CN113266031A - Precast concrete foundation block and joint structure thereof - Google Patents

Abstract

Provided are a precast concrete foundation block and a joint structure thereof, which can freely adjust the position of a screwed flange relative to joint main bars, and can easily form a desired positional relationship between a hollow joint member connecting left and right joint main bars and the screwed flange. A precast concrete foundation block (10) forming a standing part of a foundation, wherein an upper end rib (11) and a part of a longitudinal rib (13) extending in an extending direction of the foundation are embedded in concrete (5), a first recess (17) is provided at a position corresponding to the upper end rib in an end part (16) of the precast concrete foundation block (10) in the extending direction, one end of a joint main rib (20) overlapping the upper end rib by an overlapping joint length in concrete (15) protrudes toward the first recess (17), a thread groove (21) is provided at one end of the joint main rib (20), and a threaded flange (30) is screwed with the thread groove (21).

Description

Precast concrete foundation block and joint structure thereof

Technical Field

The present invention relates to a precast concrete foundation block and a joint structure thereof.

Background

In order to shorten the construction period of a foundation and improve the dimensional accuracy of the foundation in the foundation of a building, the following construction method is applied: the erected portion of the foundation is manufactured as a precast concrete foundation block in a factory, and the precast concrete foundation block is transported to a construction site to be applied to the construction of the foundation. The plurality of precast concrete foundation blocks transported to the construction site are laid in the extending direction of the foundation, and the foundation is constructed on site below the rising portion formed by the precast concrete foundation blocks so as to be integrated with the rising portion, whereby the construction period of the foundation such as a strip-shaped foundation can be significantly shortened.

As for the precast concrete foundation block, the following precast concrete foundation blocks are proposed: a male joining metal fitting is provided at both ends or one end; a female joint metal fitting provided at both ends or at one end; alternatively, a male joint metal fitting is provided at one end portion and a female joint metal fitting is provided at the other end portion (see, for example, patent document 1).

However, the block disclosed in patent document 1 has a problem that the construction process is fixed. That is, since the adjacent precast concrete foundations are coupled to each other by the coupling members of the male and female coupling metal members, it is necessary to first arrange the precast concrete foundation having the female coupling metal member, and then to fit the precast concrete foundation having the male coupling metal member to the female coupling metal member of the previously arranged precast concrete foundation. Further, since a male type joint metal fitting and a female type joint metal fitting are required, there are problems that the number of types of metal fittings increases, the cost increases, and the production efficiency decreases.

In order to solve these problems, a joining structure is proposed which includes: a first recess and a second recess for grouting material filling, which are formed at positions where foundations are joined to each other; and a tendon having a rod-shaped body connected to the upper end tendon, wherein a distal end side of the tendon is exposed into the first concave portion, a convex portion protruding from the rod-shaped body is formed on the distal end side of the tendon, and the convex portions are connected to each other by a joint member having a fitting portion fitted into both the convex portions. According to this joint structure, since the projecting portions are present on the distal ends of the facing anchor bars of the joined precast concrete foundations and there is no male-female relationship, the order of installing the foundations is not fixed (see, for example, patent document 2).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-227787

Patent document 2: japanese patent laid-open publication No. 2017-066598

Patent document 2 describes the following: the convex portion is integrally formed on the rod-like body of the anchor bar by forging. However, when the convex portion is integrally formed on the rod-shaped body of the anchor by forging, it is difficult to ensure the dimensional accuracy of the convex portion. Further, when the joint members are dropped from above the projecting portions at both ends of the anchor bars extending from the left and right precast concrete foundation blocks on the site and both the projecting portions are fitted into the fitting portions of the joint members, the projecting portions are fixed to the ends of the anchor bars, and therefore, it is difficult to adjust the positions of the projecting portions in the longitudinal direction of the anchor bars.

Further, after the left and right convex portions are accommodated in the fitting portions of the joint member, a grouting material is filled in the first concave portion and the second concave portion. Preferably, the convex portion is brought into close contact with the inner end surface of the joint member to make the gap zero, or a gap of several millimeters or less into which a grouting material can enter is provided between the convex portion and the inner end surface of the joint member. However, it is extremely difficult to accommodate the convex portion in the fitting portion of the joint member in a state where the convex portion is in close contact with the inner end surface of the joint member, or to accommodate the convex portion in the fitting portion of the joint member with a gap of several millimeters or less.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide a precast concrete foundation block and a joint structure based on the precast concrete foundation block, in which a position of a member corresponding to the convex portion can be easily adjusted with respect to a member corresponding to the anchor bar, and a dimensional accuracy of the member corresponding to the convex portion is high, in the precast concrete foundation block forming a standing portion of a foundation.

In order to achieve the above object, one aspect of the precast concrete foundation block of the present invention is a precast concrete foundation block forming a rising portion of a foundation, the precast concrete foundation block characterized in that,

the precast concrete foundation block has: an upper end rib and a lower end rib extending in the extending direction of the foundation; and a longitudinal bar connecting the upper end bar and the lower end bar in the vertical direction, a part of the upper end bar and the longitudinal bar being embedded in concrete,

a first concave portion is provided in a position corresponding to the upper end rib in an end portion of the precast concrete foundation block in the extending direction,

one end of a joint main bar overlapping with the upper end bar by an overlapping joint length in the concrete protrudes toward the first recess,

a screw groove is provided at the one end of the joint main rib, and a screwed flange is screwed with the screw groove.

According to the present invention, since the threaded groove is provided at one end of the joint main rib that overlaps the upper end rib by the overlapping joint length, and the screwed flange is screwed into the threaded groove, the position of the screwed flange can be freely adjusted with respect to the joint main rib. Therefore, even when the positional relationship between the two precast concrete foundation blocks, the screwed flanges screwed to the joint main ribs protruding into the first recesses of both sides, and the joining member connecting them is not in the desired positional relationship at the site, the positional adjustment is realized by rotating the screwed flanges with respect to the joint main ribs, and the joining member and the screwed flanges can be easily set in the desired positional relationship at the site. That is, the screwed flange can be easily brought into close contact with the joining member by rotating and relatively moving the screwed flange with respect to the joint main rib, and the positional relationship between the joining member and the screwed flange can be established so that a gap of a degree that the grouting material can be filled is provided therebetween. Here, the flange to be screwed may be a nut. The dimensional accuracy of the nut is significantly improved as compared with the above-described convex portion formed by forging.

Further, an aspect of the joint structure of the precast concrete foundation blocks of the present invention is characterized in that,

the end portions of the two precast concrete foundation blocks abut against each other, and the first concave portions of both are continuous, thereby forming a second concave portion,

the end portion of the joint main rib extending from the left and right sides is inserted into the insertion hole of the hollow joint member having the insertion hole at the left and right ends, the screwed flange disposed in the hollow portion of the joint member is screwed to the end portion of the joint main rib, and the hollow portion and the second concave portion are filled with a grouting material.

According to the present invention, the hollow joint member disposed in the second recess formed by the first recesses of the two precast concrete foundation blocks can be adjusted to a desired positional relationship with the screwed flange while moving the screwed flange at the end portions of the joint main ribs extending from the left and right sides and located inside the hollow joint member.

In addition, another aspect of the joining structure of precast concrete foundation blocks according to the present invention is characterized in that a gap is provided between the inner wall surface of the hollow portion of the joining member and the screwed flange, and the grouting material is filled and cured in the gap.

According to this aspect, by desirably moving the screwed flange, a predetermined gap into which a grouting material can be filled is formed between the inner wall surface of the hollow portion of the joining member and the screwed flange. Therefore, for example, a series of axial force transmission is effectively performed in which the axial force transmitted through the upper end reinforcement and the joint main reinforcement of one of the left and right precast concrete foundation blocks is transmitted to the joint member by the grouting material filled and cured in the gap, and transmitted to the joint main reinforcement and the upper end reinforcement of the other of the left and right precast concrete foundation blocks through the joint member.

In addition, in another aspect of the joining structure of the precast concrete foundation block according to the present invention, an inner wall surface of the hollow portion of the joining member is in close contact with the screwed flange.

According to this aspect, the screwed flange can be moved as desired, whereby the inner wall surface of the hollow portion of the joining member can be brought into close contact with the screwed flange completely. Therefore, in this aspect, the above-described series of axial force transmission can be efficiently performed.

In addition, in other aspects of the joining structure of a precast concrete foundation block of the present invention, characterized in that the joining member has an opening communicating with the hollow portion,

the opening is an insertion opening for inserting the screwed flange into the hollow portion, and is an adjustment opening for screwing the screwed flange to an end portion of the joint main rib and adjusting a position of the screwed flange.

According to the present invention, since the joining member has the opening communicating with the hollow portion, the screwed flange can be inserted into the hollow portion through the opening, and the screwed flange can be moved within the hollow portion at the end portion of the joint main rib to precisely adjust the position.

Effects of the invention

As can be understood from the above description, according to the precast concrete foundation block and the joining structure thereof of the present invention, the position of the screwed flange can be freely adjusted with respect to the joint main bars, and a desired positional relationship between the screwed flange and the hollow joining member connecting the left and right joint main bars can be easily formed.

Drawings

Fig. 1 is a longitudinal sectional view of one example of the precast concrete foundation block of the embodiment.

Fig. 2 is a view in the direction of an arrow II-II of fig. 1, and is a longitudinal sectional view orthogonal to fig. 1.

Fig. 3 is a longitudinal sectional view showing an example of a joint structure of precast concrete foundation blocks of the embodiment, and is a view showing a band-shaped foundation formed of a precast concrete foundation and a site construction foundation together.

Fig. 4 is a view in the direction of the arrows IV-IV of fig. 3.

Fig. 5 is a view in the direction of the V-V arrow of fig. 4.

Fig. 6 is a perspective view of an example of the joint member, and is a view for explaining a state in which the end portion of the joint main rib is inserted into the hollow portion of the joint member and the screwed flange is inserted into the hollow portion through the opening.

Fig. 7 is a diagram for explaining an example of position adjustment of the screwed flange in the hollow portion of the joining member and showing a positional relationship between the inner wall surface of the hollow portion of the joining member and the screwed flange.

Fig. 8 is a view illustrating a state in which a grouting material is filled and cured in the second concave portion in the positional relationship between the joining member and the screwed flange shown in fig. 7.

Fig. 9 is a diagram for explaining another example of the positional adjustment of the screwed flange in the hollow portion of the joining member and showing the positional relationship between the inner wall surface of the hollow portion of the joining member and the screwed flange.

Fig. 10 is a view illustrating a state in which a grouting material is filled and cured in the second concave portion in the positional relationship between the joining member and the screwed flange shown in fig. 9.

Description of the reference symbols

10: prefabricating a concrete foundation block; 11: an upper end rib; 12: a lower end rib; 13: longitudinal bars (stirrups); 14: transverse (abdominal) tendons; 15: precast concrete (concrete); 17: a first recess; 18: a third recess; 20: a joint main rib; 21: a thread groove; 30: a screwed flange (nut); 40: a second recess; 50: a fourth recess; 60: a joint main rib; 70: an engaging member; 71: a main body; 72: a hollow part; 73: an opening; 74: an inner wall surface (inner wall surface) of the hollow portion; 75: a through insertion hole; 80: grouting material; 90: a footing; 100: a joint structure of precast concrete foundation blocks (joint structure); 200: and (4) banding foundation.

Detailed Description

The precast concrete foundation block and the joint structure thereof according to the embodiment of the present invention will be described below with reference to the accompanying drawings. In the present specification and the drawings, the same reference numerals are used to designate substantially the same components, and redundant description thereof may be omitted.

[ precast concrete foundation block of embodiment ]

First, a precast concrete foundation block according to an embodiment will be described with reference to fig. 1 and 2. Here, fig. 1 is a longitudinal sectional view of an example of the precast concrete foundation block of the embodiment, and fig. 2 is a view in a direction of an arrow II-II of fig. 1, and is a longitudinal sectional view orthogonal to fig. 1.

The illustrated precast concrete foundation block 10 is a precast concrete foundation block forming a standing part of a foundation, and is manufactured in a factory, transported to a site, and formed into a foundation such as a strip foundation. As shown in fig. 1, the precast concrete foundation block 10 has: an upper end rib 11 and a lower end rib 12 extending in an extending direction of the foundation, i.e., the L direction; a plurality of longitudinal beads 13 (stirrups) which connect the upper end bead 11 and the lower end bead 12 in the vertical direction and are arranged at a predetermined pitch in the L direction; and a transverse rib 14 (web rib) extending in the L direction between the upper end rib 11 and the lower end rib 12. The upper end bar 11, the horizontal bar 14, and the vertical bar 13 are partially embedded in precast concrete 15, and the lower end bar 12 embedded in concrete for footing cast in place is exposed to the outside to constitute an integral structure.

As shown in fig. 2, the upper end bead 11, the lower end bead 12, the longitudinal bead 13, and the like are arranged at substantially the center of the cross section (cross section in the direction orthogonal to the longitudinal direction) of the precast concrete foundation block 10. In fig. 1, the left side of the precast concrete 15 is not shown, and the left end of the precast concrete 15 has, for example, the same structure as the right end shown in the drawing.

A first recess 17 (detent) having a rectangular parallelepiped shape is provided at a position corresponding to the upper end rib 11 in an end portion 16 of the precast concrete foundation block 10 in the extending direction. Further, at the end portion 16, a plurality of (three in the illustrated example) third concave portions 18 having a trapezoidal columnar shape are provided at intervals at a position below the first concave portion 17, the first concave portion 17 and each of the third concave portions 18 communicate with each other through a communication groove (not illustrated) formed at the end portion 16, and the grouting material filled in the first concave portion 17 sequentially flows into each of the third concave portions 18 through the communication groove.

A joint main rib 20 overlapping the upper end rib 11 by an overlapping joint length t1 is also embedded in the precast concrete 15, and an end of the upper end rib 11 and an end of the joint main rib 20 protrude toward the first concave portion 17.

A screw groove 21 is provided at one end of the joint main rib 20 protruding toward the first recess 17, and a screwed flange 30 is screwed into the screw groove 21. As an example of the screwed flange 30, a nut with high dimensional accuracy is cited.

A plurality of precast concrete foundation blocks 10 manufactured in a factory are transported to a site and arranged in an extending direction of a foundation along an outer wall of a building, thereby forming, for example, a standing portion of a strip-shaped foundation.

[ Joint Structure of precast concrete Foundation Block of embodiment ]

Next, a joint structure of the precast concrete foundation blocks according to the embodiment will be described with reference to fig. 3 to 10. Here, fig. 3 is a longitudinal sectional view showing an example of a joint structure of precast concrete foundation blocks of the embodiment, and is a view showing a band-shaped foundation formed of a precast concrete foundation and a site construction foundation together. Further, fig. 4 is a view in the direction of the arrow IV-IV of fig. 3, and fig. 5 is a view in the direction of the arrow V-V of fig. 4.

As shown in fig. 3 and 4, the end portions 16 of the precast concrete foundation blocks 10 connected to each other are brought into contact with each other, whereby both the first concave portions 17 are continued to form the second concave portion 40. Similarly, the third recesses 18 of both are continuous to form a plurality of fourth recesses 50.

The ends of the left and right joint main ribs 20 having the screw grooves 21 project into the second recess 40, and the screwed flanges 30 are screwed into the respective screw grooves 21. The left and right screwed flanges 30 are positioned in the joining member 70 having a hollow portion, and the second recess 40 is filled with a grouting material 80 such as shrinkage-free mortar and the like so as to embed the joining member 70 or the screwed flanges 30. The grouting material 80 filled in the second recess 40 sequentially flows into the plurality of fourth recesses 50 located below the second recess 40 to be cured, so that substantially the entire faces of the end portions 16 of the two precast concrete foundation blocks are joined by the grouting material 80, forming the joint structure 100 of the precast concrete foundation blocks.

At a construction site, a plurality of precast concrete foundation blocks are joined by a joint structure 100 along an extension setting direction of the foundation, and form a rising portion of a strip-shaped foundation. Further, after the joint main reinforcements 60 that overlap the joint length with the lower end reinforcements 12 of both the adjacent precast concrete foundation blocks 10 are arranged, the concrete for footing shown by the two-dot chain lines in fig. 3 to 5 is poured on site so that the lower end reinforcements 12 and the joint main reinforcements 60 are wound in. Through the series of works, the strip-shaped foundation 200 is constructed in which the standing part formed by the plurality of precast concrete foundation blocks 10 and the footing 90 formed in the on-site work are integrated.

Next, an example of the engaging member will be described with reference to fig. 6. Here, fig. 6 is a perspective view of an example of the joint member, and is a view explaining a state in which the end portion of the joint bead is inserted into the hollow portion of the joint member and the screwed flange is inserted into the hollow portion through the opening.

The joining member 70 has a substantially cylindrical main body 71 made of metal or hard resin, and a hollow portion 72 is provided in the center of the main body. Through-insertion holes 75 (only one through-insertion hole 75 is shown in fig. 6) through which the end portions of the joint main ribs 20 are inserted are opened at both ends of the main body 71, and each through-insertion hole 75 communicates with the hollow portion 72. A pair of openings 73 are opened in the upper and lower positions of the side surface of the main body 71, and the openings 73 also communicate with the hollow portion 72. The opening 73 has the following degrees of area: the screwed flange 30 held by fingers of an operator can be inserted into the hollow portion 72, and the screwed flange 30 can be rotated relative to the screw groove 21 of the joint main rib 20 protruding into the hollow portion 72 to adjust the position thereof. That is, the opening 73 has a function of an insertion port for inserting the screwed flange 30 into the hollow portion 72, and also has a function of an adjustment port for adjusting the position of the screwed flange 30. Further, the through insertion hole 75 faces a pair of inner wall surfaces 74 of the main body 71 facing the hollow portion 72.

As shown in fig. 6, after the end portion of the joint main rib 20 is inserted into the insertion hole 75 along the X1 direction and the screw groove 21 is projected into the hollow portion 72, the screwed flange 30 is inserted into the hollow portion 72 through the opening 73, the screwed flange 30 is screwed into the screw groove 21, the screwed flange 30 is moved to a desired position, and the screwed flange 30 is set at a desired position with respect to the joint main rib 20 whose end portion is inserted into the joining member 70.

Although not shown, the temporary installation of the joint main bead 20 on the left side and the screwed flange 30 to the joint member is achieved in the above-described procedure in the first concave portion 17 of, for example, the precast concrete foundation block 10 on the left side before the two precast concrete foundation blocks 10 in fig. 3 and 4 are joined.

Next, as shown in fig. 3 and 4, the right precast concrete foundation block 10 is brought into contact with the left precast concrete foundation block 10, and the two first recesses 17 are continued to form the second recess 40. In the second recess 40, the joint member 70, on which the left joint main bar 20 and the screwed flange 30 are temporarily provided, is moved to the left, and the end portion of the joint main bar 20 of the right precast concrete foundation block 10 is inserted into the hollow portion 72 through the other insertion hole 75 of the joint member 70. Further, the screwed flange 30 is inserted into the hollow portion 72 of the joining member 70 through the opening 73 in the same manner as the method shown in fig. 6, and the screwed flange 30 is screwed into the thread groove 21 at the end portion of the right joint main rib 20, thereby achieving temporary setting of the right joint main rib 20 and the screwed flange 30 to the joining member 70.

After the temporary setting of the left and right joint main ribs 20 and the screwed flanges 30 with respect to the joining member 70 is achieved, the joining member 70 is positioned, for example, near the center position of the second recess 40, and the screwed flanges 30 are rotated and moved again with respect to the left and right joint main ribs 20 in the hollow portion 72 of the joining member 70, whereby the position of the left and right screwed flanges 30 can be adjusted.

Next, an example of the positional relationship between the inner wall surface 74 of the hollow portion 72 of the engaging member 70 and the screwed flange 30 will be described with reference to fig. 7 to 10. Here, fig. 7 is a diagram illustrating an example of the positional adjustment of the screwed flange in the hollow portion of the joining member and showing the positional relationship between the inner wall surface of the hollow portion of the joining member and the screwed flange. Fig. 8 is a view illustrating a state in which a grouting material is filled and cured in the second concave portion in the positional relationship between the joining member and the screwed flange shown in fig. 7. Fig. 9 and 10 are diagrams corresponding to fig. 7 and 8, respectively, and are diagrams showing other examples of the positional relationship.

As shown in fig. 7, the screw grooves 21 at the end portions of the joint main ribs 20 project from the left and right into the hollow portion 72 of the joining member 70 disposed in the second recess 40, and the screwed flange 30 is moved in the X3 direction by rotating the screwed flange 30 with respect to each screw groove 21 with a finger or the like, whereby the screwed flange 30 can be positioned at a desired position with respect to the joining member 70.

The example shown in fig. 7 is a form in which the inner wall surface 74 facing the hollow portion 72 and the screwed flange 30 are in close contact with each other. After the inner wall surface 74 is brought into close contact with the screwed flange 30 in this way, the grouting material 80 is filled and solidified in the second recess 40 as shown in fig. 8, thereby forming the connection structure 100.

Fig. 8 shows a simulation in which a tensile force N (or an axial force N) acts from the upper end reinforcement 11 of the left precast concrete foundation block 10 via the joint main reinforcement 20. The tensile force N acting on the left joint bead 20 is distributed into a plurality of component forces N1 via the screwed flange 30 and transmitted to the joining member 70 where the screwed flange 30 is in close contact with the inner wall surface 74, and then each component force N1 is transmitted to the right screwed flange 30 where the right inner wall surface 74 is in close contact with via the joining member 70. Further, the resultant force of the component forces N1, i.e., the tensile force N, is transmitted to the right joint main bead 20 and to the upper end bead 11 of the right precast concrete foundation block 10. In this way, the inner wall surface 74 of the joining member 70 and the screwed flange 30 are in close contact with each other, and thereby the tensile force N between the adjacent precast concrete foundation blocks 10 is effectively transmitted.

On the other hand, the example shown in fig. 9 is a form in which the screwed flange 30 is moved in the X3 direction while the screwed flange 30 is turned by a finger or the like, and a gap G having a predetermined width t2 is formed between the inner wall surface 74 of the joining member 70 and the screwed flange 30. The predetermined width t2 is a width of about 1 mm to several mm and capable of being filled with a grouting material.

After the screwed flange 30 is positioned between the inner wall surface 74 and the screwed flange 30 so as to have the gap G of the predetermined width t2, the grouting material 80 is filled and solidified in the second recess 40 as shown in fig. 10, thereby forming the connection structure 100.

In the connection structure 100 shown in fig. 10, the grouting material 80 sufficiently enters into the gap G to be cured. Therefore, when a tensile force N acts from the right side as in fig. 8, the tensile force N is distributed from the screwed flange 30 to the joint member 70 via the solidified grouting material 80 interposed in the gap G into a plurality of component forces N1. Then, the component forces N1 are transmitted to the right screwed flange 30 via the joint member 70 via the cured grouting material 80 interposed in the gap G, and the tensile force N, which is the resultant force of the component forces N1, is transmitted to the right joint main bead 20.

In this way, in the joint structure 100 of either of fig. 8 and 10, the axial force acting on the upper end rib 11 of one of the adjacent precast concrete foundation blocks 10 can be efficiently transmitted to the upper end rib 11 of the other precast concrete foundation block 10, and the external force acting can be resisted by the plurality of precast concrete foundation blocks 10 integrated by the connecting structure 100.

The present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with each other. In this regard, modifications can be made without departing from the scope of the present invention, and it can be determined appropriately according to the application form.

For example, the joint member 70 shown in the drawing is configured to insert the end portion of the joint main rib 20 into the hollow portion 72 through the pair of insertion holes 75 and to insert the threaded flange 30 into the hollow portion 72 through the opening 73 to be threaded into the threaded groove 21, but may be configured in other forms. For example, the following configuration is also possible: the joining member has a fitting opening continuous with the hollow portion thereof at the lower portion of the body, and by dropping the joining member from above, the end portions of the left and right joint main ribs 20 and the screwed flanges 30 screwed into the screw grooves 21 thereof are fitted into the opening at one time through the fitting opening.

Claims (5)

1. A precast concrete foundation block forming a rising portion of a foundation, characterized in that,

the precast concrete foundation block has: an upper end rib and a lower end rib extending in the extending direction of the foundation; and a longitudinal bar connecting the upper end bar and the lower end bar in the vertical direction, a part of the upper end bar and the longitudinal bar being embedded in concrete,

a first concave portion is provided in a position corresponding to the upper end rib in an end portion of the precast concrete foundation block in the extending direction,

one end of a joint main bar overlapping with the upper end bar by an overlapping joint length in the concrete protrudes toward the first recess,

a screw groove is provided at the one end of the joint main rib, and a screwed flange is screwed with the screw groove.

2. A joint structure of precast concrete foundation blocks, characterized in that,

the precast concrete foundation block of two claims 1, wherein the end portions abut each other, the first recesses of both being continuous, thereby forming a second recess,

the end portion of the joint main rib extending in the left-right direction is inserted into the insertion hole of the hollow joint member having insertion holes at the left and right ends, the screwed flange disposed in the hollow portion of the joint member is screwed to the end portion of the joint main rib, and the hollow portion and the second concave portion are filled with a cured grouting material.

3. The joining structure of precast concrete foundation blocks according to claim 2,

a gap is provided between the inner wall surface of the hollow portion of the joining member and the screwed flange, and the gap is filled with the grouting material.

4. The joining structure of precast concrete foundation blocks according to claim 2,

the inner wall surface of the hollow portion of the joining member is in close contact with the screwed flange.

5. The precast concrete foundation block joining structure according to any one of claims 2 to 4,

the engaging member has an opening communicating with the hollow portion,

the opening is an insertion opening for inserting the screwed flange into the hollow portion, and is an adjustment opening for screwing the screwed flange to an end portion of the joint main rib and adjusting a position of the screwed flange.

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