WO2016181669A1

WO2016181669A1 - Rigid connection structure for bottom end of pillar and concrete pile

Info

Publication number: WO2016181669A1
Application number: PCT/JP2016/052411
Authority: WO
Inventors: 雄士美島; 晋作清水; 拓也大庭; 森田　寛之
Original assignee: 日立造船株式会社
Priority date: 2015-05-08
Filing date: 2016-01-28
Publication date: 2016-11-17
Also published as: JP2016211215A; CN107532398A; JP6021993B1; PH12017501821B1; KR20170131604A; PH12017501821A1; CN107532398B; KR102079692B1

Abstract

A rigid connection structure (10) for a bridge-pier bottom end (4) and an RC pile (6) is provided with the following: an extension portion (12) that extends downward from the bridge-pier bottom end (4) and is mounted on the RC pile (6); an outer vertical rib group (40) that is provided on an outer surface of a lower extension portion (23), which is the lower portion of the extension portion (12), the outer vertical rib group having formed therein a plurality of displacement prevention holes (8); and outer concrete (16) that is cast onto the outer peripheral portion of the lower extension portion (23). The outer concrete (16) has embedded therein the outer vertical rib group (40) and a main rebar (60) that extends upward from the inside of the RC pile (6).

Description

Rigid connection structure of lower end of support and concrete pile

The present invention mainly relates to a rigidly connected structure of a pillar lower end and a concrete pile such as a three-dimensional crossing bridge, a viaduct, an elevated structure, a general bridge, or a railway bridge.

As shown in FIG. 1, a heavy building such as a road bridge 1 has a configuration in which the load is transmitted to the ground 5 by a bridge pier 3 as a support. In this ground 5, the pier lower end 4, which is the lower end of the pier 3, and the RC pile 6 (concrete reinforced with reinforcing bars) arranged vertically are rigidly connected by the

rigid structures

10, 100. Yes.

The load acting on the building is mainly in the vertical direction due to its own weight and in the horizontal direction due to earthquakes. In particular, in countries where earthquakes occur frequently, such as Japan, horizontal loads frequently act on buildings, so the importance of rigid structures that generate large bending moments due to these loads increases.

As a conventional rigid structure, there has been proposed a structure in which a large number of displacement preventing holes (perforated steel plate gibber: PBL) are formed in an extended portion extending downward from a lower end portion of a pier (see, for example, Patent Document 1). ). The rigid structure described in Patent Document 1 has a configuration in which the extension portion itself transmits the load in the horizontal direction from the lower end portion of the pier to the RC pile as a strength member.

Japanese Patent No. 4691690

By the way, in the rigid structure described in the above-mentioned patent document 1, what is formed with a perforated steel plate gibber is an extended portion, that is, a large steel structure extended downward from the lower end of the pier. For this reason, it is not easy to form a perforated steel plate gibel in the extension, resulting in increased manufacturing time and cost. On the other hand, when the cross section at the lower end of the pier is small, the distance between the main reinforcing bar from the concrete pile and the extension as the strength member (part made of concrete) becomes large. If the interval is large, the tensile force may not be smoothly transmitted to the main reinforcing bar, and cone breakage may occur. Therefore, some reinforcement is necessary to improve reliability.

Therefore, an object of the present invention is to provide a rigid structure of a column lower end portion and a concrete pile that can reduce manufacturing time and cost and can improve reliability.

In order to solve the above-mentioned problem, a rigid structure according to the first invention is a rigid structure of a lower end portion of a support and a concrete pile,
An extension that extends downward from the lower end of the column and is placed on the concrete pile,
An outer vertical rib group provided on the outer surface of the extension part and formed with a number of anti-slip holes;
With external concrete cast on the outer periphery of the extension,
The external concrete embeds a reinforcing bar group extending upward from the inside of the concrete pile and the outer vertical rib group.

Further, the rigid structure according to the second invention is the rigid structure according to the first invention, the inner vertical rib group provided on the inner surface of the extension portion and formed with a number of detent holes,
An internal concrete placed inside the extension,
The internal concrete embeds the inner vertical rib group.

Furthermore, the rigid structure according to the third aspect of the invention is the rigid structure according to the first or second aspect of the invention, comprising a vertical cylindrical portion connected to the outer vertical rib group and surrounding the outside of the extension portion,
The said vertical cylinder part becomes a formwork at the time of placing external concrete.

In addition, in the rigid structure according to the fourth invention, the extension in the rigid structure according to the first or second invention has a cylindrical shape,
An outer vertical rib group consists of many outer vertical ribs arrange | positioned radially from the outer surface of the said extension part.

Further, the rigid structure according to the fifth aspect of the invention is the outer peripheral reinforcement group in which the reinforcing bars embedded in the external concrete in the rigid structure according to the first or second aspect of the invention are main reinforcing bars that reinforce the concrete pile. And an inner periphery reinforcing bar group which is a reinforcing bar fixed to the outer peripheral reinforcing bar group inside the concrete pile.

According to the rigid structure of the lower end of the support column and the concrete pile, the outer vertical rib group embedded in the external concrete sufficiently reduces the stress generated when transmitting the load from the lower end of the support column. Therefore, it is not necessary to form an anti-displacement hole, and as a result, manufacturing time and cost can be reduced. Moreover, since the space | interval between the reinforcing bar group from a concrete pile and an outer vertical rib group becomes small, tensile force is smoothly transmitted to the main reinforcing bar from an outer vertical rib group. Thereby, cone destruction caused by tensile force is suppressed, and as a result, reliability can be improved.

1 is a general side view of a road bridge using a rigid structure according to an embodiment of the present invention. It is a longitudinal cross-sectional view of the rigid structure which concerns on Example 1 of this invention. It is the perspective view which abbreviate | omitted the external concrete of the rigid connection structure. FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is a cross-sectional view for demonstrating the cross-sectional secondary moment of an outer vertical rib group. It is a figure and graph for demonstrating the stress which generate | occur | produces when there is no inner vertical rib group. It is a figure and graph for demonstrating the stress which generate | occur | produces when there exists an inner vertical rib group. It is a longitudinal cross-sectional view of the state which arrange | positions the reinforcing bar of RC pile in the construction procedure of the rigid structure. It is a longitudinal cross-sectional view of the state which lays concrete of RC pile in the construction procedure of the rigid structure. It is a longitudinal cross-sectional view of the state which completes RC pile in the construction procedure of the rigid structure. It is a longitudinal cross-sectional view of the state which mounts the steel part in a rigid structure on RC pile in the construction procedure of the rigid structure. It is a longitudinal cross-sectional view of the state which casts concrete in the part made from the steel in the construction procedure of the rigid structure. It is a longitudinal cross-sectional view of the state which joins a pier lower end part in the construction procedure of the rigid structure. It is a cross-sectional view of the rigid structure according to the second embodiment of the present invention, and corresponds to FIG. It is a cross-sectional view of the rigid structure, and corresponds to FIG.

Hereinafter, a rigid structure of a lower end portion of a support and a concrete pile according to an embodiment of the present invention will be described with reference to the drawings.

First, a road bridge, which is an example of a building using the rigid structure, will be briefly described.

As shown in FIG. 1, the road bridge 1 includes a bridge girder 2 through which people or vehicles pass, and a plurality of bridge piers 3 (an example of support columns) that support the bridge girder 2. The lower ends of these piers 3, that is, the lower ends of the piers 4 (which are an example of the lower ends of the columns) are rigidly attached to columnar RC piles 6 (concrete reinforced with reinforcing bars) arranged vertically on the ground 5. It is tied. Rigidly connecting the pier lower end 4 and the RC pile 6 is the

rigid structure

10, 100.

Hereinafter, the rigid structure 10 according to the first embodiment of the present invention will be described with reference to FIGS.

As shown in FIGS. 2 and 3, the rigid structure 10 includes, as steel portions 12 to 15, an extension portion 12 extending downward from the pier lower end portion 4 and a lower portion of the extension portion 12. A vertical cylindrical portion 13 that surrounds the outside of a lower extension 23 (described later in detail), and an outer vertical rib group 14 and an inner vertical rib group 15 (strength members provided on the outer surface and the inner surface of the lower extension 23, respectively) 2). Further, as shown in FIG. 2 (omitted in FIG. 3), the rigid structure 10 is formed as a concrete portion 16-18 between the lower extension 23 and the vertical cylinder 13 (that is, the lower extension). Between the outer concrete 16 placed on the outer periphery of the portion 23), the inner concrete 17 placed inside the lower extension 23, the lower extension 23, the vertical tube portion 13, and the RC pile 6. And a lower concrete 18 which is a cross-sectional transition portion placed on the surface.

The extension portion 12 is placed on the pile head 7 of the RC pile 6 via an installation stand 68 (H-shaped steel or the like) as shown in FIG. 2 and 3, the extension portion 12 includes a diaphragm 20 disposed horizontally at the upper end height of the outer longitudinal rib group 14 and the inner longitudinal rib group 15, and an upper upper portion by the diaphragm 20. The extension portion 22 includes a lower extension portion 23 below the diaphragm 20. The diaphragm 20 has an opening 21 into which ready-mixed concrete for the internal concrete 17 is poured from above. As shown in FIG. 3, the upper extension portion 22 and the lower extension portion 23 have a cylindrical shape concentric with the RC pile 6 and have a smaller diameter than the RC pile 6. As shown in FIG. 2, the lower extension 23 does not have anything other than the inner concrete 17 and the inner vertical rib group 15 in the interior thereof for the workability when placing the inner concrete 17. In addition, since it is mainly the outer longitudinal rib group 14 and not the extension part 12 itself that transmits the load from the pier lower end part 4 to the external concrete 16, the extension part 12 is provided with a stopper hole (perforated steel plate gibber: PBL) need not be formed.

As shown in FIG. 3, the vertical cylinder portion 13 has a cylindrical shape concentric with the RC pile 6 and the extension portion 12, and has a slightly larger diameter than the RC pile 6. The lower end of the vertical cylinder part 13 is slightly lower than the pile head 7 of the RC pile 6, and the upper end of the vertical cylinder part 13 is the same height (or higher) as the outer vertical rib group 14. Moreover, the said vertical cylinder part 13 is in contact with the soil of the ground 5 in the outer surface, as shown in FIG. In addition, the said vertical cylinder part 13 is the secondary member (including corrosion margin) which functions as a formwork for placing the external concrete 16, and a band reinforcement after the placement.

The outer vertical rib group 14 is composed of a plurality of outer vertical ribs 40 arranged radially at equal pitches from the outer peripheral surface of the lower extension 23, as shown in FIGS. As shown in FIGS. 3 and 5, each outer vertical rib 40 has a large number of anti-slip holes 8 (perforated holes) penetrating in the horizontal direction in order to transmit the load from the pier lower end 4 to the external concrete 16. Steel plate gibber (PBL) is regularly formed. The large number of outer vertical ribs 40 constituting the outer vertical rib group 14 reach the vertical cylinder part 13 and do not reach the wide outer vertical ribs 40 connected to the vertical cylinder part 13 and the vertical cylinder part 13. There is a narrow outer longitudinal rib 40. The wide outer vertical ribs 40 are arranged at an equal pitch (for example, 90 ° pitch) in order to appropriately hold the vertical cylinder portion 13.

The upper end of the inner vertical rib group 15 is connected to the outer edge portion of the lower surface of the diaphragm 20 as shown in FIG. Further, the inner vertical rib group 15 includes a plurality of inner vertical ribs 50 arranged at an equal pitch from the inner peripheral surface of the lower extension 23 toward the axis as shown in FIGS. 4 and 5. Each of the inner vertical ribs 50 has a large number of slip stoppers penetrating in the same horizontal direction as the outer vertical ribs 40 in order to transmit the load from the pier lower end 4 to the inner concrete 17 as shown in FIG. Holes 8 (perforated steel plate gibber: PBL) are regularly formed.

As will be described in detail later, the outer vertical rib 40 contributes to an increase in the sectional moment than the inner vertical rib 50. Therefore, as shown in FIGS. 4 and 5, the outer vertical rib 40 is larger than the inner vertical rib 50. Designed to be Further, since the outer vertical ribs 40 and the inner vertical ribs 50 cooperate as strength members, all the inner vertical ribs 50 are arranged to face the outer vertical ribs 40 via the lower extension 23.

The outer concrete 16 embeds the outer longitudinal rib group 14 and the main reinforcing bar 60 from the RC pile 6 as shown in FIGS. 4 and 5. The main reinforcing bars 60 are a number of reinforcing bars arranged at equal pitches on the outer edge of the RC pile 6 in order to increase the tensile strength of the RC pile 6. Further, as shown in FIG. 2, the main reinforcing bar 60 is not only disposed inside the RC pile 6 but also protrudes from the pile head 7 of the RC pile 6 to near the upper end of the outer vertical rib group 14. That is, the external concrete 16 receives a tensile load from the outer vertical rib group 14 and transmits this load from the main reinforcing bar 60 to the RC pile 6. In addition to the main reinforcing bar 60, a band reinforcing bar 61 bound to the main reinforcing bar 60 is also arranged inside the RC pile 6.

The inner concrete 17 embeds the inner longitudinal rib group 15 as shown in FIG. That is, the internal concrete 17 is a load to which the internal vertical rib group 15 is transmitted. On the other hand, as shown in FIG. 2, the lower concrete 18 embeds the main rebar 60 and the installation stand 68. Moreover, the said lower concrete 18 is designed so that it may damage before the other part of the said rigid structure 10 as a reliability design.

Next, the function of the outer vertical rib group 14 will be described with reference to FIG.

When a horizontal load F acts on the bridge girder 2 due to an earthquake or the like, a large bending moment is exerted on the bridge pier 3 and the rigid structure 10 serving as a cantilever by the rigid structure 10 serving as a support portion of the cantilever. M is generated. As shown in FIG. 6, due to this large bending moment M, tensile stress and compressive stress with the neutral axis A as a boundary are generated in the outer longitudinal rib group 14 which is a strength member of the rigid structure 10. It is known from the formula of material mechanics that the tensile stress and the compressive stress are proportional to the value obtained by dividing the bending moment M by the sectional secondary moment of the outer longitudinal rib group 14. That is, when the bending moment M is constant, the tensile stress and the compressive stress that are generated become smaller as the secondary moment of the section is larger. In general, it is known that the moment of inertia of the cross section increases as the cross section is located at a position away from the neutral axis A. Here, the outer vertical rib 40 is provided at the outer surface of the lower extension 23, that is, at a position away from the neutral axis A. For this reason, the rigid structure 10 according to the first embodiment has a larger cross section than the conventional structure having the lower extension portion as a strength member as described in Patent Document 1 as a prior art document. Since it has the next moment, the stress generated when transmitting the load from the pier lower end 4 is reduced. In addition, the rigid structure 10 includes the outer vertical rib group 14, and as shown in FIGS. 4 and 5, the main reinforcing bar 60 and the strength member (outer vertical rib group 14) from the RC pile 6 are used. Therefore, the tensile force is smoothly transmitted from the outer longitudinal rib group 14 to the main reinforcing bar 60. This suppresses cone breakage caused by tensile force.

Next, the function of the inner vertical rib group 15 will be described with reference to FIGS.

Here, in the case of the above-mentioned Patent Document 1, since a slip-preventing hole (perforated steel plate gibber: PBL) is formed in the extension portion, the pier and the concrete in the inside cooperate together. However, according to the present invention, since the anti-displacement hole is not formed in the extension portion 12, the pier 3 and the internal concrete 17 are separated from each other as in the case of Patent Document 1 without cooperation as a unit. Therefore, in order to suppress the peeling / stress concentration (support pressure) between the steel plate and the concrete caused by the integration of the cross section and the sudden change in the cross section between the lower extension 23 and the vertical cylinder 13, the inner peripheral portion of the lower extension 23 The inner vertical rib group 15 is installed in Experimental results on the function of the inner vertical rib group 15 are shown in FIGS. FIG. 7 shows a case where the inner vertical rib group 15 is not present on the inner peripheral portion of the lower extension 23, and FIG. 8 shows a case where the inner vertical rib group 15 is present on the inner peripheral portion of the lower extension 23. FIGS. 7 and 8 show calculated values and simulations of the stress generated in the rigid structure 10 when a horizontal load F and a vertical load (axial force) are applied to the pier 3. Finite element method: FEM) value. In FIG. 8, since the calculated value and the simulation value match, the calculation value is hidden behind the simulation value. In the graphs shown on the right side of FIG. 7 and FIG. 8, the horizontal axis is the axis of stress σ with positive tensile stress (compressive stress is negative), and the vertical axis corresponds to the position of the cross section of the rigid structure 10. Is the axis. Further, in the cross section (left half) of the rigid structure 10 shown on the left side of FIGS. 7 and 8, the position in the vertical direction corresponds to the vertical axis of the graph. As shown in FIG. 7 and FIG. 8, the calculated value, that is, the theoretical value in the case where the steel portion of the rigid structure 10 and the internal concrete 17 cooperate as a unit, Become. On the other hand, in the simulation (finite element method: FEM) value, as shown in FIG. 7, when there is no inner longitudinal rib group 15, the boundary between the lower extension 23 and the inner concrete 17 becomes discontinuous. When the inner longitudinal rib group 15 is present as shown in FIG. For this reason, from FIG. 7 and FIG. 8, the steel portion and the internal concrete 17 in the rigid structure 10 do not cooperate as a unit when the inner vertical rib group 15 is not provided. It can be seen that if there is, it will cooperate as one. For this reason, the rigid structure 10 includes the inner vertical rib group 15 embedded in the internal concrete 17, thereby reducing the stress generated when the load from the pier lower end 4 is transmitted.

Hereinafter, a method for manufacturing the rigid structure 10 according to the first embodiment, that is, a procedure for on-site construction will be described.

First, as shown in FIG. 9, a stand pipe 91 is built in the ground 5, and the reinforcing

bars

60 and 61 of the RC pile 6 are arranged in a hole 92 formed by excavating the stand pipe 91 to a predetermined depth. Then, as shown in FIG. 10, after the concrete of the RC pile 6 is placed in the drilling hole 92, the concrete in the stand pipe 91 is formed with a chisel to complete the RC pile 6 as shown in FIG. 11. . Thereafter, an installation stand 68 is arranged on the pile head 7 of the RC pile 6, and as shown in FIG. 12, the steel portion (extension portion 12, vertical cylinder portion 13, outer vertical rib group 14 and The portion comprising the inner vertical rib group 15) is placed on the installation stand 68. Next, as shown in FIG. 13, after placing the lower concrete 18, the outer concrete 16, and the inner concrete 17, the stand pipe 91 is removed and backfilled as shown in FIG. By joining the lower end of the pier lower end portion 4 to the upper end of the portion 22, the rigid structure 10 of the pier lower end portion 4 and the RC pile 6 is manufactured.

As described above, according to the rigid structure 10 according to the first embodiment, the stress generated when the load from the pier lower end portion 4 is transmitted by the outer vertical rib group 14 embedded in the external concrete 16 is sufficiently small. As a result, it is not necessary to form the anti-displacement hole 8 in the extension portion 12, and as a result, manufacturing time and cost can be reduced. Further, since the distance between the main reinforcing bar 60 from the RC pile 6 and the strength member (outer vertical rib group 14) is small and substantially constant, the tensile force is smoothly transmitted from the outer vertical rib group 14 to the main reinforcing bar 60. . Thereby, cone destruction caused by tensile force is suppressed, and as a result, reliability can be improved.

Furthermore, since the steel part in the rigid structure 10 and the internal concrete 17 cooperate together by the internal vertical rib group 15 embedded in the internal concrete 17, when transmitting the load from the pier lower end 4. The generated stress is further reduced, and as a result, reliability can be improved. Further, it is possible to suppress the peeling and stress concentration (support pressure) between the steel plate and the concrete caused by the integration of the cross section and the sudden change in cross section between the lower extension portion 23 and the vertical cylinder portion 13.

In addition, the installation and removal of a separate formwork is omitted because the vertical cylinder portion 13 that becomes a formwork when placing the external concrete 16 is buried in the field construction, so that the manufacturing time and Cost can be reduced.

Further, since the lower extension 23 is cylindrical and the outer vertical rib group 14 is composed of a large number of outer vertical ribs 40 arranged radially from the outer surface of the lower extension 23, stress concentration does not occur. It is not necessary to arrange a buffer member for stress distribution between the longitudinal ribs 40, and as a result, manufacturing time and cost can be reduced.

Furthermore, since it is not necessary to form the slip prevention hole 8 in the extension portion 12, the outer longitudinal ribs 40 arranged radially at an equal pitch from the outer peripheral surface of the lower extension portion 23 can be further increased (densely). Is possible. Thereby, it is possible to suppress the peeling and stress concentration (support pressure) between the steel plate and the concrete caused by the sudden change in the cross section between the lower extension portion 23 and the vertical cylinder portion 13.

The rigid structure 100 according to the second embodiment of the present invention is obtained by increasing the number of reinforcing bars embedded in the external concrete 16 of the rigid structure 10 according to the first embodiment.

Hereinafter, the description will be made by paying attention to the reinforcing bars which are different from the first embodiment, and the same components as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

In the rigid structure 10 according to the first embodiment, as shown in FIG. 5, the distance between the main reinforcing bar 60 and the outer vertical rib group 14 from the RC pile 6 is small. Cone destruction that tends to occur is suppressed. In order to further suppress the cone breakage, as shown in FIG. 15 of the second embodiment corresponding to FIG. 5 of the first embodiment, a reinforcing reinforcing bar 62 is provided on the inner peripheral side of the main reinforcing bar 60. 10 shows a rigid structure 100 according to a second embodiment. That is, the external concrete 16 of the rigid structure 100 according to the second embodiment includes the reinforcing bars 62 (inner reinforcing bars) in addition to the outer longitudinal ribs 40 and the main reinforcing bars 60 (a group of outer peripheral reinforcing bars) from the RC pile 6. It is also a buried peri-bar rebar group.

As shown in FIG. 15, the reinforcing reinforcing bars 62 are composed of the same number of reinforcing bars as the main reinforcing bars 60, and are disposed closer to the axis than the main reinforcing bars 60. Further, as shown in FIG. 16 of the second embodiment corresponding to FIG. 2 of the first embodiment, the lower part of the reinforcing reinforcing bar 62 is fixed to the main reinforcing bar 60 inside the RC pile 6, and the middle part of the reinforcing reinforcing bar 62 Is inclined from the main reinforcing bar 60 in the direction of the axial center, and the upper part of the reinforcing reinforcing bar 62 protrudes vertically from the pile head 7 of the RC pile 6. The lower part of the reinforcing reinforcing bar 62, that is, the part fixed to the main reinforcing bar 60, has a length necessary for transmitting the load from the external concrete 16 to the RC pile 6. The middle part of the reinforcing reinforcing bar 62 is inclined so as not to hinder the transmission of the load. The upper end of the reinforcing reinforcing bar 62 has the same upper end as the upper end of the main reinforcing bar 60.

Hereinafter, the manufacturing method of the rigid structure 100 according to the second embodiment, that is, the procedure for on-site construction will be described.

In the manufacturing method of the rigid structure 100 according to the second embodiment, in the manufacturing method of the rigid structure 10 according to the first embodiment, the reinforcing bars of the RC pile 6 arranged in the drilling hole 92 shown in FIG. It is not the thing of the said Example 1 (the main reinforcement 60 and the strip reinforcement 61) but the reinforcement (the main reinforcement 60, the reinforcement reinforcement 62, and the belt reinforcement 61) of the present Example 2. The other construction procedure of the second embodiment is the same as the construction procedure of the first embodiment.

As described above, according to the rigid structure 100 according to the second embodiment, the same effect as that of the rigid structure 10 according to the first embodiment can be obtained. As a result, reliability can be improved.

By the way, in the said embodiment and Example 1 and 2, although the bridge pier 3 (bridge pier lower end part 4) was demonstrated as an example of a support | pillar (support lower end part), it is not limited to this, A building is supported. Anything is acceptable.

Further, in the above-described embodiment and Examples 1 and 2, the displacement preventing hole 8 (perforated steel plate gibber: PBL) of the outer longitudinal rib 40 and the inner longitudinal rib 50 has not been described in detail. You may provide a penetration reinforcing bar as a slip prevention member made to do.

Furthermore, in the said Example 1 and 2, although demonstrated that the extension part 12 was mounted in the pile head 7 of RC pile 6 via the installation mount 68 (H-shaped steel etc.), you may mount directly. .

In addition, in

Embodiments

1 and 2 described above, the extension portion 12 has been described as having a cylindrical shape, but may have a rectangular tube shape. In addition, since stress concentration is likely to occur if the rectangular tube shape is used, a buffer member for stress distribution is required, but the manufacturing time and cost are reduced when the pier lower end portion 4 is a rectangular tube shape. Can do.

Further, in the second embodiment, as shown in FIG. 15, it is described that the reinforcing reinforcing bars 62 are composed of the same number of reinforcing bars as the main reinforcing bars 60, but it is not always necessary to have the same number. The number of reinforcing bars 62 and the diameter of the reinforcing bars are set so as to satisfy the amount of reinforcing bars necessary for suppressing cone fracture.

Claims

A rigid structure of the lower end of the column and the concrete pile,
An extension that extends downward from the lower end of the column and is placed on the concrete pile,
An outer vertical rib group provided on the outer surface of the extension part and formed with a number of anti-slip holes;
With external concrete cast on the outer periphery of the extension,
The rigid structure of a pillar lower end and a concrete pile, wherein the external concrete embeds a reinforcing bar group extending upward from the inside of the concrete pile and the outer longitudinal rib group.
An inner longitudinal rib group provided on the inner surface of the extension portion and formed with a number of anti-slip holes;
An internal concrete placed inside the extension,
2. The rigid structure of a column lower end and a concrete pile according to claim 1, wherein the inner concrete embeds the inner vertical rib group.
A vertical cylinder connected to the outer vertical rib group and surrounding the outside of the extension;
The rigid structure of the lower end part of a support | pillar and a concrete pile of Claim 1 or 2 whose said vertical cylinder part becomes a formwork at the time of placing external concrete.
The extension is cylindrical,
The rigidly connected structure of the lower end portion of the column and the concrete pile according to claim 1 or 2, wherein the outer vertical rib group includes a plurality of outer vertical ribs arranged radially from the outer surface of the extension portion.
Reinforcing steel bars embedded in external concrete are composed of outer reinforcing steel bars, which are main reinforcing bars for reinforcing concrete piles, and inner reinforcing steel bars, which are reinforcing steel bars fixed to the outer reinforcing steel bars inside the concrete pile. The rigid structure of the support | pillar lower end part and concrete pile of Claim 1 or 2.