JP2017101529A - Pca FLOOR SLAB AND INSTALLATION METHOD THEREOF, AND Pca BEARING AND INSTALLATION METHOD THEREOF - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Pca floor slab, installable with every single span, carriable on the Pca floor slab just after installation, and satisfying integrating by being vertically-horizontally installed.SOLUTION: A first Pca floor slab comprises a first bending part being a truncated chevron shape in a cross section in the crossing direction and bending by a predetermined angle to both end parts from a horizontal part of a central part, a second bending part in which a root part of the truncated chevron shape forms a horizontal bottom surface by inversely bending by the predetermined angle and both end parts being a vertical end surface, and a second Pca floor slab installed between a bearing and any sidewall of both outsides is a shape of extending a horizontal part of a central part up to an end part as it is on an upper surface of one side with the one side only as the second bending part among a structure possessed by the first Pca floor slab, and the first and second Pca floor slabs comprise a longitudinal sectional line joint composed of a reinforcement provided on the upper side of an end surface for joining the mutual Pca floor slabs in the crossing direction and a crossing line joint composed of a reinforcement provided on the upper side of an undersurface of the Pca floor slab for joining the mutual Pca floor slabs in the longitudinal direction.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a Pca floor slab installed for each single diameter with respect to a plurality of rows of Pca bearings that are continuous in the axial direction (longitudinal direction) in a shield tunnel, a method for installing the same, a Pca bearing, and a method for installing the same.

Conventionally, in a road bridge on the ground, a Pca floor slab integrated in a transverse direction is installed in a plurality of rows of girders continuous in an axial direction (longitudinal direction). In this case, a loop joint is known as a technique for joining crossing lines. The loop joint is a method of filling the joint part concrete with the internal reinforcement arranged while the lower bars of both sides are butted and the double reinforcing bars exposed in a loop shape are crossed with each other.
Originally, the RC structure is desirably joined by a lap joint excellent in bending performance and fatigue durability performance. However, the lap joint has a longer fixing length than the loop joint, and therefore requires a formwork support for supporting the joint concrete. Therefore, loop joints that do not require this are simple and replace lap joints.

Since the loop joint arranges internal bars that penetrate the inside of the ellipse where the loops overlap each other, this part becomes a highly rigid elliptical girder, and both floor slab bars are fixed in a loop shape on the elliptical girder. . As a result, there is no concern about the fatigue durability performance, but the bending performance varies depending on the shape. For this reason, structural verification is usually performed not on a longitudinal section with a loop joint but on a transverse section without this.
The types of loop joints include those with no arcs, hooks with arcs missing, and straight rather than arcs with protrusions at the ends, straight with mechanical ends. However, in the description below, these are collectively referred to as “loop joints”.

JP 2008-303538 A JP 2000-282610 A JP 2006-200206 A JP 2008-75449 A

  Conventionally, when a Pca floor slab integrated in a transverse direction (width direction) is installed in a plurality of columns that are continuous in an axial direction (longitudinal direction) on a ground road bridge or the like, as shown in Patent Document 1 The transverse line joint is joined by the loop joint described above, and there is no longitudinal line joint. The reason why the structure is integrated in the transverse direction (width direction) regardless of the individual structure between the single diameters is that the installation work becomes efficient and the cost is reduced by reducing the stress. Further, the reason why the longitudinal line joint is not provided is that if a loop joint is arranged as a longitudinal line joint, its internal reinforcement becomes an obstacle to the internal reinforcement of the loop joint of the transverse line joint. As for the installation of the Pca floor slab, as shown in FIG. 30, the lower surface where both loop joints abut each other becomes an obstacle to the installed lower surface when attempting to install it from vertically above. Therefore, it is forced to install from the horizontal lateral direction from the non-installed side. Temporarily, in the structure which has a vertical line joint in addition to a transverse line joint, since it becomes impossible to install even if it installs from a horizontal direction, there is no vertical line joint even if a transverse line joint exists. Therefore, when installing a Pca floor slab that is long and integrated in the transverse direction (width direction), it is customary to use large cranes and suspension balances to disperse suspension points so that they are not damaged by their own weight during lifting. It was.

  On the other hand, conventionally, when installing Pca floor slabs in a plurality of rows of bearings continuous in the axial direction (longitudinal direction) in an underground shield tunnel, as shown in Patent Documents 1 and 3, the transverse direction (width direction) In general, a Pca floor slab integrated with a cross joint is joined by a loop joint. There is no longitudinal line joint, and the reason is the same as in the case of the above-mentioned road bridge.

However, in recent years, the scale of shield tunnels has increased, and it has become necessary to install the floor slab at the same time as excavation. As a result, in a structure integrated in the transverse direction (width direction), the crane becomes large and requires a lifting balance, so that the construction efficiency is reduced or impossible in a narrow pit. Therefore, there is the following problem where a structure for installing separately between single diameters is inevitably required.
The following issues are inevitable because they are not integrated in the cross direction.
・ No cost reduction due to stress reduction.
・ Anchor bars are arranged at both ends of each floor slab to suppress vibration and prevent fatigue failure. This also increases the bearing width and increases costs.
-The entire structure becomes unstable and the durability is reduced.

In the case of the above “a”, as the joint structure of the longitudinal line, it is only necessary to find one that can be integrated in the transverse direction (width direction) while individually installing between single diameters. However, when the loop joint shown in Patent Document 1 is simply applied, as described above, the internal bars of the loop joint of the longitudinal line and the transverse line interfere with each other and cannot be established. Further, even during installation, the lower surface and the end surface to which the longitudinal line is to be abutted in addition to the transverse line interfere with each other and cannot be established. In short, a joint structure of a longitudinal line that satisfies the conditions has not been found.
C. The loop joint shown in Patent Document 1 does not assume installation on a bearing. If it is installed on the bearing, the joint will be damaged by its own weight or by the temporary load. Further, in the case of simultaneous excavation construction, it is necessary to transport the Pca floor slab on the Pca floor slab immediately after installation because of the segment transportation below the floor slab, and this cannot be solved.

Next, the half precast slab shown in Patent Document 2 is a technique for integrating in the transverse direction by arranging the upper reinforcing bars of the double rebar regardless of the joint. Therefore, this half precast slab is installed in contact with the upper surface of the bearing, and the concrete is placed after placing the upper bars. Then, as a result, the continuous lower muscle is interrupted and the slab thickness is lost, but it is possible to achieve integration in the transverse direction (width direction) although it is only the upper muscle. However, this technique also has the following problems.
D) Negative bending is dominant on the bearing, and tensile stress is generated mainly in the upper muscle, while the stress generated in the lower muscle is slight. However, the continuation of the lower bars here and the loss of the slab thickness also cause a problem such as fatigue failure in which cracks are generated on the upper surface of the slab due to vibration and stress concentration caused by dynamic load, and this grows.
The technique described in Patent Document 2 is a construction method in which upper bars are placed on the upper layer and concrete is placed. Therefore, like the technique described in Patent Document 1, the Pca floor slab is immediately after installation. It cannot be transported on the Pca floor slab and cannot withstand the load at the time of temporary installation.
In addition to integrating only the upper half of the slab thickness, the abutment surface is a straight line in the axial direction, so a fracture surface is likely to occur in the axial direction of the abutment location due to axial deformation. The fatigue resistance of the part is also low.

Furthermore, conventionally, when installing a Pca floor slab in a shield tunnel, as shown in Patent Document 3, the support between floor slab side walls is installed as a wall structure of a continuous precast member. There is.
When the support is a continuous wall structure, the concrete volume increases and the cost increases significantly. If it is an original strut / girder structure, it can be reduced, but the shape of the precast member that can be installed in the mine and its installation method have not been found.
In the case of the support structure by Pca, the support level is not uniform because of the influence of the unevenness and distortion of the segment itself. Therefore, there is a fear of damage due to stress concentration on the Pca floor slab.

For this reason, the level adjustment plate was arranged on the support for installing the Pca floor slab, and the Pca floor slab was installed by this amount, and then the non-shrink mortar was filled. However, the construction cost increases and the construction period is delayed.
Ko Patent Document 4 shows a girder constructed by laying a Pca beam on a Pca pillar. This girder lacks the struts, and after installation, the missing part requires a formwork. In addition, the installed state becomes unstable and the risk of falling off cannot be excluded.

  As described above, at present, a Pca floor slab structure that can be transported on a Pca floor slab immediately after being installed and installed on a single diameter and that is integrated vertically and horizontally has not been found. Similarly, at present, a structure of Pca bearings between floor slab side walls that satisfies the fact that the concrete volume is small, the installation is simple, the bearing levels are uniform, and the Pca floor slabs are not adversely affected has not been found.

  In order to solve the above-mentioned problems, the present invention is a Pca floor slab installed at every single diameter between at least one row of supports that are continuous in the longitudinal direction and both outer side walls. , A first Pca floor slab installed between a plurality of rows of bearings and a second Pca floor slab installed between the bearing and one of the outer side walls. The cross-section is C-shaped, the first bent part that bends by a predetermined angle from the horizontal part of the central part to both ends, and the base part of the C-shaped part bends reversely by the predetermined angle to form a horizontal bottom surface The second Pca floor slab has a structure in which the first Pca floor slab has only one second bent portion, and the second Pca floor slab has a second bent portion. The upper surface on one side has a structure in which the horizontal portion at the center extends to the end as it is, and the first and second The ca floor slab includes a longitudinal line joint made of a reinforcing bar provided on the upper side of the end face in order to join the Pca floor slabs in the transverse direction, and the Pca floor slab in order to join the Pca floor slabs in the longitudinal direction. And a transverse line joint made of reinforcing bars provided on the upper side of the lower surface of the steel sheet.

The Pca floor slab according to the present invention can provide the following effects.
a In the transverse direction (width direction), the end faces of the Pca floor slabs and the end faces of the Pca floor slabs and the facings on the side walls are in close contact with each other. It is possible to minimize deformation and stress generated in the reinforcing bar. As a result, even if the joint is not connected, the Pca floor slab can be transported by the carriage on the Pca floor slab just after installation. In the case of simultaneous excavation construction, the space below the floor slab can be opened for segment transportation.
b In the part from the second bent part of the Pca floor slab to the end surface, double reinforcing bars that are fixed to the double reinforcing bars in the horizontal part of the central part are also placed, so that the joint is not connected and the load at the time of temporary loading is loaded. Does not damage the Pca slab.

c In the joint structure of Pca floor slabs, lap joints that are inexpensive and easy to construct are adopted as longitudinal line joints, and even if the transverse line joint is a general loop joint, the internal reinforcement of the transverse line joint is the arrangement of the longitudinal line joint. Since there is no obstacle with the muscle, the joint structure can be established vertically and horizontally. Furthermore, if both ends of the lap joint are hook-shaped, the lap size can be shortened, and the specifications of the joint can be reduced.
d Integrate the rebars in both Pca slabs in the transverse direction (width direction) (for example, in prestressed Pca slabs used when the span is long, pre-stressed PC steel If the connecting rebars are embedded so as to wrap, the PC rebar connecting rebars in the floor slab are integrated with a lap joint in the transverse direction (width direction). As a result, it is possible to obtain a completed multi-diameter continuous structure, reducing the generated moment, reducing the thickness compared to the single-diameter structure, and reducing the cost.

e Because Pca floor slabs can be integrated into the transverse direction (width direction) even if they are installed for each single diameter,
・ Even if the scale of the shield tunnel is large, the installed crane will not be enlarged and the lifting balance will be unnecessary, so that construction efficiency can be secured.
-The combination of Pca floor slabs may mesh with the concavo-convex shape in the vicinity of the center of the end surface, and the corners of the end surface may mesh with the shape of the protruding portion (hereinafter referred to as “convex convex shape”). . In the case of the uneven shape, since it is engaged once and then moved horizontally as a whole, the installation work is troublesome, but after installation, a strong unity in the transverse direction can be obtained. In the case of a convex-convex shape, after installation, there is no strong unity compared to the former, but it is not necessary to move as a whole after meshing, so for example, while moving from the center individually in the horizontal horizontal direction It can be installed and is very convenient.
-As described above, the planar shape of the Pca floor slab is formed into an uneven shape or a convex-convex shape, and this shape is meshed and installed on the support. Moreover, it is set as the structure which opens a hole in this convex part, provides an anchor bar here, and is integrated in a cross direction (width direction). As a result, in order to suppress vibration and prevent fatigue failure, the anchor bars placed at the required locations on both ends of each floor slab will be reduced from 2 per bearing to one placed in the hole in the convex portion, compared to the case where they are not integrated. it can. In addition, since the bearing allowance on the bearing required for meshing on the bearing is reduced, the bearing width is reduced and the cost is reduced.

f In addition, according to the present invention, as shown in Patent Document 2, even in a half precast slab that includes only the lower bar in the Pca floor slab and the upper bar is continuous by lap connection of the assembled lap joint after installation, The flat end portion of the Pca floor slab is formed into a concavo-convex shape or a convex-convex shape, and is installed by meshing on a support. According to this, in general, even if a tensile stress is generated in the upper muscle on the bearing, the stress generated in the lower muscle is slight. Therefore, problems such as lack of structural rationality of the completed system due to incomplete continuation due to the discontinuation of the lower muscle, lack of proof stress during erection, and fatigue failure can be applied if the design allows. That is, in the half precast slab according to the present invention, strong integrity is obtained, and the fracture surface is less likely to be generated in the axial direction of the abutting portion with respect to the axial deformation, and durability can be increased. In addition, one row of anchor holes is provided in the convex portions to be meshed, and one row of anchor bars is installed. The upper bars can be integrated by lap connection of lap joints by filling with mortar. Since securing is unnecessary, the bearing width is reduced and the cost can be reduced. Further, the half precast floor slab according to the present invention has a structure in which the upper half of the floor slab thickness only on the bearing is lost (FIG. 9), but the structure in which the upper half of the floor slab thickness is lost over the entire floor slab (FIG. 10). However, the cross-sectional shape in the transverse direction may be a flat shape. That is, the structure including the shape can be simplified and the cost can be reduced. In addition, in the case of an upper muscle defect only on the bearing, if both ends of the lap joint are hook-shaped, the overlap dimension can be shortened and the defect can be slimmed. The applicable range is not limited to the inside of the tunnel, but supports a plurality of horizontally long Pca floor slabs that are installed perpendicularly to the bridge axis while being fixed with a plurality of girders parallel to the bridge axis. Because it can be adapted to the case, it is convenient.

In addition, the following effects can be achieved by the support structure between the side walls according to the present invention.
g Since the support structure is composed of struts and girders, the concrete volume can be reduced and the cost can be reduced compared to the conventional general continuous wall structure.
h Since the bearings are Pca girders that are longitudinal in the axial direction (longitudinal direction), there is little unevenness, and there is less concern about breakage due to stress concentration on the Pca floor slab.
i Even if a non-shrink mortar is required after installing the Pca slab, the amount used can be reduced, and the construction cost and construction period can be reduced.

j When the Pca girder is temporarily installed, as an arch action effect that the cross-sectional shape of the letter C exhibits, the load can be transmitted as a compressive force to the bottom surface and the end surface. Because it contains and sticks to the protruding muscles of the top of the column,
-Even if the joint part is not yet constructed, it becomes a continuous arch where both sides in the axial direction (longitudinal direction) are constrained, minimizing the deformation of the Pca girder and the stress generated in the reinforcing bar.
-Since the upper and lower double reinforcing bars are also arranged in the part from the bent part of the Pca girder to the end face and fixed to the upper and lower double reinforcing bars in the horizontal part of the center part, the joint part is not installed and the load at the time of erection is Even when loaded, the Pca girder will not be damaged.
-The Pca girder just after installation is stable and there is no fear of falling off the top surface of the column.
-Formwork is not required when placing concrete in the connection area, so there is no problem in logistics associated with excavation.

The entire k Pca girder member has a compressive stress due to the arch action effect exhibited by the cross-sectional shape of the letter C, so it can withstand the load during temporary installation even if the bent part is reduced in thickness relative to the center part. . Therefore, the space of the joint part of the Pca girder can be made large, and a lap joint that is inexpensive and easy to construct can be adopted.
In the lower rebar of l Pca girder, if the pre-tension bar is arranged as required, the span can be skipped, and the construction is rationalized and the cost is reduced.

FIG. 1 is a diagram showing a structure of a first Pca floor slab according to the present invention. FIG. 2 is a diagram showing the structure of the second Pca floor slab according to the present invention. FIG. 3 is a diagram showing the structural streaks of the first Pca floor slab. FIG. 4 is a diagram illustrating the structural streaks of the second Pca floor slab. FIG. 5 is a view showing three views including the joint structure of the first Pca floor slab. FIG. 6 is a view showing three views including the joint structure of the second Pca floor slab. FIG. 7 is a diagram illustrating a state in which both of the first and second Pca floor slabs are installed when the end faces are uneven. FIG. 8 is a diagram showing a state in which both the corners of the end faces of the first and second Pca floor slabs are convex and convex and are installed. FIG. 9 is a diagram (three-sided view) showing a structure of a half precast floor slab in which the upper half of the floor slab thickness is missing only in the flat upper portion of the center support without a bent portion and in the state of installation. FIG. 10 is a diagram (a front view and a plan view) showing a structure of a half precast slab that is flat without a bent portion and in which the upper half of the slab thickness is lost over the entire area of the slab, and a state at the time of installation. FIG. 11: is a figure which shows the crossing direction (width direction) cross section and the axial direction (longitudinal direction) cross section with the Pca floor slab for the Pca support according to the present invention. FIG. 12 is a view showing a Pca floor slab arranged in a transverse (width) direction and an axial (longitudinal) direction on a Pca bearing. FIG. 13 is a diagram showing the structure of the Pca digit. FIG. 14 is a diagram showing a joint state of the Pca strut and the Pca strut and the Pca girders. FIG. 15 is a diagram showing a process of tunnel excavation, segment lining and sleeper installation as Step 1. FIG. 16 is a diagram showing a process of placing invert concrete as step 2. FIG. 17 is a diagram showing a step of constructing a floor slab side wall and installing a Pca support as Step 3. FIG. 18 is a diagram showing a step of installing a Pca girder for each section as step 4. FIG. 19 is a diagram showing a step of placing the interstitial concrete in the opening portion of the Pca girder for each section as step 5. FIG. 20 is a diagram illustrating a step of performing joint bar arrangement on the Pca beam as step 6. FIG. 21 is a diagram showing a step of placing concrete in the U-shaped groove of the Pca digit for each section as step 7. FIG. 22 is a diagram showing a step of installing a Pca floor slab every three spans as step 8. FIG. 23 is a diagram showing a step of setting a second Pca floor slab for every three spans and placing interstitial concrete as Step 9. FIG. 24 is a diagram illustrating a process of transporting a Pca floor slab as Step 10. FIG. 25 is a diagram showing a step of arranging the joints in the longitudinal line and the transverse line of the Pca floor slab for each section as Step 11. FIG. 26 is a diagram showing a step of placing concrete in the joint portion of the Pca floor slab for each section as step 12. FIG. 27 is a diagram showing a completed image as step 13. FIG. 28 is a diagram showing anchor bar insertion and mortar fixing in the anchor bar hole in Step 8. FIG. 29 is a diagram illustrating concrete placement in the joint portion of the Pca floor slab in Step 12. FIG. 30 is a diagram illustrating a part of the process of installing the Pca floor slab.

  A preferred embodiment according to the present invention will be described below as an example with reference to the drawings. Example 1 is a suitable example of the structure of the Pca floor slab and the structure of the Pca support according to the present invention. Example 2 is a specific example relating to an installation process (installation procedure) of a Pca floor slab and a Pca support that is performed in parallel with the excavation of a shield tunnel.

First, the structure, installation and transportation of the Pca floor slab according to the present invention will be described, and then the structure and installation of the Pca support will be described.
1 and 2 are views showing the structure of a Pca slab according to the present invention in a cross-section (width direction) cross section. The first Pca floor slab 1 shown in FIG. 1 is installed on the Pca support upper surface at both ends. The second Pca floor slab 2 shown in FIG. 2 has one end on the Pca support upper surface and the other end on the side wall upper surface.

  As shown in FIG. 1, the structure of the first Pca floor slab 1 has a cross-section in the transverse direction (width direction) and a bent portion that is bent by a predetermined angle from the horizontal portion of the central portion to both end portions. A is provided, and the base of the C-shape is bent reversely by the same predetermined angle to provide a bent portion B that forms a horizontal bottom surface, and a vertical end surface is provided at the end thereof.

  As shown in FIG. 2, the second Pca floor slab 2 is provided with bent portions A and B on one side from the horizontal portion of the central portion, like the first Pca floor slab, and at the end thereof. Is provided with a vertical end surface, only the bent portion B is provided on the other side from the horizontal portion of the central portion, and the upper surface thereof has a shape in which the horizontal portion extends as it is to the end portion, and a vertical end surface is provided on the end portion. .

  As described above, the Pca floor slab according to the present invention can be transmitted as a compression force to the bottom surface and the end surface as an arch action effect by providing two bends (bending portions A and B), and the entire member is compressed. Stress is outstanding. For this reason, the deformation of the Pca floor slab and the stress generated in the reinforcing bar are minimized, and even when the bent portion is reduced in thickness with respect to the central portion, it can withstand a temporary load such as transportation of the Pca floor slab.

Next, the structural reinforcement provided in the Pca floor slab according to the present invention will be described.
FIG. 3 is a diagram showing the structural streaks of the first Pca floor slab 1, and FIG. 4 is a diagram showing the structural streaks of the second Pca floor slab 2.
In the temporary stage before filling the joint part concrete, as shown as “double rebar (temporary)” in the figure, from the horizontal part of the central part of the first Pca floor slab 1 and the second Pca floor slab 2, Arrange the double rebars to trace the letter C toward the end face to ensure the arch action behavior.

In addition, as shown in the figure as “double rebar (completed)”, in the completion stage after filling the joint part concrete, from the horizontal part of the central part of the first Pca floor slab 1 and the second Pca floor slab 2 The double reinforcing bars are projected horizontally from the bent portion A, and the reinforcing bars are arranged integrally in the transverse direction (width direction) via the joint portion to ensure the behavior of multiple transverse directions (width direction).
Therefore, in the Pca floor slab according to the present invention, the lower muscle of the bent part is wrapped as a lap joint on the lower part of the central part, and the upper part of the bent part is wrapped as a lap joint on the upper part of the central part.

Next, the joint structure applied to the Pca floor slab according to the present invention will be described.
FIG. 5 is a three-plane view (with the axial direction being the front) for showing the joint structure of the first Pca floor slab 1 and FIG. 6 is the joint structure of the second Pca floor slab 2. FIG. 12 shows a plan view and a side view in which Pca floor slabs are installed (deployed) on the Pca support in the transverse direction (width direction) and the axial direction (longitudinal direction). As shown in FIGS. 5, 6 and 12, the transverse (widthwise) line joint is a “crossing line joint”, and the axial (longitudinal) line joint is a “longitudinal line joint”.

The longitudinal line joint is a joint (lap joint or the like) that abuts the end face of the transverse direction (width direction) Pca floor slab and fills the joint part concrete. Here, the joint may be any of a loop joint, a joint having a projection such as a plate at the end, a joint having a hook at the end, a lap joint, and a mechanical joint. However, since the structure at the completion stage is secured in the transverse direction (width direction), the joint is required to have bending performance equivalent to that of the lap joint. Therefore, lap joints or mechanical joints are preferred over loop joints.
In the present invention, as described above, the space of the joint portion can be increased by two bends (bending portions A and B), so that a relatively wide space is necessary, but an inexpensive lap joint is used. In the temporary stage, the end face of the first Pca floor slab, the end face of the second Pca floor slab, and the second Pca floor are provided in the transverse direction (width direction) in order to ensure the transferability of the arch action. The end face of the plate and the facing side of the side wall are kept in close contact.

The transverse line joint is a joint (loop joint or the like) that fills the joint concrete by abutting the lower surface and the lower surface of the Pca floor slab in the axial direction (longitudinal direction). Here, the joint may be any of a lap joint, a loop joint, a joint having a projection such as a plate at the end, and a joint having a hook at the end. Moreover, it may be linear and the end may be mechanical, or it may be of fixed type.
However, lap joints are not suitable for adoption because the joint space cannot be widened, and the structure at the completion stage is secured in the transverse direction (width direction), so even if there is no bending performance equivalent to lap joints, Fatigue durability is sufficient.
Therefore, in the present invention, a versatile loop joint is used. In addition, if the lower surface and the lower surface of the Pca floor slab (shown in the side views shown in FIGS. 5 and 6) are not in close contact with each other in the axial direction (longitudinal direction), the joint concrete should not leak. Good.

Next, the planar shape of the Pca floor slab according to the present invention will be described. FIG. 7 is a diagram showing a state when both the first and second Pca floor slabs are installed.
Since the Pca floor slabs are arranged vertically and horizontally, if each Pca floor slab is installed with an error, there is a possibility that the end face and the end face of the Pca floor slab are not in close contact with each other in the transverse direction (width direction). For this reason, as shown in the plan views of FIGS. 5 and 6, the planar shape of each Pca floor slab is rectangular in plan view, but the corners of the four corners are not acute angles, and the corners are set using face wood or the like. Shall be dropped. By doing so, it is possible to ensure the close contact between the end face and the end face of the Pca floor slab while absorbing the installation error by the face wood.

In addition, while fixing the Pca floor slab with an anchor bar, in order to minimize the width of the support on which the Pca floor slab is installed, an uneven shape is provided on the planar shape of the Pca floor slab. That is, as shown in FIG. 5, the convex portions are provided on both sides in the transverse direction (width direction) of the first Pca floor slab 1. Moreover, as shown in FIG. 6, a recessed part is provided only inside the cross direction (width direction) of the 2nd Pca floor slab 2 (side facing the 1st Pca floor slab). On the support, as shown in FIG. 7 (a), the concavo-convex shape is meshed and a Pca floor slab is installed.
For the second Pca floor slab 2, in order to cope with the case where two second Pca floor slabs 2 are installed in the transverse direction (width direction) with respect to one row of Pca support, FIG. As shown in (b), you may prepare two 2nd Pca floor slabs 2 which provided the convex part.
Furthermore, the 1st Pca floor slab 1 has an anchor bar hole in the convex part of a transverse direction (width direction) both sides (FIG. 5). Further, the second Pca floor slab 2 has an anchor bar hole in the vicinity of the floor slab side wall (FIG. 6). By providing an anchor bar in the anchor bar hole, it is possible to suppress vibrations and thereby prevent fatigue failure.

Next, the installation process of the Pca floor slab will be described in the case where the vicinity of the center portion of the end surface is uneven. The Pca floor slabs are installed on two floors of Pca supports that are continuous in the axial direction (longitudinal direction) between the floor slab side walls, and the Pca floor slabs are joined together by providing joints on the Pca supports. Use a continuous digit structure. At that time, a rubber plate is interposed on the bearing to relieve stress concentration, ensure mobility and continuity, and prevent fatigue failure due to vibration (see FIG. 11).
Regarding the installation of the Pca floor slab 1 or 2 in the transverse direction (width direction), the bottom surface of each Pca floor slab 1 or 2 and the unevenness of the end face and the end face of the Pca floor slab 1 or 2 on the support top surface. Install it in close contact with each other. When the Pca floor slab is erected by the engagement of the concave and convex shapes, the allowance for the bottom of the Pca slab on the support increases, so that it can be erected stably and efficiently. That is, as shown in FIG. 7 (a), the first and second floor slabs are once meshed and then moved horizontally as a whole (FIG. 7 (a) bottom diagram). ), Installation work is troublesome, but after installation, a strong unity in the transverse direction can be obtained.

Furthermore, the installation process in the case where the corners of the end faces of the first and second Pca floor slabs are respectively convex and convex (that is, the respective corners opposite to each other are convex) will be described.
FIG. 8 is a diagram showing a state in which both the corners of the end faces of the first and second Pca floor slabs are convex and convex and are installed. As shown in the figure, both the first Pca floor slab and the second Pca floor slab can be installed by being engaged with each other while being individually moved from the horizontal lateral direction. In the case of convex-convex shape, after installation, there is no strong unity compared to the case of the previous concave-convex shape, but it does not need to move as a whole after meshing, so it has the advantage of excellent installation convenience .

  In the case of the convex and convex shape, the anchor bar hole in the vicinity of the floor slab side wall is provided in the second Pca floor slab, as in the case of the previous concave and convex shape, as shown in FIG. Here, an anchor bar hole may be provided in either the first Pca floor slab or the second Pca floor slab near the portion where the first and second Pca floor slabs are joined. For example, an anchor bar hole may be provided on the Pca floor slab side of the longer axial direction (longitudinal direction) length of the convex portion provided at the corners of the end faces of the first and second Pca floor slabs ( In FIG. 8, it is provided on the second Pca floor slab side).

In addition, on the upper surfaces of both outer side walls in the transverse direction (width direction), the end face of the Pca floor slab 2 and the opposite side of the side walls are brought into close contact with each other via camber or both outer concretes.
As for the anchor bar, as shown in FIG. 28, the mortar is fixed to the hole on the bearing side, and the anchor bar hole on the Pca floor slab and the joint concrete joint on the upper part are fitted with a vinyl chloride cap so as to enclose the joint. Place concrete to block adhesion.

Next, an example in which a half precast slab having a simpler structure is used in place of the Pca slab will be described.
FIG. 9 is a diagram (three-sided view) showing a structure of a half precast floor slab in which the upper half of the floor slab thickness is missing only in the flat upper portion of the center support without a bent portion and in the state of installation.
FIG. 10 is a diagram (a front view and a plan view) showing a structure of a half precast slab that is flat without a bent portion and in which the upper half of the slab thickness is lost over the entire area of the slab, and a state at the time of installation.
Unlike the first Pca floor slabs 1 and 2 described above, the half precast slab according to the present invention has a flat shape without using a bent portion. Therefore, the structure becomes simple. Moreover, structurally, as shown in FIG. 9, the upper half of the floor slab thickness is lost only at the center support or, as shown in FIG. A missing type can be employed.

Moreover, the planar shape of the edge part which joins half precast floor slabs is made into an uneven | corrugated shape or a convex-convex shape, and half precast floor slabs are joined and installed by meshing the said shape on a support. For both outsides, on the support or on the side wall in the tunnel, install the outer ends of the half precast slab (the left end of the left half precast slab in FIGS. 9 and 10). . And a half precast floor slab is equipped with the longitudinal line joint of a reinforcing bar in the upper part side of the end surface joined in a transverse direction, and the transverse line joint of a reinforcing bar in the upper part side of the undersurface joined in a longitudinal direction.
Furthermore, an anchor bar hole is provided on the outer end of the half precast slab or the convex portion that meshes the half precast slabs. Then, an anchor bar is installed in the anchor bar hole and filled with mortar. Moreover, about the convex part which meshes half precast slabs, an upper line is integrated by the lap connection.

Subsequently, transportation of the Pca floor slab will be described.
With the installation of the Pca floor slab in the shield tunnel, regarding the transportation of the Pca floor slab, in the case of simultaneous construction, it is necessary to transport the lower part of the floor slab on the installed Pca floor slab for convenience of segment transportation. There is. In addition, even in the case of construction after excavation, the width of the floor slab is often less than 2.5m, which is the maximum due to truck transportation restrictions, so that the space below the three divided floor slabs is narrow. Therefore, it becomes difficult to transport the Pca floor slab.

Then, the Pca floor slab in which the joint part concrete just installed is not yet constructed needs to bear the predetermined section, the transport load of the Pca floor slab and the work load of the joint part concrete placement. Since the former is usually larger, special measures are required for this.
Therefore, for transporting the Pca floor slab, two rows of rails are laid on the outermost edge of the central portion, and the carriage is transported using this. If it does so, the bending moment of a center part will be reduced and it is favorable. Moreover, although the rail is fixed by a rail clip, an insert for that may be installed in advance on the Pc floor slab.
In addition, the construction section length of joint part concrete will be determined from the workability by the single placement range of joint part concrete.

Next, the structure and installation of the Pca support according to the present invention will be described. FIG. 11: is a figure which shows the crossing direction (width direction) cross section and the axial direction (longitudinal direction) cross section with the Pca floor slab for the Pca support according to the present invention.
The Pca support has a Pca strut and girder structure. A Pca girder 3 is installed on the upper part of the Pca strut 4 standing on the invert, and the top surface of the Pca girder 3 is a support, and the Pca floor slab 1 or 2 is installed here. It is a structure to do.

The Pca girders 3 have a continuous structure in which the Pca girders are joined to each other by providing a joint at the upper part of the Pca strut 4. The Pca column 4 is joined to the Pca beam 3 below the joint.
FIG. 13 is a front view and a plan view showing the structure of the Pca girders 3 according to the present invention with the transverse direction (width direction) as the front. FIG. 14 is a view of the Pca support column 4 according to the present invention and the joined state of the Pca support column 4 and the Pca beam 3 viewed in the axial direction (longitudinal direction).

  As shown in the upper diagram of FIG. 13, the portion around the central portion of the Pca beam 3 is rectangular (not shown in the figure) or U-shaped groove (i in the figure) in the transverse (width direction) cross section. And at least the part that reaches the end (the part that is bent and forms the horizontal bottom surface as shown in the middle figure) has a U-shaped groove shape with the release surface facing upward in the transverse (width direction) cross section (in the figure) Ii). Moreover, the opening which penetrates perpendicularly | vertically in the cross direction (width direction) cross section is provided in the extreme end part and the extreme end part vicinity, and, thereby, the reinforcing bar which protrudes from the Pca support | pillar 4 (the protruding reinforcement shown in the left figure of FIG. 14) is provided. Concrete is cast and integrated here, including it (iii in the figure).

  As shown in the middle diagram of FIG. 13, the structure of the Pca girders 3 has a C shape when viewed from the longitudinal section, and is provided with a bent portion a that bends by a predetermined angle from the horizontal portion at the center to both ends. A bent portion “b” that is bent backward by a predetermined angle to form a horizontal bottom surface is provided at the base portion of the C shape. And the vertical end surface is provided in the both ends. The vertical end faces are the same in the two rows of side walls formed so as to sandwich the vertically penetrating openings, as shown in the lower plan view of FIG.

  Further, the arrangement of the Pca girders 3 in the joint joint of the upper part of the Pca support 4 is such that the horizontal part of the center part has upper and lower double reinforcing bars, and the upper and lower double reinforcing bars protrude horizontally from the bent part a to both sides, Join the same rebar of the adjacent Pca girder 3 (at the lap joint). Further, from the bent part a to the end part through the bent part b, the (double) reinforcing bar fixed by the lap joint to the central (double) reinforcing bar is arranged along the bending.

  The joints of the Pca girders 3 are joined directly (at the lap joint) immediately above the end faces facing each other. In this way, the Pca girders 3 are integrated in the axial direction (longitudinal direction). Moreover, the Pca support | pillar 4 makes a reinforcing bar protrude upwards in the downward direction of this joint (protruding bar shown in the left figure of FIG. 14), and joins to this. And Pca girders 3 and the Pca support | pillar 4 are joined by placing joint part concrete in the opening penetrated perpendicularly formed here (right figure of Drawing 14).

Regarding the installation of the Pca girders 3, the bottom surfaces of the individual Pca girders 3 are placed on the Pca struts 4 so that the end surfaces of the Pca girders face each other and are simply brought into close contact with each other, or are intimately contacted via camber or interstitial concrete. Depending on whether you want to install.
Further, in order to smooth the two rows of Pca bearings on which the Pca floor slabs 1 or 2 are installed, the upper surface of the Pca girders 3 exposes the reinforcing bars, and this upper surface is adjusted in level to the axial direction (longitudinal direction). A method of finishing with concrete continuously or a method of rubbing the joint concrete after adjusting the level when the Pca girders 3 are installed without exposing the reinforcing bars is used. Then, without arranging the level adjustment plate, the Pca floor slab 1 or 2 is directly placed with the rubber plate interposed therebetween (see FIG. 9).

  Next, as Example 2, the installation process (installation procedure) of the Pca floor slab and the Pca support will be described in steps 1 to 13. The installation process (installation procedure) according to the second embodiment is performed in parallel with the excavation of the shield tunnel, and the Pca floor slab is configured to mesh the uneven shape near the center of the end surface. FIGS. 15 to 27 for explaining Step 1 to Step 13 are cross-sectional views (width direction) of the shield tunnel. In addition, the right figure of each of FIGS. 19-21 is the figure which looked at the Pca support | pillar and the Pca girder from the cross section of the axial direction (longitudinal direction).

<Step 1> Shield digging, segment lining and sleeper installation FIG. 15 is a diagram showing steps of shield digging for tunnel, segment lining and sleeper installation as Step 1.
The rectangular shield tunnel is excavated with a flat rectangular shield machine (not shown). While excavating, the flat rectangular segments are assembled and lined behind the shield machine. After this lining, a single sleeper (one sleeper) is installed in the transverse direction (width direction) at a position where it is not buried in the invert concrete and does not obstruct the Pca strut behind the shield machine. Since the shield tunnel has a flat rectangular shape, the integrated sleeper is horizontally long in the transverse direction (width direction), and is supported by a support material that is buried in invert concrete at the center portion.
Conventionally, since the floor slab support has a continuous wall structure, the sleepers are obstructive to this, and therefore, after the invert concrete is placed, the floor slab supports are individually installed while being divided into walls. For this reason, installation and removal are complicated, and sleepers for the subsequent carriage and sleepers for transporting the segments are separately required. However, according to the second embodiment, since the wall has a Pca support structure, this problem can be solved.

<Step 2> Invert Concrete Placing FIG. 16 is a diagram showing a step of placing invert concrete as Step 2.
While receiving the subsequent carriage and the segment carriage with an integrated sleeper installed in the same transverse direction (width direction), inverted concrete is placed below as shown in the figure. After the invert concrete has hardened, if it is necessary to receive the rail at the Pca strut position with a sleeper, the sleeper that is separated by the Pca strut and is not integrated in the transverse direction (width direction) is placed between the invert and the camber. It may be installed in such a way as to take a reaction force from Invert (see the lower right figure in FIG. 17).

<Step 3> Floor slab side wall construction and Pca column installation FIG. 17 is a diagram showing a step of constructing a floor slab side wall and installing a Pca column as Step 3.
At the rear of the subsequent carriage, the side wall of the RC floor slab is constructed, and the Pca column 4 is erected on the invert by the portal crane. An anchor or the like is used for the fixing. In addition, since the traveling rail for the following carriage and the traveling rail for the gate crane can share the outermost rail of the sleeper, they do not interfere with the traveling of the segment carriage on the same sleeper inside.

<Step 4> Pca girder installation (every section)
FIG. 18 is a diagram showing a step of installing a Pca girder for each section as step 4.
The Pca girder 3 is installed on the Pca column 4 by a portal crane. At this time, the end faces of the Pca girders 3 are installed with their end faces facing each other, and the projecting reinforcing bars projecting on the Pca struts 4 are passed through the through openings at both ends of the Pca girders 3 (see the upper right diagram in FIG. 19). . As a result, the Pca beam 3 does not fall off from the Pca column 4. Further, the Pca girders 3 are installed on the bottom surface of the Pca support 4 in order to maintain the level (height level) accuracy while passing through the axial direction (longitudinal direction). And adjust the position to a predetermined level.

<Step 5> Placing concrete into the Pca girders (one section)
FIG. 19 is a diagram showing a step of placing, as step 5, a concrete padding (hereinafter referred to as “opening concrete”) in an opening portion of a Pca digit for each section.
When the position of the Pca girders 3 is determined, the interstitial concrete is placed in the through opening (portion iii in the right diagram in the figure) (hatched portion in the right diagram in the figure). As a result, the Pca beam 3 no longer shifts in position.

<Step 6> Joint Placing to Pca Girder FIG. 20 is a diagram showing a step of performing joint bar placement to the Pca girder as Step 6. FIG.
Joint fitting is performed for Pca girder 3. The joint bar arrangement is a binding at a reinforcing bar portion where the Pca girders 3 protrude and wrap.

<Step 7> Placing concrete in the U-shaped groove of Pca girder (every section)
FIG. 21 is a diagram showing a step of placing concrete in the U-shaped groove of the Pca digit for each section as step 7.
Pca girders 3 are completed by placing concrete in the U-shaped grooves of the Pca girders 3 (hatched portions in the right figure of FIG. 21). Since the concrete to be placed in the U-shaped groove is cast on-site, the Pca girder 3 can be reduced in weight, so that the installation efficiency can be improved and the cost of the precast member can be reduced. Further, since the Pca beam 3 span is longer than the conventional Pca wall and the broken line of the level error becomes smooth, the level of the top surface can be maintained with high accuracy, and the installation accuracy of the Pca floor slab can be improved. .

In the case of the conventional Pca wall support, it is difficult to improve the finishing accuracy of the Pca floor slab installation position. Therefore, the level is adjusted with the liner plate, and the Pca floor slab is installed on top of it. Non-shrink mortar was post-filled. As a result, this problem has been solved in exchange for an increase in work period and work cost, but these increases can be eliminated by the step 7.
In addition, if a rubber plate is bonded to the lower side of the Pca floor slab at the production stage in the factory, the installation work is further simplified.

<Step 8> Installation of the first Pca floor slab (every 3 spans)
FIG. 22 is a diagram showing a step of installing the first Pca floor slab 1 every three diameters as step 8.
First, the first Pca floor slab 1 is temporarily installed on the Pca support, and then the second Pca floor slab 2 is temporarily engaged with the concavo-convex shape near the center of the end surface. After that, as a whole, it moves horizontally toward the installed one.
Since the first Pca floor slab 1 is chamfered at four corners (see FIG. 5), when the first Pca floor slab 1 is installed in the axial direction (longitudinal direction) of the second Pca floor slab 2 already installed in the previous row. Even if there is a variation error, it can be installed smoothly if the error is less than the chamfer.
If the anchor bar is inserted into the anchor bar hole provided in the convex portion at the end of the first Pca floor slab 1 and fixed to the mortar on the bearing side, the first Pca floor slab 1 and the second Pca floor slab There is no concern that version 2 will fall out of support. FIG. 28 is an enlarged view showing a state where the anchor bar is inserted into the anchor bar hole of the first Pca floor slab and the mortar is fixed to the bearing side.
The second Pca floor slab 2 is also placed on the bearing in such a manner that the concave shape portion of the inner end portion of the second Pca floor slab 2 meshes with the convex shape portion of the end portion of the first Pca floor slab 1. There is no concern of falling out of support. Further, the protruding bars of the longitudinal line joints of the first and second Pca floor slabs are not positioned and separated by this meshing.

<Step 9> Installation of second Pca floor slab and placement of compacted concrete (every 3 spans)
FIG. 23 is a diagram showing a step of placing the second Pca floor slab 2 for every three spans and placing interstitial concrete as step 9.
The end faces of the second Pca floor slab 2 are installed so that the end faces of the second Pca floor slab 2 are in close contact with the end faces on both sides of the first Pca floor slab 1 of the installed central portion while engaging the respective concave and convex shapes. Subsequently, interstitial concrete is placed between the outer side walls and restrained. During the placement of the interstitial concrete, the second Pca floor slab 2 on both sides and the first Pca floor slab 1 on the center are fixed in the transverse direction (width direction) with a lever block <registered trademark> or the like. This ensures the close contact of the end face described above.
In addition, even if the lower surface and the lower surface of the transverse line joint (refer to the side views shown in FIGS. 5 and 6) are not in close contact with each other in the axial direction (longitudinal direction), the positions of the joint portion concrete described later are not leaked. Just match and match.

<Step 10> Transport of Pca Floor Slab FIG. 24 is a diagram showing a process of transporting the Pca floor slab as Step 10.
Two rows of rails are laid on the outermost edge of the first Pca floor slab 1 installed between the two rows of Pca supports. Thereafter, the carriage for transporting the Pca floor slab is run on the rail, and the Pca floor slab to be installed in the future is transported to the installation location.
Further, when the Pca floor slab is transported by the carriage, a support support may be provided between the Pca floor slab 1 at the center and the invert as necessary.

<Step 11> Joint reinforcement of Pca floor slab (for each section)
FIG. 25 is a diagram showing a step of arranging the joints in the longitudinal line and the transverse line of the Pca floor slab for each section as Step 11.
The first Pca floor slab 1 and the second Pca floor slab are fixed by pulling and fixing the second Pca floor slab 2 and the first Pca floor slab 1 in the central portion in the transverse direction (width direction) with a lever block or the like. 2 Ensure close contact of each end face. Then, a camber or stuffed concrete is placed and restrained between the opposite side walls. Thereby, the end surface of the first Pca floor slab 1 and the end surface of the second Pca floor slab 2, and the end surface of the second Pca floor slab 2 and the facing surfaces of both side walls are brought into close contact with each other.
After this state is reached, the reinforcing bars of the joints (longitudinal line and transverse line) of the Pca floor slab are bound. For vertical line joints, the reinforcing bars are tied together with the main reinforcing bars of the lap joints. Regarding the joint of the transverse line, in the first Pca floor slab 1, the first Pca floor slab 1 adjacent in the axial direction (longitudinal direction) and the left and right second Pca floor slabs adjacent in the transverse direction (width direction). When the left and right second Pca floor slabs 2 are erected while the internal reinforcement of the loop reinforcement of No. 2 is prepared in advance, the internal reinforcements prepared each time are shifted in the transverse direction (width direction) to the left and right respectively. Tie at the correct position. In this way, the inner streaks are expanded and bound for each row in the transverse direction.

<Step 12> Pca floor slab joint placement concrete (per section)
FIG. 26 is a diagram showing a step of placing concrete in the joint portion of the Pca floor slab for each section as step 12. Moreover, in FIG. 29, a mode that concrete is placed in the joint part of a Pca floor slab is expanded and shown.
The interstitial concrete in step 9 described above is an operation of placing by a sequential pump for the purpose of closely contacting and restraining the end face of the second Pca floor slab 2 and the opposite side walls.

On the other hand, in the step 12, the concrete to be cast in the joint part (hereinafter referred to as “joint part concrete”) has a large casting amount and a wide casting range, and therefore is placed by a pump every predetermined span (section). To do. As described above, the transverse line joint is placed on the lower surface of the Pca floor slab (see FIGS. 5 and 6), and the longitudinal line joint is placed on the end surface of the Pca floor slab. This is unnecessary, and the placing operation itself is simple and simple.
In addition, the construction section length of joint part concrete is determined from the workability (for example, one construction length) of the single placement range of joint part concrete.

<Step 13> Completion of Installation of Pca Floor Slab FIG. 27 is a diagram showing a completed image as Step 13.
In the figure, after installation of the Pca slab, the left and right spaces below the Pca slab are used for reciprocating segment transportation, and the upper part of the left and right second Pca slab is used for reciprocating concrete transportation Is shown. That is, in the case of excavation simultaneous construction, the space below the Pca floor slab is occupied by segment transportation except for the central space, so in addition to the transportation of the Pca floor slab, the transport of the joint part concrete is also possible. You will use the top of the plate.

DESCRIPTION OF SYMBOLS 1 ... 1st Pca floor slab, 2 ... 2nd Pca floor slab, 3 ... Pca girder, 4 ... Pca support | pillar

Claims (10)

A Pca floor slab installed at every single diameter between at least one row of bearings continuous in the longitudinal direction and the outer side walls,
The Pca floor slab is composed of a first Pca floor slab installed between a plurality of rows of the bearings and a second Pca floor slab installed between the bearing and any one of the outer side walls,
The first Pca floor slab has a cross-section in a transverse shape, a first bent portion that is bent by a predetermined angle from the horizontal portion of the center portion to both ends, and the root portion of the square shape is the predetermined shape. It is a structure having a second bent portion that is bent backward by an angle to form a horizontal bottom surface, and both end portions that are vertical end surfaces,
Of the structure of the first Pca floor slab, the second Pca floor slab has a shape in which only one side is the second bent portion and the horizontal portion of the central portion extends to the end as it is on the upper surface of the one side. And the structure
The first and second Pca floor slabs have longitudinal line joints composed of reinforcing bars provided on the upper side of the end faces in order to join the Pca floor slabs in the transverse direction, and the Pca floor slabs in the longitudinal direction. A Pca floor slab comprising a transverse line joint made of a reinforcing bar provided on the upper side of the lower surface of the Pca floor slab for joining. The Pca floor slab of claim 1,
The Pca floor slab characterized in that the double reinforcing bars that reach the end through the first bent portion and the second bent portion are fixed and arranged on the double reinforcing bars in the central portion. The Pca floor slab of claim 1,
The first Pca floor slab has a convex portion as a planar shape of the both end portions,
The second Pca floor slab has a concave portion or a convex portion as a planar shape of an end portion opposite to the end portion where the horizontal portion of the central portion extends as it is. The Pca floor slab according to claim 3,
The first Pca floor slab has an anchor bar hole in the convex portion,
The second Pca floor slab has an anchor bar hole in the vicinity of the end where the horizontal portion of the central portion extends as it is. The Pca floor slab according to claim 3,
The convex portion of the first Pca floor slab is disposed at an end surface corner portion,
The Pca floor slab is characterized in that the convex portion of the second Pca floor slab is arranged at an end face corner with a shape that meshes with the convex portion of the first Pca floor slab. The Pca floor slab according to claim 5,
The first or second Pca floor slab has an anchor bar hole in the vicinity of the joint with the first and second Pca floor slabs,
The second Pca floor slab has an anchor bar hole in the vicinity of the end where the horizontal portion of the central portion extends as it is. A method of installing the first or second Pca floor slab according to claim 1 in a transverse direction for each single diameter between at least one row of bearings continuous in the longitudinal direction and both outer side walls. ,
The end face and the end face of the first or second Pca floor slab are brought into close contact with the upper face of the support, and the end face of the second Pca floor slab and the opposite face of the side wall are cambered on the upper face of the outer side walls. A method for installing a Pca floor slab, characterized in that the Pca floor slab is brought into intimate contact with a compacted concrete. A half precast slab installed at every single span between a longitudinally continuous outer support or side wall and at least one row of central support between the support or side wall,
The half precast floor slab has a flat cross section in the transverse direction, and the planar shape of the end face in the transverse direction joined to the half precast floor slab adjacent to the transverse direction has a respective corner angle with the adjacent half precast floor slab. Convex part shape that engages with the part, rebar longitudinal line joint provided on the upper side of the end face in the transverse direction joined to the half precast floor slab adjacent in the transverse direction, and joined to the half precast floor slab adjacent in the longitudinal direction A half precast slab comprising a reinforcing line crossing line joint provided on the upper side of the longitudinal lower surface. A Pca bearing forming a longitudinally continuous row,
The Pca support is composed of Pca struts and Pca girders,
The Pca strut standing on the invert has a reinforcing bar protruding from the top surface of the Pca strut,
The Pca girder installed on the top surface of the Pca column is
A first bent portion having a cross-section in the longitudinal direction and bent at a predetermined angle from the horizontal portion of the central portion to both end portions, and a base portion of the C-shape bent in the reverse direction by the predetermined angle to be a horizontal bottom surface Having a second bent portion that forms a vertical end surface and both ends.
From the both ends to the horizontal bottom surface near the both ends, there is a side wall sandwiching an opening that penetrates vertically in a cross section in the transverse direction, and at least a part from the horizontal bottom surface near the both ends to the central portion is The portion that remains U-shaped in the cross section in the transverse direction is rectangular in the cross section in the transverse direction,
A double rebar that is embedded above and below a horizontal portion of the central portion and horizontally protrudes from the first bent portion to the outside, and is fixed on the double rebar side and is passed from the first bent portion to the second bent portion. A Pca support comprising reinforcing bars arranged along the bends at both ends. A method of installing the Pca support composed of the Pca strut and the Pca girders according to claim 9 in a longitudinal direction,
Adjacent the Pca girders that are adjacent to each other, concrete is placed in the opening of the Pca girders so as to include the protruding portions of the reinforcing bars of the Pca struts, and the Pca girders and the Pca struts are joined and crossed. A first step of forming a U-shaped groove in a directional section;
A Pca bearing having a second step of joining the joints of the Pca girders with a lap joint immediately above the end face of the adjacent Pca girders facing each other, and subsequently placing concrete in the U-shaped groove Installation method.

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