Slab replacement method

Abstract

To effectively reduce construction time.SOLUTION: During traffic opening hours, opening-hour work is carried out in a first work zone F1 that is designated in an area of a bridge 2 that does not include areas where vehicles are allowed for traffic, and during traffic restriction hours, restriction-hour work is carried out in a second work zone F2 that is designated, in addition to the first work zone F1, extending into the area on a restricted lane L1 side. The restriction-hour work includes a first cutting and removal step in which existing slabs 10 located within the first work zone F1 are cut to form first existing slab pieces 10A1 and the first existing slab pieces 10A1 are removed to expose at least one of main girders 20G5 at a first removal location X1. The opening-hour work includes a pre-installation processing step in which pre-installation processing is performed on the main girders 20G5 exposed at the first removal location X1, and moreover, the restriction-hour work further includes a new slab installation step in which new slabs 30 are installed at the first removal location X1 where the main girders 20G5 that have been subjected to pre-installation processing are exposed.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a deck replacement method for replacing an existing deck of a bridge with a new deck. [Background technology]

[0002] Decks of road bridges and other structures need to be replaced due to deterioration of concrete over many years of use, corrosion of internal rebars, etc. Renovation work to replace existing decks with new decks involves traffic restrictions that restrict vehicle traffic, but it is necessary to minimize the impact on the surrounding traffic environment by keeping the time of traffic restrictions as short as possible.

[0003] For example, Patent Document 1 discloses a deck replacement method in which an existing deck is replaced with a new deck by alternating between nighttime traffic restriction periods and daytime traffic opening periods. In the method described in Patent Document 1, one cycle of work from removing the existing deck to installing the new deck is divided into three steps, and only one step is carried out during one nighttime traffic restriction period, ensuring that the work is completed before the daytime traffic opening. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2021-001536 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the construction method described in Patent Document 1, work is not performed during daytime traffic opening hours, but only during nighttime traffic restriction hours. This limits the amount of work that can be performed during one traffic restriction period, and there is an issue that it takes time to replace the deck. Specifically, the work is divided into three processes, and only one process is performed during traffic restriction hours, so one cycle from removing the existing deck to installing the new deck takes at least three days, and there is room for improvement in shortening the construction period.

[0006] The technology disclosed herein has been made in consideration of the above circumstances, and aims to provide a technology relating to a deck replacement construction method that can effectively shorten construction time. [Means for solving the problem]

[0007] The deck replacement method disclosed herein is as follows: The method includes replacing an existing deck (10) installed on a plurality of main girders (20) arranged in parallel at a predetermined interval in a direction perpendicular to the bridge axis of a bridge (2) with a new deck (30) by alternately repeating an opening operation performed during a traffic opening time when at least some or all of the lanes (L1, L2) are opened and a traffic restriction operation performed during a traffic restriction time when some of the lanes (L1, L2) are restricted, During the traffic opening time period, the opening work is carried out in a first work zone (F1) that is set in an area of ​​the bridge (2) that does not include an area through which vehicles can pass, During the traffic regulation time period, the traffic regulation work is carried out not only in the first work zone (F1) but also in a second work zone (F2) that is set by extending the first work zone (F1) to the area on the lane (L1) side to be regulated, The restriction work includes a first cutting and removal process in which at least a portion of the existing deck slab (10) located within the first work zone (F1) is cut to form a first existing deck slab piece (10A1), and the first existing deck slab piece (10A1) is removed to expose at least one or more main girders (20G5) among the multiple main girders (20) at a first removal location (X1) where the first existing deck slab piece (10A1) has been removed; The opening work includes a pre-installation processing step of performing pre-installation processing that needs to be performed before installing the new deck (30) on the main girder (20G5) exposed at the first removal location (X1), The regulated work further includes a new deck installation process of installing the new deck (30) at the first removal location (X1) where the main girder (20G5) on which the pre-installation treatment has been performed is exposed.

[0008] In the deck replacement method disclosed herein, The pre-installation treatment preferably includes at least one of the following operations: scraping the upper flange (21) of the main girder (20), installing stud dowels (25), and applying anti-rust paint to perform anti-rust treatment.

[0009] In the deck replacement method disclosed herein, The regulated work further includes a second cutting and removal process of cutting the existing deck slab (10) adjacent in a direction perpendicular to the bridge axis to the first removal location (X1) where the main girder (205GG5) on which the pre-installation treatment was performed is exposed, the existing deck slab (10) having at least a portion located within the second work zone (F2) to form a second existing deck slab piece (10A2), and removing the second existing deck slab piece (10A2); In the new deck installation process, it is desirable to install the new deck (30) at the first removal location (X1) and at the second removal location (X2) from which the second existing deck piece (10A2) was removed.

[0010] In the deck replacement method disclosed herein, If, during the regulated work, at least one main girder (20G4) is exposed at the second removal location (X2) as a result of the removal of the second existing deck piece (10A2), it is desirable to perform the pre-installation treatment on the main girder (20G4) before installing the new deck (30).

[0011] In the deck replacement method disclosed herein, During the period from the removal of the first existing deck slab piece (10A1) to the formation of the second existing deck slab piece (10A2), a temporary support member (50) is installed to temporarily support from below the existing deck slab (10) corresponding to the portion where the second existing deck slab piece (10A2) is to be formed. Here, it is desirable to install the temporary support member (50) when there is a possibility of causing an impediment to vehicle travel.

[0012] In another aspect of the deck replacement method of the present disclosure, The regulation work is as follows: a second cutting and removal process in which, in addition to the first existing deck piece (10A1), an existing deck (10) adjacent to the first existing deck piece (10A1) in the direction perpendicular to the bridge axis, at least a portion of which is located within the second work zone (F2), is cut to form a second existing deck piece (10A2) integrally or separately from the first existing deck piece (10A1), and the first existing deck piece (10A1) and the second existing deck piece (10A2) are removed integrally or separately; and a temporary deck installation step of installing a temporary deck (80) that does not cover the upper part of the main girder (20G5) exposed at the first removal location (X1) at a second removal location (X2) where the second existing deck piece (10A2) has been removed, prior to starting the opening work. In the new deck installation process, it is desirable to remove the temporary deck (80) and then install the new deck (30) at the first removal location (X1) and the second removal location (X2).

[0013] In another aspect of the deck replacement method of the present disclosure, If, during the regulated work, at least one main girder (20G4) is exposed at the second removal location (X2) as a result of the removal of the second existing deck piece (10A2), it is desirable to perform the pre-installation treatment on the main girder (20G4) before installing the temporary deck (80).

[0014] In another aspect of the deck replacement method of the present disclosure, After the temporary floor slab (80) is installed, a temporary support member (50) is installed to temporarily support the temporary floor slab (80) from below until the temporary floor slab (80) is removed. Here, it is desirable to install the temporary support member (50) when there is a possibility that the temporary floor slab (80) may be hindered from traveling.

[0015] In the above description, in order to facilitate understanding of the present disclosure, the symbols used in the embodiments are added in parentheses to components corresponding to the embodiments, but each component is not limited to the embodiment defined by the symbol. Effect of the Invention

[0016] According to the technology disclosed herein, the construction period for a deck replacement construction method can be effectively shortened. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a schematic perspective view of an existing bridge. [Diagram 2] This is a schematic diagram explaining the flow of work for one cycle from removing the existing deck to installing the new deck. [Diagram 3] This is a flow diagram explaining the work flow for one cycle from removing the existing deck to installing the new deck. [Figure 4] FIG. 1 is a schematic diagram illustrating a typical deck replacement method that alternates between daytime traffic-open periods and nighttime traffic-restricted periods. [Diagram 5] FIG. 2 is a schematic top view illustrating the deck replacement method according to the first embodiment. [Figure 6] FIG. 2 is a schematic top view illustrating the work performed during traffic opening hours (daytime) in the deck replacement method according to the first embodiment. [Figure 7] 7 is a cross-sectional view taken along line AA in FIG. 6. [Figure 8] FIG. 2 is a schematic top view illustrating the first half of the work performed during traffic restriction hours (at night) in the deck replacement method according to the first embodiment. [Figure 9] 9 is a cross-sectional view taken along line AA in FIG. 8. [Figure 10] FIG. 11 is a schematic top view illustrating the latter half of the work performed during traffic restriction hours (at night) in the deck replacement method according to the first embodiment. [Figure 11] 11 is a cross-sectional view taken along line AA in FIG. 10. [Figure 12] 11 is a cross-sectional view taken along line BB in FIG. 10. [Figure 13] FIG. 1 is a flow diagram illustrating the flow of work performed during traffic open hours (daytime) in the deck replacement method according to the first embodiment. [Figure 14] FIG. 11 is a flow diagram illustrating the flow of work performed during traffic restriction hours (nighttime) in the deck replacement method according to the first embodiment. [Figure 15] FIG. 11 is a schematic top view illustrating the work performed during traffic opening hours (daytime) in the deck replacement method according to the second embodiment. [Figure 16] 16 is a cross-sectional view taken along line AA in FIG. 15. [Figure 17] FIG. 11 is a schematic top view illustrating the first half of the work performed during traffic restriction hours (at night) in the deck replacement method according to the second embodiment. [Figure 18] 18 is a cross-sectional view taken along line AA in FIG. 17. [Figure 19] FIG. 11 is a schematic top view illustrating the latter half of the work performed during traffic restriction hours (at night) in the deck replacement method according to the second embodiment. [Figure 20] 20 is a cross-sectional view taken along line AA in FIG. 19. [Figure 21] FIG. 21 is a schematic cross-sectional view showing the state in which the temporary deck is installed in FIG. 20. [Figure 22] FIG. 11 is a flow diagram illustrating the flow of work performed during traffic restriction hours (at night) in the deck replacement method according to the second embodiment. [Figure 23] FIG. 11 is a schematic cross-sectional view illustrating an existing deck piece according to a modified deck replacement method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the deck replacement method according to this embodiment will be described with reference to the accompanying drawings.

[0019] [Overview] First, before describing the details of this embodiment, an overall outline of a general deck replacement method will be described. FIG. 1 is a schematic perspective view of an existing bridge 1. The bridge 1 is, for example, a road bridge such as a motorway, and has a first bridge 2 for an upbound lane and a second bridge 3 for an downbound lane. The first bridge 2 includes, for example, an upbound driving lane L1 and an upbound passing lane L2 as lanes on which vehicles can travel. The second bridge 3 includes, for example, an downbound driving lane L4 and a downbound passing lane L3 as lanes on which vehicles can travel.

[0020] That is, the bridge 1 in the illustrated example is a four-lane road bridge (two lanes on each side) having four lanes L1 to L4. Shoulders S1 and S2 are provided at the ends of the width direction (direction perpendicular to the bridge axis X) of each of the bridges 2 and 3, respectively, to which vehicles can retreat in the event of an emergency. Note that the number of lanes of the bridge 1 to which the deck replacement method of this embodiment is applied is not limited to four lanes as in the illustrated example, and may be, for example, six lanes or more (three lanes on each side), or may be two lanes (one lane on each side).

[0021] One method of replacing the existing deck of bridge 1 with a new deck is the so-called "full-section deck replacement method," in which either bridge 1, 2 or 3, is completely closed to traffic, while the other bridge is restricted to two-way traffic. However, full-section construction that restricts two-way traffic makes it difficult to ensure sufficient traffic volume, and there are issues with the large impact it has on the surrounding traffic environment.

[0022] For this reason, the deck replacement method of this embodiment employs the so-called "half-section deck replacement method." In the half-section deck replacement method, for example, a temporary guard fence 5 is installed along the bridge axis direction Y at a substantially midpoint of the first bridge 2 in the direction perpendicular to the bridge axis X, thereby dividing the first bridge 2 into a work zone 6 for carrying out work and a traffic lane 7 for allowing vehicles to pass. In the work zone 6, a part of the existing deck 10 and a part of the wall balustrade 11 are removed. In the half-section deck replacement method, the traffic lane 7 can be used as a road on which vehicles can run (passing lane L2 in the illustrated example), so that traffic volume can be secured more effectively than when two-way traffic restrictions are implemented as in full-section construction. Such a half-section deck replacement method is also called a "width-direction division replacement method."

[0023] Below, an overview of the half-section deck replacement method will be explained using the construction of the first bridge 2 for the upbound lane as an example. Note that the construction of the second bridge 3 for the downbound lane will involve similar work, so an explanation will be omitted. Also, below, the first bridge 2 will be referred to simply as the "bridge", the upbound driving lane L1 will be referred to simply as the "driving lane", and the upbound passing lane L2 will be referred to simply as the "passing lane".

[0024] As shown in FIG. 1, in the half-section deck replacement method, the existing deck 10 and the wall parapet 11 of a part of the work zone 6 are cut and removed, and then a new deck (not shown) is installed at the removed location X, which is one cycle. This cycle is repeated in sequence along the bridge axis direction Y to replace the existing deck 10 in the work section D1 on the travel lane L1 side with a new deck. Also, before and after the construction of the work section D1, a similar cycle is repeated for the work section D2 on the passing lane L2 side, to replace the existing deck 10 in the work section D2 with a new deck. Thereafter, the existing deck 10 of the bridge 2 is replaced with a new deck by repeating the same cycle for the work sections D1 and D2 for the other work sections D3, D4, etc.

[0025] Fig. 2 is a schematic diagram illustrating the flow of one cycle of work from removing the existing deck to installing the new deck. Fig. 3 is a flow diagram illustrating the flow of one cycle of work.

[0026] As shown in Fig. 3, first, in step S100, cutting work of the existing deck 10 is performed (cutting process). Specifically, as shown in Fig. 2(A), a cutting line CL shown by a dashed line is set on the existing deck 10, and the existing deck 10 is cut into a substantially rectangular shape along this cutting line CL using a cutting device such as a concrete cutter (not shown), thereby forming the existing deck piece 10A. The size of the existing deck piece 10A is not particularly limited, but it is desirable that it be a size that allows transportation by vehicle after removal.

[0027] Next, in step S110, the existing deck slab piece 10A is removed (existing deck removal process). Specifically, as shown in FIG. 2(B), the existing deck slab piece 10A is removed using a deck hoisting device CR, such as a portal crane or a rough terrain crane, that can be installed on-site. When the existing deck slab piece 10A is removed, the steel main girder 20 is exposed at the removed location. The main girder 20 is, for example, an H-shaped steel or an I-shaped steel, and has an upper flange 21, a web 22, and a lower flange 23. Contaminants such as concrete pieces remain on the upper surface of the upper flange 21 that is exposed by removing the existing deck slab piece 10A.

[0028] Next, in step S120, pre-installation treatment is performed on the exposed upper flange 21 of the main girder 20 (pre-installation treatment step). The pre-installation treatment includes a so-called scraping work for removing remaining concrete and existing stud dowels on the upper surface of the upper flange 21, a stud dowel installation work for melt-fixing stud dowels 25 (see FIG. 2(C)) on the upper surface of the upper flange 21 by welding or the like, and a rust prevention treatment for applying an anti-rust paint or the like to the upper surface of the upper flange 21.

[0029] Next, in step S130, the new deck 30 is placed on the upper surface of the upper flange 21 (new deck placement process). Specifically, as shown in FIG. 2(C), the new deck 30 is placed on the upper surface of the upper flange 21 using a deck lifting device CR. The new deck 30 is a precast concrete deck (PCa deck) that has been manufactured in advance in a factory or the like and transported to the site. The new deck 30 has a through hole 35. The new deck 30 is placed on the upper surface of the upper flange 21 so that the stud dowel 25 is inserted into the through hole 35.

[0030] In the illustrated example, the new deck 30 is integrally provided with a plate-shaped deck body 31 and a ground cover 32, but these may be separate. When the deck body 31 and the ground cover 32 are separate, the ground cover 32 may be assembled to the deck body 31 at the site. The new wall balustrade 38 may also be integral with the new deck 30, or may be separate. When the new wall balustrade 38 is separate, the installation of the new wall balustrade 38 may be performed in parallel with the new deck joining process or the paving process described later. The new wall balustrade 38 may be a precast concrete balustrade or a steel balustrade. Note that the present disclosure does not exclude the new wall balustrade 38 being made of cast-in-place concrete.

[0031] Next, in step S140, as shown in Fig. 2(D), non-shrink mortar M is filled into the through-holes 35 to join the new deck 30 to the main girder 20. In addition, joint concrete C is poured into the horizontal joints J1 extending in the direction perpendicular to the bridge axis X and the vertical joints J2 extending in the bridge axis direction Y to join the new deck 30 to the adjacent deck (new deck joining process).

[0032] Next, in step S150, the top surface of the new deck 30 is paved to make it passable for vehicles (paving process). One cycle of steps S100 to S150 described above is repeated until all of the existing deck 10 remains in the work section D1, thereby completing the renewal work for the half cross-section portion within the work section D1, i.e., the section of the bridge 2 that corresponds to the travel lane L1 side.

[0033] Here, if lane restrictions are continued for a long period of time, the impact on the surrounding traffic environment will be large, especially during the daytime when traffic volume is high. For this reason, for example, on routes with heavy traffic volume, lane restrictions are implemented during the nighttime when traffic volume is low, and in many cases, the section where the new deck 30 is installed and the section of the existing deck 10 adjacent to the new deck 30 are opened to traffic during the daytime when traffic volume is high.

[0034] FIG. 4 is a schematic diagram illustrating a general deck replacement method that alternates between daytime traffic-opening periods and nighttime traffic-restricted periods. The bridge 2 is, for example, a two-lane road bridge with a driving lane L1 and an overtaking lane L2, and a shoulder S1 is provided at the end of the driving lane L1 side in the direction perpendicular to the bridge axis X. In the renewal work of such a bridge 2, there is space on the shoulder S1 side. For this reason, during the daytime traffic-opening periods, as shown in FIG. 4(A), the two lanes L1 and L2 are opened to traffic, and a temporary guard fence 5 is installed near the boundary between the shoulder S1 and the driving lane L1, making the area on the shoulder S1 side a fixed restriction zone F. A deck lifting device CR and the like are kept waiting in the fixed restriction zone F. On the other hand, during nighttime traffic restriction times, as shown in Figure 4(B), the temporary protective fence 5 is moved toward the passing lane L2 to expand the work zone FW (i.e., the restricted zone), and only the passing lane L2 is opened, thereby replacing the existing deck 10 on the driving lane L1 and shoulder S1 side.

[0035] In this type of deck replacement method, it is common to not carry out work during daytime traffic opening hours, but only during nighttime traffic restriction hours. Therefore, if the work zone FW is expanded during nighttime traffic restriction hours, and one cycle of work from removing the existing deck to installing the new deck is attempted, there is a risk that the work will not be completed by the time traffic opens during the day.

[0036] In order to ensure that the work is completed before traffic reopens during the day, it is possible to divide one cycle of work into multiple processes and carry out only one process during one traffic restriction period at night, as in the method described in Patent Document 1. However, this method has the problem that the work that can be carried out during one traffic restriction period is limited, which lengthens the construction period.

[0037] Therefore, in the deck replacement method according to this embodiment, not only the traffic control time periods but also the traffic open time periods are effectively used to perform the work efficiently, thereby reducing the number of steps during the traffic control time periods and shortening the construction period. Details of the deck replacement method according to this embodiment are explained below. In the following, construction of the work section D1 on the travel lane L1 and shoulder S1 side, which is a half cross-section part of the bridge 2, is explained. The other work sections D2, D3, D4, etc. are also similar work, so detailed explanations of them are omitted.

[0038] [First embodiment] Fig. 5 is a schematic top view illustrating a deck replacement method according to the first embodiment. As shown in Fig. 5, a bridge 2 has a plurality of (e.g., five) main girders 20 arranged in parallel at a predetermined interval in the direction perpendicular to the bridge axis X. Note that the number of main girders 20 is not limited to five as shown in the illustrated example, and may be four or less, or six or more, depending on the structure of the bridge 2.

[0039] In the following, for convenience, the main girder 20 supporting the end of the existing deck 10 on the passing lane L2 side is referred to as the "first main girder 20G1," and the main girder 20 supporting the end of the existing deck 10 on the road shoulder S1 side is referred to as the "fifth main girder 20G5." In addition, the main girder 20 supporting the approximate center of the existing deck 10 in the direction perpendicular to the bridge axis X is referred to as the "third main girder 20G3," the main girder 20 supporting the gap between the first main girder 20G1 and the third main girder 20G3 of the existing deck 10 is referred to as the "second main girder 20G2," and the main girder 20 supporting the gap between the third main girder 20G3 and the fifth main girder 20G5 of the existing deck 10 is referred to as the "fourth main girder 20G4."

[0040] As shown in FIG. 5, first, a fixed work zone F1 for carrying out work during both the night traffic control hours and the daytime traffic open hours is set on the bridge 2, and an expanded work zone F2 for carrying out work by expanding it during the night traffic control hours is set. The fixed work zone F1 is a work zone for carrying out work while opening not only the passing lane L2 but also the driving lane L1 to traffic. The fixed work zone F1 is set in an area extending from the wall parapet 11 to the vicinity of the boundary X1 between the driving lane L1 and the road shoulder S1. The expanded work zone F2 is a work zone for carrying out work while restricting traffic on the driving lane L1. The expanded work zone F2 is set in an area extending from the vicinity of the boundary X1 between the driving lane L1 and the road shoulder S1 to the vicinity of the boundary X2 between the driving lane L1 and the passing lane L2.

[0041] The fixed work zone F1 is an example of a "first work zone" of the present disclosure, and the extended work zone F2 is an example of a "second work zone" of the present disclosure.

[0042] In this embodiment, two rows of existing deck slab pieces 10A are formed in the direction perpendicular to the bridge axis X. Hereinafter, the existing deck slab piece 10A on the shoulder S1 side is referred to as the "outer existing deck slab piece 10A1," and the existing deck slab piece 10A on the travel lane L1 side is referred to as the "inner existing deck slab piece 10A2." The outer existing deck slab piece 10A1 is an example of the "first existing deck slab piece" of the present disclosure, and the inner existing deck slab piece 10A2 is an example of the "second existing deck slab piece" of the present disclosure.

[0043] Although details will be described later, in this embodiment, the outer existing deck piece 10A1 is removed during nighttime traffic control periods, and a new deck will not be installed in the location from which the outer existing deck piece 10A1 was removed until the next traffic control period. For this reason, to allow vehicles to pass through the driving lane L1 during daytime traffic opening periods, the length LX1 of the outer existing deck piece 10A1 in the direction perpendicular to the bridge axis X is set to be shorter than the length LF of the fixed work zone F1 in the direction perpendicular to the bridge axis X (LX1 <LF)。

[0044] In this embodiment, pre-installation processing is performed on the fifth main girder 20G5 during daytime traffic opening hours. Therefore, in a state where the outer existing deck slab piece 10A1 is removed, the length LX1 of the outer existing deck slab piece 10A1 in the direction perpendicular to the bridge axis X is set longer than the length LG from the end of the existing deck slab 10 on the road shoulder S1 side to the fifth main girder 20G5 (LX1>LG). The length YL of the outer existing deck slab piece 10A1 in the bridge axis direction Y is not particularly limited, but it is desirable that the outer existing deck slab piece 10A1 be a length that allows the outer existing deck slab piece 10A1 to be transported by a vehicle after the outer existing deck slab piece 10A1 is removed.

[0045] The length LX2 of the inner existing deck slab piece 10A2 in the direction perpendicular to the bridge axis X is set as the length from the end of the outer existing deck slab piece 10A1 on the driving lane L1 side to approximately the middle of the bridge 2 in the direction perpendicular to the bridge axis Y. The length LX2 of the inner existing deck slab piece 10A2 in the direction perpendicular to the bridge axis X may be set to a length that exposes at least the upper flange 21 of the fourth main girder 20G4 when the inner existing deck slab piece 10A2 is removed. The length YL of the inner existing deck slab piece 10A2 in the bridge axis direction Y may be the same length as the outer existing deck slab piece 10A1.

[0046] In this embodiment, during the nighttime traffic restriction period, the deck lifting device is used to remove the outer existing deck piece 10A1 and the inner existing deck piece 10A2. During the daytime traffic opening period, if the deck lifting device is a gantry crane, it is made to wait in the fixed work zone F1, and if the deck lifting device is a mobile rough terrain crane or the like, it is made to exit the fixed work zone F1 as necessary, or made to wait in the fixed work zone F1. If the deck lifting device is made to exit the fixed work zone F1 during the traffic opening period, it is made to re-enter during the next traffic restriction period. Below, the deck replacement method according to the first embodiment will be explained, starting with the work during the daytime traffic opening period.

[0047] Fig. 6 is a schematic top view illustrating the work performed during daytime traffic opening hours of the deck replacement method according to the first embodiment. Fig. 7 is a cross-sectional view taken along line AA in Fig. 6. In the following, the work performed during daytime traffic opening hours will be referred to as "daytime work." Daytime work is an example of the "open time work" of the present disclosure.

[0048] As shown in Figures 6 and 7, daytime work is carried out within a fixed work zone F1. The fixed work zone F1 is an area where work is also carried out during the nighttime traffic control hours described below. Before the daytime traffic opening began, the outer existing deck slab piece 10A1 (the subsequent outer existing deck slab piece 10A1' is shown in Figure 10) had already been removed, and the upper flange 21 of the fifth main girder 20G5 is exposed at the removal location X1 where the outer existing deck slab piece 10A1 was removed. This is because the outer existing deck slab piece 10A1 was removed in advance during work during the nighttime traffic control hours described below (later nighttime work).

[0049] During the daytime work, pre-installation treatment is performed on the upper flange 21 of the fifth main girder 20G5 exposed at the removal location X1. As explained based on Figures 2 and 3, the pre-installation treatment includes scraping work to remove remaining concrete and existing stud dowels on the upper surface of the upper flange 21, stud dowel installation work to weld stud dowels 25 onto the upper surface of the upper flange 21 by welding or the like, and rust prevention treatment to apply rust prevention paint or the like to the upper surface of the upper flange 21.

[0050] In this way, by removing the existing outer deck piece 10A1 in advance during the nighttime traffic restriction period and effectively utilizing the daytime traffic open period to perform pre-installation processing on the upper flange 21 of the fifth main girder 20G5, it is possible to reliably reduce the number of processes to be performed during the next nighttime traffic restriction period.

[0051] Next, the work carried out during the nighttime traffic restriction period of the deck replacement method according to the first embodiment will be described. In this embodiment, the work carried out during the nighttime traffic restriction period includes first half work and second half work. Hereinafter, work carried out during the first half of the traffic restriction period will be referred to as "first half night work," and work carried out during the second half of the traffic restriction period will be referred to as "second half night work." The first half night work and the second half night work are examples of "restricted work" in this disclosure.

[0052] Fig. 8 is a schematic top view illustrating the first half of the nighttime work of the deck replacement method according to the first embodiment. Fig. 9 is a cross-sectional view taken along line AA in Fig. 8.

[0053] As shown in FIG. 8 and FIG. 9, in the first half of the nighttime work, first, the inner existing deck slab piece 10A2 adjacent to the removal location X1 in the direction perpendicular to the bridge axis X is cut, and the cut inner existing deck slab piece 10A2 is removed by a deck slab lifting device (not shown). When the inner existing deck slab piece 10A2 is removed, the upper flange 21 of the fourth main girder 20G4 is exposed at the removal location X2 from which the inner existing deck slab piece 10A2 was removed. Next, pre-installation processing is performed on the upper flange 21 of the fourth main girder 20G4 exposed at the removal location X2. In the first half of the nighttime work, the pre-installation processing of the fifth main girder 20G5 has already been completed by the immediately preceding daytime work. Therefore, in the first half of the nighttime work, it is sufficient to perform pre-installation processing only on the fourth main girder 20G4. In other words, the work can be completed in a shorter time than when pre-installation processing is performed on both the fourth main girder 20G4 and the fifth main girder 20G5.

[0054] Fig. 10 is a schematic top view illustrating the second half of the nighttime work of the deck replacement method according to the first embodiment. Fig. 11 is a cross-sectional view taken along line AA in Fig. 10. Fig. 12 is a cross-sectional view taken along line BB in Fig. 10.

[0055] As shown in FIG. 10 and FIG. 11, in the second half of the night work, the new deck 30 is installed at the removal site X1 and the removal site X2. As described above, the new deck 30 is installed by first using a deck lifting device (not shown) to place the new deck 30 on the upper surface of the upper flange 21 of the fourth main girder 20G4 and the fifth main girder 20G5. Once the new deck 30 is placed, the through holes 35 are filled with non-shrink mortar M, and concrete C is poured into the horizontal and vertical joints to join the new deck 30 to the main girders 20G4, 20G5 and the other decks in the vicinity. Once the new deck 30 is installed, a permanent pavement is constructed on the upper surface of the new deck 30. It is desirable to apply the permanent pavement to the entire surface of the new deck 30, but the permanent pavement may be applied only to the expanded work zone F2, and the fixed work zone F1 may be paved during the next daytime work.

[0056] 10 and 12, in the latter half of the night work, the subsequent outer existing deck slab piece 10A1' adjacent to the removal location X1 in the bridge axis direction Y is cut, and the cut outer existing deck slab piece 10A1' is removed by a deck lifting device (not shown). The outer existing deck slab piece 10A1' may be cut and removed before or after the new deck slab 30 is installed.

[0057] Here, when the outer existing deck piece 10A1' is removed, the end of the succeeding inner existing deck piece 10A2' (the existing deck piece to be cut and removed during the next traffic control period) is supported by the fourth main girder 20G4 as a cantilever, which may cause an unstable state in which the traffic load cannot be supported during the daytime traffic control period. In such a case, as shown in FIG. 12, the inner existing deck piece 10A2' is temporarily supported from below using a temporary support member 50. The temporary support member 50 includes, for example, a cross member 51 made of H-shaped steel or I-shaped steel, a height adjustment member 52 such as a screw jack, and a bridge axis direction member 52' ​​made of H-shaped steel or I-shaped steel. The cross member 51 is spanned between the fourth main girder 20G4 and the fifth main girder 20G5 and between the third main girder 20G3 and the fourth main girder 20G4 in the direction perpendicular to the bridge axis X. The method of fixing the cross member 51 to each of the main girders 20G3, 20G4, 20G5 is not particularly limited, and bolt fastening or the like may be used. The height adjustment member 52 is placed on the upper flange of the cross member 51. The bridge axis direction member 52' ​​is bridged in the bridge axis direction X on the upper part of the height adjustment member 52 so as to support the underside of the inner existing deck slab piece 10A2'. The vertical positional relationship between the height adjustment member 52 and the bridge axis direction member 52' ​​can also be reversed.

[0058] In this embodiment, by thus cutting and removing the subsequent outer existing deck slab piece 10A1' in the latter half of the nighttime work and exposing the fifth main girder 20G5, pre-installation processing can be performed on the upper flange 21 of the fifth main girder 20G5 during daytime work in the next traffic-opening period. In other words, it becomes possible to effectively use the daytime traffic-opening period to carry out work, and to reliably reduce the number of processes in the next traffic-restricted period.

[0059] By repeating the above-mentioned daytime work, early nighttime work, and late nighttime work until the existing deck 10 in the work area D1 is gone, the deck replacement work for the half-section portion within the work area D1, i.e., the portion of one section of the bridge 2 that corresponds to the driving lane L1 side, is completed.

[0060] Next, the flow of daytime work of the deck replacement method according to the first embodiment will be described based on the flow diagram in Fig. 13. For convenience, the description will be given assuming that at the start of the flow shown in Fig. 13, the outer existing deck piece 10A1 has already been removed in the previous nighttime latter half work.

[0061] In step S200, the deck lifting device CR is moved to the fixed work zone F1, and the temporary protective fence 5 is moved to near the boundary between the road shoulder S1 and the driving lane L1, thereby making the driving lane L1 available to vehicles, i.e., opening it to traffic.

[0062] Next, in step S210, pre-installation treatments (surfacing work, stud dowel installation, and rust prevention treatment) are performed on the upper flange 21 of the fifth main girder 20G5 exposed at the removal site X1 where the outer existing deck slab piece 10A1 has been removed.

[0063] Once the pre-installation process is complete, the daytime work ends.

[0064] Next, the flow of the nighttime first half work and the nighttime second half work of the deck replacement method according to the first embodiment will be described with reference to the flow diagram of FIG.

[0065] In step S300, as the first half of the nighttime work, the temporary protective fence 5 is moved to the vicinity of the boundary between the travel lane L1 and the passing lane L2, and the deck lifting device CR is moved (or entered) into the expanded work zone F2, thereby starting traffic control of the travel lane L1. Once the traffic control has started, in step S305, the inner existing deck slab piece 10A2 is cut, and the cut inner existing deck slab piece 10A2 is removed by the deck lifting device CR. Once the inner existing deck slab piece 10A2 has been removed, in step S310, pre-installation treatment (scraping work, stud dowel installation, rust prevention treatment) is performed on the upper flange 21 of the fourth main girder 20G4 exposed at the removal location X2 of the inner existing deck slab piece 10A2, and the first half of the nighttime work is completed.

[0066] In step S320, as the latter half of the nighttime work, the new deck 30 is installed at the removal locations X1, X2 of the outer existing deck piece 10A1 and the inner existing deck piece 10A2. In addition, in step S330, the subsequent outer existing deck piece 10A1' is cut and removed. The steps of step S320 and step S330 can be performed in any order. Note that the construction of step S330 is not necessary if all of the existing decks 10 that are the subject of the renewal work of the bridge 2 have already been removed. In step S340, permanent paving is constructed on the top surface of the installed new deck 30, and the latter half of the nighttime work is completed.

[0067] According to the deck replacement method according to the first embodiment described above in detail, the subsequent outer existing deck piece 10A1' is cut and removed during the latter half of the nighttime work during the traffic control period, and the fifth main girder 20G5 is exposed in advance, so that pre-installation treatment can be performed on the upper flange 21 of the fifth main girder 20G5 during daytime work during the next traffic-open period. In other words, by effectively using not only the traffic-controlled hours at night but also the traffic-open hours during the day to perform work, it is possible to shorten the time required from removing the existing deck 10 to installing the new deck 30, compared to the conventional method in which work is performed only during the traffic control period, and it is also possible to reliably shorten the construction period.

[0068] In addition, by carrying out pre-installation processing on the fifth main girder 20G5 during the daytime traffic opening hours, the number of processes to be performed during the next traffic restriction hours can be effectively reduced, and the risk of not being able to finish the work by the time the traffic is opened the next day, i.e., the risk of not being able to lift the traffic restrictions by the time the traffic is opened, can be reliably reduced. In addition, since the temporary deck used in the construction method described in Patent Document 1 is not required, it is also possible to effectively reduce the time and effort required for installing and removing the temporary deck.

[0069] [Second embodiment] Next, the details of the deck replacement method according to the second embodiment will be described. In the second embodiment, the setting of the fixed work zone F1 and the extended work zone F2, and the setting of the outer existing deck piece 10A1 and the inner existing deck piece 10A2 are the same as those in the first embodiment, so the description thereof will be omitted.

[0070] Fig. 15 is a schematic top view illustrating daytime work of the deck replacement method according to the second embodiment. Fig. 16 is a cross-sectional view taken along line AA in Fig. 15. As shown in Figs. 15 and 16, in the second embodiment, as in the first embodiment, when daytime work is started, the outer existing deck piece 10A1 has already been removed, and the upper flange 21 of the fifth main girder 20G5 is exposed at the removal location X1.

[0071] In the second embodiment, the inner existing deck slab piece 10A2 (the succeeding inner existing deck slab piece 10A2' is shown in FIG. 19) is also removed, but the temporary deck slab 80 was installed in the location where the inner existing deck slab piece 10A2 was removed during the last half of the night work just before. Details of the temporary deck slab 80 will be described later.

[0072] In the daytime work of the second embodiment, similarly to the first embodiment, pre-installation treatment (surface scraping work, stud dowel installation, rust prevention treatment) is performed on the upper flange 21 of the fifth main girder 20G5 exposed at the removal location X1. In this way, the outer existing deck slab piece 10A1 and the inner existing deck slab piece 10A2 are removed in advance during the night traffic control period, and further, a temporary deck slab 80 is installed at the removal location X2 of the inner existing deck slab piece 10A2, so that the upper flange 21 of the fifth main girder 20G5 can be pre-installed while opening the travel lane L1 to traffic. This makes it possible to reliably reduce the number of processes to be performed during the next night traffic control period.

[0073] Fig. 17 is a schematic top view illustrating the first half of the nighttime work of the deck replacement method according to the second embodiment. Fig. 18 is a cross-sectional view taken along the line AA in Fig. 17.

[0074] As shown in Figures 17 and 18, in the first half of the nighttime work in the second embodiment, first, the temporary deck 80 is removed by a deck lifting device (not shown). When the temporary deck 80 is removed, the fourth main girder 20G4 is exposed at the removal location X2. Although details will be described later, the upper flange 21 of the fourth main girder 20G4 exposed at the removal location X2 has already been subjected to pre-installation treatment (scraping work, stud dowel installation, and rust prevention treatment) in the second half of the nighttime work on the previous day. Therefore, in the first half of the nighttime work in the second embodiment, after the temporary deck 80 is removed, the new deck 30 is installed at the removal locations X1 and X2.

[0075] That is, the nighttime first half work can be completed in a short time compared to the first embodiment in which pre-installation processing is performed on the fourth main girder 20G4 during the nighttime first half work. Note that the main paving of the upper surface of the new deck 30 may be performed during the nighttime first half work after the new deck 30 is installed, or may be performed in parallel with other work during the nighttime second half work.

[0076] Fig. 19 is a schematic top view illustrating the second half of the nighttime work of the deck replacement method according to the second embodiment. Fig. 20 is a cross-sectional view taken along line AA in Fig. 19. Fig. 21 is a schematic cross-sectional view showing the state in which the temporary deck 80 has been installed in Fig. 20.

[0077] As shown in Figures 19 and 20, in the second half of the nighttime work in the second embodiment, first, the subsequent outer existing deck slab piece 10A1' and inner existing deck slab piece 10A2' are cut and removed. For convenience, the outer existing deck slab piece 10A1' and the inner existing deck slab piece 10A2' are shown as separate existing deck slab pieces, but they can be cut and removed as a single existing deck slab piece. The outer existing deck slab piece 10A1' and the inner existing deck slab piece 10A2' can be removed using a deck lifting device (not shown).

[0078] 19 and 20, in the second half of the nighttime work in the second embodiment, pre-installation treatment (scraping work, stud dowel installation, rust prevention treatment) is performed on the upper flange 21 of the fourth main girder 20G4 exposed at the removal location X2' where the inner existing deck slab piece 10A2' has been removed. This makes it possible to install the new deck slab 30 without performing pre-installation treatment after removing the temporary deck slab 80 in the first half of the nighttime work on the following day. Pre-installation treatment is performed on the fifth main girder 20G5 exposed at the removal location X1' where the outer existing deck slab piece 10A1' has been removed in the next daytime work.

[0079] When the pre-installation process of the fourth main girder 20G4 is completed, as shown in FIG. 21, a temporary deck 80 is installed at the removal site X2' using a deck lifting device (not shown). The temporary deck 80 has, for example, a rectangular lining plate 81 made by integrating H-shaped steel materials or steel plates by welding or the like, and a temporary pavement 82 provided on the upper surface of the lining plate 81. The temporary deck 80 may be fixed to the surrounding decks by bolt fastening or the like. If the temporary deck 80 is unstable after installation, the temporary support member 50 may be used to stably support the temporary deck 80 from below, as in the first embodiment. Once the temporary deck 80 is installed, the latter half of the night work is completed.

[0080] By repeating the above-mentioned daytime work, early nighttime work, and late nighttime work until the existing deck 10 in the work area D1 is gone, the deck replacement work for the half-section portion within the work area D1, i.e., the portion of one section of the bridge 2 that corresponds to the driving lane L1 side, is completed.

[0081] Next, the flow of the first half of the nighttime work and the second half of the nighttime work of the deck replacement method according to the second embodiment will be described based on the flow diagram in Fig. 22. Note that the daytime work of the deck replacement method according to the second embodiment has the same flow as the daytime work of the first embodiment shown in Fig. 13, except that the temporary deck 80 is installed and performed, so the description will be omitted.

[0082] In step S400, as the first half of the night work, the temporary guardrail 5 is moved to the vicinity of the boundary between the travel lane L1 and the passing lane L2, and the deck lifting device CR is moved (or entered) into the expanded work zone F2, thereby starting traffic control of the travel lane L1. Once traffic control has started, in step S405, the temporary deck 80 installed at the removal location X2 of the inner existing deck piece 10A2 is removed using the deck lifting device CR. The upper flange 21 of the fourth main girder 20G4 exposed at the removal location X2 of the temporary deck 80 (inner existing deck piece 10A2) has been subjected to pre-installation treatment (scraping work, stud dowel installation, rust prevention treatment) in the second half of the night work on the previous day, and the upper flange 21 of the fifth main girder 20G5 exposed at the removal location X1 of the outer existing deck piece 10A1 has been subjected to pre-installation treatment in the daytime work just before.

[0083] For this reason, in the next step S410, the deck lifting device CR is used to install the new deck 30 at the removal locations X1 and X2 of the outer existing deck piece 10A1 and the temporary deck 80 (inner existing deck piece 10A2). Next, in step S420, a permanent pavement is constructed on the top surface of the new deck 30, completing the first half of the nighttime work. Note that the permanent pavement may be performed in parallel with the second half of the nighttime work.

[0084] In step S430, as the latter half of the nighttime work, the subsequent outer existing deck slab piece 10A1' and the inner existing deck slab piece 10A2' are cut and removed either together or separately. Next, in step S440, pre-installation treatment (scraping work, stud dowel installation, rust prevention treatment) is performed on the upper flange 21 of the fourth main girder 20G4 exposed at the removal location X2' from which the inner existing deck slab piece 10A2' has been removed. After the pre-installation treatment is performed, in step S450, the deck lifting device CR is used to install the temporary deck slab 80 at the removal location X2', and the latter half of the nighttime work is completed.

[0085] According to the deck replacement method according to the second embodiment described above, the subsequent outer existing deck piece 10A1' and the inner existing deck piece 10A2' are cut and removed as a unit or separately during the latter half of the nighttime work during the traffic control period. By installing a temporary deck 80 at the removal location X2' of the inner existing deck piece 10A2', the traffic lane L1 can be opened to traffic during the next traffic opening period, while the fifth main girder 20G5 is exposed in advance at the removal location X1' of the outer existing deck piece 10A1', so that pre-installation treatment can be performed on the upper flange 21 of the fifth main girder 20G5 during daytime work during the next traffic opening period. In other words, by effectively using not only the traffic control period at night but also the traffic opening period during the daytime to perform work, the time required from the removal of the existing deck 10 to the installation of the new deck 30 can be shortened compared to the conventional method in which work is performed only during the traffic control period, and the construction period can also be reliably shortened.

[0086] In addition, by carrying out pre-installation processing on the fifth main girder 20G5 during daytime traffic opening hours, the number of processes to be performed during the next traffic restriction period can be effectively reduced, and the risk of not being able to complete the work by the time traffic is opened the next day, in other words, the risk of not being able to lift the traffic restrictions by the time traffic is opened, can be reliably reduced.

[0087] In addition, by carrying out pre-installation treatment on the fourth main girder 20G4 exposed at the removal site X2' from which the inner existing deck piece 10A2' was removed during the latter half of the nighttime work during the traffic control period on the previous day, the new deck 30 can be installed during the first half of the nighttime work during the traffic control period on the next day by simply removing the temporary deck 80. In other words, the first half of the nighttime work can be completed earlier than in the first embodiment in which the new deck 30 is installed after carrying out pre-installation treatment on the fourth main girder 20G4 during the first half of the nighttime work. As a result, even if the second half of the nighttime work cannot be performed due to some kind of trouble, it is possible to open the road to traffic the next day by completing only the first half of the nighttime work.

[0088] [others] The present disclosure is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present disclosure.

[0089] For example, in the first and second embodiments, it has been described that the fifth main girder 20G5 is exposed at the removal location X1 of the outer existing deck piece 10A1, but as shown in Figure 23, the outer existing deck piece 10A1 may be lengthened in the direction perpendicular to the bridge axis X so that the fourth main girder 20G4 is also exposed at the removal location X1.

[0090] With this configuration, in both the first and second embodiments, pre-installation treatment (surfacing work, stud dowel installation, rust prevention treatment) for the fourth main girder 20G4 can be performed during daytime work. That is, in the first embodiment, pre-installation treatment performed in the first half of the nighttime work (step S310 in FIG. 14) can be omitted, and in the second embodiment, pre-installation treatment performed in the second half of the nighttime work (step S440 in FIG. 22) can be omitted, making it possible to more reliably complete nighttime work. Although not shown in FIG. 23, if the inner existing deck slab piece 10A2 (or the temporary deck slab 80) becomes unstable, it is desirable to temporarily support it using the above-mentioned temporary support member 50.

[0091] Further, the existing deck pieces 10A1, 10A2 have been described as being formed in two rows, but they may be formed in three or more rows depending on the length of the bridge 2 in the width direction and the number of lanes.

[0092] Furthermore, while the fixed work zone F1 has been described as being set on the end side (shoulder S1 side) of the bridge 2, this disclosure can also be applied to so-called island regulations, in which the fixed work zone F1 is set on the center side of the bridge 2 in the width direction, and vehicles are allowed to pass on both ends of the bridge 2. This disclosure can also be widely applied to deck renewal work for bridges other than road bridges. [Explanation of symbols]

[0093] 1,2,3...Bridge, 5...Temporary guardrail, 6...Work zone, 7...Traffic lane, 10...Existing deck, 10A...Existing deck piece, 10A1...Outer existing deck piece (first existing deck piece), 10A2...Inner existing deck piece (second existing deck piece), 11...Wall parapet, 20...Main girder, 20G1...First main girder, 20G2...Second main girder, 20G3...Third main girder, 20G4...Fourth main girder, 20G5...Fifth main girder, 21...Upper flange, 22... Web, 23...Lower flange, 25...Stud dowel, 30...New deck, 31...Deck body, 32...Ground cover, 35...Through hole, 38...New wall railing, 50...Temporary support member, 51...Horizontal member, 52...Height adjustment member, 52'...Bridge axis direction member, 80...Temporary deck, 81...Covering plate, 82...Temporary pavement, X1...Removal area (first removal area), X2...Removal area (second removal area), F1...Fixed work zone (first work zone), F2...Expanded work zone F2 (second work zone)

Claims

1. A deck replacement method in which an existing deck installed on a plurality of main girders arranged in parallel at a predetermined interval in a direction perpendicular to the bridge axis of a bridge is replaced with a new deck by alternately repeating opening work performed during traffic opening hours when at least some or all of the lanes are open and traffic restriction work performed during traffic restriction hours when some of the lanes are restricted, During the traffic opening time period, the opening work is carried out in a first work zone that is set in an area of ​​the bridge that does not include an area where vehicles are allowed to pass, During the traffic regulation time period, in addition to the first work zone, the regulation work is carried out in a second work zone that is set by extending the first work zone to an area on the lane side to be regulated, The regulated work includes a first cutting and removal process in which at least a portion of the existing deck slab located within the first work zone is cut to form a first existing deck slab piece, and the first existing deck slab piece is removed to expose at least one or more main girders among the multiple main girders at a first removal location, which is a location where the first existing deck slab piece has been removed; The opening work includes a pre-installation processing step of performing pre-installation processing that needs to be performed before installing the new deck slab on the main girder exposed at the first removal location, The regulation work further includes a new deck installation process of installing the new deck at the first removal location where the main girder to which the pre-installation treatment has been performed is exposed. Deck replacement method.

2. The deck replacement method according to claim 1, The pre-installation treatment includes at least one of the following operations: scraping the upper flange of the main girder, installing stud dowels, and applying an anti-rust paint to the upper flange. Deck replacement method.

3. The deck replacement method according to claim 1 or 2, The regulated work further includes a second cutting and removal process for cutting an existing deck slab adjacent to the first removal location where the main girder on which the pre-installation treatment was performed is exposed in a direction perpendicular to the bridge axis, at least a portion of which is located within the second work zone, to form a second existing deck slab piece, and removing the second existing deck slab piece; In the new deck installation step, the new deck is installed at the first removal location and at a second removal location where the second existing deck piece was removed. Deck replacement method.

4. The deck replacement method according to claim 3, In the case where at least one main girder is exposed at the second removal location due to the removal of the second existing deck piece during the regulation work, the new deck is installed after the pre-installation treatment is performed on the main girder. Deck replacement method.

5. The deck replacement method according to claim 3, A temporary support member is installed to temporarily support the existing deck slab from below, the existing deck slab corresponding to the portion where the second existing deck slab piece is to be formed, from the period between the removal of the first existing deck slab piece and the formation of the second existing deck slab piece. Deck replacement method.

6. The deck replacement method according to claim 1 or 2, The regulation work is as follows: a second cutting and removal process in which, in addition to the first existing deck piece, an existing deck adjacent to the first existing deck piece in the direction perpendicular to the bridge axis, at least a portion of which is located within the second work zone, is cut to form a second existing deck piece integrally or separately from the first existing deck piece, and the first existing deck piece and the second existing deck piece are removed integrally or separately; The method further includes a temporary deck installation process of installing a temporary deck that does not cover the upper part of the main girder exposed at the first removal location at a second removal location where the second existing deck piece has been removed, before starting the opening work, In the new deck installation step, after removing the temporary deck, the new deck is installed at the first removal location and the second removal location. Deck replacement method.

7. The deck replacement method according to claim 6, In the case where at least one main girder is exposed at the second removal location due to the removal of the second existing deck piece during the restricted work, the temporary deck is installed after the pre-installation treatment is performed on the main girder. Deck replacement method.

8. The deck replacement method according to claim 6, After the temporary floor slab is installed, a temporary support member is installed to temporarily support the temporary floor slab from below until the temporary floor slab is removed. Deck replacement method.

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