Joint structure of precast floor slabs

Abstract

To provide a joint structure of a precast floor slab capable of improving durability of pavement.SOLUTION: A joint structure of a precast floor slab includes a plurality of precast floor slabs 3 in which end surface side walls are disposed adjacent to each other with a gap S therebetween, a 38a portion 2 that supports an end portion side 3a of the plurality of precast floor slabs 3, and a joint portion 4 provided in the gap S, and the joint portion 4 includes a reinforcing bar 41 that protrudes from the end surface side 38a of the plurality of precast floor slabs 3 and a concrete portion 48 in which the reinforcing bar 41 is embedded.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a joint structure for a precast deck slab. [Background technology]

[0002] Precast decks have traditionally been installed in roads such as tunnels. When the width of a road exceeds 10 m, a configuration has been disclosed in which precast decks are arranged adjacent to each other in the width direction and the ends are supported by intermediate walls (middle walls) (see Patent Document 1 below). Joints are sometimes provided between the ends of the precast decks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6834055 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a problem in that if expansion and contraction occurs in the joints due to deflection of the precast deck, it may induce deterioration such as cracks in the pavement installed on top of the precast deck.

[0005] Therefore, the present invention has been made in consideration of the above circumstances, and provides a joint structure for precast deck slabs that can improve the durability of pavement. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention employs the following means. In other words, the precast deck joint structure of the present invention comprises a plurality of precast decks arranged adjacent to each other with gaps between their end faces, a wall portion supporting the ends of the plurality of precast decks, and a joint portion provided in the gap, and the joint portion has reinforcing bars protruding from the end faces of the plurality of precast decks and a concrete portion in which the reinforcing bars are embedded.

[0007] In this precast deck joint structure, multiple precast decks are installed on a wall, and then the rebars protruding from the end faces of the precast decks are embedded in concrete to form the joints. This eliminates the need for joints between precast decks as in the past, thereby suppressing deterioration of the pavement and improving its durability.

[0008] Furthermore, in the joint structure of the precast deck according to the present invention, the reinforcing bars at the joint portions may be formed in a loop shape.

[0009] In the joint structure of a precast deck slab configured in this manner, the reinforcing bars at the joint section are formed in a loop shape, a so-called loop joint structure, so there is no need to ensure a large width at the joint section, which improves on-site workability. [Effects of the Invention]

[0010] The joint structure of the precast deck slab according to the present invention can improve the durability of the pavement. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a joint structure of a precast deck according to one embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of a main part of a joint structure of a precast deck according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a joint structure for a precast deck according to one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a joint structure of a precast deck according to one embodiment of the present invention. As shown in FIG. 1, a joint structure 1 for precast decks according to this embodiment (hereinafter, may be simply referred to as a "joint structure") is installed in a tunnel 10, for example.

[0013] The axial direction in which the tunnel 10 extends is referred to as the axial direction Y. The substantially horizontal direction of the tunnel 10 that is substantially perpendicular to the axial direction Y is referred to as the width direction X. The direction that is substantially perpendicular to the axial direction Y and the width direction X is referred to as the direction Z.

[0014] The joint structure 1 includes an inner wall (wall portion) 2, a plurality of precast floor slabs 3, and joint portions 4. The joint portions 4 are provided in gaps S between the plurality of precast floor slabs 3.

[0015] The middle wall 2 is installed on a mounting surface 11 at the bottom inside the tunnel 10. The mounting surface 11 is a surface facing upward. The middle wall 2 extends in the axial direction Y. The thickness direction of the middle wall 2 faces the width direction X. The middle wall 2 is formed of, for example, reinforced concrete. The middle wall 2 divides the area above the mounting surface 11 into spaces S1 and S2 in the width direction X.

[0016] FIG. 2 is an enlarged view of a main part of the joint structure 1. As shown in FIG. As shown in FIG. 2, the precast floor slab 3 has width direction reinforcing bars 31, axial direction reinforcing bars (not shown), PC steel members 33, and a floor concrete portion .

[0017] The widthwise reinforcing bars 31 are reinforcing bars that extend in the width direction X. A plurality of widthwise reinforcing bars 31 are arranged in the axial direction Y at intervals.

[0018] The width-direction reinforcing bars 31 have a pair of straight portions 31a and a loop portion 31b. The straight portion 31a extends in the width direction X. The straight portion 31a extends into the gap S. The pair of straight portions 31a are spaced apart in the vertical direction Z. The loop portion 31b connects the ends of the pair of straight portions 31a. The loop portion 31b is formed in a loop shape that curves so as to bulge toward the adjacent precast deck 3.

[0019] The axial reinforcing bars extend in the axial direction Y. A plurality of the axial reinforcing bars are arranged at intervals in the width direction X and the up-down direction Z. Note that if the precast deck slab 3 has sufficient strength, the axial reinforcing bars may be omitted.

[0020] The PC steel members 33 extend in the width direction X. The PC steel members 33 are pre-tensioned steel members. A plurality of the PC steel members 33 are arranged at intervals in the up-down direction Z and the axial direction Y.

[0021] The concrete floor portion 38 has width-direction reinforcing bars 31, axial reinforcing bars, and prestressing steel members 33 embedded therein. The thickness direction of the concrete floor portion 38 faces the vertical direction Z. The end faces 38a of the concrete floor portion 38 facing the adjacent concrete floor portion 38 are inclined with respect to the vertical direction Z so as to move away from the adjacent concrete floor portion 38 as they extend upward. The end faces 38a of the concrete floor portion 38 may also be along a vertical plane. The end faces 38a of adjacent concrete floor portions 38 are arranged with a gap S between them.

[0022] The end 3a of the precast floor slab 3 on the gap S side is supported by the middle wall 2 via an intervening member 22. The end 3a of the precast floor slab 3 may also be supported directly on the upper surface of the middle wall 2.

[0023] The joint portion 4 has a protruding reinforcing bar (reinforcing bar) 41, a joint reinforcing bar 42, and a joint concrete portion (concrete portion) 48. The joint portion 4 is disposed in a gap S. The length of the gap S in the width direction X is, for example, about 300 mm.

[0024] The protruding bars 41 are reinforcing bars in the widthwise reinforcing bars 31 of the precast floor slab 3 that protrude into the gap S from the end face 38a of the floor concrete portion 38. The protruding bars 41 have a portion that protrudes into the gap S from the end face 38a of the straight portion 31a and a loop portion 31b. Of adjacent precast floor slabs 3, the protruding bars 41 (referred to as protruding bars 41A) of one precast floor slab 3 (referred to as precast floor slab 3A) and the protruding bars 41 (referred to as protruding bars 41B) of the other precast floor slab 3 (referred to as precast floor slab 3) are arranged alternately in the axial direction Y. Note that multiple protruding bars 41A of the precast floor slab 3A may be arranged in the axial direction Y, and multiple protruding bars 41B of the precast floor slab 3B may be arranged in the axial direction Y next to them. The arrangement order of the protruding bars 41A of the precast floor slab 3A and the protruding bars 41B of the precast floor slab 3B in the axial direction Y can be set as appropriate.

[0025] The loop portion 31b of the protruding reinforcement 41A of the precast deck 3A is positioned closer to the precast deck 3B side than the loop portion 31b of the protruding reinforcement 41B of the precast deck 3B. The loop portion 31b of the protruding reinforcement 41B of the precast deck 3B is positioned closer to the precast deck 3A side than the loop portion 31b of the protruding reinforcement 41A of the precast deck 3A.

[0026] The protruding bars 41A of the precast deck 3A and the protruding bars 41B of the precast deck 3B are arranged at the same height. However, the protruding bars 41A of the precast deck 3A and the protruding bars 41B of the precast deck 3B may be arranged at different heights.

[0027] The connecting reinforcing bars 42 extend in the axial direction Y. When viewed from the axial direction Y, multiple connecting reinforcing bars 42 are arranged in the space surrounded by the protruding bars 41A and the protruding bars 41B. Within the space surrounded by the protruding bars 41A and the protruding bars 41B, the multiple connecting reinforcing bars 42 are arranged below the upper straight portion 31a, above the lower straight portion 31a, and inside the loop portions 31b on both sides in the width direction X. The arrangement position of the connecting reinforcing bars 42 can be set as appropriate. The connecting reinforcing bars 42 may also be arranged outside the space surrounded by the protruding bars 41A and the protruding bars 41B.

[0028] The PC steel members 33 do not protrude into the gap S from the end surface 38a of the floor concrete portion 38. Note that the PC steel members 33 may also protrude into the gap S from the end surface 38a of the floor concrete portion 38.

[0029] The joint concrete portion 48 is concrete filled between the end face 38a of the precast deck 3A and the end face 38a of the precast deck 3B. Protruding reinforcement 41 and joint reinforcing bars 42 are embedded in the joint concrete portion 48. The top surface of the joint concrete portion 48 is located on the same plane as the top surface of the precast deck 3.

[0030] An embedded formwork 23 is provided between the joint concrete portion 48 and the middle wall 2. The embedded formwork 23 is installed on the upper surface of the middle wall 2, and concrete is poured between the end face 38a of the precast floor slab 3A and the end face 38a of the precast floor slab 3B, thereby forming the joint concrete portion 48.

[0031] The paved road 51 is laid along the upper surface of the precast deck 3 and the upper surface of the joint portion 4.

[0032] In the joint structure 1 configured in this manner, multiple precast deck slabs 3 are installed in the middle wall 2. Joint rebars 42 are arranged, and the width-direction rebars 31 protruding from the end face 38a of the precast deck slab 3 and the joint rebars 42 are embedded in concrete to form a joint concrete section 48, thereby constructing the joint section 4. This eliminates the need for joints between the precast deck slabs 3 as in the past, thereby suppressing deterioration of the paved road 51 and improving its durability.

[0033] Furthermore, since the protruding reinforcement 41 of the joint portion 4 is formed in a loop shape, which is a so-called loop joint structure, there is no need to ensure a large length dimension in the width direction X of the joint portion 4, which improves workability on site.

[0034] Furthermore, by properly securing the joint portion 4, it will be possible to accommodate half-section construction when replacing the deck in the future.

[0035] Furthermore, by making the precast deck 3 continuous through the joints 4 in the narrow space of the tunnel 10, it is possible to improve the durability of the road deck.

[0036] The shapes and combinations of the components shown in the above-described embodiment are merely examples, and various modifications can be made based on design requirements, etc., within the scope of the present invention.

[0037] For example, in the embodiment described above, the precast deck 3 is made of prestressed concrete having PC steel members 33, but this is not limiting. The precast deck 3 may also be made of reinforced concrete without PC steel members 33.

[0038] Furthermore, in the embodiment described above, a loop joint structure in which the width direction reinforcing bars 31 are formed in a loop shape is employed at the joint portion 4, but this is not limited to this. At the joint portion 4, the width direction reinforcing bars 31 of the precast floor slab 3A and the width direction reinforcing bars 31 of the precast floor slab 3B may be joined using a mechanically anchored combined lap joint structure that combines mechanical anchoring and a lap joint. The joint structure between the width direction reinforcing bars 31 of the precast floor slab 3A and the width direction reinforcing bars 31 of the precast floor slab 3B can be set as appropriate.

[0039] In addition, in the embodiment shown above, the precast floor slab 3 is divided into two in the width direction X and two pieces are installed, but this is not limited to this. The precast floor slab 3 may be divided into three or more in the width direction X and three or more pieces may be installed. In this case, joints 4 are formed between each pair of the precast floor slabs 3.

[0040] The Sustainable Development Goals (SDGs) are 17 international goals adopted at the United Nations Summit in September 2015. The precast deck joint structure 1 according to this embodiment can contribute to achieving one of the 17 SDGs, for example, goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation." [Explanation of symbols]

[0041] 1 Precast deck joint structure 3, 3A, 3B Precast deck 3a end 4 Joint 41 Protruding bars (reinforced bars) 38a End face 48 Joint concrete section (concrete section) S Gap

Claims

1. Multiple precast deck slabs arranged adjacent to each other with gaps between their end faces; a wall portion supporting the ends of the plurality of precast floor slabs; a joint portion provided in the gap, The joint portion is Reinforcing bars protruding from the end faces of the plurality of precast floor slabs; A joint structure for a precast deck having a concrete section in which the reinforcing bars are embedded.

2. The joint structure for precast deck slabs according to claim 1 , wherein the reinforcing bars at the joint portions are formed in a loop shape.

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