Precast floor slab joint structure

Abstract

To provide a joint structure of precast floor slabs that can improve workability.SOLUTION: A precast floor slab joint structure 1 includes a pair of precast floor slabs 2A, 2B and a joint part 4, the precast floor slabs 2A, 2B have concrete parts 20 and reinforcing bars 31, the joint part 4 has a reinforcing bar protrusion part 40 protruding from the joint end surface 21 of the reinforcing bars 31, and a joint concrete part 48 in which the reinforcing bar protrusion part 40 is embedded, the reinforcing bar protrusion part 40 has a reinforcing bar base 41 formed with the same outer diameter along the protruding direction, a reinforcing bar enlarged diameter part 43 that is located closer to the tip in the protruding direction than the reinforcing bar base 41 and has a gradually larger outer diameter toward the tip in the protruding direction, and a reinforcing bar reduced diameter part 44 that is located closer to the tip in the protruding direction than the reinforcing bar enlarged diameter part 43 and has a gradually smaller outer diameter toward the tip in the protruding direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a joining structure of precast floor slabs.

Background Art

[0002] Conventionally, in the replacement work of floor slabs, in the case of a two-lane road, it has been common to completely stop traffic on the lane where the floor slab replacement is carried out and implement oncoming traffic on the opposite lane, which has a great impact on the surrounding traffic and has also contributed to traffic congestion. In addition, the implementation of traffic restrictions incurs a large cost, and labor-saving construction has been desired. Furthermore, depending on the construction site, it has sometimes been difficult to apply the conventional full-section construction floor slab replacement itself.

[0003] Therefore, at present, a semi-section (width division) construction method for floor slabs has been introduced, and a construction method is implemented in which the replacement part of the floor slab is advanced with only lane restrictions without imposing oncoming traffic restrictions. In the floor slab replacement work, a joint perpendicular to the vehicle traveling direction (bridge axis direction) is called a transverse joint, and a joint parallel to the vehicle traveling direction is called a longitudinal joint.

[0004] As a precast floor slab for semi-section construction, a construction method using the precast floor slabs shown in Patent Documents 1 and 2 below has been disclosed. It is a method in which after installing the precast floor slabs divided in the floor slab width direction on the girder, the two divided floor slabs are horizontally tightened in the width direction by post-tensioning.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the construction methods of the precast floor slabs disclosed in Patent Documents 1 and 2, there is a problem that the tension work using jacks at narrow bridge ends places a large burden on the workers.

[0007] Therefore, the present invention has been made in view of the above circumstances, and provides a joint structure for precast floor slabs that can improve workability.

Means for Solving the Problems

[0008] To achieve the above object, the present invention employs the following means. That is, the joint structure of the precast floor slab according to the present invention includes a pair of precast floor slabs arranged adjacent to each other with a gap therebetween, and a joint portion disposed in the gap. The precast floor slab has a concrete portion and reinforcing bars embedded in the concrete portion and protruding from the joint end faces facing the sides of the adjacent precast floor slabs in the concrete portion. The joint portion has a reinforcing bar protruding portion protruding from the joint end face of the reinforcing bar and a joint concrete portion for embedding the reinforcing bar protruding portion. The reinforcing bar protruding portion has a reinforcing bar base portion formed with the same outer diameter over the protruding direction, a reinforcing bar diameter-expanded portion located on the tip side in the protruding direction with respect to the reinforcing bar base portion and having an outer diameter gradually increasing toward the tip side in the protruding direction, and a reinforcing bar diameter-reduced portion located on the tip side in the protruding direction with respect to the reinforcing bar diameter-expanded portion and having an outer diameter gradually decreasing toward the tip side in the protruding direction.

[0009] In the joint structure of the precast floor slab configured as described above, reinforcing bar protruding portions are provided on each of the pair of precast floor slabs, and in-situ concrete is placed between the precast floor slabs to construct the joint portion. Therefore, since post-tensioning lateral tightening is unnecessary, the work at narrow locations is reduced and PC connectors are not required. Thus, jointing with a thin floor slab thickness becomes possible, and workability is improved.

[0010] In addition, in the joining structure of the precast floor slab according to the present invention, the joined concrete part may be formed of fiber-reinforced concrete.

[0011] Further, in the joining structure of the precast floor slab according to the present invention, by combining the reinforcing bar protruding part having the reinforcing bar enlarged diameter part and the reinforcing bar reduced diameter part and the fiber-reinforced concrete, a joint part having performance equivalent to integral casting is realized.

Advantages of the Invention

[0012] According to the joining structure of the precast floor slab according to the present invention, constructability can be improved.

Brief Description of the Drawings

[0013]

Figure 1

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Best Mode for Carrying Out the Invention

[0014] Hereinafter, the joint structure of the precast floor slab according to the embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the joint structure 1 of the precast floor slab according to the present embodiment is provided on a bridge and is a joint structure of a pair of precast floor slabs 2A and 2B adjacent to each other in the bridge axis direction. In the following description, the bridge axis direction is denoted as the bridge axis direction Y, and the direction perpendicular to the bridge axis direction is denoted as the direction perpendicular to the bridge axis X.

[0015] In the joint structure 1 of the precast floor slab, the precast floor slabs 2A and 2B are joined via a joint portion 4 provided therebetween. The joint structure 1 of the precast floor slab includes a pair of precast floor slabs 2A and 2B and a joint portion 4. The joint portion 4 is a so-called horizontal joint formed between the precast floor slabs 2A and 2B adjacent to each other in the bridge axis direction Y.

[0016] Hereinafter, the pair of precast floor slabs 2A and 2B may be collectively referred to as the precast floor slab 2.

[0017] The precast floor slabs 2A and 2B are arranged adjacent to each other with a gap S1 in the bridge axis direction Y. The precast floor slabs 2A and 2B each have a concrete portion 20, longitudinal reinforcing bars 31 in the bridge axis direction, and transverse reinforcing bars 32 in the direction perpendicular to the bridge axis.

[0018] The concrete portion 20 is formed in a plate shape. The plate surface of the concrete portion 20 faces the vertical direction. The concrete portion 20 of the precast floor slab 2A and the concrete portion 20 of the precast floor slab 2B are arranged with a gap S1 in the bridge axis direction Y. The joint portion 4 is provided in the gap S1 between the concrete portion 20 of the precast floor slab 2A and the concrete portion 20 of the precast floor slab 2B.

[0019] As shown in FIG. 1, the joint end face 21, which is the end face in the bridge axis direction Y of the concrete part 20, faces the concrete part 20 side of the adjacent precast floor slab 2. The joint end face 21 has an upper vertical face 21a, an upper inclined face 21b, an intermediate vertical face 21c, a lower inclined face 21d, and a lower vertical face 21e.

[0020] The upper vertical face 21a is formed vertically downward from the upper surface 20u of the concrete part 20. The upper inclined face 21b is inclined with respect to the vertical face so as to be separated from the adjacent precast floor slab 2 as it goes downward from the lower end of the upper vertical face 21a. The intermediate vertical face 21c is formed vertically downward from the lower end of the upper inclined face 21b. The lower inclined face 21d is inclined with respect to the vertical face so as to approach the adjacent precast floor slab 2 as it goes downward from the lower end of the intermediate vertical face 21c. The lower vertical face 21e is formed vertically downward from the lower end of the lower inclined face 21d. The lower end of the lower vertical face 21e reaches the lower surface 20d of the concrete part 20.

[0021] The bridge axis direction reinforcing bars 31 extend in the bridge axis direction Y. A plurality of the bridge axis direction reinforcing bars 31 are arranged at intervals in the direction perpendicular to the bridge axis X in each of the upper and lower parts of the concrete part 20. The bridge axis direction reinforcing bars 31 are embedded in the concrete part 20.

[0022] The length dimension in the bridge axis direction Y of the bridge axis direction reinforcing bars 31 is longer than the length dimension in the bridge axis direction Y of the concrete part 20. The bridge axis direction reinforcing bars 31 protrude in the bridge axis direction Y from the joint end face 21 of the concrete part 20.

[0023] The vertical position of the bridge axis direction reinforcing bars 31 arranged on the upper side corresponds to the vertical position of the upper vertical face 21a of the concrete part 20. The bridge axis direction reinforcing bars 31 arranged on the upper side protrude from the upper vertical face 21a. Note that the vertical position of the bridge axis direction reinforcing bars 31 arranged on the upper side can be set as appropriate.

[0024] The vertical position of the longitudinal reinforcing bars 31 arranged on the lower side corresponds to the vertical position of the lower vertical surface 21e of the concrete part 20. The longitudinal reinforcing bars 31 arranged on the lower side protrude from the lower vertical surface 21e. Note that the vertical position of the longitudinal reinforcing bars 31 arranged on the lower side can be set as appropriate.

[0025] The part of the longitudinal reinforcing bars 31 that protrudes from the joint end face 21 of the concrete part 20 is denoted as the reinforcing bar protruding part 40. The longitudinal reinforcing bars 31 correspond to the reinforcing bars in the claims.

[0026] The transverse reinforcing bars 32 extend in the direction perpendicular to the bridge axis X. A plurality of transverse reinforcing bars 32 are arranged at intervals in the longitudinal direction Y of the bridge axis at the upper and lower parts of the concrete part 20 respectively. The transverse reinforcing bars 32 arranged on the upper side are arranged below the longitudinal reinforcing bars 31 arranged on the upper side. The transverse reinforcing bars 32 arranged on the lower side are arranged above the longitudinal reinforcing bars 31 arranged on the lower side. Note that the vertical position of the transverse reinforcing bars 32 can be set as appropriate. The transverse reinforcing bars 32 are reinforcing bars.

[0027] The joint part 4 has a reinforcing bar protruding part 40 and a joint concrete part 48. The reinforcing bar protruding part 40 has a reinforcing bar base part 41 and a reinforcing bar tip part 42.

[0028] The outer diameter of the reinforcing bar base part 41 is formed by the outer diameter of the longitudinal reinforcing bars 31 embedded in the concrete part 20. The outer diameter of the reinforcing bar base part 41 is the same outer diameter over the protruding direction protruding from the joint end face 21 of the concrete part 20.

[0029] As shown in FIG. 3, the reinforcing bar tip part 42 has a reinforcing bar diameter-expanded part 43 and a reinforcing bar diameter-reduced part 44. The reinforcing bar diameter-expanded part 43 is formed continuously with the reinforcing bar base part 41. The reinforcing bar diameter-expanded part 43 is located on the tip part side in the protruding direction with respect to the reinforcing bar base part 41. The reinforcing bar diameter-expanded part 43 is formed such that the outer diameter gradually increases toward the tip part side in the protruding direction.

[0030] The reduced-diameter portion 44 of the reinforcing bar is formed continuously with the enlarged-diameter portion 43 of the reinforcing bar. The reduced-diameter portion 44 of the reinforcing bar is located on the tip side in the protruding direction relative to the enlarged-diameter portion 43 of the reinforcing bar. The reduced-diameter portion 44 of the reinforcing bar is formed such that the outer diameter gradually decreases toward the tip side in the protruding direction.

[0031] As shown in FIG. 4, let the bar diameter (outer diameter of the reinforcing bar) of the bar base portion 41 be D. Note that the bar diameter of the bridge-axis direction reinforcing bar 31 is also D. Let the length in the bridge-axis direction Y of the bar tip portion 42 be L. L is the length from the rear end portion in the protruding direction of the enlarged-diameter portion 43 of the reinforcing bar to the tip end portion in the protruding direction of the reduced-diameter portion 44 of the reinforcing bar. Let the maximum value of the outer diameter of the bar tip portion 42 be H. H is the outer diameter of the boundary portion between the enlarged-diameter portion 43 and the reduced-diameter portion 44 of the reinforcing bar. Let the angle formed by the outer peripheral surface of the enlarged-diameter portion 43 and the plane along the direction perpendicular to the bridge axis X be R1. Let the angle formed by the outer peripheral surface of the reduced-diameter portion 44 and the plane along the bridge-axis direction Y be R2.

[0032] It is preferable to satisfy the following relationships. ·H = 1.5D to 1.7D ·L = 1.5D to 2.5D ·0° ≤ R1 ≤ 60° ·1° ≤ R2 ≤ 15°

[0033] As shown in FIG. 2, at the joint portion 4, the bar protruding portions 40 of the precast floor slab 2A and the bar protruding portions 40 of the precast floor slab 2B are alternately arranged with a gap in the direction perpendicular to the bridge axis X. The bar protruding portions 40 of the precast floor slab 2A and the bar protruding portions 40 of the precast floor slab 2B are arranged overlappingly when viewed from the direction perpendicular to the bridge axis X. The bar protruding portions 40 of the precast floor slab 2A and the bar protruding portions 40 of the precast floor slab 2B are not directly joined to each other. The bar tip portions 42 of the bar protruding portions 40 of the precast floor slab 2A are adjacent to the bar base portions 41 of the precast floor slab 2B with a gap in the direction perpendicular to the bridge axis X. The bar tip portions 42 of the bar protruding portions 40 of the precast floor slab 2B are adjacent to the bar base portions 41 of the precast floor slab 2A with a gap in the direction perpendicular to the bridge axis X.

[0034] As shown in FIG. 1, the length from the tip of the reinforcing bar protruding portion 40 protruding from the precast floor slab 2A to the tip of the reinforcing bar protruding portion 40 protruding from the precast floor slab 2B is referred to as the joint length B. The joint length B is preferably 15D or more.

[0035] As shown in FIG. 1, in the joint portion 4, the reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion are arranged. The reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion extend in the direction X perpendicular to the bridge axis. A plurality of the reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion are arranged at intervals in the bridge axis direction Y at the upper and lower portions of the joint portion 4, respectively. The upper reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion are arranged below the upper reinforcing bar protruding portion 40. The upper reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion are arranged at substantially the same height as the upper reinforcing bars 32 in the direction perpendicular to the bridge axis. The lower reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion are arranged above the lower reinforcing bar protruding portion 40. The lower reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion are arranged at substantially the same height as the lower reinforcing bars 32 in the direction perpendicular to the bridge axis. The vertical position of the reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion can be set as appropriate. The reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion are reinforcing bars.

[0036] The joint concrete portion 48 is filled in the entire gap S1 between the concrete portion 20 of the precast floor slab 2A and the concrete portion 20 of the precast floor slab 2B. The end surface of the joint concrete portion 48 in the bridge axis direction Y abuts between the joint end surface 21 of the precast floor slab 2A and the joint end surface 21 of the precast floor slab 2B. The joint concrete portion 48 is formed in a plate shape with the plate surface facing in the vertical direction by cast-in-place packing concrete. The reinforcing bar protruding portion 40 and the reinforcing bars 46 in the direction perpendicular to the bridge axis of the joint portion are embedded in the joint concrete portion 48.

[0037] The joint concrete portion 48 is preferably normal concrete having a design standard strength of 50 N / mm 2 or more.

[0038] Next, the precast floor slab joint structure 1X for joining a pair of precast floor slabs 2, 2 adjacent to each other in the direction X perpendicular to the bridge axis will be mainly described with reference to FIGS. 5 and 6. In this case, the joint 4X is a so-called longitudinal joint formed between the precast floor slabs 2, 2 adjacent to each other in the direction X perpendicular to the bridge axis. In the description of the precast floor slab joint structure 1X, the same components as those of the precast floor slab joint structure 1 described above will be denoted by the same reference numerals and the description thereof will be omitted.

[0039] The precast floor slab joint structure 1X includes a pair of precast floor slabs 2C, 2D and a joint 4X. The precast floor slabs 2C, 2D are arranged adjacent to each other with a gap S2 therebetween in the direction X perpendicular to the bridge axis. Each precast floor slab 2 has a concrete portion 20, a reinforcing bar 32 in the direction perpendicular to the bridge axis, and a reinforcing bar 31 in the bridge axis direction.

[0040] The concrete portion 20 is formed in a plate shape. The plate surface of the concrete portion 20 faces in the vertical direction. The concrete portions 20 of the precast floor slabs 2C and 2D are arranged with a gap S2 therebetween in the direction X perpendicular to the bridge axis. A joint 4X is provided in the gap S2 between the concrete portions 20 of the precast floor slabs 2C and 2D.

[0041] As shown in FIG. 5, the joint end surface 21X, which is the end surface of the concrete portion 20 in the direction X perpendicular to the bridge axis, faces the concrete portion 20 side of the adjacent precast floor slab 2. The joint end surface 21X has an upper vertical surface 21f, an upper inclined surface 21g, an intermediate vertical surface 21h, a lower inclined surface 21i, and a lower vertical surface 21j.

[0042] The upper vertical surface 21f is formed vertically downward from the upper surface 20u of the concrete part 20. The upper inclined surface 21g is inclined with respect to the vertical surface so as to be separated from the adjacent precast floor slab 2 as it goes downward from the lower end of the upper vertical surface 21f. The middle vertical surface 21h is formed vertically downward from the lower end of the upper inclined surface 21g. The lower inclined surface 21i is inclined with respect to the vertical surface so as to approach the adjacent precast floor slab 2 as it goes downward from the lower end of the middle vertical surface 21h. The lower vertical surface 21j is formed vertically downward from the lower end of the lower inclined surface 21i. The lower end of the lower vertical surface 21j reaches the lower surface 20d of the concrete part 20.

[0043] The reinforcing bars 32 perpendicular to the bridge axis extend in the direction X perpendicular to the bridge axis. A plurality of the reinforcing bars 32 perpendicular to the bridge axis are arranged at intervals in the bridge axis direction Y in each of the upper and lower parts of the concrete part 20. The reinforcing bars 32 perpendicular to the bridge axis are embedded in the concrete part 20.

[0044] The length dimension of the reinforcing bars 32 perpendicular to the bridge axis in the direction X perpendicular to the bridge axis is longer than the length dimension of the concrete part 20 in the direction X perpendicular to the bridge axis. The reinforcing bars 32 perpendicular to the bridge axis protrude in the direction X perpendicular to the bridge axis from the joint end face 21X of the concrete part 20.

[0045] The vertical position of the reinforcing bars 32 perpendicular to the bridge axis arranged on the upper side corresponds to the vertical position of the upper inclined surface 21g of the concrete part 20. The reinforcing bars 32 perpendicular to the bridge axis arranged on the upper side protrude from the upper inclined surface 21g. Note that the vertical position of the reinforcing bars 32 perpendicular to the bridge axis arranged on the upper side can be set as appropriate.

[0046] The vertical position of the reinforcing bars 32 perpendicular to the bridge axis arranged on the lower side corresponds to the vertical position of the lower inclined surface 21i of the concrete part 20. The reinforcing bars 32 perpendicular to the bridge axis arranged on the lower side protrude from the lower inclined surface 21i. Note that the vertical position of the reinforcing bars 32 perpendicular to the bridge axis arranged on the lower side can be set as appropriate.

[0047] The portion protruding from the joint end face 21X of the concrete part 20 in the transverse reinforcement 32 perpendicular to the bridge axis is denoted as the reinforcement protruding part 40. The transverse reinforcement 32 perpendicular to the bridge axis corresponds to the reinforcement in the claims.

[0048] The longitudinal reinforcement 31 extends in the longitudinal direction Y of the bridge axis. A plurality of longitudinal reinforcements 31 are arranged at intervals in the transverse direction X perpendicular to the bridge axis at the upper and lower parts of the concrete part 20, respectively. The longitudinal reinforcement 31 arranged on the upper side is arranged above the transverse reinforcement 32 arranged on the upper side. The longitudinal reinforcement 31 arranged on the lower side is arranged below the transverse reinforcement 32 arranged on the lower side. Note that the vertical position of the longitudinal reinforcement 31 can be set as appropriate. The longitudinal reinforcement 31 is a reinforcing bar.

[0049] The joint part 4X has a reinforcement protruding part 40 and a joint concrete part 48X. The reinforcement protruding part 40 has a reinforcement base part 41 and a reinforcement tip part 42.

[0050] The outer diameter of the reinforcement base part 41 is formed by the outer diameter of the transverse reinforcement 32 embedded in the concrete part 20. The outer diameter of the reinforcement base part 41 is the same outer diameter over the protruding direction protruding from the joint end face 21X of the concrete part 20.

[0051] As shown in FIG. 6, in the joint part 4X, the reinforcement protruding parts 40 of the precast floor slab 2C and the reinforcement protruding parts 40 of the precast floor slab 2D are arranged alternately at intervals in the longitudinal direction Y of the bridge axis. The reinforcement protruding parts 40 of the precast floor slab 2C and the reinforcement protruding parts 40 of the precast floor slab 2D are arranged overlapping when viewed from the longitudinal direction Y of the bridge axis. The reinforcement protruding parts 40 of the precast floor slab 2C and the reinforcement protruding parts 40 of the precast floor slab 2D are not directly joined to each other. The reinforcement tip part 42 of the reinforcement protruding part 40 of the precast floor slab 2C is adjacent to the reinforcement base part 41 of the precast floor slab 2D with a space in the longitudinal direction Y. The reinforcement tip part 42 of the reinforcement protruding part 40 of the precast floor slab 2D is adjacent to the reinforcement base part 41 of the precast floor slab 2C with a space in the longitudinal direction Y.

[0052] As shown in Fig. 5, joint bars 47 in the bridge axis direction are arranged at the joint part 4X. The joint bars 47 in the bridge axis direction extend in the bridge axis direction Y. A plurality of joint bars 47 in the bridge axis direction are arranged at intervals in the direction perpendicular to the bridge axis X at the upper and lower parts of the joint part 4X respectively. The upper joint bars 47 in the bridge axis direction are arranged above the upper reinforcing bar protrusions 40. The upper joint bars 47 in the bridge axis direction are arranged at substantially the same height as the upper bridge axis direction bars 31. The lower joint bars 47 in the bridge axis direction are arranged below the lower reinforcing bar protrusions 40. The lower joint bars 47 in the bridge axis direction are arranged at substantially the same height as the lower bridge axis direction bars 31. The vertical position of the joint bars 47 in the bridge axis direction can be set as appropriate. The joint bars 47 in the bridge axis direction are reinforcing bars.

[0053] The joint concrete part 48X fills the entire gap S2 between the concrete part 20 of the precast floor slab 2C and the concrete part 20 of the precast floor slab 2D. The end face of the joint concrete part 48X in the direction perpendicular to the bridge axis X abuts between the joint end face 21X of the precast floor slab 2C and the joint end face 21X of the precast floor slab 2D. The joint concrete part 48X is formed in a plate shape with the plate surface facing the vertical direction by in-situ cast infill concrete. The reinforcing bar protrusions 40 and the joint bars 47 in the bridge axis direction are embedded in the joint concrete part 48X.

[0054] The joint concrete part 48X is formed of fiber-reinforced concrete. The joint concrete part 48X is preferably high-strength fiber-reinforced concrete with a design standard strength of 120 N / mm 2 or more and 135 N / mm 2 or less.

[0055] In the case of longitudinal joints, the bars 32 in the direction perpendicular to the bridge axis are D19 - D25. The joint length B is 7.5D - 12.5D, for example 220 mm. Note that the above is an example, and the types and numerical values of the members to be used can be set as appropriate.

[0056] In the joint structure 1, 1X of the precast floor slab, the joint strength is enhanced by the bearing resistance of the enlarged rebar part 43 (see arrow A1 in Fig. 3) and the adhesion of the rebar at the rebar base part 41 (see arrow A2 in Fig. 3).

[0057] Next, a floor slab bending test was conducted on the joint structure (longitudinal joint) 1X of the precast floor slab according to this embodiment. The test specimens are shown in Figs. 7 and 8. D22 or D25 is used for the axial rebars (rebars perpendicular to the bridge axis) of the test specimens (Fig. 8 shows the case of D25).

[0058] As shown in Figs. 9 and 10, regardless of the rebar diameter and joint length, it was confirmed that under the action of the bending moment, it has the same performance as the test specimen of the monolithic RC floor slab without joints. Therefore, by using the joint structure 1 of the precast floor slab according to this embodiment, it is possible to integrate two precast floor slabs without laterally tightening them by post-tensioning. Also, by making the longitudinal joint part an RC structure, when repairing the precast floor slab, compared with the PC structure that affects the entire width, partial repair of only the damaged precast floor slab is possible, so there is an advantage in terms of maintenance management. Furthermore, since the RC structure is easier to arrange the joint reinforcement bars on-site compared with the PC connection method, the construction becomes easier. In addition, the joint structure 1 of the precast floor slab according to this embodiment can also be used in combination with the precast floor slab of the PC connection method to form a hybrid structure using PC joints and RC joints.

[0059] In the joint structure 1 of the precast floor slab configured in this way, rebar protruding parts 40 are provided on a pair of precast floor slabs 2, 2 respectively, and in-situ concrete is placed between the precast floor slabs 2, 2 to construct the joint parts 4, 4X. Therefore, since lateral tightening by post-tensioning is unnecessary, the work in narrow places is reduced and PC connectors are not required. Thus, jointing with a thin floor slab thickness becomes possible and the workability is improved.

[0060] In addition, by adopting a half-section construction method or a segmented construction method with a width of three or more segments, it is possible to perform the slab renewal work only by implementing lane restrictions in the areas around the construction site. Therefore, it is possible to streamline the construction work and reduce the impact on the surrounding traffic.

[0061] In addition, the joint strength is enhanced by the bearing resistance of the enlarged-diameter part 43 of the reinforcing bar and the adhesion of the reinforcing bar at the base part 41 of the reinforcing bar.

[0062] In addition, by combining the reinforcing bar protruding part 40 having the reinforcing bar tip part 42 and the fiber-reinforced concrete, the joint part 4 having the same performance as integral casting is realized.

[0063] In addition, by making the joint part 4 an RC structure, when compared with a PC structure that affects the entire width during the repair of the slab, it is possible to partially repair only the damaged part of the slab. Therefore, an improvement in maintenance management efficiency can be expected.

[0064] In addition, in this embodiment, it is possible to use it in combination with a precast slab of a PC connection method, and a hybrid structure of PC joint and RC joint can be realized.

[0065] In addition, compared with a steel slab or a steel-concrete composite slab, economical construction is possible.

[0066] Note that the various shapes, combinations, etc. of the respective constituent members shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

[0067] For example, in the above-described embodiment, the precast slabs 2A and 2B are provided on the bridge, but they may be provided outside the bridge.

[0068] Among the 17 international goals adopted at the United Nations Summit in September 2015 are the "Sustainable Development Goals (SDGs)". The precast floor slab joint structure 1 according to this embodiment can contribute to the achievement of, for example, the goal of "9. Build the foundation for industry and technological innovation" among the 17 goals of the SDGs.

Explanation of symbols

[0069] 1,1X Joint structure of precast floor slab 2,2A,2B,2C,2D Precast floor slab 4,4X Joint part 20 Concrete part 21,21X Joint end face 31 Rebar in the bridge axis direction (rebar) 40 Rebar protrusion 41 Rebar base 43 Rebar diameter-expanded part 44 Rebar diameter-reduced part 48 Joint concrete part S1,S2 Gap

Claims

1. A pair of precast floor slabs arranged adjacent to each other with a gap therebetween, and a joint portion arranged in the gap, comprising: The precast floor slab has a concrete portion, and reinforcing bars embedded in the concrete portion and protruding from the joint end faces facing the adjacent precast floor slab sides in the concrete portion; The joint portion has a reinforcing bar protruding portion protruding from the joint end face of the reinforcing bar, and a joint concrete portion for embedding the reinforcing bar protruding portion; The reinforcing bar protruding portion has a reinforcing bar base portion formed with the same outer diameter over the protruding direction, a reinforcing bar diameter expanding portion located on the tip side in the protruding direction with respect to the reinforcing bar base portion and having an outer diameter gradually increasing toward the tip side in the protruding direction, and a reinforcing bar diameter reducing portion located on the tip side in the protruding direction with respect to the reinforcing bar diameter expanding portion and having an outer diameter gradually decreasing toward the tip side in the protruding direction. A joint structure of a precast floor slab.

2. The joint structure of a precast floor slab according to Claim 1, wherein the joint concrete portion is formed of fiber-reinforced concrete.

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