Method for constructing wall parapet

Abstract

To provide a method for constructing a wall parapet that can easily align the height of the top of the wall parapet.SOLUTION: The method for constructing a wall parapet 6 according to one embodiment constructs the wall parapet 6 on a bridge girder of a bridge. The construction method comprises the steps for performing cantilever construction of a bridge girder of a bridge, constructing internal reinforced concrete 6A that forms an inner part of the wall parapet 6 on the bridge girder when performing the cantilever construction, and forming a surface part 6k of the wall parapet 6 on an inner surface 6h and a top surface 6j of the internal reinforced concrete 6A after completing the cantilever construction.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a parapet construction method for constructing a parapet on a bridge girder of a bridge. [Background technology]

[0002] Patent Document 1 describes a bridge parapet construction method. The bridge parapet construction method includes a step of constructing reinforcing bars, a step of constructing reinforced concrete for the rising section, a step of installing formwork, and a step of filling with filler. In the step of constructing reinforcing bars, the reinforcing bars for the parapet are constructed using scaffolding suspended from a vehicle installed on the bridge girder.

[0003] In the step of constructing the raised reinforced concrete section, concrete is poured onto the inside surface of the balustrade and the top surface of the balustrade excluding the covering portion on the top surface of the balustrade using scaffolding installed on the vehicle to construct the raised reinforced concrete section. In the step of installing the formwork, buried formwork and formwork are installed on the inside surface and top surface of the raised reinforced concrete section, respectively. In the step of filling the filler, filler is filled into the spaces defined by the raised reinforced concrete section and the buried formwork and formwork, respectively. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-186516 Summary of the Invention [Problem to be solved by the invention]

[0005] In the bridge parapet construction method described above, buried formwork and formwork are installed on the inner surface of the raised reinforced concrete and on the top surface of the raised reinforced concrete, respectively. However, when constructing the surface layer of the parapet, it is necessary to fine-tune the position of the formwork to ensure the finished shape. When constructing the bridge girder overhang on a bridge, the height of the deck slab located below the parapet may vary from the design value. In this case, it is necessary to align the top height of the parapet by adjusting the height or position of the formwork. Therefore, it is necessary to easily align the top height of the parapet.

[0006] The present disclosure aims to provide a method for constructing a wall balustrade that can easily align the height of the top end of the wall balustrade. [Means for solving the problem]

[0007] (1) The construction method for a wall parapet according to the present disclosure is a construction method for a wall parapet that builds a wall parapet on a bridge girder of a bridge. The construction method includes a step of performing cantilever construction of the bridge girder on the bridge, a step of constructing an internal reinforced concrete structure that forms the inside of the wall parapet on the bridge girder while the cantilever construction is being performed, and a step of forming a surface layer of the wall parapet on the inner surface and top surface of the internal reinforced concrete after the cantilever construction is completed.

[0008] In this parapet construction method, while the bridge girders are being extended, the internal reinforced concrete that forms the interior of the parapet is constructed on top of the bridge girders. Then, after the extension is completed, the surface layer of the parapet is formed on the inner and top surfaces of the internal reinforced concrete of the parapet. Therefore, the internal reinforced concrete of the parapet is constructed first during the extension, and the surface layer of the parapet is formed after the extension is completed and the superstructure is connected. Therefore, even if the deck slab height fluctuates during the extension, the surface layer is formed after the extension is completed and the deck slabs are connected, making it easy to align the top height of the parapet. Furthermore, the amount of work required for installing buried formwork, etc., can be reduced, contributing to improved workability.

[0009] (2) In the above (1), the step of forming the surface layer may include a step of spraying a finishing material onto the inner surface and the top surface. In this case, the surface layer is formed by spraying the finishing material onto the inner surface and the top surface. Therefore, the surface layer can be easily formed by spraying the finishing material.

[0010] (3) In the above (2), the step of forming the surface layer may further include a step of finishing the surface layer after the step of spraying the finishing material. The step of finishing the surface layer may include a step of placing a guide member in a position facing the surface onto which the finishing material has been sprayed, a step of fixing a jig for finishing the surface layer to the guide member, and a step of moving the jig along the guide member. In this case, by performing the step of finishing the surface layer after spraying the finishing material, the quality of the wall balustrade can be improved. Furthermore, by finishing the surface layer while the jig moves along the guide member, the surface layer can be finished efficiently.

[0011] (4) In the above (1), the step of forming the surface layer may include the steps of placing a movable formwork facing the inner surface and filling the gap between the inner surface and the movable formwork with a finishing material, and applying the finishing material to the top surface. In this case, by placing the movable formwork facing the inner surface and filling the gap between the inner surface and the movable formwork with the finishing material, the surface finishing of the finishing material can be omitted. Therefore, the application of the finishing material to the internal reinforced concrete can be easily performed.

[0012] (5) In the above (1), the step of forming the surface layer may include a step of applying a finishing material to the inner surface and a step of applying the finishing material to the top surface by a plastering method. In this case, applying the finishing material to the top surface by a plastering method eliminates the need for a formwork located on the opposite side of the inner surface of the top surface. This increases safety when applying the finishing material to the top surface.

[0013] (6) In any of the above (1) to (5), the step of constructing the internal reinforced concrete may include the steps of constructing reinforcing bars on the bridge girder, arranging anti-flow materials on the reinforcing bars to prevent concrete from flowing out, and pouring concrete onto the reinforcing bars. In this case, the anti-flow materials can prevent concrete from leaking when constructing the internal reinforced concrete.

[0014] (7) In the above (6), the anti-flow material may be composed of a lath mesh. In this case, the lath mesh can prevent concrete leakage and can be embedded in the concrete because the holes in the lath mesh allow the concrete to be integrated. In other words, since the lath mesh used as an anti-flow material does not need to be removed after the concrete is poured, the construction of the internal reinforced concrete can be facilitated. [Effects of the Invention]

[0015] According to the present disclosure, the height of the top of the wall balustrade can be easily aligned. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram schematically showing one step of a bridge construction work according to the embodiment. [Figure 2] 2(a), 2(b) and 2(c) are diagrams showing steps of a wall parapet construction method according to the embodiment. [Figure 3] 3(a), 3(b), and 3(c) are diagrams showing examples of outflow prevention materials according to the embodiment. [Figure 4] 4(a) and 4(b) are diagrams showing examples of outflow prevention materials according to the embodiment. [Figure 5] 5(a) and 5(b) are diagrams showing examples of outflow prevention materials according to the embodiment. [Figure 6] FIG. 6 is a diagram schematically showing one step of the bridge construction work according to the embodiment. [Figure 7]7(a) and 7(b) are diagrams showing an example of steps in a wall parapet construction method according to the embodiment. [Figure 8] 8(a), 8(b), and 8(c) are diagrams showing an example of steps in a wall parapet construction method according to the embodiment. [Figure 9] FIG. 9 is a diagram showing an example of steps of a wall parapet construction method according to the embodiment. [Figure 10] FIG. 10 is a diagram showing an example of steps of a wall parapet construction method according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the wall balustrade construction method according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are given the same reference numerals, and duplicate explanations will be omitted as appropriate. The drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional proportions etc. are not limited to those shown in the drawings.

[0018] Fig. 1 is a diagram showing an example of a bridge 1 and a cantilever erection device 10 to which the wall parapet construction method according to this embodiment is applied. As shown in Fig. 1, the cantilever erection device 10 is used, for example, at a construction site A where a road bridge is being constructed, when constructing the bridge 1 that constitutes a road bridge. At the construction site A, for example, in addition to the cantilever erection device 10, construction machinery such as a crane C is also arranged. Construction of the bridge 1 is carried out while materials necessary for building the bridge 1 are hoisted by the crane C or the like.

[0019] The exemplary cantilever erection device 10 is used for cantilever construction of a bridge girder 2 on a bridge 1. The bridge girder 2 is constructed by sequentially cantilevering main girder blocks B1 from the column capitals 4 at the upper ends of the piers 3 along the bridge axis direction D1. The cantilever erection device 10 is equipped with a pair of wagons 11, which are mobile work vehicles that can move on the bridge girder 2.

[0020] The wagons 11 are constructed to extend the bridge girder 2 from both ends of the existing blocks (main girder blocks B1 that have already been constructed) of the bridge girder 2 in the bridge axis direction D1 for each main girder block B1. Each wagon 11 extends outward from both ends of the existing blocks of the bridge girder 2 in the bridge axis direction D1.

[0021] Each vehicle 11 has a vehicle body 12 that has a truss structural surface and is arranged in the shape of a parallelogram, a load 13 suspended from the vehicle body 12, and rails 14 that allow the vehicle body 12 to move along the bridge axis direction D1 on the top surface of the existing block of the bridge girder 2. The load 13 is suspended from the vehicle body 12 and forms support during the cantilever construction of each main girder block B1 of the bridge girder 2. The load 13 includes scaffolding and formwork.

[0022] The construction method for the wall parapet according to this embodiment is carried out, for example, using the cantilever erection device 10 described above. Below, a method for constructing the wall parapet 6 (see FIG. 7(b)) will be described. For example, the wall parapet 6 is provided on each end of the deck slab 5 in the bridge axis transverse direction D2, which is a main girder block B1 extending in the bridge axis transverse direction D2 perpendicular to the bridge axis direction D1.

[0023] In the construction method for the wall parapet according to this embodiment, the wall parapet 6 is constructed using the scaffolding of a Volkswagen 11 (cargo 13) in addition to the cantilever construction of each main girder block B1 of the bridge girder 2. In this construction method, the wall parapet 6 is constructed on top of the bridge girder 2 of the bridge 1. Each step of the construction method for the wall parapet 6 will be described below.

[0024] First, the bridge girder 2 of the bridge 1 is cantilevered (cantilever construction process). In conjunction with the cantilever construction of the bridge girder 2, the vehicle 11 is installed, and construction of the main girder block B1 of the bridge girder 2 begins (process of constructing the main girder block). Construction of the main girder block B1 is carried out sequentially along the bridge axis direction D1. More specifically, the load 13 of the vehicle 11 is placed adjacent to the existing main girder block B1, scaffolding is constructed on top of the load 13, formwork is assembled on the scaffolding, and the main girder block B1 is constructed.

[0025] 2(a), construction of the wall parapet 6 begins on the scaffolding constructed together with the construction of the main girder block B1. In constructing the wall parapet 6, for example, chipping is performed on the top surface 5c and end surface 5d of the end 5b of the deck slab 5 (main girder block B1) in the direction perpendicular to the bridge axis D2.

[0026] Then, while the cantilever construction is being carried out, internal reinforced concrete 6A that forms the inside of the wall parapet 6 is constructed on top of the bridge girder 2 (process of constructing internal reinforced concrete). More specifically, reinforcing bars 6b are constructed on top of the bridge girder 2. The construction of the reinforcing bars 6b is carried out, for example, on the upper surface 5c of the end 5b of the deck 5 at the scaffolding of the Volkswagen 11. At this time, multiple reinforcing bars 6b that form the framework of the wall parapet 6 are placed on top of the end 5b of the deck 5.

[0027] Next, the formwork 7 is placed on the footing of the Volkswagen 11 so as to extend vertically upward from the end face 5d of the deck 5, and the outflow prevention material 20 is placed on the opposite side of the formwork 7 as viewed from the reinforcing bars 6b (step of placing the outflow prevention material). The outflow prevention material 20 is placed to prevent the filled concrete from spilling out. The outflow prevention material 20 may be a shape-retaining material that maintains the shape of the filled concrete. The outflow prevention material 20 may also be a simple formwork.

[0028] Various examples of the outflow prevention material 20 will be described below. As shown in Figures 2, 3(a), 3(b), and 3(c), the outflow prevention material 20 may be a mesh-like outflow prevention material 21. The mesh-like outflow prevention material 21 includes a lath net 21b located on the opposite side of the formwork 7 from the reinforcing bars 6b, and linear members 21c that fasten the reinforcing bars 6b to the lath net 21b.

[0029] The lath netting 21b is, for example, a blind-shaped lath netting. The wire members 21c are, for example, wires. The mesh-shaped outflow prevention material 21 is fixed to the reinforcing bars 6b by fastening the reinforcing bars 6b to the lath netting 21b with the wire members 21c. The mesh-shaped outflow prevention material 21 may further include lath reinforcing bars 21d, and the wire members 21c may fasten the reinforcing bars 6b to the lath netting 21b and the lath reinforcing bars 21d.

[0030] Alternatively, the mesh-shaped outflow prevention material 21 may be formed by fixing the lath mesh 21b to the reinforcing bars 6b using tubular members 21f, separators 21g, and retainers 21h instead of the linear members 21c. The retainers 21h may be, for example, FormTie (registered trademark). The tubular members 21f may be, for example, single pipes. For example, multiple tubular members 21f contact the surface of the lath mesh 21b facing away from the reinforcing bars 6b, and separators 21g penetrate the lath mesh 21b between the multiple tubular members 21f. Then, retainers 21h, which are fixed to the separators 21g and located on the opposite side of the tubular members 21f from the lath mesh 21b, press the multiple tubular members 21f against the lath mesh 21b. This causes the lath mesh 21b to contact the multiple reinforcing bars 6b, thereby fixing the mesh-shaped outflow prevention material 21 to the multiple reinforcing bars 6b.

[0031] When the outflow prevention material 20 is a mesh-type outflow prevention material 21, for example, the mesh-type outflow prevention material 21 is embedded while being fixed to a plurality of reinforcing bars 6b. In other words, with the mesh-type outflow prevention material 21, the concrete filled between the formwork 7 and the mesh-type outflow prevention material 21 is integrated with the finishing material 9, which will be described later, through the holes in the lath mesh 21b, so there is no need to remove the mesh-type outflow prevention material 21 after the concrete has hardened.

[0032] As shown in Figures 4(a) and 4(b), the outflow prevention material 20 may be a textured backing frame 22. The textured backing frame 22 has, for example, a textured sheet 22b and a backing frame 22c to which the textured sheet 22b is attached. The textured sheet 22b is fixed to the backing frame 22c by, for example, an adhesive. When the outflow prevention material 20 has the backing frame 22c in this way, concrete leakage can be more reliably prevented.

[0033] The textured sheet 22b has a textured surface on the side opposite to the surface bonded to the support frame 22c, and the textured support frame 22 is arranged so that the textured surface faces the multiple reinforcing bars 6b. For example, the textured support frame 22 is fixed to the multiple reinforcing bars 6b by tubular members 22f, separators 22g, and retainers 22h, similar to the lath mesh 21b described above. In this state, concrete is poured between the textured support frame 22 and the formwork 7.

[0034] After the concrete has hardened, the uneven surface mounting frame 22 is removed to form the internal reinforced concrete 6A with the unevenness 6x formed on its surface. The formation of the unevenness 6x on the surface of the internal reinforced concrete 6A improves the unity between the internal reinforced concrete 6A and the finishing material 9 (see FIG. 7), which will be described later, when the finishing material 9 is applied to the surface of the internal reinforced concrete 6A.

[0035] As shown in Figures 5(a) and 5(b), the outflow prevention material 20 may be a retarder-applied backing frame 23. The retarder-applied backing frame 23 has a backing frame 23c to which a retarder 23b is applied. The retarder 23b is a set retarder that delays the hardening of concrete. The retarder-applied backing frame 23 is arranged so that the retarder 23b faces the multiple reinforcing bars 6b. The retarder 23b may be a liquid or a film. If the retarder 23b is a liquid, the retarder 23b is applied to the backing frame 23c. If the retarder 23b is a film, the retarder 23b is attached to the backing frame 23c.

[0036] For example, the retarder-equipped support frame 23 is fixed to the plurality of reinforcing bars 6b by tubular members 23f, separators 23g, and retainers 23h, in the same way as the lath mesh 21b described above. In this state, concrete is poured between the retarder-equipped support frame 23 and the formwork 7. After the concrete has hardened to the point where it can stand on its own, the retarder-equipped support frame 23 is removed, thereby constructing internal reinforced concrete 6A whose surface is not completely hardened.

[0037] The surface of this internal reinforced concrete 6A is roughened to form irregularities 6x on the surface. At this time, the surface of the internal reinforced concrete 6A is washed out using a water jet method to form the irregularities 6x on the surface. For example, a high-pressure washer 23k sprays water onto the surface of the unhardened internal reinforced concrete 6A to form the irregularities 6x. In this case, when the finishing material 9 is applied to the surface of the internal reinforced concrete 6A, the integrity of the internal reinforced concrete 6A and the finishing material 9 can be improved.

[0038] As described above, as shown in FIG. 2(c), the inner reinforced concrete 6A is constructed by pouring concrete between the outflow prevention material 20 and the formwork 7. As mentioned above, the outflow prevention material 20 may be removed from the inner reinforced concrete 6A after the inner reinforced concrete 6A has hardened, or may be buried in the inner reinforced concrete 6A. For example, the inner reinforced concrete 6A is cured until the cantilever construction is completed.

[0039] As mentioned above, the construction of the internal reinforced concrete 6A is carried out during the cantilever construction. Figure 6 is a diagram that shows a schematic of the bridge 1 after the cantilever construction is completed. As shown in Figure 6, after the cantilever construction is completed, the bridge girder 2 (main girder block B1) that protrudes from one of the multiple piers 3 is connected to the bridge girder 2 that protrudes from the other, completing the connection of the multiple main girder blocks B1 lined up along the bridge axis direction D1.

[0040] As shown in Figures 7(a) and 7(b), after the cantilever construction is completed, a surface layer 6k of the wall parapet 6 is formed on the inner surface 6h and top surface 6j of the internal reinforced concrete 6A (a surface layer forming step). For example, the surface layer 6k is formed by spraying a finishing material 9 onto the inner surface 6h and top surface 6j (a spraying step). When the finishing material 9 is sprayed onto the top surface 6j, the spraying is performed with a backing frame W installed on the surface (outer surface) opposite the inner surface 6h of the internal reinforced concrete 6A.

[0041] For example, the finishing material 9 is made of a cement-based material that hardens over time. The finishing material 9 is, for example, mortar (high-strength mortar as an example). The material of the finishing material 9 is not particularly limited as long as it is a material that allows the finishing material 9 to become self-sustaining over time. The material of the finishing material 9 may be the same as or different from the material of the concrete of the internal reinforced concrete 6A.

[0042] The finishing material 9 is sprayed onto the inner surface 6h and the top surface 6j to a predetermined thickness. At least one of the thickness of the finishing material 9, the height of the finishing material 9 relative to the inner surface 6h, and the height of the finishing material 9 relative to the top surface 6j may be measured by a scanner. For example, the scanner may measure the thickness of the finishing material 9 by irradiating light onto the applied finishing material 9 and receiving the light reflected from the surface of the finishing material 9. In this case, the thickness of the finishing material 9 can be controlled with high precision.

[0043] After the finishing material 9 is sprayed, the surface layer 6k is finished (the surface layer finishing process). Finishing the surface layer 6k involves, for example, finishing the surface of the balustrade 6 by plastering and adjusting the height of the balustrade 6. To adjust the height of the balustrade 6, a marker indicating the target height of the finishing material 9 may be placed on the top surface 6j of the internal reinforced concrete 6A. As an example, the marker may be a rod-shaped member (e.g., a bolt) that protrudes from the top surface 6j by the target height. In this case, the height of the balustrade 6 can be set to the target height by applying the finishing material 9 to the top surface 6j to the extent that the rod-shaped member is buried. As described above, the formation of the surface layer 6k is completed after the application of the finishing material 9 to the top surface 6j is completed.

[0044] Figures 8(a), 8(b), and 8(c) are diagrams showing a process for forming the surface layer 6k by a method other than spraying. As shown in Figures 8(a), 8(b), and 8(c), the surface layer 6k is formed by placing a movable formwork 25 in a position facing the inner surface 6h and filling the space between the inner surface 6h and the movable formwork 25 with the finishing material 9 (the process for filling the finishing material).

[0045] The finishing material 9 is, for example, mortar to which a quick-hardening agent (or agent) has been added. In this case, the finishing material 9 can be quickly hardened, allowing for rapid construction. The finishing material 9 may also be mortar with high thixotropy. In this case, the finishing material 9 has the property of flowing when an external force is applied and remaining self-supporting when the external force is removed.

[0046] The surface of the movable formwork 25 facing the inner surface 6h is flat. Therefore, a flat surface layer 6k is formed by the hardening of the filled finishing material 9, making it unnecessary to finish the surface layer 6k. For example, after the hardening of the finishing material 9, the movable formwork 25 is moved upward, and the finishing material 9 is filled between the moved upward movable formwork 25 and the inner surface 6h.

[0047] In this way, the finishing material 9 is applied to the inner surface 6h by repeatedly filling the space between the movable formwork 25 and the inner surface 6h with the finishing material 9, allowing the finishing material 9 to harden, and then moving the movable formwork 25 upward. Then, with a backing frame W installed on the surface of the inner reinforced concrete 6A opposite the inner surface 6h, the finishing material 9 is applied to the top surface 6j (a process of applying the finishing material to the top surface). After the finishing material 9 hardens and the backing frame W is removed, the formation of the surface layer 6k is completed.

[0048] FIG. 9 is a diagram showing a modified example of applying a finishing material 9 to the top surface 6j. As shown in FIG. 9, after applying the finishing material 9 to the inner surface 6h, the finishing material 9 may be applied to the top surface 6j by a plastering method (a process of applying a finishing material by a plastering method). In this case, the finishing material 9 applied to the top surface 6j is leveled with a trowel 26 to form a surface layer 6k on the top surface 6j. This eliminates the need to install a backing frame W on the surface of the interior reinforced concrete 6A opposite the inner surface 6h, thereby contributing to improved safety.

[0049] Fig. 10 is a diagram showing a modified example of finishing the surface layer 6k. As shown in Fig. 10, the finishing of the surface layer 6k may be performed by a finishing device 30 including a guide member 31 disposed at a position facing the surface onto which the finishing material 9 has been sprayed, and a jig 32 fixed to the guide member 31.

[0050] The guide member 31 includes a pair of first guides 31b extending in a first direction A1 and a second guide 31c extending in a second direction A2 intersecting the first direction A1 between the pair of first guides 31b. The second direction A2 is, for example, a direction perpendicular to the first direction A1. The pair of first guides 31b are aligned along the second direction A2.

[0051] The second guide 31c is movable along the first direction A1. A jig 32 is detachably attached to the second guide 31c. The jig 32 is attached to the second guide 31c so as to be movable along the second direction A2. The jig 32 moves in the first direction A1 as the second guide 31c moves along the first guide 31b, and also moves in the second direction A2 along the second guide 31c.

[0052] For example, multiple types of jigs 32 can be attached and detached to the second guide 31c. The jigs 32 may include a first jig and a second jig that is different from the first jig. For example, the first jig is a jig that removes excess material from the finishing material 9, and the second jig is a jig that smooths the surface of the finishing material 9. After attaching the first jig to the second guide 31c to remove the excess material, the second jig is attached to the second guide 31c to smooth the surface of the finishing material 9, thereby enabling efficient finishing by the finishing device 30.

[0053] An example of a process for finishing the surface layer 6k using the finishing device 30 will be described. First, a guide member 31 is placed in a position facing the surface onto which the finishing material 9 has been sprayed (a process for placing a guide member). Specifically, a pair of first guides 31b are placed in positions facing the finishing material 9, and then a second guide 31c is placed so as to straddle the pair of first guides 31b. Alternatively, a pair of first guides 31b and second guides 31c fixed to each other in advance so as to form an H-shape may be placed on the finishing material 9.

[0054] Next, the jig 32 is fixed to the guide member 31 (a jig fixing step). Then, the jig 32 is moved along the guide member 31 to finish the surface layer portion 6k (a jig moving step). For example, a first jig is fixed to the second guide 31c and the first jig is moved while removing excess material, and then the first jig is removed from the second guide 31c and the second jig is fixed to the second guide 31c. Then, the second jig is moved along the second guide 31c while smoothing the surface of the finishing material 9. Through the above steps, the finishing of the surface layer portion 6k is completed.

[0055] Next, the effects of the parapet construction method according to this embodiment will be explained. As shown in Figures 2 and 7, in the parapet construction method according to this embodiment, when the cantilever construction of the bridge girder 2 on the bridge 1 is being carried out, the internal reinforced concrete 6A that forms the inside of the parapet 6 is constructed on the deck 5 that forms the bridge girder 2. Then, after the cantilever construction is completed, the surface layer 6k of the parapet 6 is formed on the inner surface 6h and top surface 6j of the internal reinforced concrete 6A of the parapet 6.

[0056] Therefore, the internal reinforced concrete 6A of the wall parapet 6 is constructed in advance during cantilever construction, and the surface layer 6k of the wall parapet 6 is formed after cantilever construction is completed and the main girder block B1, which is the superstructure, is connected. Therefore, even if the height of the deck slab 5 fluctuates during cantilever construction, the surface layer 6k is formed after cantilever construction is completed and the deck slab 5 is connected, so the height of the top of the wall parapet 6 can be easily made uniform. Furthermore, the amount of work required for installing buried formwork, etc. can be reduced, contributing to improved workability.

[0057] As described above, the step of forming the surface layer 6k may include the step of spraying the finishing material 9 onto the inner surface 6h and the top surface 6j. In this case, the surface layer 6k is formed by spraying the finishing material 9 onto the inner surface 6h and the top surface 6j. Therefore, the surface layer 6k can be easily formed by spraying the finishing material 9.

[0058] As described above, the step of forming the surface layer portion 6k may further include a step of finishing the surface layer portion 6k after the step of spraying the finishing material 9. As shown in Fig. 10, the step of finishing the surface layer portion 6k may include a step of placing a guide member 31 at a position facing the surface onto which the finishing material 9 has been sprayed, a step of fixing a jig 32 for finishing the surface layer portion 6k to the guide member 31, and a step of moving the jig 32 along the guide member 31. In this case, by performing the step of finishing the surface layer portion 6k after spraying the finishing material 9, the quality of the wall balustrade 6 can be improved. Furthermore, by finishing the surface layer portion 6k while the jig 32 moves along the guide member 31, the finishing of the surface layer portion 6k can be performed efficiently.

[0059] 8, the step of forming the surface layer 6k may include the steps of placing a movable formwork 25 in a position facing the inner surface 6h and filling the space between the inner surface 6h and the movable formwork 25 with a finishing material 9, and applying the finishing material 9 to the top surface 6j. In this case, by placing the movable formwork 25 in a position facing the inner surface 6h and filling the space between the inner surface 6h and the movable formwork 25 with the finishing material 9, it is possible to omit the step of finishing the surface of the finishing material 9. This makes it easy to apply the finishing material 9 to the interior reinforced concrete 6A.

[0060] As shown in Figure 9, the process of forming the surface layer 6k may include a process of applying a finishing material 9 to the inner surface 6h and a process of applying the finishing material 9 to the top surface 6j by a plastering method. In this case, applying the finishing material 9 to the top surface 6j with a trowel 26 eliminates the need for a formwork (backing frame W) located on the opposite side of the top surface 6j from the inner surface 6h. This improves safety when applying the finishing material 9 to the top surface 6j.

[0061] 2 and 3, the process of constructing the internal reinforced concrete 6A may include the steps of constructing reinforcing bars 6b on the bridge girder 2, placing anti-flow materials 20 on the reinforcing bars 6b to prevent the concrete from leaking, and pouring concrete into the reinforcing bars 6b. In this case, the anti-flow materials 20 can prevent the concrete from leaking when constructing the internal reinforced concrete 6A.

[0062] As mentioned above, the outflow prevention material 20 may be composed of lath mesh 21b. In this case, the lath mesh 21b can prevent concrete leakage and can be embedded because the concrete and finishing material 9 can be integrated through the holes in the lath mesh 21b. In other words, it is not necessary to remove the lath mesh 21b used as the outflow prevention material 20 after the concrete is poured. This makes it easy to construct the internal reinforced concrete 6A.

[0063] The above describes embodiments and various examples of the wall balustrade construction method according to the present disclosure. However, the wall balustrade construction method according to the present disclosure is not limited to the above-described embodiments or examples, and may be further modified within the scope of the gist described in the claims. In other words, the content and order of the steps in the wall balustrade construction method, as well as the shape, size, type, number, and arrangement of the devices and materials used in the construction method, can be appropriately changed within the scope of the above gist.

[0064] For example, the type of the above-mentioned finishing material 9 can be further modified. The finishing material 9 may be a high-performance material whose composition is adjusted to meet the desired properties. In this case, the strength and durability of the finishing material 9 can be increased, thereby improving the quality of the surface layer 6k of the wall balustrade 6. Examples of the above-mentioned high-performance material include a finishing material 9 containing amorphous spherical particles of SiO2 (for example, silica fume (registered trademark)), a finishing material 9 containing resin cement, or a finishing material 9 containing a setting retarder.

[0065] The finishing material 9 may be made of commercially available materials. The finishing material 9 may be a material that is mixed in a plant. Furthermore, the finishing material 9 may be made by adding admixtures on-site. In this case, it is possible to reduce the cost of the finishing material 9 and save labor. Furthermore, the finishing material 9 may be made of mortar to which hollow microspheres have been added.

[0066] The hollow microspheres are made of an alkali-resistant resin. They can be mixed with an admixture. The hollow microspheres may be contained in a water-soluble sheet or may be fed into an agitator truck together with the water-soluble sheet. When the finishing material 9 is made of mortar containing hollow microspheres, the durability and freeze-thaw resistance of the wall balustrade 6 can be improved. [Explanation of symbols]

[0067] 1...bridge, 2...bridge girder, 3...pier, 4...column head, 5...deck slab, 5b...end, 5c...top surface, 5d...end surface, 6...wall parapet, 6A...internal reinforced concrete, 6b...reinforcement bar, 6h...inner surface, 6j...top surface, 6k...surface portion, 6x...unevenness, 7...formwork, 9...finishing material, 10...extension erection device, 11...wagen, 13...load, 14...rail, 20...flow prevention material, 21...mesh-shaped flow prevention material, 21b...lath net, 21c...linear member, 21d...lath reinforcement steel bar, 21f...tubular member, 21g...separator, 21h...holding portion, 22...uneven surface support frame, 22b ...sheet with textured surface, 22c...backing frame, 22f...tubular member, 22g...separator, 22h...holding portion, 23...backing frame with retarder, 23b...retarder, 23c...backing frame, 23f...tubular member, 23g...separator, 23h...holding portion, 23k...high-pressure washer, 25...mobile formwork, 26...trowel, 30...finishing device, 31...guide member, 31b...first guide, 31c...second guide, 32...jig, A...site, A1...first direction, A2...second direction, B1...main girder block, C...crane, D1...bridge axis direction, D2...direction perpendicular to the bridge axis, W...backing frame.

Claims

1. A wall parapet construction method for constructing a wall parapet on a bridge girder of a bridge, A step of performing cantilever construction of bridge girders on the bridge; a step of constructing an internal reinforced concrete structure that constitutes an interior of the wall parapet on the bridge girder while the cantilever construction is being performed; After the cantilever construction is completed, a step of forming a surface layer of the wall balustrade on the inner surface and top surface of the internal reinforced concrete; Equipped with How to install a wall parapet.

2. The step of forming the surface layer includes a step of spraying a finishing material onto the inner surface and the top surface, A method for constructing a wall parapet according to claim 1.

3. The step of forming the surface layer portion further includes a step of finishing the surface layer portion after the step of spraying the finishing material, The step of finishing the surface layer portion includes a step of arranging a guide member at a position facing the surface onto which the finishing material is sprayed, a step of fixing a jig for finishing the surface layer portion to the guide member, and a step of moving the jig along the guide member. A method for constructing a wall parapet according to claim 2.

4. The step of forming the surface layer portion includes: a step of placing a movable formwork at a position facing the inner surface and filling a finishing material between the inner surface and the movable formwork; and applying the finishing material to the top surface. A method for constructing a wall parapet according to claim 1.

5. The step of forming the surface layer portion includes: applying a finish to the interior surface; and applying the finishing material to the top surface by a plastering method. A method for constructing a wall parapet according to claim 1.

6. The step of constructing the internal reinforced concrete includes: constructing a reinforcing bar on the bridge girder; A step of placing an outflow prevention material on the reinforcing bar to prevent concrete from outflowing; Pouring the concrete onto the reinforcing bars; Equipped with A method for constructing a wall parapet according to claim 1 or claim 2.

7. The outflow prevention material is composed of a lath net. A method for constructing a wall parapet according to claim 6.

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