Bridge replacement method and bridge construction method

Abstract

To provide a bridge rebuilding method and a construction method that can simply and accurately adjust the weight balance on piers when rebuilding or newly constructing a superstructure by half-section construction.SOLUTION: In a bridge rebuilding method where a superstructure (girders 12, slabs 11) which is supported by a T-shaped pier 13 that consists of a single vertical column part 14 and a column head part 15 extending perpendicularly to the bridge axis is rebuilt in a half-section by half-section sequence, a beam 17 is placed near the column head part 15, with an extension part 17a of the beam 17 protruding in the extension direction of the column head part 15 on the removal side, and a counterweight 19 is placed on the extension part 17a, and the weight balance on the pier is adjusted by changing the distance from the bridge axis to the center of gravity of the counterweight 19 according to the progress of the superstructure removal work, etc.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for replacing the superstructure (floor slab, girder, etc.) of an existing bridge (especially a road bridge), and a method for installing the superstructure in a newly constructed bridge. In particular, it relates to a bridge replacement method and an installation method for a bridge supported by bridge piers of a shape in which excessive stress may be generated in the column due to uneven loads, such as T-shaped or inverted L-shaped bridge piers.

Background Art

[0002] When replacing the superstructure (floor slab, girder, etc.) of a road bridge, when it is impossible to secure a detour around it and it is difficult to close the entire surface of the road for traffic, in some cases, a method of replacing the superstructure in half cross-sections in turn while releasing traffic on one side of the road surface (half cross-section construction) may be carried out.

[0003] Specifically, when carrying out half cross-section construction on the road bridge 10 as shown in Fig. 6(1), while leaving the left floor slab 11A and girder 12A in place and maintaining a state where vehicles and pedestrians can pass on the left half, the right floor slab 11B and girder 12B are removed, new girders and new floor slabs are installed, and after restoring the right half to a passable state, the left floor slab 11A and girder 12A are removed, etc.

[0004] However, when carrying out half cross-section construction on the road bridge 10 supported by a T-shaped bridge pier 13 (a bridge pier composed of a single vertical column part 14 and a column head part 15 extending in a direction perpendicular to the bridge axis) as shown in Fig. 6(1), if either the left or right floor slab 11 and girder 12 are removed without any countermeasures, the left-right weight balance will be disrupted, and there is a risk that the acting stress of the bridge pier 13 near the column part 14 will exceed the allowable value. Therefore, as shown in Fig. 6(2), when removing one side (floor slab 11B, girder 12B) of the superstructure, it is effective to install a vent 16 under the opposite column head part 15 to directly support the bridge pier 13, but depending on the ground conditions and the relationship with other structures, it may not be possible to install the vent 16.

[0005] In such cases, a method has been proposed to maintain the weight balance on the pier 13 by fixing beam members 17 near both sides of the column head 15 (the front side 15a of the column head 15 shown in Figure 6(2), and the opposite side not shown) so that the column head 15 extends outward (in the direction perpendicular to the bridge axis) on the side to be removed (the right side in the example of Figure 6(2)), with a portion of these (extension portion 17a) protruding in the direction of extension of the column head 15 (in the direction perpendicular to the bridge axis), and then loading a counterweight 19 (for example, a solid heavy object such as a steel plate) on this extension portion 17a. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-188454 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] When constructing a half-section of a bridge, if a counterweight 19 is loaded to maintain the weight balance on the pier 13, it is necessary to adjust the amount of the counterweight 19 to match the progress of the removal or installation of the deck slab 11, etc., in order to manage the load so that the weight balance always stays within an appropriate range. However, loading and unloading operations take a considerable amount of time, and may require interrupting the removal work each time, which hinders smooth construction and can lead to delays in the construction period.

[0008] The present invention aims to solve the problems of the prior art and provides a bridge replacement method and construction method that allows for easy and accurate adjustment of the weight balance on the bridge pier when replacing or constructing the superstructure by half-section construction. [Means for solving the problem]

[0009] The bridge replacement method according to the present invention is a method of sequentially replacing the superstructure, which is supported by T-shaped or inverted L-shaped bridge piers composed of a single vertical column and a column head extending perpendicular to the bridge axis, in half-section at a time. The method is characterized by placing a beam member near the column head, with the extension of the beam member protruding in the direction of extension of the column head on the removal side, placing a counterweight on the extension, and adjusting the weight balance on the bridge pier by changing the distance from the bridge axis to the center of gravity of the counterweight in accordance with the progress of the superstructure removal or installation work.

[0010] In this replacement method, it is preferable to place the base on which the counterweight is mounted on the extension so that it can move along the longitudinal direction of the beam, connect the base to a drive mechanism (such as a hydraulic jack) fixed to the bridge axis, and adjust the weight balance on the bridge pier by changing the distance from the bridge axis to the center of gravity of the counterweight by operating the drive mechanism in accordance with the progress of the removal or installation work of the superstructure, thereby moving the base and counterweight along the longitudinal direction of the beam. In this case, it is preferable to place the base on the extension with rollers or other rollers on the bottom, or with a bottom made of a material with a low coefficient of friction.

[0011] Furthermore, by connecting the extension of the beam member to the base of the beam member fixed near the column head using a hinge that rotates around a horizontal axis or a hinge that rotates around a vertical axis, the extension member can be configured to rotate upward or horizontally. A base on which a counterweight is placed is fixed on top of the extension member, and a drive mechanism fixed to the bridge axis is connected to the base or extension member. By operating the drive mechanism to rotate the extension member in accordance with the progress of the superstructure removal or installation work, the distance from the bridge axis to the center of gravity of the counterweight can be changed, thereby adjusting the weight balance on the bridge pier.

[0012] Furthermore, by holding the beam member in a position near the column head so that it can move along the longitudinal direction of the beam member, fixing the base on which the counterweight is placed on the extension, and connecting the drive means to the base or beam member, the drive means can be operated in accordance with the progress of the removal or installation work of the superstructure to move the base, counterweight, and beam member along the longitudinal direction, thereby changing the distance from the bridge axis to the center of gravity of the counterweight and adjusting the weight balance on the bridge pier.

[0013] Alternatively, a pool can be installed on the base, and water pumped up into the pool can be stored and used as a counterweight.

[0014] The bridge erection method according to the present invention is a method of sequentially installing a superstructure supported by a T-shaped or inverted L-shaped pier, which is composed of a single vertical column and a column head extending perpendicular to the bridge axis, in half sections at a time. The method is characterized by placing a beam member near the column head, with the extension of the beam member protruding in the direction of extension of the column head, placing a counterweight on the extension, and adjusting the weight balance on the pier by changing the distance from the bridge axis to the center of gravity of the counterweight as the superstructure installation work progresses. [Effects of the Invention]

[0015] According to the bridge replacement method and erection method of the present invention, when performing half-section construction, the weight balance on the bridge pier can be easily and accurately adjusted, and the loading and unloading of counterweights can be omitted or significantly reduced. As a result, the removal of the old deck and the installation of the new deck can be carried out smoothly, and delays in the construction period can be suitably avoided. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is an explanatory diagram of a bridge replacement method according to the first embodiment of the present invention, showing the side view of the bridge pier 13 and the cross-section of the deck slab 11. [Figure 2]Figure 2 is a perspective view of a base 18 and the like that can be used in the bridge replacement method according to the first embodiment of the present invention. [Figure 3] Figure 3 is an explanatory diagram of a bridge replacement method according to a second embodiment of the present invention, showing the side view of the bridge pier 13 and the cross-section of the deck slab 11. [Figure 4] Figure 4 is an explanatory diagram of a bridge replacement method according to a third embodiment of the present invention, and is a plan view of the column head 15 of the bridge pier 13, etc. [Figure 5] Figure 5 is an explanatory diagram of a bridge replacement method according to the fourth embodiment of the present invention, showing the side view of the bridge pier 13 and the cross-section of the deck slab 11. [Figure 6] Figure 6 is an explanatory diagram of the conventional construction method (a method for replacing the superstructure of a road bridge using half-section construction), and shows the side view of the bridge pier 13, etc., and the cross-section of the deck slab 11, etc. [Modes for carrying out the invention]

[0017] The "bridge replacement method" and "bridge erection method" according to the present invention will be described below with reference to the attached drawings. Figure 1 is an explanatory diagram of the bridge replacement method according to the first embodiment of the present invention. The replacement method of this embodiment can be applied when performing half-section construction on a road bridge 10, as shown in Figure 1, or more specifically, a road bridge 10 in which the superstructure (girders 12, 12A, 12B, and deck slabs 11, 11A, 11B) is supported by T-shaped piers 13 (piers composed of a single vertical column 14 and a column head 15 extending perpendicular to the bridge axis). Figure 1 shows an example in which removal work is performed on the right-hand deck slab 11B and girder 12B, indicated by the dashed lines, of the deck slab 11 and girder 12.

[0018] In the method for replacing a bridge of the present embodiment, before removing the floor slab 11B and the girder 12B, first, a beam member 17 (such as a steel material with an I-shaped or H-shaped cross-section) is fixed to the column head 15. More specifically, the beam members 17 are arranged and fixed one by one at positions near both side surfaces of the column head 15 (the front side surface 15a of the column head 15 shown in FIG. 1 and the opposite side surface not shown), and a part thereof (extension part 17a) protrudes in the extension direction (direction perpendicular to the bridge axis) of the column head 15 on the removal side.

[0019] A base 18 is arranged on the extension part 17a. Further, a counterweight 19 is placed on the base 18 and fixed to the base 18. Furthermore, a hydraulic jack 21 (driving means) is fixed to the bridge axis side of the base 18 (a position between the center of the base 18 and the column head 15), and the tip of its telescopic rod is connected to the base 18. In the present embodiment, the base 18 used has rollers or rollers arranged at the lower part 24, or the bottom part (the part in contact with the beam member 17) is formed of a material with a small friction coefficient (for example, polytetrafluoroethylene). Therefore, by operating the connected hydraulic jack 21 (extending and retracting the rod), the base 18 can be moved in the longitudinal direction (direction perpendicular to the bridge axis) of the beam member 17 on the extension part 17a of the beam member 17.

[0020] In addition, as shown in FIG. 2, it is preferable that the lower part 24 of the base 18 has side guides 26 that press the left and right flange edges 25 of the upper flange of the extension part 17a from the outside and engage the lower part 24 with the extension part 17a. In this case, the extension part 17a itself can be used as a track, and the base 18 and the counterweight 19 can be safely moved while preventing them from falling off from the position on the extension part 17a.

[0021] Also, in FIG. 2, two lower parts 24 are connected, but the number of lower parts 24 is not limited, and they can be appropriately added (or removed) according to the load, size, or shape of the counterweight 19 placed on the base 18, etc., and can be connected in the longitudinal direction (the longitudinal direction of the extension part 17a) through the connecting part 27.

[0022] Then, as the removal of the deck slab 11B and girder 12B progresses, and the installation of the new deck slab, etc., the hydraulic jack 21 can be operated as appropriate to move the base 18 and counterweight 19 along the longitudinal direction of the beam member 17, thereby easily adjusting the weight balance on the pier 13. More specifically, as the load of the deck slab 11B and girder 12B supported on the pier 13 gradually decreases as the removal work progresses, the base 18 and counterweight 19 can be moved away from the bridge axis (to the right in the example of Figure 1) to maintain a position where the left and right balance is maintained, and during the installation of the new deck slab, etc., they can be moved towards the bridge axis (to the left in the example of Figure 1), thereby easily and accurately adjusting the weight balance on the pier 13.

[0023] Therefore, in removal work such as the removal of the deck slab 11B, the loading and unloading of the counterweight 19 can be omitted (or significantly reduced), allowing the removal work to be carried out smoothly (continuously without interruption by loading work, etc.), and effectively avoiding delays in the construction period.

[0024] Figure 3 is an explanatory diagram of a bridge replacement method according to the second embodiment of the present invention. In the first embodiment, the base 18 is configured to be movable on the extension 17a, but in this embodiment, the base 18 is fixed to the extension 17a. Furthermore, the extension 17a of the beam member 17 (the portion that protrudes in the extension direction of the column head 15) is connected to the base 17b (the portion fixed near the side surface 15a of the column head 15) by a hinge 22 that rotates around a horizontal axis, and the extension 17a is configured to be able to rotate upward starting from this hinge 22.

[0025] Therefore, when the hydraulic jack 21 (with a telescopic rod connected to the base 18) is operated from the state shown by the solid line in Figure 3 (the state in which the extension 17a extends horizontally) to pull the base 18 toward the bridge axis, the extension 17a, base 18, and counterweight 19 rotate upward (for example, to the position shown by the dashed line in Figure 3), and their center of gravity moves closer to the bridge axis. Also, when the hydraulic jack 21 is operated from the position shown by the dashed line in Figure 3 to extend the rod, the extension 17a, etc. rotate toward their original state (the position shown by the solid line in Figure 3), and their center of gravity moves away from the bridge axis.

[0026] By appropriately operating the hydraulic jacks 21 in accordance with the progress of the removal of the old deck and the installation of the new deck, the center of gravity of the counterweights 19 (distance from the bridge axis) can be changed, thereby adjusting the weight balance on the bridge piers 13.

[0027] Figure 4 is an explanatory diagram of a bridge replacement method according to the third embodiment of the present invention. In the second embodiment, the extension 17a is connected by a hinge 22 that rotates around a horizontal axis and is configured to rotate upward, but in this embodiment, the extension 17a is connected to the base 17b by a hinge 22 that rotates around a vertical axis and is configured to rotate horizontally starting from this hinge 22.

[0028] Therefore, when the hydraulic jack 21 (with a telescopic rod connected to the base 18) is operated from the state shown by the solid line in Figure 4 (where the extension 17a is located on the extension side of the column head 15) to pull the base 18 toward the bridge axis, the extension 17a, base 18, and counterweight 19 rotate horizontally (for example, to the position shown by the dashed line in Figure 4), and their centers of gravity move closer to the bridge axis. Also, when the hydraulic jack 21 is operated from the position shown by the dashed line in Figure 4 to extend the rod, the extension 17a, etc., rotate toward their original state (the position shown by the solid line in Figure 4), and their centers of gravity move away from the bridge axis.

[0029] By appropriately operating the hydraulic jacks 21 in accordance with the progress of the removal of the old deck and the installation of the new deck, the center of gravity of the counterweights 19 (distance from the bridge axis) can be changed, thereby adjusting the weight balance on the bridge piers 13.

[0030] Figure 5 is an explanatory diagram of a bridge replacement method according to a fourth embodiment of the present invention. In the above embodiment, the base 17b of the beam member 17 is fixed near the side surface 15a of the column head 15, but in this embodiment, the beam member 17 is held by a holder 28 near the side surface 15a of the column head 15 so as to be movable in the longitudinal direction (direction perpendicular to the bridge axis, left and right direction in Figure 5).

[0031] Then, from the state shown by the solid line in Figure 5, when the hydraulic jack 21 (fixed on the column head 15 and with an extension rod connected to the extension 17a) is operated and pulled toward the bridge axis, the beam member 17, base 18, and counterweight 19 move in the longitudinal direction of the beam member 17 (for example, to the position shown by the dashed line in Figure 5), and their center of gravity moves closer to the bridge axis. Furthermore, when the hydraulic jack 21 is operated and the rod is extended from the position shown by the dashed line in Figure 5, the beam member 17, etc. move toward their original state (the position shown by the solid line in Figure 5), and their center of gravity moves away from the bridge axis.

[0032] By appropriately operating the hydraulic jacks 21 in accordance with the progress of the removal of the old deck and the installation of the new deck, the center of gravity of the counterweights 19 (distance from the bridge axis) can be changed, thereby adjusting the weight balance on the bridge piers 13.

[0033] Furthermore, a holder 28 for holding the beam member 17 near the side surface 15a of the column head 15 may be adopted, which has a feeding mechanism consisting of a roller and a hydraulic motor (drive device) that rotates the roller. By operating the drive device of this holder 28 instead of the hydraulic jack 21, the beam member 17 and counterweight 19 may be moved in the longitudinal direction.

[0034] Furthermore, the beam member 17 may be a multi-stage telescopic sheath pipe structure similar to a crane boom, and the tip of the beam member 17 and the counterweight 19 placed on the tip may be configured to move in the longitudinal direction using a mechanism (drive device, etc.) similar to that of a crane boom.

[0035] In the first to fourth embodiments described above, a solid heavy object such as a steel plate is used as the counterweight 19. However, if water can be supplied from a river or other water source, a pool (water storage tank) can be installed on the base 18, and water pumped up by a submersible pump can be stored in the pool and used as a counterweight.

[0036] Furthermore, in the above embodiments 1 to 4, a hydraulic jack 21 or a hydraulic motor for rotating rollers is used as a driving means for moving or rotating the beam member 17, extension 17a, etc., but other driving means, such as a winch (hoisting device) for winding up or unwinding wires or chains, or various other actuators can also be used.

[0037] Furthermore, while the first to fourth embodiments described above show examples of applying the present invention to a "bridge replacement method" in which the superstructure of an existing road bridge is replaced by half-section construction, the present invention can also be applied to a "bridge erection method" in which the superstructure is divided into half-sections and installed sequentially when constructing a new bridge. In this case, the extension of the beam material is positioned to protrude on the opposite side from the side in which one side of the superstructure is installed first. [Explanation of Symbols]

[0038] 10: Road bridge, 11,11A,11B: Floor slab, 12, 12A, 12B: Digits, 13: Bridge piers, 14: Pillar part, 15: Column head, 15a: side, 16: Bent, 17: Beam material, 17a: extension, 17b: base, 18: Bass, 19: Counterweight, 21: Hydraulic jack, 22: Hinge 24: Bottom, 25: Edge, 26: Lateral guide, 27: Connecting part, 28: Holder,

Claims

1. A method of sequentially replacing the superstructure, which is supported by T-shaped or inverted L-shaped bridge piers composed of a single vertical column and a column head extending perpendicular to the bridge axis, in half-sections at a time. A beam is positioned near the column head, with the extension of the beam protruding in the direction of extension of the column head on the side to be removed. A counterweight is placed on top of the extension. A bridge replacement method characterized by adjusting the weight balance on the bridge piers by changing the distance from the bridge axis to the center of gravity of the counterweight in accordance with the progress of the removal or installation of the superstructure.

2. The base on which the counterweight is placed is positioned on the extension so that it can move along the longitudinal direction of the beam. The drive mechanism is connected to the base, A bridge replacement method according to claim 1, characterized in that, in accordance with the progress of the removal or installation of the superstructure, the driving means is operated to move the base and counterweight along the longitudinal direction of the beam member, thereby changing the distance from the bridge axis to the center of gravity of the counterweight and adjusting the weight balance on the bridge pier.

3. The bridge replacement method according to claim 2, characterized in that a base is placed on the extension, the base having rollers or other supports arranged at the bottom, or the base being formed of a material with a low coefficient of friction.

4. The extension of the beam is connected to the base of the beam, which is fixed near the column head, by a hinge that rotates around a horizontal axis or a hinge that rotates around a vertical axis, thereby configuring the extension to be able to rotate upward or horizontally. The base on which the counterweight is placed is fixed onto the extension, The drive mechanism is connected to the base or extension, A bridge replacement method according to claim 1, characterized in that, in accordance with the progress of the removal or installation of the superstructure, the driving means is operated to rotate the extension, thereby changing the distance from the bridge axis to the center of gravity of the counterweight and adjusting the weight balance on the bridge pier.

5. The beam is held by a holder near the column head so that it can move along the longitudinal direction of the beam. The base on which the counterweight is placed is fixed onto the extension, The drive mechanism is connected to the base or beam member, A bridge replacement method according to claim 1, characterized in that, in accordance with the progress of the removal or installation of the superstructure, the driving means is operated to move the base, counterweight, and beam along the longitudinal direction, thereby changing the distance from the bridge axis to the center of gravity of the counterweight and adjusting the weight balance on the bridge pier.

6. The bridge replacement method according to claim 5, characterized in that a holder for holding beam members is used, which has a feeding mechanism consisting of a roller and a drive device for rotating the roller, and the beam members are moved in the longitudinal direction by operating the drive device of this holder.

7. The bridge replacement method according to claim 5, characterized in that a multi-stage telescopic sheath pipe structure is used as the beam material, and the tip of the beam material on which the counterweight is placed is moved in the longitudinal direction by operating a drive device.

8. A method of sequentially installing a superstructure, half at a time, supported by a T-shaped or inverted L-shaped pier, which is composed of a single vertical column and a column head extending perpendicular to the bridge axis, A beam is positioned near the column head, with the extension of the beam protruding in the direction of extension of the column head. A counterweight is placed on top of the extension. A bridge erection method characterized by adjusting the weight balance on the bridge piers by changing the distance from the bridge axis to the center of gravity of the counterweight in accordance with the progress of the superstructure installation work.

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