JP7316243B2 - Floor slab joining method, floor slab renewal method - Google Patents

Description

The present invention relates to a floor slab joining method and a floor slab renewal method using the same.

When updating the road slab of a road bridge, the road slab is divided into multiple areas in the road width direction (perpendicular to the bridge axis) for the purpose of ensuring the running of vehicles during construction, and each area In some cases, split construction is performed to replace precast floor slabs.

In the divisional construction, as the first step, after restricting the driving lane to a part of the road slab, the road slab in another area is removed and a new precast floor slab is installed at the removed location. After that, as a second step, after restricting the driving lane on the precast floor slab, the above partial area of the road floor slab is removed and a new precast floor slab is installed at the removed location (for example, patent document 1).

After the divided construction, the road slabs are constructed by arranging a plurality of precast slabs in the width direction of the road. Both precast floor slabs are joined by forming joints. Reinforcement joints protrude from both precast floor slabs in the filling portion, and stress is transmitted between the two precast floor slabs by forming lap joints at these reinforcement joints.

Patent No. 5700608

In the second process, the existing precast floor slabs installed in the first process are used as driving lanes, and concrete is filled between the precast floor slabs and the newly installed precast floor slabs to form a gap. do. At this time, the existing precast floor slabs used as the traffic lane vibrate vertically as the vehicle travels, and this vertical vibration may lead to a deterioration in the quality of the interstitial space.

For example, when the concrete in the filling section has hardened to some extent, the existing precast floor slab A1 vibrates vertically as indicated by the arrows in FIG. A mesh opening C may occur at the interface, and a shear crack D may occur in the concrete itself of the interfilling portion B as shown in FIG. 12(b).

Before the concrete in the interfilling portion B hardens, the existing precast floor slab A1 vibrates vertically as indicated by the arrow in FIG. The reinforcing bar joints E1 and E2 projecting from are displaced relative to the concrete. When such relative displacement of the reinforcing bar joints E1 and E2 with respect to the concrete occurs, the water in the concrete tends to gather in the vicinity of the reinforcing bar joints E1 and E2, and the cement particles become sparse in the vicinity of the reinforcing bar joints E1 and E2, causing the concrete to become sparse. adhesion to the reinforcing bar joints E1 and E2.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a floor slab joining method and the like capable of forming a high-quality filling portion.

A first invention for solving the above-mentioned problems is to install a precast floor slab on the side of an existing floor slab that is used as a driving lane, and to face the existing floor slab and the precast floor slab by a fixing mechanism. After the ends are fixed together, a hardening material is filled between the ends to form an interstitial portion, an auxiliary girder is installed on the lower surface of the end of the precast floor slab on the existing floor slab side, and the The floor slab joining method is characterized in that the fixing mechanism fixes the ends of the existing floor slab and the precast floor slab to the cross beams attached to the auxiliary girders.

In the present invention, the ends of the existing floor slab used as a driving lane and the newly installed precast floor slab are fixed to each other, and a hardening material such as concrete is filled in between them to form a filling portion. It is possible to reduce the vertical vibration of the existing floor slab at the end portion thereof when forming the filling portion, thereby suppressing the quality deterioration of the filling portion.

It is desirable to use ultra-high-strength fiber-reinforced concrete as the hardener.
As a result, the adhesion performance of the hardening material to the reinforcing bar joint can be improved, and shear cracking of the hardening material due to the vertical vibration of the existing floor slab is less likely to occur.

It is desirable that a reinforcing bar joint protrudes into the interstitial space from the existing floor slab and the precast floor slab, and that the reinforcing bar joint is deformed in the interposing space due to vertical vibration of the existing floor slab.
The vertical vibration of the existing floor slab deforms the reinforcing bar joints in the interstitial space, suppressing the relative displacement of the reinforcing bar joints with respect to the hardening material, and improving the adhesion of the hardening material to the reinforcing bar joints.

It is desirable that each of the facing ends of the existing floor slab and the precast floor slab has unevenness.
As a result, openings in the filling portion due to vertical vibration of the existing floor slab are less likely to occur.

In addition, in the present invention , when performing construction using the auxiliary girder for floor slab support, the fixing mechanism can be preferably formed using the auxiliary girder .

The second invention comprises a step (a) of using a part of the road slab in the road width direction as a driving lane and replacing another area with a new precast slab, and using the precast slab as a driving lane. and a step (b) of replacing the partial area with a new precast floor slab, wherein in the step (b), the precast floor slab used as a driving lane is used as the existing floor slab as the first A floor slab renewal method characterized by joining precast floor slabs together by the floor slab joining method of the invention.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a floor slab joining method and the like capable of forming a high-quality filling portion.

The figure which shows the outline of the floor slab update method. The figure which shows the outline of the floor slab update method. The figure which shows the reinforcement joint 211,311. The figure which shows the fixing mechanism 4. FIG. The figure explaining deformation|transformation of the reinforcement joints 211 and 311. FIG. The figure explaining deformation|transformation of the reinforcement joints 211 and 311. FIG. An example in which unevenness is provided at the ends of the precast floor slabs 21 and 31. FIG. An example in which the filling portion 5 and the precast floor slabs 21 and 31 are meshed in a crank shape. An example of a fixing mechanism in which steel plates 44 are provided between all support girders 102. FIG. The figure which shows the fixing mechanism 4a. FIG. 4 is a view showing fixing mechanisms 4b, 4b'; The figure explaining the influence of the vertical vibration of precast floor slab A1.

Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[First embodiment]
(1. Floor slab update method)
FIG. 1(a) is a diagram showing a highway bridge 1 to which a floor slab updating method according to an embodiment of the present invention is applied. In this embodiment, the road bridge 1 is constructed by supporting a road slab 101 made of concrete from below with support girders 102 .

The support girders 102 are arranged so as to extend in the direction of the bridge axis, and steel box girders are used in this embodiment. A plurality of support girders 102 (two in the example shown) are provided at intervals in the direction perpendicular to the bridge axis.

A plurality of driving lanes are provided on the road slab 101 in the direction perpendicular to the bridge axis, and balustrades 103 are provided at both ends of the upper surface of the road slab 101 in the direction perpendicular to the bridge axis.

Here, the direction of the bridge axis is the direction in which the vehicle travels, and corresponds to the direction normal to the plane of FIG. 1(a). The direction perpendicular to the bridge axis is a direction perpendicular to the direction of the bridge axis in a plane, and corresponds to the left-right direction in FIG. 1(a). In the following explanation, the direction perpendicular to the bridge axis may be referred to as the road width direction.

In addition, the road bridge 1 is not restricted to the above. For example, in the present embodiment, steel box girders are used as the support girders 102, but H-shaped steel, synthetic girders, etc. may be used as the support girders 102, and the support girders 102 adjacent in the road width direction may be They may also be connected by transverse beams (not shown).

In this embodiment, when updating the road slab 101 of the road bridge 1 shown in FIG. Split work will be carried out to replace the concrete precast floor slabs. The procedure of this floor slab renewal method will be described below. At the end of the procedure, the precast floor slabs are also joined together, and the joining method (floor slab joining method) will also be explained here.

When updating the road slab 101, first, as shown in FIG. Auxiliary girders 11 are provided to limit the driving lane to a partial region a of the road floor slab 101 (the right region in the example of the figure). Auxiliary girders 11 are provided so as to extend in the bridge axis direction between adjacent support girders 102 .

After that, in this embodiment, while the area a of the road slab 101 is used as a driving lane, another area b of the road slab 101 (the left area in the example of the figure) is removed.

The state after removal is shown in FIG. 1(c). In the example shown in the figure, the range where the road slab 101 is to be removed is set to the left side of the auxiliary girder 11 and road shoulder protection fence 104. supported by This is because the original road slab 101 was not designed on the assumption that the region b was removed. Vehicles can run over it.

After that, as shown in FIG. 1(d), a new precast floor slab 21 is placed at the location where the road floor slab 101 is removed. A balustrade 23 and a road shoulder protection fence 24 are installed on both ends of the upper surface of the precast floor slab 21 in the width direction of the road. The road shoulder protective fence 24 is arranged at the end on the side of the area a, and the balustrade 23 is arranged at the opposite end.

After replacing the area b of the road slab 101 with the new precast floor slab 21 in this manner, construction is performed to replace the area a of the road slab 101 with the new precast floor slab.

Here, the driving lane is limited to the precast floor slab 21, and the existing precast floor slab 21 (existing floor slab) is used as the driving lane, and the above-mentioned area of the road floor slab 101 is shown in FIG. Remove a.

After that, as shown in FIG. 2B, a new precast floor slab 31 is placed on the side of the existing precast floor slab 21 at the location where the road floor slab 101 is removed. The precast floor slab 21 side end of the precast floor slab 31 is supported from below by the auxiliary girder 11 , and a balustrade 32 is installed on the upper surface of the precast floor slab 31 at the opposite end.

After the precast floor slabs 31 are installed in this way, in this embodiment, as shown in FIG. The fixing mechanism 4 is installed on the lower surfaces of both precast floor slabs 21 and 31 . Details of the fixing mechanism 4 will be described later.

Then, a form (not shown) is installed, and concrete, which is a hardening material, is filled between the opposing ends of both precast floor slabs 21 and 31, and the hardened concrete fills the gaps 5 along the bridge axis direction. (longitudinal joint) is formed. In this embodiment, ultra high strength fiber reinforced concrete (UFC) containing reinforcing fibers such as steel fibers is used as the concrete.

FIG. 3 is a horizontal view of the filling portion 5 . In this embodiment, reinforcing bar joints 211 and 311 are embedded in the opposing ends of the precast floor slabs 21 and 31 , respectively, and a part of each reinforcing bar joint 211 and 311 protrudes into the filling section 5 .

The protruding portions of the respective reinforcing bar joints 211 and 311 are arranged in a comb shape with a gap in the bridge axis direction (corresponding to the vertical direction in the drawing). The protruding portions are arranged to mesh. A fixing body (not shown) widened with respect to the diameter of the reinforcing bar may be provided at the tip of the projecting portion of the reinforcing bar joints 211 and 311 .

The filling part 5 is formed by pouring concrete between the precast floor slabs 21 and 31 while using the precast floor slab 21 as a driving lane. As described above, the precast floor slab 21 vibrates up and down when the vehicle travels. Vertical vibration is reduced at the ends. Therefore, the opening of the filling portion 5 and the shear cracking of the concrete of the filling portion 5 described with reference to FIGS. In addition, the adhesion performance of concrete to the reinforcing bar joints 211 and 311 described with reference to FIG.

In addition, in this embodiment, ultra-high-strength fiber-reinforced concrete reinforced with reinforcing fibers is used as concrete, which also improves the adhesion performance of concrete to the reinforcing bar joints 211 and 311, It brings about effects such as suppression of shear cracks. However, it is also possible to use cementitious materials other than ultra-high-strength fiber-reinforced concrete as the hardener.

Through the above procedure, the area a of the road floor slab 101 is replaced with a new precast floor slab 31, and the precast floor slabs 21, 31 are joined. Thereafter, as shown in FIG. 2(d), the road shoulder protection fence 24 and the like are removed, and the renewal work of the road floor slab 101 is completed.

(2. Fixing mechanism 4)
FIG. 4(a) is a diagram showing the fixing mechanism 4. FIG. As described above, the fixing mechanism 4 fixes the opposing ends of the precast floor slabs 21 and 31, and has the distribution girders 41, the spacers 43, etc. in addition to the auxiliary girders 11. As shown in FIG.

The distribution crossbeams 41 are crossbeams extending in the road width direction (corresponding to the horizontal direction in the drawing), and are provided on both sides of the auxiliary girder 11 in the road width direction.

FIG. 4(b) is a cross section along line cc in FIG. 4(a). As shown in the figure, the distribution crossbeam 41 has a T-shaped cross section with a horizontal plate 412 at the upper end of a vertical plate 411 . The distribution horizontal girder 41 is used by attaching its vertical plate 411 to the mounting plate 111 of the auxiliary girder 11 with fasteners 112 such as bolts.

The spacers 43 are arranged between the horizontal plates 412 of the distribution cross beams 41 on both sides of the auxiliary girder 11 and the precast floor slabs 21, 31, respectively.

Holes 413 are formed in the horizontal plates 412 of the distribution beams 41, and the shafts of the headed bolts 42 are passed through the holes 413 of the distribution beams 41 on both sides of the auxiliary beam 11, and the ends thereof are attached to the precast floor slabs. The ends of the precast floor slabs 21 and 31 are fixed to the distribution girders 41 on both sides of the auxiliary girders 11 by screwing them into screw holes of inserts 212 and 312 embedded in the lower surfaces of 21 and 31, respectively.

In this embodiment, while the ends of both precast floor slabs 21 and 31 are fixed by the fixing mechanism 4, a formwork (not shown) is installed and concrete is placed between the ends. , the interfilling portion 5 is formed as shown in FIG. 2(c).

As described above, in this embodiment, when the precast floor slab 21 is used as a driving lane and the area a of the road floor slab 101 is replaced with the precast floor slab 31, the ends of the precast floor slabs 21 and 31 are fixed to each other. Then, concrete, which is a hardening material, is filled in the gap to form the filling portion 5 . As a result, the vertical vibration of the precast floor slab 21 during the formation of the interfilling portion 5 is reduced at the ends thereof, so that the opening of the interfilling portion 5 and the shear cracking of the concrete of the interfilling portion 5 are suppressed. It is possible to form a high-quality filling portion 5. In addition, since the relative displacement of the reinforcing bar joints 211 and 311 to the concrete is suppressed, the adhesion performance of the concrete to the reinforcing bar joints 211 and 311 does not deteriorate, which also contributes to the formation of the high-quality filling portion 5 .

In addition, by using ultra-high-strength fiber-reinforced concrete as the concrete of the filling part 5, the adhesion performance of the concrete to the reinforcing bar joints 211 and 311 can be improved, and the shear of the concrete accompanying the vertical vibration of the precast floor slab 21 can be improved. Cracks are less likely to occur. Moreover, the use of ultra-high-strength fiber-reinforced concrete has the advantage that the protruding portions of the reinforcing bar joints 211 and 311 can be shortened, and the width of the interfilling portion 5 can be reduced.

Further, in this embodiment, construction work is performed using the auxiliary girder 11 for supporting the floor slab, but the fixing mechanism 4 can be preferably formed by attaching the distribution horizontal girder 41 to the auxiliary girder 11 .

However, the present invention is not limited to the above embodiments. For example, in the present embodiment, the ends of both precast floor slabs 21 and 31 are fixed by the fixing mechanism 4 when the interfilling portion 5 is formed. direction), as shown in FIG. You may make it deform|transform. As a result, relative displacement of the reinforcing bar joints 211 and 311 with respect to the concrete is further suppressed, and adhesion performance of concrete to the reinforcing bar joints 211 and 311 is improved.

Further, as shown in FIG. 6A, which is a horizontal view of the filling portion 5, the rebars 51 in the bridge axis direction (corresponding to the vertical direction in the drawing) are placed across a plurality of rebar joints 211 and 311. The protruding portions of the reinforcing bar joints 211 and 311 may be connected by fixing the protruding portions of the reinforcing bar joints 211 and 311 to the reinforcing bars 51 using the binding tool 52 or the like. Here, a plurality of (two in the example in the figure) reinforcing bars 51 are arranged in parallel, and the protruding portions of the reinforcing bar joints 211 and 311 are fixed to the respective reinforcing bars 51. However, even if there is only one reinforcing bar 51, good.

In this case, when the precast floor slab 21 vibrates vertically, the concrete of the filling portion 5 is displaced by the vertical vibration of the precast floor slab 21 as shown in FIG. Therefore, in this case as well, the relative displacement of the reinforcing bar joints 211 and 311 with respect to the concrete is further suppressed, and the adhesion performance of the concrete to the reinforcing bar joints 211 and 311 is improved.

Further, in order to suppress the occurrence of openings (see FIG. 12(a)) of the interfilling portion 5, as shown in FIG. It is also effective to improve the adhesion of concrete. In the example of FIG. 7, the ends of the precast floor slabs 21 and 31 are provided with unevenness on the plane, but they may be provided with unevenness on the vertical surface. Further, in the example of FIG. 7, the reinforcing bar joints 211 and 311 protrude from the convex portions, but the reinforcing bar joints 211 and 311 may protrude from the concave portions. In addition, after the concrete in the filling section 5 has hardened, prestressing is introduced to the precast floor slabs 21 and 31 by PC steel material or the like that penetrates the filling section 5, and the precast floor slabs 21 and 31 are tightened to the filling section 5 side. This is also effective for suppressing eye opening.

Furthermore, as shown in FIG. 12(a), the interstitial portion 5 is open and the durability is lowered due to the intrusion of deterioration factors. By forming the precast floor slabs 21 and 31 into a crank-like (hook-like) meshing shape, when the opening C of the filling portion 5 occurs as shown in FIG. lengthen and improve durability. Furthermore, by using ultra-high-strength fiber-reinforced concrete as the concrete of the filling portion 5, damage can be concentrated on the opening C of the filling portion 5 without causing shear cracks in the concrete of the filling portion 5. , can control the entry route of degradation factors.

Furthermore, in the present embodiment, the fixing mechanism 4 is used to join the precast floor slabs 21 and 31 when the road slab 101 is renewed. It can also be used in a case where the road floor slab 101 is widened by installing a new precast floor slab on the side of the existing floor slab. In this case, the opposing ends of the road slab 101 and the precast slab are fixed by a fixing mechanism 4, and concrete is placed between the ends to form the filling portion 5. As shown in FIG.

The configuration of the fixing mechanism 4 is not limited to that described above. For example, when the auxiliary girder 11 for supporting the floor slab is not used, the opposite ends of the precast floor slabs 21 and 31 are fixed to both ends of the distribution horizontal girder 41 which is continuous in the width direction of the road. is also possible.

Further, as shown in FIG. 9(a), when the precast floor slabs 21 and 31 are supported by a plurality of support girders 102 spaced apart in the road width direction, the steel plate between all the support girders 102 44 may be installed as a fixing mechanism. The structure of the support girder 102 may be an H-shaped steel or a box girder as shown in FIG.

FIG. 9(b) shows four support girders 102 provided at regular intervals in the road width direction as shown in FIG. 9(a). The displacement of the precast floor slabs 21 and 31 is simulated when the steel plate 44 is provided between 102 and when the thickness of the steel plate 44 is 9 mm and a live load is applied on the precast floor slab 21 . , 31 is calculated. As shown in FIG. 9(b), by arranging the steel plates 44 between all the support girders 102, the deviation between the precast floor slabs 21 and 31 can be greatly reduced.

The thickness of the steel plates 44 and the number and pitch of the steel plates 44 arranged in the bridge axis direction are determined according to the assumed live load, the rigidity of the support girder 102, the span length, etc., and are not particularly limited. Further, instead of the steel plate 44, a plate material made of other materials such as fiber reinforced plastics (FRP) or ultra-high strength fiber reinforced concrete may be used.

Moreover, although the fixing mechanism 4 is formed on the lower surface of the precast floor slabs 21 and 31 in this embodiment, the fixing mechanism is not limited to that formed on the lower surface of the precast floor slabs 21 and 31 . For example, a fixing mechanism can be formed between opposite ends of the precast floor slabs 21, 31, and an example of such a fixing mechanism will be described below as a second embodiment. In the second embodiment, configurations different from those of the first embodiment will be mainly described, and descriptions of the same configurations will be omitted by attaching the same reference numerals in the drawings and the like.

[Second embodiment]
In the fixing mechanism 4a shown in FIG. 10(a), a steel plate 45 is embedded in each of the opposing ends of the precast floor slabs 21 and 31, and a part of each steel plate 45 is in the space S between the ends. Protruding. The steel plate 45 is a plate-like steel material, and is arranged with its plate surface oriented in the vertical direction.

FIG. 10(b) shows a cross section along line d--d in FIG. 10(a). As shown in the figure, the protruding portions of the respective steel plates 45 described above are stacked in the bridge axis direction (corresponding to the vertical direction in the figure). These protruding portions are arranged so that the positions of long holes 451 formed in the protruding portions overlap. , the projecting portions of both steel plates 45 are fastened. The long holes 451 are provided along the road width direction (corresponding to the left-right direction in the figure), and can absorb installation errors of the precast floor slabs 21 and 31 .

As a result, the opposing ends of the precast floor slabs 21 and 31 are connected to each other by the fixing mechanism 4a using the steel plate 45, and the ends are fixed to each other. The fixing mechanism 4a does not require the auxiliary girder 11 and the like when installed, and can be easily constructed even when the auxiliary girder 11 and the like are not provided. Furthermore, the fixing mechanism 4a can also serve as a joint for the precast floor slabs 21 and 31, and the reinforcing bar joints 211 and 311 can be omitted.

Various other fixing mechanisms are conceivable as the fixing mechanism provided between the opposing ends of the precast floor slabs 21 and 31 . A fixing mechanism 4b shown in FIG. 11(a) is an example of such a structure, in which both flanges of an I-shaped steel 48 are fixed to opposite ends of the precast floor slabs 21 and 31, respectively.

The I-shaped steel 48 is a steel material having T-shaped flanges on both ends of the web. installed to extend to One or more holes 481 are provided in the web. The hole 481 is for filling the filling portion 5 with concrete.

FIG. 11(b) shows a cross section along line ee in FIG. 11(a). As shown in the figure, both flanges of the I-shaped steel 48 are inserted into planar T-shaped slits provided at opposite ends of the precast floor slabs 21 and 31, respectively. Reference numeral 313 in the figure denotes a box-out member embedded in the ends of the precast floor slabs 21, 31 to form the slits. It is provided so that it may open respectively.

Also, inserts 314 are embedded in the opposite ends of the precast floor slabs 21 and 31 from the end faces to the upper side of the T-shaped slit. By screwing a bolt 49 into the threaded hole of the insert 314, the flange of the I-shaped steel 48 inserted into the slit can be pressed outward (in the direction away from the space S) by the tip of the bolt 49. Both flanges of the I-shaped steel 48 are fixed to the ends of the precast floor slabs 21 and 31, respectively.

In the above example, the opposing ends of the precast floor slabs 21 and 31 are connected to each other by the fixing mechanism 4b using the I-shaped steel 48, and the ends are fixed to each other. The I-shaped steel 48 can be inserted from above into the slit after the precast floor slab 31 is installed, and construction is simple.

In the above example, both flanges of the I-shaped steel 48 are pressed outward by the tip of the bolt 49, but as shown in the fixing mechanism 4b' in FIG. Only the plate 31 side flange) may be pressed outward with bolts 49 . At this time, the other flange (the flange on the precast floor slab 21 side in the example of the figure) is pressed against the wall surface of the slit and locked and fixed. In this case, the bolt 49 and the insert 314 can be omitted on the other flange side.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that those skilled in the art can conceive of various modifications or modifications, including the materials used, within the scope of the technical ideas disclosed in the present application, and of course the techniques of the present invention be understood to be within the scope of

1: Road bridges 4, 4a, 4b, 4b': Fixing mechanism 5: Filling part 11: Auxiliary girders 21, 31: Precast floor slabs 41: Distribution transverse girders 42, 46: Headed bolts 43: Spacers 44, 45: Steel plate 47: Nut 48: I-shaped steel 49: Bolt 51: Reinforcement bar 52: Binding tool 101: Road floor slab 102: Support girder 211, 311: Reinforcement joint

Claims (5)

A precast floor slab is installed on the side of an existing floor slab that is used as a driving lane, and after fixing the opposing ends of the existing floor slab and the precast floor slab with a fixing mechanism, a Filling the hardening material to form the filling part ,
An auxiliary girder is installed on the lower surface of the end of the precast floor slab on the existing floor slab side,
A floor slab joining method, wherein the fixing mechanism fixes the end portions of the existing floor slab and the precast floor slab to the horizontal beams attached to the auxiliary girders. 2. The floor slab joining method according to claim 1, wherein ultra-high-strength fiber-reinforced concrete is used as said hardening material. A reinforcing bar joint protrudes from the existing floor slab and the precast floor slab into the interstitial space,
3. The floor slab joining method according to claim 1, wherein said reinforcing bar joint is deformed in said filling portion by vertical vibration of said existing floor slab. 4. The floor slab joining method according to any one of claims 1 to 3, wherein opposing ends of said existing floor slab and said precast floor slab each have unevenness. A step (a) of using a partial area of the road slab in the road width direction as a driving lane and replacing another area with a new precast slab;
A step (b) of using the precast floor slab as a driving lane and replacing the partial area with a new precast floor slab;
has
In the step (b), the precast floor slabs used as a driving lane are used as the existing floor slabs, and the precast floor slabs are joined together by the floor slab joining method according to any one of claims 1 to 4 . A floor slab update method characterized by:

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