JP2006104747A - Pier stud connection structure and pier stud connecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pier stud connection structure which occupies a small construction area, contributes to a shortened construction period and reduced construction costs, and exerts sufficient durability at a connection, and to provide a pier stud connecting method. <P>SOLUTION: The pier stud connection structure for connecting between a pile head 3a of an RC pile 3 and a base structure 4b of a steel square cylindrical pier 4, is implemented by a connection unit 5 which is formed of the base structure 4b; an extended plate 15 extended from each flange 12 of the base structure 4b; connecting reinforcements 8 protruded upward form the pile head 4b; and a cylindrical steel shell 21 externally fitted onto the base structure 4b and the connecting reinforcements 8, and rigidly connected to the base structure 4b via the extended portions 15, to thereby restrain poured joining concrete 31 from the periphery. According to the pier stud connection structure, a number of deviation preventive holes 16 are formed in webs 11, the flanges 12, ribs 13, 14, and the extended portions 15 of the base structure 4b, for transmitting shearing force from the base structure 4b via the joining concrete 31 to the pile head 3a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a junction structure and a joining method for a pedestal that joins a steel pile and a concrete pile such as a three-dimensional intersection bridge, a viaduct, an elevated structure, a general bridge, and a railway bridge.

Conventionally, the joint of a bridge pier that joins a concrete pile driven into the ground (hereinafter referred to as RC pile) and a steel pedestal is provided with a footing on the top of one or more RC piles. Patent Documents 1 and 2 disclose joining of base ends of pedestals. Moreover, what joins a pile and a pedestal with an anchor bolt is disclosed by patent document 3, and also what embeds a leg column in a pile and joins is disclosed by patent document 4. FIG.
JP-A-9-71949 JP 2004-68338 A JP 2000-291146 A JP 2001-348887 A

  However, in the case of the joint structure by footing in Patent Documents 1 and 2, complicated construction work such as formwork is accompanied and the construction period tends to be long. In addition, the area required for construction on site increases, and if the concrete placement area is large when footing is formed, it is easily affected by the weather. For this reason, it is difficult to secure a construction site, and it is not suitable for construction such as a multilevel crossing bridge with a short construction period. Moreover, in the case of the joint structure by the anchor bolt of patent document 3, there existed a problem that complicated construction work was accompanied and the construction work period was long. Further, in Patent Documents 1 to 3, it is difficult to ensure dimensional accuracy. In addition, in the case of the joint structure in which the pedestal is embedded in the pile of Patent Document 4, it is necessary to construct the reinforcing bar rod and socket steel pipe in the embedding part after constructing the foundation pile before installing the pedestal, so the construction procedure is complicated As a result, the construction period could be long.

  The present invention solves the above-mentioned problems, reduces the construction area occupied by the site construction, shortens the construction period, reduces the construction cost, and ensures the joint structure and joining method of the pedestal that can ensure sufficient joint strength The purpose is to provide.

  The invention according to claim 1 is a joint structure of a pedestal that connects a pile head of a concrete pile and a base of a steel cylindrical leg, the base structure of the cylindrical leg, and the base An extension projecting from the outer plate of the structure, a joint reinforcing bar protruding upward from the pile head, and a base structure externally fitted to the base structure and the joint reinforcing bar via the extension A joining unit comprising a cylindrical steel shell constrained to the outer periphery of the joining concrete that is connected and fixed to the inside, and at least the outer plate of the base structure is provided with the joining concrete from the base structure. A number of slip holes are formed to transmit shearing force to the pile head via

According to a second aspect of the present invention, the cylindrical leg is a rectangular tube leg having a rectangular cross section, and the extension portion is formed by extending from the outer plate of the base structure.
According to a third aspect of the present invention, the cylindrical leg is a cylindrical leg having a circular cross section, and the extension portion is projected in the radial direction from the outer plate of the base structure.

The invention described in claim 4 is provided with an extra insertion portion in which a cylindrical steel shell is externally fitted downward from the top of the pile head, and a slip prevention hole is formed in each of the reinforcing rib and the extension portion of the base structure. .
According to the fifth aspect of the present invention, an anti-slip member is disposed in the anti-slip hole in a portion where the shearing force applied to the base structure is large.

  In the invention according to claim 6, when the base of the steel cylindrical leg is connected to the pile head of the concrete pile, the base structure of the cylindrical leg in which a large number of slip holes are formed on the outer plate. A joining unit that connects and fixes a cylindrical steel shell that is externally fitted to the base structure via an extension protruding from the outer plate of the base structure, and a cylindrical leg that is attached to the pile head via the joining unit. The connecting rebar protruding from the pile head is placed in the cylindrical steel shell, the concrete for bonding is placed in the cylindrical steel shell, the pile head and the cylindrical leg are joined, and the cylindrical steel shell Thus, the concrete for bonding is evenly restrained, and shear force is transmitted from the base structure to the pile head through the detent hole.

  According to the seventh aspect of the present invention, when the joining unit is mounted, an extra insertion portion is formed to externally fit the cylindrical steel shell downward from the top of the pile head, and is prevented from slipping in a retaining hole at a portion where a large shear force is applied. The members are arranged.

  In the invention according to claim 8, when the joining unit is fitted to the pile head, the outer peripheral portion of the pile head at least the height of the extra portion is cut to make the pile head smaller than the inner diameter of the cylindrical steel shell. Is.

  According to the first or sixth aspect of the present invention, the cylindrical steel shell is displaced substantially in accordance with the behavior of the base structure by integrally connecting and fixing the base structure and the cylindrical steel shell via the extension. The bearing pressure and peeling force can be greatly reduced compared to socket bases. In addition, by constraining the joining concrete uniformly with the circular steel shell, it is possible to prevent the splitting fracture of the joining concrete, restrain the strain of the joining concrete, and sufficiently exert the shear strength due to the anti-displacement hole. As a result, the shearing force can be satisfactorily transmitted from the base structure to the concrete pile through the bonding concrete, and crushing can be prevented. Therefore, the occupation area of the construction can be reduced by the joining unit, the construction period can be shortened, the construction cost can be reduced, and sufficient joint strength can be ensured.

  According to invention of Claim 4, since the extra part which makes the lower part of a cylindrical steel shell externally fit to a pile head was provided in the boundary part of a joining unit and a concrete pile, this connection part protrudes from a concrete pile. Therefore, it is possible to improve the horizontal shear strength by reducing the stress concentration due to the sudden change of the cross section.

  According to the fifth aspect of the present invention, when the anti-slip holes formed on the outer plate of the base structure are formed, the anti-slip holes are shared by the displacement of the individual anti-slip holes depending on the rigidity of the steel plate. Shear force is also different. For this reason, the shear force can be improved by arranging the anti-slip member in the stop hole having a large shearing force, and the shearing force can be satisfactorily transmitted from the base structure to the joining concrete.

  According to the seventh aspect of the present invention, at the boundary between the joining unit and the concrete pile, the stress concentration due to the sudden change in the cross section is alleviated by the extra portion where the lower part of the cylindrical steel shell is externally fitted to the pile head. Yield can be improved. In addition, the shear force is increased and the slip prevention member is arranged in the stop hole, so that the shear strength can be further improved, and the shear force is transmitted well from the base structure to the concrete pile through the joining concrete. be able to.

  According to the eighth aspect of the present invention, by reducing the diameter of the pile head corresponding to the extra portion smaller than the inner diameter of the cylindrical steel shell without making the cylindrical steel shell larger than necessary, the corners of the concrete pile and corner The displacement of the tube leg can be absorbed to reduce the dimensional accuracy during construction, and the construction can be facilitated and the construction period can be shortened.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
As shown in FIG. 8, for example, it relates to the joint structure of the pier (leg column) 2 of the three-dimensional crossing bridge 1 having a span girder length L of about 200 m, for example, as shown in FIGS. 1 to 7. Is a square head 4 a having a rectangular cross section made of steel and joined to a pile head 3 a of an RC pile (concrete pile) 3 via a joining unit (steel footing) 5.

  For example, as shown in FIG. 9 (b), the RC pile 3 is formed by inserting a reinforcing bar assembly 7 into a drilled hole 44 formed in the ground by a drilling device 45 such as a screw auger at a predetermined position, and then applying concrete. It is called a cast-in-place concrete pile formed by placing. The joint unit 5 is joined to the concrete upper end portion of the RC pile 3 after the deteriorated portion having poor quality including air bubbles and impurities is removed. A large number of reinforcing bars 8 integrally extending from the reinforcing bar assembly 7 protrude upward from the vicinity of the outer periphery of the pile head 3 a of the RC pile 3. It has a length of minutes. However, the joining rebar 8 is arranged so that the web 11, the flange 12 and the extension plate 15 in the joining unit 5 can be installed sufficiently.

  The joining unit 5 includes a base structure 4b continuously formed on the base of the leg structure 4a of the square tube leg 4, a cylindrical steel shell 21 that is externally fixed to the outer periphery of the base structure 4b, The base structure 4b and the joining concrete 31 placed in the cylindrical steel shell 21 are configured.

  The base structure 4b of the square tube leg 4 is formed in a rectangular cross section by a pair of front and rear webs (outer plates) 11 and a pair of left and right flanges (outer plates) 12 which are integrally continuous from the leg structures 4a. Here, the width of the web 11 is formed so as to be wider than the flange 12, but a rectangular cross section in which the width of the flange 12 is wider than that of the web 11 may be used. Further, a plurality of reinforcing plate-like ribs 13 and 14 are provided on the inner surfaces of the web 11 and the flange 12 so as to protrude in the vertical direction. Further, the flange 12 is integrally provided with an extension plate (extension portion) 15 that protrudes outward from both side portions and has a tip portion connected and fixed to the inner surface of the cylindrical steel shell 21. These extension plates 15 connect the base structure 4b and the cylindrical steel shell 21 to integrally form the joining unit 5. The extension plates 15 may be provided from both sides of the web 11 instead of the flange 12, or Two extension plates perpendicular to each other may be formed by providing extension plates on both the flange 12 and the web 11 for each corner portion.

  A mounting base plate 17 is provided along the lower edge of the web 11 and the flange 12 to be seated on the pile head 3a of the RC pile 3 directly or via an installation block (for example, made of H-shaped steel). A partition plate 18 for partitioning the leg structure 4a and the base structure 4b corresponding to the upper end of the cylindrical steel shell 21 is attached, and an opening 18a is formed at the center thereof.

  Each of the web 11, the flange 12, the plate-like ribs 13 and 14, and the extension portion 15 is formed with a large number of anti-slip holes (perforated steel plate gibber: PBL) 16 at predetermined pitches. A load such as an axial force, a bending moment, and a shearing force is transmitted to the RC pile 3 via the bonding concrete 31. Transmission of the shearing force to the joining concrete 31 by these slip prevention holes 16 is more effectively performed by the cylindrical steel shell 21 that uniformly restrains the joining concrete 31 from the outer peripheral side.

  The features of the stopper hole 16 are as follows: a) Since the shear resistance per unit area is large, it is not necessary to install as many as the stud for preventing the slip, and the structure can be simplified. B) Fatigue durability And a structure to prevent slippage with sufficient toughness, c) a design method has been established, and it has been put on road bridges. Further, d) by forming the web 11 and the flange 12 constituting the square tube leg 4, it is possible to omit a stiffener for preventing the displacement, and e) directly applying the load of the detent to the square tube leg 4. It can be transmitted to the web 11 and the flange 12, and the transmission (flow) of the load or stress becomes clear, and the feature such as fatigue cracks occurring in the welded portion with the stiffener does not occur.

  In addition, by forming the stopper holes 16 in the web 11 and the flange 12 which are structural bodies, the rigidity of the square tube legs 4 may be reduced and the tensile strength of the steel sheet may be reduced. By appropriately selecting the diameter and the hole diameter, it is possible to prevent a decrease in the tensile strength of the steel sheet. Further, with respect to buckling, since the periphery of the joining concrete 31 is restrained by the cylindrical steel shell 21 and deformation is prevented, there is no problem as long as the joining concrete 31 is not destroyed. Of course, for the entire cross-section plasticity, the plate thickness of the web 11 and the flange 12 and the interval between the stopper holes 16 are set appropriately, and the hole cross section of the stopper holes 16 is determined.

  By the way, as shown in FIG. 12 (a), when the stopper b c is formed in the rib b attached to the main structure a, if the base material of the main structure a is considerably large and has high rigidity, the tensile load is increased. When loaded, the individual stopper holes c are evenly displaced as if they were on a rigid body, so that the individual stopper holes c can be designed on the assumption that they have approximately the same shear strength. it can. On the other hand, as shown in FIG. 12 (b), when the retaining holes e are formed in the steel sheet as the main structure d, when the tensile load is applied, the individual retaining holes are caused by the rigidity of the steel sheet. The displacement amount of e is different. As a result, the shearing force shared by each is different, and it is impossible to design that all the detent holes e share the shearing force equally. For example, when the main structure d is a steel plate and a plurality of retaining holes e are formed in the vertical direction, when an upward tensile force is applied to the main structure d, the shearing force supported by the retaining holes e is reduced from the load. The distribution becomes smaller as it goes downward. Since this distribution changes depending on the rigidity of the steel plate, the elastic modulus of concrete, and the like, it is necessary to perform an analysis in advance to confirm the shear strength.

  In order to increase the shear strength and fracture toughness, as shown in FIG. 5, a detent member (strength member) 19 is disposed in the upper detent hole 16 having a large shear force. For example, a reinforcing bar is used for the detent members 19 and is inserted between the detent holes 16 formed at positions facing each other in the horizontal direction so that a specific support jig is not required. Here, these anti-slip members 19 are arranged in the anti-slip holes 16 at the upper portions between the webs 11, between the flanges 12, between the ribs 13 and 13, between the ribs 14 and 14 and between the extension plates 15, respectively.

  The cylindrical steel shell 21 is formed to have the same or larger inner diameter as the pile head 3a of the RC pile 3, and a plurality of studs 22 for preventing concrete peeling in the radial direction are planted at predetermined intervals on the inner surface thereof. Has been.

  By the way, the anti-slip hole 16 has a high shear strength of 2 to 3 times compared to the anti-slip stud and exhibits excellent characteristics as anti-slipping performance. However, the anti-slipping hole 16 is formed to exhibit this performance. It is necessary to constrain the strain of the concrete 31 for bonding so as to prevent strain in the tensile direction to prevent tensile fracture at the boundary surface between the steel plate and the concrete, and to prevent split fracture of the concrete in the stopper hole 16. It is. For this reason, in this invention, the cylindrical steel shell 21 which can restrain concrete uniformly from outer peripheral part with a circular cross section is employ | adopted, and restraint effect compared with the hoop reinforcement etc. which are equipped in order to acquire restraint effect in RC pile etc. Is expensive. In addition, even if the rectangular steel shell 21 is enclosed in a rectangular cross section instead of the cylindrical steel shell 21, it is not possible to obtain a uniform restraining force of the concrete 31 for joining, and it is possible to ensure a sufficient shear strength by the detent hole 16. Can not.

  As shown in FIGS. 13 (a) and 13 (b), in the conventional socket foundation, the bearing pressure P acts dominantly between the pedestal U and the socket S to form a load-bearing structure. Since the base structure 4b and the cylindrical steel shell 21 are integrally connected and fixed via the extension plate 15, the cylindrical steel shell 21 is displaced substantially in accordance with the behavior of the base structure 4b. Therefore, a slight bearing pressure and peeling force between the cylindrical steel shell 21 and the base structure 4b are generated, but not so much as compared with the socket base.

  In order for the shearing force to be transmitted to the RC pile 3 through the joining concrete 31 by the displacement preventing holes 16 provided in the square tube legs 4, an adhesive force by a sufficient length of the connecting reinforcing bars 8 is necessary. This can also be obtained by calculation.

Next, an on-site construction method for this pier will be described with reference to FIGS.
1) After excavating the construction position, the earth retaining stand pipe 42 is installed at the construction position by using a lifting device such as a jib crane 41 [FIG. 9A].

  2) A small-diameter pile driving stand pipe 43 is installed in the soil retaining stand pipe 42, and a drilling hole 44 is formed in the ground from the pile driving stand pipe 43 by the drilling device 45 [FIG. b)].

  3) Insert and install the reinforcing bar assembly 7 in the drilling hole 44 [FIG. 9 (c)], remove the pile driving stand pipe 43, and cast concrete from the lower end of the soil retaining stand pipe 42 to a position above the predetermined height. It forms and forms RC pile 3 [Drawing 10 (d)].

4) After the deteriorated portion of the pile head 3a has been scraped [FIG. 10 (e)], the joining unit 5 is carried in together with the leg structure 4b, and the cylindrical steel shell 21 is externally fitted to the pile head 3a [FIG. ]].
In the figure, the base structure 4b is installed directly on the top surface of the pile head 3a via the installation base plate 17, but an installation block 46 made of H-shaped steel is provided between the base structure 4b and the pile head 3a. You may arrange. By this installation block 46, irregularities on the chipped surface of the pile head 3a can be absorbed.

  5) Joining from between the opening 18a and the base structure 4b of the partition plate 18 and the cylindrical steel shell 21 while holding the joining unit 21 at a predetermined height position with a jack or a supporting member to form the extra insertion portion 23. Concrete 31 for injection is poured and the RC pile 3 and the square tube leg are joined via the joining unit 5 [FIG. 11 (g)].

6) After backfilling, the stand pipe 42 is removed [FIG. 11 (h)].
According to Embodiment 1 above,
A. With a simple structure that does not use a conventional RC footing and anchor frame, the joining unit 5 that integrates the cylindrical steel shell 21 with the base structure 4b and the extension plate 15 allows for the formwork and bar arrangement work at the construction site. The construction period can be shortened compared to the conventional method, and the construction cost can be reduced.

  B. The cylindrical steel shell 21 uniformly restrains the joining concrete 31 of the joining unit 5 from the outer peripheral side, and the shear force is applied to the RC pile from the base structure through the joining concrete 31 by the large number of displacement preventing holes 16. Can be transmitted. Thereby, complicated structural members such as hoop rebars and studs that have been necessary in the past can be omitted, and by forming the stopper holes 16 directly in the web 11 and the flange 12 of the base structure 4b, the stopper holes 16 can be used. This rib can be eliminated, and the structure can be simplified and the cost can be reduced.

  C. By forming the anti-slip hole 16 in the web 11 or the flange 12 which is the outer plate of the base structure 4b, a difference occurs in the shearing force depending on the position of the anti-slip hole 16, but the shear force distribution is calculated and predicted in advance. By disposing the stopper member 19 made of a reinforcing bar in the stopper hole 16 to which a large shear force is applied, the shear strength can be further improved and the shear force can be effectively transmitted.

D. At the time of construction at the site, the extra insertion portion 23 is provided and the lower portion of the cylindrical steel shell 21 is externally fitted to the pile head 3a. Therefore, stress concentration due to sudden change in cross section can be reduced and horizontal shearing can be resisted.
FIG. 14 shows a modification of the first embodiment. In order to reduce accuracy during construction, the outer peripheral portion of the pile head 3a is scraped off by a height corresponding to the extra insertion portion 23 described later, and the step portion 9 is removed. Formed. By this step portion 9, play (margin) is formed between the pile head 3 a and the circular steel shell 21, facilitating the work of fitting the joining unit 5 to the pile head 3 a, and relaxing the dimensional accuracy during construction. Can do.

[Embodiment 2]
In the second embodiment, the pedestal is a cylindrical leg 51 having a circular cross section, and the same members are denoted by the same reference numerals and will be described with reference to FIGS. 15 to 20.

This joining portion joins the pile head 3 a of the RC pile (concrete pile) 3 and the steel cylindrical leg 51 having a circular cross section via a joining unit (steel footing) 52.
A base structure 51b provided at the base of the leg structure 51a of the cylindrical leg 51 includes a cylindrical outer plate 53 formed continuously with the cylindrical leg structure 51a, and an axial center within the cylindrical outer plate 53. The longitudinal inner reinforcing face plate 54 which is joined and crossed at 90 ° at the position, and four extension plates (extension portions) projecting radially from the outer face of the cylindrical outer plate 53 at an extended position continuous with the inner reinforcing face plate 54 ) 15 and a plurality of reinforcing plate-like ribs 55 projecting in the radial direction at a predetermined angle (30 ° in the figure) between the extension plates 15 on the outer peripheral surface of the cylindrical outer plate 53. .

  The joining unit 52 is placed in the base structure 51 b, the cylindrical steel shell 21 that is externally fitted to the base structure 51 b and connected and fixed via the extension plate 15, and the base structure 51 b and the cylindrical steel shell 21. It is comprised with the concrete 31 for joining. The extension plate 15 connects the base structure 51b and the cylindrical steel shell 21 to integrally form the joining unit 52.

  Further, along the lower edge of the cylindrical outer plate 53 and the longitudinal reinforcing face plate 54, there is provided an installation base plate 17 that is seated on the pile head 3a of the RC pile 3 directly or via an installation block (for example, made of H-shaped steel) 46. ing. A partition plate 18 having an opening 18a at the center is attached to the boundary between the leg structure 51a and the base structure 51b of the cylindrical leg 51 corresponding to the upper end of the cylindrical steel shell 21.

  The cylindrical outer plate 53, the inner reinforcing face plate 54, the plate-like rib 55, and the extension plate 15 are each formed with a large number of anti-slip holes (perforated steel plate gibber: PBL) 16 at predetermined pitches. The axial force, the bending moment and the shearing force are transmitted to the RC pile 3 via the joining concrete 31. Transmission of the shearing force to the joining concrete 31 by these slip prevention holes 16 is effectively performed by the cylindrical steel shell 21 that uniformly restrains the joining concrete 31 from the outer peripheral side.

  Further, in order to increase the shear strength and fracture toughness, the cylindrical outer plate 53, the inner reinforcing face plate 54, the plate-like rib 55, and the extension plate 15 have an anti-slip member (shear strength) in the upper detent hole 16 having a large shear force. (Reinforcing member) 19 is arranged. These detent members 19 are made of, for example, reinforcing bars, and are inserted between detent holes 16 formed at positions opposite to each other in the horizontal direction so as to be hung in a cross-beam shape, a radial shape, an arc shape or the like as shown in the figure. Does not require a specific support jig.

The construction procedure of the joint portion of the pedestal on the site can also be performed in the same procedure as in the first embodiment.
According to the second embodiment, the same effects as in the first embodiment are obtained.

It is a top view which shows Embodiment 1 of the junction part of the pedestal based on this invention. It is AA sectional drawing shown in FIG. 1 which shows the joining unit installation state of the junction part. It is CC sectional drawing shown in FIG. 2 which shows the joining unit installation state of the junction part. It is BB sectional drawing shown in FIG. 1 which shows the joining state of the junction part. It is a partial expansion perspective view which shows the same slip prevention hole and a slip prevention member. It is a perspective view which shows the joining unit which abbreviate | omitted the slip prevention member. It is a perspective view which shows the installation state of the joining unit. It is a general view which shows the viaduct which uses the junction part. (A)-(c) is explanatory drawing which shows the site construction procedure of the said junction part, respectively. (D)-(f) is explanatory drawing which shows the site construction procedure of the said junction part, respectively. (G) And (h) is explanatory drawing which shows the site construction procedure of the said junction part, respectively. (A) And (b) is explanatory drawing which shows the shear force of a slip prevention hole, respectively. (A) And (b) is explanatory drawing explaining the stress of the conventional socket foundation, respectively. FIG. 8 is a cross-sectional view taken along the line AA of FIG. 1 showing a modification of the first embodiment and showing a joint unit installation state of the joint portion. It is a top view which shows Embodiment 2 of the junction part of the pedestal based on this invention. It is EE sectional drawing shown in FIG. 15 of a joining unit installation state. It is FF sectional drawing shown in FIG. It is GG sectional drawing shown in FIG. It is EE sectional drawing shown in FIG. 15 of the concrete filling state for joining. It is HH sectional drawing shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 RC pile 3a Pile head 4 Square tube leg 4a Leg structure 4b Base structure 5 Joining unit 8 Joining rebar 9 Step 11 Web 12 Flange 13, 14 Rib 15 Extension plate 16 Slip hole 17 Installation base plate 19 Slip stopper Member 21 Cylindrical steel shell 22 Stud 23 Extra portion 31 Concrete for joining 51 Cylindrical leg 51a Leg structure 51b Base structure 52 Joining unit 53 Cylindrical outer plate 54 Inner reinforcing face plate 55 Rib

Claims (8)

A joint structure of a pedestal that connects a pile head of a concrete pile and a base of a steel cylindrical leg,
To the base structure of the cylindrical leg, an extension projecting on the outer plate of the base structure, a reinforcing bar protruding upward from the pile head, the base structure and the reinforcing bar Provided with a joining unit comprising a cylindrical steel shell that is externally fitted and connected and fixed to the base structure through the extension, and restrains the outer periphery of the joining concrete to be placed inside;
A pedestal joint structure in which a large number of slip holes for transmitting shearing force from the base structure to the pile head are formed on at least the outer plate of the base structure via the joining concrete. The cylindrical leg is a rectangular tube leg with a rectangular cross section,
The limbal joint structure according to claim 1, wherein the extension portion is formed by extending from the outer plate of the base structure. The cylindrical leg is a cylindrical leg with a circular cross section,
The extension structure protrudes in the radial direction from the outer plate of the base structure. An extra insertion part is provided in which a cylindrical steel shell is externally fitted downward from the top of the pile head.
The junction structure of the pedestal according to any one of claims 1 to 3, wherein a slip prevention hole is formed in each of the reinforcing rib and the extension of the base structure. The junction structure of the pedestal according to any one of claims 1 to 4, wherein a detent member is disposed in a detent hole in a portion having a large shearing force applied to the base structure. When connecting the base of a steel cylindrical leg to the pile head of a concrete pile,
A cylindrical steel shell that is externally fitted to the base structure via an extension protruding from the outer plate of the base structure is attached to the base structure of the cylindrical leg in which a large number of slip prevention holes are formed in the outer plate. Attach the fixed unit
A cylindrical leg is arranged on the pile head via the joining unit, and a joining rebar protruding from the pile head is contained in the cylindrical steel shell,
Placing the joining concrete in the cylindrical steel shell to join the pile head and the cylindrical leg,
A joining method of pedestals in which the concrete for bonding is uniformly restrained by the cylindrical steel shell and shear force is transmitted from the base structure to the pile head via the detent hole. At the time of attaching the joining unit, an extra insertion part is formed to externally fit the cylindrical steel shell downward from the top of the pile head,
The joining method of the pedestal according to claim 6, wherein an anti-slip member is disposed in an anti-slip hole in a portion to which a large shear force is applied. The pedestal according to claim 7, wherein when the joining unit is fitted to the pile head, the outer circumference of the pile head at least the height of the extra portion is reduced to make the pile head smaller than the inner diameter of the cylindrical steel shell. Joining method.

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