JP2021055531A - Floor slab joint structure - Google Patents

Abstract

To propose a floor slab joint structure that enables labor saving during construction and shortens a construction period.SOLUTION: A floor slab joint structure 1 in which reinforcing bars 3 protruding from each of end surfaces 23 of adjacent reinforced concrete precast floor slabs 2 are joined by an empty lap joint is provided. The reinforcing bar 3 is a floor slab vertical reinforcement 21 arranged on the precast floor slab 2, and includes a fiber reinforcement mortar 5 filled in a gap 11 formed between the facing end surfaces 23, and a fixing body 4 made of steel plate fixed to a tip of the reinforcing bar 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to a floor slab joint structure of a concrete precast floor slab.

The continuously laid precast floor slabs are connected to each other via the interstitial concrete, the interstitial mortar, or the like (hereinafter, simply referred to as “interstitial material”) placed in the joint portion.
For example, in Patent Document 1, in a state where the end faces of the precast floor slab on which the loop muscles protrude are butted against each other with a predetermined gap, the force distribution muscles intersecting the loop muscles are arranged in the gaps between the end faces. A floor slab joint structure for placing precast concrete is disclosed. In the joint structure of Patent Document 1, a jaw portion covering the lower surface of the gap is formed in the lower part of the precast floor slab.
However, in the conventional floor slab joint structure, it takes time and effort to arrange the force distribution reinforcement inside the loop reinforcement after laying the precast floor slab. In addition, the precast floor slabs need to be laid with their jaws abutting each other, but if the precast floor slabs come into contact with each other during laying, they may be damaged, so careful work is required. , Skilled skill is required. In addition, since the processing dimensions of the loop streaks are limited, the reduction of the member thickness of the precast floor slab is also limited in consideration of the covering of the loop streaks. Further, due to the size of the loop bar, the gap between the precast floor slabs becomes large, so that the required concrete is increased, the casting work takes time, and the shortening of the construction period is hindered.

Japanese Unexamined Patent Publication No. 2010-236258

An object of the present invention is to propose a floor slab joint structure that enables labor saving during construction and shortens the construction period.

In order to solve such a problem, the present invention is a floor slab joint structure in which reinforcing bars protruding from each other's end faces of floor slabs installed at predetermined intervals are joined by an empty lap joint. A fiber reinforced filler filled between the end faces facing each other and a fixing body formed at the tip of the reinforcing bar are provided.
It is desirable that the reinforcing bars are SD390 or less, the joint length of the empty lap joint is 2.4 times or more the diameter of the reinforcing bars, and the interval between the reinforcing bars is 8 times or less the diameter of the reinforcing bars.
Further, as the fiber reinforced filler, fiber reinforced concrete or fiber reinforced mortar containing cement as a main component may be used, preferably, the design standard strength is 50 N / mm ² or more, and the volume ratio is 0.5%. A fiber reinforced mortar containing the above fibers may be used.
Further, the fixing body may be formed by fixing a circular or rectangular steel plate having an outer diameter or width twice or more the reinforcing bar diameter of the reinforcing bar and a thickness of 12 mm or more to the tip of the reinforcing bar.
Further, it is desirable that the distance between the tip of the reinforcing bar protruding from the end face of one floor slab and the end face of the other floor slab is within the range of 15 mm to 45 mm.
According to such a floor slab joint structure, since the reinforcing bars having the fixing body formed at the tip are arranged, the fixing length of the reinforcing bars can be shortened, and as a result, the gap between the end faces can be reduced. It will be possible. Therefore, the amount of fiber-reinforced mortar filled in the gap is reduced, the time required for the placing work is reduced, and the construction period can be shortened. By using the fiber reinforced mortar as the filling material, the filling material exhibits a high tensile resistance force, so that the force distribution muscle can be omitted. As a result, the labor of arranging the force distribution muscles can be omitted, so that the labor during construction can be reduced. Further, since it is not necessary to consider the bending process of the reinforcing bar, the degree of freedom in setting the thickness of the floor plate is improved.

According to the floor slab joint structure of the present invention, it is possible to save labor during construction and to shorten the construction period.

It is a top view which shows the floor slab joint structure of this embodiment. It is a side view which shows the floor slab joint structure of this embodiment. It is a top view which shows the outline of the test model of the demonstration experiment. It is a graph which shows the relationship between the strain of a reinforcing bar part and a pull-out load in a demonstration experiment. It is a figure which shows the outline of the test body in the demonstration experiment, (a) is a plan view, (b) is a side view. It is a figure which shows the outline of the test body of the comparative example in the demonstration experiment, (a) is a plan view, (b) is a side view. It is a graph which shows the relationship of load-deflection in a demonstration experiment.

In this embodiment, in the construction of a bridge, a floor slab joint structure 1 for joining a plurality of precast floor slabs 2 laid continuously in the bridge axis direction will be described. The floor slab joint structure 1 comprises a pair of precast floor slabs 2 and 2 arranged with a gap 11 and a fiber reinforced mortar 5 filled between the end faces 23 of the precast floor slab 2 (gap 11). I have.

The precast floor slab 2 is made of reinforced concrete. As shown in FIGS. 1 and 2, inside the precast floor slab 2, two upper and lower floor slab vertical bars 21 are arranged along the bridge axis direction (horizontal direction in the drawing), and the floor slab is arranged. The floor slab horizontal bars 22 that intersect the vertical bars 21 are arranged. Further, a reinforcing bar 3 is projected from the end surface 23 of the precast floor slab 2. As shown in FIG. 2, the reinforcing bar 3 of the present embodiment is a portion of the floor slab vertical bar 21 that protrudes from the end face 23 and is arranged in the gap 11. The reinforcing bar 3 of this embodiment is SD345. The reinforcing bar 3 may be planted on the end surface 23 of the precast floor slab 2 separately from the floor slab vertical bar 21.
A shear key 24 is formed on the end surface 23 of the precast floor slab 2 of the present embodiment to improve the transmission of force between the fiber reinforced mortar 5 and the precast floor slab 2. Further, the end face 23 is roughened in order to improve the bondability with the fiber reinforced mortar 5. The shear key 24 is a recess on a trapezoidal cross-section formed near the middle of the reinforcing bars 3 arranged vertically. The shear key 24 of the present embodiment is continuous in the width direction (vertical direction in FIG. 1) of the precast floor slab 2, but the shear key 24 may be formed intermittently. The cross-sectional shape of the shear key 24 is not limited, and may be, for example, a rectangle or a circle. Further, the shear key 24 may be a convex portion formed on the end face 23.

As shown in FIG. 1, in the floor slab joint structure 1, the reinforcing bars 3 protruding from the end surface 23 of one precast floor slab 2 and the reinforcing bars 3 protruding from the end surface 23 of the other precast floor slab 2 are viewed in a plan view. They are arranged alternately. In the present embodiment, the reinforcing bars 3 are arranged so that the reinforcing bars 3 protruding from the end surface 23 of the other precast floor slab 2 are arranged near the middle of the reinforcing bars 3 protruding from the end surface 23 of one precast floor slab 2. Reinforcing bars are arranged. That is, the intervals between the reinforcing bars 3 arranged alternately are equal intervals.
A fixing body 4 is formed at the tip of the reinforcing bar 3. The fixing body 4 of the present embodiment is formed by fixing a rectangular steel plate having a width of 40 × 70 mm (width is at least twice the diameter of the reinforcing bar 3) and a thickness of 12 mm or more to the tip of the reinforcing bar 3. The method of fixing the fixing body 4 to the reinforcing bar 3 is not limited, and may be fixed by, for example, welding, friction welding or gas pressure welding. When the reinforcing bar 3 is threaded, a nut may be used for the reinforcing bar 3 as the fixing body 4, or a steel plate having bolt holes may be used. Further, the fixing body 4 is not limited to the one formed by fixing another member (steel plate) to the reinforcing bar 3, and for example, the enlarged diameter portion formed by compressing the end portion in the axial direction. It may be (so-called bump).

In the floor slab joint structure 1 of the present embodiment, as shown in FIG. 1, the reinforcing bars 3 protruding from the end faces 23 of the pair of precast floor slabs 2 and 2 installed facing each other are joined by an empty lap joint. In the empty lap joint, the ends of the reinforcing bars 3 are stacked in the axial direction with a space between the reinforcing bars 3, and the reinforcing bars 3 are bonded to each other due to the adhesive force between the fiber reinforced mortar 5 (concrete or the like) and the reinforcing bars 3. It forms a state in which the above are joined. The joint length of the empty lap joint is 2.4 times or more, preferably 5 times or more, more preferably 5 times to 15 times the diameter of the reinforcing bar. Further, the reinforcing bar spacing (reinforcing bar arrangement pitch) is 8 times or less the reinforcing bar diameter, preferably within the range of 6 to 8 times the reinforcing bar diameter. The distance between the tip of the reinforcing bar 3 protruding from the end surface 23 of one precast floor slab 2 and the end surface 23 of the other precast floor slab 2 is within a range of 15 mm or more and less than 45 mm, preferably within a range of 15 mm or more and less than 30 mm. Be inside.

Fiber reinforced mortar 5 is filled between the end faces 23 of the adjacent precast floor slabs 2 (gap 11). The design standard strength of the fiber reinforced mortar 5 is 50 N / mm ² or more, and 0.5% or more of fibers are mixed in the volume ratio. In the present embodiment, as the fiber reinforced mortar 5, an early curing type ^{having a strength of 24 / mm 2 for} 3 hours and a strength of 60 N / mm ^{2 for 7 days is used.} The type of the fiber reinforced mortar 5 is not limited to the early curing type, and for example, an ultra-high strength type having ^{a strength of 100 N / mm 2 for 7 days may be used.}

Next, the construction procedure of the floor slab joint structure 1 will be described. First, the precast floor slab 2 is laid. The precast floor slab 2 is laid by arranging one precast floor slab 2 at a predetermined position and then suspending the other precast floor slab 2 from above. At this time, a gap 11 having a predetermined size is formed between the end faces 23 of the adjacent precast floor slabs 2. Further, the reinforcing bars 3 protruding from the end surface 23 of one precast floor slab 2 are arranged between the reinforcing bars 3 protruding from the end surface 23 of the other precast floor slab 2. A fixing body 4 is formed in advance at the tip of the reinforcing bar 3.
After laying the precast floor slab 2, the side surfaces and the bottom surface of the gap 11 are covered with a formwork (not shown) as needed. In addition, when there is no possibility that the fiber reinforced mortar 5 flows out from the lower side of the gap 11, such as when the main girder is arranged on the lower side of the gap 11, the formwork on the bottom surface of the gap 11 is omitted. You may.
After covering the periphery of the gap 11 with a mold, the gap 11 is filled with the fiber reinforced mortar 5. The fiber reinforced mortar 5 is preferably manufactured on-site. The fiber-reinforced mortar 5 is cured, and when a predetermined strength is developed, the mold is removed.

According to the floor slab joint structure 1 of the present embodiment, since the reinforcing bars 3 having the fixing body 4 formed at the tip are arranged, the fixing length of the reinforcing bars 3 can be shortened, and as a result, the precast floor. The gap 11 between the plates 2 (end faces 23) can be reduced. Therefore, the amount of the fiber reinforced mortar 5 filled in the gap 11 can be reduced, the time required for the placement work of the fiber reinforced mortar 5 can be shortened, and the construction period can be shortened.
The reinforcing bar 3 protruding from the end face 23 is straight and does not require bending. Therefore, the cost required for bending the reinforcing bar 3 can be omitted. Further, since it is not necessary to consider the bending process of the reinforcing bar 3, the degree of freedom in setting the thickness is improved, such as reducing the thickness of the precast floor slab 2 to 240 mm or less. By reducing the wall thickness of the precast floor slab 2, the precast floor slab 2 can be easily handled and the amount of fiber reinforced mortar 5 filled in the gap 11 can be reduced, so that the construction period can be shortened. Further, by reducing the amount of the fiber reinforced mortar 5, it is possible to reduce the size of the manufacturing equipment of the fiber reinforced mortar 5 and the labor required for manufacturing the fiber reinforced mortar 5.
Further, since the jaw portion is not formed at the end portion of the precast floor slab 2, it is difficult for the precast floor slabs 2 to come into contact with each other when the precast floor slab 2 is laid. Further, since the precast floor slab 2 to be laid later can be arranged at a predetermined position by suspending it vertically from above, positioning is easy. Therefore, the laying work of the precast floor slab 2 can be easily performed without requiring a skilled technique.

Further, by using the fiber reinforced mortar 5 as the filling material to be filled in the gap 11, the filling material exhibits a high tensile resistance force, so that the force distribution muscle can be omitted. As a result, since it is not necessary to arrange the force distribution bars in the gaps where the intervals are narrow, it is possible to reduce the labor during construction as compared with the conventional joint structure.
Further, even when the fiber reinforced mortar 5 after curing is cracked, the width of the crack is prevented from widening due to the cross-linking effect of the fibers of the fiber reinforced mortar 5, so that the durability is high.
By using a material that cures at an early stage as the fiber reinforced mortar 5, it is possible to perform early construction and eventually to open traffic at an early stage.
Further, the fiber reinforced mortar 5 generally has a large amount of cement, and the cured product has a dense structure, so that it is difficult for substances to permeate and the fiber reinforced mortar 5 exhibits high durability. Further, by mixing an expanding material for compensating for shrinkage, opening or the like is less likely to occur in the gap 11, intrusion of water, oxygen, etc. is reduced, and durability is improved.

Hereinafter, the experimental results of the floor slab joint structure 1 of the present embodiment will be described. First, as shown in FIG. 3, when a tensile force P was applied to the reinforcing bars 3 joined by the empty lap joint in the fiber reinforced mortar 5, it was confirmed that the hardened body of the fiber reinforced mortar 5 was cracked. .. Reference numeral 6 in FIG. 3 is a strain gauge.
(1) Verification of empty lap joint length First, the influence of the empty lap joint length L1 was confirmed. In the experiment, when the empty lap joint length L1 is 95 mm (equivalent to 5D) as the case 1, when the empty lap joint length L1 is 190 mm (equivalent to 10D) as the case 2, the empty lap joint length L1 is 285 mm (equivalent to 10D) as the case 3. A pull-out test was conducted for each case (equivalent to 15D). In each case, experiments were conducted on two test specimens. As the reinforcing bar 3, SD345 and D19 mm were used. A circular steel plate having a diameter of 50 mm and a thickness of 12 mm was fixed to the end of the reinforcing bar 3 as a fixing body 4. As the fiber reinforced mortar 5 (filling material), an early curing type fiber reinforced mortar 5 having ^{a strength of 24 / mm 2 for} 3 hours and a strength of 59.3 N / mm ^{2 for 7 days was used.} The width L2 of the gap 11 of the cases 1 to 3 was 149 mm, 244 mm, and 339 mm, respectively. The reinforcing bar spacing (reinforcing bar arrangement pitch) I of the reinforcing bars 3 was set to 150 mm. The test results are shown in Table 1. Further, FIG. 4 shows the relationship between the strain (reinforcing bar strain) generated in the reinforcing bars of the case 1 (gap width 149 mm), the case 2 (gap width 244 mm) and the case 3 (gap width 339 mm) and the pull-out load. In each of the test bodies (cases 1 to 3), the pull-out test was completed due to the breakage of the screw portion provided on the reinforcing bar 3.

As shown in Table 1, cracks occurred in Case 1 where the empty lap joint length L1 was 5D, but the size of the cracks was as fine as 0.04 mm or less, and the crack generation load was the first and 2nd body. Since both body parts are 70 kN or more, which greatly exceeds the load during operation (reinforcing bar stress during service = 120 N / mm ² → equivalent to the withdrawal load of 34 kN in this test), no practical problem occurs. Further, in cases 2 and 3 in which the empty lap joint lengths L1 were 10D and 15D, no cracks occurred. From the above test, it was confirmed that when the fiber reinforced mortar 5 having a strength of 59.3 N / mm ² or more for 7 days was used, the empty lap joint length L1 should be secured at 5D or more.
Further, as shown in FIG. 4, in any of the cases 1 (gap width 149 mm), case 2 (gap width 244 mm), and case 3 (gap width 339 mm), the maximum reinforcing bar strain is 2000 × ^10-6. It became a value close to. Therefore, the yield point of ^{the reinforcing bar is about 400 N / mm 2} (≈ (2.05 × 10 ⁵ N / mm ² ) × (2000 × ^10-6 )), and it is possible to use the reinforcing bar of substantially SD390. It could be confirmed.

(2) Verification of Reinforcing Bar Spacing Next, the influence of Reinforcing Bar Spacing I was confirmed. In the experiment, the reinforcing bar spacing I of cases 1, 4 and 5 was set to 150 mm, 125 mm and 175 mm, respectively, and the occurrence of cracks was confirmed. Other conditions of cases 4 and 5 (empty lap joint length L1, materials used, etc.) were the same as in case 1. The test results are shown in Table 2.

As shown in Table 2, in Case 5 where the reinforcing bar spacing I was 175 mm, cone-shaped fracture occurred in the first body and cracks of about 0.2 mm occurred in the second body. On the other hand, in Case 1 having a reinforcing bar spacing I of 150 mm and Case 4 having a reinforcing bar spacing I of 125 mm, only fine cracks of 0.04 mm or less occurred. Even in Case 5, the crack generation load is 58 kN or more for both the first and second bodies, ^{which greatly exceeds the load during operation (reinforcing bar stress during service = 120 N / mm 2} → equivalent to the withdrawal load of 34 kN in this test). Therefore, no practical problem occurs. Therefore, when a reinforcing bar 3 (SD345, reinforcing bar diameter 19 mm) to which a circular steel plate having a diameter of 50 mm and a thickness of 12 mm is fixed as the fixing body 4 and an early curing type fiber reinforced mortar 5 is used, the reinforcing bar spacing I is 175 mm or less. However, the result is that 150 mm or less is more desirable.

(3) Verification of Type of Fiber Reinforced Mortar Next, the effect of changing the type of fiber reinforced mortar 5 was confirmed. In the experiment, an early-curing fiber-reinforced mortar 5 having a strength of 24 / mm ^{2 for} 3 hours and a strength of 59.3 N / mm ² for 7 days was used in case 1, and in case 6, the strength was 7 An ultra-high strength type fiber reinforced mortar 5 having a daily strength of 101 N / mm ^{2 was used.} Other conditions of the case 6 (empty lap joint length, gap spacing, reinforcing bars, fixed body, etc.) were the same as those of the case 1. The test results are shown in Table 3.
As shown in Table 3, it was confirmed that when the ultra-high strength type fiber reinforced mortar 5 was used, cracks did not occur even when the empty lap joint length L1 was set to 95 mm.

(4) Verification of the distance between the fixed body and the end face of the precast floor slab Next, the result of confirming the effect of changing the distance between the fixed body 4 and the end face 23 of the precast floor slab 2 is shown. In this experiment, the distance between the fixing body 4 and the end face 23 of the precast floor slab 2 was set to 15 mm in the case 1 and 30 mm in the case 7. In addition, the conditions of the case 7 (empty lap joint length L1, materials used, etc.) were the same as those of the case 1. The test results are shown in Table 4.
As shown in Table 4, when the distance between the fixing body 4 and the end face 23 of the precast floor slab 2 was widened to 30 mm, cone-shaped fracture occurred, but the crack generation load was the first and second bodies. Both are 50 kN or more, which greatly exceeds the load during operation (reinforcing bar stress during service = 120 N / mm ² → equivalent to the withdrawal load of 34 kN in this test), so no practical problem occurs. On the other hand, if the distance between the fixing body 4 and the end face 23 of the precast floor slab 2 is 15 mm or less, it becomes difficult to fill the fiber reinforced mortar 5. Therefore, the distance between the fixing body 4 and the end face 23 of the precast floor slab 2 is preferably in the range of 15 mm to 45 mm, more preferably in the range of 15 mm to 30 mm, and more preferably in the range of about 15 mm.

(5) Verification of Effect of Gap Width and Filling Material Type Next, as shown in FIGS. 5A and 5B, a total length of 3000 mm and a width of 825 mm formed by joining a pair of precast floor slabs 2 Using the test piece, the influence of the gap width and the type of packing material was verified. Specifically, the influence of the gap width and the influence of the filling material type were confirmed based on the relationship between the vertical load Pv and the deflection when the vertical load Pv was applied (bending test).
The vertical load Pv was applied by 1/2 each at a position 400 mm in the longitudinal direction from the center of the test piece. Specimens were supported at two locations 1200 mm longitudinally from the center.
The pair of precast floor slabs 2 are joined by lap joints in the fiber reinforced mortar 5 filled in the gap 11 between the precast floor slabs 2.

In case a, the gap width was set to 100 mm (equivalent to a lap joint length of 2.4D), and in case b, the gap width was set to 150 mm (equivalent to a lap joint length of 5D), and bending tests were performed on each of cases a and b.
In cases a and b, an ultra-high-strength fiber-reinforced mortar 5 having ^{a strength of 101 N / mm 2} for 7 days was used as the filling material. Further, as the reinforcing bar 3, a reinforcing bar having a different diameter of SD345 and D19 mm was used. A circular steel plate having a diameter of 50 mm and a thickness of 12 mm was fixed to the end of the reinforcing bar 3 as a fixing body 4. Further, the reinforcing bar spacing (reinforcing bar arrangement pitch) of the reinforcing bars 3 was set to 150 mm.
Further, in the case c, the gap width is 100 mm (equivalent to the empty lap joint length 2.4D), in the case d, the gap width is 150 mm (equivalent to the empty lap joint length 5D), and in the case e, the gap width is 250 mm (empty). The lap joint length was equivalent to 10D), and bending tests were performed on each of the cases c to e. The During filling material of the case c-e, the intensity at the age of 3 hours 24N / mm ^2, the strength at the age of 7 days was used early curable fiber reinforced mortar 59.3N / mm ^2. Further, as the reinforcing bar 3, the deformed reinforcing bars of SD345 and D19 were used. A circular steel plate having a diameter of 50 mm and a thickness of 12 mm was fixed to the end of the reinforcing bar 3 as a fixing body 4. The reinforcing bar spacing (reinforcing bar arrangement pitch) of the reinforcing bars 3 was set to 150 mm.
Further, as a case f (comparative example), as shown in FIGS. 6A and 6B, the end faces of the precast floor slab 2 on which the loop muscles protrude are butted against each other with a gap width of 340 mm secured. , A bending test was performed on a test body in which reinforcements intersecting with the loop reinforcements were arranged and interstitial concrete was placed in the gap 11 between the end faces. As the padded concrete of the case f, 65.9 N / mm ² concrete was used. Further, as the reinforcing bar 3, the deformed reinforcing bars of SD345 and D19 were used. The place of action of the vertical load Pv of the test piece of case f and the support point of the test piece were the same as those of the test pieces of cases a to e. The length of the lap joint of the loop muscle was 279 mm (equivalent to 14.7D).

Experiments were conducted on one test piece in each case. The test results are shown in Table 5. Further, of case a (gap width 100 mm), case b (gap width 150 mm), case c (gap width 100 mm), case d (gap width 150 mm), case e (gap width 250 mm), case f (gap width 340 mm). The load-deflection relationship is shown in FIG.

As shown in Table 5, in case a, case b, and case f, the PCa portion (precast floor slab 2), not the gap portion, was destroyed, so the test was terminated. The maximum load of case a was 266.9 kN, and the maximum load of case b was 280.4 kN, which exceeded the maximum load of 237.7 kN of case f. Further, as shown in FIG. 6, it was confirmed that the load-deflection relationship between the case a and the case b exceeds the load-deflection relationship of the case f.
As shown in Table 5, in case c, a large crack was generated in the gap and the load was reduced, so that the test was completed. The maximum load was 187.3 kN, which was lower than the maximum load of 237.7 kN in case f.
Further, as shown in Table 5, in case d, case e, and case f, the PCa portion (precast floor slab 2) was destroyed, so that the test was terminated. It was confirmed that the maximum load in case d was 268.8 kN and the maximum load in case e was 280.4 kN, which exceeded the case f. Further, as shown in FIG. 6, the load-deflection relationship between the case d and the case e exceeds the load-deflection relationship of the case f, but the load-deflection relationship of the case c is lower than the load-deflection relationship of the case f.

From the above results, when the ultra-high strength type fiber reinforced mortar 5 having a strength of 101 N / mm ² for 7 days is used as the filling material (cases a and b), the empty lap joint length L1 is set to 2. It was confirmed that if 4D or more is secured, a joint structure having higher strength than the floor slab joint structure using the loop joint can be constructed.
Further, when the fiber reinforced mortar 5 having a strength of 59.3 N / mm ² or more for 7 days is used (cases c to e), if the empty lap joint length is secured to 5D or more (cases d and e), It was confirmed that a joint structure with higher strength than the floor slab joint structure using a loop joint can be constructed.
Although the case c is slightly inferior in strength, it is possible to save labor and shorten the construction period at the time of construction.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and each component can be appropriately modified without departing from the spirit of the present invention.
In the above embodiment, SD345 is used as the reinforcing bar 3, but the standard (yield point) of the reinforcing bar 3 is not limited as long as it is SD390 or less, and may be, for example, SD295.
The reinforcing bar 3 may be coated with a synthetic resin such as an epoxy resin, if necessary. If the reinforcing bar 3 is coated with a resin, the same effect as in the case where the resin coating is not applied can be obtained, and corrosion of the reinforcing bar 3 can be prevented.
The shape of the fixing body 4 is not limited as long as the outer diameter or width is twice or more the diameter of the reinforcing bar 3 and the thickness is 12 mm or more.
In the above embodiment, the intervals between the reinforcing bars 3 protruding from the opposite end faces 23 and alternately arranged are set to be equal intervals, but the intervals between the reinforcing bars 3 protruding from the facing end faces 23 do not necessarily have to be equal intervals. Absent.
The fiber reinforced mortar 5 may be manufactured on-site or may be carried in from a plant outside the site.
Further, the fiber reinforced filler is not limited to the fiber reinforced mortar, and fiber reinforced concrete may be used as long as workability and filling property can be ensured.

1 Floor slab joint structure 11 Gap 2 Precast floor slab 21 Floor slab vertical bar 22 Floor slab horizontal bar 23 End face 24 Shear key 3 Reinforcing bar 4 Fixing body 5 Fiber reinforced mortar (fiber reinforced filler)

Claims (5)

It is a floor slab joint structure in which reinforcing bars protruding from each other's end faces of floor slabs installed at predetermined intervals are joined by an empty lap joint.
A fiber reinforced filler filled between the end faces facing each other,
A floor slab joint structure comprising: a fixing body formed at the tip of the reinforcing bar. The first aspect of the present invention, wherein the reinforcing bars are SD390 or less, the joint length of the empty lap joint is 2.4 times or more the diameter of the reinforcing bars, and the interval between the reinforcing bars is 8 times or less the diameter of the reinforcing bars. Floor slab joint structure. The fiber reinforced filler is a fiber reinforced mortar, which has a design standard strength of 50 N / mm ² or more and contains 0.5% or more fibers in a volume ratio. Item 2. The floor slab joint structure according to item 2. Any one of claims 1 to 3, wherein the anchored body is a circular or rectangular steel plate having an outer diameter or width of twice or more the reinforcing bar diameter of the reinforcing bar and a thickness of 12 mm or more. Floor slab joint structure described in the section. Any one of claims 1 to 4, wherein the distance between the tip of the reinforcing bar protruding from the end face of one floor slab and the end face of the other floor slab is within the range of 15 mm to 45 mm. Floor slab joint structure described in the section.

Images