JP2017106231A - Pca floor slab joint structure and construction method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of cracks of concrete and reduce reinforcement assembly work amount and concrete installation amount at the site in a PCa floor slab joint structure.SOLUTION: Lower reinforcement bars 27 are disposed below an overlapping part of a first lower joint reinforcement 21L and a second lower joint reinforcement 22L, which extend from facing joint ends of PCa floor slabs 8 disposed in proximity, so as to overlap and continue in a direction perpendicular to the bridge axis. The lower reinforcement bars surround multiple first lower joint reinforcements 21L and second lower joint reinforcements 22L on three sides. Upper reinforcement bars 28 are disposed above the overlapping part of a first upper joint reinforcement 21U and a second upper joint reinforcement 22U, which extend from the facing joint ends, so as to overlap and continue in the direction perpendicular to the bridge axis. The upper reinforcement bars surround multiple first upper joint reinforcements 21U and the second upper joint reinforcements 22U on three sides.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a joint structure of a PCa floor slab (precast concrete floor slab) and a construction method thereof.

  Some bridge slabs are constructed by arranging a plurality of PCa floor slabs on a bridge girder so as to be aligned in the direction of the bridge axis and integrating the PCa floor slabs adjacent to each other. An RC loop joint is widely used as such a PCa floor slab joint structure (see FIGS. 15 and 16 of Patent Document 1). In the PCa floor slab using RC loop joints, a plurality of looped reinforcing bars are arranged so as to extend from the joining end surface of the floor slab body at intervals in the direction perpendicular to the bridge axis so that the looped reinforcing bars are embedded. It is formed by placing concrete. The looped reinforcing bar is curved so as to draw an arc in the thickness direction of the PCa floor slab, and is formed in an extension dimension that overlaps with the looped reinforcing bar of the PCa floor slab that is disposed in proximity. Then, reinforcing reinforcing bars extending in the direction perpendicular to the bridge axis are disposed inside the closed cross-section portion formed by the loop-shaped reinforcing bars of the pair of PCa floor slabs arranged in proximity, and the floor slabs of both PCa floor slabs in this state The RC loop joint is constructed by placing concrete between the main bodies.

  However, in this RC loop joint, the reinforcing bars cannot be arranged inside the loop-shaped reinforcing bars in advance before the PCa floor slab is arranged, and after the pair of PCa floor slabs are arranged at predetermined positions, the loop-shaped reinforcing bars are not arranged. Reinforcing bars must be inserted inside the bars. Therefore, the construction was complicated. Therefore, in the precast floor slab described in Patent Document 1, the looped reinforcing bars that protrude from the floor slab body in the direction of the bridge axis are replaced with upper joint reinforcing bars and lower joint reinforcing bars each having an end band at the tip, and these joint reinforcing bars are used. Are arranged at intervals in the vertical direction and the direction perpendicular to the bridge axis. Is also recessed to form a temporary storage groove for reinforcing reinforcing bars (see Patent Document 1).

JP 2012-62664 A

  However, in the joint structure of Patent Document 1, only a reinforcing reinforcing bar is disposed between the upper joint reinforcing bar and the lower joint reinforcing bar. Therefore, when a support pressure is applied to the end band of the upper joint reinforcing bar or the lower joint reinforcing bar, There is a risk of cracks occurring in the concrete above the joint rebar and below the lower joint rebar. Moreover, in the joint structure of patent document 1, it is not necessary to insert a reinforcement reinforcement between upper and lower joint reinforcement after arrangement | positioning of a PCa floor slab, but the reinforcement reinforcing bar temporarily placed is suitable after arrangement | positioning of a PCa floor slab. In-situ rebar assembly work is required to place it in position. Furthermore, since the upper end face of the floor slab body needs to be recessed from the lower end face in order to temporarily place the reinforcing bars, the size of the joint in the axial direction of the bridge increases, and the amount of concrete to be placed on the joint at the site is large. Become.

  In view of such a background, the present invention provides a joint structure of a PCa slab that can suppress the occurrence of cracks in concrete and can reduce the amount of rebar assembling work and the amount of concrete placement on site, and a construction method thereof. Let it be an issue.

  In order to solve the above problems, the joint structure (10) of the PCa floor slab (8) according to the present invention includes a first joint end face extending in a direction perpendicular to the bridge axis in the first PCa floor slab (8A) ( 12A) a plurality of first upper rebars (21U) arranged at intervals in the direction perpendicular to the bridge axis so as to extend from the upper part (12U) and the lower part (12L) of the bridge 12A, each having a fixing part (23) at the tip. ) And a plurality of first lower joint reinforcing bars (21L), and a second PCa floor slab (8B) disposed close to the first PCa floor slab (8A) with a gap (G) in the bridge axis direction. ) In the direction perpendicular to the bridge axis so as to extend from the upper part (12U) and the lower part (12L) of the second joint end face (12B) facing the first joint end face (12A). , Each having a fixing portion (23) at the tip, and the corresponding A plurality of second upper joint rebars (22U) and a plurality of second lower joint rebars (22L) having an extension length overlapping with one upper joint rebar (21U) or the first lower joint rebar (21L); A lower restraint portion (27a) extending in a direction perpendicular to the bridge axis below the overlapping portion of the first lower joint reinforcement (21L) and the second lower joint reinforcement (22L), and the lower restraint portion (27a). A pair of first extending upward from both ends of the lower restraining portion (27a) so as to surround the plurality of first lower joint reinforcing bars (21L) and the second lower joint reinforcing bars (22L) from three directions. A plurality of lower reinforcing bars (27) including one side restraint part (27b) and continuously extending in the direction perpendicular to the bridge axis, the first upper joint reinforcing bar (21U) and the second The overlapping parts of the upper joint rebar (22U) In cooperation with the upper restraint portion (28a) extending in the direction perpendicular to the bridge axis and the upper restraint portion (28a), a plurality of the first upper joint reinforcing bars (21U) and the second upper joint A pair of second side restraint portions (28b) extending downward from both ends of the upper restraint portion (28a) so as to surround the reinforcing bar (22U) from three directions, and overlapping in the direction perpendicular to the bridge axis A plurality of upper reinforcing bars (28) provided continuously, the first upper joint reinforcing bar (21U), the first lower joint reinforcing bar (21L), the second upper joint reinforcing bar (22U), and the second lower reinforcing bar. It is set as the structure provided with the joint concrete (13) constructed | assembled in the said clearance gap (G) so that a joint reinforcement (22L), the said lower reinforcement (27), and the said upper reinforcement (28) may be wound.

  Moreover, in order to solve the said subject, the construction method of the joint structure (10) of the PCa floor slab (8) based on this invention is the upper part of the 1st joining end surface (12A) extended in a bridge axis orthogonal direction, A plurality of first upper joint rebars (21U) and a plurality of first lower joint rebars (21L) which are arranged at intervals in a direction perpendicular to the bridge axis so as to extend from the lower part and each have a fixing portion at the tip. 1 PCa floor slab (8A) is prepared, and arranged in the direction perpendicular to the bridge axis so as to extend from the upper part and the lower part of the second joint end face (12B) extending in the direction perpendicular to the bridge axis A second PCa floor slab (8B) comprising a plurality of second upper joint reinforcing bars (22U) and a plurality of second lower joint reinforcing bars (22L) each having a fixing portion at the tip thereof, and the bridge shaft A lower restraint portion (27a) extending in a perpendicular direction, and Preparing a plurality of lower reinforcing bars (27) including a pair of first side restraint portions (27b) extending upward from both ends of the lower restraint portion (27a), and extending in a direction perpendicular to the bridge axis. Preparing a plurality of upper reinforcing bars (28) including an upper restraint portion (28a) and a pair of second side restraint portions (28b) extending downward from both ends of the upper restraint portion (28a); A gap (G) between the step of placing the first PCa floor slab (8A) at a predetermined position on the bridge beam and the second joint end face (12B) and the first joint end face (12A) Are formed, the second upper joint reinforcing bar (22U) overlaps with the first upper joint reinforcing bar (21U), and the second lower joint reinforcing bar (22L) overlaps with the first lower joint reinforcing bar (21L). , At a position close to the first PCa floor slab (8A) on the bridge girder The step of arranging the second PCa floor slab (8B), and the lower restraining portion (27a) below the overlapping portion of the first lower joint reinforcing bar (21L) and the second lower joint reinforcing bar (22L) A plurality of the first lower joint reinforcing bars (21L) and the second lower joint reinforcing bars (22L) are positioned by the lower restraint part (27a) and the pair of first side restraint parts (27b). A step of arranging the lower reinforcing bar (27) so as to surround from the side, and the upper restraint portion (28a) of the portion where the first upper joint reinforcing bar (21U) and the second upper joint reinforcing bar (22U) overlap each other. A plurality of the first upper joint reinforcing bars (21U) and the second upper joint reinforcing bars (22U) which are located above and are formed by the upper restraint portion (28a) and the pair of second side restraint portions (28b). The upper reinforcement bars (2 8) arranging the first upper joint rebar (21U), the first lower joint rebar (21L), the second upper joint rebar (22U), the second lower joint rebar (22L), the lower Constructing joint concrete (13) in the gap (G) so as to involve the reinforcing bars (27) and the upper reinforcing bars (28), and arranging the lower reinforcing bars (27), It is performed before the step of arranging the first PCa floor slab (8A), and the step of arranging the upper reinforcing bar (28) is performed before the step of arranging the second PCa floor slab (8B). Configuration.

  According to these configurations, the first and second lower joint reinforcing bars are restrained by the lower reinforcing bars, the first and second upper joint reinforcing bars are restrained by the upper reinforcing bars, and the restraining force of the joint concrete is increased. It is possible to suppress cracks in the concrete due to the bearing pressure. In addition, the first PCa floor slab is disposed in a state where the lower reinforcing bar is preliminarily assembled to the first PCa floor slab, and the second PCa floor slab is preliminarily assembled to the second PCa floor slab. Therefore, the amount of rebar assembly work on site can be reduced. Furthermore, since the lower reinforcing bar and the upper reinforcing bar can be arranged at predetermined positions without the concave portions of the first joint end face and the second joint end face, the amount of concrete placement on site can be reduced.

  In the above invention, the lower reinforcing bar (27) extends from the upper end of the first side restraint portion (27b) in the vicinity of the first upper joint reinforcing bar (21U) and extends in the bridge axis direction. 1st extension part (27c), and the upper reinforcement bar (28) is close to the second lower joint reinforcement bar (22L) from the lower end of the second side restraint part (28b). It is good to set it as the structure which further has a pair of 2nd extension part (28c) extended in an axial direction.

  According to this structure, the adhesive force to the joint concrete of the 1st side part restraint part and the 2nd side part restraint part becomes high, and the restraint force of the 1st and 2nd lower joint reinforcement by a lower reinforcement and the upper reinforcement Since the restraining force of the first and second upper joint reinforcing bars can be increased, cracks in the concrete can be effectively suppressed.

  In the above invention, the pair of lower reinforcing bars (27) provided so as to be continuous are provided at the overlapping portion of the lower restraining portion (27a) and at both ends of the overlapping portion. By the pair of first side restraint portions (27b), a plurality of the first lower joint rebars (21L) and a second lower joint rebar (22L), and a plurality of the first upper joint rebars (21U) ) And the second upper joint rebar (22U) from three directions, and a pair of upper reinforcing bars (28) provided so as to be continuous are the overlapping portions of the upper restraint portion (28a), and A plurality of the first upper joint reinforcing bars (21U), the second upper joint reinforcing bars (22U), and a plurality of the second side restraint portions (28b) provided at both ends of the overlapping portion. book of Serial first lower coupling reinforcing bars (21L) and may configured to enclose the said second lower coupling reinforcing bars (22L) on three sides.

  According to this configuration, a plurality of first lower joint reinforcing bars and second lower joint reinforcing bars and a plurality of first upper joint reinforcing bars and second upper joint reinforcing bars are not only one lower reinforcing bar and upper reinforcing bar. Since these overlapping portions are also surrounded from three directions, the restraining force of the first and second lower joint reinforcing bars and the restraining force of the first and second upper joint reinforcing bars by the lower reinforcing bar and the upper reinforcing bar are increased. Can do.

  In the above invention, the first upper joint rebar (21U) and the first lower joint rebar (21L) are provided at positions corresponding to each other in the direction perpendicular to the bridge axis, and the second upper joint rebar ( 22U) and the second lower joint rebar (22L) are provided at mutually corresponding positions different from the first upper joint rebar (21U) and the first lower joint rebar (21L) in the direction perpendicular to the bridge axis, The first upper joint rebar (21U), the second upper joint rebar (22U), the second upper joint rebar (21U) surrounding the overlapping portions of the pair of lower reinforcing bars (27) provided in a continuous manner from three directions. The first lower joint rebar (21L) and the second lower joint rebar (22L) and the first part of the pair of upper reinforcing bars (28) provided so as to be continuous are surrounded by the first side. Upper joint rebar ( 1U), said second upper coupling reinforcing bars (22U), said first lower coupling reinforcing bars (21L) and the second is a lower joint reinforcement (22L), may be at least partially in different configurations.

  According to this configuration, a group of joint reinforcing bars surrounded from three directions by the lower reinforcing bars and a group of joint reinforcing bars surrounded from the three directions by the upper reinforcing bars can be distributed. Thereby, the restraining force with respect to the 1st and 2nd joint reinforcement and joint concrete by a lower reinforcement bar and an upper reinforcement bar can be heightened equally.

  In the above invention, the lower reinforcing bar (27) includes a vicinity of the fixing part of the first lower joint reinforcing bar (21L) and a vicinity of the fixing part of the second lower joint reinforcing bar (22L). Arranged in a plurality of rows in the axial direction, the upper reinforcing bars (28) are located in the vicinity of the fixing portion of the first upper joint reinforcing bar (21U) and in the vicinity of the fixing portion of the second upper joint reinforcing bar (22U). It is good to set it as the structure arrange | positioned in the multiple rows of the bridge axis direction including.

  According to this configuration, the overlapping length of the first upper joint reinforcing bar and the second upper joint reinforcing bar, and the overlapping length of the first lower joint reinforcing bar and the second lower joint reinforcing bar are increased, so that these joint concretes While securing adhesive force, the restraining force of the lower reinforcing bar and the upper reinforcing bar can be effectively increased.

  In the above invention, the first lower joint reinforcing bar (21L) and the second lower joint reinforcing bar (22L) extend in a direction perpendicular to the bridge axis below a portion where they overlap each other, and the first lower joint reinforcing bar ( 21L) and the second lower joint reinforcing bar (22L), the lower through bar (25) having a length over the entire length, and the first upper joint reinforcing bar (21U) and the second upper joint reinforcing bar (22U) overlap each other. An upper reinforcing bar (26) extending in a direction perpendicular to the bridge axis above the portion and having a length extending over all of the first upper joint reinforcing bar (21U) and the second upper joint reinforcing bar (22U); It is good to have a configuration provided.

  According to this configuration, the bending strength in the direction perpendicular to the bridge axis of the joint portion can be improved. Moreover, the restraining force with respect to the 1st and 2nd joint reinforcement and joint concrete by a lower reinforcement bar and an upper reinforcement bar can be made equal in a bridge axis right angle direction.

  Thus, according to the present invention, it is possible to provide a joint structure of PCa floor slabs and a construction method thereof that can suppress the amount of rebar assembling work on site and the amount of concrete placement on site.

The schematic perspective view which shows the assembly state of the PCa floor slab which concerns on embodiment Longitudinal sectional view of joint structure of PCa floor slab according to embodiment III-III sectional view in FIG. IV-IV sectional view in Fig. 2 (A) VA-VA cross section in FIG. 2, (B) VB-VB cross section, (C) Cross section in which A and B are combined The perspective view of (A) lower reinforcement bar and (B) upper reinforcement bar shown in FIG. (A) Plane, (B) B cross section, (C) C cross section of PCa floor slab Illustration of assembly procedure for PCa floor slab

  Hereinafter, with reference to the drawings, a joint structure 10 of a PCa floor slab 8 according to an embodiment of the present invention and a construction method thereof will be described in detail.

  FIG. 1 is a schematic perspective view showing an assembled state of a bridge 1 to which a joint structure 10 of a PCa floor slab 8 according to an embodiment is applied. As shown in the figure, the bridge 1 includes a pair of bridge piers 2 (only one pier 2 is shown in the figure) provided apart from each other in the direction of the bridge axis, and a bridge girder 3 spanned between the pair of piers 2. And a floor slab 4 constructed on the bridge girder 3. The bridge 1 may be used as a road bridge and may be used for other purposes. One or both of the pair of piers 2 may be abutments. The bridge girder 3 is arranged on the pier 2 via the support 5. In the present embodiment, the bridge girder 3 is constituted by three parallel beams 6 extending in the bridge axis direction and parallel to each other (not shown) connecting the beams 6 adjacent to each other in the direction perpendicular to the bridge axis. .

  The floor slab 4 is constructed by using a plurality of PCa floor slabs 8 each constituting a floor slab portion divided in the bridge axis direction. Specifically, the floor slab 4 sequentially arranges a plurality of PCa floor slabs 8 close to each other in the bridge axis direction while leaving a gap G, and sequentially constructs a joint structure 10 between a pair of PCa floor slabs 8 that are close to each other. It is constructed by connecting a plurality of PCa floor slabs 8 together. All illustrated PCa floor slabs 8 have the same shape. Different shapes or sizes of PCa floor slabs 8 may be used at the start and end of the bridge girder 3, the joint, and the like. Although not shown, a stud for fixing a floor slab is planted on the upper surface of the bridge girder 3. On the other hand, a fixing hole 9 for fixing the PCa floor slab 8 to the bridge girder 3 is formed at a position corresponding to the stud of the PCa floor slab 8 by receiving the stud and filling the filler in that state. Yes.

  FIG. 2 shows a longitudinal section around the joint structure 10 of the PCa floor slab 8 as seen through the concrete. The hatching of concrete and reinforcing bars is omitted. The same applies to the cross-sectional views of FIG.

  As shown in FIGS. 1 and 2, the PCa floor slab 8 (8A, 8B) includes a floor slab main body 11 made of reinforced concrete. The floor slab body 11 is formed in a plate shape having a substantially rectangular shape that is long in the direction perpendicular to the bridge axis in plan view. One end surface and the other end surface in the bridge axis direction of the floor slab main body portion 11 are joint end surfaces 12 (12A, 12B) with the PCa floor slab 8 arranged close to each other in the bridge axis direction. Hereinafter, the PCa floor slab 8 that is located on the left side in FIG. 2 and is arranged first at a predetermined position on the bridge girder 3 is referred to as a first PCa floor slab 8A, and is located on the right side in FIG. The PCa floor slab 8 to be disposed later at a predetermined position on the bridge girder 3 adjacent to the PCa floor slab 8A is referred to as a second PCa floor slab 8B. When they are not distinguished from each other, they are simply referred to as PCa floor slab 8. Further, the end face on the second PCa floor slab 8B side (the right side in FIG. 2) of the first PCa floor slab 8A arranged first is referred to as a first joining end face 12A, and the second PCa floor slab 8B arranged later The end surface of the PCa floor slab 8B on the first PCa floor slab 8A side (left side in FIG. 2) is referred to as a second joining end surface 12B. When they are not distinguished from each other, they are simply referred to as a joining end surface 12.

  As shown in FIG. 2, the joining end faces 12 of the PCa floor slabs 8 extend in a direction perpendicular to the bridge axis, and extend in a bridge axis direction with respect to a joining surface lower part 12L and a joining surface lower part 12L extending substantially vertically. The connecting surface upper portion 12U extends substantially vertically at the recessed position, and the connecting surface lower portion 12L and the connecting surface upper portion 12U are connected to each other, and the connecting surface intermediate portion 12M extends obliquely. Thereby, the gap G between the first joint end face 12A of the first PCa floor slab 8A arranged at a predetermined position and the second joint end face 12B of the second PCa floor slab 8B is higher than the lower part. It has become wide. The concrete is poured into the gap G and hardens to become the joint concrete 13.

  The PCa floor slab 8 includes a plurality of first lower joint reinforcing bars 21L and a plurality of first upper joint reinforcing bars 21U provided integrally with the floor slab body 11 so as to extend from the first joining end face 12A, and a second A plurality of second lower joint reinforcing bars 22L and a plurality of second upper joint reinforcing bars 22U provided integrally with the floor slab body 11 so as to extend from the joint end face 12B. Hereinafter, the first lower joint bar 21L and the first upper joint bar 21U are collectively referred to as a first joint bar 21, and the second lower joint bar 22L and the second upper joint bar 22U are combined to form a second joint bar 22; The first joint rebar 21 and the second joint rebar 22 are collectively referred to as joint rebars 21 and 22. The joint reinforcing bars 21 and 22 extend in the bridge axis direction and constitute the main reinforcing bar of the floor slab 4.

  A fixing portion 23 having an enlarged diameter is integrally provided at the tips of all the joint reinforcing bars 21 and 22. The fixing unit 23 may be configured by an end band attached to the tips of the joint reinforcing bars 21 and 22, and the tips of the joint reinforcing bars 21 and 22 are enlarged when the joint reinforcing bars 21 and 22 are manufactured or processed after the manufacturing. You may be comprised by the enlarged diameter part formed. The fixing unit 23 is expanded in diameter with respect to the joint reinforcing bars 21 and 22, so that when the compressive force or tensile force in the bridge axis direction is applied to the joint reinforcing bars 21 and 22, the supporting pressure is transmitted to the joint concrete 13. The fixing force with respect to the joint concrete 13 of the joint reinforcing bars 21 and 22 is improved.

  The first lower joint reinforcing bar 21L extends from the joining surface lower part 12L of the first joining end face 12A, and is arranged at a predetermined interval in the direction perpendicular to the bridge axis. The first upper joint reinforcing bar 21U extends from the joining surface upper part 12U of the first joining end face 12A, and is the same in the direction perpendicular to the first lower joint reinforcing bar 21L at a predetermined interval in the direction perpendicular to the bridge axis. Placed in position. The second lower joint rebar 22L extends from the joining surface lower part 12L of the second joining end face 12B, and is arranged at a predetermined interval in the direction perpendicular to the bridge axis. The second upper joint rebar 22U extends from the joint surface upper part 12U of the second joint end surface 12B, and is the same in the direction perpendicular to the second lower joint rebar 22L at a predetermined interval in the direction perpendicular to the bridge axis. Placed in position.

  3 shows a III-III cross section in FIG. 2, and FIG. 4 shows a IV-IV cross section in FIG. As shown in FIGS. 2 to 4, the second joint rebar 22 is disposed at a position different from the first joint rebar 21 in the direction perpendicular to the bridge axis. More specifically, the second joint rebar 22 is disposed at the center of the first joint rebar 21 adjacent to each other in the direction perpendicular to the bridge axis. The first lower joint reinforcing bar 21L and the second lower joint reinforcing bar 22L have an extension length in which most of them overlap in the bridge axis direction. Further, the first upper joint reinforcing bar 21U and the second upper joint reinforcing bar 22U also have extension lengths in which most of each other overlap in the bridge axis direction.

  As shown in FIGS. 2 and 3, a plurality of through bars 25 are arranged below the first lower joint reinforcing bar 21 </ b> L and the second lower joint reinforcing bar 22 </ b> L with a predetermined interval in the bridge axis direction. . The lower thread 25 is disposed both inside the floor slab body 11 and inside the joint concrete 13. The lower reinforcing bar 25 extends in a direction perpendicular to the bridge axis, has a length extending over all the first lower joint reinforcing bars 21L and the second lower joint reinforcing bars 22L, and constitutes a distribution bar. In addition, the lower reinforcement | strengthening bar | burr 25 does not need to be comprised by the one reinforcing bar which has the said length, and may be comprised by the several reinforcing bar connected by the lap joint etc. FIG. In the present embodiment, three through bars 25 are arranged inside the joint concrete 13. The central lower reinforcing bar 25 is arranged in the center of the joint surface lower part 12L facing each other, and the two lower reinforcing bars 25 at both ends are in the overlapping portion of the first lower joint reinforcing bar 21L and the second lower joint reinforcing bar 22L. It is arranged in the vicinity of the fixing unit 23.

  As shown in FIGS. 2 and 4, a plurality of upper reinforcing bars 26 are arranged above the first upper joint reinforcing bar 21 </ b> U and the second upper joint reinforcing bar 22 </ b> U at a predetermined interval in the bridge axis direction. . The upper reinforcement 26 is disposed both inside the floor slab body 11 and inside the joint concrete 13. The upper reinforcing bar 26 extends in a direction perpendicular to the bridge axis, has a length extending over all the first upper joint reinforcing bars 21U and the second upper joint reinforcing bars 22U, and constitutes a distribution bar. The upper rebar 26 does not need to be configured by a single reinforcing bar having the above length, and may be configured by a plurality of reinforcing bars connected by a lap joint or the like. In the present embodiment, five upper reinforcing bars 26 are arranged inside the joint concrete 13. The central upper reinforcing bar 26 is disposed at the center of the upper joint surface 12U facing each other, and the two upper reinforcing bars 26 at both ends are formed at the overlapping portion of the first upper joint reinforcing bar 21U and the second upper joint reinforcing bar 22U. The remaining two upper reinforcing bars 26 are arranged in the vicinity of the fixing portion 23 in the overlapping portion of the first upper joint reinforcing bar 21U and the second upper joint reinforcing bar 22U.

  As shown in FIGS. 2 and 3, below the portion where the first lower joint reinforcing bar 21 </ b> L and the second lower joint reinforcing bar 22 </ b> L overlap with each other inside the joint concrete 13, the bridge shaft is offset at a position offset in the bridge shaft direction. A plurality of lower reinforcing bars 27 are arranged so as to extend in a perpendicular direction and to be continuous while overlapping in a direction perpendicular to the bridge axis. The lower reinforcing bars 27 are arranged in two rows so as to be continuous via the lower reinforcing bars 25 on both sides of the two lower reinforcing bars 25 arranged at both ends in the bridge axis direction inside the joint concrete 13. Has been. The lower reinforcing bar 27 has an inverted L shape when viewed in the direction perpendicular to the bridge axis.

  As shown in FIGS. 2 and 4, the bridge shaft is positioned above the portion where the first upper joint reinforcing bar 21 </ b> U and the second upper joint reinforcing bar 22 </ b> U overlap each other inside the joint concrete 13 at a position offset in the bridge shaft direction. A plurality of upper reinforcing bars 28 are disposed so as to extend in a perpendicular direction and to be continuous while overlapping in a direction perpendicular to the bridge axis. The upper reinforcing bars 28 are passed through on both sides in the bridge axial direction of the two upper reinforcing bars 26 arranged at both ends in the bridge axial direction of the portion where the first upper joint reinforcing bar 21U and the second upper joint reinforcing bar 22U overlap each other. They are arranged in two rows so as to be continuous via the line 26. The upper reinforcing bar 28 has an L shape when viewed in the direction perpendicular to the bridge axis.

  5A shows a VA-VA cross section in FIG. 2, FIG. 5B shows a VB-VB cross section in FIG. 2, and FIG. 5C shows FIGS. 5A and 5B. ). FIG. 6A shows a perspective view of the lower reinforcing bar 27, and FIG. 6B shows a perspective view of the upper reinforcing bar 28.

  As shown in FIGS. 5 and 6, the lower reinforcing bar 27 is formed by bending one reinforcing bar, and below the portion where the first lower joint reinforcing bar 21L and the second lower joint reinforcing bar 22L overlap each other. A lower restraint portion 27a extending in a direction perpendicular to the axis and a lower restraint portion 27a in cooperation with the lower restraint portion 27a so as to surround a plurality of first lower joint rebars 21L and second lower joint rebars 22L from three directions. A pair of first side restraint portions 27b extending upward from both ends of the first side, and a pair of first side restraints extending in the direction of the bridge axis in proximity to the first upper joint rebar 21U from the upper end of the first side portion restraint portion 27b And an extending portion 27c.

  The upper reinforcing bar 28 is formed by bending one reinforcing bar, and is an upper restraining portion 28a that extends in a direction perpendicular to the bridge axis above the overlapping portion of the first upper joint reinforcing bar 21U and the second upper joint reinforcing bar 22U. And a pair of first extending downward from both ends of the upper restraint portion 28a so as to surround the first upper joint rebar 21U and the second upper joint rebar 22U from three sides in cooperation with the upper restraint portion 28a. It has a two-side restraint portion 28b and a pair of second extension portions 28c that extend in the bridge axis direction in proximity to the second lower joint reinforcing bar 22L from the lower end of the second side-part restraint portion 28b.

  As shown in FIGS. 5A and 5B, the lower reinforcing bar 27 of the present embodiment includes four first lower joint reinforcing bars by a lower restraint portion 27a and a pair of first side restraint portions 27b. 21L and three second lower joint reinforcing bars 22L arranged between them are surrounded from below and from both sides. The 1st side part restraint part 27b is made into the length which arrange | positions the 1st extension part 27c to the side of the 1st upper joint reinforcement 21U. Accordingly, the lower reinforcing bars 27 also surround the four first upper joint reinforcing bars 21U and the three second upper joint reinforcing bars 22U arranged between them from the lower side and the three sides.

  Between the lower reinforcing bars 27 adjacent to each other in the direction perpendicular to the bridge axis, there is only one second lower joint reinforcing bar 22L as the lower joint reinforcing bars 21L and 22L not surrounded by the lower reinforcing bar 27, and the first lower reinforcing bar 22L. The joint rebar 21L does not exist. The single second lower joint reinforcing bar 22L is surrounded by a lower reinforcing bar 27 that is offset by the reinforcing bar diameter. That is, by providing the plurality of lower reinforcing bars 27 so as to be continuous while overlapping in the direction perpendicular to the bridge axis, all the lower joint reinforcing bars 21L, 22L and all the upper joint reinforcing bars 21U, 22U are the lower reinforcing bars. It is surrounded from 3 sides by 27.

  The plurality of lower reinforcing bars 27 are continuously arranged so as to overlap in this manner, so that a pair of continuously arranged lower reinforcing bars 27 (the lower reinforcing bar 27 in FIG. 5A and FIG. 5) are arranged. (B) The lower reinforcing bars 27) are composed of a plurality of (two first lower reinforcing bars 27) by the overlapping portion of the lower restraining portion 27a and the pair of first side restraining portions 27b provided at both ends thereof. Lower joint rebars 21L and 22L, a total of three joint rebars 21L and one second lower joint rebar 22L, and a plurality (two first upper joint rebars 21U and one second upper joint rebar 22U). 3) and the upper joint rebars 21U and 22U from three sides.

  The upper reinforcing bars 28 of the present embodiment include four second upper joint reinforcing bars 22U and three first upper bars arranged between the upper restricting portions 28a and the pair of second side portion restricting portions 28b. The joint rebar 21U is surrounded from above and from both sides. The 2nd side part restraining part 28b is made into the length which arrange | positions the 2nd extension part 28c to the side of the 2nd lower joint reinforcement 22L. Therefore, the upper reinforcing bar 28 surrounds the four second lower joint reinforcing bars 22L and the three first lower joint reinforcing bars 21L arranged between them from the upper and both sides.

  Between the upper reinforcing bars 28 adjacent to each other in the direction perpendicular to the bridge axis, only one first upper joint reinforcing bar 21U exists as the upper joint reinforcing bars 21U and 22U not surrounded by the upper reinforcing bars 28, and the second upper The joint rebar 22U does not exist. The first upper joint reinforcing bar 21U is surrounded by an upper reinforcing bar 28 that is offset by the reinforcing bar diameter. That is, since the plurality of upper reinforcing bars 28 are provided so as to be overlapped in the direction perpendicular to the bridge axis, all the upper joint reinforcing bars 21U and 22U are surrounded by the upper reinforcing bars 28 from three directions. .

  Since the plurality of upper reinforcing bars 28 are continuously arranged so as to overlap in this way, a pair of continuously arranged upper reinforcing bars 28 (the upper reinforcing bars 28 in FIG. 5A and FIG. 5). In (B), the upper reinforcing bars 28) are composed of a plurality of pieces (one first upper part) by an overlapping portion of the upper restraint portion 28a and a pair of second side restraint portions 28b provided at both ends thereof. Upper joint rebars 21U and 22U, a total of three joint rebars 21U and two second upper joint rebars 22U, and a plurality (one first lower joint rebar 21L and two second lower joint rebars 22L). The lower joint rebars 21L and 22L are surrounded from three directions.

  The lower reinforcing bar 27 and the upper reinforcing bar 28 cooperate with each other to thereby provide a plurality of first lower joint reinforcing bars 21L and second lower joint reinforcing bars 22L, and a plurality of first upper joint reinforcing bars 21U and second upper reinforcing bars. The joint rebar 22U is surrounded from four directions. Accordingly, all the joint reinforcing bars 21 and 22 are surrounded by the lower reinforcing bar 27 and the upper reinforcing bar 28 from four directions.

  Moreover, the overlapping part of a pair of continuously arranged lower reinforcing bars 27 (one in FIG. 5A and one in FIG. 5B) and a pair of continuously arranged upper reinforcing bars 28 are provided. The overlapping portions (one in FIG. 5A and one in FIG. 5B) are arranged at different positions in the direction perpendicular to the bridge axis. Accordingly, six joint reinforcing bars 21 (21U, 22U, 21L, 22L) surrounded by three overlapping portions of a pair of continuously disposed lower reinforcing bars 27 and a pair of continuously disposed upper reinforcing bars 28 are provided. The six joint reinforcing bars 21 (21U, 22U, 21L, 22L) surrounded by three overlapping portions are common to four, and the remaining two are different from each other.

  Next, with reference to FIG.7 and FIG.8, the construction method of the joint structure 10 of the PCa floor slab 8 is demonstrated.

  First, a plurality of PCa floor slabs 8 as shown in FIG. 7 are prepared. Prior to this, the lower reinforcing bar 25, the upper reinforcing bar 26, the lower reinforcing bar 27, and the upper reinforcing bar 28 of the above configuration are prepared in advance. This PCa floor slab 8 becomes the second PCa floor slab 8B when it is arranged at a predetermined position on the bridge girder 3. After the PCa floor slab 8 is arranged on the bridge girder 3, the next PCa floor slab 8 is placed on the bridge girder 3. When it is arranged at a predetermined position, it becomes the first PCa floor slab 8A. The PCa floor slab 8 includes a plurality of first upper joint reinforcing bars 21U and a plurality of first lower joint reinforcing bars 21L on the first joint end face 12A side on the right side in the figure, and on the second joint end face 12B side on the left side in the figure. A plurality of second upper joint reinforcing bars 22U and a plurality of second lower joint reinforcing bars 22L are provided.

  On the first joint reinforcing bar 21 side, three lower reinforcing bars 25 and two rows are arranged below the first lower joint reinforcing bar 21L (below the portion overlapping the second lower joint reinforcing bar 22L of the PCa floor slab 8 arranged in proximity). A lower reinforcing bar 27 is arranged in advance, and one upper reinforcing bar 26 is previously placed above the first upper joint reinforcing bar 21U (above the portion not overlapping with the second upper joint reinforcing bar 22U of the PCa floor slab 8 arranged in proximity). Arrange it. The lower reinforcing bars 27 may bind the lower restraining portion 27a to the first lower joint reinforcing bar 21L and bind the first extending portion 27c to the first upper joint reinforcing bar 21U.

  On the second joint reinforcing bar 22 side, four upper reinforcing bars 26 and two rows of upper reinforcing bars 28 are arranged in advance above the second upper joint reinforcing bar 22U. In the upper reinforcing bar 28, the upper restraining portion 28a may be bound to the second upper joint reinforcing bar 22U, and the second extending portion 28c may be bound to the second lower joint reinforcing bar 22L.

  Next, as shown in FIG. 8 (A), the PCa floor slab 8 thus arranged is arranged as a first PCa floor slab 8A at a predetermined position on the bridge girder 3 (FIG. 1). The PCa floor slab 8 is suspended as a second PCa floor slab 8B from above and placed at a predetermined position on the bridge girder 3 adjacent to the first PCa floor slab 8A. At this time, the reinforcing bars do not interfere with each other.

  By disposing the second PCa floor slab 8B at a predetermined position, as shown in FIG. 8B, the first joint end face 12A of the first PCa floor slab 8A and the second PCa floor slab 8B. A gap G is formed between the second joint end face 12B and the second upper joint rebar 22U of the second PCa floor slab 8B and the first upper joint rebar 21U of the first PCa floor slab 8A in the bridge axial direction. The second lower joint rebar 22L of the second PCa floor slab 8B overlaps the first lower joint rebar 21L of the first PCa floor slab 8A in the bridge axis direction.

  Further, the lower reinforcing bar 27 surrounds the four first lower joint reinforcing bars 21L and the three second lower joint reinforcing bars 22L from three directions by the lower restraining part 27a and the pair of first side restraining parts 27b. The upper reinforcing bars 28 are arranged so as to surround the three first upper joint reinforcing bars 21U and the four second upper joint reinforcing bars 22U from three directions by the upper restraining portion 28a and the pair of second side restraining portions 28b. Placed in. That is, the lower reinforcing bars 27 and the lower reinforcing bars 25 are previously bound to the first lower joint reinforcing bars 21L and arranged at predetermined positions, and the upper reinforcing bars 28 and the upper reinforcing bars 26 are previously connected to the second upper joint reinforcing bars 22U. By binding and arranging at a predetermined position, it is not necessary to perform the rebar assembling work after the first PCa floor slab 8A or the second PCa floor slab 8B is arranged at a predetermined position.

  Thereafter, the mold 31 is assembled under the gap G, and concrete is placed in the gap G and hardened as shown in FIG. 8C, whereby the first lower joint reinforcement 21L, the first lower joint reinforcement 21L, the 2nd upper joint reinforcing bar 22U, the 2nd lower joint reinforcing bar 22L, the lower reinforcing bar 27, and the joint concrete 13 in which the upper reinforcing bar 28 were wound are built. After the joint concrete 13 is hardened, the mold 31 is removed. Thereby, the joint structure 10 having the above-described configuration is constructed.

  Hereinafter, the joint structure 10 which concerns on embodiment, and the effect of the construction direction are demonstrated.

  As shown in FIGS. 3 and 4, the joint structure 10 includes a lower restraint portion 27a extending in a direction perpendicular to the bridge axis below a portion where the first lower joint reinforcing bar 21L and the second lower joint reinforcing bar 22L overlap each other, and In cooperation with the lower restraint portion 27a, a pair of first sides extending upward from both ends of the lower restraint portion 27a so as to surround the plurality of first lower joint rebars 21L and the second lower joint rebar 22L from three directions. It includes a plurality of lower reinforcing bars 27 that include a portion restraining portion 27b and are provided so as to be continuous while overlapping in a direction perpendicular to the bridge axis. Further, the joint structure 10 cooperates with the upper restraint portion 28a and the upper restraint portion 28a that extend in the direction perpendicular to the bridge axis above the portions of the first upper joint rebar 21U and the second upper joint rebar 22U that overlap each other. And a pair of second side restraint portions 28b extending downward from both ends of the upper restraint portion 28a so as to surround the plurality of first upper joint rebars 21U and the second upper joint rebar 22U from three directions, And a plurality of upper reinforcing bars 28 provided so as to be continuous while overlapping in a perpendicular direction.

  Accordingly, the lower joint reinforcing bars 21L and 22L are restrained by the lower reinforcing bars 27, the upper joint reinforcing bars 21U and 22 are restrained by the upper reinforcing bars 28, and the restraining force of the joint concrete 13 is increased. It is possible to suppress cracks in the concrete. In addition, the first PCa floor slab 8A is disposed in a state where the lower reinforcing bar 27 is assembled in advance to the first PCa floor slab 8A, and the upper reinforcing bar 28 is assembled in advance in the state where the upper reinforcing bar 28 is assembled to the second PCa floor slab 8B. Since the two PCa floor slabs 8B are arranged, it is possible to eliminate the amount of rebar assembly work on site. Furthermore, since the lower reinforcing bar 27 and the upper reinforcing bar 28 can be arranged at predetermined positions without necessarily recessing the first joint end face 12A and the second joint end face 12B, it is possible to reduce the amount of on-site concrete placement. It is.

  As shown in FIGS. 2 and 6, the lower reinforcing bar 27 includes a first upper joint reinforcing bar 21U from the upper end of the first side restraint portion 27b in addition to the lower restraint portion 27a and the pair of first side restraint portions 27b. And a pair of first extending portions 27c extending in the bridge axis direction. In addition to the upper restraint portion 28a and the pair of second side restraint portions 28b, the upper reinforcement bar 28 extends from the lower end of the second side restraint portion 28b in the vicinity of the second lower joint rebar 22L in the bridge axis direction. It further has a pair of second extending portions 28c that come out. Accordingly, the adhesion force of the first side restraint portion 27b and the second side restraint portion 28b to the joint concrete 13 is increased, and the restraint force of the lower joint rebars 21L and 22L by the lower reinforcement bar 27 and the upper reinforcement bar 28 are increased. Since the restraining force of the upper joint rebars 21U and 22U is increased, cracks in the concrete are effectively suppressed.

  As shown in FIG. 3 to FIG. 5, a pair of lower reinforcing bars 27 provided so as to be continuous are an overlapping portion of the lower restraint portion 27a and a pair of first side restraint portions provided at both ends thereof. 27b surrounds the plurality of lower joint reinforcing bars 21L and 22L and the plurality of upper joint reinforcing bars 21U and 22U from three directions. Further, a pair of upper reinforcing bars 28 provided so as to be continuous are formed by a plurality of lower joints by an overlapping portion of the upper restraining portion 28a and a pair of second side restraining portions 28b provided at both ends thereof. The reinforcing bars 21L and 22L and the plurality of upper joint reinforcing bars 21U and 22U are surrounded from three directions. As a result, a plurality of upper joint reinforcing bars 21U and 22U and a plurality of lower joint reinforcing bars 21L and 22L are not only one lower reinforcing bar 27 and upper reinforcing bar 28, but also by three overlapping parts. Therefore, the restraining force of the lower joint reinforcing bars 21L and 22L and the restraining force of the upper joint reinforcing bars 21U and 22U by the lower reinforcing bar 27 and the upper reinforcing bar 28 are increased.

  As shown in FIG. 5, the upper joint reinforcing bars 21U and 22U and the lower joint reinforcing bars 21L and 22L that the overlapping portions of the pair of lower reinforcing bars 27 provided continuously are surrounded from three sides are continuous. The upper joint reinforcing bars 21U and 22U and the lower joint reinforcing bars 21L and 22L surrounded by three overlapping portions of the provided upper reinforcing bars 28 are at least partially different. As a result, the group of joint reinforcing bars 21 and 22 surrounded by the lower reinforcing bar 27 from three directions and the group of joint reinforcing bars 21 and 22 surrounded by the upper reinforcing bar 28 from the three directions are dispersedly arranged. The restraining force for the joint reinforcing bars 21 and 22 and the joint concrete 13 by the upper reinforcing bars 28 is evenly increased.

  As shown in FIGS. 2 to 4, the plurality of lower reinforcing bars 27 are arranged in the bridge axis direction including the vicinity of the fixing portion 23 of the first lower joint reinforcing bar 21 </ b> L and the vicinity of the fixing portion 23 of the second lower joint reinforcing bar 22 </ b> L. A plurality of upper reinforcing bars 28 are arranged in a plurality of rows in the bridge axis direction including the vicinity of the fixing portion 23 of the first upper joint reinforcing bar 21U and the vicinity of the fixing portion 23 of the second upper joint reinforcing bar 22U. ing. This makes it possible to increase the overlap length between the first upper joint rebar 21U and the second upper joint rebar 22U and the overlap length between the first lower joint rebar 21L and the second lower joint rebar 22L. Adhesive force to the joint concrete 13 is ensured, and the restraining force of the lower reinforcing bar 27 and the upper reinforcing bar 28 is effectively increased.

  Further, the joint structure 10 extends in a direction perpendicular to the bridge axis below a portion where the first lower joint reinforcing bar 21L and the second lower joint reinforcing bar 22L overlap with each other, and the plurality of first lower joint reinforcing bars 21L and the plurality of second lower joint reinforcing bars 21L. Extending in the direction perpendicular to the bridge axis above the overlapping portion of the lower reinforcing bar 25 having a length over all of the joint reinforcing bars 22L and the first upper joint reinforcing bar 21U and the second upper joint reinforcing bar 22U, a plurality of first reinforcing bars The upper joint reinforcing bar 21U and the upper through-bar 26 having a length extending over all of the plurality of second upper joint reinforcing bars 22U are further provided. This improves the bending strength of the joint portion in the direction perpendicular to the bridge axis. Moreover, the restraining force with respect to the joint reinforcing bars 21 and 22 and the joint concrete 13 by the lower reinforcing bar 27 and the upper reinforcing bar 28 becomes uniform in the direction perpendicular to the bridge axis.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, the specific configuration, arrangement, quantity, angle, and the like of each member or part can be changed as appropriate without departing from the spirit of the present invention. On the other hand, not all the constituent elements shown in the above embodiment are necessarily essential, and can be appropriately selected.

8 PCa floor slab 8A 1st PCa floor slab 8B 2nd PCa floor slab 10 Joint structure 11 Floor slab body 12 Joint end face 12A 1st joint end face 12B 2nd joint end face 13 Joint concrete 21 1st joint reinforcement 21L First lower joint rebar 21U First upper joint rebar 22 Second joint rebar 22L Second lower joint rebar 22U Second upper joint rebar 23 Anchoring portion 25 Lower reinforcer 26 Upper reinforcer 27 Lower reinforcing bar 27a Lower restraint 27b First Side restraint portion 27c First extension portion 28 Upper reinforcement 28a Upper restraint portion 28b Second side restraint portion 28c Second extension portion G Gap

Claims (7)

The first PCa floor slabs are arranged at intervals in the bridge axis perpendicular direction so as to extend from the upper and lower portions of the first joint end surface extending in the direction perpendicular to the bridge axis, and each has a fixing portion at the tip. A plurality of first upper joint reinforcing bars and a plurality of first lower joint reinforcing bars;
Extending from the upper and lower portions of the second joint end face facing the first joint end face in the second PCa floor slab disposed close to the first PCa floor slab with a gap in the bridge axis direction And a plurality of extension lengths arranged at intervals in the direction perpendicular to the bridge axis, each having a fixing portion at the tip, and overlapping with the corresponding first upper joint rebar or the first lower joint rebar. A second upper joint reinforcing bar and a plurality of second lower joint reinforcing bars,
A lower constraining portion extending in a direction perpendicular to the bridge axis below a portion where the first lower joint rebar and the second lower joint rebar overlap each other, and a plurality of the first constraining bars in cooperation with the lower constraining portion. A pair of first side restraints extending upward from both ends of the lower restraint so as to surround the lower joint reinforcement and the second lower joint reinforcement from three directions, while overlapping in the direction perpendicular to the bridge axis A plurality of lower reinforcing bars provided to be continuous;
An upper restraint portion extending in a direction perpendicular to the bridge axis above the overlapping portion of the first upper joint rebar and the second upper joint rebar, and a plurality of the first restraint portions in cooperation with the upper restraint portion. Including a pair of second side restraint portions extending downward from both ends of the upper restraint portion so as to surround the upper joint rebar and the second upper joint rebar from three sides, while overlapping in the direction perpendicular to the bridge axis A plurality of upper reinforcing bars provided to be continuous;
The first upper joint rebar, the first lower joint rebar, the second upper joint rebar, the second lower joint rebar, the lower reinforcement bar and the joint concrete constructed in the gap so as to involve the upper reinforcement bar; A joint structure of a PCa floor slab characterized by comprising: The lower reinforcing bar further has a pair of first extending portions extending in the bridge axis direction in proximity to the first upper joint reinforcing bar from the upper end of the first side restraint portion,
The said upper reinforcement bar | burr further has a pair of 2nd extension part extended in the bridge axis direction in proximity to the said 2nd lower joint reinforcement from the lower end of the said 2nd side part restraint part. The joint structure of PCa floor slabs according to 1. A pair of lower reinforcing bars provided so as to be continuous are provided by the overlapping part of the lower restraining part and the pair of first side restraining parts provided at both ends of the overlapping part. The first lower joint reinforcing bar and the second lower joint reinforcing bar, and the plurality of first upper joint reinforcing bars and the second upper joint reinforcing bar are surrounded from three directions,
A pair of upper reinforcing bars provided so as to be continuous are provided by the overlapping part of the upper restraining part and the pair of second side restraining parts provided at both ends of the overlapping part. 3. The first upper joint reinforcing bar and the second upper joint reinforcing bar, and the plurality of first lower joint reinforcing bars and the second lower joint reinforcing bar are surrounded from three directions. The joint structure of the PCa floor slab described in 1. The first upper joint rebar and the first lower joint rebar are provided at positions corresponding to each other in the direction perpendicular to the bridge axis,
The second upper joint reinforcing bar and the second lower joint reinforcing bar are provided at positions corresponding to each other different from the first upper joint reinforcing bar and the first lower joint reinforcing bar in the direction perpendicular to the bridge axis,
The first upper joint reinforcing bar, the second upper joint reinforcing bar, the first lower joint reinforcing bar, and the second lower lower bar surrounding the overlapping portions of the pair of lower reinforcing bars provided continuously from three directions. The first upper joint rebar, the second upper joint rebar, the first lower joint rebar, and the joint rebar, and the overlapping portions of the pair of upper reinforcing bars provided in a continuous manner from three sides, The joint structure of a PCa floor slab according to claim 3, wherein the second lower joint reinforcing bar differs at least in part. The lower reinforcing bars are arranged in a plurality of rows in the bridge axis direction including the vicinity of the fixing part of the first lower joint reinforcing bar and the vicinity of the fixing part of the second lower joint reinforcing bar,
The upper reinforcing bars are arranged in a plurality of rows in a bridge axis direction including the vicinity of the fixing portion of the first upper joint reinforcing bar and the vicinity of the fixing portion of the second upper joint reinforcing bar. The joint structure for PCa floor slabs according to any one of claims 1 to 4. The first lower joint reinforcing bar and the second lower joint reinforcing bar extend in a direction perpendicular to the bridge axis below a portion where the first lower joint reinforcing bar and the second lower joint reinforcing bar overlap each other. Having a lower muscle,
The first upper joint reinforcing bar and the second upper joint reinforcing bar extend in the direction perpendicular to the bridge axis above the overlapping portion of the first upper joint reinforcing bar, and have a length over all of the first upper joint reinforcing bar and the second upper joint reinforcing bar. The joint structure for PCa floor slabs according to any one of claims 1 to 5, further comprising an upper reinforcing bar. A plurality of first upper joint reinforcing bars arranged at intervals in a direction perpendicular to the bridge axis so as to extend from an upper part and a lower part of a first joint end face extending in a direction perpendicular to the bridge axis, and having a fixing portion at each end; Preparing a first PCa floor slab comprising a plurality of first lower joint rebars;
A plurality of second upper joint reinforcing bars arranged at intervals in a direction perpendicular to the bridge axis so as to extend from an upper part and a lower part of a second joint end surface extending in a direction perpendicular to the bridge axis, and having a fixing portion at each end; Providing a second PCa floor slab comprising a plurality of second lower joint rebars;
Preparing a plurality of lower reinforcing bars including a lower restraint portion extending in a direction perpendicular to the bridge axis, and a pair of first side restraint portions extending upward from both ends of the lower restraint portion;
Preparing a plurality of upper reinforcing bars including an upper restraint portion extending in a direction perpendicular to the bridge axis, and a pair of second side restraint portions extending downward from both ends of the upper restraint portion;
Placing the first PCa floor slab in a predetermined position on the bridge beam;
A gap is formed between the second joint end surface and the first joint end surface, the second upper joint rebar overlaps with the first upper joint rebar, and the second lower joint rebar is the first lower joint rebar. Placing the second PCa floor slab on the bridge girder so as to overlap the joint reinforcing bar at a position close to the first PCa floor slab;
The lower restraint portion is located below the overlapping portion of the first lower joint reinforcement and the second lower joint reinforcement, and a plurality of the first restraint portions and the pair of first side restraint portions are used. Disposing the lower reinforcing bar so as to surround the first lower joint reinforcing bar and the second lower joint reinforcing bar from three directions;
The upper restraint portion is positioned above the overlapping portion of the first upper joint rebar and the second upper joint rebar, and a plurality of the first restraint portions and the pair of second side restraint portions are used. Disposing the upper reinforcing bar so as to surround the first upper joint bar and the second upper joint bar from three directions;
Constructing joint concrete in the gap so as to involve the first upper joint reinforcing bar, the first lower joint reinforcing bar, the second upper joint reinforcing bar, the second lower joint reinforcing bar, the lower reinforcing bar and the upper reinforcing bar. And
The step of placing the lower reinforcing bar is performed before the step of placing the first PCa floor slab;
The method for constructing a joint structure of PCa floor slabs, wherein the step of arranging the upper reinforcing bars is performed before the step of arranging the second PCa floor slab.

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