the resistance when the first bearing 6 gets over the joint 41, which makes it possible to reduce the size of the towing jack 11 and the traction jack 12 used and to suppress construction costs.

[0033] Furthermore, when the first bearing 6 is made to overcome the step at the joint 41, the bridge girder may not be able to continue moving if the damage to the bottom plate 62 becomes too great and the coefficient of friction increases. On the other hand, with the cross-cutting method of the first embodiment, the bridge girder 2 can be moved without the first bearing 6 climbing over the joint 41, thereby reducing the risk that the bridge girder 2 will not be able to continue moving.

[0034] Furthermore, if the first support 6 is to climb over the joint 41, the bottom plate 62 needs to be made of a material that can be scraped away by the step at the joint 41. Teflon, which is given as an example of the material for the bottom plate 62, can satisfy both the requirement that it can be easily scraped away by the step at the joint 41 and the requirement that it have a small coefficient of friction with the top surface 5. On the other hand, if scraping away by the step is not a consideration, the bottom plate 62 can be made of a material that has a smaller coefficient of friction with the top surface 5 without considering scraping away by the step. For example, the bottom plate 62 may be made of a hardened steel plate, or the bottom plate 62 may be made of another bottom friction material.

[0035] The cross-cutting method may further include a reduction step of reducing the second bearing 9 after the second moving step to make the first bearing 6 support the bridge girder 2 .

[0036] For example, by shrinking the second bearing 9 and having the first bearing 6 support the bridge girder 2, a gap can be formed between the bottom plate 92 of the second bearing 9 and the top surface 5. This makes it possible to move the bridge girder 2 without having the second bearing climb over the joint 41 of the steel plate 4.

[0037] The cross-cutting method may further include a third moving step of moving the bridge girder 2 after the reduction step. This allows the bridge girder 2 to be moved to an installation position on the abutment 1.

[0038] Furthermore, after the bridge girder 2 is installed on the abutment 1, the second bearing 9 may be removed or left in place. If the second bearing 9 is left in place rather than removed, the bridge girder 2 can be jacked up even after installation. For example, if work such as replacing the rubber bearing 61 of the first bearing 9 becomes necessary, the bridge girder 2 can be jacked up using the second bearing 9 to perform the replacement work, thereby shortening the construction period and reducing construction costs. [Explanation of symbols]

[0039] 1. Abutment 2 Bridge girders 21 Bridge main girder 3 Mounting stand 4 steel plate 41 Seam 5 Top 6 First support 61 Rubber bearing 62 Bottom plate 7 Side Block 8 Reinforcement 9 Second Support 91 Bottom plate 10 Reinforcement 11 Towing jack 12. Reluctant Jack 13 Bracket

Claims

1. A method for moving a bridge girder from an abutment to an abutment by sliding it on a sliding surface where the top surfaces of the abutment and the abutment are adjacent to each other and form a sliding surface that is approximately flush with each other, comprising: a first installation step of providing a first support on the bridge girder to support the bridge girder between the first support and the slide surface; a second installation process in which a second support is provided on the bridge girder at a position in front of or behind the first support along the movement direction of the bridge girder, the second support being vertically expandable and contractible so that a gap is formed between the second support and the sliding surface when contracted; a first moving step of moving the bridge girder; an extension step of extending the second bearing after the first movement step to cause the second bearing to support the bridge girder, thereby forming a gap between the first bearing and the sliding surface; a second moving step of moving the bridge girder in a state where a gap is formed between the first support and the frame; A stealing method comprising:

2. The method according to claim 1, further comprising a step of reducing the second bearing after the second moving step to allow the first bearing to support the bridge girder.

3. The method of claim 2, further comprising a third moving step of moving the bridge girder after the reducing step.

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