Pier construction method and bridge construction method

Abstract

To provide a pier construction method that enables bridge construction to continue even during river flood season.SOLUTION: A pier construction method constructs a pier 3 to be used in a construction of a bridge crossing a river 9. The pier construction method includes a pier substructure construction step of constructing a pier substructure 30 at a height equal to or higher than the planned high water level (HWL) of the river 9 and equal to or lower than a height equal to that of an existing substructure 10, at positions spaced apart in the flow direction of the river 9 and spaced apart approximately the same as that of the existing substructure 10 of the bridge in the bridge axis direction, and a pier erection step of constructing the pier 3 by installing an erection girder 33 on the pier substructure 30 along the bridge axis direction.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a pier, a pier construction method, a bridge reconstruction method, and a bridge construction method. [Background technology]

[0002] In order to erect a bridge over a river or the like, a work pier may be constructed near the water surface of the river or the like during seasons other than flood season. A known method for constructing such a pier is a pier erection method in which a unit structure equipped with a substructure is connected to a superstructure, and support piles are driven through the unit structure (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6007307 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the pier was built to match the water level during non-flood seasons, if flood season occurred during the bridge construction period, the pier had to be temporarily removed to avoid significant obstruction to the flow of water during floods. As a result, construction of the bridge was delayed during flood seasons, which caused the problem of longer construction periods.

[0005] In order to solve the above-mentioned problems, the present invention provides a pier, a pier construction method, a bridge reconstruction method, and a bridge construction method that allow bridge construction to continue even during river flood season. [Means for solving the problem]

[0006] The pier construction method of the present invention is a method for constructing a pier to be used in constructing a bridge across a river, and includes a bridge substructure construction process and a pier erection process. In the pier substructure construction process, the pier substructure is constructed, and in the pier erection process, the erection girder is sent out from one side to the other in the bridge axis direction and installed on the pier substructure.

[0007] The pier construction method of the present invention can also be used as a method for constructing a pier substructure so that the height is equal to or higher than the planned high water level of a river.

[0008] The pier construction method of the present invention can also be a method of installing erection girders on three or more pier substructures so as to form continuous girders.

[0009] The pier construction method of the present invention is a pier construction method for constructing a pier to be used in the construction of a bridge across a river, and is a method that includes a bridge substructure construction process and a pier erection process. In the pier substructure construction process, the pier substructure is constructed so that it is at a height equal to or higher than the planned high water level of the river, and in the pier erection process, an erection girder is installed on the pier substructure. In the pier erection process, an erection girder is installed on three or more pier substructures to form a continuous girder.

[0010] The bridge construction method of the present invention is a method for constructing a new bridge that crosses a river using a pier, and is a method that includes a pier substructure construction process, a pier erection process, a new substructure construction process, and a new superstructure construction process. In the pier substructure construction process, the pier substructure is constructed, and in the pier erection process, the erection girder that is sent out from one side to the other in the bridge axis direction is installed on the pier substructure. In the new substructure construction process, the new substructure is constructed using the pier, and in the new superstructure construction process, the new superstructure is constructed on the new substructure using the pier. The bridge construction method of the present invention can also be a method in which a new superstructure is installed on an erection girder, the new superstructure is moved laterally from the erection girder toward the new substructure, and the new superstructure is then installed on the new substructure.

[0011] The bridge construction method of the present invention can also be used to continue using a pier even during the river's flood season without having to remove it. Effect of the Invention

[0012] According to the present invention, construction of a bridge can be continued even during flood season of a river. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a side view showing an existing bridge to be reconstructed by a bridge reconstruction method according to a first embodiment of the present invention. [Diagram 2] 1 is a flowchart showing a bridge reconstruction method according to a first embodiment (and a second embodiment) of the present invention. [Diagram 3] FIG. 2 is a cross-sectional view illustrating a steel pipe sheet pile pre-installation step and a pier pile pre-installation step of the bridge reconstruction method according to the first embodiment of the present invention. [Figure 4] FIG. 2 is a plan view illustrating a steel pipe sheet pile pre-installation process and a pier pile pre-installation process of the bridge reconstruction method according to the first embodiment of the present invention. [Diagram 5] FIG. 2 is a side view illustrating the existing superstructure removal process in the bridge reconstruction method according to the first embodiment of the present invention. [Figure 6] FIG. 2 is a cross-sectional view illustrating the existing superstructure removal process and the pier substructure construction process of the bridge reconstruction method according to the first embodiment of the present invention. [Figure 7] FIG. 2 is a cross-sectional view illustrating a pier erection process of the bridge reconstruction method according to the first embodiment of the present invention. [Figure 8] FIG. 2 is a cross-sectional view illustrating the existing substructure removal process (driving permanent steel pipe sheet piles) in the bridge reconstruction method according to the first embodiment of the present invention. [Figure 9]FIG. 2 is a cross-sectional view illustrating an existing substructure removal step (removal of the existing substructure) in the bridge reconstruction method according to the first embodiment of the present invention. [Figure 10] FIG. 2 is a cross-sectional view illustrating a new substructure construction process of the bridge reconstruction method according to the first embodiment of the present invention. [Figure 11] 1 is a cross-sectional view illustrating a new superstructure construction process and a pier removal process of a bridge reconstruction method according to a first embodiment of the present invention. FIG. [Figure 12] FIG. 11 is a cross-sectional view illustrating the new superstructure construction process of the bridge reconstruction method according to the second embodiment of the present invention. [Figure 13] 1 is a flowchart showing a bridge construction method according to a first embodiment of the present invention. [Figure 14] FIG. 2 is a cross-sectional view illustrating a new substructure construction step and a new superstructure construction step of the bridge construction method according to the first embodiment of the present invention. [Figure 15] FIG. 11 is a side view illustrating a bridge reconstruction method and a new superstructure construction process of the bridge reconstruction method according to a modified example of the first embodiment of the present invention. [Figure 16] 10 is a flowchart showing a bridge reconstruction method according to a third embodiment of the present invention. [Figure 17] FIG. 11 is a step diagram illustrating a bridge reconstruction method according to a third embodiment of the present invention. [Figure 18] FIG. 11 is a plan view showing a temporary road formed by a temporary superstructure and a connecting section in a bridge reconstruction method according to a third embodiment of the present invention. [Figure 19] FIG. 11 is a step diagram illustrating a rotary slide method in a bridge reconstruction method according to a third embodiment of the present invention. [Figure 20] 5 is a flowchart showing a bridge reconstruction method according to a modified example of the first embodiment (and the second embodiment) of the present invention. [Figure 21] 10 is a flowchart showing a bridge reconstruction method according to another modified example of the first embodiment (and the second embodiment) of the present invention. [Figure 22] 13 is a flowchart showing a bridge reconstruction method according to another modified example of the second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. In this specification, the direction parallel to the bridge (the direction in which the bridge crosses (is erected)) will be referred to as the "bridge axis direction," and the direction along the flow of the river 9 will be referred to as the "flowing water direction." In the drawings, "U" indicates "up," "Lo" indicates "down," "X" indicates the bridge axis direction, and "Y" indicates the flowing water direction. In this specification, terms indicating directions and positions are used, but these terms are used for convenience of explanation and do not limit the technical scope of the present invention.

[0015] [First embodiment: Bridge reconstruction method] A bridge reconstruction method according to the first embodiment will be described with reference to Figs. 1 to 11. Fig. 1 is a side view showing an existing bridge 1 to be reconstructed by the bridge reconstruction method. Fig. 2 is a flowchart showing the bridge reconstruction method. Fig. 3 is a cross-sectional view explaining the steel pipe sheet pile pre-casting step S1 and the pier pile pre-casting step S2 of the bridge reconstruction method. Fig. 4 is a plan view explaining the steel pipe sheet pile pre-casting step S1 and the pier pile pre-casting step S2 of the bridge reconstruction method. Fig. 5 is a side view explaining the existing superstructure removal step S3 of the bridge reconstruction method. Fig. 6 is a cross-sectional view explaining the existing superstructure removal step S3 and the pier substructure construction step S4 of the bridge reconstruction method. Fig. 7 is a cross-sectional view explaining the pier erection step S5 of the bridge reconstruction method. Fig. 8 is a cross-sectional view explaining the existing substructure removal step S6 (casting of permanent steel pipe sheet piles 40) of the bridge reconstruction method. Fig. 9 is a cross-sectional view explaining the existing subwork removal step S6 (removal of the existing subwork 10) in the bridge reconstruction method. Fig. 10 is a cross-sectional view explaining the new subwork construction step S7 in the bridge reconstruction method. Fig. 11 is a cross-sectional view explaining the new superwork construction step S8 and the pier removal step S9 in the bridge reconstruction method.

[0016] The bridge reconstruction method is a method for reconstructing a bridge that crosses a river 9 using a pier 3. Specifically, the bridge reconstruction method is a method (construction method) of removing an existing bridge 1 (see FIG. 1) and replacing it with a new bridge 2. Here, the method of replacing the existing bridge 2 includes a method of replacing it at a different location from the existing bridge 1 when viewed from above, and a method of replacing it at approximately the same location. In the former case, in order to connect roads and railroad tracks in a linear manner, it is necessary to change the horizontal alignment of the roads, etc., and to acquire land accordingly. In the latter case, it is generally considered to take time (construction period) because it is necessary to remove the existing bridge 1, build a new substructure 20, and then replace it with the new bridge 2. The bridge reconstruction method described below is an example of the latter method. In the bridge reconstruction method, the entire existing bridge 1 (total length in the bridge axis direction) may be replaced, or only a part of the existing bridge 1 (a part of the section in the bridge axis direction) may be replaced. In addition, in this specification, the existing bridge 1 and the new bridge 2 are collectively referred to simply as "bridges."

[0017] As shown in FIG. 1, the existing bridge 1 has three existing substructures 10 (two abutments and one pier) and an existing superstructure 13 that is spanned across the three existing substructures 10. The existing substructure 10 has an existing caisson 11 buried in the ground and an existing structure 12 erected on the existing caisson 11. The existing superstructure 13 has a deck (not shown) that supports loads such as vehicles, a plurality of main girders 14 that transmit the load received by the deck to the existing substructure 10, a cross beam 15 that connects the plurality of main girders 14 to distribute the load, and a truss 16 that extends upward from the plurality of main girders 14. The bridge is spanned across a river 9 at an angle to the flowing water direction and the direction perpendicular to the flowing water direction when viewed from above (see FIG. 4). In other words, the bridge crosses the river 9 diagonally. As will be described in more detail later, the new bridge 2, like the existing bridge 1, has three new substructures 20 and a new superstructure 23.

[0018] The bridge type is not limited to a truss, and may be, for example, an arch, a box girder, or a plate girder. The material used for the bridge may be, for example, steel or concrete. The bridge may be, for example, a road bridge, a railway bridge, or a combined bridge of these. In this specification, the existing substructure 10 and the new substructure 20 are collectively referred to as "substructure", and the existing superstructure 13 and the new superstructure 23 are collectively referred to as "superstructure". The term "superstructure" refers to a structure including a deck and girders 14, 15, etc., and the term "substructure" refers to a structure such as an abutment or pier that supports the superstructure. In this specification, a bridge having three substructures is exemplified, but the present invention is not limited to this, and two or more substructures may be provided. In this specification, for convenience of explanation, the description will be mainly focused on one substructure (pier).

[0019] As shown in FIG. 2, the bridge reconstruction method includes a steel pipe sheet pile preliminary installation process S1, a pier pile preliminary installation process S2, an existing superstructure removal process S3, a pier substructure construction process S4, a pier erection process S5, an existing substructure removal process S6, a new substructure construction process S7, a new superstructure construction process S8, and a pier removal process S9.

[0020] <Steel pipe sheet pile pre-installation process, pier pile pre-installation process> As shown in Fig. 3 and Fig. 4, in a steel pipe sheet pile advance installation process S1, heavy equipment 90 such as a crawler crane or a pile driver is placed on the deck of the existing bridge 1, and multiple (e.g., eight as shown by solid lines in Fig. 4) permanent steel pipe sheet piles 40 are installed on both sides of the existing substructure 10 of the existing bridge 1 in the flowing water direction using the heavy equipment 90 (pile driver). In a pier pile advance installation process S2, multiple (e.g., eight in Fig. 4) pier piles 31 are installed on one side (upstream side) of the existing substructure 10 in the flowing water direction using the heavy equipment 90 (pile driver). The multiple pier piles 31 are arranged in a lattice pattern in positions (areas) that are approximately aligned in the flowing water direction of the existing substructure 10, with two rows of four piles aligned in the flowing water direction aligned in the bridge axis direction (see Fig. 4).

[0021] <Existing superstructure removal process> Next, in the existing superstructure removal process S3, the erection girder 33 is installed on the existing bridge 1 (existing superstructure 13) (S3-1). Specifically, the deck of the existing bridge 1 is removed to expose the main girder 14, cross girder 15, etc. Next, as shown in Figs. 5 and 6, a plurality of launching equipment 91 is placed on a plurality of cross girders 15 (existing superstructure 13) arranged in parallel in the bridge axis direction, and the jacked-up erection girder 33 is placed on the launching equipment 91. The launching equipment 91 applies a driving force to the erection girder 33, and launches the erection girder 33 from one side to the other in the bridge axis direction. The erection girder 33 is formed to have a length equal to or greater than the span length of two adjacent existing substructures 10. Therefore, the erection girder 33 is erected between the two adjacent existing substructures 10. A hand-stretched girder 33A extending toward the other side of the bridge axis direction is fixed to the other end of the erection girder 33 in the bridge axis direction (the tip in the sending direction). The erection girder 33 including the hand-stretched girder 33A is formed to a length at least equal to two spans of the bridge and to a length necessary for removing the existing substructure or constructing a new substructure, and functions as a continuous girder erected over the river 9. The erection girder 33 excluding the hand-stretched girder 33A may be formed to a length at least equal to two spans of the bridge and to a length necessary for removing the existing substructure or constructing a new substructure. However, in the case of a bridge with only one span, the erection girder 33 including the hand-stretched girder 33A has a length of at least one span of the bridge. The span means the distance between the substructure 10 supporting the superstructure and the substructure 10. For example, the bridge in FIG. 1 has two spans.

[0022] In the existing superstructure removal process S3, the existing superstructure 13 of the existing bridge 1 is removed using the erection girder 33 (S3-2). Specifically, first, a rail system 92 is installed on the erection girder 33 along the bridge axis direction, and a traveler crane 93 (jib crane) and a transport cart 94 are installed on the rail system 92 so that they can run on it. Next, the main girder 14 and the truss 16 (existing superstructure 13) are hoisted onto the erection girder 33 by multiple hoisting equipment 95 (see FIG. 5), and then cut (divided) into multiple pieces in the bridge axis direction. The existing superstructure 13 divided into multiple pieces is loaded onto the transport cart 94 by the traveler crane 93, and carried out of the bridge by the transport cart 94. In this manner, the existing superstructure 13 is removed.

[0023] <Pier substructure construction process> Next, in the pier substructure construction process S4, the pier substructure 30 of the pier 3 to be used in the construction of a bridge across the river 9 is constructed. Specifically, as shown in Fig. 6, surrounding members 32A are attached so as to surround the upper parts of the multiple pier piles 31 cast in the pier pile preliminary casting process S2 (see Fig. 4), and a pier support base 32B is installed on the upper ends of the multiple pier piles 31. The multiple pier piles 31 are connected by the surrounding members 32A and the pier support base 32B to construct the pier substructure 30. The surrounding members 32A and the pier support base 32B are attached to the multiple pier piles 31 using a traveling crane 93 or a crane (not shown) mounted on a barge, or the like.

[0024] The pier subworks 30 is constructed at a distance from the existing subworks 10 on one side of the water flow direction and at a distance approximately the same as that of the existing subworks 10 in the bridge axis direction (see also FIG. 4). The pier subworks 30 is provided so as to be aligned with the existing subworks 10 in the water flow direction. The pier subworks 30 is constructed at a height equal to or higher than the planned high water level (hereinafter also referred to as HWL (High Water Level)) of the river 9. The pier subworks 30 is constructed at a height approximately the same as that of the existing subworks 10. In other words, the pier subworks 30 is formed at approximately the same height as the existing subworks 10, and the upper ends of the pier subworks 30 and the existing subworks 10 are approximately aligned. In addition, the pier substructure 30 is spaced apart from the existing substructure 10 in the direction of flowing water means that the pier substructure 30 is separated from the existing substructure 10 by a space (gap), and the space is set to an extent that makes construction (work) easy, for example, within the reach of the jib (arm) of the traveler crane 93 (for example, 5 m or less). In addition, the pier substructure 30 is constructed at a position spaced apart from the existing substructure 10 in the bridge axis direction, not only meaning that the pier substructure 30 matches the span length of the existing substructure 10, but also meaning that a slight shift in the bridge axis direction is allowed depending on the conditions at the site. In addition, the pier substructure 30 is at the same height as the existing substructure 10, not only meaning that the upper ends of the pier substructure 30 and the existing substructure 10 match, but also meaning that an error (step) is allowed that does not hinder the lateral movement of the erection girder 33 to the pier substructure 30 in the pier erection process S5 described later. In addition, the design high water level of River 9 refers to the water level when the design high water flow flows down the river channel cross section after the river has been improved. Here, the design high water flow is the basic flow rate when constructing a river channel, and refers to the flow rate that flows through the river channel obtained as a result of rationally allocating the basic high water to the river channel and various flood control facilities. In other words, it is the flow rate obtained by subtracting the flood control volume of various flood control facilities from the basic high water flow rate. Note that this design high water flow appears during the flood season of River 9.

[0025] <Pier construction process> Next, in the pier erection process S5, the erection girder 33 is installed on the pier substructure 30 along the bridge axis direction to construct the pier 3. Specifically, as shown in Fig. 7, a temporary beam 41 extending toward the pier substructure 30 is attached to the upper part of the existing substructure 10. The travel crane 93 and transport cart 94 installed on the erection girder 33 are removed, and the rail equipment 92 is left behind without being removed, but the rail equipment 92 may be removed and reconstructed in a later process. Also, equipment for mounting a crawler crane can be assembled on the erection girder 33 as a movable work platform.

[0026] Next, a plurality of lateral transfer equipment 96 are arranged on the temporary beams 41 and the pier substructure 30 (pier support base 32B) at intervals in the flowing water direction, and the jacked-up erection girder 33 is placed on the lateral transfer equipment 96. The lateral transfer equipment 96 includes, for example, a rail clamp jack and an endless feed device. The lateral transfer equipment 96 (endless feed device, etc.) moves the erection girder 33 used for removing the existing superstructure 13 laterally from the existing bridge 1 to the pier substructure 30 in the flowing water direction (see the white arrow in FIG. 7). The erection girder 33 is installed on the pier substructure 30 along the bridge axis direction, thereby constructing the pier 3. After the pier 3 is constructed, a traveler crane 93, a pile driver, etc. are installed on the rail equipment 92, and the temporary beams 41 and the lateral transfer equipment 96 are removed (see FIG. 8). The above-mentioned pier pile preliminary driving process S2, pier substructure construction process S4, and pier erection process S5 are an example of a pier construction method for constructing the pier 3.

[0027] <Existing substructure removal process> In the existing substructure removal process S6, a part of the existing substructure 10 is removed using the pier 3. Specifically, as shown in Figs. 4 and 8, prior to removing a part of the existing substructure 10, a pile driver is used to drive a plurality of permanent steel pipe sheet piles 40 on both sides of the existing substructure 10 in the bridge axis direction (S6-1). That is, in the existing substructure removal process S6, a plurality of permanent steel pipe sheet piles 40 (e.g., 18 piles shown by two-dot chain lines in Fig. 4) are driven into positions where the permanent steel pipe sheet piles 40 could not be driven in the steel pipe sheet pile advance driving process S1. The plurality of permanent steel pipe sheet piles 40 (e.g., a total of 28 piles in Fig. 4) are driven to surround the periphery of the existing substructure 10 to form a water cutoff wall 40A. The water cutoff wall 40A has a water cutoff (closure) function to prevent water from flowing into the periphery of the existing substructure 10 and also has an earth retaining function to resist earth pressure. The water blocking wall 40A also functions as a foundation structure for the newly constructed substructure 20.

[0028] 9, a work platform 42 is installed around the multiple permanent steel pipe sheet piles 40 using a travel crane 93 or the like, and a part of the existing substructure 10 is removed using heavy machinery 97 arranged on the work platform 42 (S6-2). In detail, the existing structure 12 and the upper part of the existing caisson 11 are removed.

[0029] <New substructure construction process> In the new substructure construction process S7, a new substructure 20 is constructed in place of the removed existing substructure 10 using the pier 3. Specifically, as shown in Fig. 10, the new substructure 20 has a new footing 21 and a new structure 22, and the new footing 21 is constructed in the portion from which the upper part of the existing caisson 11 was removed, and the new structure 22 is erected (constructed) on the new footing 21. Next, the work platform 42 is removed, and a plurality of permanent steel pipe sheet piles 40 are cut near the bottom of the river 9.

[0030] <New superstructure construction process> As shown in Fig. 11, in the new superstructure construction process S8, the new superstructure 23 is installed on the new substructure 20 along the bridge axis direction. Specifically, a launching facility 91 (not shown in Fig. 11 (see Fig. 5)) is installed on the new substructure 20, and the new superstructure 23 constructed on the ground is placed on the launching facility 91. The launching facility 91 launches the new superstructure 23 from one side to the other in the bridge axis direction. The new superstructure 23 is formed to a length equal to or greater than the span length of two adjacent new substructures 20. Therefore, the new superstructure 23 is erected between the two adjacent new substructures 20. The new superstructure 23 may be formed to a length that allows it to cross the river 9. Furthermore, in the new superstructure construction process S8, the new superstructure 23 is installed on the new substructure 20 using the launching equipment 91, but this is not limiting, and for example, a platform (not shown) with jacking equipment may be placed on a barge (not shown) floating on the river 9, and the new superstructure 23 placed on the platform may be lowered using the jacking equipment and installed on the new substructure 20. Also, a truss, arch, etc. may be constructed on the new superstructure 23 as necessary.

[0031] <Pier removal process> As shown in Fig. 11, in the pier removal process S9, the pier 3 is removed. Specifically, the erection girder 33 is jacked up, the launching equipment 91 is installed on the pier substructure 30, and the erection girder 33 placed on the launching equipment 91 is pulled back in one direction along the bridge axis. In addition, the pier support base 32B and the surrounding member 32A are removed using a barge, and the multiple pier piles 31 are cut near the bottom of the river 9.

[0032] This completes the entire process of the bridge reconstruction method, and the replacement of the existing bridge 1 with the new bridge 2 is completed.

[0033] According to the bridge reconstruction method (pier construction method) of the first embodiment described above, the height of the pier substructure 30 is set to be equal to or higher than the HWL of the river 9, so that it is not necessary to remove the pier 3 (the erection girder 33) during the flood season of the river 9. This allows the construction of the bridge (reconstruction work) to be continued using the pier 3 even during the flood season. As a result, bridge construction (year-round construction) is possible throughout the year, and the construction period for bridge reconstruction can be shortened. In addition, since the pier substructure 30 and the new substructure 20 are arranged in a row along the flow direction, it is possible to suppress the pier substructure 30 from obstructing the water flow of the river 9. In addition, it is also possible to leave the pier substructure 30 after replacing it with the new bridge 2 without completely removing it, which further shortens the construction period and reduces the cost related to the bridge reconstruction. In addition, a general pier (not shown) is often constructed by connecting multiple simple girders, and has inferior earthquake resistance compared to a continuous girder. In contrast, according to the bridge reconstruction method (pier construction method) of the first embodiment, the erection girder 33 including the hand-stretched girder 33A is a continuous girder capable of crossing the river 9, and therefore the earthquake resistance of the pier 3 utilizing this erection girder 33 can be improved.

[0034] Moreover, according to the bridge reconstruction method of the first embodiment, the pier 3 can be constructed by laterally moving (taking over) the erection girder 33 already installed on the existing bridge 1 onto the pier substructure 30. This allows the pier 3 to be constructed in a shorter time than when the erection girder 33, which has been pulled back from the existing bridge 1 in the bridge axis direction, is pushed out in the bridge axis direction toward the pier substructure 30. Furthermore, according to the bridge reconstruction method of the first embodiment, the new bridge 2 can be constructed in approximately the same position as the existing bridge 1. This makes it possible to prevent the horizontal alignment of the existing bridge 1 and the new bridge 2 from being significantly changed. Furthermore, it is possible to reduce the effort and cost required for newly purchasing land when replacing the bridge with the new bridge 2.

[0035] [Second embodiment: Bridge reconstruction method] Next, a bridge reconstruction method according to a second embodiment will be described with reference to Fig. 2 and Fig. 12. Fig. 12 is a cross-sectional view explaining the new superstructure construction step S81 of the bridge reconstruction method according to the second embodiment. In the following description, the same components as those in the bridge reconstruction method according to the first embodiment are given the same reference numerals, and descriptions similar to those in the bridge reconstruction method according to the first embodiment will be omitted.

[0036] In the bridge reconstruction method according to the second embodiment, as shown by the dashed line in Figure 2, a new superstructure construction process S81 differs from the new superstructure construction process S8 in the bridge reconstruction method according to the first embodiment.

[0037] As shown in Fig. 12, in the new superstructure construction process S81, a temporary beam 41 extending toward the new substructure 20 is attached to the upper part of the pier substructure 30. Note that the travel crane 93 and rail equipment 92 installed on the erection girder 33 are removed.

[0038] Next, a plurality of lateral transfer equipment 96 are placed on the temporary beams 41 and the new substructure 20 at intervals in the direction of flowing water, and the jacked-up erection girder 33 is placed on the lateral transfer equipment 96. The lateral transfer equipment 96 moves the erection girder 33 used for constructing the new substructure 20 laterally in the direction of flowing water from the pier substructure 30 to the new substructure 20 (see the white arrow in FIG. 12). The erection girder 33 is installed on the new substructure 20 along the bridge axis direction, and is used as the new superstructure 23 (see FIG. 11). After the lateral movement of the erection girder 33, the temporary beams 41 and the lateral transfer equipment 96 are removed. In the pier removal process S9 that is performed after this, only the pier substructure 30 is dismantled.

[0039] According to the bridge reconstruction method according to the second embodiment described above, the new bridge 2 can be constructed by laterally moving (taking over) the erection girder 33 that constituted the pier 3 onto the new substructure 20. In other words, the erection girder 33 of the pier 3 can be reused as the new superstructure 23. This allows the removal of the erection girder 33 and the installation of the new superstructure 23 to be carried out in a single process, thereby shortening the construction period.

[0040] In the bridge reconstruction method (pier construction method) according to the first and second embodiments, the pier pile prior installation step S2 is performed after the steel pipe sheet pile prior installation step S1, but it may be performed before the steel pipe sheet pile prior installation step S1. Also, the pier pile prior installation step S2 is performed prior to the pier substructure construction step S4, and the pier piles 31 are installed in advance, but the present invention is not limited to this. For example, the pier pile prior installation step S2 may be omitted, and the pier substructure construction step S4 may include a step of installing the pier piles 31. Also, the steel pipe sheet pile prior installation step S1 is performed prior to the new substructure construction step S7, and some of the permanent steel pipe sheet piles 40 are installed in advance, but the present invention is not limited to this. For example, the steel pipe sheet pile prior installation step S1 may be omitted, and the new substructure construction step S7 may include a step of installing all of the permanent steel pipe sheet piles 40. In addition, for example, the pier substructure construction process S4 may include a process of driving all of the permanent steel pipe sheet piles 40.

[0041] In the bridge reconstruction methods according to the first and second embodiments, a part of the existing subworks 10 is removed in the existing subworks removal step S6, but this is not limiting, and the entire existing subworks 10 may be removed. In this case, for example, the new subworks 20 may be formed by burying a new caisson (not shown) and erecting the new structure 22 on the caisson.

[0042] In the bridge reconstruction method according to the first and second embodiments, the pier substructure construction process S4 is performed after the existing superstructure removal process S3, but the present invention is not limited to this. The pier substructure construction process S4 may be performed at the same time as the existing superstructure removal process S3, or may be performed before the existing superstructure removal process S3. In addition, the pier removal process S9 is performed after the new superstructure construction process S8, but the present invention is not limited to this. The pier removal process S9 may be performed at the same time as the new superstructure construction process S8, or may be performed before the new superstructure construction process S8.

[0043] In the bridge reconstruction methods according to the first and second embodiments, the pier piles 31 of the pier 3 are cut in the pier removal step S9, but this is not limiting and the pier piles 31 may be pulled out and removed. Furthermore, if certain conditions are met, such as not obstructing the water flow of the river 9, the pier piles 31 and the permanent steel pipe sheet piles 40 do not need to be removed.

[0044] In the bridge reconstruction methods (pier construction methods) according to the first and second embodiments, the pier 3 (pier piles 31, etc.) is provided on the upstream side of the flowing water direction, but it may be provided on the downstream side of the flowing water direction. Also, the bridge crosses the river 9 diagonally when viewed from above, but it may cross in a direction approximately perpendicular to the flowing water direction (not shown).

[0045] In addition, the substructure of the bridge exemplified in the bridge reconstruction methods according to the first and second embodiments is a so-called caisson foundation having a caisson 11 (the new substructure 20 is a so-called steel pipe sheet pile foundation), but the foundation structure is not limited to this and may be, for example, a pile foundation (not shown). In other words, the substructure of the bridge may be any foundation structure buried underground.

[0046] The bridge reconstruction method according to the first and second embodiments shows one embodiment, and the order of steps may be changed in various ways without departing from the spirit of the technical concept.

[0047] [First embodiment: Bridge construction method] Next, the bridge construction method according to the first embodiment will be described with reference to Fig. 13 and Fig. 14. Fig. 13 is a flowchart showing the bridge construction method. Fig. 14 is a cross-sectional view explaining the new substructure construction step S71 and the new superstructure construction step S8 of the bridge construction method. In the following explanation, the same components as those in the bridge reconstruction method according to the first embodiment are given the same reference numerals, and explanations similar to those in the bridge reconstruction method according to the first embodiment will be omitted. In the following explanation, the drawings explaining the bridge reconstruction method according to the first embodiment will be referred to as appropriate.

[0048] The bridge construction method is a method for constructing a new bridge that crosses a river 9 using a pier 3. As shown in Fig. 13, the bridge construction method according to the first embodiment includes a pier substructure construction step S41, a pier erection step S51, a new substructure construction step S71, a new superstructure construction step S8, and a pier removal step S9. That is, in the bridge construction method according to the first embodiment, since it is not necessary to remove (dismantle) the existing bridge 1, the steel pipe sheet pile advance installation step S1, the pier pile advance installation step S2, the existing superstructure removal step S3, and the existing substructure removal step S6 in the bridge reconstruction method according to the first embodiment are omitted.

[0049] <Pier substructure construction process> In the pier substructure construction process S41, for example, a barge carrying heavy machinery such as a pile driver is used to drive a plurality of pier piles 31, and a surrounding member 32A and a pier support 32B are installed on the upper part of the plurality of pier piles 31 to construct the pier substructure 30 (see FIG. 6). The pier substructure 30 is constructed at a position spaced apart from the new substructure 24 of the new bridge 2 (to be constructed) on one side in the flowing water direction and at a distance equal to that of the new substructure 24 in the bridge axis direction. The pier substructure 30 is provided so as to be aligned with the new substructure 24 in the flowing water direction. The pier substructure 30 is constructed at a height equal to or higher than the HWL. In the bridge construction method according to the first embodiment, since the erection girder 33 is not moved laterally, the upper end of the pier substructure 30 may be located below (or above) the upper end of the new substructure 24 as long as it is equal to or higher than the HWL. Here, the pier substructure 30 is constructed at approximately the same height as the new substructure 24. The phrase "the pier substructure 30 is spaced apart from the new substructure 24 in the direction of flowing water" means that the pier substructure 30 is separated from the new substructure 24 by a space, and the space is an appropriate distance for easy construction (work) (for example, 5 m or less). The phrase "the pier substructure 30 is constructed at a position spaced apart from the new substructure 24 in the bridge axis direction" does not only mean that the pier substructure 30 matches the span length of the new substructure 24, but also means that a slight shift in the bridge axis direction is permitted depending on the conditions at the site. The phrase "the pier substructure 30 is at approximately the same height as the new substructure 24" does not only mean that the top ends of the pier substructure 30 and the new substructure 24 match, but also means that an error (step) is permitted to the extent that does not impair workability in the subsequent process.

[0050] <Pier construction process> In the pier erection process S51, a plurality of launching equipment 91 (see FIG. 5) is arranged on the pier substructure 30, and the jacked-up erection girders 33 are placed on the launching equipment 91 and launched from one side in the bridge axial direction to the other. In this manner, the erection girders 33 are installed on the pier substructure 30 along the bridge axial direction, and the pier 3 is constructed. Rail equipment 92 is installed on the erection girders 33, and a traveler crane 93 or the like is installed on the rail equipment 92 so as to be able to travel (see FIG. 14). The pier substructure construction process S41 and the pier erection process S51 described above are one example of a pier construction method for constructing the pier 3.

[0051] <New substructure construction process> In the new substructure construction process S71, the new substructure 24 is constructed using the pier 3. Specifically, as shown in FIG. 14, a waterstop wall 40A is constructed by driving a plurality of permanent steel pipe sheet piles 40 (S71-1), and a work platform 42 is installed around the plurality of permanent steel pipe sheet piles 40 using a travel crane 93 or the like. Next, a new structure 22 is constructed inside the waterstop wall 40A using a heavy machine 97 arranged on the work platform 42 (S71-2). The new substructure 24 is a steel pipe sheet pile foundation including a plurality of permanent steel pipe sheet piles 40 and the new structure 22. After the new substructure 24 is constructed, the work platform 42 is removed.

[0052] Next, in a new superstructure construction process S8, the new superstructure 23 is installed along the bridge axis direction on top of the new substructure 24, and in a pier removal process S9, the pier 3 is removed. With the above, all steps of the bridge construction method are completed, and the new bridge 2 is constructed.

[0053] According to the bridge construction method of the first embodiment described above, it is possible to obtain the same effects as the bridge reconstruction method of the first embodiment, such as making it possible to construct a new bridge 2 using the pier 3 all year round.

[0054] [Second embodiment: Bridge construction method] Next, a bridge reconstruction method according to the second embodiment will be described. In the following description, the same components as those in the bridge construction method according to the first embodiment will be given the same reference numerals, and explanations similar to those in the bridge construction method according to the first embodiment and the bridge reconstruction methods according to the first and second embodiments will be omitted. In the following description, the drawings explaining the bridge reconstruction methods according to the first and second embodiments will be referred to as appropriate.

[0055] The bridge construction method according to the second embodiment includes a new superstructure construction step S81 (see the dashed line in FIG. 2) similar to the bridge reconstruction method according to the second embodiment. That is, the erection girder 33 used for constructing the new substructure 24 is moved laterally from the pier substructure 30 toward the new substructure 24, and is installed on the new substructure 24 to be used as the new superstructure 23 (see FIG. 12). In addition, in the bridge construction method according to the second embodiment, in order to move the erection girder 33 laterally, in the pier substructure construction step S4, the pier substructure 30 is constructed to be equal to or higher than the HWL and to a height approximately equal to that of the new substructure 24. In addition, the fact that the pier substructure 30 is at a height approximately equal to that of the new substructure 24 does not only mean that the upper ends of the pier substructure 30 and the new substructure 24 are aligned, but also means that an error (step) is allowed to the extent that it does not hinder the lateral movement of the erection girder 33 to the new substructure 24 in the new superstructure construction step S81.

[0056] In the bridge construction method of the second embodiment described above, as in the bridge reconstruction method of the second embodiment, the construction period can be shortened by reusing the erection girder 33 of the pier 3 as the new superstructure 23.

[0057] It should be noted that the substructure of the bridge exemplified in the bridge construction methods according to the first and second embodiments was a so-called steel pipe sheet pile foundation, but is not limited to this. For example, it may be a so-called caisson foundation, similar to the substructure of the bridge exemplified in the bridge reconstruction methods according to the first and second embodiments, or it may be a pile foundation (not shown).

[0058] Furthermore, the bridge construction methods according to the first and second embodiments show only one mode, and the order may be changed in various ways without departing from the spirit of the technical concept.

[0059] In the bridge reconstruction method according to the first embodiment and the bridge construction method according to the first embodiment, the pier 3 (pier substructure 30) is removed in the pier removal step S9 after the completion of the new superstructure construction step S8, but the present invention is not limited to this. For example, as another new superstructure construction step, as shown in FIG. 15, the erection girder 33 used as the pier 3 may be moved laterally from the pier substructure 30 onto the new substructures 20, 24 and connected to the tip of the new superstructure 23 in the sending direction to be used as a hand-stretched girder (modified example). The procedure for moving the erection girder 33 laterally is the same as the new superstructure construction step S81 of the bridge reconstruction method according to the second embodiment. The new superstructure 23 to which the erection girder 33 (hand-stretched girder) is connected is sent out from one side in the bridge axial direction to the other side by the same procedure as the above-mentioned new superstructure construction step S8, and installed on the new substructure 20. According to this configuration, the installation of the new superstructure 23 and the removal of the erection girder 33 can be carried out at the same time, shortening the construction period.

[0060] [Third embodiment: Bridge reconstruction method] However, since existing bridges 1 such as road bridges and railway bridges ensure a large volume of traffic and support the movement of people and the distribution industry, it is not desirable to close the existing bridge 1 for a long period of time when reconstructing the existing bridge 1. With the bridge reconstruction methods according to the first and second embodiments described above, it was not possible to avoid closing the existing bridge 1 to traffic during the period when the existing bridge 1 was removed and reconstructed. Therefore, with the bridge reconstruction method according to the third embodiment, it is possible to ensure traffic during the period when the existing bridge 1 is removed and reconstructed.

[0061] A bridge reconstruction method according to the third embodiment will be described with reference to Figs. 16 to 19. Fig. 16 is a flowchart showing the bridge reconstruction method according to the third embodiment. Fig. 17 is a step diagram explaining the bridge reconstruction method according to the third embodiment. Fig. 18 is a plan view showing a temporary road formed by a temporary superstructure 51 and a connecting section 52. Fig. 19 is a step diagram explaining a rotary slide method. In the following explanation, the same components as those in the bridge reconstruction methods according to the first and second embodiments are given the same reference numerals, and explanations similar to those in the bridge reconstruction methods according to the first and second embodiments will be omitted.

[0062] As shown in Fig. 16, the bridge reconstruction method according to the third embodiment includes, in addition to the above-mentioned steps S1 to S9 (excluding the new superstructure construction step S8), a temporary substructure construction step S10, a temporary superstructure construction step S11, a temporary road opening step S12, and a temporary structure removal step S13. This bridge reconstruction method also includes a new superstructure construction step S82 that is different from the new superstructure construction steps S8,81.

[0063] <Temporary substructure construction process> As shown in FIG. 17(A), in the temporary substructure construction process S10, a temporary substructure 50 is constructed in a position spaced apart from the existing substructure 10 in the flow direction of the river 9 on the opposite side (downstream side in FIG. 17) of the pier 3 (to be constructed in a later process) to the existing substructure 10, to be used temporarily in a section corresponding to the existing superstructure 13 to be removed. For example, a pile bent foundation using piles or the like can be adopted for the temporary substructure 50, and the temporary substructure 50 is constructed using heavy machinery 90 mounted on a barge (not shown). Even during the period in which the temporary substructure 50 is being constructed, vehicles and the like pass over the existing superstructure 13. In other words, the temporary substructure construction process S10 is carried out while the existing bridge 1 is open to traffic.

[0064] <Temporary superstructure construction process> As shown in FIG. 17B, in the temporary superstructure construction process S11, a temporary superstructure 51 that is used temporarily is constructed (installed) on the temporary substructure 50 along the bridge axis direction. The temporary superstructure 51 is installed on the temporary substructure 50 to form a temporary bridge (temporary structure). The installation method of the temporary superstructure 51 is the same as the construction method of the new superstructure 23 in the new superstructure construction process S8. For example, the temporary superstructure 51 may be launched onto the temporary substructure 50 using a launching facility 91, or may be installed on the temporary substructure 50 using a jacking facility mounted on a barge. Even during the period in which the temporary superstructure 51 is being constructed, vehicles and the like pass over the existing superstructure 13. In other words, the temporary superstructure construction process S11 is carried out while the existing bridge 1 is open to traffic.

[0065] <Temporary road opening process> In the temporary road opening process S12, a temporary road passing through the temporary superwork 51 is formed. Specifically, as shown in Fig. 18, a connecting section 52 is provided connecting the temporary superwork 51 and a general section 53 (a road connecting to the existing bridge), and a temporary road is formed by this connecting section 52 and the temporary superwork 51. In the temporary road opening process S12, after the temporary road is formed, traffic on the temporary road is opened and traffic on the existing bridge 1 is closed. Note that the opening of the temporary road and the closing of the existing bridge 1 may be performed in either order, or they may be performed in parallel at the same time.

[0066] <Existing superstructure removal process, etc.> After the temporary road opening step S12, the existing superstructure removal step S3 is carried out, which is the same as the bridge reconstruction method according to the first and second embodiments. To be precise, after the temporary road opening step S12, the steel pipe sheet pile advance installation step S1, the pier pile advance installation step S2, the existing superstructure removal step S3, the pier substructure construction step S4, the pier erection step S5, the existing substructure removal step S6, and the new substructure construction step S7 are carried out. As shown in FIG. 17(C), the pier 3 is constructed on the opposite side (upstream side in FIG. 17) of the temporary structure (temporary substructure 50, temporary superstructure 51) across the new substructure 20. The pier pile advance installation step S2 and the pier substructure construction step S4 may be carried out before the temporary substructure construction step S10, the temporary superstructure construction step S11, or the temporary road opening step S12, for example, using a barge or the like, or may be carried out at the same time as these.

[0067] <New superstructure construction process> In the new superstructure construction process S82, traffic between the existing bridge 1 (existing superstructure 13) and the temporary road is closed (the existing bridge 1 has already been closed). Next, as shown in FIG. 17(C), the temporary superstructure 51 is jacked up on the temporary substructure 50, and the relocated track RL is laid across the temporary substructure 50 and the new substructure 20. The temporary superstructure 51 is moved laterally from the temporary substructure 50 to the new substructure 20 along the relocated track RL using a horizontal jack or the like. As shown in FIG. 17(D), the temporary superstructure 51 is installed on the new substructure 20 and used as the new superstructure 23. After the temporary superstructure 51 is moved onto the new substructure 20, the relocated track RL is removed. In addition, in the new superstructure construction process S82, traffic on the new superstructure 23 is opened.

[0068] Incidentally, as shown in FIG. 19(A), the end of the temporary superstructure 51 including the connecting section 52 in the bridge axis direction (hereinafter referred to as the "end temporary superstructure 51E") may be installed on the temporary substructure 50 installed in parallel along a direction inclined (or approximately perpendicular) to the bridge axis direction of the existing bridge 1. In other words, the end temporary superstructure 51E may be arranged in a direction inclined (or approximately perpendicular) to the bridge axis direction. Therefore, in the new superstructure construction process S82, the end temporary superstructure 51E is installed on the new substructure 20 by a method of sliding with rotation (referred to as the "rotation slide method" in this specification). In the rotation slide method, the end temporary superstructure 51E is slid toward the general section 53 as necessary, as shown in FIG. 19(B). Next, as shown in Figure 19(C), the end temporary superstructure 51E is installed on the new substructure 20 by rotating it around the general section 53 side (counterclockwise in Figure 19(C)). When performing sliding involving rotation, a relocation track RL is erected between the temporary substructure 50 and the new substructure 20, and the end temporary superstructure 51E slides on the relocation track RL. The above-mentioned rotational sliding method is one example, and the method may be modified in various ways as long as it does not deviate from the spirit of the technical idea.

[0069] <Pier removal process, temporary structure removal process> With the new superstructure 23 open to traffic, the pier 3 is removed in a pier removal process S9, and the temporary substructure 50 is removed in a temporary structure removal process S13 (see FIG. 17(D)). The temporary substructure 50 is cut near the bottom of the river 9, similar to the pier piles 31 of the pier substructure 30. Either the pier removal process S9 or the temporary structure removal process S13 may be performed first, or they may be performed in parallel at the same time.

[0070] This completes the entire process of the bridge reconstruction method, and the replacement of the existing bridge 1 with the new bridge 2 is completed.

[0071] According to the bridge reconstruction method of the third embodiment described above, it is possible to ensure traffic during the period in which the existing bridge 1 is removed and reconstructed, and the impact on current traffic can be reduced.

[0072] [Variations] Various modified examples of the bridge reconstruction method according to the first to third embodiments will be described below. In the following description, the same components as those in the bridge reconstruction method according to the first to third embodiments will be given the same reference numerals, and the same description as in the bridge reconstruction method according to the first to third embodiments will be omitted. In addition, the various modified examples described in this specification can be combined to the extent that they do not deviate from the spirit of the technical idea and are not inconsistent.

[0073] In the bridge reconstruction method according to the first to third embodiments, the existing superstructure 13 of the existing bridge 1 is entirely removed in the existing superstructure removal step S3, but the present invention is not limited thereto. In the existing superstructure removal step S3, the erection girder 33 may be installed on the existing bridge 1 (on the existing superstructure 13), and a part of the existing superstructure 13 of the existing bridge 1 may be removed using the erection girder 33. That is, it is sufficient that at least a part of the existing superstructure 13 is set as the target section to be removed and reconstructed. In this case, in the new superstructure construction steps S8 and S81 of the bridge reconstruction method according to the first and second embodiments, the new superstructure 23 is constructed along the bridge axis direction on the new substructure 20 at the position (target section) where the existing superstructure 13 is removed using the pier 3. In addition, in the temporary substructure construction step S10 of the bridge reconstruction method according to the third embodiment, a temporary substructure 50 to be temporarily used in the section corresponding to at least a part of the existing superstructure 13 is constructed. Naturally, the temporary superstructure 51 is also constructed in a section corresponding to at least a part of the existing superstructure 13. Furthermore, in the new superstructure construction process S82, the temporary superstructure 51 that has been moved laterally is installed on the new substructure 20 at the position where the existing superstructure 13 has been removed, and is used as the new superstructure 23.

[0074] Furthermore, in the bridge reconstruction method according to the third embodiment, when the target section is part of the existing superwork 13, the connecting section 52 may be provided to connect the temporary superwork 51 and the existing superwork 13 excluding the target section. When the target section is part of the existing superwork 13, since the work of forming a temporary road will affect traffic in the target section, it is advisable to form the temporary road after closing traffic in the target section, and open traffic on the temporary road while keeping traffic in the target section closed.

[0075] In the bridge reconstruction methods according to the first to third embodiments, in the existing substructure removal step S6, a part or the whole of the existing substructure 10 is removed using the pier 3, and in the new substructure construction step S7, the new substructure 20 is reconstructed in place of the existing substructure 10 removed using the pier 3, but the present invention is not limited thereto. As shown in FIG. 20, instead of the existing substructure removal step S6 and the new substructure construction step S7, a substructure improvement step S15 may be performed after the pier erection step S5 (after the construction of the pier 3) to reinforce at least a part of the existing substructure 10 using the pier 3. The existing substructure 10 can be reinforced by various construction methods, such as steel plate wrapping, reinforced concrete wrapping, or ground anchors. Note that FIG. 20 shows a modified example of the bridge reconstruction method according to the first to second embodiments, but the substructure improvement step S15 can also be applied to the bridge reconstruction method according to the third embodiment (not shown).

[0076] Furthermore, when the substructure improvement process S15 is carried out, in the new superstructure construction processes S8 and S81 of the bridge reconstruction method according to the first and second embodiments, the new superstructure 23 is constructed along the bridge axis direction on the (reinforced) existing substructure 10 at the position (target section) where the existing superstructure 13 was removed using the pier 3. In the new superstructure construction process S82 of the bridge reconstruction method according to the third embodiment, the temporary superstructure 51 that has been moved laterally is installed along the bridge axis direction on the (reinforced) existing substructure 10 at the position (target section) where the existing superstructure 13 was removed, and is used as the new superstructure 23. Note that the substructure improvement process S15 may be regarded as a process including the existing substructure removal process S6 and the new substructure construction process S7, and may include removing at least a part of the existing substructure 10 using the pier 3 and constructing the new substructure 20.

[0077] Furthermore, when reinforcement, removal, or reconstruction of the existing subworks 10 is not required, in other words, when only replacing the existing superworks 13, the existing subworks removal step S6, the new subworks construction step S7, and the subworks improvement step S15 may be omitted (not shown). That is, after removing the target section of the existing superworks 13 and constructing the pier 3, the new superwork construction steps S8, S81, and S82 are carried out to construct the new superwork 23 on the existing subworks 10 at the position (target section) from which the existing superworks 13 was removed.

[0078] In the bridge reconstruction method according to the first to third embodiments, the erection girder 33 is installed on the existing superstructure 13 in the existing superstructure removal step S3 in order to remove a part or the whole of the existing superstructure 13, but the present invention is not limited thereto. As shown in FIG. 21, the bridge reconstruction method according to another modification includes a pier substructure construction step S41 and a pier erection step S51 similar to the bridge construction method according to the first to second embodiments, and the pier substructure construction step S41 and the pier erection step S51 may be performed prior to the existing superstructure removal step S31. In this case, the erection girder 33 is not installed on the existing superstructure 13 in the existing superstructure removal step S3. In the pier erection step S51, the jacked-up erection girder 33 is placed on the delivery equipment 91 and delivered from one side in the bridge axial direction to the other, so that the erection girder 33 is installed on the pier substructure 30 along the bridge axial direction, and the pier 3 is constructed. As another method for installing the erection girder 33 on the pier subwork 30 in the pier erection process S51, the erection girder 33 assembled on the ground on the existing bridge 1 (existing superstructure 13) may be installed on the pier subwork 30 by moving laterally from the existing bridge 1 toward the pier subwork 30 in the flowing water direction (not shown). As another method for installing the erection girder 33 on the pier subwork 30 in the pier erection process S51, the erection girder 33 assembled on the ground at a place other than the existing bridge 1 may be moved by heavy equipment 90 such as a crawler crane to be installed on the pier subwork 30 (not shown).

[0079] In the bridge reconstruction method according to another modification shown in FIG. 21, after the construction of the pier 3, an existing superstructure removal step S31 is carried out in which at least a part of the existing superstructure 13 of the existing bridge 1 is removed using the pier 3. Specifically, a rail system 92 and a traveler crane 93 are installed on the pier 3, and the existing superstructure 13 is removed using the traveler crane 93 or the like (not shown). Alternatively, the existing superstructure 13 may be removed by heavy machinery such as a crawler crane placed on the pier 3 (not shown). After the existing superstructure removal step S31, an existing substructure removal step S6, a new substructure construction step S7, and new superstructure construction steps S8, S81 are carried out. Note that FIG. 21 shows another modification of the bridge reconstruction method according to the first and second embodiments, but the features of this other modification can also be applied to the bridge reconstruction method according to the third embodiment (not shown). Furthermore, when the existing subwork 10 is reinforced, the subwork improvement process S15 is carried out instead of the existing subwork removal process S6 and the new subwork construction process S7 (not shown). Furthermore, when reinforcement, removal, or reconstruction of the existing subwork 10 is not required, the existing subwork removal process S6, the new subwork construction process S7, and the subwork improvement process S15 are omitted (not shown). The existing superwork 13 may be removed by being sent out in the bridge axis direction (not shown).

[0080] In the new superstructure construction step S81 of the bridge reconstruction method according to the second embodiment, the erection girder 33 is moved laterally in the flowing water direction from the pier substructure 30 toward the existing substructure 10 or the new substructure 20, and installed on the existing substructure 10 or the new substructure 20 to be used as the new superstructure 23, but the present invention is not limited to this. As shown in Fig. 22, in another new superstructure construction step S83, the new superstructure 23 may be installed on the erection girder 33 of the pier 3, moved laterally in the flowing water direction from the erection girder 33 toward the new substructure 20 (or the existing substructure 10), and installed on the new substructure 20 (or the existing substructure 10).

[0081] In the bridge reconstruction method according to the third embodiment, the temporary superstructure 51 is moved laterally and used as the new superstructure 23 in the new superstructure construction step S82, but the present invention is not limited to this. As another new superstructure construction step S82, a rail system 92 or a traveling crane 93 may be installed on the pier 3, and the new superstructure 23 may be constructed using the traveling crane 93 (not shown), or a heavy machine such as a crawler crane directly placed on the pier 3 may be used to construct the new superstructure 23 pre-assembled on the ground. Instead of the new superstructure construction step S82, the new superstructure construction step S8 in the bridge reconstruction method according to the first embodiment, or the new superstructure construction step S81 in the bridge reconstruction method according to the second embodiment, or the above-mentioned new superstructure construction step S83 may be performed (not shown). Furthermore, in the bridge reconstruction method of the third embodiment, instead of the new superstructure construction process S82, as explained using Figure 15, the erection girder 33 used as the pier 3 may be moved laterally from the pier substructure 30 onto the new substructure 20 and connected to the tip of the new superstructure 23 in the sending-out direction, thereby being used as a hand-stretched girder.

[0082] Furthermore, in the bridge reconstruction methods according to the first to third embodiments and the bridge construction methods according to the first and second embodiments, multiple permanent steel pipe sheet piles 40 are driven to construct the water-stopping wall 40A, but instead, multiple steel sheet piles, steel pipe piles, steel panels, etc. (none of which are shown) may be driven.

[0083] The above embodiment is merely an example of the pier construction method, bridge reconstruction method, and bridge construction method according to the present invention, and the technical scope of the present invention is not limited to the above embodiment. The present invention may be modified, substituted, or altered in various ways without departing from the spirit of the technical concept, and the claims include all embodiments that may be included within the scope of the technical concept. [Explanation of symbols]

[0084] 1 Existing bridge (bridge) 2 New bridge (bridge) 3. Pier 9. Rivers 10 Existing substructure 13 Existing superstructure 20,24 New substructure 23 New Superstructure 30 Pier Substructure 33 Construction girder 50 Temporary substructure 51 Temporary superstructure S3, S31 Removal of existing superstructure S4, S41 Pier substructure construction process S5, S51 Pier construction process S6 Existing substructure removal process S7,S71 New substructure construction process S8, S81, S82, S83 New superstructure construction process S10 Temporary substructure construction process S11 Temporary superstructure construction process S12 Temporary road opening process S15 Substructure improvement process

Claims

1. A method for constructing a pier for use in constructing a bridge across a river and for operating a construction machine, comprising: A pier substructure construction process for constructing the pier substructure; and a pier erection process for installing the erection girder sent out from one side to the other in the bridge axial direction on the pier substructure. A pier construction method comprising:

2. In the pier substructure construction step, the pier substructure is constructed to a height equal to or higher than the planned high water level of the river.

2. The method of claim 1, wherein the pier is constructed in a manner similar to that described in claim 1.

3. In the pier erection process, the erection girder is installed on three or more of the pier substructures so as to form a continuous girder.

3. A pier construction method according to claim 1 or 2.

4. A method for constructing a pier for use in constructing a bridge across a river and for operating a construction machine, comprising: A pier substructure construction process for constructing a pier substructure that is higher than the planned high water level of the river; and a pier erection process for installing an erection girder on the pier substructure, In the pier erection process, the erection girder is installed on three or more of the pier substructures so as to form a continuous girder. A pier construction method comprising:

5. A method for constructing a new bridge across a river using a pier, comprising: A pier substructure construction process for constructing the pier substructure; a pier erection process in which an erection girder sent out from one side to the other in the bridge axial direction is installed on the pier substructure; A new substructure construction process for constructing a new substructure using the pier; A new superstructure construction process for constructing a new superstructure on the new substructure using the pier. A bridge construction method comprising:

6. A method for constructing a new bridge across a river using a pier, comprising: A pier substructure construction process for constructing the pier substructure; a pier erection process in which an erection girder sent out from one side to the other in the bridge axial direction is installed on the pier substructure; A new substructure construction process for constructing a new substructure using the pier; A new superstructure construction process is provided in which a new superstructure is installed on the erection girder, the new superstructure is moved laterally from the erection girder toward the new substructure, and the new superstructure is installed on the new substructure. A bridge construction method comprising:

7. The pier is continuously used without being removed even during flood season of the river.

7. A method for constructing a bridge according to claim 5 or 6.

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