JP2008014118A - Low fixing degree pile head joint structure with bearing body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low fixing degree pile head joint structure capable of controlling rotational rigidity of a pile head and resisting horizonal force, push-in force and bending moment while ensuring aseismatic safety in basic constitution of joining a pile and a foundation slab by a reinforcement. <P>SOLUTION: In joining the pile and the foundation slab 4 constructed at the upper part of the pile, the low fixing degree pile heat joint structure is formed by welding one end of the reinforcement anchored into the foundation slab to a steel pipe side face of the pile head 1 from a position lowered by a predetermined length from the upper end of the pile without embedding the pile head 1 in the foundation slab, to form a non-welded reinforcement extensible part 15 outside the foundation slab to thereby permit control of rotational rigidity of the pile head and the moving amount of the pile head while resisting all the stress generated to the pile head with the reinforcement, a horizontal bearing body 11 close to the reinforcement, and a vertical bearing body 12 abutting on the upper end 2 of the pile. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a low-fixation pile head joint structure having a bearing body.

    In recent years, various low-fixation joining techniques have been developed for the purpose of reducing the bending moment generated in the pile head by making the pile head easy to rotate. For low-fixed joints between general piles and foundation slabs, there are joints in which unbonded anchors or dampers with damper material attached to the pile heads by welding etc. are embedded in the foundation slabs, and joints in which rings and caps are put on the pile heads. There is.

Problems to be solved by the invention

    The method to reduce the degree of fixation of the pile head by embedding unbonded reinforcing bars or dampers with damper material attached to the pile head in the foundation slab is to insulate the adhesion between the reinforcing bars and the foundation slab concrete with unbond and damper. There is a method to make it easier to rotate the pile head by increasing the expansion and contraction of the reinforcing bar, and there are a method in which the pile head is embedded in the foundation slab and a method in which the pile head is not embedded in the foundation slab. According to the test results of the Ministry of Construction, etc., it has been reported that the degree of fixing when the pile head is embedded in the foundation slab is about 80%. The pile head joint structure is very unlikely to be expected, and the possibility that the lever reaction caused by the rotation of the pile head in response to the expansion and contraction of the unbond anchor will cause local brittle fracture in the concrete in the embedded part of the side of the pile head. I can say that. The latter method, which does not embed the pile head, must transmit the horizontal force acting on the pile head to the foundation slab concrete not by the side of the pile head but only by the side bearing of several pile head rebars with a small cross-sectional area. The horizontal force cannot be transmitted sufficiently, and there is a risk of bearing failure in the concrete on the side of the anchor.

    In order to expand and contract the reinforcing bars fixed in the foundation slab, unbonding and dampers that insulate the adhesion between the foundation slab concrete and the reinforcing bars, and a fixing body for securing the fixing force are required. The arrangement of the bar arrangement with the base muscles is complicated and takes time and money.

    The method of covering the pile head with the ring and cap to reduce the fixing degree of the pile head is not connected to the ring and cap and the pile, so it can not be used for piles with pulling force acting on the pile head, Seismic safety is extremely low because of its pin joint behavior with large horizontal displacement and low static order.

Means for solving the problem

    In this invention, this invention solves the said problem by having developed the low fixed degree pile head junction structure which has a bearing body.

The invention's effect

    The present invention according to the present invention has the following specific effects in the low-fixation pile head joint structure having a support body.

    By combining the pile head joint rebar and the bearing body, all the stress generated in the pile head, that is, the bending moment is treated as the tensile and compressive force of the reinforcing bar, and the vertical bearing body is applied to the pushing force. The load transmission mechanism treats the horizontal force acting on the pile as the bearing pressure of the foundation slab concrete via the horizontal bearing body against the shear force borne by the reinforcing bar. Can be formed.

    Pile that enables reliable and stable control of rotational rigidity by adjusting the stretchability of non-welded rebar extendable parts and non-threaded rebar extendable parts without embedding the pile head in the foundation slab A head rotating spring mechanism can be formed.

    Since the basic structure of the high-fixation pile head joint structure in which the pile and the foundation slab are joined by reinforcing bars is maintained, the static destabilization order is high and seismic safety is ensured.

    By welding the lower end of the reinforcing bar to the ring plate welded to the side surface of the steel pipe, it is possible to form an integral structure that can resist the eccentric bending moment generated at the welded part of the reinforcing bar.

    Here, one Example of the low fixed degree pile head joint structure which has the bearing body of this invention is described based on drawing.

    FIG. 1 is an elevational view of a low-fixation pile head joint structure according to the invention of claim 1. In this embodiment, one end of the reinforcing bar 3 fixed to the foundation slab 4 is brought into contact with a ring plate 23 welded to the periphery of the side surface of the steel pipe 7 in advance, and from a position lower than the pile upper end 2 by a predetermined length, The steel pipe pile 6 is welded to the side surface of the steel pipe 7 at the pile head 1 and the ring plate 23 to form a non-welded rebar stretchable portion 15 outside the foundation slab 4, and a cylinder close to the inside of the rebar 3. The example which has arrange | positioned the vertical horizontal bearing body 11 and the vertical bearing body 12 which contact | abutted to the pile upper end 2 is shown. A reinforcing member 13 is disposed inside the horizontal bearing body 11 and above the vertical bearing body 12, but the horizontal bearing body 11 is placed close to the outside of the reinforcing bar 3 and the vertical bearing inside the reinforcing bar 3. The pressure member 12 may be disposed separately from the pressure member 12, and the reinforcing member 13 may be disposed below the vertical bearing member 12. Although the vertical bearing body 12 is shown as an example of a single-layer planar steel plate, in order to adjust the rotational rigidity of the pile head 1, the steel plate is processed into a curved surface or the upper or lower portion of the vertical bearing body 12. There is also a method of implementing a two-layer structure in which different materials such as rubber are interposed between the foundation slab 4 or the pile head 1. In order to weld the rebar 3 to the side surface of the steel pipe 7, the excavation part 19 at the lower part of the foundation slab excavating a part of the side surface of the steel pipe 7 forms a gap or extends and contracts the rebar extension part 15. The structure is surrounded by a material such as sand or foaming agent that does not interfere. Although the pile head 1 is not embedded in the foundation slab 4 and the pile upper end 2 and the foundation slab bottom surface 5 are in the same position, there is a case where the pile upper end is slightly moved up and down with respect to the foundation slab bottom.

    FIG. 2 is a cross-sectional view taken along line AA of FIG.

    FIG. 3 is a cross-sectional view taken along the line BB of FIG.

    FIG. 4 is an elevational view of a low-fixation pile head joint structure according to the inventions of claims 2 and 4. In this embodiment, the male screw 10 at one end of the reinforcing bar 3 fixed to the foundation slab 4 is screwed into the female screw 22 on the upper surface of the end steel member 16 at the pile head 1 of the steel pipe-wrapped concrete pile 8 and screwed. After inserting the steel plate 21 having a round hole into which the reinforcing bar 3 is inserted, the steel plate 21 is sandwiched between the end steel member 16 with the nut 20 and screwed into the male screw 10 of the reinforcing bar 3 and tightened. An example in which a non-threaded reinforcing bar extendable portion 25 is formed on the upper part of the steel member 16 and a horizontal bearing body 11 close to the inside of the steel plate 21 and a vertical bearing body 12 in contact with the pile upper end 2 are arranged. Is shown. In addition to the above, for joining the reinforcing bar 3 fixed to the foundation slab 4 and the end steel member 16 of the pile head 1, the male screw 10 at one end of the reinforcing bar 3 is connected to the female screw 22 on the upper surface of the end steel member 16 of the pile head 1. Directly screwed or after the male screw 10 at one end of the reinforcing bar 3 is screwed into the female screw 22 on the upper surface of the end steel 16 of the pile head 1, the nut 20 is screwed into the male screw 10 of the reinforcing bar 3 and tightened. There is also a method of joining to 2. Further, the horizontal bearing body 11 may be arranged in the vicinity of the outside of the steel bar 21 having the reinforcing bar 3, the nut 20, or the round hole and separated from the vertical bearing body 12 inside the reinforcing bar 3.

    FIG. 5 is a cross-sectional view taken along line AA of FIG.

    FIG. 6 is an elevational view of a low-fixation pile head joint structure according to the invention of claim 3. In this embodiment, one end of the reinforcing bar 3 fixed to the foundation slab 4 is joined to the upper surface of the end steel member 16 on the pile head 1 of the steel pipe-wrapped concrete pile 8 by the stud welding 24 and is connected to the outside of the reinforcing bar 3. The structure which has arrange | positioned the horizontal bearing body 11 adjacent is shown. In order to remarkably reduce the rotational rigidity, it is possible to use a fixing body provided at the end of the reinforcing bar 3 and a sheath that surrounds the surface of the shaft portion and insulates the adhesion with the concrete.

    FIG. 7 is a cross-sectional view taken along line AA of FIG.

    It is an elevation view of the low fixed degree pile head joint structure which has a bearing body which concerns on invention of Claim 1.

    It is a cross-sectional view by the AA line of FIG.

    It is a cross-sectional view by the BB line of FIG.

    It is an elevation view of the low fixed degree pile head joint structure which has a bearing body which concerns on invention of Claim 2 and 4.

    It is a cross-sectional view by the AA line of FIG.

    It is an elevation view of the low fixed degree pile head joint structure which has a bearing body which concerns on invention of Claim 3.

    It is a cross-sectional view by the AA line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pile head 2 Pile top 3 Pile head joint reinforcement 4 Foundation slab 5 Bottom surface of foundation slab 6 Steel pipe pile 7 Steel pipe 8 Steel pipe winding concrete pile 9 Concrete part of steel pipe winding concrete pile 10 Male thread of pile head joint reinforcement 11 Horizontal bearing body 12 Vertical bearing body 13 Reinforcement material of bearing body 14 Welded part of steel pipe side and pile head joint rebar 15 Unwelded rebar extendable part 16 End steel material provided at pile head 17 Pile head joint rebar 18 Pile Groove of head joint rebar 19 Excavation part under foundation slab 20 Nut 21 Steel plate with round hole to insert rebar 22 Internal thread of end steel 23 Ring plate 24 Welded part of end steel and stud rebar 25 Non-stiff Reinforcing bar extendable part

Claims (4)

      In joining the pile to the foundation slab constructed on the top, weld one end of the reinforcing bar that is anchored in the foundation slab to the steel pipe side of the pile head from a position that is lower than the pile upper end by a predetermined length. A low-fixed pile head joint structure characterized in that a non-weld rebar stretchable part is formed on the top and a horizontal bearing body close to the reinforcing bar and a vertical bearing body that abuts on the upper end of the pile are arranged.       In joining the pile and the foundation slab constructed on the top, one end of the reinforcing bar fixed in the foundation slab is joined to the upper surface of the end steel material provided on the pile head by screwing or welding, and this reinforcing bar or A low-fixed pile head joint structure characterized by arranging a horizontal bearing body close to the inside or outside of a nut or the like that fixes the reinforcing bar and a vertical bearing body that abuts the upper end of the pile.       In joining the pile and the foundation slab constructed on the top, one end of the reinforcing bar fixed in the foundation slab is joined to the upper surface of the end steel material provided on the pile head by screwing or welding, and this reinforcing bar or Low-fixed pile head joint structure characterized by arranging horizontal bearings close to the inside or outside of nuts etc. that fix the reinforcing bars.       A male screw at one end of the reinforcing bar fixed in the foundation slab in the threaded engagement between the reinforcing bar fixed in the foundation slab according to claim 2 and the end steel material provided on the pile head and the horizontal bearing body. Is inserted into the female screw of the end steel material, and a steel plate having a round hole is inserted into the screwed rebar, and then the steel plate having the round hole is screwed onto the male screw of the rebar from above and tightened. A low-fixation pile characterized in that a non-threaded rebar extendable part is formed on the upper part of the end steel material and a horizontal bearing body is arranged close to the inside or outside of the steel plate having this round hole. Head joint structure.

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