JP2021123961A - Construction method of pile head part reinforcement structure, and mold - Google Patents

Abstract

To provide a rational construction method of a pile head part reinforcement structure of a foundation pile installed into the ground.SOLUTION: A method for connecting a foundation pile 2 installed into the ground and a foundation structure (for example, foundation slab 4) constructed above a pile head part of the foundation pile 2, and constructing a pile head part reinforcement structure 3 for reinforcing the pile head part of the foundation pile 2 includes: an excavation recess formation step (S2) of excavating ground G so as to expose the pile head part of the foundation pile 2, and thereby forming an excavation recess 20 in the ground G; a first mold installation step (S4) of installing a first cylindrical mold 10 on a bottom surface 20a of the excavation recess 20 so as to surround the periphery of the pile head part of the exposed foundation pile 2; and a concrete installation step (S8) of installing concrete 15 into the first mold 10. The first mold 10 is made of precast concrete. The pile head part reinforcement structure 3 includes the first mold 10, and the concrete 15 installed into the first mold 10.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method for constructing a pile head reinforcing structure for reinforcing the pile head of a foundation pile placed in the ground, and a formwork used for constructing the pile head reinforcing structure.

Patent Document 1 discloses a pile head reinforcing structure for reinforcing the pile head inserted in the lower part of the footing. The first aspect of the pile head reinforcement structure in Patent Document 1 is that a pile head reinforcement unit formed by assembling a peripheral bar, a stirrup, and a footing integral bar is installed on the pile head portion. The second aspect of the pile head reinforcement structure in Patent Document 1 is a precast concrete pile head reinforcement unit in which a footing integral bar protrudes upward is installed in the pile head portion.

Japanese Patent No. 2891167

However, in the first aspect of the pile head reinforcement structure in Patent Document 1, concrete is cast in place at the installation location of the pile head reinforcement unit made of reinforcing bars. For this reason, it is necessary to install the formwork, place concrete, cure, and remove the formwork at the installation location of the pile head reinforcement unit, which takes time for construction.
Further, in the second aspect of the pile head reinforcement structure in Patent Document 1, when the size of the precast concrete pile head reinforcement unit is increased, it takes time and effort to transport and install the precast concrete pile head reinforcement unit.

In view of such an actual situation, the present invention relates to a more rational construction method of a pile head reinforcement structure for reinforcing the pile head of a foundation pile placed underground, and a mold that can be used for this construction. The challenge is to provide a frame.

Therefore, in the method for constructing the pile head reinforcement structure according to the present invention, the foundation pile placed in the ground and the foundation structure constructed above the pile head of the foundation pile are connected and the pile head is constructed. This is a method of constructing a pile head reinforcement structure that reinforces the part. The method for constructing the pile head reinforcement structure according to the present invention includes an excavation recess forming step of forming an excavation recess in the ground by excavating the ground so as to expose the pile head, and surrounding the exposed pile head. The first formwork installation step of installing the tubular first formwork on the bottom surface of the excavation recess and the concrete placing step of placing concrete in the first formwork are included. The first formwork is made of precast concrete. The pile head reinforcement structure includes a first formwork and concrete placed in the first formwork.

The formwork according to the present invention is a formwork used for reinforcing the pile head of a foundation pile placed underground. The formwork according to the present invention has a main body portion that is tubular and is made of precast concrete that extends in the vertical direction, a first reinforcing bar that is embedded in the main body portion and extends in the circumferential direction of the main body portion, and a part of the main body. It is provided with a second reinforcing bar that is embedded in the portion and the remaining portion is exposed in the internal space of the main body portion. Here, the pile head is inserted into the internal space and concrete is poured.

According to the present invention, the formwork (first formwork) used for reinforcing the pile head is made of tubular precast concrete. Therefore, after the concrete is cast in the formwork, the formwork can be left without being removed and used as the outer shell of the pile head reinforcing structure. Further, since the formwork has a tubular shape, it is clearly lighter than the pile head reinforcing structure composed of a solid type precast member. Therefore, the labor of transportation and installation can be reduced. Therefore, it is possible to rationalize the construction of the pile head reinforcement structure.

The figure which shows the schematic structure of the foundation in 1st Embodiment of this invention. The figure which shows the schematic structure of the 1st formwork in said 1st Embodiment A flowchart showing a method of constructing a foundation in the first embodiment. The figure which shows the method of constructing the foundation in the said 1st Embodiment The figure which shows the method of constructing the foundation in the said 1st Embodiment The figure which shows the method of constructing the foundation in the said 1st Embodiment The figure which shows the method of constructing the foundation in the said 1st Embodiment The figure which shows the method of constructing the foundation in the said 1st Embodiment The figure which shows the schematic structure of the foundation in 2nd Embodiment of this invention.

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

FIG. 1 is a diagram showing a schematic configuration of a foundation 1 according to the first embodiment of the present invention. Specifically, FIG. 1A is a vertical cross-sectional view of the foundation 1, and FIG. 1B is a top view of the foundation 1. In FIGS. 1 (a) and 1 (b), the first to third reinforcing bars 11 to 13, the pile head reinforcing bars 17, and the reinforcing bars 22, which will be described later, are omitted for simplification of the illustration.

The foundation 1 is, for example, an equipment foundation installed in a factory. The foundation 1 in the present embodiment includes a plurality of foundation piles 2, a plurality of pile head reinforcement structures 3 separately constructed on the pile heads (upper ends) of each foundation pile 2, and these pile head reinforcement structures 3. It is configured to include the foundation slab 4 constructed above. Here, the foundation slab 4 is an example of the "foundation structure" of the present invention, and is constructed above the pile head of the foundation pile 2.

In the present embodiment, the foundation pile 2 and the pile head reinforcing structure 3 constituting the foundation 1 are located in the ground (in the ground G), and at least the lower part of the foundation slab 4 is located in the ground. That is, in the present embodiment, at least the lower part of the foundation slab 4, the pile head reinforcing structure 3, and the foundation pile 2 are located below the ground GS.

The foundation pile 2 is made of, for example, concrete or steel. In the present embodiment, the foundation pile 2 will be described below as a PHC pile, but the foundation pile 2 is not limited to the PHC pile and may be a well-known pile (for example, a steel pipe pile) other than the PHC pile.

In the present embodiment, the foundation pile 2 is driven into the ground and extends in the vertical direction. In the arrangement shown in FIG. 1 (a), 16 foundation piles 2 are arranged in a matrix (4 × 4 in the figure) in parallel with each other in a plan view. The number and arrangement of the foundation piles 2 constituting the foundation 1 are not limited to those shown in FIG.

The pile head reinforcement structure 3 connects the foundation pile 2 and the foundation slab 4, and also reinforces the pile head of the foundation pile 2. The pile head reinforcing structure 3 includes a first formwork 10, concrete 15 cast in the first formwork 10, and a plurality of pile head reinforcing bars 17 (see FIG. 8). Details of the first formwork 10 will be described later with reference to FIG.

In the present embodiment, the foundation slab 4 has a thick plate shape extending horizontally and a rectangular shape in a plan view. However, the shape of the foundation slab 4 is not limited to this. The foundation slab 4 is made of concrete (made of reinforced concrete (made of RC)) including the reinforcing bar 22 (see FIG. 8) described later.
As shown in FIG. 1A, the foundation pile 2 and the pile head reinforcing structure 3 are arranged so as to be included in the foundation slab 4 in a plan view.

FIG. 2 is a diagram showing a schematic configuration of the first mold 10. Specifically, FIG. 2A is a vertical cross-sectional view of the first formwork 10, and corresponds to the BB cross section of FIG. 2B. FIG. 2A is a cross-sectional view of the first formwork 10, and corresponds to the AA cross section of FIG. 2A.

The first formwork 10 is a formwork used for reinforcing the pile head of the foundation pile 2 placed in the ground. The first formwork 10 includes a tubular main body portion 10a, a plurality of first reinforcing bars (outer peripheral reinforcing bars) 11, a plurality of second reinforcing bars (internal reinforcing bars) 12, and a plurality of third reinforcing bars (connecting portion reinforcing bars). 13 and. That is, the first formwork 10 has a tubular shape and has a first reinforcing bar 11, a second reinforcing bar 12, and a third reinforcing bar 13.

The first formwork 10 (specifically, the main body 10a) is made of precast concrete. In the present embodiment, the first mold 10 (specifically, the main body portion 10a) has a cylindrical shape extending in the vertical direction and has a rectangular cross section. However, the cross-sectional shape of the first mold 10 (specifically, the main body portion 10a) is not limited to a rectangle, and may be, for example, a circle. The upper surface and the lower surface of the first mold 10 (specifically, the main body 10a) are open.

The pile head of the foundation pile 2 can be inserted into the internal space (space surrounded by the inner peripheral surface of the main body 10a) 10b of the first formwork 10. Further, concrete 15 can be cast in the internal space 10b. The wall thickness of the main body 10a is, for example, in the range of 15 cm to 20 cm.

The first reinforcing bar 11 is embedded in the main body portion 10a and extends in the circumferential direction of the main body portion 10a. The first reinforcing bar 11 is an annular shape that follows the cross-sectional shape of the first mold 10 (specifically, the main body portion 10a). Therefore, in the present embodiment, the first reinforcing bar 11 is a rectangular ring. The plurality of first reinforcing bars 11 constituting the first formwork 10 are arranged at intervals in the vertical direction. FIG. 2A shows an example in which the three first reinforcing bars 11 are arranged in the vertical direction at intervals from each other, but the number of the first reinforcing bars 11 constituting the first formwork 10 is three. The number is not limited and may be any number.

The plurality of second reinforcing bars 12 constituting the first formwork 10 are arranged in a well shape in a plan view. The second reinforcing bar 12 extends linearly in the horizontal direction, both ends thereof are embedded in the main body portion 10a, and the other portions are exposed in the internal space 10b of the main body portion 10a. That is, a part (for example, both ends) of the second reinforcing bar 12 is embedded in the main body portion 10a, and the remaining portion (for example, a portion other than both ends) is exposed in the internal space 10b of the main body portion 10a. Regarding the portion of the second reinforcing bar 12 exposed to the internal space 10b, when the pile head of the foundation pile 2 is inserted into the internal space 10b, the pile head of the foundation pile 2 and / or the pile head reinforcing bar 17 It is placed in a position to dodge.

The third reinforcing bar 13 extends linearly in the vertical direction. The third reinforcing bar 13 extends upward from the upper end portion of the main body portion 10a. The third reinforcing bar 13 is a reinforcing bar for connecting the pile head reinforcing structure 3 and the foundation slab 4.

Therefore, the first formwork 10 is a precast formwork made of reinforced concrete (made of RC).
Here, the first reinforcing bar 11, the second reinforcing bar 12, and the third reinforcing bar 13 are substantially all of the reinforcing bars constituting the pile head reinforcing structure 3, and the first formwork 10 is used when the first formwork 10 is manufactured. It is to be incorporated.
Further, the third reinforcing bar 13 (reinforcing bar for connecting the pile head reinforcing structure 3 and the foundation slab 4) can be installed in the first formwork 10 at the time of manufacturing the first formwork 10.

The first formwork 10 functions as a buried formwork (in other words, a remaining formwork) at the time of construction of the pile head reinforcing structure 3. Therefore, the outer peripheral dimension of the first formwork 10 (specifically, the main body portion 10a) substantially matches the outer peripheral dimension of the pile head reinforcing structure 3. Therefore, the first formwork 10 forms the outer shell of the pile head reinforcing structure 3.

At the time of manufacturing the first formwork 10, it is preferable to use a general formwork such as metal foam on the outer surface and an embedded formwork (in other words, a residual formwork) such as punching foam (registered trademark) on the inner surface. As a result, it is possible to eliminate the need to remove the inner formwork when manufacturing the first formwork 10, so that the manufacture of the first formwork 10 can be facilitated.
When manufacturing the first mold 10, a general mold such as metal foam may be used on both the outer surface and the inner surface. Alternatively, when manufacturing the first formwork 10, an embedded formwork (in other words, a remaining formwork) such as punching foam (registered trademark) may be used on both the outer surface and the inner surface.

Since the first mold 10 does not require dimensional accuracy as in the shield tunnel segment, a mold is not required at the time of manufacturing, and a general mold or the like can be manufactured easily and at low cost. Further, regarding the manufacturing location of the first formwork 10, without being particular about manufacturing in a factory away from the construction site, for example, at the construction site, in step S4 (first formwork installation process) of FIG. 3 described later. It may be manufactured in advance.

Next, the method of constructing the foundation 1 in the present embodiment will be described with reference to FIGS. 3 to 8 in addition to FIGS. 1 and 2 described above.
FIG. 3 is a flowchart showing a method of constructing the foundation 1 in the present embodiment. 4 to 8 are diagrams showing a method of constructing the foundation 1 in the present embodiment.
Here, the method of constructing the foundation 1 shown in FIGS. 3 to 8 includes a method of constructing the pile head reinforcing structure 3.

In the construction of the foundation 1, first, in step S1 (foundation pile driving process), the pile head of the foundation pile 2 is made of yatko (steel) so that the height of the pile head of the foundation pile 2 becomes the design height. (Temporary pile) 6 is attached, and the foundation pile 2 is driven into the ground (in the ground G) (see FIG. 4 (a)). After the foundation pile 2 has been driven into the ground, the yatko 6 is removed.

Next, in step S2 (excavation recess forming step), the excavation recess 20 is formed in the ground G by excavating the ground G downward from the ground GS side so as to expose the pile head of the foundation pile 2 (FIG. 4 (a)).

Next, a crushed stone layer (not shown) is installed on the bottom surface 20a of the excavation recess 20 near the pile head of the foundation pile 2 where the pile head reinforcing structure 3 is constructed, and further on the crushed stone layer (not shown). Perform leveling concrete (not shown) (first crushed stone layer installation / leveling concrete construction process). Here, the height of the bottom surface 20a of the excavation recess 20 in step S2 described above so that the height of the upper surface of the leveling concrete constructed in this step substantially matches the design height of the lower surface of the pile head reinforcing structure 3. Is adjusted accordingly.

Next, in step S3 (pile head reinforcing bar installation step), a plurality of pile head reinforcing bars 17 are installed on the pile head of the foundation pile 2 (see FIG. 5 (c)). The pile head reinforcing bar 17 is a reinforcing bar extending upward from the pile head of the foundation pile 2. When the foundation pile 2 is a PHC pile as in the present embodiment, for example, an NCP anchor (registered trademark) can be used as the pile head reinforcing bar 17. However, the pile head reinforcing bar 17 is not limited to the NCP anchor (registered trademark).

Next, in step S4 (first formwork installation step), the first formwork 10 is set while adjusting the installation height of the first formwork 10 using a height adjusting member such as a liner plate (not shown). , Installed on the above-mentioned leveling concrete (on the bottom surface 20a of the excavation recess 20) (see FIG. 5 (d)). At the time of this installation, the first formwork 10 is described above so as to surround the pile head of the exposed foundation pile 2 (in other words, to include the pile head of the exposed foundation pile 2 in a plan view). It is installed on the leveled concrete (on the bottom surface 20a of the excavation recess 20). After this installation, the upper surface of the pile head of the foundation pile 2 is located higher than the lower surface of the first formwork 10 and lower than the upper surface of the first formwork 10. In this way, the pile head of the foundation pile 2 is inserted into the internal space 10b of the first formwork 10.

Next, in step S5 (first backfilling step), the periphery of the first formwork 10 in the excavation recess 20 is backfilled (see FIG. 6 (e)). For this backfilling, it is preferable to use the excavated earth and sand generated when the excavation recess 20 in step S2 is formed, but other earth and sand may be used.

Next, a crushed stone layer (not shown) is installed in the portion of the bottom surface 20a'of the excavation recess 20 raised by the above-mentioned backfilling where the foundation slab 4 is constructed, and the leveled concrete (not shown) is further placed on the crushed stone layer (not shown). (Not shown) (2nd crushed stone layer installation / leveling concrete construction process). Here, in step S5 described above, the height of the upper surface of the leveling concrete constructed in this step substantially matches the height of the top edge of the first formwork 10 installed in step S4 described above. The backfill height of is adjusted accordingly. The height of the top of the first formwork 10 installed in step S4 described above may be substantially the same as the height of the lower surface of the foundation slab 4.

Next, in step S6 (reinforcing bar assembling step), the reinforcing bars 22 constituting the foundation slab 4 are assembled (see FIG. 6 (f)). In this step, the reinforcing bar 22 is assembled on the leveled concrete constructed in the second crushed stone layer installation / leveling concrete construction step described above (on the upper surface of the region backfilled in step S5 described above).

Next, in step S7 (second formwork installation step), the second formwork 25 for constructing the foundation slab 4 is installed (see FIG. 7 (g)). In this step, the second formwork 25 is placed on the leveled concrete constructed in the above-mentioned second crushed stone layer installation / leveling concrete construction step (on the upper surface of the area backfilled in the above-mentioned step S5). Will be installed. The second formwork 25 is installed so as to surround the reinforcing bar 22 assembled in step S6. Here, the second formwork 25 is a general formwork such as a metal foam. Further, the second formwork 25 has, for example, a tubular shape having an inner peripheral dimension that covers the outer peripheral dimension of the foundation slab 4, and can be formed by assembling a plurality of formwork members.

In the present embodiment, step S7 (second formwork installation step) is carried out after step S6 (reinforcing bar assembly step), but conversely, step S7 (second formwork installation step) Later, step S6 (reinforcing bar assembly step) may be carried out. Alternatively, step S6 (reinforcing bar assembly step) and step S7 (second formwork installation step) may be carried out in parallel.

Next, in step S8 (concrete placing step), the placing of the concrete 15 in the first formwork 10 and the placing of the concrete 15 in the second formwork 25 are carried out collectively (FIG. 6). 7 (K)). That is, the concrete 15 forming the pile head reinforcing structure 3 and the concrete 15 forming the foundation slab 4 are placed at the same time.

After the cast concrete 15 is hardened, the second formwork 25 is removed in step S9 (second formwork removal step) (see FIG. 8 (K)).

Next, in step S10 (second backfilling step), the excavation recess 20 is backfilled to a predetermined height (for example, the height of the ground GS) (see FIG. 8 (ko)). For this backfilling, it is preferable to use the excavated earth and sand generated when the excavation recess 20 in step S2 is formed, but other earth and sand may be used.
In this step, at least a part of the circumference of the foundation slab 4 in the excavation recess 20 can be backfilled.
As described above, the foundation 1 including the pile head reinforcing structure 3 can be constructed.

According to the present embodiment, the method of constructing the pile head reinforcing structure 3 is a foundation pile 2 placed in the ground and a foundation structure (for example, a foundation slab) constructed above the pile head of the foundation pile 2. This is a method of constructing a pile head reinforcing structure 3 that connects with 4) and reinforces the pile head of the foundation pile 2. The method of constructing the pile head reinforcing structure 3 includes an excavation recess forming step (step S2) of forming an excavation recess 20 in the ground G by excavating the ground G so as to expose the pile head of the foundation pile 2 and an exposure. The first formwork installation step (step S4) in which the tubular first formwork 10 is installed on the bottom surface 20a of the excavation recess 20 so as to surround the pile head of the foundation pile 2 and the first formwork 10 It includes a concrete placing step (step S8) in which the concrete 15 is placed therein. The first formwork 10 is made of precast concrete. The pile head reinforcing structure 3 includes a first formwork 10 and concrete 15 cast in the first formwork 10. Therefore, after the concrete 15 is placed in the first formwork 10, the first formwork 10 can be left without being removed and used as the outer shell of the pile head reinforcing structure 3. Further, since the first formwork 10 has a tubular shape, it is clearly lighter than the pile head reinforcing structure 3 made of a solid type precast member. Therefore, the labor of transportation and installation can be reduced. Therefore, it is possible to rationalize the construction of the pile head reinforcing structure 3.

Further, according to the present embodiment, the method of constructing the pile head reinforcing structure 3 is excavation after the first formwork installation step (step S4) and prior to the concrete placing step (step S8). The first backfilling step (step S5) of backfilling the periphery of the first mold 10 in the recess 20 is further included. Therefore, since the first backfilling step (step S5) can be carried out immediately after the completion of the first formwork installation step (step S4), the construction of the foundation structure such as the foundation slab 4 (steps S6 to S6) is subsequently performed. It is possible to take S10), and the entire construction period can be significantly shortened. Further, since the excavated earth and sand generated in the excavation recess forming step (step S2) can be used for the backfilling in the first backfilling step (step S5), the excavated earth and sand is immediately placed near the construction site. It can be used for the backfilling. Therefore, it is not necessary to transport and temporarily store the excavated soil in a distant place. Further, by backfilling in the first backfilling step (step S5), it is possible to suppress the occurrence of concrete leakage from the lower end of the first formwork 10 in the concrete placing step (step S8).

Further, according to the present embodiment, the method of constructing the pile head reinforcing structure 3 is the first method after the first backfilling step (step S5) and prior to the concrete placing step (step S8). A second formwork installation step (step S7) in which a second formwork 25 for constructing a foundation structure (for example, a foundation slab 4) is installed on the upper surface of the area backfilled in the backfilling step (step S5). Is further included. In the concrete placing step (step S8), the placing of the concrete 15 in the first formwork 10 and the placing of the concrete 15 in the second formwork 25 are carried out collectively. As a result, the concrete 15 forming the pile head reinforcing structure 3 and the concrete 15 forming the foundation structure (for example, the foundation slab 4) can be placed at the same time, so that the entire construction period can be further extended. It can be shortened.

Further, according to the present embodiment, the method of constructing the pile head reinforcing structure 3 is the first method after the first backfilling step (step S5) and prior to the concrete placing step (step S8). A reinforcing bar assembling step (step S6) for assembling the reinforcing bars 22 constituting the foundation structure (for example, the foundation slab 4) is further included on the upper surface of the region backfilled in the backfilling step (step S5). Therefore, since the reinforcing bar assembling step (step S6) can be carried out immediately after the completion of the first backfilling step (step S5), the entire construction period can be further shortened.

Further, according to the present embodiment, at the time of manufacturing the first formwork 10, substantially all the reinforcing bars (first reinforcing bar 11, second reinforcing bar 12, and third reinforcing bar 13) constituting the pile head reinforcing structure 3 are first. It is incorporated into the mold 10. Further, at the time of manufacturing the first formwork 10, reinforcing bars (third reinforcing bars 13) for connecting the pile head reinforcing structure 3 and the foundation structure (for example, the foundation slab 4) are installed in the first formwork 10. .. Therefore, it is possible to significantly reduce the bar arrangement work at the construction site.

Further, according to the present embodiment, the buried formwork is used at the time of manufacturing the first formwork 10. In other words, the inner surface side and / or the outer surface side of the first formwork 10 is composed of an embedded formwork. As a result, it is possible to reduce the demolding work at the time of manufacturing the first mold 10.

Further, according to the present embodiment, the method of constructing the pile head reinforcing structure 3 is after the excavation recess forming step (step S2) and prior to the concrete placing step (step S8), the foundation pile 2 The pile head reinforcing bar installation step (step S3) of installing the pile head reinforcing bar 17 on the pile head of the pile head is further included. The pile head reinforcing structure 3 is configured to further include a pile head reinforcing bar 17. As a result, the integrity of the pile head of the foundation pile 2 and the pile head reinforcing structure 3 can be improved.

Further, according to the present embodiment, the method of constructing the pile head reinforcing structure 3 includes a second formwork removing step (step S9) and a second backfilling step (step S10) after the concrete placing step (step S8). ) And more. In the second formwork removing step (step S9), the second formwork 25 is removed. In the second backfilling step (step S10), at least a part of the circumference of the foundation structure (for example, the foundation slab 4) in the excavation recess 20 is backfilled. The excavated earth and sand generated in the excavation recess forming step (step S2) can also be used for the backfilling in the second backfilling step (step S10).

Further, according to the present embodiment, the formwork (first formwork 10) used for reinforcing the pile head of the foundation pile 2 placed in the ground has a tubular shape extending in the vertical direction and is precast. A main body portion 10a made of concrete, a first reinforcing bar 11 embedded in the main body portion 10a and extending in the circumferential direction of the main body portion 10a, and a part thereof embedded in the main body portion 10a and the remaining portion in the internal space 10b of the main body portion 10a. A second reinforcing bar 12 to be exposed is provided. The pile head of the foundation pile 2 is inserted into the internal space 10b, and the concrete 15 is placed. Therefore, the formwork (first formwork 10) can be utilized as the outer shell of the pile head reinforcing structure 3.

Further, according to the present embodiment, the formwork (first formwork 10) further includes a third reinforcing bar 13 that extends upward from the upper end portion of the main body portion 10a. The third reinforcing bar 13 can be used as a connecting reinforcing bar between the pile head reinforcing structure 3 and the foundation structure (for example, the foundation slab 4).

Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 9 is a diagram showing a schematic configuration of a foundation 1'in this embodiment. Specifically, FIG. 9A is a vertical sectional view of the foundation 1', and FIG. 9B is a top view of the foundation 1'. In addition, in FIGS. 9A and 9B, for simplification of the illustration, the above-mentioned first to third reinforcing bars 11 to 13 and the pile head reinforcing bar 17 are shown, and the pedestal 31 and the underground beam 32 described later are shown. The illustration of the constituent reinforcing bars is omitted.
The points different from the above-described first embodiment will be described.

In the above-mentioned first embodiment, the basic slab 4 is adopted as an example of the "basic structure" of the present invention, but in the present embodiment, the pedestal 31 is another example of the "basic structure" of the present invention. And the underground beam 32 is adopted.

The foundation 1'is erected on a plurality of foundation piles 2, a plurality of pile head reinforcement structures 3 separately constructed on the pile heads of each foundation pile 2, and a pile head reinforcement structure 3 in the vertical direction. A pedestal 31 extending in the direction of the pedestal 31 and an underground beam 32 extending horizontally so as to connect the lower ends of adjacent pedestals 31 are included. Here, the pedestal 31 and the underground beam 32 are constructed above the pile head of the foundation pile 2.

In the present embodiment, the underground beam 32 constituting the foundation 1'is located in the ground, and at least the lower part of the pedestal 31 is located in the ground. That is, in the present embodiment, at least the lower part of the pedestal 31 and the underground beam 32 are located below the ground GS.

In the arrangement shown in FIG. 9A, nine foundation piles 2 are arranged in a matrix (3 × 3 in the figure) parallel to each other in a plan view. The number and arrangement of the foundation piles 2 constituting the foundation 1'are not limited to those shown in FIG.

In the present embodiment, the pile head reinforcing structure 3 connects the foundation pile 2 and the pedestal 31, and reinforces the pile head of the foundation pile 2. Further, the third reinforcing bar 13 of the first formwork 10 constituting the pile head reinforcing structure 3 functions as a reinforcing bar for connecting the pile head reinforcing structure 3 and the pedestal 31.

In the present embodiment, the pedestal 31 and the underground beam 32 are made of concrete (reinforced concrete (RC)) having reinforcing bars (not shown).
As shown in FIG. 9, in the present embodiment, the outer peripheral surface of the pedestal 31 and the outer peripheral surface of the pile head reinforcing structure 3 (the outer peripheral surface of the first formwork 10) are substantially flush with each other.

In the present embodiment, the underground beam 32 is connected to the pile head reinforcing structure 3 via the pedestal 31 (that is, indirectly), but in addition to this, the underground beam 32 is connected to the pile head reinforcing structure 3. May be directly linked to.

Therefore, according to the present embodiment and the first embodiment described above, it is easy that the "foundation structure" of the present invention may include at least one of the foundation slab 4, the pedestal 31, and the underground beam 32. Will be understood by.

The illustrated embodiments merely illustrate the present invention, and the present invention makes various improvements and modifications made by those skilled in the art within the scope of the claims, in addition to those directly shown by the described embodiments. It goes without saying that it is an inclusion.

1,1'... foundation, 2 ... foundation pile, 3 ... pile head reinforcement structure, 4 ... foundation slab, 6 ... yatko, 10 ... first formwork, 10a ... main body, 10b ... internal space, 11 ... first Reinforcing bar, 12 ... 2nd reinforcing bar, 13 ... 3rd reinforcing bar, 15 ... Concrete, 17 ... Pile head reinforcement, 20 ... Excavation recess, 20a, 20a'... Bottom surface, 22 ... Reinforcing bar, 25 ... 2nd formwork, 31 ... Pedestal, 32 ... Underground beam, G ... Ground, GS ... Ground

Claims (10)

A method of connecting a foundation pile placed in the ground and a foundation structure constructed above the pile head of the foundation pile and constructing a pile head reinforcement structure for reinforcing the pile head. And
An excavation recess forming step of forming an excavation recess in the ground by excavating the ground so as to expose the pile head,
A first formwork installation step of installing a tubular first formwork on the bottom surface of the excavation recess so as to surround the exposed pile head.
The concrete placing process of placing concrete in the first formwork and
Including
The first formwork is made of precast concrete and
The pile head reinforcing structure includes the first formwork and concrete cast in the first formwork.
How to build a pile head reinforcement structure. The claim further includes a first backfilling step of backfilling the periphery of the first formwork in the excavation recess after the first formwork installation step and prior to the concrete placing step. The method for constructing a pile head reinforcing structure according to 1. After the first backfilling step and prior to the concrete placing step, a second formwork for constructing the foundation structure is installed on the upper surface of the backfilled area. Including the second formwork installation process
The pile head reinforcing structure according to claim 2, wherein in the concrete placing step, the concrete placing in the first formwork and the concrete placing in the second formwork are carried out collectively. How to build. After the first backfilling step and prior to the concrete placing step, the reinforcing bar assembling step of assembling the reinforcing bars constituting the foundation structure is further included on the upper surface of the backfilled area. , The method for constructing the pile head reinforcing structure according to claim 2 or 3. The pile head according to any one of claims 1 to 4, wherein substantially all of the reinforcing bars constituting the pile head reinforcing structure are incorporated into the first form at the time of manufacturing the first form. How to build a reinforced structure. Any one of claims 1 to 5, wherein a reinforcing bar for connecting the pile head reinforcing structure and the foundation structure is installed in the first formwork at the time of manufacturing the first formwork. How to construct the pile head reinforcement structure described in. The method for constructing a pile head reinforcing structure according to any one of claims 1 to 6, wherein an embedded form is used at the time of manufacturing the first form. A pile head reinforcing bar installation step of installing a pile head reinforcing bar on the pile head is further included after the excavation recess forming step and prior to the concrete placing step.
The method for constructing a pile head reinforcing structure according to any one of claims 1 to 7, wherein the pile head reinforcing structure further includes the pile head reinforcing bar. A formwork used to reinforce the pile head of a foundation pile placed underground.
The main body, which has a tubular shape extending in the vertical direction and is made of precast concrete,
A first reinforcing bar embedded in the main body and extending in the circumferential direction of the main body,
A second reinforcing bar that is partially embedded in the main body and the rest is exposed in the internal space of the main body.
With
A formwork in which the pile head is inserted into the internal space and concrete is cast. The mold according to claim 9, further comprising a third reinforcing bar that is exposed and extends upward from the upper end portion of the main body portion.

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