JPH10159227A - Precast concrete floor slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To curtail a construction period, by providing a projection covering the lower face of the joint gap part by butting the bottom of one floor slab end at the connection part of floor slabs in the adjacent floor slab and forming flat the end face of the other floor slab of the connection part. SOLUTION: The reinforcements protruded from the end of connecting floor slabs 21A, 21B are shaped to form a rectangular loop in the thickness direction of the floor slab. And a longer projection 201 than the projected length of the reinforcements 23 rectangularly looped is formed at the bottom of the end of one floor slab 21B and the end face of the other floor slab 21A is formed falt. And pressure-supporting plates 25, 26 piercing respective overlapped parts 24 are arranged at the inside of the ends 22a, 23a of respective rectangularly looped reinforcements 22, 23 overlapped in the longitudinal direction of the connection part of the floor slabs. And further, reinforcements 16 vertically extending to the right angled direction against the overlapped and rectangularly looped reinforcements 22, 23 are arranged. And concrete 8 is placed in the joint gap part 3. Accordingly, the projection covers the joint gap face F to function as the bottom frame and hence, the execution work can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precast concrete slab laid as a slab of a road bridge by connecting adjacent ones via a plurality of reinforcing bars projecting from an end in a bridge axial direction. It is.

[0002]

2. Description of the Related Art Conventionally, bridge slab construction has been carried out by first assembling reinforcing steel, then performing shoring and formwork, and then pouring concrete on site. However, such a construction method cannot save labor and shorten the construction period on site. In recent years, there has been a tendency to adopt a construction method in which a floor slab is precast in advance at a factory and assembled on site.

FIG. 8 is a perspective view showing the entire structure of a precast concrete slab according to a first example of the prior art, FIG. 9 is a longitudinal sectional view showing an enlarged view of a joint thereof, and FIG. FIG. 11 is an overall longitudinal sectional view, and FIG. 11 is a process diagram of the connection operation.

The precast concrete slab of the first conventional example is formed in a flat plate shape and is to be connected to a precast concrete slab (hereinafter simply referred to as a slab) 1A,
A loop reinforcing bar 2 whose tip is formed in an arc shape in the thickness direction of the floor slab protrudes from each end of the bridge axis direction 1B. Further, the bottom of each edge of the floor slab connecting portion is set to be shorter than the projecting length of the loop reinforcing bar 2 and is abutted against each other when the adjacent floor slabs are connected to each other to cover the lower surface of the filling portion 3. Article 1
1a and 11b are protruded. 4 is a bridge girder, 5 is a connecting stud bolt provided on the upper surface of the bridge girder at predetermined intervals, and 6 is a floor slab 1 in which the connecting stud bolt 5 can be fitted.
A and 1B are openings formed in advance, and these openings 6
After each floor slab is connected, concrete is poured.

[0005] In such a case, the construction of the floor slab is performed as follows.
11A to 11C and the procedure of FIG. First, the floor slab 1A is laid first, and the floor slab 1A is laid on the floor slab 1A.
B, the floor slab 1 is connected as shown in FIG.
Hang B down to the same height as floor slab 1A. Then, FIG.
As shown in FIG. 1 (b), move laterally in the direction of the floor slab 1A,
As shown in FIG. 11 (c), the ridge 1 of each floor slab 1A, 1B
The ends of 1a and 11b are abutted with each other via the filling portion 3. Next, as shown in FIG. 9, the reinforcing bars 7 are inserted in a direction perpendicular to the loop reinforcing bars 2 superposed in the longitudinal direction of each floor slab connecting portion to form a joint. 8 is cast on site. Thereby, each floor slab 1A,
1B is integrated.

Another example of a conventional vertical structure of a floor slab (hereinafter referred to as a second conventional example) is disclosed in, for example, Japanese Unexamined Patent Application Publication No.
There is one disclosed in Japanese Patent Application Laid-Open No. 246415/246. This is a precast concrete slab in which ribs extending in the direction perpendicular to the bridge axis are integrally formed on the lower surface. By providing a concavo-convex structure portion and connecting the fitted ribs with each other with a tension member, a compressive force is introduced into the joint portion to form a strong connection portion.

Meanwhile, in a precast concrete slab having a rib on a lower surface in a direction orthogonal to the bridge axis, as the span of the slab increases, the slab main body is required to have high strength and high rigidity. For this reason, at the factory manufacturing stage, a technique of introducing a prestress into a section of the floor slab orthogonal to the bridge axis by using a PC steel wire or the like to obtain a prestressed concrete slab is disclosed in, for example, Japanese Patent Laid-Open No.
No. 102529 (hereinafter, this is referred to as a third conventional example). In the third conventional example, a technique relating to a vertical structure of a floor slab is also disclosed. In the vertical structure of the third conventional slab, the position of the stud for connection with the bridge girder is set to a position that is a vertical portion of the slabs, and each slab is provided with a respective bridge axial end face. By forming a non-slip notch surrounding the connecting stud by abutting each other, and filling a mortar in a box (where the connecting stud is arranged) formed by the abutting of the floor slabs, the floor slabs and the floor slabs are mutually connected. The connection between these and the bridge girder is made.

[0008]

However, the floor slab is formed in a flat plate shape, and at the bottom of each edge of the floor slab connecting portion, a ridge set to be shorter than the length of the loop reinforcing bar is provided. The first conventional example has the following problems. (B) When the floor slab is erected, when the floor slab is suspended and lowered, the planar separation distance between the floor slab and the mating slab to be connected is reduced to the distance of the stuffing part, and the descending side is The ridge of the floor slab overlaps and interferes with the loop reinforcement of the floor slab below. For this reason, when the floor slab is lowered, it is necessary to secure a separation distance between the floor slabs so that the ridges of the floor slab located above are located outside the area of the loop reinforcing bar of the floor slab below. For this reason, it is necessary to perform an operation of laterally moving after descending. When the weight of the floor slab is increased, the lateral moving operation is troublesome, and the construction period cannot be shortened. (B) If the stud bolt for connecting the floor slab and the bridge girder protrudes long, the stud bolt hinders the lateral slab from moving laterally. (C) When the span of the floor slab is large, the slab thickness alone becomes excessively large and the weight (dead load) increases only with the reinforced concrete structure. This dead load can be reduced by introducing a prestress into the entire floor slab using a PC steel wire or the like to increase the strength, but in this case, economic efficiency is impaired.

Further, ribs integrally formed on the lower surface and extending in the direction orthogonal to the bridge axis are set at the positions of the longitudinal portions at both ends in the bridge axis direction,
In the second conventional example in which the concave and convex structure portions formed on the ribs serving as the vertical portions are fitted in a tenon form, and the fitted ribs are connected to each other by a tension member, the connection by the tension member is used. Work must be performed on the lower surface side of the floor slab, and there is a problem in safety.

[0010] Further, the position of the stud for connection with the bridge girder is set to a position which is a vertical portion between the floor slabs, and the connection stud is surrounded by the non-slip notch formed in each floor slab. In the third conventional example in which the slabs are connected to each other and to the bridge girder by filling the mortar, the connection of the respective slabs in the bridge axis direction is not provided in the notch. Since only the mortar is filled, the vertical portion becomes a weak point when viewed from the entire floor slab.

[0011] A first technical problem of the present invention is that when a slab is erected, when the slab is hung down, the slab is lowered with a planar separation distance from a mating slab to be connected close to the distance of the filling portion. The object of the present invention is to make it possible to shorten the construction period by making it unnecessary to perform the lateral movement work after the descent.

A second technical problem of the present invention is that the prestress put into the floor slab can be reduced, and the width of the filling portion can be reduced, and the rebar tension between the floor slabs can be sufficiently increased even when cast-in-place concrete is used. Is to be able to communicate.

[0013]

A precast concrete slab according to claim 1 of the present invention has a structure in which the length of the reinforcing bar projecting from the slab is provided at the bottom of one of the slab edges of the slab connecting portion. A ridge that is set to be long and covers the lower surface of the filling portion by abutting against an adjacent slab is provided, and the other slab end surface of the connecting portion is configured to be a flat surface.
In the invention of claim 1, for example, one of the connecting portions formed on both ends of the floor slab alone in the bridge axis direction is configured as a connecting portion with a ridge, and the other is configured as a connecting portion with a flat surface. When the floor slab is erected, the slab is laid so that the protruding connecting portion comes to the extension side, and is connected to the extension slab to be assembled later. If the floor slabs are connected in such an arrangement,
The flat surface connecting part of the extension slab to be assembled later will be arranged on the laid slab side. Therefore, when suspending and lowering the extended slab, even if the flat slab is separated from the slab to be connected by a distance closer to the distance of the space between the slabs, the interference with the reinforcing bars of the slab to be connected may occur. Since it does not exist, it is possible to perform the descent work smoothly, and immediately after the descent, it can be shifted to the connection work. For this reason, the lateral movement work after the descent becomes unnecessary, and the construction period can be shortened accordingly. Further, since the lateral movement work after the descent becomes unnecessary, the stud bolt for connecting the floor slab and the bridge girder can be set long, and the connection strength between the floor slab and the bridge girder can be increased.

In the precast concrete slab according to the second aspect of the present invention, the length of the reinforcing bar protruding from the slab is set to be longer at the bottom of one slab edge of the slab connecting portion. The first ridge is provided, and the bottom of the other slab edge of the connecting portion is set to be shorter than the projecting length of the reinforcing bar protruding from the slab, and when the butt collides with the adjacent slab. A second ridge is provided to cover the lower surface of the filling portion together with the first ridge by being brought into contact with the first ridge. In the second aspect of the invention, for example, one of the connecting portions formed at both ends of the floor slab alone in the bridge axis direction is configured as a connecting portion with a long ridge, and the other is configured as a connecting portion with a short ridge. When the floor slab is erected, it is laid so that a connecting portion with a long ridge is provided on the extension side, and is connected to an extended floor slab to be assembled later. If the floor slabs are connected in such an arrangement, the connecting portions with the short protrusions of the extended floor slab to be assembled later will be arranged on the laid slab side. Therefore, when the extended floor slab is hung down, even if the flat slab is separated from the floor slab to be connected to the distance of the filling portion and lowered, it may interfere with the reinforcing bar of the connected floor slab. It is gone and I can do the descent work smoothly,
Immediately after the descent, you can move on to the connection work. For this reason, the lateral movement work after the descent becomes unnecessary, and the construction period can be shortened accordingly. Furthermore, since the horizontal movement work after descent is no longer necessary,
The stud bolt for connecting the floor slab and the bridge girder can be set long, and the connection strength between the floor slab and the bridge girder can be increased.

Further, in the precast concrete slab according to claim 3 of the present invention, a reinforcing bar protruding from an end of the slab is formed in a rectangular loop shape in the thickness direction of the slab, and at the time of connection, each connecting portion of the slab is connected. A connecting member disposed inside the opposite end of each of the rectangular loops surrounded by the rectangular loop-shaped reinforcing bars overlapped in the longitudinal direction, each of which extends in the longitudinal direction and penetrates each overlapping portion. It is configured so as to be connected with concrete cast in the section. According to the third aspect of the present invention, the rectangular loop-shaped rebar is anchored to the concrete portion having a rectangular cross section surrounded by the supporting material via the supporting material. Since the concrete bearing stress (concrete compressive force per unit area) changes depending on the area of the bearing material, the area of the bearing material is determined so that the bearing force balanced with the reinforcing steel tensile force is secured in the concrete portion. In any case, the compressive force generated inside the loop of the rectangular loop-shaped rebar is distributed to the concrete by distribution of pressure by the support plate, so that the load on the concrete part can be reduced by that much and the required concrete strength can be reduced. It is possible to sufficiently transmit the rebar tension between the floor slabs while keeping it low. For this reason, the space | interval of a filling part can be compressed conventionally, and the cast-in-place concrete pouring amount of a vertical part can be reduced.

Further, the precast concrete slab according to claim 4 of the present invention is characterized in that as a supporting member used at the time of connection,
A strip-shaped steel plate, a perforated steel plate, a steel plate with protrusions, a steel plate with dowels, or expanded metal is used. According to the fourth aspect of the present invention, when a belt-shaped steel plate is used as the supporting member, the working is easy, and therefore, the adjustment of the concrete supporting stress, that is, the adjustment of the area of the supporting member is easy. Further, by using a perforated steel plate, a steel plate with protrusions, a steel plate with dowels, or an expanded metal as a supporting material, the adhesion (adhesion) to concrete can be increased.

Further, in the precast concrete slab according to claim 5 of the present invention, a main girder mounted on a bridge girder orthogonally to each other is provided on a lower surface of the floor slab, and a prestress is provided inside the main girder by a steel material. It is introduced. According to the fifth aspect of the present invention, since the main girder mounted on the bridge girder at right angles to each other is provided on the lower surface of the floor slab, the prestress (steel material) put into the floor slab can be reduced. Therefore, it is possible to reduce the weight while securing the rigidity of the floor slab, that is, to reduce the thickness of the deck slab of the floor slab.

Further, in the precast concrete slab according to claim 6 of the present invention, an opening into which a stud bolt for connection with a bridge girder can be fitted is provided in a bridge girder portion of at least one main girder among orthogonal main girder. It is provided. According to the sixth aspect of the present invention, since the connection part with the bridge girder is set in the main girder part, the connection with the bridge girder can be strengthened.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, the present invention will be described with reference to the illustrated embodiments. FIG. 1 is a longitudinal sectional view showing a joint portion of a precast concrete floor slab according to a first embodiment of the present invention, FIG. 2 is a side view showing a state in which the floor slab is connected, including a partial sectional view, and FIG. FIG. 4 is a perspective view showing a state where the floor slab is connected, and FIG.
FIG. 5 is a front view of the floor slab, FIG. 5 is a plan view of the floor slab connected thereto, taken along line AA in FIG. 4, and FIG. In each figure, the same reference numerals are given to portions corresponding to the above-described conventional example.

In the precast concrete slab of this embodiment, reinforcing bars (extending from the main reinforcing bars) projecting from the ends of the slabs 21A and 21B to be connected are formed in a rectangular loop shape in the thickness direction of the slab. At the bottom of the edge of one of the floor slabs (here, floor slab 21B), a ridge 201 set longer than the projecting length of the rectangular loop-shaped reinforcing bar 23 protruding from the floor slab 21B is provided. At the same time, the other end surface of the floor slab is formed as a flat surface 202. At the time of these connections, the connecting portion longitudinal portions are respectively provided inside the opposing ends 22a and 23a of the rectangular loops surrounded by the rectangular loop reinforcing bars 22 and 23 superposed in the longitudinal direction of the floor slab connecting portions. The support members 25, 26 made of strip-shaped steel plates, which extend in the direction and penetrate the overlapping portions 24, are arranged.
Reinforcing reinforcing bars 16 extending in a direction perpendicular to these reinforcing bars are arranged above and below 23, and concrete 8 is poured into the filling portion 3.

More specifically, the ridge 201 covers the lower surface of the filling portion 3 by abutting against the adjacent floor slab 21A, and functions as a bottom formwork of the filling portion 3. For this reason, the construction of the shoring work and the formwork work are simplified, and the concrete placing work on the site becomes easy. In addition, it is desirable to attach a seal rubber or the like to the abutting portion between the adjacent floor slabs, thereby improving the sealing property and preventing the concrete to be poured from leaking.

As the concrete 8 to be poured into the filling portion 3, concrete used for conventional cast-in-place concrete (generally, a design standard strength of 200 to 60) is used.
0 kgf / or a cm ^2, range) but, and cracking due to drying shrinkage during filling portion 3 in the present embodiment, in order to improve the cracking resistance to loads received from the traveling vehicle, with fiber reinforced concrete.

In the present embodiment, the support plates 25 and 26 are formed of flat steel cut to an appropriate length in consideration of workability. However, as the supporting plate, the rectangular loop-shaped reinforcing bar 2 is used.
Since it is sufficient that a required cross-sectional area for distributing the pressure received from 2, 23 can be ensured, a perforated flat steel plate may be used. Further, those obtained by attaching projections or dowels to these flat steels may be used. Further, an expanded metal as shown in FIG. 6 may be used in which a flat steel is slit and expanded to form a lattice. Thus, the support plate 25,
By using a perforated flat steel, a flat steel with projections or dowels, or an expanded metal as 26, the adhesion (adhesion) to the concrete 8 can be increased.

The precast concrete slab of the present embodiment has a rectangular main girder 31 which is placed on the bridge girder 4 at right angles to the lower surface of each floor slab 21 as shown in FIGS. , 32, 33, 34, and a steel material 3 inside the main girder.
5 introduces prestress. Here, the main girders 31, 32 in the direction perpendicular to the bridge axis, which function as horizontal ribs, are P
The prestress is introduced by a C steel bar or a PC steel wire, and the main girder 33, 34 in the bridge axis direction functioning as a vertical rib partially protrudes outward to form the rectangular rebars 22, 23. 36 and a reinforced concrete structure. As a result, the prestress (steel material) put into the floor slab 21 can be reduced, and the rigidity of the floor slab 21 can be secured and the weight can be reduced, that is, the thickness of the deck slab 37 of the floor slab 21 can be reduced. .

The position of the main girder 33, 34 in the bridge axis direction at right angles to the bridge axis is set to the bridge girder 4 position.
4 is provided with an opening 38 into which a stud bolt (see FIG. 8) for connection with the bridge girder 4 can be fitted. Thereby, the connection part with the bridge girder 4 could be set to the main girder part, and the joint with the bridge girder 4 could be strengthened.

In the precast concrete slab of the present embodiment, the slab 21 is laid such that a connecting portion with the ridge 201 is provided on the extension side, and is connected to an extended slab to be assembled later. If the floor slabs are connected in such an arrangement, the flat surface 202 of the extended floor slab to be assembled later can be used.
The connecting portion is arranged on the laid slab side. Therefore, when the extended floor slab is hung down, the rectangular loop-shaped reinforcing bar 23 of the mating floor slab to be connected can be lowered even if the planar separation distance from the mating floor slab to be connected is lowered close to the distance of the filling portion.
Since there is no interference with the work, the descending operation can be performed smoothly, and immediately after the descending operation, the connecting operation can be started.
For this reason, the lateral movement work after descent becomes unnecessary, and
The construction period can be shortened. Further, since the lateral movement work after the descent becomes unnecessary, the stud bolt for connecting the floor slab 21 and the bridge girder 4 can be set longer, and the connection strength between the floor slab 21 and the bridge girder 4 can be increased. .

The rectangular loop-shaped reinforcing bars 22 and 23 assembled in a tenon form are anchored and fixed to the concrete section having a rectangular cross section surrounded by the support plates 25 and 26 via the support plates 25 and 26 to form a rectangular loop shape. Since the compressive force generated inside the loops of the rebars 22 and 23 is transmitted to the concrete 8 by distributing the pressure by the supporting plates 25 and 26, the load on the concrete 8 can be reduced correspondingly and the required concrete strength can be reduced. It is possible to sufficiently transmit the rebar tension between the floor slabs while keeping it low. For this reason, the space | interval of the filling part 3 can be compressed conventionally, and the cast-in-place concrete pouring amount of a vertical part can be reduced.

In the above-described embodiment, the main girder mounted on the bridge girder at right angles to each other has been described as an example in which the main girder is rectangularly arranged. However, the main girder may be arranged in a cross shape or a polygonal shape. Also, the opening in which the connecting stud bolt can be inserted may be provided in any main girder as long as it is formed in the bridge girder portion of the main girder, and the number of openings is set at a plurality of positions in the bridge axis direction. Is also good. In any case, the same operation and effect as those of the above-described embodiment can be obtained.

Embodiment 2 FIG. 7 is a longitudinal sectional view showing a joint part of a precast concrete floor slab according to a second embodiment of the present invention. In the drawing, the same reference numerals are used for parts corresponding to the above-described first embodiment (FIG. 1). It is attached.

In the precast concrete slab of this embodiment, a ridge functioning as a bottom form of the filling portion 3 is connected to one of the slabs 21A and 21B to be connected (here, the slab 21).
B) provided at the bottom of the edge of the first slab 201A, which is longer than the length of the protrusion of the rectangular loop-shaped reinforcing bar 23 on the side of the floor slab 21B, and the edge of the other floor slab 21A. And a second ridge 201B which is provided at the bottom of the portion and is set to be shorter than the projecting length of the rectangular loop-shaped reinforcing bar 22 on the floor slab 21A side. This is the same as that of the embodiment.

In the precast concrete slab of this embodiment, the slab 21 is erected by extending the first
The extension slab to be laid so that the connecting portion with the ridge 201A comes and to be assembled later is the first ridge 201A of the laid slab.
These connections are made such that the short connecting portion with the second ridge 201B is located on the side facing the connecting portion. If the floor slabs are connected in such an arrangement, the connecting portion with the second ridge 201B of the extended floor slab to be assembled later will be arranged on the laid slab side. Therefore, when the extended floor slab is hung down, even when the planar slab to be connected to the floor slab to be connected is lowered close to the distance of the filling portion, the rectangular loop-shaped rebar 23 of the connected floor slab is connected to the floor slab. Since there is no obstacle, the descent operation can be performed smoothly, and immediately after the descent, the connection operation can be started. For this reason, the lateral movement work after the descent becomes unnecessary, and the construction period can be shortened accordingly. Further, since the lateral movement work after the descent becomes unnecessary, the stud bolt for connecting the floor slab 21 and the bridge girder 4 can be set longer, and the connection strength between the floor slab 21 and the bridge girder 4 can be increased. .

[0032]

As described above, according to the first aspect of the invention, the bottom of one of the slab edges of the slab connecting portion is longer than the projecting length of the reinforcing bar projecting from the slab. A ridge that covers the lower surface of the filling portion is provided by abutting against the set and adjacent floor slab, and the other floor slab end face of the connecting portion is configured as a flat surface. It is not necessary to perform the lateral movement work after hanging and lowering the construction time, and the stud bolt for connecting the floor slab and the bridge girder can be set longer, and the connection between the floor slab and the bridge girder Strength can be increased.

According to the second aspect of the present invention, the first slab end portion of the slab connecting portion is provided at the bottom of the first slab with a length longer than the length of the reinforcing bar projecting from the slab. A ridge is provided, and the first ridge is set at the bottom of the other edge of the slab of the connecting portion to be shorter than the protruding length of the reinforcing bar protruding from the slab, and abuts against the adjacent slab. A second covering the lower surface of the filling portion together with the first ridge by being abutted.
Since the ridges are provided, it is not necessary to traverse the work after hanging down the extension slab when installing the slab.
The construction period can be shortened, and the stud bolt for connecting the floor slab and the bridge girder can be set longer, and the connection strength between the floor slab and the bridge girder can be increased.

According to the third aspect of the present invention, the reinforcing bar projecting from the end of the floor slab is formed in a rectangular loop shape in the thickness direction of the floor slab. The support members which are arranged inside the opposite ends of the rectangular loops surrounded by the rectangular loop-shaped reinforcing bars and extend in the longitudinal direction of the connecting portions and penetrate the respective overlapping portions, and are put into the filling portions. The rectangular loop-shaped rebar is anchored to the rectangular cross-section concrete part surrounded by the supporting material via the supporting material, and is fixed inside the loop of the rectangular loop-shaped reinforcing steel. The generated compressive force is transmitted to the concrete by distributing the pressure by the support plate. For this reason, the load on the concrete portion can be reduced, and the reinforcing steel tensile force between the floor slabs can be sufficiently transmitted while the required concrete strength is kept low. Further, the interval between the filling portions can be reduced as compared with the conventional case, and the amount of cast-in-place concrete in the vertical portion can be reduced.

According to the fourth aspect of the present invention, since the belt-shaped steel plate, the perforated steel plate, the steel plate with projections, the steel plate with dowels, or the expanded metal is used as the supporting material used at the time of connection, processing is easy. In addition, the adjustment of the concrete bearing stress becomes easy. Further, a perforated steel plate, a steel plate with projections, a steel plate with dowels, or an expanded metal as a supporting material contributes to enhancing the adhesion (adhesion) to concrete.

According to the fifth aspect of the present invention, a main girder mounted on a bridge girder at right angles to each other is provided on the lower surface of the floor slab.
Since the prestress is introduced by the steel material inside the main girder, the prestress (steel material) to be put into the floor slab can be reduced. Therefore, it is possible to reduce the weight while securing the rigidity of the floor slab, that is, to reduce the thickness of the deck slab of the floor slab.

According to the sixth aspect of the present invention, an opening is provided at the bridge girder portion of one of the orthogonal main girder so that a stud bolt for connection with the bridge girder can be fitted. Can be set to the main girder part, and the connection with the bridge girder can be strengthened.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a joint portion of a precast concrete floor slab according to a first embodiment of the present invention.

FIG. 2 is a side view showing a state in which a precast concrete slab according to the first embodiment is connected, including a partial cross-sectional display.

FIG. 3 is a perspective view showing a state where a precast concrete slab according to the first embodiment is connected.

FIG. 4 is a front view of the precast concrete slab according to the first embodiment.

FIG. 5 is a plan view along the line AA of FIG. 4 showing a state in which the precast concrete slab according to the first embodiment is connected.

FIG. 6 is a front view showing an example of a supporting member used when connecting the precast concrete floor slab joints according to the first embodiment.

FIG. 7 is a longitudinal sectional view showing a joint of a precast concrete slab according to a second embodiment of the present invention.

FIG. 8 is a perspective view showing the entire configuration of a conventional precast concrete slab.

FIG. 9 is an enlarged longitudinal sectional view showing a joint part of a conventional precast concrete floor slab.

FIG. 10 is an overall vertical sectional view showing the arrangement of reinforcing bars of a conventional precast concrete slab.

FIG. 11 is a process chart of a connection operation of a conventional precast concrete slab.

[Explanation of symbols]

 3 Filling part 4 Bridge girder 5 Stud bolt for connection 8 Concrete 21, 21A, 21B Precast concrete floor slab 22, 23 Rectangular loop-shaped reinforcing bar (rebar) 22a, 23a Opposite ends of rectangular loop 24 Rectangular loop-shaped reinforcing bar overlapping portion 25, 26 Bearing material 31, 32, 33, 34 Main girder 35 Steel material 38 Opening 201 Projection 201A First projection 201B Second projection 202 Flat surface

Claims (6)

[Claims] 1. A precast concrete floor slab laid as a floor slab of a road bridge by being connected between adjacent ones via a plurality of reinforcing bars projecting from a bridge axial direction end portion, wherein: At the bottom of one edge of the floor slab, a ridge is provided that is longer than the projecting length of the reinforcing bar projecting from the floor slab and covers the lower surface of the filling portion by abutting against an adjacent floor slab. A precast concrete slab, wherein the other slab end face of the connecting portion is formed as a flat surface. 2. A precast concrete slab laid as a slab of a road bridge by being connected between adjacent ones via a plurality of reinforcing bars projecting from a bridge axial direction end, At the bottom of one edge of the floor slab, a first ridge set to be longer than the projecting length of the reinforcing bar projecting from the floor slab is provided, and the other edge of the floor slab of the connecting portion is provided. The bottom portion is set to be shorter than the length of the reinforcing bar projecting from the floor slab, and is strung together with the first ridge at the time of colliding with the adjacent slab. A precast concrete slab, wherein a second ridge is provided to cover a lower surface of the part. 3. A reinforcing bar projecting from an end of the slab is formed in a rectangular loop shape in the thickness direction of the slab, and at the time of connection, the reinforcing members are formed by the rectangular loop reinforcing bars superposed in the longitudinal direction of the connecting portions of the slab. The connecting members arranged inside the opposite ends of the enclosed rectangular loops, each extending in the longitudinal direction of the connecting portion, penetrating each overlapping portion, and being connected by the concrete poured into the filling portion. Claim 1 or Claim 2
The described precast concrete floor slab. 4. A supporting material used for connection is a strip-shaped steel sheet, a perforated steel sheet, a steel sheet with a projection, a steel sheet with a dowel, or an expanded metal.
The described precast concrete floor slab. 5. A main girder mounted on a bridge girder orthogonal to each other on a lower surface of a floor slab, and a prestress is introduced into the main girder by a steel material. The precast concrete floor slab according to any one of the above. 6. The precast concrete according to claim 5, wherein at least one main girder of the orthogonal main girder has an opening through which a stud bolt for connection to the bridge girder can be fitted. Floor slab.