Construction method of road bridge using PCa·PC bed plate

Abstract

To provide a construction of a road bridge using PCa / PC floor slabs applied to laying of a new road bridge such as an expressway and replacement of an existing road bridge.SOLUTION: PCa / PC floor slabs 1 are used including a notch 3 where a reinforcing bar 6 for joining PCa / PC floor slabs protrude in a bridge axis direction at an edge of the PCa / PC floor slab joint in the bridge axis direction and a raised portion 2 protruding in the bridge axis direction relative to the notch 3 at the edge perpendicular to the bridge axis direction. The PCa / PC floor slabs 1 are sequentially erected so that edge protrusion portions 2b of the raised portions 2, 2 of the PCa / PC floor slabs 1 adjacent to each other in the bridge axis direction abut each other in the bridge axis direction, and the reinforcing bars 6 for joining PCa / PC floor slabs of the notch 3 overlap each other. A PCa wall railing 10 is placed above the raised portion 2. A space filling concrete 8 is cast at a space filling portion 4 formed by the notch 3 abutting. A loop reinforcement is used as the reinforcing bar 6 for joining PCa / PC floor slabs, and a shear key 15 is placed at an abutting portion of the edge protrusion portions 2b of the raised portions 2, 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a construction method of a road bridge using a precast prestressed concrete floor slab (hereinafter, "PCa·PC floor slab"), which is implemented in the laying of a newly constructed road bridge such as a highway or the replacement of an existing road bridge, and enables rapid construction and high durability.

Background Art

[0002] In recent years, in road bridges such as highways, the aging of the floor slab part has progressed, and renewal works including the replacement of the floor slab part have increased. This type of renewal work generally involves removing an existing reinforced concrete floor slab (RC floor slab) that has aged, and then transporting a PCa·PC floor slab manufactured at a JIS factory to the site for rapid construction and high durability, and laying it in order in the bridge axis direction.

[0003] In addition, for the wall parapet, a precast concrete wall parapet (hereinafter, "PCa wall parapet") is also used for the purpose of rapid construction and high durability, and the PCa wall parapet is arranged at the end in the direction perpendicular to the bridge axis of the PCa·PC floor slab laid in the bridge axis direction.

[0004] For example, FIG. 6 illustrates a construction method of a road bridge using a PCa·PC floor slab and a PCa wall parapet.

[0005] In FIG. 6, the PCa·PC floor slab 1 is formed in a rectangular plate shape with a floor slab width of just over 2 m having a long side in the direction perpendicular to the bridge axis, and raised portions 2, 2 are formed at the ends (short side portions) on the side in the direction perpendicular to the bridge axis.

[0006] In addition, notch portions 3, 3 are formed at the joint portion (long side portion) in the bridge axis direction of the PCa·PC floor slab 1. Note that the shape of the PCa·PC floor slab 1 is not necessarily limited to a rectangular plate shape, and may be formed in a shape with an oblique angle (for example, a parallelogram, etc.) depending on the work area.

[0007] The embankment part 2 is continuously formed in the bridge axis direction of the PCa·PC floor slab 1, and the notch part 3 is continuously formed in the direction perpendicular to the bridge axis. In both cases, when the PCa·PC floor slab 1 is fabricated, concrete is placed simultaneously with the PCa·PC floor slab 1, and basically there is no boundary with the PCa·PC floor slab 1 and they are integrally formed.

[0008] Also, the upper end surface of the embankment part 2 is formed one step higher than the upper end surface of the PCa·PC floor slab 1. The notch parts 3 of the PCa·PC floor slabs 1 adjacent to each other in the bridge axis direction face each other and abut, thereby forming a packing part 4 for placing packing concrete at the joint part in the bridge axis direction between the PCa·PC floor slabs 1, 1. The packing part 4 opens in a concave groove shape directly above, is continuously formed in the direction perpendicular to the bridge axis of the PCa·PC floor slab 1, and its end is open.

[0009] Also, reinforcing bars 5 for joining the PCa·PC floor slab and the PCa wall railing are arranged at the upper end part of the embankment part 2, and reinforcing bars 6 for joining the PCa·PC floor slabs are arranged in the notch part 3. The reinforcing bars 5 for joining the PCa·PC floor slab and the PCa wall railing are erected at the upper end part of the embankment part 2 so as to form loops parallel to the vertical plane in the direction perpendicular to the bridge axis, and are arranged at equal intervals in the bridge axis direction.

[0010] The reinforcing bars 6 for joining the PCa·PC floor slabs are arranged in the bridge axis direction from the end face of the notch part 3 so as to form loops parallel to the vertical plane in the bridge axis direction, and are arranged at equal intervals in the direction perpendicular to the bridge axis.

[0011] Note that loop bars are arranged as the reinforcing bars 5 for joining the PCa·PC floor slab and the PCa wall railing and the reinforcing bars 6 for joining the PCa·PC floor slabs respectively. The loop bars 6, 6 are arranged so as to alternately overlap in the direction perpendicular to the bridge axis within the packing part 4 to form a loop bar joint.

[0012] A plurality of transverse reinforcing bars 7 are arranged in the direction perpendicular to the bridge axis within the loop bar joint, and packing concrete 8 is placed throughout the packing part 4. Thereby, the road bridge floor slab part of the PCa·PC structure composed of a plurality of PCa·PC floor slabs 1 is continuously formed in the bridge axis direction.

[0013] Symbol 9 is a drainage part, which is continuously formed in the axial direction of the bridge at the lower end of the raised part 2 in the direction perpendicular to the bridge axis of each PCa·PC floor slab.

[0014] The PCa wall railing 10 is arranged adjacent to each other in the axial direction of the bridge on the upper side of the raised parts 2 of a plurality of PCa·PC floor slabs and is continuously arranged in the axial direction of the bridge. In addition, the PCa·PC floor slab and the PCa wall railing joint reinforcing bar 11 is arranged at the lower end of the PCa wall railing 10, and the front skirt part 12 is formed at the lower end on the roadway side of the PCa wall railing 10.

[0015] The PCa·PC floor slab and the PCa wall railing joint reinforcing bar 11 is arranged to form a loop parallel to the vertical plane in the direction perpendicular to the bridge axis and is arranged at equal intervals in the axial direction of the bridge. In addition, the PCa·PC floor slab and the PCa wall railing joint reinforcing bar 11 is arranged to overlap alternately in the axial direction with the PCa·PC floor slab and the PCa wall railing joint reinforcing bar 5. Also, a loop bar joint is formed in the filling part 13 formed between the lower end of the PCa wall railing 10 and the raised part 2.

[0016] Then, the filling part 13 is filled with a high-performance and high-durability shrinkage-inhibiting mortar or the like as the filling mortar 14. Note that a loop bar is arranged as the PCa·PC floor slab and the PCa wall railing joint reinforcing bar 11.

[0017] In actual construction, following the erection of the PCa·PC floor slab, the filling concrete 8 including the raised part 2 is placed in the filling part 4 between each PCa·PC floor slab 1, 1. After the filling concrete 8 has hardened, the PCa wall railing 10 is arranged on the raised part 2. Then, the filling mortar 14 is filled in the filling part 13 between the PCa wall railing 10 and the raised part 2.

[0018] As another procedure, after the erection of the PCa·PC floor slab, with the filling concrete 8 not placed in the filling part 4 between each pair of PCa·PC floor slabs 1, the PCa wall railing 10 is first placed on the raised part 2, and then the filling concrete 8 is placed in the filling part 4 between each pair of PCa·PC floor slabs 1, and a high-performance and high-durability shrinkage-suppressing mortar or the like is filled as the filling mortar 14 in the filling part 13 under the PCa wall railing 10.

Prior Art Documents

Patent Documents

[0019]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0020] However, in the conventional construction method of a road bridge shown in FIG. 6, since the notch part 3 is continuously formed up to the end part in the direction perpendicular to the bridge axis of the PCa·PC floor slab 1 (right below the PCa wall railing 10), there is no raised part 2 at the end part in the direction perpendicular to the bridge axis of the filling part 4 formed by the notch parts 3, 3 at the joint part of the PCa·PC floor slabs 1, 1 in the bridge axis direction, and it is in an open state.

[0021] Therefore, at this part, it was necessary to separately arrange the reinforcing bars 5a for joining the PCa·PC floor slab and the PCa wall railing during on-site construction, place the filling concrete 8, and separately construct the raised part 2a continuous with the raised part 2.

[0022] Moreover, in order to separately construct the raised part 2a, it was necessary to install an end formwork (not shown in the figure) and a formwork for constructing the raised part (not shown in the figure) at the end part in the direction perpendicular to the bridge axis of the PCa·PC floor slab joint part. As a result, the on-site construction process increased, and a satisfactory construction period shortening could not be achieved.

[0023] In addition, when the PCa parapet 10 is placed in advance, it may take time to place the packing concrete 8 at the end of the packing part 4 (under the PCa parapet). Such a problem also existed in the construction method using a PCa·PC floor slab simply formed in a rectangular plate shape without the notch part 3.

[0024] The present invention is particularly an improvement and development of the conventional road bridge construction method shown in FIG. 6, and particularly aims to provide a road bridge construction method using a PCa·PC floor slab that enables rapid construction.

Means for Solving the Problems

[0025] The present invention has PCa·PC floor slab joint reinforcing bars protruding in the bridge axis direction at the PCa·PC floor slab joint end in the bridge axis direction as shown in FIGS. 1(a) and 1(b), and has a plurality of PCa·PC floor slabs having raised portions protruding in the bridge axis direction along the side portions of the PCa·PC floor slab joint reinforcing bars at the ends in the direction perpendicular to the bridge axis. It is a road bridge construction method for constructing a road bridge such as a highway, and is characterized by including the following steps.

[0026] (1) A step of arranging the PCa·PC floor slabs such that the raised portions of the PCa·PC floor slabs adjacent to each other in the bridge axis direction are continuous in the bridge axis direction and the PCa·PC floor slab joint reinforcing bars overlap each other. (2) A step of placing a PCa parapet on the raised portion. (3) A step of placing packing concrete at the joint in the bridge axis direction between the PCa·PC floor slabs adjacent to each other in the bridge axis direction.

[0027] In particular, since the raised portion is initially provided by factory production at the end of the filling portion formed at the joint in the bridge axis direction of the PCa·PC floor slab, there is no need for separate on-site construction during on-site construction. Therefore, the steps of installing the end formwork and the formwork for constructing the raised portion at this part during construction, arranging the PCa·PC floor slab and the reinforcing bars for joining the PCa wall railing on the PCa·PC floor slab side, and placing the filling concrete can be omitted. As a result, by reducing the on-site construction process, the construction period can be shortened and rapid construction can be achieved.

[0028] In addition, by using the PCa·PC floor slab having a notch (see FIGS. 4(a) and 4(b)), a concave groove-shaped filling portion that opens directly above is formed at the joint in the bridge axis direction of each PCa·PC floor slab by the opposing notches. Therefore, the filling concrete can be placed immediately without installing the bottom formwork of the filling portion.

[0029] Also, even when using a PCa·PC floor slab without a notch (see FIGS. 5(a) and 5(b)), the filling concrete can be placed by separately providing a bottom formwork for the filling portion.

[0030] In addition, it is preferable to arrange loop reinforcing bars as the reinforcing bars for joining the PCa·PC floor slabs. However, it is not particularly limited to loop reinforcing bars, and simply arranging the ends of the reinforcing bars to overlap each other to form a lap joint may also be acceptable.

[0031] Note that since the floor slab joining reinforcing bars are not arranged at the abutting portion in the bridge axis direction between the raised portions, the end of the PCa·PC floor slab in the direction perpendicular to the bridge axis has a structure that is mechanically separated in the bridge axis direction. However, since the PCa wall railing has a continuous structure in the bridge axis direction, it does not particularly become a weak point as a PCa·PC floor slab structure.

[0032] In this part, in some cases, for example, as shown in FIG. 2, by arranging a shear key 15 made of reinforcing bars or the like, the displacement between the PCa·PC floor slabs can be prevented. Also, this part is usually filled with mortar after the water washing treatment.

[0033] In addition, loop bars are arranged as PCa·PC floor slab and PCa wall railing joint bars on the floor slab side at the upper end of the raised portion. As the PCa wall railing, it is preferable to install a PCa wall railing provided with loop bars at the lower end as the PCa·PC floor slab and PCa wall railing joint bars on the PCa wall railing side. However, it is not particularly limited to this form. For example, the ends of the reinforcing bars may be protruded at both the upper end of the raised portion and the lower end of the PCa wall railing, and overlapped with each other to form a lap joint.

[0034] Note that it is preferable to fill the packing portion (see Fig. 1(a)) between the lower end of the PCa wall railing and the raised portion with high-performance and high-durability shrinkage-inhibiting mortar or the like as the packing mortar (see Fig. 1(a)).

Effects of the Invention

[0035] According to the construction method of the present invention, at the joint of the PCa·PC floor slab in the bridge axis direction, at the end (under the PCa wall railing) on the side perpendicular to the bridge axis, since the raised portion (end protruding portion 2b (see Fig. 1(a)) is provided from the beginning by factory production, there is no need to separately construct the raised portion during on-site construction. Therefore, the installation of the end formwork and the formwork for constructing the raised portion at this part, the arrangement of the PCa·PC floor slab and PCa wall railing joint bars on the floor slab side, and the placement of the packing concrete can all be omitted.

[0036] In addition, since the PCa wall railing can be installed prior to the placement of the packing concrete, the construction becomes simple, and the construction period can be shortened and rapid construction can be achieved by reducing the on-site construction process.

[0037] In addition, the placement of the packing concrete at the joint of the PCa·PC floor slab in the bridge axis direction does not interfere with the construction of the PCa wall railing, so they can be constructed independently.

[0038] In addition, in the case of the conventional construction method using a PCa·PC floor slab (see Fig. 6), since the bottom of the notch, so-called jaw (see Fig. 6), is a free end structurally, the ends may come into contact and chip off during lifting at a factory or the like or during erection at the site. However, according to the construction method of the present invention, since the PCa·PC floor slab has a raised portion at the end in the direction perpendicular to the bridge axis and there is no notch (see Figs. 4(a) and (b)), these problems can be solved.

Brief Description of Drawings

[0039]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0040] Figures 1-5 illustrate an embodiment of the present invention. For parts common to the conventional construction method illustrated in Figure 6, the same reference numerals are given and the description thereof is omitted or simplified.

[0041] In Figures 4(a) and (b), the raised portions 2 are each formed continuously in the bridge axis direction at the ends (short side ends) of the PCa·PC floor slab 1 in the direction perpendicular to the bridge axis, and a notch portion 3 is formed continuously in the direction perpendicular to the bridge axis between the raised portions 2 at both ends thereof.

[0042] Further, the raised portions 2 are formed in a substantially rectangular cross-sectional shape, and the upper end surface thereof is formed one step higher than the upper end surface of the PCa·PC floor slab 1.

[0043] The notch portion 3 is formed in a substantially L-shaped cross-section when viewed in the direction perpendicular to the bridge axis at the end (long side end) of the PCa·PC floor slab 1 in the bridge axis direction.

[0044] As a result, the ends of the raised portions 2 at both ends in the direction perpendicular to the bridge axis each protrude slightly in the bridge axis direction from the joint end in the bridge axis direction of the PCa·PC floor slab 1 (hereinafter referred to as "end protruding portion 2b") (see Figures 4(a) and (b)).

[0045] Further, at the end of the joint portion in the bridge axis direction between the PCa·PC floor slabs 1,1, a packing portion 4 in the form of a concave groove that opens upward is formed continuously in the direction perpendicular to the bridge axis by the notch portions 3 abutting against each other (see Figures 4(a) and (b)).

[0046] Also, between the ends in the direction perpendicular to the bridge axis of the PCa·PC floor slabs 1,1 (the lower side of the PCa wall railing 10), the end protruding portions 2b of the raised portions 2 on both sides abut against each other in the bridge axis direction and are joined together continuously in the bridge axis direction, and thereby the end in the direction perpendicular to the bridge axis of the packing portion 4 is completely closed.

[0047] Then, for example, as shown in FIG. 2, a plurality of shear keys 15 are arranged in the bridge axis direction between the end projecting portions 2b, 2b of the raised portions 2, 2. As a result, the ends of the PCa·PC floor slabs 1, 1 in the direction perpendicular to the bridge axis are, mechanically, in a structure separated in the bridge axis direction, but since the PCa wall railing 10 has a continuous structure in the bridge axis direction, it does not particularly become a weak point as a PCa·PC floor slab structure.

[0048] In addition, since the raised portion 2 is formed at the end portion (lower side portion of the PCa wall railing 10) of the PCa·PC floor slab 1 in the direction perpendicular to the bridge axis and there is no notch portion 3 in this portion, it is possible to prevent the end portion of the notch portion 3 from coming into contact and chipping during lifting of the PCa·PC floor slab 1 at a factory or the like or during erection at the site.

[0049] FIGS. 5(a) and 5(b) illustrate a type of PCa·PC floor slab 1 without a notch portion 3 between the end projecting portions 2b, 2b of the raised portions 2, 2 at both ends in the direction perpendicular to the bridge axis. In particular, the end projecting portions 2b, 2b of the raised portion 2 in the bridge axis direction project slightly in the bridge axis direction from the joint end portion of the PCa·PC floor slab 1 in the bridge axis direction.

[0050] When the PCa·PC floor slab 1 is used, there is no bottom formwork in the filling portion 4 formed between the adjacent PCa·PC floor slabs 1, 1 in the bridge axis direction, but the bottom formwork can be easily installed even on site.

[0051] The PCa·PC floor slab joint reinforcing bars 6 are arranged in the bridge axis direction from the opposing surfaces of the notch portions 3, 3 and are arranged to alternately overlap in the direction perpendicular to the bridge axis within the filling portion 4. In particular, loop reinforcing bars are arranged as the PCa·PC floor slab joint reinforcing bars 6, and the loop reinforcing bars 6, 6 are arranged to alternately overlap in the direction perpendicular to the bridge axis to form a loop reinforcing bar joint.

[0052] Further, for example, as shown in Fig. 1(b), a plurality of transverse reinforcement bars 7 are arranged in the loop bar joint in a direction perpendicular to the bridge axis, and filling concrete 8 is placed over the entire length in the filling portion 4. Thereby, a slab portion of a PCa·PC structure road bridge continuous in the bridge axis direction is formed.

[0053] In the case of a construction method using a PCa·PC slab of the type without a notch (see Figs. 5(a) and 5(b)), a bottom formwork may be installed in the filling portion 4 and the filling concrete 8 may be placed.

[0054] Also, the configuration and installation method of the PCa wall railing 10 and other configurations and construction methods are substantially the same as those of the construction method of a conventional PCa·PC structure road bridge shown in Fig. 6.

[0055] In actual construction, (1) First, a plurality of PCa·PC slabs 1 are sequentially arranged such that the ends in the bridge axis direction of the raised portions 2, 2 abut against each other in the bridge axis direction, the notch portions 3, 3 face each other and butt together, and the PCa·PC slab joint reinforcing bars 6 overlap each other alternately in a direction perpendicular to the bridge axis. (2) Next, a plurality of PCa wall railings 10 are arranged in the bridge axis direction on the raised portion 2 such that the PCa·PC slab on the railing side, the PCa wall railing joint reinforcing bar 11, the PCa·PC slab on the slab side, and the PCa wall railing joint reinforcing bar 5 overlap each other alternately in the bridge axis direction. (3) Next, a plurality of transverse bars 7 are arranged in the loop bar joint of the PCa·PC slab joint reinforcing bar 6. Then, filling concrete 8 is placed in the filling portion 4 between the PCa·PC slabs 1, 1, and filling mortar 14 is placed in the filling portion 13 under the PCa wall railing 10.

[0056] In such a construction method, since it is not necessary to construct the raised portion 2a (see Fig. 6) at the end in the direction perpendicular to the bridge axis of the joint portion between the PCa·PC floor slabs 1 in the bridge axis direction, the PCa·PC floor slab on the floor slab side, the reinforcing bar 5a for joining the PCa wall railing (see Fig. 6), and the end formwork to be arranged at the joint portion, and the formwork for constructing the raised portion 2a may not be provided. Further, since the PCa wall railing can be arranged prior to the placement of the filling concrete 8, the construction becomes simple and the construction period can be shortened by rapid construction.

Industrial Applicability

[0057] The present invention can realize rapid construction such as the laying of a newly constructed road bridge such as a highway or the replacement of an existing road bridge.

Explanation of Signs

[0058] 1 PCa·PC floor slab 2 Raised portion 2a Raised portion 2b End protruding portion of the raised portion 3 Notch portion 4 Filling portion 5 Reinforcing bar for joining the PCa·PC floor slab on the floor slab side and the PCa wall railing 6 Reinforcing bar for joining PCa·PC floor slabs 7 Horizontal reinforcing bar 8 Filling concrete 9 Drainage portion 10 PCa wall railing 11 Reinforcing bar for joining the PCa·PC floor slab on the wall railing side and the PCa wall railing 12 Front skirt portion of the PCa wall railing 13 Filling portion between the PCa·PC floor slab and the PCa wall railing 14 Filling mortar between the PCa·PC floor slab and the PCa wall railing 15 Shear key

Claims

In a method for constructing a road bridge by joining a plurality of PCa-PC slabs having PCa-PC slab joint reinforcing bars protruding in the bridge axis direction at the joint ends in the bridge axis direction, on the PCa-PC slabs, raised portions having a substantially rectangular cross-section for installing PCa wall parapets are integrally formed at both ends in the direction perpendicular to the bridge axis, with the upper end surfaces being one step higher than the upper end surfaces of the PCa-PC slabs. And both ends of the raised portions in the bridge axis direction protrude in the bridge axis direction from the joint ends in the bridge axis direction of the PCa-PC slabs, respectively. When the protruding portions at both ends in the bridge axis direction of the raised portions of adjacent PCa-PC slabs in the bridge axis direction are butted against each other, a packing portion for accommodating the PCa-PC slab joint reinforcing bars of the adjacent PCa-PC slabs is formed. A method for constructing a road bridge, characterized by including the following steps. (1) A step of sequentially butting the protruding portions of the raised portions of adjacent PCa-PC slabs in the bridge axis direction so that the raised portions are continuous in the bridge axis direction and the PCa-PC slab joint reinforcing bars overlap each other. (2) A step of arranging the PCa wall parapet on the raised portion. (3) A step of placing filling concrete in the packing portion formed at the joint end in the bridge axis direction of adjacent PCa-PC slabs in the bridge axis direction.

2. In the method for constructing a road bridge using the PCa-PC slab according to Claim 1, the packing portion for placing the filling concrete is formed by a notch portion that leaves a part of the lower surface side of the joint end in the bridge axis direction of the PCa-PC slab. A method for constructing a road bridge using a PCa-PC slab, characterized by this.

3. In the method for constructing a road bridge using the PCa-PC slab according to Claim 1 or 2, loop bars are arranged as the PCa-PC slab joint reinforcing bars. A method for constructing a road bridge using a PCa-PC slab, characterized by this.

4. In the method for constructing a road bridge using the PCa-PC slab according to any one of Claims 1 to 3, loop bars are arranged as the PCa-PC slab and PCa wall parapet joint reinforcing bars at the upper end portion of the raised portion and the lower end portion of the PCa wall parapet, respectively. A method for constructing a road bridge using a PCa-PC slab, characterized by this.

5. In the construction method of a road bridge according to any one of claims 1 to 4, a construction method of a road bridge using a PCa / PC floor slab, characterized in that packing mortar is filled in the filling portion between the raised portion of the PCa / PC floor slab and the PCa wall railing.

6. In the construction method of a road bridge according to any one of claims 1 to 5, a construction method of a road bridge using a PCa / PC floor slab, characterized in that shear keys are arranged between the end portions in the bridge axis direction of the raised portion.

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