Method of replacing existing concrete floor slab and road bridge

Abstract

To provide a replacing method of an existing concrete floor slab and a road bridge capable of replacing the floor slab while partially using the road bridge having a wide width, and capable of imparting long-term durability to the road bridge including a new concrete floor slab.SOLUTION: The replacement method of the existing concrete floor slab 10 includes a floor slab replacement step of repeating an existing floor slab removal step and a new floor slab installation step to replace the existing concrete floor slab 10 in a plurality of replacement sections S divided in the width direction X with a plurality of new precast concrete floor slab segments 20 arranged in the width direction X, a joint construction step of constructing a vertical joint M of an RC structure between the new precast concrete floor slab segments 20 adjacent to each other in the width direction X, and a tension step of introducing prestress into the new precast concrete floor slab segments 20 arranged in the width direction X from one side end to the other side end in the width direction X after the joint construction step.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a method for replacing an existing concrete deck slab and a road bridge. [Background technology]

[0002] In general, the concrete decks of road bridges, such as steel girder bridges, are structural components that directly support vehicles, and are directly affected by the increase in vehicle traffic volume and the increasing size of vehicles. As a result, there have been many cases of damage requiring reconstruction. Concrete decks are also affected by the spraying of antifreeze in cold regions and by salt airborne from the ocean in coastal areas. As a result, there have been many cases of salt damage and deterioration due to corrosion of the steel within the concrete.

[0003] Many repair methods have been developed to address the damage and deterioration of concrete slabs described above, but a fundamental solution is to replace the concrete slab. Methods for replacing concrete slabs include removing the existing slab, assembling formwork and rebar, and pouring concrete on-site to construct a new reinforced concrete slab, and removing the existing slab and then installing a new precast prestressed concrete slab in its place. These methods simultaneously replace the existing slab across the entire width of the road, which means the entire width of the road is unusable during the construction period, necessitating road closures and potentially worsening traffic conditions around the road.

[0004] One concrete deck replacement method that can solve the above-mentioned problems is to divide the concrete deck into a primary construction section and a secondary construction section in the width direction of the road, and carry out replacement work on the primary construction section while continuing to use the secondary construction section as a road.After replacement of the primary construction section is completed, the primary construction section is put into use as a road, and then replacement work on the secondary construction section is carried out (for example, Patent Document 1).

[0005] However, conventional concrete deck replacement methods were not designed to replace the concrete decks of wide road bridges with three or more lanes. Therefore, there was room for further consideration in order to ensure long-term durability while implementing concrete deck replacement methods on such wide road bridges while keeping some of them in service. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-151768 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide a method for replacing an existing concrete deck and a road bridge that allows the deck to be replaced while part of the widened road bridge remains in service, and that can provide long-term durability to the road bridge, including the newly constructed concrete deck. [Means for solving the problem]

[0008] (1) A road bridge deck replacement method according to one embodiment of the present invention includes: a first existing deck removal process for setting a plurality of replacement sections divided in the width direction in the replacement area of ​​the existing concrete deck; removing a first existing concrete deck in a first replacement section among the plurality of replacement sections; a first new deck laying process for laying a first new precast concrete deck segment in the first replacement section after the first existing deck removal process; an existing deck removal process for removing an existing concrete deck in a second replacement section that is another part of the replacement area; and a new deck laying process for laying a new precast concrete deck segment in the second replacement section after the existing deck removal process. The method includes a slab replacement process in which the existing slab removal process and the new slab laying process are repeated to replace the existing concrete slabs in the multiple replacement sections divided in the width direction with multiple new precast concrete slab segments lined up in the width direction; a joint construction process in which vertical joints of an RC structure are constructed between the new precast concrete slab segments adjacent in the width direction in the multiple replacement sections divided in the width direction; and a tensioning process in which, after the joint construction process, prestress is introduced into the new precast concrete slab segments lined up in the width direction by PC steel members inserted from one side end to the other side end in the width direction. (2) In the above (1), after the joint construction process and before the tensioning process, the newly constructed precast concrete slab segments adjacent in the width direction may be put into service. (3) A road bridge according to one embodiment of the present invention comprises an existing girder and a concrete deck supported by the existing girder, the concrete deck having a plurality of newly constructed precast concrete deck segments divided in the width direction and vertical joints of an RC structure formed between adjacent newly constructed precast concrete deck segments in the width direction, and prestress is introduced into the concrete deck from one end to the other end in the width direction. (4) In the above (3), the newly constructed precast concrete slab segment may be of reinforced concrete structure. (5) In the above (3), the newly constructed precast concrete slab segment may be a PC structure. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for replacing an existing concrete deck and a road bridge that can carry out deck replacement while keeping part of the widened road bridge in service, and that can provide long-term durability to the road bridge including the newly constructed concrete deck. In addition, prestressing is easy to introduce, and there are no cost issues as only the minimum necessary anchors and anchoring sections are required. Furthermore, the high degree of freedom in the construction order allows for regulation plans that suit the conditions of the construction site, minimizing social losses. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view illustrating the replacement area and replacement section of a road bridge. [Figure 2] FIG. 2 is an enlarged plan view of a newly constructed precast concrete slab segment in part A of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view taken along the arrow B in FIG. 2. [Figure 4] This figure explains the relationship between replacement sections under construction and lane restrictions, where (1) shows the lane restrictions under construction for the first and second replacement sections, (2) shows the lane restrictions under construction for the second replacement section, and (3) shows the lane restrictions under construction for the third replacement section. [Figure 5] This is a diagram explaining the replacement work of the existing concrete deck in the first replacement section. [Figure 6] This is a diagram explaining the replacement work of the existing concrete deck in the second replacement section. [Figure 7] This is a diagram explaining the replacement work and tensioning process of the existing concrete deck in the third replacement section. [Figure 8] This is a diagram explaining a road bridge that has been replaced with a new concrete deck after the tensioning process. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Embodiment) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Figure 1 is a plan view illustrating replacement areas P and S in a road bridge 200. Figure 2 is an enlarged plan view of new precast concrete deck segments 20 aligned in the width direction X in part A of Figure 1. Figure 3 is a cross-sectional view taken along arrow B in Figure 2. Note that, hereinafter, parts having common functions may be given the same reference numerals or symbols.

[0012] As shown in FIG. 1 or FIG. 8, a road bridge 200 according to the embodiment is an existing road bridge 100 in which the existing bridge girders (hereinafter referred to as existing girders 30) remain intact, and the existing concrete deck slab (hereinafter referred to as existing concrete deck 10; see FIG. 5(a)) is replaced with a new concrete deck slab (hereinafter referred to as new concrete deck 2; see FIG. 8). The road bridge 200 may be one in which part or all of the existing concrete deck slab 10 has been replaced with the new concrete deck slab 2 in the width direction X. The road bridge 200 or the existing road bridge 100 may have a mixed structure or a composite structure in which a concrete deck slab is supported or integrated on top of existing girders 30 such as steel girders. The road bridge 200 or the existing road bridge 100 may also have a structure in which a concrete deck slab is supported or integrated on top of concrete girders. Roads including pavement and road incidental structures are installed on the concrete deck slab.

[0013] The existing girder 30 is supported by a bridge pier (not shown). The existing girder 30 extends along the bridge axis direction Y. There may be multiple existing girders 30. As shown in Figures 5 to 8, for example, six existing girders 30 may be arranged parallel to each other for a width of three lanes on each side. Here, for example, two adjacent existing girders 30 may support one new precast concrete deck segment 20. One new precast concrete deck segment 20 may be supported by two or more existing girders 30.

[0014] As shown in Figures 2, 3, or 8, the deck of the road bridge 200 has a plurality of newly constructed precast concrete deck segments 20 arranged in the width direction X in place of the existing concrete deck 10. Due to transportation constraints, the dimension of the newly constructed precast concrete deck segments 20 in the bridge axis direction Y is generally limited to about 2.0 m. The deck of the road bridge 200 is divided into three or more sections (for example, three) in the width direction X, including a first replacement section S1 in which a first existing concrete deck 11 (a portion of the existing concrete deck 10 corresponding to the first replacement section S1) will be replaced first with a first new deck 21, a second replacement section S2 in which a second existing concrete deck 12 (a portion of the existing concrete deck 10 corresponding to the second replacement section S2) will be replaced with a second new deck 22, and a third replacement section S3 in which a third existing deck 13 (a portion of the existing concrete deck 10 corresponding to the third replacement section S3) will be replaced with a third new deck 23. The deck of the road bridge 200 is configured such that, instead of the existing concrete deck 10, new precast concrete deck segments 20 are also lined up in the bridge axis direction Y in correspondence with the replacement sections S divided in the replacement area P in the bridge axis direction Y.

[0015] Between the new slabs installed in adjacent sections in the width direction X, a vertical joint M made of reinforced concrete is formed by filling the joints with concrete or a cement-based filler such as mortar. Specifically, as shown in FIGS. 2, 3, 6(f), and 8, adjacent new precast concrete slab segments 20 are joined by a vertical joint M formed by filling and hardening concrete or a cement-based filler such as mortar in the gap between the adjacent new precast concrete slab segments 20 with joints (not shown), such as lap joints, loop reinforcing bars, Head-bars (registered trademark), etc., embedded and fixed in the new slab segments 20. Similar to the joints between the new precast concrete slab segments 20 adjacent in the width direction X, horizontal joints (not shown) made of reinforced concrete are also formed between the new precast concrete slab segments 20 adjacent in the bridge axis direction Y by filling the gap with concrete with embedded joints.

[0016] As described above, the road bridge 200 includes an existing girder 30 and a concrete deck supported by the existing girder 30. The concrete deck has a plurality of new precast concrete deck segments 20 divided in the width direction X, and vertical joints M of a reinforced concrete structure (reinforced concrete structure) formed between adjacent new precast concrete deck segments 20 in the width direction X. The vertical joints M may extend along the bridge axis direction Y. Here, prestress is ultimately introduced into the concrete deck from one end to the other end in the width direction X. In this way, because the vertical joints M of the reinforced concrete structure are temporarily formed between adjacent new precast concrete deck segments 20 in the width direction X, sufficient bearing capacity can be ensured in the short term even when the replacement of a portion of the concrete deck in the width direction X is incomplete and prestressing has not yet been introduced to the concrete deck. This allows construction restrictions to be lifted in the replacement section including the adjacent new precast concrete deck segments 20, allowing vehicles and the like to pass through and use the bridge. Furthermore, since prestress is introduced into the concrete slab from one end to the other in the width direction X of the new precast concrete slab segments 20 arranged in the width direction X, including the vertical joints M, sufficient bearing strength can be ensured over the long term. Therefore, according to the road bridge 200, the concrete slab can be replaced while part of the widened road bridge is in service, and the road bridge 200 including the new concrete slab 2 can be endowed with long-term durability.

[0017] The existing concrete slab 10 has deteriorated in performance, including strength, due to fatigue damage, corrosion, deterioration, etc. caused by the action of repeated traffic loads (live loads) and aging. The existing concrete slab 10 may have cracks in the concrete cover due to expansion pressure caused by rust on the embedded rebar, and may even spall the concrete. Therefore, the existing concrete slab 10 may have a small cover, cracks in the cover, or exposed rebar.

[0018] The new precast concrete slab segments 20 that make up the new concrete slab 2 may be reinforced concrete segments (precast RC slab segments) that are manufactured (precast) to predetermined dimensions in a factory and transported to the site. The new precast concrete slab segments 20 that make up the new concrete slab 2 may be prestressed concrete slab segments (precast PC slab segments) that are manufactured (precast, pretensioned) to predetermined dimensions in a factory and transported to the site.

[0019] The new precast concrete slab segments 20 may be of reinforced concrete structure (reinforced concrete structure). When the new precast concrete slab segments 20 constituting the new concrete slab 2 are precast RC slab segments and the vertical joints M are of reinforced concrete structure, the new concrete slab 2 can be made into a structure with sufficient short-term bearing strength during provisional use (a short, temporary period until completion of construction, during which vehicles are allowed to pass over the new precast concrete slab segments 20). Then, by introducing appropriate prestress across the entire width in the width direction X at the end of the provisional use period, the structure can be made to have sufficient long-term bearing strength.

[0020] The new precast concrete slab segments 20 may be PC structures (prestressed concrete structures). When the new precast concrete slab segments 20 are precast PC slab segments and the vertical joints M are reinforced concrete structures, a certain amount of prestress has already been introduced into the precast PC slab segments during the provisional service period, allowing the new concrete slab 2 to have sufficient short-term strength and suppress cracking. Then, by introducing appropriate prestress across the entire width in the width direction X at the end of the provisional service period, it can be made to have sufficient long-term strength and can also be made into a rationally designed structure by carefully controlling the amount of prestress in the precast PC slab segments and the vertical joints M.

[0021] As shown in FIG. 2, the new precast concrete slab segment 20 is a block with a parallelogram shape (including a rectangular shape) in plan view, having short and long sides and a predetermined plate thickness. When applied to a bridge with an oblique angle, the shape of the new precast concrete slab segment 20 in plan view may be a parallelogram shape with a slope corresponding to the oblique angle. The new precast concrete slab segment 20 is placed on the existing girder 30 with its short side aligned with the bridge axis direction Y and its long side aligned with the width direction X. The new precast concrete slab segment 20 is provided with a joint on its short side, one end of which is embedded and fixed inside the new concrete slab 2, and the other end of which is exposed in the gap between adjacent new precast concrete slab segments 20 in the width direction X and is embedded and fixed in the vertical joint M formed by the concrete filled in the gap. The newly constructed precast concrete deck segments 20 are provided with joints on the long sides, as appropriate, with one end embedded and fixed inside the newly constructed concrete deck slab 2 and the other end exposed in the gap between adjacent newly constructed precast concrete deck segments 20 in the bridge axis direction Y, and embedded and fixed in the horizontal joints formed by the cement-based filler such as concrete or mortar filled in the gap.

[0022] As shown in Figure 8, a sheath 70 that forms a cavity for inserting the PC steel members 60 on-site is embedded in the new precast concrete slab segment 20. The new precast concrete slab segment 20 has spaces 80 formed at its side ends to accommodate fixing devices 90 for securing the PC steel members 60 inserted on-site.

[0023] The new precast concrete slab segment 20 has inserts on its upper or lower surface as appropriate for connecting road ancillary structures, etc. The new precast concrete slab segment 20 has dowel holes as appropriate for inserting stud dowels provided on the existing girders 30 to connect them. The new precast concrete slab segment 20 has height adjustment bolts as appropriate for adjusting its position relative to the existing girders 30. The new precast concrete slab segment 20 has lifting hardware as appropriate for allowing it to be moved while lifted with a lifting wire, etc.

[0024] (Road bridge deck replacement method) The replacement method for an existing concrete deck 10 according to this embodiment will be described below using an example in which the existing concrete deck 10 of an existing road bridge 100, which has three lanes on each side (such as the three down lanes of a total of six lanes, three up lanes and three down lanes), is divided into three sections in the width direction X and replaced as shown in FIG. 4. FIG. 4 is a diagram illustrating the relationship between the replacement section S during construction and lane restrictions. (1) in FIG. 4 shows the lane restrictions during construction for the first replacement section S1 and the second replacement section S2. (2) in FIG. 4 shows the lane restrictions during construction for the second replacement section S2. (3) in FIG. 4 shows the lane restrictions during construction for the third replacement section S3. FIG. 5 is a diagram illustrating the replacement work for the existing concrete deck 10 in the first replacement section S1. FIG. 5(a) shows the condition of the existing concrete deck 10 before replacement. FIG. 5(b) shows the removal of the first existing concrete slab 11. FIG. 5(c) shows the erection of the first new precast concrete slab segment 21. FIG. 6 is a diagram illustrating the replacement work of the existing concrete slab 10 in the second replacement section S2. FIG. 6(d) shows the removal of the second existing concrete slab 12. FIG. 6(e) shows the erection of the second new precast concrete slab segment 22. FIG. 6(f) shows the construction of the vertical joint M. FIG. 7 is a diagram illustrating the replacement work of the existing concrete slab 10 in the third replacement section S3. FIG. 7(g) shows the removal of the third existing concrete slab 13. FIG. 7(h) shows the erection of the third new precast concrete slab segment 23. FIG. 7(i) shows the construction of the vertical joint M. Figure 8 is a diagram illustrating a road bridge that has been replaced with a new concrete deck slab 2 after the tensioning process. Figures 5, 6, and 7 roughly correspond to the arrow views in Figures 4(1), 4(2), and 4(3), respectively. A bottom formwork is required when constructing vertical joint M, but an appropriate method can be selected, such as fixing the bottom formwork with an insert on the underside of the deck slab, using a suspended formwork from the top of the deck slab, or attaching a support to the top of the steel girder lower flange.

[0025] (1) As shown in Figure 1 or Figure 5(a), multiple replacement sections S are set in the replacement area P where the existing concrete deck slab 10 is to be replaced, divided in the width direction X. Multiple replacement sections S may also be set divided in the bridge axis direction Y. Below, three replacement sections S, the first replacement section S1, the second replacement section S2, and the third replacement section S3, will be explained as representatives. Here, the replacement section S corresponding to the lane on the median side is referred to as the first replacement section S1, the replacement section S corresponding to the lane on the shoulder side is referred to as the third replacement section S3, and the replacement section S corresponding to the middle between them is referred to as the second replacement section S2.

[0026] As shown in Figure 4(1), lane restrictions are implemented as appropriate. Specifically, lanes corresponding to the first replacement section S1 and the second replacement section S2 are closed (restricted for construction work). Then, for example, the remaining third replacement section S3 and the shoulder are used to reduce the three lanes to two lanes for use.

[0027] (2) As shown in FIGS. 5(a) to 5(c), the first existing concrete slab 11 in the first replacement section S1 among the multiple replacement sections S is removed (first existing slab removal process).

[0028] (2-1) As shown in Figure 5(b), the periphery of the first existing concrete slab 11 in the first replacement section S1 is cut. Then, the first existing concrete slab 11 is removed. If necessary, the first existing concrete slab 11 in the first replacement section S1 is further divided into multiple sections in the bridge axis direction Y, cut into sections, and removed section by section.

[0029] (3) As shown in FIG. 5(c), after the first existing deck removal process, a first new precast concrete deck segment 21 is laid in the first replacement section S1 (first new deck laying process).

[0030] (4) Here, as shown in Figure 4(2), lane restrictions are changed as appropriate. Specifically, the lane corresponding to the second replacement section S2 continues to be closed (restricted due to construction). Then, for example, the remaining first replacement section S1 and third replacement section S3 are used to open two lanes. Note that the first replacement section S1 may be put into service immediately after the installation of the first new precast concrete deck segment 21 is completed (between the time shown in Figure 5(c) and the time shown in Figure 6(d)).

[0031] (5) As shown in Figure 6(d), the existing concrete slab 10 in the second replacement section S2, which is the other part of the replacement area P, is removed (existing slab removal process). The second replacement section S2 may be a section adjacent to the first replacement section S1 in the width direction X, or may be a separate section that is not adjacent to the first replacement section S1 in the width direction X.

[0032] (6) As shown in FIG. 6(e), after the existing deck removal process, a second new precast concrete deck segment 22 is laid in the second replacement section S2 (new deck laying process).

[0033] (7) Here, as shown in FIG. 6(f), a cement-based filler such as concrete or mortar may be poured into the gap between the first new precast concrete slab segment 21 and the second new precast concrete slab segment 22 to construct a vertical joint M and connect the two. That is, in multiple replacement sections S divided in the width direction X, a vertical joint M of reinforced concrete structure is constructed between the new precast concrete slab segments 20 adjacent in the width direction X (joint construction process). This allows the first new precast concrete slab segment 21 and the second new precast concrete slab segment 22 to be structurally continuous, allowing them to be used in a state with sufficiently improved bearing capacity in the short term.

[0034] (8) Here, as shown in Figure 4 (3), lane restrictions are changed as appropriate. Specifically, the lane corresponding to the third replacement section S3 is closed (restricted for construction work). Then, for example, the remaining first replacement section S1 and second replacement section S2 are used to open two lanes.

[0035] (9) The existing slab removal process and the new slab laying process are repeated to replace the existing concrete slabs 10 in the multiple replacement sections S divided in the width direction X with multiple new precast concrete slab segments 20 (first new concrete slab segment 21, second new concrete slab segment 22, and third new concrete slab segment 23) lined up in the width direction X (slab replacement process). This is repeated a number of times according to the number of replacement sections S divided in the width direction X.

[0036] (9-1) In detail, after laying the second new precast concrete deck segment 22 in the second replacement section S2, the existing concrete deck 10 in the third replacement section S3, which is the other part of the first replacement section S1 and the second replacement section S2 in the replacement area P, is removed (existing deck removal process) as shown in Figure 7(g). Note that the third replacement section S3 may be a replacement section separated from the first replacement section S1 and adjacent to the second replacement section S2 in the width direction X, or may be a replacement section S between the first replacement section S1 and the second replacement section S2.

[0037] (9-2) After removing the existing concrete deck 10 in the third replacement section S3, a third new precast concrete deck segment 23 is laid in the third replacement section S3 as shown in Figure 7(h) (new deck laying process).

[0038] (10) As shown in FIG. 7(i), in a plurality of replacement sections S divided in the width direction X, vertical joints M of the reinforced concrete structure are constructed between adjacent new precast concrete slab segments 20 in the width direction X (joint construction process). The vertical joints M may be constructed either between the adjacent first new precast concrete slab segment 21 and second new precast concrete slab segment 22 or between the adjacent second new precast concrete slab segment 22 and third new precast concrete slab segment 23, or may be constructed in both. After the vertical joints M are constructed between the adjacent first new precast concrete slab segment 21 and second new precast concrete slab segment 22, but before they are constructed between the adjacent second new precast concrete slab segment 22 and third new precast concrete slab segment 23, the first replacement section S1 and the second replacement section S2 may be put into service first.

[0039] (11) Here, the newly constructed precast concrete slab segments 20 adjacent to each other in the width direction X are connected by the vertical joints M of the reinforced concrete structure, and therefore have sufficient short-term resistance to their own weight (dead load) and traffic load (live load). Therefore, the newly constructed precast concrete slab segments 20 adjacent to each other in the width direction X may be put into service as appropriate after the joint construction process and before the tensioning process. This allows the impact on traffic around the replacement area P to be reduced early on.

[0040] (12) After the joint construction process, as shown in Figure 8, prestress is introduced into the newly constructed precast concrete slab segments 20 lined up in the width direction X by means of PC steel members 60 inserted from one end to the other in the width direction X (tensioning process). In this way, prestress is finally introduced across the entire width at the end of the provisional service period, so that the newly constructed precast concrete slab segments 20 can be made into a PC structure (prestressed concrete structure). If the newly constructed precast concrete slab segment 20 that is replaced is an RC structure (precast RC slab segment), it can be made into a PC structure, and if the newly constructed precast concrete slab segment 20 is a PC structure (precast PC slab segment), not only can it be made into a PC structure with added prestress, but the vertical joints M can also be made into a PC structure, and sufficient prestress can be introduced into the shoulder portions at the side ends of the slab, and since it is possible to control the stress and cracks at the tensile edges in the vertical cross section perpendicular to the width direction X of the new concrete slab 2, the new concrete slab 2 can be provided with sufficient strength and long-term durability and can be used in service.

[0041] (13) Construction restrictions will be lifted as appropriate to allow the full width of road bridge 200 to be used.

[0042] In this way, according to the method for replacing the existing concrete deck 10 according to this embodiment, the existing road bridge 100 can be widened while a portion of the existing road bridge 100 or the newly constructed precast concrete deck segment 20 that has just been replaced is in service. This makes it possible to quickly reduce the impact on traffic in the vicinity of the replacement area P and to provide long-term durability to the road bridge 200 including the newly constructed concrete deck 2.

[0043] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0044] In addition, the components in the above-described embodiments may be replaced with known components as appropriate without departing from the spirit of the present invention. Furthermore, the above-described modifications may be combined as appropriate without departing from the spirit of the present invention.

[0045] The replacement method for an existing concrete deck 10 according to the embodiment includes a first existing deck removal process in which a plurality of replacement sections S are set up in a replacement area P of the existing concrete deck 10, divided in the width direction X, and a first existing concrete deck slab 11 is removed in a first replacement section S1 of the plurality of replacement sections S; a first new deck slab laying process in which a first new precast concrete deck slab segment 21 is laid in the first replacement section S1 after the first existing deck removal process; an existing deck slab removal process in which the existing concrete deck slab 10 is removed in a second replacement section S2, which is another part of the replacement area P; and a new deck slab laying process in which a new precast concrete deck slab segment 20 is laid in the replacement section S2 after the existing deck removal process. The replacement method for the existing concrete slab 10 includes a slab replacement process in which the existing concrete slab 10 in a plurality of replacement sections S divided in the width direction X is replaced with a plurality of new precast concrete slab segments 20 arranged in the width direction X by repeating the existing slab removal process and the new slab laying process; a joint construction process in which vertical joints M of an RC structure are constructed between adjacent new precast concrete slab segments 20 in the width direction X in the plurality of replacement sections S divided in the width direction X; and a tensioning process in which, after the joint construction process, prestress is introduced into the new precast concrete slab segments 20 arranged in the width direction X by PC steel members 60 inserted from one end to the other end in the width direction X. This allows the slab to be replaced while part of the widened road bridge is in service, and the road bridge 200 including the new concrete slab 2 can be made durable for a long time.

[0046] The road bridge 200 according to the embodiment includes an existing girder 30 and a concrete deck supported by the existing girder 30. The concrete deck has a plurality of new precast concrete deck segments 20 divided in the width direction X, and vertical joints M of an RC structure formed between adjacent new precast concrete deck segments 20 in the width direction X. The concrete deck is prestressed from one end to the other end in the width direction X. This allows the deck to be replaced while part of the widened road bridge remains in service, and ensures long-term durability for the road bridge 200 including the new concrete deck 2. [Explanation of symbols]

[0047] 100 Existing road bridge 10 Existing concrete deck 2. New concrete deck 20 New precast concrete slab segments 200 Road Bridge 30 Existing girder 40 Temporary support girder 50 crossbeam 60 PC steel material 70 Sheath 80 spaces 90 Fixture C Planned cutting position M vertical joint P Replacement Area S Replacement Section S1 First Replacement Section S2 Second Replacement Section S3 Third Replacement Section X Width direction Y bridge axis direction

Claims

1. The replacement area for the existing concrete deck is divided into multiple replacement sections in the width direction. a first existing concrete slab removal process for removing a first existing concrete slab in a first replacement section among the plurality of replacement sections; After the first existing deck removal process, a first new deck laying process is performed to lay a first new precast concrete deck segment in the first replacement section; an existing slab removal process of removing an existing concrete slab in a second replacement section which is another part of the replacement section; a new deck laying step of laying new precast concrete deck segments in the second replacement section after the existing deck removal step, A slab replacement process in which the existing concrete slabs in the plurality of replacement sections divided in the width direction are replaced with the plurality of new precast concrete slab segments arranged in the width direction by repeating the existing slab removal process and the new slab laying process; a joint construction process for constructing vertical joints of an RC structure between the newly constructed precast concrete slab segments adjacent to each other in the width direction in the plurality of replacement sections divided in the width direction; and a tensioning step of introducing prestress into the newly constructed precast concrete slab segments arranged in the width direction using PC steel members inserted from one side end to the other side end in the width direction after the joint construction step. A method for replacing existing concrete deck slabs.

2. After the joint construction process and before the tensioning process, the newly constructed precast concrete slab segments adjacent in the width direction are put into service. The method for replacing an existing concrete slab according to claim 1.

3. Existing girders and A concrete floor slab supported by the existing girder, The concrete slab has a plurality of new precast concrete slab segments divided in the width direction, and vertical joints of an RC structure formed between the new precast concrete slab segments adjacent in the width direction, The concrete slab is prestressed from one side end to the other side end in the width direction. Road bridge.

4. The new precast concrete slab segments are reinforced concrete structures. The road bridge according to claim 3.

5. The new precast concrete slab segments are PC structures. The road bridge according to claim 3.

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