JP6567277B2 - Connection structure and precast block - Google Patents

Description

  The present invention relates to a connection structure between precast blocks and a precast block.

  A precast block may be connected and used as a structure such as a wall. The connection between the precast blocks is performed using, for example, a mechanical joint (see, for example, Patent Document 1).

  An example of connection by a mechanical joint is shown in FIG. In this example, as shown in FIG. 14A, the precast blocks 100 are arranged on the left and right sides, and the reinforcing bars 101 and 103 protruding from the opposite side surfaces of both the precast blocks 100 are abutted. Then, the coupler 102 attached in advance to one of the reinforcing bars 101 is connected to the reinforcing bar 103 as shown in FIG. 14B, and then concrete is placed between the two precast blocks 100 to form joints.

JP 10-331172 A

  The protrusion length of the reinforcing bar 103 to be connected needs to be about ½ of the length L (for example, about 300 to 600 mm) of the coupler 102. Accordingly, as shown in FIG. 14A, a distance of at least (L + L / 2) is required between the precast blocks 100, and the amount of concrete to be cast as joints is large, which takes time for construction. In addition, the increase in the amount of concrete placed causes a problem that the heat of hydration is large and the temperature is cracked.

  Further, in Patent Document 1, a horizontal plate-like member protrudes from the precast block in addition to the reinforcing bars, and this plate-like member may interfere with placing concrete as a joint.

  An object of this invention is to provide the connection structure etc. which can perform construction of a joint easily.

A first invention for solving the above-described problem is a connection structure in which a pair of precast blocks are arranged side by side, and reinforcing bars protruding from each of the opposing side surfaces of both precast blocks are connected by a coupler, of the pair of precast blocks, a horizontal recess provided on the side of the hand of the precast blocks are the reinforcing bar projects from the recess, the said side of the other precast block planar surface, said recess, When viewed along the vertical direction, the upper surface is inclined upward from the bottom surface of the recess toward the outside of the member, and a filler is filled between the two precast blocks, and the recess has an inner wall on the entire circumference. and, protruding length of the reinforcing bars protruding from the recess, characterized in that greater protruding length of the reinforcing bars protruding from the flat surface It is a connection structure.

In the connection structure of the present invention, since the reinforcing bar protrudes from the recess of the precast block, the distance between the precast blocks can be reduced by the depth of the recess, the amount of filler used as a joint is reduced, and temperature cracking is also suppressed. it can. The recesses, when viewed in the vertical direction, the upper surface than you are inclined upward, not to interfere with the filling of the filling material. As a result, joints can be easily constructed between the precast blocks.

In the present invention , for example, when a mortar injection type coupler is used, confirmation of completion of mortar injection can be easily performed. The same applies to the case where a connection using a screw-type coupler is performed and a resin or the like is injected into the coupler.

Further, another pair of precast blocks is arranged on the upper or lower stage of the pair of precast blocks, and the pair of precast blocks are connected to each other by reinforcing the reinforcing bars protruding from the opposite side surfaces of the two precast blocks with a coupler. The upper and lower precast blocks are connected by filling a filler between the two precast blocks, and the reinforcing bars protruding from the lower surface of the upper precast block are inserted into the holes provided on the upper surface of the lower precast block. However, it is desirable to connect the precast blocks and between the holes by filling the filler.
Alternatively, another pair of precast blocks is arranged above or below the pair of precast blocks, and the other pair of precast blocks is connected to the reinforcing bars protruding from the opposite side surfaces of both precast blocks by a coupler. The upper and lower precast blocks are connected to each other by filling a filler between the two precast blocks. The upper and lower precast blocks are connected to the inner hole of the embedded coupler provided on the lower surface of the upper precast block and the lower precast block. It is also desirable that both ends of the connector are respectively inserted into holes inside the embedded coupler provided on the upper surface, and a filler is filled between the two precast blocks.
In this way, when connecting the upper and lower precast blocks by inserting reinforcing bars or connectors into holes provided directly in the block or inside the coupler embedded in the block, the precast block can be moved to the left or right. Since this is not possible, it is particularly effective to connect the left and right precast blocks with a coupler using the present invention.

The pair of precast blocks and the another pair of precast blocks have different diameters of the reinforcing bars and the couplers, and the pair of precast blocks and the other pair of precast blocks It is desirable that the positions of the side surfaces are aligned.
The another pair of precast blocks are also connected by the connection structure according to the first aspect of the present invention, and the pair of precast blocks and the other pair of precast blocks have a large diameter of the reinforcing bar and the coupler. It is desirable that the depth of the concave portion with a longer length is larger than the depth of the concave portion with a smaller diameter of the reinforcing bar and a shorter coupler.
Depending on the force applied to the structure, the upper and lower precast blocks may change the diameter of the rebar and the length of the coupler. Even in such a case, in the present invention, by providing the recess in the precast block, the distance between the precast blocks can be kept small, and the positions of the side surfaces of the upper and lower precast blocks can be aligned.

The second invention, reinforcing bars protrude from the right and left sides, a precast block coupler is provided for connection to the reinforcing bars of one side, the side surface sac Chi hand of the left and right of the precast block, horizontal The concave portion is provided, the reinforcing bar protrudes from the concave portion, the other side surface is a flat surface, and the concave portion is inclined upward from the bottom surface of the concave portion toward the outside of the member when viewed along the vertical direction. and is, the recess may have a inner wall all around, protruding length of the reinforcing bars protruding from the recess, in precast block, wherein the larger projecting length of the reinforcing bars protruding from the flat surface is there.

  According to the present invention, it is possible to provide a connection structure or the like that allows easy construction of joints.

Diagram showing precast block 1 Diagram showing connection of block 1 The figure which shows filling of the filler 20 Diagram showing LNG tank 200 Diagram showing connection of block 1 Diagram showing upper and lower blocks The figure which shows the recessed part 10a, 10b, 10c The figure which shows the precast block 1a The figure which shows the precast block 1b The figure which shows the precast block 1c The figure which shows the precast block 1d The figure which shows the precast block 1e The figure which shows the precast block 1f The figure which shows the connection of the precast block 100

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

[First embodiment]
(1. Precast block 1)
FIG. 1 is a diagram showing a precast block (hereinafter sometimes referred to as a block) 1 according to the first embodiment of the present invention. 1A is a view of the block 1 as viewed from the front, and FIG. 1B is a view of the right side of the block 1 as viewed.

  The block 1 of the present embodiment is obtained by providing reinforcing bars 11, 13, 14 and holes 15 in a main body which is a rectangular plate-like concrete member.

  A horizontal concave portion 10 is provided on the right side surface of the main body, and the reinforcing bar 11 protrudes from the concave portion 10. A plurality of the recesses 10 and the reinforcing bars 11 are provided at intervals along each of a plurality of rows in the vertical direction (two rows in the example in the figure). The depth of the recess 10 is, for example, about 100 to 200 mm.

  The shape of the recess 10 is such that the upper part of the quadrangular pyramid is cut to make the cut surface the bottom surface of the recess 10, and the top surface is upward from the bottom surface of the recess toward the outside of the member when viewed along the vertical direction. It is inclined to. The lower surface is inclined downward from the bottom surface of the recess toward the outside of the member. A coupler 12 for connection is attached to the reinforcing bar 11 in advance, and the width of the bottom surface of the recess 10 is larger than the outer diameter of the coupler 12.

  The left side surface of the main body is a flat surface, and the reinforcing bar 13 to be connected by the coupler 12 protrudes from the left side surface. When the length of the coupler 12 is L, the protruding length of the reinforcing bar 13 is set to about L / 2.

  The reinforcing bar 14 protrudes from the lower surface of the main body. The hole 15 is for inserting the reinforcing bar 14 and is provided on the upper surface of the main body.

(2. Connection structure 30)
FIG. 2 is a diagram showing the connection of the block 1. In the present embodiment, a pair of blocks 1 are arranged side by side in the same manner as described above, and the reinforcing bars 11 and 13 on the opposite side surfaces of both blocks 1 are connected by a coupler 12.

  In this embodiment, since the reinforcing bar 11 is provided in the recess 10, as shown in FIG. 2A, the distance between the blocks 1 is made smaller than (L + L / 2) by the depth of the recess 10. The left and right blocks 1 can be arranged.

  Thereafter, the coupler 12 is pulled out from the reinforcing bar 11 and connected to the reinforcing bar 13 as shown in FIG. In this embodiment, the coupler 12 is of a mortar injection type. After the coupler 12 is pulled out from the reinforcing bar 11 and externally fitted to the reinforcing bar 13, the mortar is injected into the coupler 12. Completion confirmation of mortar injection is performed by visually observing that the mortar overflows from the coupler 12 along the side surface of the block 1 on the reinforcing bar 13 side.

  After the rebars 11 and 13 are connected by the coupler 12, a filler 20 is filled between the blocks 1 as shown in FIG. The filler 20 is, for example, concrete. Filler 20 is filled from bottom to top. Since the upper surface of the recess 10 is inclined upward, the filler 20 flows smoothly along the inclination of the upper surface as indicated by the arrow A, and filling is not hindered. In this way, joints between the blocks 1 are formed, and as shown in FIG. 3B, a connection structure 30 by the left and right blocks 1 is formed.

(3. Construction of breakwater 2 by block 1)
Next, an example of building a breakwater for PC (prestressed concrete) tank using block 1 will be described.

  The PC tank is a facility for storing liquids such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas). FIG. 4 shows an example of an LNG tank 200 that stores LNG as a PC tank. The LNG tank 200 is provided with a liquid breakwater 2 on a bottom slab 5 supported by a pile 4 in the ground 7, and an inner tub 3a and an outer tub 3b made of a steel plate or the like inside. LNG is stored in the inner tank 3a, and a heat insulating material is disposed between the inner tank 3a and the outer tank 3b to perform cold insulation.

  The breakwater 2 is provided to prevent leakage of LNG to the outside when the inner tank 3a is damaged, and is generally cylindrical. In the present embodiment, the breakwater 2 is constructed using the block 1. In this case, the main body of the block 1 has a slight arc-shaped warp corresponding to the diameter of the tank.

  FIG. 5 shows the construction of the breakwater 2 by the block 1. In this example, as shown in FIGS. 5A and 5B, a new block 1 is placed on the lower block 1 by inserting the lower reinforcing bar 14 into the hole 15 on the upper surface of the lower block 1. To do. In the same manner as described above, the reinforcing bars 11 and 13 of the block 1 arranged side by side are connected by the coupler 12.

  Thereafter, as shown in FIG. 5C, the filler 20 is filled between the upper and lower blocks 1 including the inside of the hole 15, and the filler 20 is filled between the left and right blocks 1. By repeating the connection of the left and right blocks 1 and the upper and lower blocks 1 in this manner, the connection structure 40 by the upper, lower, left and right blocks 1 is formed.

  That is, in the connection structure 40, the pair of left and right blocks 1 are connected to each other by connecting the reinforcing bars 11 and 13 with the coupler 12 and filling the filler 20 between the blocks 1 in each of the upper and lower stages. Further, the upper and lower blocks 1 are connected by inserting the reinforcing bars 14 of the upper block 1 into the holes 15 of the lower block 1 and filling the holes 15 and the blocks 1 with the filler 20.

  In this way, the blocks 1 are arranged side by side in the circumferential direction of the breakwater 2 and stacked in the upper and lower stages, and joints are formed between the adjacent blocks 1, thereby constructing the breakwater 2. In the breakwater 2, prestress is introduced by a tension material (not shown) in the circumferential direction and the vertical direction in order to have a structure that can withstand the hydraulic pressure of LNG. The main body of the block 1 is also provided with a sheath tube (not shown) for passing the tendon.

(4. Sides of the upper and lower blocks 1)
In the breakwater 2, it is desirable from the viewpoint of construction surface, strength, etc. that the width of the joint is made constant across the top and bottom and the side face of the block is aligned. On the other hand, the force such as the hydraulic pressure applied to the breakwater 2 differs depending on the height position of the breakwater 2, and the diameter of the reinforcing bars for connecting the blocks and the length of the coupler may be changed accordingly. is there. That is, at a position where a larger force is applied, the diameter of the reinforcing bar is made larger and a longer coupler is used.

  Since the minimum necessary distance between the blocks is determined to be about 1.5 times the length L of the coupler as described above, the minimum necessary distance between the blocks varies depending on the height position in the above case.

  Therefore, when the concave portion is not provided as in the block 100 of FIG. 14, the coupler is the longest in order to align the distance between the left and right blocks across the top and bottom of the breakwater 2 and to align the position of the side surface of the block. With the distance at the height position as a reference, it is necessary to match the distance at other height positions, and an extra joint width is formed.

  However, in this embodiment, by providing the recess 10 in the block 1, even when the connecting reinforcing bar has a different diameter and the coupler has a different length, the side surface of the block can be aligned vertically while reducing the joint width. Can do.

  FIG. 6 shows an example of this, and in the example of FIG. 6 (a), the diameter of the reinforcing bar increases in the order of the middle layer, the higher layer, and the lower layer, and the coupler becomes longer. In FIG. 6A, the depth of the concave portion 10 is determined so that the distance between the blocks 1 of the other layers is also D1, with reference to the distance D1 between the blocks 100 of the middle layer where the coupler 102 is the shortest. . The depth of the recess 10 of the block 1 in the low layer where the coupler 12 is the longest is larger than the depth of the recess 10 of the block 1 in the high layer where the length of the coupler 12 is medium.

  Also in the example of FIG. 6B, the diameter of the reinforcing bar increases in the order of the middle layer, the higher layer, and the lower layer, and the coupler becomes longer. In this example, the distance D2 between the higher layer blocks 100 in which the coupler 102 has a medium length. , The depth of the recess 10 in the low-layer block 1 is determined so as to match this distance.

  In the example of FIG. 6C, the diameter of the reinforcing bar is larger in the order of the high layer, the middle layer, and the lower layer, the coupler is longer, and the other layer is based on the distance D3 between the blocks 100 of the highest layer where the coupler 102 is the shortest. The depth of the recess 10 is determined so that the distance between the blocks 1 is also D3. The depth of the concave portion 10 of the block 1 in the low layer where the coupler 12 is the longest is determined to be larger than the concave portion 10 of the block 1 in the middle layer where the length of the coupler 12 is medium.

  As described above, in this embodiment, since the reinforcing bar 11 protrudes from the recess 10 of the block 1, the distance between the blocks 1 can be reduced by the depth of the recess 10, and the amount of the filler 20 used as a joint And temperature cracking can be suppressed. In addition, there is an advantage that the formwork span at the time of filling the filler 20 can be reduced, and the shear strength is improved by the filler 20 filled in the recess 10.

  Moreover, since the upper surface is inclined upward when viewed along the vertical direction, the recess 10 does not interfere with the filling of the filler 20. As a result, joints can be easily constructed between the blocks 1.

  Further, in this embodiment, the upper and lower blocks 1 are connected by inserting the reinforcing bars 14 into the holes 15, but in this case, the blocks 1 cannot be moved to the left and right, so that the left and right blocks 1 as in the present embodiment. It is particularly effective to connect the two with a coupler 12.

  Even when the diameter of the reinforcing bar and the length of the coupler are changed in the upper and lower blocks by the force applied to the breakwater 2, the distance between the blocks 1 can be kept small by providing the recess 1 in the block 1 and the upper and lower blocks The positions of the side surfaces of the block 1 can be aligned.

  However, the present invention is not limited to this. For example, in this embodiment, the block 1 is used to construct the breakwater 2 of the LNG tank 200, but the block 1 is a cylindrical structure such as a side wall of another storage tank, or other structure such as a wall body. Applicable to objects. Moreover, although the recessed part 10 was provided in the right side surface of the main body, it can replace with this and can also be provided in the left side surface of the main body. Furthermore, although the mortar injection type | mold was used for the coupler 12, the screw type screwed together with the reinforcing bars 11 and 13 may be used. In this case, screws are provided on the outer peripheral surfaces of the reinforcing bars 11 and 13, and screw holes that are screwed into the screws of the reinforcing bars 11 and 13 are provided inside the coupler 12. As the reinforcing bars 11 and 13, in addition to a reinforcing bar with a threaded end, a threaded reinforcing bar in which the reinforcing bar has a screw shape can be used, and a coupler dedicated to the above-described screwed reinforcing bar can be used as the coupler 12. It is. When connecting the reinforcing bars 11, 13, the coupler 12 is rotated and pulled out from the reinforcing bar 11 and externally fitted to the reinforcing bar 13, and then a filler such as resin is injected into the coupler 12.

  Hereinafter, other examples of the present invention will be described as second to fifth embodiments. Each embodiment will be described with respect to differences from the first embodiment, and description of similar points will be omitted. In addition, the configurations of the embodiments including the first embodiment can be used in combination as necessary.

[Second Embodiment]
As the second embodiment, an example in which the shape of the concave portion of the block is different will be described with reference to FIGS.

  FIG. 7A shows an example in which the bottom surface of the recess 10a has an arc shape having a curve that is continuous with the inclination of the top and bottom surfaces when viewed along the vertical direction. FIG. 7B is an example in which the lower surface of the recess 10b is a horizontal plane. In the example of FIG. 7C, the shape of the recess 10c is such that the upper part of the cone is cut and the cut surface is the bottom surface of the recess 10c.

  FIG. 8 is a diagram showing the precast block 1a. FIG. 8A is a view of the block 1a as viewed from the front, and FIG. 8B is a view of the right side of the block 1a as viewed. In this example, the recess in the horizontal direction does not have an upper surface, and a groove 10d that is continuous between the upper and lower ends of the block 1a is formed.

  In each example, points other than the recesses are the same as in the first embodiment, and as in the first embodiment, when connecting the left and right blocks, the distance between the blocks can be reduced, and the filling of the filler is performed. The effect that the construction of joints becomes easy without being hindered is obtained.

[Third embodiment]
FIG. 9A illustrates a precast block 1b according to the third embodiment. In the block 1 b, horizontal recesses 10 are provided on the left and right side surfaces, and the reinforcing bars 11 and 13 protrude from the recesses 10.

  By providing the concave portions 10 on the left and right side surfaces as described above, as shown in FIG. 9B, the distance between the blocks 1b can be further shortened when the left and right blocks 1b are connected. However, when a mortar injection type is used for the coupler 12, when the mortar injection into the coupler 12 is completed, the mortar overflows from the coupler 12 into the concave portion 10 on the reinforcing bar 13 side as shown by the arrow B. A little difficult to do in. In this respect, it is easier to confirm the completion of mortar injection when the side surface of the block 1 on the reinforcing bar 13 side is flat as in the first embodiment. The same applies to the case where the connection using the screw type coupler is performed as described above and the resin or the like is injected into the coupler.

[Fourth Embodiment]
In the first embodiment, an example of constructing the liquid breakwater 2 (wall body) using the block 1 has been described, but the block of the present invention is applicable to other than the wall body. In the fourth embodiment, an example of a block used for a floor structure will be described.

  The main body of the precast block 1c in FIG. 10 (a) is a rectangular plate in the horizontal direction, and a concave portion 10 and a reinforcing bar 11 similar to those of the first embodiment are provided on one side surface. A plurality of the recesses 10 and the reinforcing bars 11 are provided at intervals along the width direction of the side surface. The recesses 10 and the reinforcing bars 11 are arranged in a plurality of stages (two stages in the example in the figure). A coupler 12 is attached to the reinforcing bar 11 in advance.

  On the opposite side surface of the main body, a reinforcing bar 13 (not shown) similar to that of the first embodiment is provided at a position corresponding to the reinforcing bar 11.

  In order to connect the blocks 1c to each other, for example, as shown by an arrow C in FIG. 10B, one of the blocks 1c (the block 1c on the right side in the example in the figure) is moved in the vertical direction. While maintaining the horizontal distance between them at the required joint width, the positions of the reinforcing bars 11 and 13 on the opposite side surfaces of both blocks 1c are matched. Thereafter, the reinforcing bars 11 and 13 are connected by the coupler 12 in the same procedure as in the first embodiment, and a filler is filled between the blocks 1c to form joints. By repeating this, it is possible to construct a floor structure.

  Alternatively, when aligning the positions of the reinforcing bars 11 and 13 on the opposite side surfaces of both blocks 1c, as shown by an arrow D in FIG. 10 (c), one block 1c (right block 1c in the example in the figure) The horizontal distance between the blocks 1c may be slid in the width direction of the side surface where the reinforcing bars 13 (not shown) of the block 1c are provided while maintaining the required joint width value. Of course, the other block 1c (the left block 1c in the example in the figure) can be slid in the width direction of the side surface of the block 1c where the reinforcing bars 11 are provided in the same manner as described above.

  A precast block 1d in FIG. 11 is different from the block 1c in FIG. 10A in that the groove 10d described above is provided instead of the recess 10. This block 1d can also be connected in the same manner as described above.

  Also in the fourth embodiment described above, as in the first embodiment, when connecting the left and right blocks, the distance between the blocks can be reduced, and filling of the filler is not hindered, and joint construction is facilitated. Effects such as can be obtained.

[Fifth Embodiment]
In the first embodiment, when the upper and lower blocks 1 are connected, the upper block 1 is moved downward, and the reinforcing bars 14 on the lower surface of the main body are inserted into the holes 15 on the upper surface of the main body of the lower block 1. However, the present invention is not limited to this, as long as it is accompanied by movement of a block in the vertical direction. In the fifth embodiment, another example of connecting the upper and lower blocks will be described.

  The precast block 1e of FIG. 12A differs from the block 1 of the first embodiment in that an embedded coupler 16 is provided instead of forming the hole 15 directly on the upper surface of the main body. The embedded coupler 16 is cylindrical and has a hole 16a on the inside. The upper end of the reinforcing bar 14 is inserted into the lower end portion of the embedded coupler 16.

  When the upper and lower blocks 1e are connected, the upper block 1e is moved downward as shown by an arrow E in FIG. 12B, and the reinforcing bar 14 on the lower surface of the main body is moved to the embedded coupler 16 on the upper surface of the main body of the lower block 1e. Into the hole 16a. Thereafter, a filler may be injected into the holes 16a to form joints between the blocks 1e.

  The precast block 1f of FIG. 13A is provided with embedded couplers 16 on both the upper surface and the lower surface of the main body. A reinforcing bar 17 is also provided in the body, and the upper end of the reinforcing bar 17 is inserted into the lower end portion of the embedded coupler 16 on the upper surface of the main body, and the lower end of the reinforcing bar 17 is inserted into the upper end portion of the embedded coupler 16 on the lower surface of the main body. Is done. In this example, the embedded coupler 16 is a screw type having an inner screw hole.

  At the time of connecting the upper and lower blocks 1f, for example, as shown in FIG. 13B, a connecting tool 18 having screws 18a at both ends is used. The upper block 1f is moved downward as indicated by an arrow F, and each screw 18a of the connecting tool 18 is inserted into the embedded coupler 16 on the lower surface of the main body of the upper block 1f and the upper surface of the main body of the lower block 1f. Each of the couplers 16 is screwed and inserted into the hole 16a of each embedded coupler 16. Thereafter, a joint is formed between both blocks 1f.

  Other configurations of the blocks 1e and 1f are substantially the same as those in the first embodiment, and the connection of the left and right blocks is performed in the same manner as in the first embodiment using the coupler 12 and the like. Accordingly, the fifth embodiment can provide the same effects as those of the first embodiment. Also, when the upper and lower blocks are connected by inserting the reinforcing bar 14 and the connecting tool 18 into the hole 16a of the embedded coupler 16 as in the fifth embodiment, the blocks are moved to the left and right as in the first embodiment. Therefore, it is particularly effective to connect the left and right blocks with the coupler 12.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

1, 1a, 1b, 1c, 1d, 1e, 1f, 100; precast block 2; breakwater 3a; inner tub 3b; outer tub 4; pile 5; bottom slab 7: ground 10, 10a, 10b, 10c; Groove 11, 13, 14, 17, 101, 103; rebar 12, 102; coupler 15, 16a; hole 16; embedded coupler 18; connector 18a; screw 20; LNG tank

Claims (6)

It is a connection structure in which a pair of precast blocks are arranged side by side and the reinforcing bars protruding from each of the opposing side surfaces of both precast blocks are connected by a coupler,
Wherein the pair of precast blocks, a horizontal recess provided on the side of the hand of the precast block, the reinforcing bars protrude from the concave portion,
The side surface of the other precast block is a flat surface;
When the concave portion is viewed along the vertical direction, the upper surface is inclined upward from the bottom surface of the concave portion toward the outside of the member,
Filler is filled between the two precast blocks,
The recess, have a inner wall all around,
The connection structure according to claim 1, wherein a protruding length of the reinforcing bar protruding from the recess is larger than a protruding length of the reinforcing bar protruding from the flat surface . Another pair of precast blocks is arranged on the upper or lower stage of the pair of precast blocks,
The other pair of precast blocks are connected by connecting the reinforcing bars protruding from each of the opposing side surfaces of both precast blocks by a coupler, and filling the filler between both precast blocks,
In the upper and lower precast blocks, the reinforcing bars protruding from the lower surface of the upper precast block are inserted into the holes provided on the upper surface of the lower precast block, and between the two precast blocks and between the holes are filled with filler. The connection structure according to claim 1, wherein: Another pair of precast blocks is arranged on the upper or lower stage of the pair of precast blocks,
The other pair of precast blocks are connected by connecting the reinforcing bars protruding from each of the opposing side surfaces of both precast blocks by a coupler, and filling the filler between both precast blocks,
The upper and lower precast blocks are connected to the inner holes of the embedded coupler provided on the lower surface of the upper precast block and the inner holes of the embedded coupler provided on the upper surface of the lower precast block. The connecting structure according to claim 1, wherein each is inserted and filled with a filler between the two precast blocks. The pair of precast blocks and the another pair of precast blocks have different diameters of the reinforcing bars and the couplers,
The connection structure according to claim 2 or 3 , wherein the position of the side surface is aligned between the pair of precast blocks and the another pair of precast blocks. The another pair of precast blocks are also connected by the connection structure according to claim 1,
In the pair of precast blocks and the other pair of precast blocks, the depth of the concave portion with the larger diameter of the reinforcing bar and the longer coupler is the depth of the concave portion with the smaller diameter of the reinforcing bar and the shorter coupler. The connection structure according to claim 4 , wherein the connection structure is larger than the depth of the connection. The rebar protrudes from the left and right sides, and is a precast block provided with a coupler for connection to the reinforcing bar on one side,
The side surface sac Chi hand of the left and right of the precast block, provided a horizontal recess, the reinforcing bars protrude from the concave portion,
The other side is a flat surface,
When the concave portion is viewed along the vertical direction, the upper surface is inclined upward from the bottom surface of the concave portion toward the outside of the member,
The recess, have a inner wall all around,
The precast block characterized in that the protruding length of the reinforcing bar protruding from the recess is larger than the protruding length of the reinforcing bar protruding from the flat surface .

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