JP6489087B2 - Joint structure of precast concrete slab - Google Patents

Description

  The present invention relates to a joint structure of a precast concrete floor slab, and more specifically, the joint length can be made shorter than that of a lap joint structure, and the floor slab thickness can be made thinner than that of a loop reinforcing bar joint structure. The present invention relates to a joint structure of a precast concrete slab that can reduce the burden of bar arrangement work.

  One of the joint structures of precast concrete slabs is a lap joint structure. In the lap joint structure, it is generally necessary to secure a length of about 30 times the diameter of the reinforcing bar as the lap joint length. In the lap joint structure, the length of the joint portion tends to be long.

  As a joint structure of a precast concrete floor slab in which the length of the joint can be made shorter than the lap joint structure, there is a loop reinforcing bar joint structure 100 as shown in FIG. 20 (see, for example, Patent Document 1 (page 13, FIG. 16)). ). The loop rebar joint structure 100 is a joint structure that connects precast concrete floor slabs 102 adjacent to each other in the bridge axis direction in the bridge axis direction. The loop rebar joint structure 100 includes a loop rebar 104, a reinforcing reinforcing bar 106, and a space-filled concrete 108. It is configured. The reinforcing reinforcing bars 106 are reinforcing bars extending in a direction perpendicular to the bridge axis, and a part of the reinforcing reinforcing bars 106 is inserted and arranged inside the loop reinforcing bars 104 so as to be orthogonal to the loop reinforcing bars 104.

  However, in the loop reinforcing bar joint structure 100, since the reinforcing bar is bent to form the loop reinforcing bar 104, the minimum thickness of the floor slab is determined by the predetermined minimum bending radius of the reinforcing bar. For this reason, the floor slab using the loop reinforcing bar joint structure 100 tends to be thicker than in the case of the lap joint structure.

  Further, in the loop reinforcing bar joint structure 100, the reinforcing reinforcing bars 106 arranged in the loop reinforcing bars 104 so as to be orthogonal to the loop reinforcing bars 104 are installed from the direction perpendicular to the bridge axis after the precast concrete floor slab 102 is installed at a predetermined installation location. It is necessary to insert into the closed cross section where the loop reinforcing bars 104 overlap each other. For this reason, much labor is required for the bar arrangement work on site.

JP 2012-62664 A

  The present invention has been made in view of the above points, and can shorten the length of the joint portion as compared with the lap joint structure, and can reduce the floor slab thickness as compared with the loop reinforcing bar joint structure. It is an object of the present invention to provide a joint structure for a precast concrete slab that can reduce the burden of the bar arrangement work.

  This invention solves the said subject with the joint structure of the following precast concrete floor slabs.

  That is, the first aspect of the joint structure of the precast concrete floor slab according to the present invention is embedded in the joint end surface of the side end portion of the precast concrete floor slab with a space in the vertical direction from the joint end surface to the precast concrete. The upper and lower joint reinforcing bars arranged so as to protrude in a direction substantially parallel to the floor slab surface of the floor slab, and the joint end faces of the precast concrete floor slab arranged so that the joint end faces face each other A joint structure of precast concrete floor slabs for connecting the precast concrete floor slabs, wherein the joint end surfaces are arranged so as to face each other. The upper joint rebars of the precast concrete floor slabs arranged so that the end faces face each other are The lower joint rebars of the precast concrete slab, which are arranged at substantially the same height position with a predetermined interval and arranged so that the joint end faces face each other, are at substantially the same height position. Disposed at a predetermined interval, an upper-stage detent member is provided at the tip of the protruding upper joint rebar, and the upper-stage detent member is attached to the end of the projecting upper joint rebar. When viewed from the horizontal direction perpendicular to the longitudinal direction of the upper joint rebar to which the upper shaft is joined, the upper shaft joined so that the central axes of the upper joint are substantially coincident with each other, the direction opposite to the direction in which the upper joint rebar protrudes An upper locking portion having an upper inner surface extending obliquely downward in the direction on the side opposite to the direction in which the upper joint reinforcing bar protrudes, and the upper shaft portion and the upper locking portion are integrated. Been A lower-stage detent member is provided at each end of the projecting lower joint rebar, and the lower-stage detent members are arranged so that their central axes substantially coincide with the projecting end of the lower joint rebar. A lower inner surface that extends obliquely upward in a direction opposite to the direction in which the lower joint reinforcing bar protrudes when viewed from the horizontal direction orthogonal to the longitudinal direction of the lower joint reinforcing bar to which the lower lower joint is joined. A lower-stage locking portion on a side opposite to the direction in which the lower-stage joint reinforcing bar protrudes, and the lower-stage shaft portion and the lower-stage locking portion are integrated, and the upper-level joint is further integrated. An upper orthogonal reinforcing bar arranged adjacent to the lower part of the reinforcing bar and extending in a substantially horizontal direction substantially orthogonal to the longitudinal direction of the upper joint reinforcing bar is disposed between the upper locking portions, and Adjacent upward A lower orthogonal reinforcing bar extending in a substantially horizontal direction substantially orthogonal to the longitudinal direction of the lower joint reinforcing bar is disposed between the lower locking portions, and from the joint end surface of the precast concrete slab The projecting portion of the upper joint reinforcing bar, the site of the lower joint reinforcing rod projecting from the joint end surface of the precast concrete floor slab, the upper detent member, the lower detent member, the upper orthogonal rebar, and the lower step The periphery of the orthogonal reinforcing bar is a joint structure of a precast concrete slab characterized by being covered with the padding material.

  Here, in this application, the central axis of a member is a line formed by connecting the centroids of the respective sections of the member orthogonal to the longitudinal direction of the member.

  A central axis of the upper joint reinforcing bar of the upper inner surface of the upper locking portion of the upper shift preventing member joined to the upper joint reinforcing bar in a cut surface cut along a vertical plane including the central axis of the upper joint reinforcing bar The lower-stage engagement member of the lower-stage detent member joined to the lower-joint reinforcing bar at a cut surface cut by a vertical plane including the central axis of the lower-joint reinforcing bar is 45 ° to 85 °. It is preferable that the angle formed by the center axis of the lower joint reinforcing bar on the lower inner surface of the stop portion is 45 ° or more and 85 ° or less.

  According to the second aspect of the joint structure of the precast concrete floor slab according to the present invention, the precast concrete floor slab is embedded in the joint end surface of the side end portion of the precast concrete floor slab with a space therebetween in the vertical direction. Between the joint end surfaces of the precast concrete slabs arranged so that the joint end surfaces are opposed to the upper joint reinforcing bars and the lower joint reinforcing bars arranged so as to protrude in a direction substantially parallel to the floor plate surface of A joint structure of precast concrete floor slabs connecting the precast concrete floor slabs arranged so that the joint end faces face each other, wherein the joint end faces are The upper joint reinforcing bars of the precast concrete floor slabs arranged to face each other are substantially the same. The lower joint reinforcing bars of the precast concrete floor slabs are arranged at predetermined height positions at substantially the same height position. An upper-stage detent member is provided at the tip of the protruding upper joint reinforcing bar, and the upper-stage detent member is arranged at the center of each other at the end of the projecting upper joint rebar. The upper shaft portion joined so that the shafts substantially coincide with each other, and the upper orthogonal inner surface extending downward so as to be substantially orthogonal to the longitudinal direction of the upper joint rebar is on the side opposite to the protruding direction of the upper joint rebar. The upper shaft portion and the upper step locking portion are integrated, and a lower slip prevention member is provided at the tip of the projecting lower joint reinforcing bar. The lower-stage detent member includes a lower-stage shaft portion joined so that the central axes of the lower-stage joint reinforcing bars substantially coincide with each other, and an upper portion so as to be substantially orthogonal to the longitudinal direction of the lower-stage joint reinforcing bars. A lower locking portion having a lower orthogonal inner surface extending on the side opposite to the direction in which the lower joint reinforcing bar protrudes, and the lower shaft portion and the lower locking portion are integrated. Furthermore, an upper orthogonal reinforcing bar that is arranged adjacent to the lower part of the upper joint reinforcing bar and extends in a substantially horizontal direction substantially orthogonal to the longitudinal direction of the upper joint reinforcing bar is arranged between the upper locking portions. A lower orthogonal reinforcing bar that is disposed adjacent to and above the lower joint reinforcing bar and extends in a substantially horizontal direction substantially orthogonal to the longitudinal direction of the lower joint reinforcing bar is disposed between the lower locking portions, Precast con A portion of the upper joint reinforcing bar protruding from the joint end face of the cleat floor slab, a portion of the lower joint reinforcing bar projecting from the joint end face of the precast concrete floor slab, the upper stage stopper member, the lower stage stopper member, The periphery of the upper orthogonal reinforcing bar and the lower orthogonal reinforcing bar is a joint structure of a precast concrete floor slab characterized by being covered with the padding material.

  The upper slip prevention member does not have a portion positioned above the upper edge of the upper joint rebar to which it is joined, and the lower slip restraining member has the part of the lower joint rebar to which it is joined. It is preferable that there is no part located below the lower edge.

  Here, when the upper joint rebar is a deformed bar, the upper edge of the upper joint rebar is the upper edge considered including the convex part provided on the surface, and when the lower joint rebar is a deformed rebar, the lower joint The lower edge of a reinforcing bar is the lower edge considered including the convex part provided in the surface.

  The shape of the upper stage locking part and the lower stage locking part may be a plate shape, for example.

  The upper-stage locking portion of the upper-stage detent member is arranged in a horizontal direction perpendicular to the longitudinal direction of the upper-stage joint reinforcing bar to which the upper-stage detent member is joined, on the side in the direction in which the upper-stage joint rebar is joined. As viewed from the direction, it has an upper outer surface that extends obliquely downward in the direction in which the upper joint reinforcing bar protrudes, and the lower locking portion of the lower locking member is a lower stage to which the lower locking member is joined. A lower outer surface extending obliquely upward in a direction in which the lower joint reinforcing bar protrudes when viewed from a horizontal direction orthogonal to the longitudinal direction of the lower joint reinforcing bar to which the lower reinforcing bar is joined, on the side in which the joint reinforcing bar protrudes. Preferably it is.

  It is preferable that the upper stage stopper member is integrally formed of cast iron or cast steel, and the lower stage stopper member is integrally formed of cast iron or cast steel.

  The upper shaft portion of the upper shift prevention member may be joined to the tip of the protruding upper joint rebar by flash welding, and the lower shaft portion of the lower shift member protrudes from the protruding lower joint rebar. The tip may be joined by flash welding.

  According to the joint structure of the precast concrete floor slab according to the present invention, the length of the joint can be made shorter than that of the lap joint structure, the floor slab thickness can be made thinner than that of the loop reinforcing bar joint structure, and further the distribution on site. The burden of muscle work can also be reduced.

The perspective view which looked at the joint structure 10 of the precast concrete floor slab which concerns on 1st Embodiment of this invention from diagonally upward 1 is a perspective view drawn from FIG. 1 excluding the upper orthogonal reinforcing bar 20 and the lower orthogonal reinforcing bar 22. Side view of the joint structure 10 viewed from a direction perpendicular to the bridge axis In the joint structure 10, a vertical cross-sectional view schematically showing a cross section obtained by cutting the distal end portion of the upper joint rebar 12 and the upper slip prevention member 16 with a vertical plane passing through the central axis 12 </ b> A of the upper joint rebar 12. In the joint structure 10, a front view of the upper shift preventing member 16 as viewed from the longitudinal direction of the upper shaft portion 16 </ b> A. In the joint structure 10, a vertical cross-sectional view schematically showing a cross section obtained by cutting the distal end portion of the lower joint rebar 14 and the lower slip stopper 18 with a vertical plane passing through the central axis 14 </ b> A of the lower joint rebar 14. In the joint structure 10, a front view of the lower slip prevention member 18 as viewed from the longitudinal direction of the lower shaft portion 18 </ b> A. Side view of the joint structure 10 as viewed from the direction perpendicular to the bridge axis schematically showing the state before the upper orthogonal reinforcing bars 20 and the lower orthogonal reinforcing bars 22 are arranged on site. Vertical sectional view schematically showing a first modified example (upper locking portion 26B of the upper locking member 26) of the upper locking portion 16B of the upper locking member 16 of the joint structure 10. A vertical sectional view schematically showing a first modification of the lower locking portion 18B of the lower slip stopper 18 of the joint structure 10 (the lower locking portion 28B of the lower slip stopper 28). Front view (upper stage deviation) showing a specific example ((a) upper stage locking part 30A, (b) upper stage locking part 30B) of a second modification of the upper stage locking part 16B of the upper stage locking member 16 of the joint structure 10. Front view seen from the longitudinal direction of the upper shaft portion 16A of the stopper member 16) Specific examples of the second modified example of the upper locking portion 16B of the upper shift preventing member 16 of the joint structure 10 ((a) upper locking portion 32A, (b) upper locking portion 32B, (c) upper locking portion 32C) (a front view as seen from the longitudinal direction of the upper shaft portion 16A of the upper slip prevention member 16) Front view (upper stage deviation) showing a specific example ((a) upper stage latching part 34A, (b) upper stage latching part 34B) of the upper stage latching part 16B of the upper stage latching member 16 of the joint structure 10 Front view seen from the longitudinal direction of the upper shaft portion 16A of the stopper member 16) Front view (upper stage deviation) showing a specific example ((a) upper stage locking part 36A, (b) upper stage locking part 36B) of the second stage locking part 16B of the upper stage locking part 16B of the joint structure 10 Front view seen from the longitudinal direction of the upper shaft portion 16A of the stopper member 16) The perspective view which looked at the joint structure 40 of the precast concrete floor slab which concerns on 2nd Embodiment of this invention from diagonally upward FIG. 15 is a perspective view drawn by removing the upper orthogonal reinforcing bar 20 and the lower orthogonal reinforcing bar 22 from FIG. Side view of the joint structure 40 viewed from the direction perpendicular to the bridge axis In the joint structure 40, a vertical cross-sectional view schematically showing a cross section obtained by cutting the distal end portion of the upper joint rebar 12 and the upper shift preventing member 42 with a vertical plane passing through the central axis 12 </ b> A of the upper joint rebar 12. In the joint structure 40, a vertical cross-sectional view schematically showing a cross section obtained by cutting the tip end portion of the lower joint rebar 14 and the lower slip stopper 44 on a vertical plane passing through the central axis 14 </ b> A of the lower joint rebar 14. Longitudinal side view of a conventional connecting structure between floor slabs using the loop reinforcing bar joint structure 100 as viewed from the direction perpendicular to the bridge axis

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view of a joint structure 10 of a precast concrete slab according to a first embodiment of the present invention as viewed obliquely from above, and FIG. 2 excludes the upper and lower orthogonal reinforcing bars 20 and 22 from FIG. FIG. 3 is a side view of the joint structure 10 of the precast concrete floor slab according to the first embodiment of the present invention as viewed from the direction perpendicular to the bridge axis. However, for the sake of illustration, the interstitial concrete 24 is not drawn in FIGS. 1 and 2. In FIG. 3, members inside the interstitial concrete 24 are also drawn with solid lines.

  A joint structure 10 of a precast concrete floor slab according to the first embodiment of the present invention (hereinafter sometimes simply referred to as “joint structure 10”) is a precast concrete floor slab arranged adjacent to each other in the bridge axis direction. 50 is a joint structure that connects the two, and the upper joint rebar 12 and the lower joint rebar 14, the upper slip prevention member 16 provided at the tip of the upper joint rebar 12, and the lower slip provided at the tip of the lower joint rebar 14. The stopper member 18, the upper orthogonal reinforcing bar 20 and the lower orthogonal reinforcing bar 22, and the interstitial concrete 24 are configured.

  The precast concrete floor slabs 50 arranged adjacent to each other in the bridge axis direction are arranged so that the joint end surfaces 52 of the side ends face each other, and the interstitial concrete 24 is filled between the joint end surfaces 52 facing each other. The upper joint rebar 12 projecting from the joint end surface 52 of the precast concrete floor slab 50, the lower joint rebar 14 projecting from the joint end surface 52 of the precast concrete floor slab 50, the upper slip prevention member 16, The periphery of the lower slip prevention member 18, the upper orthogonal reinforcing bar 20, and the lower orthogonal reinforcing bar 22 is covered with interstitial concrete 24.

  The upper joint rebar 12 and the lower joint rebar 14 protrude from the joint end surface 52 at the side end portion of the precast concrete floor slab 50 substantially in the direction of the bridge axis (in a direction substantially parallel to the floor slab surface of the precast concrete floor slab 50). The upper joint rebar 12 and the lower joint rebar 14 are arranged in a substantially vertical direction with an interval (for example, 100 mm) vertically. Further, the upper joint rebar 12 and the lower joint rebar 14 are deformed reinforcing bars having irregularities on the surface.

  The upper joint reinforcing bars 12 of the precast concrete floor slabs 50 arranged adjacent to each other so that the joining end faces 52 face each other are arranged at substantially the same height, and arranged at a predetermined interval (for example, 250 mm). Has been.

  Further, the lower joint reinforcing bars 14 of the precast concrete floor slabs 50 arranged adjacent to each other so that the joint end faces 52 face each other are arranged at substantially the same height position, and have a predetermined interval (for example, 250 mm). Is arranged in.

  An upper slip prevention member 16 is provided at the tip of the upper joint rebar 12. FIG. 4 is a vertical cross-sectional view schematically showing a cross section obtained by cutting the distal end portion of the upper joint rebar 12 and the upper shift preventing member 16 along a vertical plane passing through the central axis 12A of the upper joint rebar 12.

  As shown in FIG. 4, the upper slip prevention member 16 includes an upper shaft portion 16A and an upper step locking portion 16B. The upper stage shaft portion 16A and the upper stage locking portion 16B are integrated.

  The upper shaft portion 16A has an outer diameter that is substantially the same as the outer diameter of the upper joint rebar 12 (the outer diameter of the recess), so that the central axes of the upper joint portions 16A substantially coincide with the tips of the protruding upper joint rebar 12. It is joined to. This joining can be performed using flash welding, for example. The joint obtained by flash welding has a slightly larger diameter than before the joining, but the joint obtained by flash welding can be obtained by suppressing the diameter to the extent of the convex portion of the upper joint rebar 12 or less. A cover equivalent to 12 can be secured.

  When viewed from the horizontal direction (perpendicular to the bridge axis) perpendicular to the longitudinal direction of the upper joint rebar 12, the upper stage latching portion 16 </ b> B is provided with an upper joint reinforcing bar provided with the upper stage detent member 16 having the upper stage retaining portion 16 </ b> B. 12 has an upper inner surface 16B1 extending obliquely downward in a direction opposite to the direction in which the upper joint rebar 12 protrudes, on the side opposite to the direction in which the upper joint rebar 12 protrudes.

  The upper slip prevention member 16 includes the upper inner surface 16B1 so that the upper inner surface 16B1 serves as a bearing resistance surface and prevents the upper joint rebar 12 from being pulled out from the interstitial concrete 24. Further, since the upper inner surface 16B1 is a surface extending obliquely downward in a direction opposite to the direction in which the upper joint reinforcing bar 12 provided with the upper shift preventing member 16 having the upper locking portion 16B is provided, the interstitial concrete 24, the joint strength of the precast concrete slab 50 is further improved, and the upper joint rebar 12 is effectively resisted from protruding.

  Further, the upper inner surface 16B1 of the upper stage locking portion 16B and the side opposite to the upper stage inner surface 16B1 (the side in the direction in which the upper joint reinforcing bar 12 provided with the upper stage shift preventing member 16 having the upper stage locking portion 16B is protruded). Is substantially parallel to the upper outer surface 16B2, and the shape of the upper locking portion 16B is plate-shaped.

  In the cut surface obtained by cutting along a vertical plane including the central axis 12A of the upper joint rebar 12, the upper stage of the upper inner surface 16B1 of the upper stage locking portion 16B joined to the upper joint rebar 12 The angle α formed with the central axis 12A of the joint rebar 12 can effectively resist the protrusion of the upper joint rebar 12 in terms of securing a bearing resistance resistance point, effectively locking to the interstitial concrete 24, and the like. It is preferable that it is 45 degrees or more and 85 degrees or less at a point.

  Here, in the cut surface obtained by cutting along the vertical plane including the central axis 12A of the upper joint rebar 12, the angle formed by the central axis 12A of the upper joint rebar 12 of the upper inner surface 16B1 of the upper locking portion 16B is as shown in FIG. This means an angle α of 4.

  FIG. 5 is a front view of the upper slip prevention member 16 as viewed from the longitudinal direction of the upper shaft portion 16A. As shown in FIG. 5, the shape of the upper locking portion 16B (the shape seen from the longitudinal direction of the upper shaft portion 16A) is a substantially square shape, and the length of one side is about 30 mm to 40 mm. By setting the length of one side of the substantially square upper locking portion 16B to about 30 mm to 40 mm, it is possible to secure a bearing resistance resistance surface for locking to the interstitial concrete 24 and to form the interstitial concrete. The filling property when filling 24 can also be improved.

  Further, as shown in FIG. 5, the upper locking portion 16B does not have a portion positioned above the upper edge of the upper shaft portion 16A, and does not have a portion positioned higher than the upper edge of the upper joint rebar 12. For this reason, it has a joint structure that is advantageous in securing a concrete cover.

  The material of the upper slip prevention member 16 is not particularly limited as long as necessary performance (such as a locking effect on the interstitial concrete 24) can be obtained. For example, a member obtained by molding the upper slip prevention member 16 with cast iron or cast steel. It is good. When the upper stage stopper member 16 is a member formed of cast iron or cast steel, the upper stage stopper member 16 can be realized even if the shape of the upper stage stopper member 16 is somewhat complicated. The upper stage so as not to be positioned above the upper edge of the upper joint rebar 12 provided with the upper slip prevention member 16 (the upper edge considered including the convex part provided on the surface of the upper joint rebar 12). The anti-slip member 16 can be easily configured. It is advantageous in securing the concrete cover by preventing each part of the upper slip prevention member 16 from being positioned above the upper edge of the upper joint rebar 12 provided with the upper slip prevention member 16. It becomes a joint structure.

  A lower-stage slip prevention member 18 is provided at the tip of the lower-stage joint reinforcing bar 14. FIG. 6 is a vertical cross-sectional view schematically showing a cross section obtained by cutting the distal end portion of the lower joint rebar 14 and the lower slip stopper 18 along a vertical plane passing through the central axis 14A of the lower joint rebar 14.

  As shown in FIG. 6, the lower-stage slip prevention member 18 includes a lower-stage shaft portion 18A and a lower-stage locking portion 18B. The lower-stage shaft portion 18A and the lower-stage locking portion 18B are integrated.

  The lower shaft portion 18A has an outer diameter that is substantially the same as the outer diameter of the lower joint rebar 14 (the outer diameter of the recess), so that the center axes of the lower joint portions 14A substantially coincide with the tip of the protruding lower joint rebar 14. It is joined to. This joining can be performed using flash welding, for example. The joint obtained by flash welding has a slightly larger diameter than before the joining, but the joint obtained by flash welding has a lower joint rebar by suppressing it to about the diameter of the convex portion of the lower joint rebar 14. A cover equivalent to 14 can be secured.

  The lower locking portion 18B is viewed from the horizontal direction (the direction perpendicular to the bridge axis) perpendicular to the longitudinal direction of the lower joint rebar 14 and is provided with a lower shift stopper 18 having the lower locking portion 18B. 14 has a lower inner surface 18B1 that extends obliquely upward in a direction opposite to the direction in which 14 protrudes, on the side opposite to the direction in which the lower joint rebar 14 protrudes.

  The lower-stage slip prevention member 18 includes the lower-stage inner surface 18B1, thereby preventing the lower-stage inner face 18B1 from being a bearing resistance surface and preventing the lower-stage joint rebar 14 from being pulled out from the interstitial concrete 24. Further, the lower inner surface 18B1 is a surface extending obliquely upward in a direction opposite to the direction in which the lower joint reinforcing bar 14 provided with the lower shift preventing member 18 having the lower locking portion 18B is provided. 24, the joint strength of the precast concrete slab 50 is further improved, and the lower joint rebar 14 is effectively resisted from protruding.

  Further, the lower inner surface 18B1 of the lower locking portion 18B and the side opposite to the lower inner surface 18B1 (the side in the direction in which the lower joint reinforcing bar 14 provided with the lower slip prevention member 18 having the lower locking portion 18B protrudes). The lower step outer surface 18B2 is substantially parallel to the lower step locking portion 18B.

  In the cut surface obtained by cutting along the vertical plane including the central axis 14A of the lower joint reinforcing bar 14, the lower stage of the lower inner surface 18B1 of the lower stage locking portion 18B of the lower stage locking member 18 joined to the lower joint reinforcing bar 14 The angle β formed by the central axis 14A of the joint rebar 14 can effectively resist the protrusion of the lower joint rebar 14 in terms of securing a bearing resistance resistance point, effectively locking to the interstitial concrete 24, and the like. It is preferable that it is 45 degrees or more and 85 degrees or less at a point.

  Here, in the cut surface obtained by cutting along the vertical plane including the central axis 14A of the lower joint reinforcing bar 14, the angle formed by the central axis 14A of the lower joint reinforcing bar 14 of the lower inner surface 18B1 of the lower locking portion 18B is as shown in FIG. This means an angle β of 6.

  FIG. 7 is a front view of the lower slip prevention member 18 as viewed from the longitudinal direction of the lower shaft portion 18A. As shown in FIG. 7, the shape of the lower locking portion 18B (the shape seen from the longitudinal direction of the lower shaft portion 18A) is a substantially square shape, and the length of one side is about 30 mm to 40 mm. By setting the length of one side of the substantially square lower-stage locking portion 18B to about 30 mm to 40 mm, it is possible to secure a bearing resistance resistance surface for locking to the space-filled concrete 24, and space-filled concrete. The filling property when filling 24 can also be improved.

  Further, as shown in FIG. 7, the lower locking portion 18B has no part positioned below the lower edge of the lower shaft part 18A, and does not have a part positioned below the lower edge of the lower joint rebar 14. For this reason, it has a joint structure that is advantageous in securing a concrete cover.

  The material of the lower slip prevention member 18 is not particularly limited as long as necessary performance (such as a locking effect on the interstitial concrete 24) can be obtained. For example, a member obtained by molding the lower slip prevention member 18 with cast iron or cast steel. It is good. When the lower stage stopper member 18 is a member formed of cast iron or cast steel, the lower stage stopper member 18 can be realized even if the shape of the lower stage stopper member 18 is somewhat complicated. The lower stage so as not to be positioned below the lower edge of the lower joint rebar 14 provided with the lower slip prevention member 18 (the lower edge considered including the convex part provided on the surface of the lower joint rebar 14). The anti-slip member 18 can be easily configured. It is advantageous in securing the concrete cover by preventing each part of the lower slip prevention member 18 from being positioned below the lower edge of the lower joint rebar 14 at which the lower slip prevention member 18 is provided. It becomes a joint structure.

  Moreover, in the joint structure 10 of the precast concrete floor slab according to the first embodiment, the precast concrete floor slab joint structure 10 is arranged adjacent to the lower part of the upper joint rebar 12 and extends in a substantially horizontal direction substantially orthogonal to the longitudinal direction of the upper joint rebar 12. The upper orthogonal reinforcing bar 20 is disposed between the upper locking portions 16B, and is disposed adjacent to the upper portion of the lower joint reinforcing bar 14 in a substantially horizontal direction substantially orthogonal to the longitudinal direction of the lower joint reinforcing bar 14. The extending lower orthogonal reinforcing bars 22 are disposed between the lower locking portions 18B.

  By arranging the upper orthogonal reinforcing bars 20 and the lower orthogonal reinforcing bars 22 in this way, the joint structure 10 of the precast concrete floor slab according to the first embodiment can ensure the same yield strength as the parts other than the joint portions. it can.

  In order to arrange the upper orthogonal reinforcing bars 20 and the lower orthogonal reinforcing bars 22 in the field, as shown in FIG. 8, the upper orthogonal reinforcing bars 20 and the lower orthogonal reinforcing bars 22 corresponding to the number required for the upper joint reinforcing bars 12 are respectively made of wire 23 or the like. After attaching the precast concrete floor slab 50 at a predetermined position, the wire 23 such as the wire 23 used for the attachment is removed, and the upper and lower orthogonal reinforcing bars 20 and 22 are arranged at predetermined positions. . For this reason, it is not necessary to insert reinforcing bars in the direction perpendicular to the bridge axis at the site, and the work of arranging the upper and lower orthogonal reinforcing bars 20 and 22 is easy.

  On the other hand, when the conventional loop rebar joint structure is used, it is necessary to insert the rebar in the direction perpendicular to the bridge axis inside the closed section where the loop rebars overlap each other when viewed from the direction perpendicular to the bridge axis. It took time and effort to arrange the upper and lower orthogonal reinforcing bars.

(Effect of 1st Embodiment)
The joint structure 10 of the precast concrete floor slab according to the first embodiment of the present invention includes an upper shift prevention member 16 provided at the tip of the upper joint rebar 12 and a lower slip prevention member provided at the tip of the lower joint rebar 14. 18 and the upper locking portion 16B of the upper locking member 16 is opposite to the direction in which the upper joint reinforcing bar 12 provided with the upper locking member 16 having the upper locking portion 16B is projected. The lower joint member 18B has an upper inner surface 16B1 extending obliquely downward in the direction of the lower joint, and the lower stopper member 18B of the lower stopper member 18 is provided with a lower stopper member 18 having a lower stopper member 18B. Has a lower inner surface 18B1 extending obliquely upward in a direction opposite to the direction in which the protrusion protrudes.

  As described above, the upper inner surface 16B1 and the lower inner surface 18B1 are disposed obliquely with respect to the upper joint reinforcing bar 12 and the lower joint reinforcing bar 14 so as to be effectively locked to the interstitial concrete 24. The joint structure 10 of the precast concrete floor slab according to the embodiment has a large joint strength, and therefore, the length of the joint portion can be made shorter than that of the conventional lap joint structure.

  Moreover, in the joint structure 10 of the precast concrete floor slab according to the first embodiment of the present invention, since it is not necessary to process the reinforcing bar into a loop shape, the floor slab thickness can be made thinner than the conventional loop reinforcing bar joint structure. it can.

  Furthermore, in the joint structure 10 of the precast concrete floor slab according to the first embodiment of the present invention, there is no closed cross section as in the conventional loop reinforcing bar joint structure when viewed from the direction perpendicular to the bridge axis, and the joint structure 10 is arranged in the direction perpendicular to the bridge axis. It is not necessary to insert reinforcing bars into the joint from the direction perpendicular to the bridge axis, and the burden of the bar arrangement work on site can be reduced.

  In the joint structure 10 according to the first embodiment, the interstitial concrete 24 is used as the interstitial material for filling the space between the opposing joint end surfaces 52. However, the joint structure 10 protrudes from the joint end surface 52 of the precast concrete floor slab 50. The upper joint rebar 12, the lower joint rebar 14 projecting from the joint end surface 52 of the precast concrete slab 50, the upper slip prevention member 16, the lower slip prevention member 18, the upper orthogonal reinforcement 20, and the lower orthogonal reinforcement 22 As long as these members can be sufficiently integrated, it is possible to use a material other than concrete as a filling material for filling the space between the opposing joint end faces 52, and satisfy the required performance. If present, for example, mortar, resin mortar, or the like can be used instead of the interstitial concrete 24.

(First modification of the first embodiment)
In the joint structure 10 of the precast concrete floor slab according to the first embodiment of the present invention, the upper inner surface 16B1 and the upper outer surface 16B2 of the upper locking portion 16B are substantially parallel, and the shape of the upper locking portion 16B is a plate shape. Further, the lower inner surface 18B1 and the lower outer surface 18B2 of the lower locking portion 18B are substantially parallel, and the shape of the lower locking portion 18B is plate-like, but in the first embodiment, The shapes of the upper latching portion of the upper slip prevention member and the lower latch portion of the lower slip prevention member are not limited to a plate shape. A surface extending obliquely downward, similar to the upper inner surface 16B1 of the upper locking portion 16B (obliquely inclined in a direction opposite to the direction in which the upper joint rebar 12 provided with the upper shift preventing member 16 having the upper locking portion 16B is projected. As long as a surface extending downward is provided, the shape of the upper locking portion may be other than a plate shape. Further, a surface extending obliquely upward, similar to the lower inner surface 18B1 of the lower locking portion 18B (the direction opposite to the direction in which the lower joint rebar 14 provided with the lower slip prevention member 18 having the lower locking portion 18B protrudes) 2), the lower locking portion may have a shape other than a plate shape.

  FIG. 9 is a vertical cross-sectional view schematically showing a first modification of the upper locking portion 16B of the upper shift preventing member 16 of the joint structure 10 according to the first embodiment (upper locking portion 26B of the upper shift preventing member 26). FIG. 10 is a vertical cross-sectional view schematically showing a cross section obtained by cutting the distal end portion of the upper joint rebar 12 and the upper slip stopper 26 with a vertical plane passing through the central axis of the upper joint rebar 12, and FIG. 1 is a vertical sectional view (lower joint) schematically showing a first modification of the lower locking portion 18B of the lower locking member 18 of the joint structure 10 according to the first embodiment (the lower locking portion 28B of the lower locking member 28). FIG. 6 is a vertical cross-sectional view schematically showing a cross section obtained by cutting the distal end portion of the reinforcing bar 14 and the lower-stage deviation preventing member 28 along a vertical plane passing through the central axis of the lower-stage joint reinforcing bar 14.

  As shown in FIG. 9, the upper locking portion 26 </ b> B of the upper shift stopper 26, which is a first modification of the upper shift stopper 16, is a cross section obtained by cutting along a vertical plane passing through the central axis of the upper joint rebar 12. The upper locking portion 26B is provided with an upper inner surface 26B1 (an upper shift preventing member 26 having an upper locking portion 26B) extending obliquely downward, similar to the upper inner surface 16B1 of the upper locking portion 16B. The surface extending obliquely downward in the direction opposite to the direction in which the upper joint rebar 12 protrudes is defined as the direction in which the upper joint rebar 12 in which the upper slip prevention member 26 having the upper stage locking portion 26B is provided projects. Although it is on the opposite side, the upper outer surface 26B2 on the opposite side to the upper inner surface 26B1 (the side in the direction in which the upper joint rebar 12 on which the upper shift stopper member 26 having the upper locking portion 26B is provided) protrudes, Upper coupling reinforcing bars 12 upper displacement preventing member 26 having a stepped locking portion 26B is provided is in a plane extending obliquely downwardly in the direction to protrude. For this reason, the upper outer surface 26B2 receives a resistance force from the interstitial concrete 24 when the upper joint rebar 12 tries to protrude upward. Therefore, by using the upper shift stopper 26 having the upper locking portion 26B instead of the upper shift stopper 16 having the upper locking portion 16B, the upper joint rebar 12 can be prevented from protruding upward. Can do.

  Further, as shown in FIG. 10, the lower stage locking portion 28 </ b> B which is a first modification of the lower stage locking member 18 is obtained by cutting along a vertical plane passing through the central axis of the lower joint rebar 14. The shape of the cross section is trapezoidal, and the lower locking portion 28B is provided with a lower inner surface 28B1 (lower lower locking member 28 having a lower locking portion 28B) that extends obliquely upward like the lower inner surface 18B1 of the lower locking portion 18B. The direction in which the lower joint rebar 14 provided with the lower-stage detent member 28 having the lower-stage locking portion 28B protrudes on the surface extending obliquely upward in the direction opposite to the direction in which the lower joint rebar 14 protrudes. The lower outer surface 28 on the opposite side to the lower inner surface 28B1 (the side in the direction in which the lower joint rebar 14 in which the lower slip prevention member 28 having the lower locking portion 28B is provided) protrudes. 2 has a surface extending in a direction lower joint reinforcement 14 lower displacement preventing member 28 having a lower locking portion 28B is provided to project obliquely upward. For this reason, when the lower joint rebar 14 is about to protrude downward, the lower outer surface 28 </ b> B <b> 2 receives a resistance force from the interstitial concrete 24. Therefore, by using the lower shift preventing member 28 having the lower locking portion 28B instead of the lower shift preventing member 18 having the lower locking portion 18B, the lower joint rebar 14 is less likely to protrude downward. Can do.

  In FIG. 9, reference numeral 26 </ b> A is an upper stage shaft part similar to the upper stage shaft part 16 </ b> A, and in FIG. 10, reference numeral 28 </ b> A is a lower stage shaft part similar to the lower stage shaft part 18 </ b> A.

(Second modification of the first embodiment)
In the first modification of the first embodiment, the vertical sectional shape of the upper locking portion 26B of the upper shift preventing member 26 (the cross-sectional shape obtained by cutting along the vertical plane passing through the central axis of the upper joint rebar 12) and the lower The upper stage deviation of the first embodiment is that the vertical cross-sectional shape (the cross-sectional shape obtained by cutting along the vertical plane passing through the central axis of the lower joint joint 14) of the lower stage locking portion 28B of the deviation prevention member 28 is a trapezoid. Although the shape of the upper locking portion 16B of the locking member 16 and the shape of the lower locking portion 18B of the lower shifting member 18 are different, in the second modification of the first embodiment, the upper locking portion of the upper locking member is The shape seen from the front (from the longitudinal direction of the upper shaft portion of the upper slip prevention member) and the shape seen from the front (from the longitudinal direction of the lower shaft portion of the lower slip prevention member) of the lower slip prevention member , Upper stage slip prevention part of the first embodiment 16 differs from the shape of the lower locking portions 18B of the upper engaging portion 16B and the lower displacement preventing member 18 (square) of.

  FIG. 11 is a specific example of the second modification of the upper stage locking portion 16B of the upper stage locking member 16 of the joint structure 10 according to the first embodiment ((a) the upper stage locking portion 30A, (b) the upper stage locking portion. 30B) is a front view (a front view as seen from the longitudinal direction of the upper shaft portion 16A of the upper shift preventing member 16), and is an example in which the front shape of the upper lock portion is a substantially square shape. Since the shape of the upper shaft portion is the same as that of the upper shaft portion 16A of the upper shift preventing member 16 of the first embodiment, the upper shaft portion is also denoted by reference numeral 16A in FIG. The front shape of the upper locking portion 30A shown in FIG. 11A is a substantially rectangular shape that is long in the horizontal direction perpendicular to the longitudinal direction of the upper shaft portion 16A of the upper slip prevention member, and the vertical length is the upper shaft. The diameter substantially coincides with the diameter in the vertical direction of the portion 16A. The front shape of the upper locking portion 30B shown in FIG. 11B is a substantially rectangular shape that is long in the downward direction in a direction orthogonal to the longitudinal direction of the upper shaft portion 16A, and the horizontal length of the upper shaft portion 16A. It is approximately the same as the horizontal diameter.

  12A and 12B are specific examples of the second modification of the upper stage locking portion 16B of the upper stage locking member 16 of the joint structure 10 according to the first embodiment ((a) the upper stage locking portion 32A, (b) the upper stage locking portion. 32B and (c) is a front view showing the upper locking portion 32C) (a front view seen from the longitudinal direction of the upper shaft portion 16A of the upper slip prevention member 16), and the front shape of the upper locking portion is substantially triangular. It is an example. Since the shape of the upper shaft portion is the same as that of the upper shaft portion 16A of the upper slip prevention member 16 of the first embodiment, the upper shaft portion is also denoted by reference numeral 16A in FIG. The front shape of the upper locking portion 32A shown in FIG. 12 (a) is a substantially triangular shape having a long side in the horizontal direction perpendicular to the longitudinal direction of the upper shaft portion 16A as the upper side, and is shown in FIG. 12 (b). The front shape of the upper locking portion 32B is a substantially triangular shape with a long side in the horizontal direction perpendicular to the longitudinal direction of the upper shaft portion 16A being the lower side, and the front surface of the upper locking portion 32C shown in FIG. The shape is a shape in which two substantially triangular shapes are provided in the horizontal direction orthogonal to the longitudinal direction of the upper shaft portion 16A (on the side surface of the upper joint reinforcement 12).

  FIGS. 13A and 13B are specific examples of the second modification of the upper stage locking part 16B of the upper stage locking member 16 of the joint structure 10 according to the first embodiment ((a) the upper stage locking part 34A, (b) the upper stage locking part. 34B) is a front view (a front view seen from the longitudinal direction of the upper shaft portion 16A of the upper shift preventing member 16), and is an example in which the front shape of the upper lock portion is a substantially egg shape. Since the shape of the upper shaft portion is the same as that of the upper shaft portion 16A of the upper shift preventing member 16 of the first embodiment, the upper shaft portion is also denoted by reference numeral 16A in FIG. The front shape of the upper stage locking portion 34A shown in FIG. 13A is a substantially egg shape in which a portion having a long diameter in the horizontal direction perpendicular to the longitudinal direction of the upper stage shaft portion 16A is arranged upward. The front shape of the upper locking portion 34B shown in b) is a substantially egg shape in which a portion having a long diameter in the horizontal direction perpendicular to the longitudinal direction of the upper shaft portion 16A is disposed below.

  14A and 14B are specific examples of the second modification of the upper stage locking portion 16B of the upper stage locking member 16 of the joint structure 10 according to the first embodiment ((a) the upper stage locking portion 36A, (b) the upper stage locking portion. 36B) is a front view (a front view as seen from the longitudinal direction of the upper shaft portion 16A of the upper shift preventing member 16), and is an example in which the front shape of the upper lock portion is approximately circular and approximately elliptical. Since the shape of the upper shaft portion is the same as that of the upper shaft portion 16A of the upper shift preventing member 16 of the first embodiment, the upper shaft portion is also denoted by reference numeral 16A in FIG. The front shape of the upper locking portion 36A shown in FIG. 14 (a) is a circle whose upper end coincides with the upper end of the upper shaft portion 16A, and the front shape of the upper locking portion 36B shown in FIG. 14 (b) is The oval shape is long in the horizontal direction perpendicular to the longitudinal direction of the upper shaft portion 16A.

  In addition, the front shape of the specific example of the 2nd modification of the lower stage locking part 18B of the lower stage locking member 18 of the joint structure 10 which concerns on 1st Embodiment concerns on 1st Embodiment shown in FIGS. Since the specific example of the 2nd modification of the upper stage latching | locking part 16B of the upper stage latching member 16 of the joint structure 10 is turned upside down, illustration and description are abbreviate | omitted.

(Second Embodiment)
FIG. 15 is a perspective view of the joint structure 40 of the precast concrete floor slab according to the second embodiment of the present invention viewed obliquely from above, and FIG. 16 excludes the upper and lower orthogonal reinforcing bars 20 and 22 from FIG. FIG. 17 is a side view of the joint structure 40 of the precast concrete floor slab according to the second embodiment of the present invention as viewed from the direction perpendicular to the bridge axis. However, for the sake of illustration, the interstitial concrete 24 is not drawn in FIGS. 15 and 16. Moreover, in FIG. 17, the member inside the interstitial concrete 24 is also drawn with the continuous line. Moreover, about the structure similar to the joint structure 10 of the precast concrete floor slab which concerns on 1st Embodiment of this invention, the same code | symbol is attached | subjected and description is abbreviate | omitted in principle. In addition, among the contents described in the joint structure 10 of the precast concrete floor slab according to the first embodiment, the same applies to the joint structure 40 of the precast concrete floor slab according to the second embodiment in principle. Is omitted.

  An upper slip prevention member 42 is provided at the tip of the upper joint rebar 12. FIG. 18 is a vertical cross-sectional view schematically showing a cross section obtained by cutting the distal end portion of the upper joint rebar 12 and the upper shift preventing member 42 with a vertical plane passing through the central axis 12A of the upper joint rebar 12.

  As shown in FIG. 18, the upper slip prevention member 42 includes an upper shaft portion 42A and an upper latch portion 42B. The upper shaft portion 42A and the upper locking portion 42B are integrated.

  The upper stage locking member 16B of the upper stage locking member 16 of the joint structure 10 of the precast concrete floor slab according to the first embodiment includes the upper stage joint reinforcing bar 12 provided with the upper stage locking member 16 having the upper stage locking unit 16B. Although the upper inner surface 16B1 extending obliquely downward in the direction opposite to the projecting direction is provided on the side opposite to the direction in which the upper joint rebar 12 projects, the second embodiment as shown in FIG. The upper stage locking part 42B of the joint structure 40 of the precast concrete floor slab according to the configuration is in a direction opposite to the direction in which the upper stage joint reinforcing bar 12 provided with the upper stage locking member 42 having the upper stage locking part 42B is projected. The surface extending obliquely downward (the upper inner surface 16B1 in the joint structure 10 according to the first embodiment) is not provided, but is substantially orthogonal to the longitudinal direction of the upper joint rebar 12 instead. It has the opposite side of the upper orthogonal inner surface 42B1 extending downward and the projecting direction of the upper joint reinforcement 12 so that.

  Further, a lower-stage detent member 44 is provided at the tip of the lower joint rebar 14. FIG. 19 is a vertical cross-sectional view schematically showing a cross section obtained by cutting the distal end portion of the lower joint rebar 14 and the lower shift preventing member 44 along a vertical plane passing through the central axis 14A of the lower joint rebar 14.

  As shown in FIG. 19, the lower-stage slip prevention member 44 includes a lower-stage shaft portion 44A and a lower-stage locking portion 44B. The lower shaft portion 44A and the lower locking portion 44B are integrated.

  The lower-stage locking member 18B of the lower-stage locking member 18 of the precast concrete floor slab joint structure 10 according to the first embodiment includes a lower-level joint reinforcing bar 14 provided with a lower-level locking member 18 having a lower-level locking part 18B. Although the lower inner surface 18B1 extending obliquely upward in the direction opposite to the projecting direction is provided on the side opposite to the direction in which the lower joint rebar 14 projects, the second embodiment as shown in FIG. The lower stage locking portion 44B of the joint structure 40 of the precast concrete floor slab according to the configuration is in a direction opposite to the direction in which the lower joint reinforcing bar 14 provided with the lower stage stopper member 44 having the lower stage locking portion 44B protrudes. The surface extending obliquely upward (the lower inner surface 18B1 in the joint structure 10 according to the first embodiment) is not provided, but instead is substantially orthogonal to the longitudinal direction of the lower joint rebar 14. It has the opposite side of the lower orthogonal inner surface 44B1 extending upwardly direction to protrude in the lower joint reinforcement 14 so that.

  As described above, in place of the upper inner surface 16B1, the upper joint inner reinforcing surface 14 has the upper orthogonal inner surface 42B1 that extends downward so as to be substantially orthogonal to the longitudinal direction of the upper joint reinforcing bar 12, and instead of the lower inner surface 18B1, the length of the lower joint reinforcing bar 14 is increased. The joint of the precast concrete floor slab according to the first embodiment of the joint structure 40 of the precast concrete floor slab according to the second embodiment is that it has a lower orthogonal inner surface 44B1 extending upward so as to be substantially orthogonal to the direction. This is a major difference from the structure 10.

  By providing the upper-stage orthogonal inner surface 42B1 with the upper-stage shift preventing member 42, the upper-stage orthogonal inner surface 42B1 serves as a bearing resistance surface to prevent the upper-stage joint rebar 12 from being pulled out from the interstitial concrete 24, and the lower-stage shift preventing member 44 Since the lower-stage orthogonal inner surface 44B1 is provided, the lower-stage orthogonal inner surface 44B1 serves as a bearing resistance resistance surface, and the lower joint reinforcing bar 14 is prevented from being pulled out from the interstitial concrete 24.

  The shape of the upper locking portion 42B viewed from the side (in the direction perpendicular to the bridge axis) is a wedge shape, and the upper locking portion 42B of the joint structure 40 of the precast concrete slab according to the second embodiment is orthogonal to the upper stage. The upper outer surface 42B2 on the side opposite to the inner surface 42B1 (the side in the direction in which the upper joint rebar 12 having the upper locking member 42 having the upper locking portion 42B protrudes) is the upper shift having the upper locking portion 42B. The upper joint rebar 12 provided with the stop member 42 is a surface extending obliquely downward in the protruding direction. For this reason, when the upper joint rebar 12 tries to protrude upward, the upper outer surface 42B2 receives a resistance force from the interstitial concrete 24, so that the upper joint rebar 12 does not easily protrude upward. .

  The shape of the lower locking portion 44B viewed from the side (in the direction perpendicular to the bridge axis) is a wedge shape, and the lower locking portion 44B of the lower locking portion 44B of the precast concrete slab joint structure according to the second embodiment is orthogonal to the lower step. The lower outer surface 44B2 on the side opposite to the inner surface 44B1 (the side in the direction in which the lower joint reinforcing bar 14 provided with the lower shift preventing member 44 having the lower locking portion 44B protrudes) is the lower shift having the lower locking portion 44B. It is a surface that extends obliquely upward in the direction in which the lower joint rebar 14 provided with the stop member 44 projects. For this reason, when the lower joint rebar 14 attempts to protrude downward, the lower outer surface 44B2 receives a resistance force from the interstitial concrete 24, so that the lower joint reinforcing bar 14 does not easily protrude downward. .

  However, the upper stage locking portion 42B of the upper stage locking member 42 of the joint structure 40 of the precast concrete floor slab according to the second embodiment is an upper stage joint provided with an upper stage locking member 42 having an upper stage locking portion 42B. A surface (upper inner surface 16B1 in the joint structure 10 according to the first embodiment) extending obliquely downward in a direction opposite to the direction in which the reinforcing bar 12 protrudes is provided on the side opposite to the direction in which the upper connecting reinforcing bar 12 protrudes. Instead, it has an upper orthogonal inner surface 42B1 extending downward so as to be substantially orthogonal to the longitudinal direction of the upper joint rebar 12 on the side opposite to the direction in which the upper joint rebar 12 protrudes, Further, the lower-stage locking member 44B of the lower-stage locking member 44 of the joint structure 40 of the precast concrete floor slab according to the second embodiment includes a lower-stage locking part having a lower-level locking part 44B. The lower joint rebar 14 protrudes from a surface (lower inner surface 18B1 in the joint structure 10 according to the first embodiment) extending obliquely upward in a direction opposite to the direction in which the lower joint rebar 14 in which the member 44 is provided protrudes. Instead, the lower joint inner reinforcing surface 14B1 extending upward so as to be substantially perpendicular to the longitudinal direction of the lower joint rebar 14 is defined as the direction in which the lower joint rebar 14 protrudes. Since the joint structure 40 of the precast concrete floor slab according to the second embodiment is engaged with the interstitial concrete 24 rather than the joint structure 10 of the precast concrete floor slab according to the first embodiment. It seems that the effect of stopping becomes smaller.

  The upper shaft portion 42A of the upper shift stopper 42 has an outer diameter that is substantially the same as the outer diameter of the upper joint rebar 12 (the outer diameter of the recess). Are joined so that their central axes substantially coincide. This joining can be performed using flash welding, for example. The joint obtained by flash welding has a slightly larger diameter than before the joining, but the joint obtained by flash welding can be obtained by suppressing the diameter to the extent of the convex portion of the upper joint rebar 12 or less. A cover equivalent to 12 can be secured.

  Further, the lower shaft portion 44A of the lower slip stopper 44 has an outer diameter substantially the same as the outer diameter of the lower joint rebar 14 (the outer diameter of the concave portion). Are joined so that their central axes substantially coincide. This joining can be performed using flash welding, for example. The joint obtained by flash welding has a slightly larger diameter than before the joining, but the joint obtained by flash welding has a lower joint rebar by suppressing it to about the diameter of the convex portion of the lower joint rebar 14. A cover equivalent to 14 can be secured.

  In addition, as the front shape of the upper-stage shift preventing member 42 and the lower-stage shift preventing member 44 of the joint structure 40 of the precast concrete floor slab according to the second embodiment, the joint structure 10 of the precast concrete floor slab according to the first embodiment is used. Various shapes can be adopted in the same manner as in FIGS.

DESCRIPTION OF SYMBOLS 10, 40 ... Joint structure of precast concrete floor slab 12 ... Upper joint rebar 12A, 14A ... Center axis 14 ... Lower joint rebar 16, 26, 42 ... Upper stage slip prevention member 16A, 26A, 42A ... Upper stage shaft part 16B, 26B, 42B: Upper stage locking portion 16B1, 26B1 ... Upper stage inner surface 16B2, 26B2, 42B2 ... Upper stage outer surface 18, 28, 44 ... Lower stage locking member 18A, 28A, 44A ... Lower stage shaft part 18B, 28B, 44B ... Lower stage locking part 18B1 , 28B1 ... Lower inner surface 18B2, 28B2, 44B2 ... Lower outer surface 20 ... Upper orthogonal reinforcing bar 22 ... Lower orthogonal reinforcing bar 23 ... Wire 24 ... Filled concrete 30A, 30B, 32A, 32B, 32C, 34A, 34B, 36A, 36B ... Upper Locking part 42B1 ... Upper orthogonal inner surface 44B1 ... Lower orthogonal inner surface 50 ... Pre Turbocharger strike concrete floor slab 52 ... joining end face

Claims (6)

The upper stage which is embedded in the joint end surface of the side end portion of the precast concrete floor slab with a space in the vertical direction and is arranged so as to protrude from the joint end surface in a direction substantially parallel to the floor plate surface of the precast concrete floor slab. A joint reinforcing bar and a lower joint reinforcing bar, and a filling material for filling a space between the joint end faces of the precast concrete floor slab arranged so that the joint end faces face each other, and the joint end face is A joint structure of precast concrete floor slabs connecting the precast concrete floor slabs arranged to face each other,
The upper joint rebars of the precast concrete floor slabs arranged so that the joining end faces face each other are arranged at substantially the same height position with a predetermined interval,
The lower joint reinforcing bars of the precast concrete floor slabs arranged so that the joint end faces face each other are arranged at predetermined intervals at substantially the same height position,
At the tip of the protruding upper joint reinforcing bar, an upper slip prevention member is provided, respectively.
The upper-stage detent member includes an upper shaft portion joined so that the central axes of the upper-stage joint reinforcing bars are substantially coincided with each other, and a horizontal direction perpendicular to the longitudinal direction of the upper joint reinforcing bar to which the upper-stage displacement preventing member is joined. An upper locking portion having an upper inner surface extending obliquely downward in a direction opposite to the direction in which the upper joint reinforcing bar protrudes from the direction opposite to the direction in which the upper joint reinforcing bar protrudes. And
The upper shaft portion and the upper locking portion are integrated,
At the tip of the protruding lower joint rebar, a lower slip prevention member is provided,
The lower-stage detent member includes a lower-stage shaft portion joined so that the central axes of the lower-stage joint reinforcing bars substantially coincide with each other, and a horizontal direction perpendicular to the longitudinal direction of the lower-joint reinforcing bar to which the lower-stage slip prevention member is joined. A lower locking portion having a lower inner surface extending obliquely upward in a direction opposite to the direction in which the lower joint reinforcing bar protrudes from the direction opposite to the direction in which the lower joint reinforcing bar protrudes. And
The lower shaft portion and the lower locking portion are integrated,
Further, an upper orthogonal reinforcing bar that is arranged adjacent to the lower part of the upper joint reinforcing bar and extends in a substantially horizontal direction substantially orthogonal to the longitudinal direction of the upper joint reinforcing bar is arranged between the upper locking portions.
A lower orthogonal reinforcing bar that is disposed adjacent to and above the lower joint reinforcing bar and extends in a substantially horizontal direction substantially orthogonal to the longitudinal direction of the lower joint reinforcing bar is disposed between the lower locking portions;
The portion of the upper joint reinforcing bar protruding from the joint end surface of the precast concrete floor slab, the portion of the lower joint reinforcing bar protruding from the joint end surface of the precast concrete floor slab, the upper stage detent member, the lower stage detent member The surroundings of the member, the upper orthogonal reinforcing bar, and the lower orthogonal reinforcing bar are covered with the padding material ,
The upper-stage locking portion of the upper-stage detent member is arranged in a horizontal direction perpendicular to the longitudinal direction of the upper-stage joint reinforcing bar to which the upper-stage detent member is joined, on the side in the direction in which the upper-stage joint rebar is joined. As viewed from the direction, it has an upper outer surface that extends obliquely downward in the direction in which the upper joint reinforcing bar protrudes, and the lower locking portion of the lower locking member is a lower stage to which the lower locking member is joined. A lower outer surface extending obliquely upward in a direction in which the lower joint reinforcing bar protrudes when viewed from a horizontal direction orthogonal to the longitudinal direction of the lower joint reinforcing bar to which the lower reinforcing bar is joined, on the side in which the joint reinforcing bar protrudes. A joint structure for precast concrete slabs.   A central axis of the upper joint reinforcing bar of the upper inner surface of the upper locking portion of the upper shift preventing member joined to the upper joint reinforcing bar in a cut surface cut along a vertical plane including the central axis of the upper joint reinforcing bar The lower-stage engagement member of the lower-stage detent member joined to the lower-joint reinforcing bar at a cut surface cut by a vertical plane including the central axis of the lower-joint reinforcing bar is 45 ° to 85 °. The joint structure of the precast concrete slab according to claim 1, wherein an angle between the lower inner surface of the stopper and the central axis of the lower joint reinforcing bar is 45 ° or more and 85 ° or less.   The upper slip prevention member does not have a portion positioned above the upper edge of the upper joint rebar to which it is joined, and the lower slip restraining member has the part of the lower joint rebar to which it is joined. The joint structure for a precast concrete slab according to claim 1 or 2, wherein there is no portion located below the lower edge.   The joint structure of the precast concrete floor slab according to any one of claims 1 to 3, wherein the upper locking portion and the lower locking portion are plate-shaped. Wherein the upper displacement preventing member is integrally formed of cast iron or cast steel, the lower displacement preventing member according to any one of claims 1 to 4, characterized in that it is integrally formed of cast iron or cast steel Joint structure of precast concrete floor slab. The upper shaft portion of the upper shift prevention member is joined to the tip of the protruding upper joint rebar by flash welding, and the lower shaft portion of the lower shift prevention member is the protrusion of the lower joint reinforcing rod. The joint structure of a precast concrete slab according to any one of claims 1 to 5 , wherein the joint structure is joined to the tip by flash welding.

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