JP2005139731A - Connection structure of pipe pile head, and method of constructing pipe pile head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection structure of a pipe pile head, which has a stable and high bending bearing force imparted thereto, and contributes to reduction of production costs of an outer steel pipe. <P>SOLUTION: According to the connection structure of the pipe pile head, a concrete-filled pipe pile 1 is driven into the ground, and the outer steel pipe 2 having anchoring reinforcements 4 fixed thereto is arranged on the periphery of the head, followed by placing concrete in a gap between the outer steel pipe 2 and the concrete-filled pipe pile 1, and at least an upper peripheral area of the outer steel pipe 2, to thereby connect the concrete-filled pipe pile 1 and a foundation beam 6 together. In the connection structure, an anchoring member 3 is arranged at a lower edge of the outer steel pipe 2 in a manner protruding inward. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a steel pipe pile head joint structure and a steel pipe pile head construction method, and more particularly, a steel pipe pile head including a concrete-filled steel pipe pile and a footing or a foundation beam. The present invention relates to a joint structure and a construction method of a steel pipe pile head.

  Conventionally, as a joint structure of a pile head that joins a concrete-filled steel pipe pile and a foundation beam, for example, as shown in FIG. 12, the steel bar 12 protrudes above the steel pipe pile 11 in the steel pipe pile 11. A method in which concrete is placed and the pile head is joined to the foundation beam 13 (inner rod method), or as shown in FIG. There is known a method (beard muscle method) in which a fixing bar 14 of a book is fixed by welding, concrete is placed, and a pile head is joined to a foundation beam 13. Japanese Examined Patent Publication No. 3-54736 discloses a method (coupler method) in which a screw rebar for joining is fixed with a coupler (connector with a screw hole) and concrete is placed.

  However, in the inner rod method (saddle reinforcing bar method), since the arrangement space of the reinforcing bars is narrowed, the reinforcing bars are overcrowded and inferior in workability. Moreover, since a reinforcing bar is arrange | positioned inside a steel pipe pile, the cross-sectional efficiency with respect to a bending is bad. On the other hand, the whisker reinforcement method has a problem in workability and welding quality when a reinforcing bar is welded to a steel pipe. In addition, the coupler method has a problem in workability and weldability between the coupler and the steel pipe, as in the case of the beard bar method, and further, the cost increases because it becomes a dedicated coupler.

In addition, as an attempt to reduce the cost of the coupler method, Japanese Patent Application Laid-Open No. 11-247184 uses a small-diameter steel pipe as a socket pipe instead of a coupler, welds the small-diameter steel pipe to a steel pipe pile, It is described that a screw rebar is inserted, a lock nut is hung on both ends of the screw rebar protruding from the small-diameter steel pipe, and the lock nut is fastened to the steel pipe. An anti-loosening grout is injected between the small diameter steel pipe and the screw rebar.
However, this method requires a lock nut of the same length as a conventional coupler to transmit the axial force of the screw rebar, and uses a locking grout, resulting in cost reduction. Don't be. Moreover, the problem of the workability and quality of the welding part of a small diameter steel pipe and a steel pipe pile remains.

In order to solve such a problem, Japanese Patent Laid-Open No. 11-13139 or Japanese Patent Laid-Open No. 2000-297472 discloses a steel pipe disposed outside a steel pipe column (steel pipe pile), and between these column steel pipes and the outer steel pipe. Describes a joining method in which reinforcing bars are installed and the gap is filled with concrete (double pipe method). According to this method, the problem of quality due to the use of a special coupler and welding of the reinforcing bar is solved, and the arrangement diameter of the reinforcing bar can be enlarged to increase the cross-sectional efficiency for bending.
However, in this method, since the restriction near the end of the outer steel pipe is not sufficient, the filled concrete is likely to be broken locally, and the fixing performance of the reinforcing bars may be deteriorated. Moreover, since arrangement | positioning of a reinforcing bar becomes an intermediate part of an outer steel pipe and a steel pipe pile, bending strength is inferior compared with the case where a reinforcing bar is arrange | positioned in an outer steel pipe position.

  JP-A-4-146323 discloses a double pile in which an outer pile is arranged concentrically with a pile on the outside of a PC (prestressed concrete) pile, and a pile head joint structure in which reinforcing bars are welded to the outer pile. Is described. However, this technology is intended to improve the bending strength of the pile. If the pile itself has sufficient strength, and the purpose is only to join the pile head, the outer pipe (outer pile) is too long. This increases costs.

  Furthermore, conventionally, as an improvement of the above-mentioned double pipe method, the pile diameter around the pile head of a concrete pile (ready pile) such as a PHC (high-strength prestressed concrete) pile, Place steel pipes with double-sided ribs, which have almost the same height, and place concrete in the pile head and between the pile and steel pipes with double-sided ribs. It has been proposed that the footing and the pile body be joined together, and that the fixing muscle is fixed to the front end of the outer peripheral surface of the double-sided ribbed steel pipe and embedded in the footing (for example, Patent Document 1).

  According to this technology, when a horizontal force is applied due to rolls at the time of an earthquake, the axial displacement between the pile head and the steel pipe inner peripheral surface and the gap between the steel pipe outer peripheral surface and the footing are reduced. Is prevented by the ribs on both sides of the steel pipe, so that the pile head is firmly joined to the footing, and the pile head of the concrete pile is difficult to come out of the footing. In addition, since the fixing bars fixed to the double-sided ribbed steel pipe are embedded in the footing, the joining between the steel pipe and the footing becomes strong.

Japanese Patent Laid-Open No. 9-195286

  However, since this technique uses a steel pipe with a double-sided rib, there is a problem that the manufacturing cost of the steel pipe increases. In addition, this technology has a problem that the resistance force of the pile against the concrete between the pile and the steel pipe with the double-sided rib is weak because nothing is provided on the concrete pile side when the pulling axial force acts on the pile. There is.

The present invention has been made in view of the above circumstances, and has a steel pipe pile head joint structure and a construction of a steel pipe pile head that have a stable high bending strength and can reduce the production cost of the outer steel pipe. It aims to provide a method.
In addition, the present invention can prevent cracking of the concrete filled in the gap between the outer steel pipe and the steel pipe pile even when a pulling axial force acts on the steel pipe pile, and can smoothly apply to the upper footing or the foundation beam. It is an object of the present invention to provide a steel pipe pile head joint structure capable of transmitting a drawing axial force and a steel pipe pile head construction method.

  In order to solve the above-described problem, the steel pipe pile head joint structure according to claim 1 is configured such that an outer steel pipe to which fixing bars are fixed is disposed around the head of the steel pipe pile placed in the ground. The joint structure of the steel pipe pile head in which concrete is cast around at least the upper end of the gap between the outer steel pipe and the steel pipe pile and the outer steel pipe, and the steel pipe pile and the footing or the foundation beam are joined. And the fixing member which protrudes inside is provided in the lower part of the said outer steel pipe, It is characterized by the above-mentioned.

In the invention described in claim 1, since the fixing member protruding inward is provided at the lower part of the outer steel pipe, the concrete filled in the gap between the outer steel pipe and the steel pipe pile is effectively restrained and reinforced. . Therefore, the length of the outer steel pipe can be shortened, and local destruction of the concrete near the lower part of the outer steel pipe can be prevented, and stable and high bending load resistance can be exhibited. Furthermore, since the fixing member is provided at the lower part of the outer steel pipe, it is only necessary to process the lower part of the outer steel pipe, and the manufacturing cost of the outer steel pipe can be reduced. Also, before installation at the factory or on-site, the anchor bars can be fixed to the outer steel pipe in a state where the outer steel pipe is placed horizontally and in good condition, so that the workability and welding quality can be kept good. it can.
As the fixing member, for example, a fixing plate, a fixing wire such as a reinforcing bar, a fixing strip, or the like can be used. A plurality of these may be used, or may be used in combination.

  The steel pipe pile head joint structure according to claim 2 is characterized in that, in the invention according to claim 1, a fixing member is provided on the upper part of the steel pipe pile so as to protrude outward or inward.

  In the second aspect of the present invention, the fixing member provided to the concrete filled in the gap between the outer steel pipe and the steel pipe pile is opposed to the lower part of the outer steel pipe and the upper part of the steel pipe pile against the drawing load. Since the force is applied effectively, it is possible to prevent cracking due to deterioration of the filled concrete even in the situation where the pulling force and bending moment are applied, and smoothly to the upper footing or foundation beam through the outer steel pipe and anchoring bars. The drawing axial force can be transmitted.

  The steel pipe pile head joint structure according to claim 3 is the invention according to claim 1, wherein the inner peripheral surface of the outer steel pipe and one upper portion of the outer peripheral surface portion of the steel pipe pile facing the inner peripheral surface are provided. A fixing member protruding to the other side is provided at the lower part, and a fixing member is provided at a height position between these fixing members on the other side.

  In invention of Claim 3, while the fixing member which protrudes inside is provided in the upper part and lower part of the inner peripheral surface of an outer steel pipe, it is in the height position between the said fixing members of the outer peripheral surface of a steel pipe pile. A fixing member that protrudes outward is provided, or a fixing member that protrudes outward is provided at the upper and lower portions of the outer peripheral surface portion of the steel pipe pile facing the inner peripheral surface of the outer steel pipe. A fixing member protruding inward is provided at a height position between the fixing members on the inner peripheral surface. Therefore, with respect to the pulling-out load, the pulling axial force is smoothly transmitted to the upper footing or the foundation beam between the fixing members at the height positions of the lower part and the intermediate part, as in the second aspect of the invention. be able to. Furthermore, in the present invention, the compressive force can also be effectively applied to the filled concrete between the fixing members provided at the height positions of the upper part and the intermediate part against the indentation load. A reliable load transmission can be performed in a wide area.

  The steel pipe pile head joint structure according to claim 4 is the invention according to any one of claims 1 to 3, wherein the fixing bar fixed to the outer steel pipe has an enlarged diameter portion. It is characterized by being.

  In the invention described in claim 4, since the fixing bar embedded in the footing or the foundation beam has the enlarged diameter portion, the bending moment of the steel pipe pile can be more effectively applied to the footing or the foundation via the fixing bar. Can be transmitted to the beam.

  The steel pipe pile head joint structure according to claim 5 is the invention according to any one of claims 1 to 4, wherein an upper end of the outer steel pipe projects upward from an upper end of the steel pipe pile and the footing or It is located in the foundation beam.

  In invention of Claim 5, since the upper end of an outer steel pipe protrudes upwards from the upper end of a steel pipe pile, and is located in a footing or a foundation beam, this protrusion amount is changed and an outer steel pipe, a steel pipe pile, By adjusting the wrap length (overlapping length), rigid joint, semi-rigid joint or pin joint can be selected according to the required performance of the foundation. In addition, by adjusting the wrap length between the outer steel pipe and the steel pipe pile in this way, the outer steel pipe absorbs the construction error of the steel pipe pile head position, and the footing or the foundation beam can be easily constructed at the regular position. Can do.

  A steel pipe pile head joint structure according to a sixth aspect of the present invention is the invention according to any one of the first to fifth aspects, wherein the fixing muscle is in an unbonded state.

  In the invention described in claim 6, generally, the strain distribution of the anchoring reinforcement is localized (concentrated) at the boundary between the steel pipe pile and the footing or the foundation beam. By providing (unbond), it is possible to obtain a smoothed strain distribution and to prevent breakage of the fixing streaks. When a large horizontal force is applied to the pile head, the anchoring bar yields in the unbonded section, the bending moment reaches a peak, and the pile head becomes semi-fixed.

  The joint structure of the steel pipe pile head according to claim 7, wherein an outer steel pipe is disposed around the head of the steel pipe pile placed in the ground, and the outer steel pipe and the steel pipe pile are separated from each other and the outer A steel pipe pile head joint structure in which concrete is cast around at least an upper end portion of a steel pipe, and the steel pipe pile and a footing or a foundation beam are joined to the outer steel pipe, the footing or the foundation The main bar of the beam is fixed, and a fixing member protruding inward is provided at the lower part of the outer steel pipe.

In the invention according to claim 7, since the fixing member protruding inward is provided at the lower part of the outer steel pipe, the concrete filled in the gap between the outer steel pipe and the steel pipe pile is effectively restrained and reinforced. . Therefore, the length of the outer steel pipe can be shortened, and local destruction of the concrete near the lower part of the outer steel pipe can be prevented, and stable and high bending load resistance can be exhibited. Furthermore, since the fixing member is provided at the lower part of the outer steel pipe, it is only necessary to process the lower part of the outer steel pipe, and the manufacturing cost of the outer steel pipe can be reduced. Moreover, since the main reinforcement of the footing or the foundation beam is fixed to the outer steel pipe, this main reinforcement can exert the same effect as the fixing reinforcement. In addition to this main bar, a fixing bar may be fixed to the outer steel pipe.
As the fixing member, for example, a fixing plate, a fixing wire such as a reinforcing bar, a fixing strip, or the like can be used. A plurality of these may be used, or may be used in combination.

  The joint structure of the steel pipe pile head according to claim 8 is the invention according to claim 7, wherein the footing or the main reinforcement of the foundation beam penetrates the outer steel pipe and is fixed to the outer steel pipe. It is characterized by.

In the invention described in claim 8, since the main reinforcement penetrates the outer steel pipe and is fixed to the outer steel pipe, the effect of the main reinforcement as the fixing reinforcement of the outer steel pipe is enhanced.
As the main reinforcement, for example, a footing or a lower reinforcement of a foundation beam can be used.

  The joining structure of the steel pipe pile head according to claim 9 is the invention according to claim 8, wherein the outer steel pipe is a square steel pipe.

  In the invention described in claim 9, since a square steel pipe is used as the outer steel pipe, it is easy to avoid interference between the reinforcing bar of the pile head and the footing or the reinforcing bar of the foundation beam.

  The steel pipe pile head joint structure according to claim 10 is the invention according to any one of claims 7 to 9, wherein a fixing member that protrudes outward or inward and outward is provided on an upper portion of the steel pipe pile. It is characterized by being.

  In a tenth aspect of the present invention, the fixing member provided opposite to the lower part of the outer steel pipe and the upper part of the steel pipe pile is compressed in the concrete filled in the gap between the outer steel pipe and the steel pipe pile against the drawing load. Since the force is applied effectively, it is possible to prevent cracking due to deterioration of the filled concrete even in the situation where the pulling force and bending moment are applied, and smoothly to the upper footing or foundation beam through the outer steel pipe and anchoring bars. The drawing axial force can be transmitted.

  The construction method of the steel pipe pile head according to claim 11 is provided with a concrete-filled steel pipe pile in the ground, then excavating around the head of the concrete-filled steel pipe pile, and then the outer peripheral surface of the concrete-filled steel pipe pile And an outer steel pipe having a fixing member fixed to the lower portion thereof and a fixing member protruding inward at the lower portion is disposed around the head of the concrete-filled steel pipe pile, and then the head of the concrete-filled steel pipe pile is disposed. The periphery of the portion is backfilled, and then the concrete is also cast inside the outer steel pipe when the foundation concrete is placed, and the concrete-filled steel pipe pile and the footing or the foundation beam are joined.

  In invention of Claim 11, the joining structure of the steel pipe pile head provided with the effect similar to Claim 1 can be manufactured easily.

  The construction method of the steel pipe pile head according to claim 12, wherein a concrete-filled steel pipe pile is provided in the ground, then the periphery of the head of the concrete-filled steel pipe pile is excavated, and then the outer peripheral surface of the concrete-filled steel pipe pile And an outer steel pipe provided with a fixing member protruding inward at the lower part is arranged around the head of the concrete-filled steel pipe pile, and then the back of the head of the concrete-filled steel pipe pile is backfilled At the same time, the main bar of the footing or foundation beam is fixed to the outer steel pipe, and then the concrete is also placed inside the outer steel pipe at the time of foundation concrete placement, and the concrete-filled steel pipe pile and the footing or foundation beam are joined. It is characterized by.

  In invention of Claim 12, the joining structure of the steel pipe pile head provided with the effect similar to Claim 7 can be manufactured easily.

  The construction method of the steel pipe pile head according to claim 13 is provided with a concrete filled steel pipe pile in the ground, then excavating the periphery of the head of the concrete filled steel pipe pile, and then the outer peripheral surface of the concrete filled steel pipe pile The outer steel pipe provided with a fixing member protruding inward at the lower part around the head of the concrete-filled steel pipe pile is so arranged that its upper end protrudes above the upper end of the concrete-filled steel pipe pile. And then backfilling the periphery of the head of the concrete-filled steel pipe pile and fixing the main reinforcement of the footing or foundation beam through the outer steel pipe and then fixing the outer steel pipe to the outer steel pipe. Concrete is also cast inside, and the concrete-filled steel pipe pile and the footing or the foundation beam are joined.

  In invention of Claim 13, the joining structure of the steel pipe pile head provided with the effect similar to Claim 8 can be manufactured easily.

  The construction method of the steel pipe pile head according to claim 14 is the invention according to any one of claims 11 to 13, wherein a fixing member protruding outward or inward / outward is formed on an upper portion of the concrete-filled steel pipe pile. It is provided.

  In invention of Claim 14, the joining structure of the steel pipe pile head provided with the effect similar to Claim 2 or Claim 10 can be manufactured easily.

As described above, according to the present invention, a steel pipe pile head joint structure and a steel pipe pile head joint structure that have a stable high bending strength and can reduce the manufacturing cost of the outer steel pipe can be easily obtained. The construction method of the steel pipe pile head which can be manufactured can be provided.
Further, according to the present invention, it is possible to prevent cracking of the concrete filled in the gap between the outer steel pipe and the steel pipe pile even when a pulling axial force acts on the steel pipe pile, and to prevent the upper footing or foundation beam from being It is possible to provide a steel pipe pile head joint structure capable of smoothly transmitting a drawing axial force and a steel pipe pile head construction method capable of easily producing the steel pipe pile head joint structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and the description thereof is omitted or simplified.
FIG. 1 is a view showing a joint structure of steel pipe pile heads according to a first embodiment of the present invention, where (a) is a longitudinal sectional view, and (b) is a line AA in (a). It is sectional drawing of the pile part which follows.

In this steel pipe pile head joint structure, the head of the concrete-filled steel pipe pile (steel pipe pile) and the foundation beam are joined.
That is, a circular outer steel pipe 2 is arranged around the head of a concrete-filled steel pipe pile (steel pipe pile) 1 placed in the ground so that its upper end coincides with the upper end of the concrete-filled steel pipe pile 1. An annular fixing plate (fixing member) 3 is fixed to the lower end of the outer steel pipe 2 by welding or a fixing tool such as a bolt so as to protrude inward in the radial direction. A gap between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 is filled with a solidifying material such as concrete or mortar.
Further, a plurality of fixing bars 4 are fixed to the upper end portion of the outer peripheral surface of the outer steel pipe 2 by welding or the like so as to protrude upward, for example, at equal intervals in the circumferential direction. Most of these anchoring bars 4 and the upper end portion of the outer steel pipe 2 are embedded in the foundation beam 6. A beam reinforcing bar 7 is embedded in the foundation beam 6.
In FIG. 1, the fixing bars are fixed to the outer peripheral surface of the outer steel pipe. However, if the fixing bars are fixed to the inner peripheral surface, the lower end portion of the fixing bars is located in the concrete, so that there is an advantage that it is not necessary to worry about rust.

  In this steel pipe pile head joint structure, the moment transmission from the concrete filled steel pipe pile 1 to the outer steel pipe 2 is transmitted through the filling concrete in the gap between the outer steel pipe 2 and the concrete filled steel pipe pile 1. Although it is performed by the bearing pressure from the side surface (outer peripheral surface) of the pile 1 to the side surface (inner peripheral surface) of the outer steel pipe 2 and the frictional force of both side surfaces, the filling concrete is formed by the fixing plate 3 provided at the lower end of the outer steel pipe 2. Restrained and reinforced. As a result, local destruction of the filled concrete near the lower end can be prevented, stable and high bending load resistance can be exhibited, and the length of the outer steel pipe 2 can be reduced to 1-1. The length can be shortened to about 5 times.

  The fixing plate may be fixed to the upper end of the outer steel pipe 2, but the fixing bar 4 of the outer steel pipe 2 embedded and fixed in the foundation beam 6 restrains deformation of the upper end portion of the outer steel pipe 1. If it is within the range, it can be omitted.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the present invention.
In this embodiment, instead of the fixing plate 3 of the first embodiment, a plurality (two in this example) of fixing wires (fixing members) 3A are provided below the inner peripheral surface of the outer steel pipe 2. They are fixed by welding along the circumferential direction at intervals in the vertical direction.
In the joint structure of the steel pipe pile head, the dimension protruding radially inward from the outer steel pipe 2 can be reduced, and by arranging a plurality of the steel pipe pile heads, an effect equivalent to that of the fixing plate 3 of the first embodiment can be obtained. Can play.
Note that a fixing band or the like can be used instead of the fixing wire 3A.

FIG. 3 is a longitudinal sectional view showing a third embodiment of the present invention.
In the present embodiment, in addition to the fixing plate 3 of the first embodiment, a plurality (two in this example) of fixing wires (fixing members) 3A are provided on the outer peripheral surface of the concrete-filled steel pipe pile 1. They are fixed by welding along the circumferential direction at intervals in the vertical direction.
This steel pipe pile head joint structure can not only perform more reliable load transmission, but can also cope with a case where a pulling force acts on the concrete-filled steel pipe pile 1. That is, not only the friction resistance of the double pipe structure part but also the fixing plate 3 at the lower end of the outer steel pipe 2 and the fixing wire rod 3A at the upper part of the concrete-filled steel pipe pile 1 are not filled with the outer steel pipe 2 and the concrete with respect to the pull-out load. Since the compressive force is applied to the filling concrete in the gap with the steel pipe pile 1, even when the pulling force and bending moment are applied, it is possible to prevent cracking with deterioration and the double steel pipe length equivalent to the case where the compressive axial force is applied. With the (outer steel pipe length), stable behavior can be secured at the pile head joint.
Note that a fixing band or the like can be used instead of the fixing wire 3A.

FIG. 4 is a longitudinal sectional view showing a fourth embodiment of the present invention.
In the present embodiment, in addition to the fixing wire 3A of the second embodiment, welding or bolts are provided at the upper end of the concrete-filled steel pipe pile 1 so that the fixing plate 3 protrudes radially inward and outward of the pile steel pipe. It is fixed with a fixture such as.
In this steel pipe pile head joint structure, the same effect as that of the third embodiment can be obtained, and the fixing plate 3 projects over the inside of the pile steel pipe. This restrains the rotation of the fixing plate 3 and makes it difficult to apply an extra secondary stress to the end of the pile.
Note that a fixing band or the like can be used instead of the fixing wire 3A.

FIG. 5 is a longitudinal sectional view showing a fifth embodiment of the present invention.
In the present embodiment, in addition to the fixing wire 3A of the second embodiment, a plurality (two in this example) of fixing wires 3A are also vertically spaced above the inner peripheral surface of the outer steel pipe 2. And fixed by welding along the circumferential direction. Also, on the outer peripheral surface of the concrete-filled steel pipe pile 1, a plurality (two in this example) of fixing wires 3A are vertically arranged at a height position between the upper and lower fixing wires 3A and 3A of the outer steel pipe 2. It is fixed by welding along the circumferential direction at intervals.
In the joint structure of the steel pipe pile head, the fixing members 3A and 3A at the height positions of the lower part of the outer steel pipe 2 and the intermediate part of the steel pipe pile 1 with respect to the pull-out load, as in the third embodiment. In between, it can be made to respond | correspond reliably by making compressive force act effectively on filling concrete. Further, in this structure, to the side surface (outer peripheral surface) of the concrete-filled steel pipe pile 1 and the side surface (inner peripheral surface) of the outer steel pipe 2 described in the first embodiment with respect to the indentation load due to axial force or bending moment. Compressive force acts on the filled concrete between the fixing members 3A and 3A at the height of the upper part of the outer steel pipe 2 and the intermediate part of the steel pipe pile 1, as well as the load transmission due to the bearing pressure of the steel and the frictional force on both sides It is possible to make the load transmission at the pile head joint more reliable.
Note that a fixing band or the like can be used instead of the fixing wire 3A.

FIG. 6 is a longitudinal sectional view showing a sixth embodiment of the present invention.
In the present embodiment, the method of providing the fixing wire 3A of the fifth embodiment is changed. That is, the fixing wires 3A and 3A are provided on the upper and lower portions of the outer peripheral surface portion of the concrete-filled steel pipe pile 1 facing the inner peripheral surface of the outer steel pipe 2, and the concrete-filled steel pipe pile is also provided on the inner peripheral surface of the outer steel pipe 2. The fixing wire 3A is provided at a height position between the upper and lower fixing wires 3A and 3A.
This is an example of fixing the fixing bar 4 to the outer steel pipe 2 after the outer steel pipe 2 is installed on the head of the steel pipe pile 1 depending on the situation at the site.
Also in this steel pipe pile head joint structure, the same effects as those of the fifth embodiment can be obtained.

FIG. 7 is a longitudinal sectional view showing a seventh embodiment of the present invention.
The present embodiment is an example in the case where the fixing bar 4 is fixed to the outer steel pipe 2 after the outer steel pipe 2 is installed on the head of the steel pipe pile 1 according to the field situation.
That is, a fixing bracket such as a coupler or a socket pipe is fixed to the upper end of the outer peripheral surface of the outer steel pipe 2 in advance by welding or the like, and after the outer steel pipe is installed on the ground, the threaded reinforcing bar or the tip is threaded. A reinforcing bar or the like is screwed into the fixing bracket, or is sandwiched between upper and lower nuts.

FIG. 8 is a longitudinal sectional view showing an eighth embodiment of the present invention.
The present embodiment is a corresponding example in the case where the required resistance bending moment is still insufficient with the arrangement of the fixing bars 4 expanded in diameter using the outer steel pipe 2.
In the present embodiment, in addition to the fourth embodiment shown in FIG. 4, the anchoring bars 4A are also arranged inside the pile steel pipe.
In this steel pipe pile head joint structure, depending on the design conditions, the anchor bars 4 become overcrowded at the outer steel pipe position, such as when the steel pipe pile is high in strength or the pile thickness is large. In such a case, it is possible to increase the resistance moment by arranging the fixing reinforcement (skin reinforcement) 4A also inside the pile steel pipe. Moreover, since the fixing plate 3 protrudes also inside the pile steel pipe, the filled concrete inside the pile can be pressed in a compressed state, and sound and stable load transmission can be performed.

FIG. 9 is a longitudinal sectional view showing a ninth embodiment of the present invention.
In the present embodiment, in addition to the third embodiment of FIG. 3, a plurality (two in this example) of fixing wires 3 </ b> A are spaced apart in the vertical direction on the inner peripheral surface of the pile steel pipe. And while being fixed by welding along the circumferential direction, the fixing reinforcement 4A is arrange | positioned inside the pile steel pipe. The filled concrete inside the pile is pressed in a compressed state by a plurality of fixing wires 3A on the inner peripheral surface of the pile steel pipe.
Even in this steel pipe pile head joint structure, the same effects as in the eighth embodiment can be obtained.
Note that a fixing band or the like can be used instead of the fixing wire 3A.

FIG. 10 is a view showing a joint structure of steel pipe pile heads according to the tenth embodiment of the present invention.
In this steel pipe pile head joint structure, the head of the concrete-filled steel pipe pile and the foundation beam are joined.
That is, around the head of the concrete-filled steel pipe pile 1 placed in the ground G, a circular outer steel pipe 2 is arranged with its upper end protruding upward from the upper end of the concrete-filled steel pipe pile 1.
The lap length at which the outer steel pipe 2 and the concrete-filled steel pipe pile 1 overlap is normally set to about 1 to 1.5 times the pile diameter of the concrete-filled steel pipe pile 1. When the wrap length is greater than or equal to the pile diameter, the pile head joint structure is made rigid, and when the wrap length is less than the pile diameter, the pile head joint structure is close to semi-rigid or pin joint The joint structure between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 depends on the lap length between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 and can be determined according to the required performance.
In addition, in the case of a double steel pipe method in which the outer steel pipe 2 and the concrete-filled steel pipe pile 1 are overlapped, the outer steel pipe 2 absorbs the construction error at the head position of the steel pipe pile, and the foundation beam can be easily placed at the normal position. Can be constructed.

  A fixing strip (fixing member) 3B having a rectangular cross section is fixed to the lower part of the inner peripheral surface of the outer steel pipe 2 by welding or a fixing tool such as a bolt along the circumferential direction. The fixing strip 3B is also fixed to the upper part of the outer peripheral surface of the concrete-filled steel pipe pile 1 by welding or a fixing tool such as a bolt along the circumferential direction. The gap between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 is filled with a solidifying material such as high-strength concrete or high-fiber concrete as necessary.

Further, a plurality of fixing bars 4 are fixed to the upper end portion of the outer peripheral surface of the outer steel pipe 2 by welding or the like so as to protrude upward at equal intervals in the circumferential direction. The fixing muscle 4 has an enlarged diameter portion 8 at the upper end portion. The enlarged diameter portion 8 may be formed by upset processing, or another member such as a plate may be attached by welding or the like. Most of these fixing bars 4 and the upper end portion of the outer steel pipe 2 are embedded in the foundation beam 6. The upper end portion of the outer steel pipe 2 can transmit the horizontal force from the upper structure to the concrete-filled steel pipe pile 1 by embedding normally about 10 to 20 cm in the foundation beam 6. A beam reinforcing bar 7 is embedded in the foundation beam 6.
Although the figure shows that the ground G is not backfilled, the ground G below the foundation beam 6 is backfilled.

  In this steel pipe pile head joint structure, since the gap between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 is filled with a solidifying material such as concrete, the shearing force from the superstructure is supported by this filled concrete. The pressure is transmitted to the concrete-filled steel pipe pile 1, and the bending moment of the concrete-filled steel pipe pile 1 is transmitted to the foundation beam 6 by the fixing bars 4 fixed to the outer steel pipe 2. In addition, as for the compression axial force, it has the cross-sectional area of the concrete-filled steel pipe pile 1, while when the tensile axial force acts, the adhesion force of the concrete filled in the gap between the outer steel pipe 2 and the concrete-filled steel pipe pile 1. However, since the fixing strips 3B protruding into the concrete are respectively provided at the lower part of the outer steel pipe 2 and the upper part of the concrete-filled steel pipe pile 1, the concrete is effectively restrained and a large tensile force is applied. It can withstand even when force is applied.

Next, the construction method of the steel pipe pile head part for manufacturing such a joined structure of a steel pipe pile head part is demonstrated, referring FIG.
First, the fixing strip 3B is fixed to the lower part of the inner peripheral surface of the outer steel pipe 2 in advance in the factory or at the site by welding or a fixing tool such as a bolt along the circumferential direction, and the upper end portion of the outer peripheral surface. In addition, a plurality of fixing bars 4 are fixed by welding or the like so as to protrude upward at equal intervals in the circumferential direction. It is preferable to use a fixing muscle 4 having a diameter-expanded portion 8.

Next, a pile steel pipe is embedded in the ground G, and pile concrete is driven into the pile steel pipe by a tremy pipe, and the concrete-filled steel pipe pile 1 is formed in the ground G. On the upper part of the outer peripheral surface of the pile steel pipe, the fixing strip 3B is fixed in advance along the circumferential direction with a fixture such as welding or a bolt.
Next, at the time of foundation work, excavate to the pile head and scrape off the pre-prepared concrete of the pile head.
Next, the ground G around the head of the concrete-filled steel pipe pile 1 is excavated.
Next, the outer peripheral surface of the concrete-filled steel pipe pile 1 is washed.
Next, the outer steel pipe 2 including the fixing strip 3 </ b> B and the fixing reinforcement 4 is disposed around the head of the concrete-filled steel pipe pile 1. At this time, the upper end of the outer steel pipe 2 is located above the upper end of the concrete-filled steel pipe pile 1 and the surface of the ground G. In addition, after arrange | positioning the outer steel pipe 2, you may make it wash | clean the outer peripheral surface of the concrete filling steel pipe pile 1. FIG.

Next, the gap between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 is filled with a solidifying material such as concrete or grout.
Next, the ground G around the head of the concrete-filled steel pipe pile 1 is backfilled to the position of the lower end of the foundation beam 6.
Next, at the time of foundation concrete placement, concrete is also placed inside the outer steel pipe 2, and the concrete-filled steel pipe pile 1 and the foundation beam 6 are joined.

  When the concrete is placed inside the outer steel pipe 2 at the time of foundation concrete placement by omitting the step of filling the gap between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 with a solidifying material such as concrete or grout. The gap between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 may also be filled with concrete.

FIG. 11: is a figure which shows the joining structure of the steel pipe pile head concerning the 11th Embodiment of this invention, Comprising: (a) is a longitudinal cross-sectional view, (b) is a BB line of (a). It is sectional drawing which follows.
The present embodiment is an example in which the main bar of the foundation beam 6 is fixed to the outer steel pipe 2 instead of the fixing bar 4 of the tenth embodiment of FIG.
In the present embodiment, a rectangular outer steel pipe 2A is arranged around the head of the concrete-filled steel pipe pile 1 cast in the ground G with its upper end protruding upward from the upper end of the concrete-filled steel pipe pile 1. ing.

  A fixing strip 3B is fixed to the lower portion of the inner peripheral surface of the outer steel pipe 2A along the circumferential direction with a fixture such as welding or a bolt. The fixing strip 3B is also fixed to the upper part of the outer peripheral surface of the concrete-filled steel pipe pile 1 by welding or a fixing tool such as a bolt along the circumferential direction. The gap between the outer steel pipe 2A and the concrete-filled steel pipe pile 1 is filled with a solidifying material such as concrete.

Further, a through hole is formed in a portion of the outer steel pipe 2A protruding above the concrete-filled steel pipe pile 1, and the lower bar (main bar) 7A of the foundation beam 6 passes through the outer steel pipe 2A through the through hole. And is fixed to the outer steel pipe 2A by a nut 9. In this case, screw rebars are used for the lower bars 7A.
The lower reinforcement 7A may be fixed to the outer steel pipe 2A by welding or the like. Further, a reinforcing bar may be fixed in advance to the inner portion of the outer steel pipe 2A, and the lower bar 7A may be fixed to the outer peripheral portion of the outer steel pipe 2A. Further, when the lower reinforcement 7A is welded to the outer steel pipe 2A, a welding receiving plate may be provided on the outer steel pipe 2A in order to facilitate welding. Furthermore, the main bars such as the lower bars 7A of the foundation beam 6 may be fixed to the outer steel pipe 2A by welding, fixtures or the like without providing reinforcing bars inside the outer steel pipe 2A.

The upper part of the outer steel pipe 2 is embedded in the foundation beam 6. The upper part of the outer steel pipe 2 is normally set to about 1 to 1.5 times the pile diameter of the concrete-filled steel pipe pile 1. The horizontal force from the superstructure can be transmitted to the concrete-filled steel pipe pile 1 by normally embedding about 10 to 20 cm in the foundation beam 6.
In addition, although Fig.11 (a) is shown in the state where the ground G is not backfilled, the ground G below the foundation beam 6 is backfilled.

Next, the construction method of the steel pipe pile head for manufacturing such a joint structure of the steel pipe pile head is demonstrated, referring FIG.
First, in the factory or on site, the fixing strip 3B is fixed to the lower part of the inner peripheral surface of the outer steel pipe 2A along the circumferential direction by welding or a fixing tool such as a bolt, and the concrete of the outer steel pipe 2A. A through hole through which the lower bar 7 </ b> A of the foundation beam 6 is inserted is formed in a portion protruding above the filled steel pipe pile 1.

Next, a pile steel pipe is embedded in the ground G, and pile concrete is driven into the pile steel pipe by a tremy pipe, and the concrete-filled steel pipe pile 1 is formed in the ground G. On the upper part of the outer peripheral surface of the pile steel pipe, the fixing strip 3B is fixed in advance along the circumferential direction with a fixture such as welding or a bolt.
Next, at the time of foundation work, excavate to the pile head and scrape off the pre-prepared concrete of the pile head.
Next, the ground G around the head of the concrete-filled steel pipe pile 1 is excavated.
Next, the outer peripheral surface of the concrete-filled steel pipe pile 1 is washed.
Next, the outer steel pipe 2 </ b> A having the fixing strip 3 </ b> B and the through hole is disposed around the head of the concrete-filled steel pipe pile 1. At this time, the upper end of the outer steel pipe 2A is located above the upper end of the concrete-filled steel pipe pile 1 and the surface of the ground G. In addition, you may make it wash | clean the outer peripheral surface of the concrete filling steel pipe pile 1 after arrange | positioning 2 A of outer steel pipes.

Next, the gap between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 is filled with a solidifying material such as concrete or grout.
Next, the ground G around the head of the concrete-filled steel pipe pile 1 is backfilled to the position of the lower end of the foundation beam 6.
Next, the lower bar 7A is fixed to the outer steel pipe 2A with a nut 9 after the lower bar 7A of the foundation beam 6 is inserted through the through hole of the outer steel pipe 2A. In addition, after fixing the lower reinforcement 7A to the outer steel pipe 2A, the ground G may be backfilled.
Next, at the time of foundation concrete placement, concrete is also placed inside the outer steel pipe 2 </ b> A, and the concrete-filled steel pipe pile 1 and the foundation beam 6 are joined.

  When the concrete is placed inside the outer steel pipe 2A during the foundation concrete placement by omitting the step of filling the gap between the outer steel pipe 2A and the concrete-filled steel pipe pile 1 with a solidifying material such as concrete or grout. The gap between the outer steel pipe 2 and the concrete-filled steel pipe pile 1 may also be filled with concrete.

In each of the above-described embodiments, the fixing bar 4 is fixed to the outer peripheral side of the outer steel pipes 2 and 2A, but the fixing position of the fixing bar 4 to the outer steel pipes 2 and 2A is not limited to this. For example, it may be provided on the inner peripheral side or further on both sides, and may be selected as appropriate in design. This is the same when a fixture such as a coupler is used. In each of the above-described embodiments, the circular outer steel pipe 2 or the rectangular outer steel pipe 2A is used. However, the present invention is not limited to this, and a polygonal cross-section steel pipe or the like may be used.
In each of the above-described embodiments, the fixing muscle 4 may be in an unbonded state.

  Moreover, although the said each embodiment demonstrated the joining structure of the steel pipe pile head and the construction method of a steel pipe pile head where the concrete filling steel pipe pile 1 and the foundation beam 6 were joined, Instead, it may be a steel pipe pile not filled with concrete, or may be joined to a footing instead of the foundation beam 6.

It is a figure which shows the joining structure of the steel pipe pile head which concerns on the 1st Embodiment of this invention, Comprising: (a) is a longitudinal cross-sectional view, (b) is a pile part which follows the AA line of (a). It is sectional drawing. It is a longitudinal cross-sectional view which shows the joining structure of the steel pipe pile head which concerns on the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the joining structure of the steel pipe pile head which concerns on the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the joining structure of the steel pipe pile head which concerns on the 4th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the joining structure of the steel pipe pile head which concerns on the 5th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the joining structure of the steel pipe pile head which concerns on the 6th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the joining structure of the steel pipe pile head which concerns on the 7th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the joining structure of the steel pipe pile head which concerns on the 8th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the joining structure of the steel pipe pile head which concerns on the 9th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the joining structure of the steel pipe pile head concerning the 10th Embodiment of this invention. It is a figure which shows the joining structure of the steel pipe pile head concerning the 11th Embodiment of this invention, Comprising: (a) is a longitudinal cross-sectional view, (b) is sectional drawing which follows the BB line of (a). is there. It is a longitudinal cross-sectional view which shows the example of the joining structure of the conventional pile head. It is a longitudinal cross-sectional view which shows the other example of the joining structure of the conventional pile head.

Explanation of symbols

1 Concrete filled steel pipe pile (steel pipe pile)
2, 2A Outer steel pipe 3 Fixing plate (fixing member)
3A fixing wire (fixing member)
3B Fixing strip (fixing member)
4, 4A Anchoring muscle 6 Foundation beam 7A Lower muscle (main muscle)
8 Expanded part 9 Nut G Ground

Claims (14)

An outer steel pipe to which anchoring bars are fixed is arranged around the head of the steel pipe pile placed in the ground, and concrete is provided around the gap between the outer steel pipe and the steel pipe pile and at least the upper end of the outer steel pipe. Is a steel pipe pile head joint structure in which the steel pipe pile and the footing or foundation beam are joined,
A steel pipe pile head joining structure, wherein a fixing member protruding inward is provided at a lower portion of the outer steel pipe.   The joining structure of the pile head according to claim 1, wherein a fixing member protruding outward or inward / outward is provided on an upper portion of the steel pipe pile.   Fixing members projecting to the other side are provided on one upper and lower portions of the inner peripheral surface of the outer steel pipe and the outer peripheral surface portion of the steel pipe pile facing the inner peripheral surface, and the other is fixed to these The joining structure of the steel pipe pile head according to claim 1, wherein a fixing member is provided at a height position between the members.   The joining structure of the steel pipe pile head according to any one of claims 1 to 3, wherein the fixing bar fixed to the outer steel pipe has an enlarged diameter portion.   5. The steel pipe pile head according to claim 1, wherein an upper end of the outer steel pipe projects upward from an upper end of the steel pipe pile and is located in the footing or the foundation beam. Bonding structure.   The steel pipe pile head joint structure according to any one of claims 1 to 5, wherein the anchoring bars are in an unbonded state. The outer steel pipe is arranged around the head of the steel pipe pile placed in the ground, and the concrete is placed around the gap between the outer steel pipe and the steel pipe pile and at least the upper end of the outer steel pipe, A steel pipe pile head joint structure in which the steel pipe pile and footing or foundation beam are joined,
The main structure of the footing or the foundation beam is fixed to the outer steel pipe, and a fixing member protruding inward is provided at the lower part of the outer steel pipe, and the steel pipe pile head joint structure .   The joint structure of the steel pipe pile head according to claim 7, wherein the main reinforcement of the footing or the foundation beam penetrates the outer steel pipe and is fixed to the outer steel pipe.   The steel pipe pile head joint structure according to claim 8, wherein the outer steel pipe is a square steel pipe.   10. The pile head joint structure according to claim 7, wherein a fixing member that protrudes outward or inward and outward is provided on an upper portion of the steel pipe pile. A concrete-filled steel pipe pile is installed in the ground,
Then drill around the head of this concrete filled steel pipe pile,
Next, the outer peripheral surface of the concrete-filled steel pipe pile is cleaned, and an outer steel pipe is provided around the head of the concrete-filled steel pipe pile. ,
Then backfill around the head of the concrete filled steel pipe pile,
Next, at the time of foundation concrete placement, concrete is also placed inside the outer steel pipe, and the concrete-filled steel pipe pile and the footing or the foundation beam are joined together. A concrete-filled steel pipe pile is installed in the ground,
Then drill around the head of this concrete filled steel pipe pile,
Next, while cleaning the outer peripheral surface of the concrete-filled steel pipe pile, around the head of the concrete-filled steel pipe pile, arrange an outer steel pipe provided with a fixing member protruding inward at the bottom,
Next, backfill the periphery of the head of the concrete-filled steel pipe pile, and fix the main reinforcement of the footing or foundation beam to the outer steel pipe,
Next, at the time of foundation concrete placement, concrete is also placed inside the outer steel pipe, and the concrete-filled steel pipe pile and the footing or the foundation beam are joined together. A concrete-filled steel pipe pile is installed in the ground,
Then drill around the head of this concrete filled steel pipe pile,
Next, the outer peripheral surface of the concrete-filled steel pipe pile is washed, and an outer steel pipe provided with a fixing member projecting inwardly at the lower part around the head of the concrete-filled steel pipe pile, the upper end of which is the concrete-filled steel pipe Place it so that it protrudes above the top of the pile,
Next, backfill the periphery of the head of the concrete-filled steel pipe pile, and fix the main reinforcement of the footing or foundation beam to the outer steel pipe through the outer steel pipe,
Next, at the time of foundation concrete placement, concrete is also placed inside the outer steel pipe, and the concrete-filled steel pipe pile and the footing or the foundation beam are joined together.   The construction method of the steel pipe pile head according to any one of claims 11 to 13, wherein a fixing member protruding outward or inward and outward is provided on an upper part of the concrete filled steel pipe pile.

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