Floor slab connection structure and connection method

Abstract

To provide a connection structure of floor slab superior in workability and concrete filling.SOLUTION: A connection structure of floor slab 1 includes: a pair of precast floor slabs; a rebar joint 4 that is placed in a gap 5 between the pair of floor slabs and extends linearly forming a perforated lap joint; and concrete 6 that fills at least part of the gap 5, which ensures performance as a perforated lap joint. Each floor slab has a main body 21, and a projecting part 22 projecting downward from the main body 21 at the connecting part 8 of the pair of the floor slabs. The main body 21 and the projecting part 22 of a pair of floor slabs 2A, and 2B form the gap 5, and the interval G between the projecting parts 22 of the pair of floor slabs is smaller than the interval G1 between the main bodies 21.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a connection structure of a floor slab and a connection method of a floor slab.

Background Art

[0002] In recent years, a large number of floor slab replacement works such as bridges have been carried out. In the floor slab replacement work, precast floor slabs are sequentially arranged adjacent to each other on site and connected to each other. Patent Document 1 discloses a connection structure of a floor slab in which a reinforcing bar joint is formed in a gap between adjacent floor slabs, and the gap is filled with filling concrete. Patent Document 2 discloses a connection structure of a floor slab provided with a protruding portion (also called a chin) that protrudes horizontally at the lower end of the end face of the floor slab. During construction, two floor slabs are arranged so that the protruding portions face each other at a minute interval.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The connection structure of the floor slab disclosed in Patent Document 1 can easily secure a gap of a certain dimension or more in the thickness direction of the floor slab, and thus has excellent filling property of concrete. However, a formwork for closing the lower end of the gap is required when placing the concrete, which affects the workability. The connection structure of the floor slab disclosed in Patent Document 2 does not require a formwork, but since the lower part of the gap becomes narrow, it may be disadvantageous in terms of the filling property of concrete.

[0005] An object of the present invention is to provide a connection structure of a floor slab excellent in workability and filling property of concrete.

Means for Solving the Problems

[0006] The floor slab connection structure of the present invention comprises a pair of precast floor slabs, a linearly extending reinforcing bar joint provided in the gap between the pair of floor slabs and forming an overlapping joint, and a joint that fills at least a portion of the gap. Contains fine aggregate including ferronickel slag and coarse aggregate. It has concrete and a main body and a protruding part that extends downward from the main body at the connection point between a pair of floor slabs. The main body and the protruding part of a pair of floor slabs form the above-mentioned gap, and the distance between the protruding parts of a pair of floor slabs is smaller than the distance between the main bodies. The protruding portion has an upper portion that is closer to the opposing floor slab than the main body portion, and a lower portion that is closer to the opposing floor slab than the upper portion. The gaps between the main bodies of the pair of floor slabs and between the upper portions are filled with concrete. The end faces of the upper portions that face the opposing floor slab are inclined such that the lower end is closer to the opposing floor slab than the upper end. The main bodies of the pair of floor slabs have opposing vertical surfaces, and the distance between the upper ends of the upper portions of the pair of floor slabs is smaller than the distance between the vertical surfaces. [Effects of the Invention]

[0007] According to the present invention, a floor slab connection structure with excellent workability and concrete filling properties can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a deck slab to which the present invention is applied. [Figure 2] This is a schematic diagram of a floor slab connection structure according to one embodiment of the present invention. [Figure 3] This is a schematic diagram of the connection structure of the deck slab in the comparative example. [Figure 4] This is a schematic diagram showing the construction method for connecting the deck slabs. [Modes for carrying out the invention]

[0009] The following describes embodiments of the slab connection structure 1 and slab connection method of the present invention with reference to the drawings. In the following description, the direction in which the steel girder extends, i.e., the longitudinal direction of the steel girder, is referred to as the longitudinal direction X, and the dimension in the width direction of the steel girder is referred to as the girder width direction Y. The longitudinal direction X coincides with the arrangement direction of adjacent slabs and the direction in which the road surface formed by the slabs extends. The longitudinal direction X and the girder width direction Y are orthogonal, and normally, the longitudinal direction X and the girder width direction Y are orthogonal to the vertical direction Z.

[0010] Figure 1 is a schematic diagram of a deck slab 2 to which the present invention is applied. Figure 1(a) is a cross-sectional view taken from the girder width direction Y, and Figure 1(b) is a cross-sectional view taken from the girder length direction X (a cross-sectional view along line AA in Figure 1(a)). The deck slab 2 is installed on top of a steel girder 3 such as a bridge. The deck slab 2 has a rectangular shape with a long side and a short side when viewed from the vertical direction Z. The length of the deck slab 2 in the girder length direction X is approximately 1.5 to 2.5 m. The deck slab 2 is made of precast metal and is manufactured in advance at a factory and then transported to the site.

[0011] Figure 2(a) is a lateral cross-sectional view showing the joint structure 1 of a pair of floor slabs 2 (hereinafter referred to as the first floor slab 2A and the second floor slab 2B), and Figure 2(b) is a plan view seen from above in the Z direction. In Figure 2(b), the reinforcement bar splice 4 is shown for convenience. The basic configuration of the first floor slab 2A and the second floor slab 2B is the same. Therefore, the following explanation will focus on the first floor slab 2A, and the second floor slab 2B will be described mainly for its configuration that differs from that of the first floor slab 2A.

[0012] A gap 5 in the longitudinal direction X is formed between the first slab 2A and the second slab 2B, and the gap 5 is filled with infill concrete 6. The infill concrete 6 is made of a material that can ensure performance as a linear lap joint (for example, a material containing fine aggregate and coarse aggregate with ferronickel slag, with a compressive strength of 160 N / mm²). 2(Concrete) is used. In the drawing, the range of the gap 5 and the range of the infill concrete 6 are substantially the same. The upper surface of the infill concrete 6 forms part of the road surface, and is therefore aligned with the upper surface of the first and second deck slabs 2A and 2B in the Z direction. From the side surface 7A of the first deck slab 2A facing the second deck slab 2B, the upper reinforcement 41 and lower reinforcement 42 extend in the longitudinal direction X. The upper reinforcement 41 and lower reinforcement 42 overlap when viewed from the vertical direction Z. The upper reinforcement 41 and lower reinforcement 42 extend linearly in the longitudinal direction X within the gap 5. From the side surface 7B of the second deck slab 2B facing the first deck slab 2A, the upper reinforcement 41 and lower reinforcement 42 also extend in the longitudinal direction X. The upper and lower reinforcement bars 41 and 42 of the first slab 2A and the upper and lower reinforcement bars 41 and 42 of the second slab 2B are positioned offset from each other by half the reinforcement pitch length in the girder width direction Y (overlap splice). This avoids interference between the reinforcement bars, and a reinforcement splice 4 is provided in the gap 5 between the first slab 2A and the second slab 2B. The reinforcement bars of the first slab 2A (upper and lower reinforcement bars 41 and 42) and the reinforcement bars of the second slab 2B (upper and lower reinforcement bars 41 and 42) overlap by a predetermined length in the girder direction X. This length is the splice length L of the reinforcement splice 4, and in one example it is about 7.5 times the diameter of the reinforcement bar.

[0013] The first slab 2A has a main body 21, a protruding portion 22, and a haunch 23. The main body 21 of the first slab 2A and the second slab 2B, and the protruding portions 22 of the first slab 2A and the second slab 2B form a gap 5. The main body 21 is a roughly rectangular parallelepiped structure whose upper surface forms the road surface. Of the side surface 7A of the first slab 2A, the portion 24 where the main body 21 faces the second slab 2B (the opposing slab) is generally a vertical plane, but it curves gently at the connection point with the protruding portion 22. The upper reinforcement 41 and lower reinforcement 42 penetrate the vertical plane of portion 24 of the side surface 7A. The haunch 23 is a strip-shaped portion that protrudes downward from the lower surface 28 of the main body 21 and extends in the longitudinal direction X. The haunch 23 is fixed to the steel girder 3 and distributes the weight of the first deck slab 2A to the steel girder 3. The cross-section of the haunch 23, viewed in the longitudinal direction X, is a trapezoidal shape with the top side longer than the bottom side, and the bottom surface is flat.

[0014] The protruding portion 22 is the connection portion 8 between the first deck slab 2A and the second deck slab 2B, and protrudes downward from the main body 21. The haunch 23 and the protruding portion 22 are integrated with the main body 21. The lower surface of the haunch 23 and the lower surface of the protruding portion 22 are at the same height, which improves manufacturability in the factory. The protruding portion 22 extends in the girder width direction Y, and the lower surface of the protruding portion 22 is flat.

[0015] A mesh sheet 43 is provided along the lower surface 28 of the main body 21 and the side surface 29 of the protruding portion 22 to prevent the peeling of concrete fragments. The mesh sheet 43 is made of, for example, aramid. The mesh sheet 43 may be attached to the lower surface 28 of the main body 21 and the side surface 29 of the protruding portion 22, but it is preferable to embed it in the concrete structure at a position slightly inside from the lower surface 28 of the main body 21 and the side surface 29 of the protruding portion 22. This allows the mesh sheet 43 to be incorporated into the first floor slab 2A at the factory, eliminating the need to attach the mesh sheet 43 on site.

[0016] The protruding portion 22 has an upper portion 25 that is closer to the second slab 2B (the opposing slab) than the main body portion 21 in the longitudinal direction X, and a lower portion 26 that is closer to the second slab 2B (the opposing slab) than the upper portion 25 in the longitudinal direction X. The protruding portion 22 is provided so as a whole it protrudes diagonally downward from near the connection portion 8 on the lower surface 28 of the main body portion 21. The end face 27 of the upper portion 25 that faces the second slab 2B (the opposing slab) is inclined such that the lower end 272 is closer to the second slab 2B (the opposing slab) than the upper end 271. As a result, the cross-sectional shape of the gap created by the upper portion 25 of the first and second slabs 2A and 2B is roughly similar to a trapezoid when viewed in the girder width direction Y, with the top side being longer than the bottom side.

[0017] The lower surface 28 of the main body 21 and the side surface 29 of the protruding portion 22 are connected by a curve. In one example, the curvature R of the curve is approximately 100 mm. This makes it possible to alleviate stress concentration near the boundary between the lower surface 28 of the main body 21 and the side surface 29 of the protruding portion 22.

[0018] Here, the effects of this embodiment will be described by comparing this embodiment with comparative examples. In Comparative Example 1 shown in Fig. 3(a), the cross-section of the gap 5 in the digit width direction Y is generally rectangular. Therefore, the fit of the reinforcing bar joint 4 and the filling property of the grouting concrete 6 are good. However, when placing the grouting concrete 6, a formwork 51 is required at the lower part of the gap 5. The work of installing the formwork 51 needs to be carried out on-site, and since the formwork 51 is below the floor slab 2, the workability is poor. In this embodiment, the minimum distance between the protruding portions 22 of the first floor slab 2A and the second floor slab 2B is determined by the width of the gap G, and is much smaller than the distance G1 between the main body portions 21. Also, since the gap G is filled with the buffer material 30, there is no need to provide a formwork.

[0019] In Comparative Example 2 shown in Fig. 3(b), a horizontally extending protruding portion 52 (jaw) is provided at the lower ends of the opposing edges of the main body portions 121 of the first floor slab 2A and the second floor slab 2B. The lower surface of the protruding portion 52 coincides with the lower surface of the first floor slab 2A, and the protruding portion 52 does not protrude downward from the main body portion 121 as in this embodiment. In Comparative Example 2, similar to this embodiment, since the lower end of the gap 5 is substantially closed, a formwork is not required. However, since the protruding portion 52 is provided on the side of the main body portion 121, the dimension of the gap 5 in the vertical direction Z has decreased. In this embodiment, since the protruding portion 22 is provided so as to protrude downward from the main body portion 21, a space comparable to that in Comparative Example 1 can be secured on the side of the main body portion 21, that is, in the region where the reinforcing bar joint 4 is formed.

[0020] Also, conventional floor slabs such as those in Comparative Examples 1 and 2 have a thickness of about 220 mm, but in this embodiment, by providing the protruding portion 22 that protrudes downward from the main body portion 21, it is possible to reduce the floor slab thickness (the thickness of the main body portion 21) to about 190 mm. This not only enables a reduction in the amount of the floor slab but also reduces the need for reinforcement of the substructure such as the steel girder 3.

[0021] Next, with reference to Figure 4, the method for joining the deck slabs will be explained. In Figures 4(a) to 4(c), the upper diagram is a lateral cross-sectional view corresponding to Figure 2(a), and the lower diagram is a plan view corresponding to Figure 2(b). Assume that the first deck slab 2A is already installed on the steel girder 3, and the following explanation will describe the process of connecting the second deck slab 2B to the first deck slab 2A. First, as shown in Figure 4(a), the second deck slab 2B is lifted by erection machinery such as a crane (not shown) and positioned to the side of the first deck slab 2A in the longitudinal direction X. A buffer material 30 is attached to the surface of the lower part 26 of the first deck slab 2A that faces the second deck slab 2B. Next, as shown in Figure 4(b), the second deck slab 2B is gradually moved in the longitudinal direction X using erection machinery and positioned adjacent to the first deck slab 2A. Specifically, the lower portion 26 of the second slab 2B is pressed against the buffer material 30, and the second slab 2B is positioned so that there is a predetermined gap G between the lower portions 26 of the first slab 2A and the second slab 2B. Since the reinforcing bars of the first slab 2A and the second slab 2B are offset by half a pitch from each other, the reinforcing bars of the second slab 2B fit between the reinforcing bars of the first slab, and a reinforcing bar joint 4 is formed in the gap 5 between the first slab 2A and the second slab 2B. Next, as shown in Figure 4(c), the gap 5 is filled with concrete 6. This completes the process of joining the second slab 2B to the first slab 2A. After that, mortar is injected between the second slab 2B and the steel girder 3 to fix the second slab 2B to the steel girder 3. Furthermore, prestress may be applied to the first slab 2A and the second slab 2B as needed.

[0022] Although the present invention has been described above with reference to embodiments, the present invention is not limited to the embodiments described above. For example, in the embodiment, the first slab 2A and the second slab 2B are arranged adjacent to each other in the longitudinal direction X, and the slab connection structure 1 extends between the first slab 2A and the second slab 2B along the girder width direction Y. However, the first slab 2A and the second slab 2B may be arranged adjacent to each other in the girder width direction Y. In this case, the slab connection structure 1 extends between the first slab 2A and the second slab 2B along the longitudinal direction X. Such a slab configuration can also be considered as dividing a single slab 2 in the embodiment into sections in the girder width direction Y, and the slab connection structure 1 is provided between slabs adjacent to each other in the longitudinal direction X and between slabs adjacent to each other in the girder width direction Y. [Explanation of symbols]

[0023] 1. Connection structure of the floor slab 2A First floor slab 2B Second floor slab (opponent's floor slab) 3 steel girder 4. Reinforcement bar joints 6. Concrete 8. Connection section of the floor slab 21 Main body 22 Protruding part 23 Hunch 25 Upper part 26 Lower part 43 Mesh Sheet G interval

Claims

1. A pair of precast floor slabs, A linearly extending reinforcing bar joint is provided in the gap between the pair of floor slabs and forms an overlapping joint, The concrete comprises filling at least a portion of the aforementioned gap and containing fine aggregate including ferronickel slag and coarse aggregate, Each floor slab has a main body and a protruding portion that extends downward from the main body at the connection point between the pair of floor slabs. The main body portion and the protruding portion of the pair of floor slabs form the gap. The distance between the protruding portions of the pair of floor slabs is smaller than the distance between the main body portions. The protruding portion has an upper portion that is closer to the opposing floor slab than the main body portion, and a lower portion that is closer to the opposing floor slab than the upper portion, and the gap between the main bodies of the pair of floor slabs and between the upper portions is filled with concrete. The end face of the upper portion facing the opposing floor slab is inclined such that its lower end is closer to the opposing floor slab than its upper end. A floor slab connection structure wherein the main body portions of the pair of floor slabs have opposing vertical surfaces, and the distance between the upper ends of the upper portions of the pair of floor slabs is smaller than the distance between the vertical surfaces.

2. The floor slab connection structure according to claim 1, wherein the lower surface of the main body and the side surface of the protruding part are connected by a curve.

3. The floor slab connection structure according to claim 2, wherein a mesh sheet is provided along the lower surface of the main body and the side surface of the protruding portion.

4. The floor slab connection structure according to claim 1, wherein the floor slab has a haunch that protrudes downward from the lower surface of the main body between the two ends of the pair of floor slabs in the direction of arrangement, and the lower surface of the haunch and the lower surface of the protruding portion are at the same height.

5. A pair of precast floor slabs are arranged such that a gap is formed in the gap between the pair of floor slabs, and a linearly extending reinforcing bar joint is formed. The method involves filling at least a portion of the aforementioned gap with concrete containing fine aggregate including ferronickel slag and coarse aggregate. Each floor slab has a main body and a protruding portion that extends downward from the main body at the connection point between the pair of floor slabs. The main body portion and the protruding portion of the pair of floor slabs form the gap. The distance between the protruding portions of the pair of floor slabs is smaller than the distance between the main body portions. The protruding portion has an upper portion that is closer to the opposing floor slab than the main body portion, and a lower portion that is closer to the opposing floor slab than the upper portion, and the gap between the main bodies of the pair of floor slabs and between the upper portions is filled with concrete. The end face of the upper portion facing the opposing floor slab is inclined such that its lower end is closer to the opposing floor slab than its upper end. A method for connecting floor slabs, wherein the main bodies of the pair of floor slabs have opposing vertical surfaces, and the distance between the upper ends of the upper portions of the pair of floor slabs is smaller than the distance between the vertical surfaces.

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