JP2014194121A - Pile head joint structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pile head joint structure, capable of effectively reinforcing a joint part of a pile head part of a foundation pile and base concrete, capable of also using a reinforced bar composed of a weldability-undesirable material, capable of reducing the number of reinforced bar, and capable of eliminating overcrowding bar arrangement above the pile head part.SOLUTION: The pile head joint structure 40 is provided for integrally joining the foundation pile 44 and the base concrete 48 via the reinforced bar 46 by embedding the pile head part 44a of the foundation pile 44 in the base concrete 48, and comprises a plurality of joint members 42 for joining a lower end part of the reinforced bar 46. The plurality of joint members 42 are joined at an interval to an outer peripheral surface 44b of the pile head part 44a, and the length in the direction corresponding to the circumferential direction of its pile head part 44a, is longer than the length in the direction corresponding to the radial direction of its pile head part 44a.

Description

  The present invention relates to a pile head joint structure used for a joint portion between a pile head of a foundation pile such as a steel pipe pile or an SC pile and a foundation concrete portion of a building.

  Conventionally, as a pile head joint structure used for a joint between a pile head of a foundation pile such as a steel pipe pile or an SC pile (concrete pile with shell steel pipe) and a foundation concrete portion of a building, the pile head of the foundation pile Some have welded reinforcing bars to the outer peripheral surface of the part (see Patent Document 1).

  FIGS. 11 to 13 are views referred to for explaining the conventional pile head joint structure 2.

  As shown in FIG. 11, the conventional pile head joint structure 2 has a steel pipe pile 4 having a pile head 4a at its upper end, a plurality of reinforcing reinforcing bars 6, and foundation concrete 8 placed around these steel piles. It was configured with.

  The steel pipe pile 4 was formed in a cylindrical shape (see FIG. 12) having a shaft hole extending in the vertical direction in the figure, and its lower end was deeply embedded until it hits a hard place in the foundation ground 3. Further, the upper end portion of the steel pipe pile 4 protrudes upward from the upper surface of the foundation ground 3, and the upper end portion is a pile head 4 a of the steel pipe pile 4.

  On the outer peripheral surface 4b of the pile head 4a, the lower ends of a plurality of reinforcing bars 6 in the form of a round bar extending in the length direction of the steel pipe pile 4 are integrated by welding the welded portion W (see FIG. 12). Were joined. Further, as shown in FIG. 12, the plurality of reinforcing reinforcing bars 6 are arranged so that the length direction thereof is along the length direction of the outer peripheral surface 4b of the pile head 4a, and the cross section is a circle of the outer peripheral surface 4b. The length directions were arranged in parallel with each other at intervals in the circumferential direction.

  Then, as shown in FIG. 11, the foundation concrete 8 is placed around the foundation ground 3 so as to embed the pile head 4a of the steel pipe pile 4 and the reinforcing reinforcing bars 6 on the foundation ground 3 to reinforce them. It was formed in a substantially rectangular parallelepiped shape having an upper surface at a position higher than the height position of the upper end of the reinforcing bar 6.

  Such a conventional pile head joint structure 2 has a pile head 4a of the steel pipe pile 4 and a pile head when an earthquake force F and a bending moment M as shown in FIG. The basic concrete 8 in contact with the upper end surface 4c of 4a, the reinforcing reinforcing bars 6 and the basic concrete 8 in contact with the reinforcing reinforcing bars 6 are burdened.

  Here, in FIG. 13, for the convenience of explanation, the reinforcing reinforcing bars 6 other than the reinforcing reinforcing bars 6 positioned on the left and right outer sides of the conventional pile head joint structure 2 are omitted.

  A bending moment M1 in FIG. 13 represents a bending moment that acts to resist the bending moment M. The bending moment M1 includes the tensile force T generated in the reinforcing reinforcing bar 6 on the right side in the drawing when the bending moment M is applied, and the foundation concrete 8 in contact with the upper end surface 4c of the steel pipe pile 4 on the upper end surface 4c of the steel pipe pile 4. It was generated by the compressive force C pushing the left part in the figure from above.

JP 2006-029040 A

  In recent years, the support capacity and strength of foundation piles such as steel pipe piles 4 have rapidly increased, and the number of steel pipe piles 4 required for supporting one pillar can be reduced, and one pillar can be reduced to 1 Supporting by the steel pipe pile 4 is also performed. Moreover, the outer diameter dimension of the steel pipe pile 4 can also be made smaller than before.

  However, when the number of steel pipe piles 4 is reduced, there is a problem that the horizontal force such as an earthquake borne by one steel pipe pile 4 is increased.

  As a countermeasure against an increase in the horizontal force borne by the steel pipe pile 4, it is conceivable to increase the number of reinforcing bars 6 joined to the outer peripheral surface 4b of the pile head 4a of the steel pipe pile 4.

  However, in the conventional pile head joint structure 2, the beam reinforcement of the foundation beam orthogonal to each other, the main reinforcement of the column not shown, etc., in the foundation concrete 8 and above the pile head 4a of the steel pipe pile 4, etc. As the steel pipe pile 4 is reduced in diameter and the number of reinforcing reinforcing bars 6 joined to the steel pipe pile 4 is increased, the main bars of these beam reinforcing bars and columns and the reinforcing reinforcing bars 6 are There is a problem in that they interfere with each other and a situation where a certain number of reinforcing bars 6 cannot be arranged, that is, an overcrowded arrangement occurs.

  Moreover, in the conventional pile head joining structure 2, since the reinforcing bar 6 was joined to the outer peripheral surface 4b of the pile head 4a by welding, the material having poor weldability even if it is high in strength is the material of the reinforcing bar 6. There was also a problem that it could not be used.

  In view of the above problems, the present invention can effectively reinforce the joint between the pile head of the foundation pile and the foundation concrete, and can also use a reinforcing steel bar made of a material with poor weldability. It is an object of the present invention to provide a pile head joint structure that can reduce the number of reinforcing bars and can eliminate overcrowded bars above the pile head.

In order to solve the above problems, the pile head joint structure according to the present invention is:
In the pile head joint structure in which the pile head of the foundation pile is embedded in the foundation concrete and the foundation pile and the foundation concrete are integrally joined via the reinforcing steel bars,
A plurality of joining members to which the lower ends of the reinforcing reinforcing bars are joined;
The plurality of joining members are joined to the outer peripheral surface of the pile head at intervals, and a length in a direction corresponding to a circumferential direction of the pile head is a radial direction of the pile head. It is characterized by being longer than the length in the direction corresponding to.

Moreover, the pile head joint structure by this invention is
The length of the joining member in the direction corresponding to the axial direction of the pile head is longer than the length in the direction corresponding to the radial direction of the pile head.

Moreover, the pile head joint structure by this invention is
The sum of the joining lengths in the circumferential direction of the pile heads of the plurality of joining members and the pile heads is set to a ratio of 50% or more of the circumferential length of the pile heads. It is characterized by.

Moreover, the pile head joint structure by this invention is
The joining member is characterized in that its upper end surface is disposed below the upper end surface of the pile head and joined to the outer peripheral surface of the pile head.

According to such a pile head joint structure of the present invention,
In the pile head joint structure in which the pile head of the foundation pile is embedded in the foundation concrete and the foundation pile and the foundation concrete are integrally joined via the reinforcing steel bars,
A plurality of joining members to which the lower ends of the reinforcing reinforcing bars are joined;
The plurality of joining members are joined to the outer peripheral surface of the pile head at intervals, and a length in a direction corresponding to a circumferential direction of the pile head is a radial direction of the pile head. Is longer than the length in the direction corresponding to
It is possible to effectively reinforce the joint between the pile head of the foundation pile and the foundation concrete, and use a reinforcing bar made of a material with poor weldability, and reduce the number of reinforcing bars, and It is possible to eliminate overcrowded reinforcement above the pile head.

It is a side view of pile head junction structure 40 concerning a 1st embodiment of the present invention in foundation concrete 48. It is AA arrow sectional drawing of the pile head junction structure 40 in FIG. FIGS. 3A and 3B are diagrams illustrating the joining member 42 in FIG. 1, in which FIG. 3A is a top view and FIG. 3B is a side view. It is a partial cross-section enlarged view which expands and shows the joining member 42 vicinity in the pile head joining structure 40 of FIG. It is a side view which abbreviate | omits and shows a part of the joining member 42 and the reinforcing steel bar 46 in the pile head joining structure 40 of FIG. It is a side view of the pile head junction structure 60 which concerns on the 2nd Embodiment of this invention in the foundation concrete 48. FIG. It is a BB line arrow sectional view of pile head junction structure 60 in FIG. It is a side view of the pile head joining structure 70 which concerns on the 3rd Embodiment of this invention in the foundation concrete 48. FIG. It is a top view of the pile head joining structure 70 in FIG. It is the fragmentary sectional enlarged view which expands and shows the joining member 72 vicinity in the pile head joining structure 70 of FIG. It is a side view which shows the conventional pile head joining structure 2. FIG. It is CC sectional view taken on the line of the pile head junction structure 2 in FIG. FIG. 12 is a schematic partial enlarged view showing a part of the pile head joint structure 2 in FIG. 11 in an enlarged manner and omitting a part of the reinforcing steel bars 6.

  Hereinafter, the form for carrying out the pile head junction structure concerning the present invention is explained concretely based on a drawing.

  FIGS. 1 to 5 are views referred to for explaining a pile head joint structure 40 according to the first embodiment of the present invention.

  As shown in FIG. 1, the pile head joint structure 40 according to the present embodiment includes a steel pipe pile 44 (foundation pile) having a pile head 44a, a plurality of joining members 42, a plurality of reinforcing reinforcing bars 46, A substantially rectangular parallelepiped foundation concrete 48 formed by being placed around these and above the foundation ground 3 is provided.

  The steel pipe pile 44 is formed in a cylindrical shape (see FIG. 2) having a shaft hole extending in the vertical direction in FIG. 1, and its lower end is embedded in the foundation ground 3 until it hits the rock. Moreover, the upper end part of the steel pipe pile 44 protrudes upwards from the foundation ground 3, and the upper end part which protruded upwards from the foundation ground 3 of this steel pipe pile 44 becomes the pile head 44a.

  As shown in FIG. 2, the plurality of joining members 42 are arranged along the circumferential direction of the outer peripheral surface 44 b of the pile head portion 44 a and spaced from each other in the same direction. And as shown in FIG. 1, the some joining member 42 is integrally joined to the outer peripheral surface 44b of the pile head part 44a by welding.

  As shown in FIGS. 3A and 3B, the joining member 42 is formed in a comb-like plate shape having an inner arc surface 42 a and an outer arc surface 42 b, and is formed at the lower end portion of the reinforcing reinforcing bar 46. Two through holes 42c through which the male screw portion 46a is loosely inserted are formed at a distance from each other.

  And the length of the joining member 42 in the direction corresponding to the circumferential direction of the pile head 44a is formed longer than the length in the direction corresponding to the radial direction of the pile head 44a. In other words, the arc length of the inner arc surface 42a and the outer arc surface 42b of the joining member 42 is formed longer than the length of a straight line connecting the inner arc surface 42a and the outer arc surface 42b.

  As shown in FIG. 4, the length of the joining member 42 in the direction corresponding to the axial direction of the pile head 44a (vertical direction in the figure) is the radial direction of the pile head 44a (horizontal direction in the figure). ) Is longer than the length in the direction corresponding to.

  And the upper surface 42d of the joining member 42 is arrange | positioned below the height of the upper end surface 44c of the pile head 44a substantially parallel to the upper end surface 44c of the steel pipe pile 44, and below.

  The joining member 42 is disposed with a space between the inner arc surface 42a and the pile head portion 44a so that the inner arc surface 42a faces the outer periphery surface 44b of the pile head portion 44a. By welding the outer peripheral surface 44b at the welded portion W, the outer peripheral surface 44b is integrally joined to the outer peripheral surface 44b of the pile head portion 44a.

  As shown in FIG. 4, in each of the plurality of reinforcing reinforcing bars 46, the male thread portion 46 a formed at the lower end portion in the length direction (vertical direction in the drawing) is loosely inserted into each through hole 42 c of the joining member 42. The nut member 50 is integrally joined to the joining member 42 by screw coupling to the reinforcing reinforcing bars 46 on the upper surface 42d side and the lower surface 42e side of the joining member 42 (screw fastening).

  As shown in FIG. 2, each of the reinforcing reinforcing bars 46 positioned at each other by joining the lower end portions thereof to the joining member 42, around the pile head 44 a of the steel pipe pile 44 in the foundation concrete 48. They are arranged so as to surround each other in the horizontal direction and are spaced radially outward from the outer peripheral surface 44b of the pile head 44a.

  As shown in FIG. 4, ribs 46 b extending in a direction substantially parallel to the length direction and a direction substantially perpendicular to the length direction of the reinforcing reinforcing bars 46 are formed to protrude outward from the outer periphery. With this rib 46b, the reinforcing steel bar 46 can be fixed to the surrounding concrete foundation 48.

  As shown in FIG. 1, the foundation concrete 48 is formed on the foundation ground 3 so that the joining member 42, the pile head portion 44 a of the steel pipe pile 44, and the reinforcing reinforcing bars 46 are embedded therein. And is formed in a substantially rectangular parallelepiped shape having an upper surface at a position higher than the height position of the upper end of the reinforcing reinforcing bar 46.

  Next, the action and effect of the pile head joint structure 40 according to the present embodiment will be described with reference to FIG.

  When the seismic force F and bending moment M as shown in FIG. 5 are applied by an external force such as an earthquake, the pile head joint structure 40 according to the present embodiment has a pile head 44a of the steel pipe pile 44 and a pile head. The load is applied not only to the foundation concrete 48 in contact with the upper end surface 44c of the portion 44a, the reinforcing reinforcing bar 46 and the foundation concrete 48 in contact with the reinforcing reinforcement 46, but also to the joining member 42 and the foundation concrete 48 in contact with the upper surface 42d of the joining member 42 Be able to.

  Here, in FIG. 5, for convenience of explanation, the joining members 42 and the reinforcing reinforcing bars 46 other than the joining members 42 and the reinforcing reinforcing bars 46 located on the left and right outer sides of the pile head joining structure 40 according to the present embodiment are omitted. It shows.

  Further, a bending moment M2 in FIG. 5 represents a bending moment that acts to resist the bending moment M. The bending moment M2 includes the tensile force T generated in the reinforcing reinforcing bar 46 on the right side in the drawing when the bending moment M is applied, and the foundation concrete 48 in contact with the upper end surface 44c of the steel pipe pile 44 on the upper end surface 44c of the steel pipe pile 44. In addition to the compressive force C pushing the left portion in the figure from above, the foundation concrete 48 in contact with the upper surface 42d of the joining member 42 also acts by the compressive force C1 pushing the upper surface 42d of the joining member 42 located on the left side in the figure. It is like that.

  In such a pile head joint structure 40, the bending moment M2 acting so as to resist the bending moment M can be made larger than the bending moment M1 acting in the conventional pile head joint structure 2. Therefore, the number of reinforcing reinforcing bars 46 joined to the joining member 42 can be reduced accordingly. As a result, it is possible to eliminate overcrowded reinforcement above the pile head 44a.

  Further, in the pile head joint structure 40 according to the present embodiment, by increasing the surface area of the upper surface 42d of the joining member 42, the compression force C1 can be more effectively applied by that amount, and The joint portion between the pile head 44a of the foundation pile 44 and the foundation concrete 48 can be reinforced more effectively.

  However, in order to increase the surface area of the upper surface 42d of the joining member 42, if the length dimension in the radial direction of the pile head 44a in the joining member 42 is too large, the space near the outer peripheral surface 44b of the pile head 44a is effective. Cannot be used, and there is a risk of hindering the joining operation of the pile head 44a of the steel pipe pile 44 and the foundation concrete 48.

  For this reason, in order to increase the surface area of the upper surface 42d of the joining member, it is desirable to increase the circumferential length of the pile head 44a in the joining member 42. Specifically, the sum of the joining length dimensions in the circumferential direction of the pile head 44a of the plurality of joining members 42 and the pile head 44a is the circumferential length dimension of the outer peripheral surface 44b of the pile head 44a. It is desirable that the ratio is set to 50% or more.

  In the pile head joint structure 40 according to the present embodiment, the length of the joining member 42 in the direction corresponding to the circumferential direction of the pile head 44a corresponds to the radial direction of the pile head 44a. Since it is formed longer than the length of the direction, compared with the case where it is formed shorter than the length of the direction corresponding to the radial direction of the pile head part 44a, the joining member 42 and the pile head part 44a are compressed by the compressive force C1. Since the moment applied to the welded portion can be reduced, the welding amount of the welded portion can be reduced.

  Further, in the pile head joint structure 40 according to the present embodiment, the inner arc surface 42a of the joining member 42 and the outer peripheral surface 44b of the pile head portion 44a are arranged with a space therebetween, and they are joined by welding. Therefore, compared with fillet welding in which each of the upper surface 42d and the lower surface 42e of the joining member 42 and the outer peripheral surface 44b of the pile head portion 44a are joined by welding, the welding operation is difficult from the lower surface 42e side. Therefore, the welding operation can be easily performed.

  In the pile head joint structure 40 according to the present embodiment, the length of the joining member 42 in the direction corresponding to the axial direction of the pile head 44a corresponds to the radial direction of the pile head 44a. Therefore, the inner arc surface 42a of the joining member 42 and the pile head 44a are compared with the case where the length is shorter than the length in the direction corresponding to the radial direction of the pile head 44a. The effective cross-sectional area when the outer peripheral surface 44b is welded can be increased, and the joining strength between the joining member 42 and the pile head 44a can be improved.

  For this reason, the stress transmission between the pile head 44a of the steel pipe pile 44 and the reinforcing reinforcing bar 46 through the joining member 42 can be made smooth, and the tensile force T can be effectively applied. The joint part of the pile head 44a of the pile 44 and the foundation concrete 48 can be effectively reinforced.

  Further, in the pile head joint structure 40 according to the present embodiment, the upper surface 42d of the joining member 42 is disposed below the upper end surface 44c of the pile head 44a, so that it is horizontal with the upper end surface 44c of the pile head 44a. Or compared with the case where it arrange | positions upwards from the upper end surface 44c of the pile head part 44a, the said compression force C1 acts effectively with respect to the bending moment M which acts on the pile head part 44a counterclockwise in FIG. Can be made.

  Further, in the pile head joint structure 40 according to the present embodiment, the reinforcing reinforcing bar 46 whose lower end is joined to the joining member 42 is disposed away from the outer peripheral surface 44b of the pile head 44a in the radially outer side. Therefore, it is possible to eliminate overcrowded reinforcement above the pile head 44a.

  Moreover, since the lower end part of the reinforcing steel bar 46 in the pile head joint structure 40 according to the present embodiment is joined to the joining member 42 by screw fastening, the weldability is poor even if the strength is high. The material can be used as the material of the reinforcing steel bar 46.

  Therefore, as explained above, according to the pile head joint structure 40 according to the present embodiment, the joint between the pile head 44a of the foundation pile 44 and the foundation concrete 48 can be effectively reinforced, and Reinforcing bars 46 made of a material with poor weldability can be used, the number of reinforcing bars 46 can be reduced, and over-restricted reinforcement above the pile head 44a can be eliminated.

  Moreover, since the joining member 42 in the pile head joining structure 40 according to the present embodiment is configured to join the two reinforcing reinforcing bars 46, it is possible to reduce the number of welding locations together with the number of joining members 42. Workability can be improved.

  FIG.6 and FIG.7 is a figure referred in order to demonstrate the pile head junction structure 60 which concerns on the 2nd Embodiment of this invention.

  As shown in FIG. 6, the pile head joint structure 60 according to the present embodiment includes a joint member 62 and a reinforcing steel bar 64 instead of the joint member 42 and the reinforcing steel bar 46 in the first embodiment. In the point which has become, it differs from the pile head junction structure 40 which concerns on the said 1st Embodiment.

  As shown in FIG. 7, the joining member 62 is formed in the shape of a dogleg (substantially hexagonal) plate having two inner side surfaces 62a and two outer side surfaces 62b. This is different from the joining member 42 in the embodiment.

  As shown in FIG. 6, the reinforcing reinforcing bar 64 is different from the reinforcing reinforcing bar 46 in the first embodiment in that a male screw part 64 a is formed at the upper end in the length direction. In the reinforcing steel bar 64, the female threaded portion of each of the two nut members 66 (expanded diameter portion) is screwed to the male threaded portion 64a, and the two nut members 66 are coupled to the upper end portion thereof.

  The same effect as the pile head joint structure 40 according to the first embodiment can also be obtained by such a pile head joint structure 60 according to the present embodiment.

  Moreover, since the two nut members 66 are couple | bonded with the upper end part of the reinforcing bar 64, the pile head junction structure 60 which concerns on this Embodiment improves easily the adhesive force of the reinforcing bar 64 and the foundation concrete 48. FIG. be able to. Further, by sandwiching a fixing plate larger than the nut member 66 between the two nut members 66, the reinforcing reinforcing bars 64 can effectively exert the fixing force.

  FIGS. 8 to 10 are views referred to for explaining a pile head joint structure 70 according to a third embodiment of the present invention.

  As shown in FIG. 8, the pile head joint structure 70 according to the present embodiment includes a joint member 72 and a reinforcing steel bar 74 instead of the joint member 62 and the reinforcing steel bar 64 in the second embodiment. In that point, the pile head joint structure 60 according to the second embodiment is different.

  Here, in FIG. 8, for convenience of explanation, the rib 74b (see FIG. 10) formed so as to protrude outward from the outer peripheral portion of the reinforcing steel bar 74 is omitted.

  As shown in FIG. 9, the plurality of joining members 72 are disposed along the circumferential direction of the outer peripheral surface 44 b of the pile head portion 44 a and spaced from each other in the same direction. And the some joining member 42 is integrally joined to the outer peripheral surface 44b of the pile head 44a by welding.

  As shown in FIG. 10, the joining member 72 includes a horizontal plate portion 72a extending in the horizontal direction (left-right direction in the drawing), a vertical plate portion 72b protruding downward from the right end portion in the drawing of the horizontal plate portion 72a, and a vertical plate. Two side plate portions 72c formed in a triangular shape such that the height from the horizontal plate portion 72a gradually decreases from the lower end portion of the plate portion 72b toward the left end portion of the horizontal plate portion 72a in the figure. It is configured.

  As shown in FIG. 9, the two side plate portions 72 c of the joining member 72 are arranged to face each other with a gap in the horizontal direction, and support the horizontal plate portion 72 a of the joining member 72 from the lower side. .

  The horizontal plate portion 72a of the joining member 72 is formed in a substantially pentagonal plate shape (see FIG. 9), and the male screw portion 74c formed at the lower end portion of the reinforcing reinforcing bar 74 is loosely inserted as shown in FIG. One through hole 72d is formed.

  The length of the joining member 72 in the direction corresponding to the circumferential direction of the pile head 44a is longer than the length in the direction corresponding to the radial direction of the pile head 44a. For this reason, the sum of the lengths of the two sides joined to the pile head 44a of the horizontal plate portion 72a of the joining member 72 is the radial direction of the pile head 44a of the horizontal plate portion 72a of the joining member 72 (left and right in FIG. 10). It is formed longer than the length of (direction).

  As shown in FIG. 10, the joining member 72 has the sum of the lengths of the horizontal plate portion 72a and the vertical plate portion 72b in the direction corresponding to the axial direction (vertical direction in the figure) of the pile head portion 44a. The horizontal flat plate portion 72a is formed longer than the length in the direction corresponding to the radial direction of the pile head portion 44a (the left-right direction in the figure).

  And as for the joining member 72, the upper surface of the horizontal board part 72a is arrange | positioned substantially parallel with respect to the upper end surface 44c of the steel pipe pile 44, and below the height of the upper end surface 44c of the pile head 44a.

  The joining member 72 is arranged with a space between the outer peripheral surface 44b so that the inner side surface (the right side surface in FIG. 10) of the vertical plate portion 72b faces the outer peripheral surface 44b of the pile head portion 44a. By welding the inner side surface and the outer peripheral surface 44b of the pile head portion 44a at the welded portion W, the inner surface is integrally joined to the outer peripheral surface 44b of the pile head portion 44a.

  As shown in FIG. 10, each of the plurality of reinforcing reinforcing bars 74 has a male screw portion 74 c formed at the lower end portion in the length direction (vertical direction in the drawing) formed on the horizontal plate portion 72 a of the joining member 72. Each of the through holes 72d is loosely inserted, and on the lower surface side of the horizontal plate portion 72a, the nut member 50 is screwed to the reinforcing reinforcing bar 74 to be integrally joined to the joining member 72 (screw fastening). .

  As shown in FIG. 9, each of the reinforcing bars 74, which are positioned relative to each other by joining their lower ends to the joining member 72, surrounds the pile head 44 a of the steel pipe pile 44 within the foundation concrete 48. They are arranged so as to surround each other in the horizontal direction and are spaced radially outward from the outer peripheral surface 44b of the pile head 44a.

  As shown in FIGS. 8 and 9, the reinforcing reinforcing bar 74 is formed with a bent end portion 74 a that is bent at the upper end portion thereof outward in the radial direction of the pile head portion 44 a.

  The same effect as the pile head joint structure 40 according to the first embodiment can also be obtained by the pile head joint structure 70 according to the present embodiment.

  Further, the pile head joint structure 70 according to the present embodiment is configured such that the joining member 72 includes a horizontal plate portion 72a, a vertical plate portion 72b, and two side plate portions 72c. Compared with the joining members 42 and 62 in the pile head joining structures 40 and 60 according to the second embodiment, the weight of the joining member 72 can be reduced.

  In addition, since the pile head joining structure 70 according to the present embodiment has the bent end portion 74a formed at the upper end portion of the reinforcing reinforcing bar 74, the adhesion between the reinforcing reinforcing bar 64 and the foundation concrete 48 is easily improved. be able to.

  Note that the present invention is not limited to the above-described embodiment, and various modifications are possible as long as the object of the present invention can be achieved.

  For example, in the pile head joint structure 40 according to the first embodiment, the steel pipe pile 44 is used as the foundation pile. However, as the foundation pile in the present invention, concrete is injected into the steel pipe and centrifugal tightening is performed. SC pile (concrete pile with outer shell steel pipe) manufactured by hardening may be used.

  In the pile head joint structure 40 according to the first embodiment, as shown in FIG. 2, the eight joint members 42 are joined to the outer peripheral surface 44 b of the pile head 44 a, but the pile head It is sufficient that two or more joining members 42 are joined to the outer peripheral surface 44b of the portion 44a. In addition, as for the some joining member 42, it is desirable to arrange | position uniformly along the circumferential direction of the outer peripheral surface 44b of the pile head 44a.

  In the pile head joint structure 40 according to the first embodiment, the joining member 42 is formed in a comb-like plate shape having an inner arc surface 42a and an outer arc surface 42b. However, the shape is limited to this shape. However, like the joining member 62 in the second embodiment, it may be formed in a polygonal plate shape having a plurality of sides. Further, the joining member may not be limited to a plate-like outer shape like the joining member 72 in the third embodiment.

  Moreover, although the joining member 42 was arrange | positioned at intervals between the outer peripheral surface 44b so that the inner side arc surface 42a might oppose the outer peripheral surface 44b of the pile head 44a, If the space | interval for welding each other end surfaces is formed, a part of joining member may come to contact a part of pile head.

  In addition, the gap formed between the joining member 42 and the outer peripheral surface 44b of the pile head portion 44a is welded to the outer peripheral surface 44b of the joining member 42 and the pile head portion 44a, so that a part or all of the gap is formed. When buried, the circumferential length of the outer peripheral surface 44b of the pile head 44a in the portion to be buried is defined as the circumferential direction of the pile head 44a of the plurality of joining members 42 and the pile head 44a. It may be included in the total of the joining length dimensions.

  In the pile head joint structure 40 according to the first embodiment, each of the plurality of reinforcing reinforcing bars 46 has a male screw portion 46a at the lower end thereof loosely inserted into each of the through holes 42c of the joining member 42. The pair of nut members 50 are integrally joined to the joining member 42 by screwing the reinforcing member 46 to the reinforcing reinforcing bar 46. However, the joining member 42 and the reinforcing reinforcing bar 46 may be screwed together, for example, joining A female thread portion may be provided in the inner peripheral portion of the through hole 42c of the member 42, and the reinforcing reinforcing bar 46 may be directly screw coupled to the joining member 42 using the female thread portion.

  Further, in the pile head joint structure 40 according to the first embodiment, two through holes 42c are formed in one joint member 42, and two reinforcing reinforcing bars 46 are used by using these through holes 42c. However, one or more through holes are formed in one joining member 42, and one or three or more reinforcing reinforcing bars are used by using these through holes. May be joined.

  Further, in the pile head joint structure 40 according to the first embodiment, the inner arc surface 42a of the joining member 42 and the outer peripheral surface 44b of the pile head portion 44a are joined together by welding. The joining member and the pile head may be joined together by another welding method.

  Further, in the pile head joint structure 60 according to the second embodiment, the two nut members 66 are coupled to the upper end portion of the reinforcing reinforcing bar 64, but the number of the nut members 66 may not be two. Moreover, what is necessary is just to be diameter-expanded rather than the reinforcing steel bar 64, and it does not need to be limited to a nut member.

  Moreover, although the upper end part of the reinforcing bar 74 in the pile head joint structure 70 according to the third embodiment is bent outward in the radial direction of the pile head 44a, it is bent in the radial inner side or in another direction. It may be done.

DESCRIPTION OF SYMBOLS 2 Pile head joint structure 3 Foundation ground 4 Steel pipe pile 4a Pile head 4b Outer peripheral surface 4c Upper end surface 6 Reinforcement reinforcement 8 Foundation concrete 40 Pile head joint structure 42 Joining member 42a Inner circular arc surface 42b Outer circular arc surface 42c Through-hole 42d Upper surface 42e Lower surface 44 Steel pipe pile 44a Pile head 44b Outer peripheral surface 44c Upper end surface 46 Reinforcement reinforcing bar 46a Male thread part 46b Rib 48 Foundation concrete 50 Nut member 60 Pile head joint structure 62 Joint member 62a Inner side face 62b Outer side face 64 Reinforcing bar 64a Male thread part 66 Nut member 70 Pile head joint structure 72 Joining member 72a Horizontal flat plate portion 72b Vertical plate portion 72c Side plate portion 72d Through hole 74 Reinforcing bar 74a Bending end portion 74b Rib 74c Male thread portion C, C1 Compressive force F Seismic force M, M1, M2 Bending moment T Tensile force W Welded part

Claims (4)

In the pile head joint structure in which the pile head of the foundation pile is embedded in the foundation concrete and the foundation pile and the foundation concrete are integrally joined via the reinforcing steel bars,
A plurality of joining members to which the lower ends of the reinforcing reinforcing bars are joined;
The plurality of joining members are joined to the outer peripheral surface of the pile head at intervals, and a length in a direction corresponding to a circumferential direction of the pile head is a radial direction of the pile head. A pile head joint structure characterized by being longer than the length in the direction corresponding to. The pile head joint according to claim 1, wherein a length of the joining member in a direction corresponding to an axial direction of the pile head is longer than a length in a direction corresponding to a radial direction of the pile head. Construction. The sum of the joining lengths in the circumferential direction of the pile heads of the plurality of joining members and the pile heads is set to a ratio of 50% or more of the circumferential length of the pile heads. The pile head joint structure according to claim 1 or 2, characterized by the above-mentioned. The pile head joint according to any one of claims 1 to 3, wherein an upper end surface of the joining member is disposed below an upper end surface of the pile head and joined to an outer peripheral surface of the pile head. Construction.

Images