JP4783746B2 - Joint structure of slant pile and foundation - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a joint structure between a slant pile and a foundation which are joined to a foundation of a pile head by fixing a pile main reinforcement arranged inside a slant pile to the foundation.

  The slant pile driven in the direction inclined with respect to the vertical has the advantage of being able to resist the load in the horizontal direction in addition to the load in the vertical direction. In many cases, it is used for the purpose of stabilization. Depending on the application location, the diagonal piles may be used alone or in combination, but in either case, the diagonal pile heads need to be joined to the foundation by some means.

  For example, if it is attempted to fix the pile main bar arranged in the pile body to the foundation, the pile main bar will be arranged at an angle with respect to the vertical and horizontal bars in the foundation. It is easy to interfere with the streak and the horizontal streak, and it becomes difficult to connect to the vertical streak by a lap joint or the like.

  If you place a steel pipe that surrounds the head of the slant pile and place a joint reinforcement between the slant pile and the steel pipe, you can solve the problem of the reinforcement of the pile main bars that are arranged in the slant pile. It can be avoided (see Patent Document 1).

JP 2000-248526 A (Claim 2, paragraphs 0008, 0019 to 0020, FIG. 13)

  However, since the steel pipe in Patent Document 1 needs to have an inner diameter that can surround the head of the inclined pile with the axis oriented vertically, it needs to have an inner diameter that is about twice the outer diameter of the inclined pile. The construction cost will increase and the construction will be large. In addition, it is necessary to arrange a joint rebar as a means of transmitting tensile force after joining the stopper to ensure the integrity with the concrete filled in the steel pipe on the outer peripheral surface of the slant pile, The structure of the joint is complicated.

  The present invention proposes a joint structure between a slant pile and a foundation that simplifies the structure of the joint while avoiding interference between the pile main reinforcement and the reinforcing bar in the foundation.

The inclined pile and foundation joint structure of the invention according to claim 1 is a pile that has been driven in the field and that has at least a hollow head and a pile that extends to the foundation and is arranged inside the pile. A main reinforcement, concrete placed on the foundation, and filling concrete cast on a hollow portion of the pile, the filling concrete and the foundation concrete are integrated, and the pile is vertically It is a slant pile driven at an angle with respect to the direction, and the pile main bar extends in the vertical direction from the inside of the pile and is arranged in the foundation .

  Since the pile main reinforcement is arranged between the head and the foundation of the diagonal pile, there is no need to separately arrange members such as steel pipes for joining around the diagonal pile, thus suppressing an increase in construction costs. As a result, the structure of the joint is simplified. In addition, since the reinforcing bars that join the diagonal pile and the foundation are arranged inside the diagonal pile, it is not necessary to increase the diameter of the diagonal pile body in order to surround all the main pile bars.

  Furthermore, because the pile main bars are arranged vertically or close to it, interference with the vertical and horizontal bars arranged in the foundation is less likely to occur, so the connection between the pile main bars and the vertical bars and the pile main bars It is possible to arrange the horizontal stripes by sewing between the gaps.

  In particular, in the case where a horizontal transition section having a polygonal cross section is formed between the head of the slant pile and the foundation as described in claim 2, As described, the pile main bars are arranged in a polygonal shape as a whole along the outer shape of the transition portion at the transition portion, which improves. In this case, since a fixed interval is secured between the pile main bars in the circumferential direction of the pile main bars, interference between the horizontal bars and the pile main bars that are arranged by sewing between the pile main bars is avoided.

  When pile main bars are arranged in a circular shape along the cross section of the pile, the projected length to the vertical plane of the interval between adjacent pile main bars is the largest on the circular diameter, and away from the diameter position The smaller it becomes. Since the transverse bars in the foundation are arranged in two directions orthogonal to the circle which is the cross section of the pile, the transverse bars arranged at a position far from the diameter position hardly pass between the pile main bars. As a result, there is a situation in which the horizontal bars cannot be arranged due to the presence of a slight construction error, and the pile main bars or the horizontal bars may be forced to bend.

  On the other hand, since it is possible to secure a constant interval between the pile main bars in the circumferential direction of the pile main bars by arranging along the outer shape of the transition part in which the pile main bars have a polygonal shape in claim 3, Interference between the horizontal bars and the pile main bars that are laid out between the pile main bars is avoided. By arranging the pile main bars in a polygonal shape, the projection length on the vertical plane of the interval between adjacent pile main bars can be made equal. In addition to avoiding interference, the horizontal bar arrangement workability is improved.

  In many cases, the slant pile main body has a circular cross section because of the relation of being inserted into the drilling hole or the relation of directly press-fitting the slant pile main body. On the other hand, in Claim 2, since the transition part which is a joint part with a foundation is polygonal shape, directionality arises in the resistance of the transition part with respect to the bending moment which acts on a slant pile main body, and a relative weak axis Therefore, it is easier to form a hinge than when it is circular.

  The transition part is formed in the section from the head to the foundation of the diagonal pile, and surrounds the pile main reinforcement that is vertically arranged. Therefore, the cross-sectional area (horizontal cross-sectional area) of the transition part is that of the diagonal pile body excluding the transition part. It becomes smaller than the cross-sectional area. As a result, since the strength of the transition portion is relatively lower than the strength of the diagonal pile body, a hinge is easily formed in the transition portion between the foundation and the diagonal pile body. In addition to reducing the bending moment acting on the transition part due to the formation of the hinge, it is possible to avoid the situation of damaging the foundation even if it causes rotational deformation to the foundation when the slant pile body is a steel pipe Become.

  There are reinforced concrete piles, steel pipe piles, PHC piles, etc., including prefabricated piles and cast-in-place concrete piles. Become reinforced concrete.

Because the transition part protrudes from the diagonal pile body to the foundation side, as described above, it becomes reinforced concrete regardless of the structure of the oblique pile body, so the diagonal pile body is damaged when it receives high axial force from the foundation, Or it is assumed to be destroyed. Therefore, even when damage or the like occurs in the transition part, in order to prevent the settlement from occurring in the foundation, as described in claim 4, at least one of the inner peripheral side and the outer peripheral side of the pile main bar , A main bar restraining material arranged in the same square as the array shape of the pile main bars is arranged along the outer periphery of the transition part .

  The main bar restraining material restrains the pile main bar from the inner or outer circumferential side, restrains the pile main bar from protruding and concrete protrusion due to the axial compressive force, suppresses the shrinkage of the transition part, and subsidizes the foundation. Suppress.

  In order to arrange multiple pile main bars that span between the head of the diagonal pile and the foundation and have sufficient anchorage length in the diagonal pile and in the foundation, separate members for joining around the diagonal pile There is no need to dispose, and the structure of the joint can be simplified.

  Also, because the pile main bars are arranged vertically or close to it, interference with the vertical and horizontal bars arranged in the foundation is less likely to occur. It is possible to improve the workability of the horizontal bars by sewing between the pile main bars.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows a crossing between the head of the inclined pile 1 and the foundation 6 at the joint between the inclined pile 1 and the foundation 6 to which the inclined pile 1 is joined, and a sufficient fixing length in the inclined pile 1 and the foundation 6. The specific example of the junction structure of the slant pile and foundation in which the multiple pile main reinforcement 3 which has is arranged is shown. 2- (a), (b), and (c) show cross sections taken along lines AA, BB, and CC in FIG.

  Although FIG. 1 shows the case where the diagonal pile 1 is a steel pipe pile or a steel pipe concrete pile in which concrete is filled in the steel pipe, the diagonal pile 1 may be a reinforced concrete structure. A plurality of pile main bars 3 are arranged in the vertical direction or close to the inside of the slant pile 1, and shear reinforcement bars 4 such as hoop bars and spiral bars are arranged around the pile main bars 3. When the diagonal pile 1 is a steel pipe pile, at least the pile main reinforcement 3 in the head section of the diagonal pile 1 has a concrete section so that the load is transmitted between the main pile 6 and the basic pile 6 through the pile main reinforcement 3. 1b is filled.

  In the drawing, the pile main reinforcement 3 is arranged only in the section from the position near the head of the oblique pile 1 to the middle of the foundation 6, but the reinforcement may be arranged along the entire length of the oblique pile 1. In that case, the pile main reinforcement 3 is bent in the middle of the length direction in order to avoid a collision with the inner peripheral surface of the oblique pile 1. In order to secure a sufficient anchorage length in the diagonal pile 1 without arranging the pile main reinforcement 3 over the entire length of the diagonal pile 1, the pile main reinforcement 3 is bent in the middle of the length direction as shown in FIG. And extended in the axial direction of the diagonal pile 1. A plurality of pile main bars 3 are assembled together with shear reinforcement bars 4 as reinforcing bar rods, and main bar restraining members 5 described later are also integrated with the reinforcing bar rods.

  The horizontal section of the transition part 2, which is the region surrounding all the pile main bars 3, is a diagonal pile because the all pile main bars 3 are arranged so as to straddle the diagonal pile 1 and the foundation 6 while being arranged substantially vertically. It becomes smaller than the cross section of one main body. The pile main reinforcement 3 is perpendicular to the bottom surface of the foundation 6 and is inclined with respect to the axis of the inclined pile 1.

  Since the horizontal cross section of the transition portion 2 is smaller than the cross section of the slant pile body 1, the transition portion 2 yields due to the bending moment acting on the slant pile body 1, and it is easy to form a hinge, so that it is easy to absorb energy during an earthquake There are advantages. If the transition portion 2 yields prior to the main body of the diagonal pile 1 and a hinge is formed on the transition portion 2, the possibility that the inclined main body 1 is damaged by a bending moment decreases. Further, since the transition part 2 protrudes from the inclined pile 1 main body toward the foundation 6 side, it becomes possible to keep the inclined pile main body 1 and the foundation 6 healthy even when the inclined pile 1 undergoes rotational deformation with respect to the foundation 6. ing.

  When it is going to form the hinge in the transition part 2, from the relationship which suppresses the bending deformation ability of the transition part 2, the height of the transition part 2, ie, the distance from the top of the slant pile 1 main body, to the bottom face of the foundation 6 is the pile diameter. Is about 1/5 to 1/10.

  When the oblique pile 1 is a steel pipe concrete pile, a protrusion 1c is provided on the inner peripheral surface of the steel pipe 1a to ensure adhesion with the concrete 1b and to suppress the deviation and separation of the steel pipe 1a and the concrete 1b. The protrusion 1c is provided in a ring shape so as to circulate in the circumferential direction of the steel pipe 1a and partially project in the circumferential direction.

  The transition part 2 protrudes from the main body of the diagonal pile 1 to the foundation 6 side and corresponds to a part of the pile head that connects the oblique pile 1 main body and the foundation 6. The transition portion 2 is a cross-sectional view taken along the line AA of FIG. 2 because it is easy to arrange the horizontal bars 7 arranged in the foundation 6 and easy to form a hinge to the transition portion 2 itself. As shown to (a), it forms in polygonal horizontal cross sections, such as a square shape.

  The horizontal section of the transition portion 2 is basically formed in a square shape or a rectangular shape as shown in FIG. 3A in arranging the pile main bars 3 equally in the two horizontal directions. In FIG. 2, since it is sufficient that a certain degree or more of fog is secured on the reinforcing bar (shear reinforcing bar 4) located on the outermost peripheral side, an octagonal or other polygonal shape is formed as shown in FIG.

  For example, after the construction of the main body of the slant pile 1 or the insertion (press-fit) into the drilling hole, the transition part 2 forms a frame around the pile main reinforcement 3 including the shear reinforcement 4 before the foundation 6 is constructed, and the concrete foundation It is constructed by placing 6 at the same time.

  The plurality of pile main bars 3 are arranged in a polygonal shape along the outer shape of the transition portion 2. In FIG. 1 and FIG. 2, the pile main reinforcement 3 is double arranged and the square steel tubular main reinforcement restraining material 5 is arranged on the inner circumference of the pile main reinforcement 3 on the inner circumference side. As shown in FIG. 3, it is sufficient to arrange the bars in a single line along the outer periphery of the transition portion 2. When the bars are double arranged, the pile main bars 3 on the inner peripheral side of the pile main bars 3 are also arranged in a polygonal shape. The main bar restraint material 5 may be disposed on the outer periphery of the pile main bar 3 on the outer peripheral side.

  When the pile main bars 3 are doubled, the horizontal bars 7 can be inserted between the pile main bars 3 and 3 adjacent to each other on the plane and in the circumferential direction in both the outer and inner pile main bars 3. An interval is secured. Even in the case of a single layer, an interval in which the horizontal bar 7 can be inserted between the adjacent pile main bars 3 and 3 is secured.

  When the pile main bars 3 are double, the interval between the adjacent pile main bars 3 and 3 on the inner peripheral side and the interval between the adjacent pile main bars 3 and 3 on the outer peripheral side are as shown in FIG. Is secured at the same or substantially the same position. In the drawing, in addition to the pile main bars 3 and 3 adjacent to each other in the circumferential direction, the distance between the pile main bars 3 and 3 so that the horizontal bars 7 can be inserted between the pile main bars 3 on the inner peripheral side and the pile main bars 3 on the outer peripheral side. Is adjusted.

  In addition to a closed cross-section material such as a steel pipe, a hoop bar or a spiral bar is used for the main bar restraining member 5, and the pile main bar 3 (rebar bar) is integrated by welding or the like. The pile main reinforcement 3 and the main reinforcement restraining material 5 are continuous from the main body of the oblique pile 1, and a sufficient fixing length is taken in the foundation 6. In the case of FIGS. 1 to 3 in which the pile main bars 3 are arranged in a single layer, the shear reinforcing bars 4 also serve as the main bar restraining material 5.

  By placing the main bar restraining material 5 on the inner circumference or outer circumference of the pile main bar 3, high axial compression force from the foundation 6 acts on the main body of the diagonal pile 1 and the concrete of the transition part 2 can be damaged or destroyed. Even when there is a property, the main bar restraining material 5 can restrain the deformation of the pile main bar 3. Since the protrusion of the concrete is suppressed by the restraint of the pile main bars 3, there is an advantage that the settlement of the foundation 6 can be suppressed.

  The main bar constraining material 5 functions to constrain the pile main bar 3 from protruding by the axial compressive force by constraining the pile main bar 3 from the inner peripheral side or the outer peripheral side. When the concrete of the transition part 2 loses the compressive resistance, the function of bearing the axial compressive force is also exhibited. The subsidence suppression effect of the foundation 6 can also be obtained by exerting the ability to bear the axial compression force.

  As shown in FIG. 4 which is a bar arrangement diagram of FIG. 1, the horizontal bars 7 arranged in the foundation 6 are arranged in a lattice pattern and are arranged in two directions so as to sew between adjacent pile main bars 3 and 3. . As shown in the drawing, even if the pile main bars 3 are double arranged, the pile main bars 3 on the inner peripheral side and the outer peripheral side are arranged in a polygonal shape, so that the horizontal bars 7 do not interfere with the pile main bars 3. Arranged. 5 is a sectional view taken along the line DD of FIG. 4, and FIG. 6 is a sectional view taken along the line EE. In FIG. 4, 8 shows a shear reinforcement.

  As shown in FIG. 4 to FIG. 6, the distance between adjacent pile main bars 3 and 3 is constant regardless of whether the transition part 2 is near the center or the outer periphery. Regardless of the position of the pile main bar 3, the bars are freely arranged between the pile main bars 3 and 3.

It is the longitudinal cross-sectional view which showed the detailed example of the junction part of a diagonal pile and a foundation. (A) is the sectional view on the AA line of FIG. 1, (b) is the sectional view on the BB line, (c) is the sectional view on the CC line. (A) is a horizontal cross-sectional view showing the relationship between the cross-section of the transition portion and the cross-section of the slant pile body when the transition portion is rectangular, and (b) is the cross-section of the transition portion when the transition portion is octagonal. It is the horizontal sectional view which showed the relationship of the cross section of a slant pile main body. It is the top view which showed the relationship between the horizontal bar in a foundation, and a pile main bar. It is the DD sectional view taken on the line of FIG. It is the EE sectional view taken on the line of FIG. It is a longitudinal cross-sectional view which shows the example of the arrangement | positioning of a pile main bar in the case of ensuring sufficient fixing length in a diagonal pile, without arranging a pile main bar to the full length of a diagonal pile.

Explanation of symbols

1 ……… Slant pile 1a …… Steel pipe 1b …… Concrete 1c …… Protrusion 2 ………… Transition part 3 ………… Pile main reinforcement 4 ……… Shear reinforcement 5 ……… Main reinforcement restraint 6 ……… Base 7 ……… Horizontal reinforcement 8 ……… Shear reinforcement

Claims (4)

A pile piled at the site, with at least a hollow head,
Pile main bars that are arranged inside the pile and extend to the foundation;
Concrete placed on the foundation;
Comprising filled concrete cast in the hollow portion of the pile,
The filling concrete and the concrete of the foundation are integral,
The pile is an oblique pile driven obliquely with respect to the vertical direction,
The pile head reinforcing bar extends in the vertical direction from the inside of the pile and is arranged in the foundation.   The inclined pile-foundation joint structure according to claim 1, wherein a transition portion having a polygonal horizontal cross section is formed between the head and the foundation of the oblique pile.   3. The diagonal pile-foundation joint structure according to claim 2, wherein the pile main bars are arranged in a polygonal shape as a whole along the outer shape of the transition portion at the transition portion. The main bar restraint material arranged in the same square as the array shape of the pile main bars is arranged along the outer periphery of the transition portion on at least one of the inner peripheral side and the outer peripheral side of the pile main bars. The slant pile-foundation joint structure according to claim 2 or 3 .

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