Horseshoe-shaped dowel composite deck removal method

Abstract

To provide a horseshoe-shaped dowel composite slab removing method with which slabs can be peeled off and removed from a main girder safely and efficiently in a short time with high workability.SOLUTION: A horseshoe dowel J1 composite slab removing method for removing a horseshoe dowel composite slab in which a concrete slab C1 and main girders G1-G4 are combined using the horseshoe dowel J1 includes: a slab bridge-axis perpendicular direction cutting process in which the concrete slab C1 is cut at predetermined intervals L1 with a concrete cutter into a size that can be transported along a direction Y perpendicular to the bridge axis; a slab bridge-axis direction cutting process in which the concrete slab C1 is cut to a predetermined depth (D1) approximately vertically downward from an upper surface of the concrete slab C1 along a bridge axis direction X on the main girders G1-G4 with a concrete cutter so as to pass near a center of the horseshoe dowel J1; and a slab peeling process in which cut pieces of the concrete slab C1, which are cut to a size that can be transported in the slab bridge-axis perpendicular direction cutting process and the slab bridge-axis direction cutting process, are peeled off from the main girders G1-G4 with a slab peeling machine.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a composite deck removal method for removing composite decks, and more particularly to a horseshoe dowel composite deck removal method for peeling off and removing a composite deck during composite deck replacement work on a composite steel girder bridge in which the deck and main girder are joined together with a horseshoe dowel. [Background technology]

[0002] Conventionally, horseshoe-shaped dowels are used as fittings to connect the main girders and deck slabs to each other in composite steel girder bridges (see Figures 2, 5, 8, etc.). Compared to dowel bars, which are used to prevent slippage in non-composite plate girder bridges, these horseshoe-shaped dowels provide a stronger bond, making them difficult to remove using conventional deck slab removal methods. For this reason, deck replacement work for composite steel girder bridges with horseshoe-shaped dowels typically involves cutting and removing the existing deck slab on the main girders in the axial direction while suspended by an erection crane. The remaining deck concrete on the main girder flanges is then removed using a breaker or similar tool, and a new deck slab is then erected (see Figures 4 to 6). However, this removal method is inefficient due to the amount of work required and the large amount of concrete debris generated. Therefore, the development of a new deck removal method is desirable to improve workability and shorten the process.

[0003] Patent Document 1 discloses a method for removing a concrete slab, which includes a hole drilling step of drilling a hole in a haunch portion, a crack generating step of generating a crack in the haunch portion that starts from the hole drilled in the hole drilling step and reaches the dowel, a dowel cutting step of cutting the dowel inside the haunch portion from the crack generated in the crack generating step, and a slab separating step of separating the concrete slab from the girder, using the crack generated in the crack generating step as a boundary (see claim 1 in the scope of claims of Patent Document 1, paragraphs

[0015] to

[0029] of the specification, and Figures 1 to 3 of the drawings, etc.).

[0004] Patent Document 2 also discloses a method for removing a composite girder deck slab, which includes a first cutting step of cutting the deck slab in the section from which the deck slab is to be removed in a direction perpendicular to the bridge axis at multiple locations in the bridge axis direction; a second cutting step of cutting the concrete between the main girder and the deck slab together with the shear stop members by a predetermined length in the bridge axis direction with a wire saw; and a removal step of lifting and removing the deck slab cut in the second cutting step, wherein the first cutting step involves using a wet concrete cutter to cut the concrete of the existing deck slab from the top surface to a predetermined depth, and then cutting the remaining concrete down to the bottom surface with a dry concrete cutter, and the second cutting step and the removal step are repeatedly performed from one end of the bridge axis direction of the section from which the deck slab is to be removed to the other (see claim 1 in the scope of claims of Patent Document 2, paragraphs

[0016] to

[0023] of the specification, and Figures 1 to 15 of the drawings, etc.).

[0005] However, in both the concrete deck removal method described in Patent Document 1 and the composite girder deck removal method described in Patent Document 2, the shear-stopping dowels are removed by cutting them horizontally slightly above the steel girders, which makes it impossible to work on them without setting up temporary scaffolding, etc., which creates the problem that the deck cannot be removed efficiently.

[0006] Furthermore, Patent Document 3 describes a method for removing a composite deck slab with a horseshoe-shaped dowel, in which the horseshoe-shaped dowel is cut and removed with a cutter (see Claim 1 in the claims of Patent Document 3, paragraphs

[0027] to

[0033] in the specification, and Figures 2, 5, and 7 in the drawings, etc.).

[0007] However, the composite deck removal method described in Patent Document 3 involves cutting one inclined horseshoe dowel in two places horizontally to remove it, which takes time to cut the horseshoe dowel, and does not solve the aforementioned problem of the deck not being able to be removed efficiently in a short time. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6826872 [Patent Document 2] Patent No. 7020978 [Patent Document 3] Japanese Patent Publication No. 2023-1686 Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, the present invention was devised in consideration of the above-mentioned problems, and its purpose is to provide a method for removing horseshoe-shaped dowel composite deck slabs that is highly workable, efficient, safe, and can be peeled off and removed from the main girders in a short period of time. [Means for solving the problem]

[0010] The horseshoe dowel composite deck removal method according to the first invention is a horseshoe dowel composite deck removal method for removing a horseshoe dowel composite deck in which a concrete deck and a main girder are joined together with a horseshoe dowel, and includes a deck slab bridge axis direction cutting step in which the concrete deck slab is cut at predetermined intervals into transportable sizes along the direction perpendicular to the bridge axis with a concrete cutter; a deck slab bridge axis direction cutting step in which the concrete deck slab is cut to a predetermined depth approximately vertically from the top surface of the concrete deck slab downward along the bridge axis direction on the main girder with a concrete cutter so as to pass near the center of the horseshoe dowel, thereby cutting the arc portions of the horseshoe dowel; and a deck slab peeling machine for removing the cut pieces of the concrete deck slab cut to a transportable size in the deck slab bridge axis direction cutting step and the deck slab bridge axis cutting step. The arc portion of the horseshoe-shaped dowel cut in the deck bridge axial cutting step is linearly extended, and each cut piece is The method is characterized by including a deck slab peeling process for peeling the deck slab from the main girder.

[0011] The horseshoe-shaped dowel composite deck removal method according to the second invention is the first invention, wherein in the deck bridge axial direction cutting step, the concrete deck is cut so that there is one cutting line along the bridge axial direction for each main girder, passing near the center of the horseshoe-shaped dowel. It is characterized by:

[0012] According to the first and second inventions, the horseshoe-shaped dowel composite deck slab can be peeled off and removed from the main girder with high workability, efficiency, safety, and in a short time. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing an outline of a horseshoe dowel-type composite deck slab removal method according to an embodiment of the present invention. [Figure 2] Figure 2 is a vertical cross-sectional view along the bridge axis direction showing an overview of the deck slab bridge axis cutting process in the horseshoe-shaped dowel composite deck removal method. [Figure 3] Figure 3 is a flowchart showing the steps of the horseshoe-shaped dowel composite deck removal method. [Figure 4] FIG. 4 is a perspective view showing an outline of a conventional composite deck removal method for Case 1, in which the composite parts on the main girders G1 to G4 are left and then removed by chipping them off later with a chipping machine such as a breaker. [Figure 5] FIG. 5 is a vertical cross-sectional view along the bridge axis direction showing an overview of the deck slab bridge axis direction cutting process of the conventional composite deck removal method of Case 1 in the same case. [Figure 6] FIG. 6 is a flowchart showing the flow of each step in the conventional composite deck removal method of Case 1 in the same case. [Figure 7] FIG. 7 is a perspective view showing an outline of a conventional non-composite deck removal method in Case 2, in which the concrete deck C1 is removed by peeling off the main girders using a deck peeling machine. [Figure 8] FIG. 8 is a vertical cross-sectional view along the bridge axis direction showing an overview of the deck slab bridge axis direction cutting process of the conventional non-composite deck removal method of Case-2 in the same case. [Figure 9] FIG. 9 is a flowchart showing the flow of each process of the conventional non-composite deck removal method of Case 2 in the same case. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, one embodiment of the horseshoe dowel composite deck slab removal method according to the present invention will be described in detail with reference to the drawings.

[0015] [Horseshoe-shaped dowel composite deck removal method] Using Figures 1 to 3, a horseshoe dowel composite deck slab removal method according to an embodiment of the present invention will be described, comparing it with a conventional composite deck slab removal method shown in Figures 4 to 6 and a non-composite deck slab removal method shown in Figures 7 to 9. Figure 1 is a perspective view showing an overview of the horseshoe dowel composite deck slab removal method according to an embodiment of the present invention, and Figure 2 is a vertical cross-sectional view along the bridge axis showing an overview of the deck slab bridge axis direction cutting process of the horseshoe dowel composite deck slab removal method according to this embodiment. Also, Figure 3 is a flowchart showing the flow of each process of the horseshoe dowel composite deck slab removal method according to this embodiment.

[0016] Also, Figure 4 is a perspective view showing an outline of the conventional composite deck removal method for Case 1, in which the composite parts on the main girders G1 to G4 are left and then removed by chipping off using a chipping machine such as a breaker, and Figure 5 is a vertical cross-sectional view along the bridge axis showing an outline of the deck slab bridge axis direction cutting process of the conventional composite deck removal method for Case 1. Also, Figure 6 is a flowchart showing the flow of each process of the conventional composite deck removal method for Case 1.

[0017] Fig. 7 is a perspective view showing an outline of the conventional non-composite deck removal method for Case 2, in which the non-composite concrete deck C1 is removed by peeling it off from the main girder with a deck peeling machine, and Fig. 8 is a vertical cross-sectional view along the bridge axis showing an outline of the deck axial cutting process in the conventional non-composite deck removal method for Case 2. Fig. 9 is a flowchart showing the flow of each process in the conventional non-composite deck removal method for Case 2.

[0018] In this embodiment, as shown in Figures 1, 4, and 7, a concrete deck C1 is placed on a main girder consisting of four steel girders G1 to G4, and each of the main girders G1 to G4 is joined to the concrete deck C1 with a horseshoe-shaped dowel J1. This example illustrates a case in which the concrete deck C1 is removed from a composite steel girder bridge B1 and a new precast deck is installed to replace the existing one. Note that wall parapets and other details are omitted. This composite steel girder bridge B1 is assumed to have a bridge width W1 of 10 m, which is the center-to-center distance from the main girders G1 to G4. In the figures, the symbol X indicates the bridge axis direction X, the symbol Y indicates the direction perpendicular to the bridge axis Y, and the symbol Z indicates the up-down direction Z.

[0019] (Cutting process perpendicular to the deck slab axis) As shown in Figures 1 and 3, in the horseshoe-shaped dowel composite deck removal method according to this embodiment, first, a deck slab cutting process perpendicular to the bridge axis is carried out, in which the concrete deck C1 is cut at predetermined intervals along the direction Y perpendicular to the bridge axis using a concrete cutter.

[0020] In the process of cutting the concrete deck C1 perpendicular to the bridge axis, the concrete deck C1 is cut with a concrete cutter at predetermined intervals along the direction perpendicular to the bridge axis into transportable sizes. Specifically, in the process of cutting the concrete deck C1 perpendicular to the bridge axis, the deck is cut at predetermined intervals L1 (approximately 2 m) along the direction Y perpendicular to the bridge axis.

[0021] As shown in Figures 4 and 7, this process is present in both the conventional deck removal methods, Case-1 and Case-2, and, similar to the horseshoe-shaped dowel composite deck removal method according to this embodiment, the concrete deck C1 is cut with a concrete cutter at predetermined intervals L1 (approximately 2 m) that allow it to be transported along the direction Y perpendicular to the bridge axis.

[0022] (Deck slab bridge axial cutting process) 1 to 3, in the horseshoe dowel composite deck removal method according to this embodiment, a deck slab bridge axis direction cutting step is performed in which a concrete cutter is used to cut the concrete deck C1 along the bridge axis direction X on the main girders G1 to G4. In this deck slab bridge axis direction cutting step, the concrete deck C1 is cut approximately vertically downward from the top surface of the concrete deck C1 directly above the central axis of each of the main girders G1 to G4 to a predetermined depth D1 so as to pass near the center of the horseshoe dowel J1.

[0023] In this embodiment, as shown in Figures 1 and 2, the arc portion of the horseshoe dowel J1 is cut, and a single line is cut along the bridge axis direction X directly above each main girder G1-G4 to a depth D1 of 270 mm, which is equivalent to the thickness of the concrete slab C1 excluding the haunch portion where the portion joined to the main girders G1-G4 remains. Here, "only one line per main girder" refers to cutting along a single cutting line CL along the bridge axis direction X for each main girder, so that there are not two cutting lines CL on each main girder along the bridge axis direction X, as in the composite slab removal method described in Patent Document 3 mentioned in the background art (see Figure 1). The cutting depth D1 of 270 mm is merely an example, and it goes without saying that the cutting depth D1 will vary depending on the thickness of the concrete slab C1.

[0024] Furthermore, four main girders G1 to G4 are installed at approximately equal intervals across the bridge width W1 = 10m, so by completing the aforementioned process of cutting the deck slab perpendicular to the bridge axis and this process, rectangular cut pieces P1 of the concrete deck C1, approximately 2m x 3.3m, are formed, divided into three sections per cross section. However, in this process, the concrete deck C1 is cut to a depth of 270mm, leaving gaps along the cutting line CL, but the main girders G1 to G4 and the concrete deck C1 are still connected by the haunch, which is part of the composite section Ca.

[0025] On the other hand, as shown in Figures 4 and 5, in the conventional composite deck removal method for Case 1, the deck is lifted with a crane or other lifting machine so that there are two cutting lines CL along the bridge axis direction X, not directly above each of the main girders G1 to G4, but just beside each main girder a certain distance away from each main girder in the direction perpendicular to the bridge axis Y, so that the composite section Ca where the main girders G1 to G4 with the horseshoe-shaped dowel J1 and the concrete deck C1 are joined remains on each main girder, and then cut into cut pieces P1' divided into approximately three parts per cross section and removed.

[0026] Also, as shown in Figures 7 and 8, in the conventional non-composite deck removal method for Case 2, the concrete deck C1 is cut so that the section Ca where the main girders G1 to G4 with the horseshoe-shaped dowel J1 are joined to the concrete deck C1 remains on each main girder, but near the center of the main girders G2 and G3, which are the center of the span of the concrete deck C1, rather than directly above each of the main girders G1 to G4, with the cutting line CL being one line along the bridge axis direction X so as to divide the concrete deck C1 into two per cross section, and rectangular cut pieces P1" of approximately 2m x 5m are formed.

[0027] (Deck stripping process) Next, as shown in Figures 1 and 3, in the horseshoe-shaped dowel composite deck removal method according to this embodiment, a deck stripping process is carried out in which the concrete deck C1 is divided into three pieces per cross section, P1, in the deck cut perpendicular to the bridge axis direction and deck cut in the bridge axis direction, and the cut pieces P1 are peeled off from each of the main girders G1 to G4 using a deck stripping machine.

[0028] As described above, the cut pieces P1 of the concrete deck slab C1 are formed by cutting the concrete deck slab C1 at 2-m intervals in the deck slab bridge axis direction cutting process, and by forming slits along the central axis of each of the main girders G1 to G4 in the deck slab bridge axis direction cutting process, resulting in three rectangular pieces of approximately 2 m x 3.3 m per cross section (see Figure 1). Also, as shown in Figure 2, the arc portion of the horseshoe-shaped dowel J1 is cut in the deck slab bridge axis direction cutting process. Therefore, when the cut pieces P1 with the slits are hooked and lifted with a deck slab peeling machine in this process, the cut arc portion of the horseshoe-shaped dowel J1 is stretched and straightened, allowing the cut pieces P1 of the concrete deck slab C1 to be easily peeled off from each of the main girders G1 to G4 without being hooked by the horseshoe-shaped dowel J1.

[0029] Furthermore, the cut pieces P1 of the concrete slab C1 peeled off in this process are rectangular pieces measuring approximately 2m x 3.3m, as mentioned above, and can be easily transported and removed.

[0030] On the other hand, as shown in Figure 4, in the conventional composite deck removal method of Case 1, the aforementioned deck slab transverse to the bridge axis cutting process and deck slab bridge axial cutting process are used to cut and divide the rectangular concrete deck C1 into three pieces P1' of approximately 2m x 3m per cross section, and then transport them out. However, as shown in Figures 5 and 6, directly above each of the main girders G1 to G4, composite sections Ca where the main girders G1 to G4 are joined to the concrete deck C1 are left behind, and the conventional composite deck removal method of Case 1 requires a large-scale composite section chipping process in which this composite section is chipped off and removed with a chipping machine such as a breaker.

[0031] Furthermore, as shown in Figure 7, in the conventional non-composite deck removal method of Case 2, the deck slab is cut and divided into two rectangular cut pieces P1" of approximately 2m x 5m per cross section through the aforementioned deck slab transverse-axis cutting process and deck slab axial-axis cutting process. However, as shown in Figure 8, in the conventional non-composite deck removal method of Case 2, unlike the horseshoe-shaped dowel composite deck removal method of this embodiment, the arc portion of the horseshoe-shaped dowel J1 is not cut, and when the cut piece P1" with the slit is hooked and lifted with a deck stripping machine, most of the concrete in the composite section Ca remains attached to the horseshoe-shaped dowel J1. As a result, a large amount of concrete must be removed in the composite section chipping process described below, and it takes a long time to chip it all away. Furthermore, when the horseshoe-shaped dowels are densely arranged, the adhesion resistance between the horseshoe-shaped dowels and the cut piece P1" is high, making it often difficult to remove them with a deck stripping machine.

[0032] (Synthesis partial cutting process) Next, as shown in Figure 3, in the horseshoe-shaped dowel composite deck removal method according to this embodiment, when the cut pieces of the concrete deck C1 are removed in the deck removal process, a composite portion chipping process is carried out in which the composite portion concrete remaining on each of the main girders G1 to G4 is chipped off and removed using a chipping machine such as a breaker.

[0033] 2, after cutting near the axis of each main girder, which is the center of the arc portion of the horseshoe dowel J1, the cut piece P1 is peeled off with a deck peeling machine, so that the concrete of the composite portion Ca is hardly held in place by the horseshoe dowel J1, and only a small amount of concrete needs to be chipped off in this process. Therefore, with the horseshoe dowel composite deck removal method according to this embodiment, the composite portion chipping process can be completed in an extremely short time.

[0034] With the completion of this process, the deck removal work using the horseshoe dowel composite deck removal method of this embodiment is completed.

[0035] In contrast, in the conventional composite deck removal method of Case 1, although the deck peeling process is not performed, all of the composite section Ca where the main girders G1 to G4 and the concrete deck C1 are joined remains, as shown in Figures 4 and 5. For this reason, the amount of concrete that needs to be chipped away in the composite section chipping process is enormous, requiring a significant amount of chipping time, resulting in poor workability overall and making it impossible to efficiently, safely, and quickly cut and remove the concrete deck C1 from the main girders G1 to G4.

[0036] Furthermore, even in the conventional non-composite deck removal method of Case 2, as shown in Figure 8, the arc portion of the horseshoe-shaped dowel J1 is not cut during the deck peeling process, and most of the concrete in the composite portion Ca remains attached to the horseshoe-shaped dowel J1. As a result, more concrete needs to be chipped off in the composite portion chipping process than in the horseshoe-shaped dowel composite deck removal method of this embodiment. Similarly, this requires a significant amount of chipping time, resulting in poor overall workability and making it impossible to efficiently, safely, and quickly cut and remove the concrete deck C1 from the main girders G1-G4. Furthermore, as mentioned above, when the horseshoe-shaped dowels are densely arranged, the adhesion resistance between the horseshoe dowels and the cut pieces P1" is high, making it often difficult to peel them off using a deck peeling machine.

[0037] On the other hand, in the horseshoe dowel composite deck removal method according to this embodiment, the concrete of the composite part Ca is hardly held in place by the horseshoe dowel J1, and less concrete needs to be chipped off, so the composite part chipping process can be completed in a short time, resulting in high overall workability and enabling the concrete deck C1 to be cut and removed from the main girders G1 to G4 efficiently, safely and in a short time.

[0038] The above is a detailed description of the horseshoe dowel composite deck slab removal method according to an embodiment of the present invention. However, the above-described and illustrated embodiments are merely specific examples of the present invention. Therefore, the technical scope of the present invention should not be interpreted as being limited by these embodiments. [Explanation of symbols]

[0039] B1:Synthetic steel girder bridge G1~G4: Main girders C1: Concrete deck P1, P1', P1": Cutting pieces Ca: Synthetic part J1: Horseshoe dowel CL: Cutting line

Claims

1. A horseshoe dowel composite deck removal method for removing a horseshoe dowel composite deck in which a concrete deck and a main girder are combined with a horseshoe dowel, A deck slab bridge axis perpendicular cutting process in which the concrete deck is cut at predetermined intervals along the bridge axis perpendicular direction with a concrete cutter into transportable sizes; a deck axial direction cutting process in which the concrete deck is cut to a predetermined depth using a concrete cutter along the bridge axis direction on the main girder, approximately vertically downward from the top surface of the concrete deck, so as to pass through the vicinity of the center of the horseshoe-shaped dowel, thereby cutting the arc portion of the horseshoe-shaped dowel; The cut pieces of the concrete deck, which have been cut to a transportable size in the deck bridge axis direction cutting step and the deck bridge axis direction cutting step, are linearly stretched by a deck peeling machine along the arc of the horseshoe-shaped dowel cut in the deck bridge axis direction cutting step, and each cut piece is peeled off from the main girder. A horseshoe-shaped dowel composite deck removal method characterized by:

2. In the deck bridge axial cutting process, each main girder is cut so as to pass near the center of the horseshoe-shaped dowel. The concrete deck is cut so that there is one cutting line along the bridge axis. thing The method for removing a horseshoe-shaped dowel composite deck slab according to claim 1,

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