JP4517228B2 - Steel pipe concrete pile head structure, steel pipe concrete pile head joining method, unit for joining - Google Patents

Description

  This invention uses a steel pipe concrete pile as an off-the-shelf pile, and is used when a pile head of a steel pipe concrete pile buried in the ground is fixed in the concrete of an upper structural frame such as a footing to form an integral structure. Further, the present invention relates to a pile head structure and a “joining unit” used for a pile head joining method.

(1) Generally, it is constructed as a joint structure between a foundation and a ready-made pile by welding the fixed reinforcement of the foundation to a steel pipe formed on the outer periphery of the head of the ready-made pile (Patent Document 1) In this case, ready-made piles tend to have a larger diameter and higher bearing capacity. At the construction site, many fixed rebars (deformed steel bars) are welded to the outer peripheral surface of the pile head, and the foundation slab (footing) It was integrated with the concrete of the superstructure). Therefore, it has been necessary to improve the welding quality and economy from the viewpoints of changes in the working environment and the welding work period.

(2) In addition, weld the end steel plate larger in diameter than the outer shell steel pipe to the pile head of the ready-made pile, bury the ready-made pile, and then plant the deformed stud for joining on the end steel plate. An invention has been proposed (Patent Document 2).

  In this case, the outer diameter of the end steel plate is larger than the outer diameter of the ready-made pile, and the welding position between the foundation stud and the end steel plate is aligned with the wall thickness center of the outer steel tube, and the pulling force It is said that the deformation of the end steel plate can be prevented. However, because the end steel plate has a larger diameter than the normal end steel plate, the formwork, etc. will be different in the manufacture of ready-made piles such as concrete filling, etc. It is necessary and the versatility is difficult in the whole process.

(3) Moreover, the invention which fixed the metal circular-arc plate which attached the anchor reinforcing bar beforehand to the pile head outer periphery of the buried ready-made pile is also proposed (patent document 3).

  In this case, since the arc-shaped plate is fitted into the concave portion of the pile head of the ready-made pile and screwed with the fixing bolt, it is fixed and can be firmly and stably fixed and joined. However, both the ready-made pile and the fixed reinforcing bar side of the foundation are made of special members, so that the versatility is inferior in terms of economy.

(4) Moreover, in the steel pipe pile, the invention which fixes the base plate with a fixed reinforcement to the pile head of a steel pipe pile by groove welding was proposed (patent document 4). In this invention, since the base plate with anchoring reinforcing bars larger than the pile head pile diameter is welded and fixed to the outer peripheral surface of the pile head pile of the steel pipe pile, the tensile force is increased by appropriately increasing the width of the base plate. Even if the fixed reinforcement of the pile head can be reduced, the same proof strength as before is maintained, and the structure is simplified.

  A steel pipe pile joins a steel pipe with nothing on the upper surface of the pile head and a fixed reinforcing bar, and the steel pipe joint bears both a pulling force and a compressive force, and mainly requires a large bending strength. Suitable for fields where the compression force is not so great.

On the other hand, in the ready-made pile made of concrete, the end steel plate is attached to the head, and the end steel plate and the fixed reinforcing steel are joined, and the joint is mainly drawn out as a bending strength. The compressive force is mainly shared by the concrete body, and it is mainly used in the field where the compressive force is large, and the pulling force is considered accordingly. Basically different.
JP-A-11-21915 JP 2002-167777 A JP 2000-355939 A JP 2000-154536 A

The conventional examples described above are summarized as follows.
(1) Pile end steel plate outer diameter> Pile body outer diameter: Handling of piles, transportation, suspension, etc. is more complicated than before. In addition, a complicated method and management different from conventional methods are required.
(2) When reinforcing the steel plate at the pile end by changing the structure of the pile body: It is necessary to add ribs, etc., inside the pile, which is a different structure from the conventional structure, increasing costs and reducing versatility.
(3) Planting anchored reinforcing bars at the pile ends at the site: The number of welding operations at the site is large, and the welding of the anchoring reinforcing bars to the end steel plate requires skill and the environment becomes unstable. Maintenance is also troublesome in terms of quality. The shape and structure of easy on-site welding work has increased costs.
(4) When fixing the support to the pile end steel plate welded to the fixed reinforcing bar in advance with bolting: In the case of bolting, the shape and processing of the pile end steel plate, multiple bolt holes Formation and screwing are required. In the case of welding, it is necessary to set and learn welding conditions between substrates having different shapes and dimensions. Moreover, welding conditions different from the case of ready-made piles are necessary and need to be learned.
There was no joining structure that satisfies these requirements, had a reliable quality, and a stable workability.

Therefore, the present invention is required to solve the following problems.
(1) As long as the shape and structure of ready-made piles are possible, it is desirable from the viewpoint of versatility that they can be manufactured with the same specifications as normal piles and that normal piles can be used as they are. Also, it is desirable not to employ different and complicated construction methods. In addition, even when different ready-made pile structures are employed, it is desirable that the cost of the material can be reduced by the same construction method.
(2) The work conditions such as fixing between the fixed reinforcing bar of the foundation and the steel plate at the end of the pile are stable, the joining work at the construction site is easy, the construction period is stable, reliable quality and economical It is desirable to be excellent.
(3) It is desirable that the pull-out force of the anchoring reinforcement of the foundation can be reliably transmitted to the end steel plate part of the pre-made pile and the pre-made pile main body (embedded deformed rebar or outer shell steel pipe).

  However, in the present invention, the fixing rebar is erected on the annular plate, the joining unit is constructed, and the pile head structure is constructed by joining the pile head of the steel pipe concrete pile. .

That is, this invention joins the annular plate which has an opening inside to the upper surface of the cyclic | annular pile edge part steel plate provided in the pile head part of a steel pipe concrete pile, and on this annular plate, it has several annularly arrange | positioned. A steel pipe in which a fixing rebar is installed and fixed, and a part or all of the inner peripheral edge of the opening forms a welding allowance with the top surface of the pile end steel plate, and is welded at the welding allowance. It is a pile head structure of a concrete pile.

  In the above, the pile of the steel pipe concrete pile, wherein the outer diameter of the annular plate is formed larger than the outer diameter of the pile of the steel pipe concrete, and a plurality of anchoring reinforcing bars are located immediately above the steel pipe of the steel pipe concrete pile It is a head structure. Further, the inner diameter of the annular plate is formed larger than the inner diameter of the annular pile end steel plate, and “the inner peripheral edge of the annular plate and the pile end steel plate” and / or “the annular plate and the pile end steel plate” This is a pile head structure of a steel pipe concrete pile characterized by welding the outer periphery of the steel pipe. Moreover, it is the pile head structure of the steel pipe concrete pile characterized by joining this pile end steel plate and the annular plate with the volt | bolt using the bolt hole previously formed in the pile end steel plate of a steel pipe concrete pile.

Moreover, invention of a method is a pile head joining method of the steel pipe concrete pile characterized by taking the following procedures.
(1) A steel pipe concrete pile with an annular pile end steel plate installed at the pile head is built in the ground,
(2) A joining unit comprising a plurality of fixing reinforcing bars standing and fixed in a ring shape on an annular plate having an opening on the inside is formed in advance.
The annular plate of the joining unit was placed on the upper surface of the pile end steel plate, and formed between a part or all of the inner peripheral edge of the opening of the annular plate and the upper surface of the pile end steel plate. Weld and join at the welding fee ,
(3) Placing concrete around at least the joining unit to form an upper structural frame, and integrally bonding the upper structural frame and the pile head of the steel pipe concrete pile.

Furthermore, another invention is formed by fixing and fixing fixing reinforcing bars arranged in parallel in an annular manner on the upper surface of an annular plate that can be placed on the upper surface of a pile end steel plate of a steel pipe concrete pile. It is formed larger than the outer diameter of the pile end steel plate , the annular plate has an opening on the inside, and the opening can form a welding allowance between a part or all of the inner peripheral edge and the upper surface of the pile end steel plate It is the unit for joining characterized by having such a shape .

  In the above, the bolt hole provided in the pile end part steel plate can be diverted, for example, when the bolt hole used when introducing prestress into the concrete portion of the concrete pile to be used exists.

  Since an annular plate with a fixed reinforcing bar is fixed to the upper surface of the pile end steel plate in advance, it is possible to omit the standing work of the fixed reinforcing bar on the annular plate at the construction site and to shorten and stabilize the construction period. . Moreover, it is not necessary to perform the work of joining the pile end steel plate and the fixing rebar in a narrow place of the pile placement site, and the workability of the construction work of the fixing rebar can be improved.

  It is easy to make the outer diameter of the annular plate larger than the outer diameter of the steel pipe concrete, and it is easy to position the anchoring rebar directly above the steel pipe. In this case, when the horizontal force acts on the pile head, it is slightly displaced. However, since no eccentric stress is generated in the pile, the design of the pile is easy, and there is an effect that it is possible to ensure the yield strength as designed. Furthermore, since a jig for holding adjustment is not required for joining the annular plate and the pile end steel plate, there is an effect that the construction period can be shortened and workability can be improved.

  In addition, when welding the “inner peripheral edge of the annular plate and the pile end steel plate” and / or “outer peripheral edge of the annular plate and the pile end steel plate”, the annular plate and the pile end steel plate are joined together. Strong integration can be easily achieved. Therefore, it is possible to reliably transmit stress from the superstructure to the steel pipe concrete pile.

  Also, by using the bolt holes of the pile end steel plate, for example, by forming a through hole or bolt hole in the annular plate and screwing the common bolt, the annular plate can be easily attached to the pile end steel plate annular plate. Can be joined and workability can be improved.

(1) The annular plate 1 is welded to the fixing reinforcing bar 8 along the circumference of the circle 7 on the annular plate as a donut shape made of a steel plate having a thickness t ₁ , an outer diameter D ₁ , and an inner diameter D _2. Unit (FIG. 1). When the end steel plate of the ready-made pile to which this joining unit is applied is set to thickness t ₀₁ , outer diameter D ₀₁ , inner diameter D ₀₂ ,
D ₀₁ <D ₁ , D ₀₂ <D ₂ , t ₁ ≦ t ₀₁
It forms so that it becomes.
When the annular plate 1 of the joining unit 10 is placed on the pile end steel plate 13 of the ready-made pile 12 and fixed integrally, a pile head structure 18 is configured (FIG. 1).

(2) In this case,
An inner diameter D ₂ of the annular plate 1, if larger than the inner diameter D ₀₂ of the ready-made pile 12, taking the welding margin of the upper surface 14 of Kuitan section steel 13, easily welding work.
Further, the outer diameter D ₁ of the annular plate 1, is made larger than the outer diameter D ₀₁ of the ready-made pile 12, take the welding margin of the lower surface 3 of the annular plate 1, the welding operation is made easy, the fixing reinforcement 8 Since the welding position can be matched at the thickness center position of the steel pipe (outer steel pipe) 16 of the ready-made pile 12, the bending strength and the pulling-out force can be improved.
Further, if smaller than the dimension of the thickness t ₀₁ of the pile end steel plate 13 of the ready-made pile 12 plate thickness t ₁ of the annular plate 1 facilitates welding operations.
Moreover, (the difference between the outer diameter D ₀₁ of the annular plate 1 of the inner diameter D ₂ and Kuitan section steel 13) annular plate 1 and the width of the overlapping portion of the Kuitan section steel 13, at least the timber diameter of the fixing reinforcing bars 8 If it is formed at twice or more, the integrity of the joint between the two can be secured, and the bending strength and the pulling force can be improved.
Further, if the circle 7 in which the fixed reinforcing bar is disposed is made to be an intermediate diameter between the outer diameter D ₁ and the inner diameter D ₂ and matches the center position of the thickness of the steel pipe 16 of the ready-made pile 12 in the annular plate 1, The pulling force can be improved.

(3) It is preferable that the outer diameter D ₁ and the inner diameter D ₂ of the annular plate 1 are the same as the inner and outer diameter dimensions of the end steel plate on one rank of the concrete ready-made pile to be used. That is, there exists an advantage which can use the edge part steel plate for existing piles from which the size differs in the annular plate 1 as it is, without changing a type | mold dimension.
For example, the annular plate 1 used for the ready-made pile with the outer diameter D ₀₁ = 400 mm can adopt the inner and outer diameter dimensions of the end steel plate of the ready-made pile with the outer diameter D ₀₁ = 450 mm. Moreover, the annular plate 1 used for the ready-made pile of outer diameter _D01 = 800mm can employ | adopt the edge part steel plate for ready-made piles of outer diameter 900mm.

Embodiments of the present invention will be described with reference to the drawings.

[1] Configuration of joining unit 10

(1) The annular plate 1 is composed of a donut-shaped steel plate having a thickness t ₁ , an inner diameter D ₂ , and an outer diameter D ₁ . The inside of the annular plate 1 constitutes the opening 5. Along the circular plate 1 having a diameter D ₃ on the annular plate 1 (an inner diameter D ₂ and a concentric circle with the outer diameter D ₁ ), the fixing reinforcing bars 8 and 8 are erected in a ring shape and fixedly welded to the annular plate 1. At this time, four fixing reinforcing bars 8 are arranged at equal intervals on the circumference of the circle 7, and the fixing reinforcing bars 8 a, 8 b, 8 c, and 8 d all have the center (axis) of the fixing reinforcing bar 8 positioned on the circle 7. . (FIGS. 1 and 3).

  The joining unit (joining unit) 10 is configured as described above. The joining unit 10 may be formed by welding and fixing the fixed reinforcing bar 8 to the annular plate 1 in advance or in parallel with the construction work of a ready-made pile at the site. It may be transported to the construction site.

(2) The ready-made pile (steel pipe concrete pile, commonly known as “SC pile”) 12 used in this invention is a steel pipe (outer steel pipe) 16 wound around the outer periphery of a cylindrical concrete 17 and pile end steel plates 13 at the upper and lower ends. , 13 are integrally formed (FIG. 1 (b), FIG. 2 (a)). Moreover, it is formed with the thickness t ₀₁ , the outer diameter D ₀₁ , and the inner diameter D ₀₂ of the pile end steel plate 13, and has the following numerical values, for example.
Outer diameter D ₀₁ of ready-made pile 12 = 800 mm
Inner diameter D ₀₂ = 580 mm
Pile end steel plate 13 thickness t ₀₁ = 28 mm
When the joining unit 10 is applied to this ready-made pile 12,
D ₀₁ <D ₁ , D ₀₂ <D ₂ , t ₁ ≦ t ₀₁
It is as. For example, assume the following numerical values.
Outer diameter D ₁ of the annular plate 1 of the joining unit 10 = 900 mm
Inner diameter D ₂ = 660 mm
Diameter D _{3 of} circle 7 = 786 mm
Thickness t ₁ = 28mm
Incidentally, _{D 3,} the center position in the thickness of the steel pipe 16 (i.e., the diameter _{D 03} of the center of the thickness of the steel pipe 16) are made to coincide (Fig. 1, Fig. 3).

(3) In the above-described embodiment, the fixing reinforcing bar 8 is welded as it is to the upper surface 2 of the annular plate 1, but it is also possible to make a hole in the annular plate 1 and weld it after inserting the fixing reinforcing bar 8 into the hole (see FIG. Not shown).

  Moreover, in the said Example, although the annular plate 1 was formed in the donut shape, the shape is arbitrary (not shown). However, the annular plate 1 needs to be able to form a circle 7 and to be able to arrange the fixing reinforcing bars 8 and 8 at positions along the outer periphery of the ready-made pile 12. Further, the annular plate 1 has an opening 5, and some of the inner peripheral edges 4 of the opening 5 are located on the upper surface 14 of the pile end steel plate 13 of the ready-made pile 12, and the inner peripheral edge 4 of the opening 5 and the pile end It is necessary that a welding allowance can be formed between the upper surface 14 of the partial steel plate 13.

Moreover, in the said Example, since the circle | round | yen 7 was made to correspond with the center diameter _D03 position of the thickness of the steel pipe 16 of the ready-made pile 12 to be used, it can improve a bending strength, but although it is desirable, at least the ready-made pile 12 What is necessary is just to be located in the outer periphery periphery of. Therefore, in this case, when the outer diameter of the ready-made pile 12 to be used is D ₀₁ , the diameter D _{3 of the} circle 7 ≒ the outer diameter D _{01 of the} ready-made pile
It becomes.

[2] Joining of ready-made pile 12 and superstructure 20

(1) The ready-made pile 12 in which the circular pile end steel plate 13 is provided on the pile head is built in the ground by a normal foundation pile construction method (FIG. 2 (a)). The ready-made pile 12 has a pile head exposed to the ground. The ready-made pile 12 is a steel pipe concrete pile (commonly called “SC pile”) as described above, and has an outer diameter D ₀₁ and an inner diameter D ₀₂ and a thickness t ₁ of the pile end steel plate 13.

(2) Subsequently, after cleaning the upper surface 14 of the pile end steel plate 13, the lower surface 3 of the annular plate 1 of the joining unit 10 is placed on the upper surface 14 of the pile end steel plate 13 (FIG. 2 (b)). .

 At this time, the through holes 9 and 9 are drilled in the annular plate 1 in accordance with the position of the outer peripheral edge 15 of the pile end steel plate 13 of the ready-made pile 12 (that is, the position of the outer surface of the steel pipe 16) (FIG. 1 (a )), The pin inserted into the through hole 9 is projected downward. The inner side of the pin and the outer peripheral edge 15 of the pile end steel plate 13 of the ready-made pile 12 are matched. Thereby, the position of the circle 7 in which the fixing reinforcing bars 8 are arranged can be matched with the center position of the thickness of the steel pipe 16 of the ready-made pile 12.

  Subsequently, the inner peripheral edge 4 of the annular plate 1 and the upper surface 14 of the pile end steel plate 13 are welded at the position A by work from above (FIGS. 1B and 3). Further, if necessary, the outer peripheral edge 15 of the pile end steel plate 13 and the lower surface 3 of the annular plate 1 are welded at the B position by a welding operation from below (FIGS. 1B and 3). Thereby, the ready-made pile 12 and the fixing reinforcing bars 8 and 8 are fixed integrally. Moreover, it is desirable to cut off the outer periphery of the upper surface 14 of the pile edge part steel plate 13 of the ready-made pile 12 diagonally, and to form the welding allowance here.

  In this state, the pile head structure 18 is constructed (FIG. 2B, FIG. 1).

(3) Subsequently, a formwork for footing (superstructure) is constructed, a reinforcing bar is placed in the formwork (not shown), and concrete is placed. If the concrete is solidified and a predetermined strength is developed in the concrete, the pile head of the ready-made pile 12 is fixed in the footing 20 together with the fixing reinforcing bar 8, and the ready-made pile 12 and the footing 20 are integrated. (FIG. 2 (c)).

[3] Other embodiments

(1) In the above-described embodiment, the annular plate 1 and the upper end steel plate 10 are fixed by welding. However, since there is a margin in shape and dimension, bolt holes are formed in both the annular plate 1 and the upper end steel plate 10. Alternatively, a bolt hole can be formed on one side and a through hole can be formed on the other side, which can be bolted and fixed together (not shown). In this case, when a bolt hole (for example, for introducing prestress into the concrete portion 17) is formed in the pile end steel plate 13 in advance, it can also be used as this bolt hole (not shown). It is also possible to fix the pile end steel plate 13 and the annular plate 1 using bolts common to the pile end steel plate 13 and the annular plate 1. In this case, it is possible to eliminate or reduce the welding operation at the A part and the B part in the embodiment.

  In particular, when welding of the B part is omitted by using bolt joint or the like, there is an advantage that large-diameter excavation of a pile hole head which is a work space necessary for welding of the B part is not required.

(2) In the above-described embodiment, the fixing reinforcing bars 8a, 8b, 8c and 8d are arranged on the circle 7. However, the fixing reinforcing bars 8 and 8 can be shifted and arranged. For example, the fixing reinforcing bar 8c can be arranged on the inner side and the fixing reinforcing bar 8d can be arranged on the outer side so as to be shifted from the circle 7 (FIG. 4). In this case, if the misalignment is formed to be about one half (radius) of the outer diameter of the fixing reinforcing bar 8, a tensile force is applied to the fixing reinforcing bar 8, for example, the maximum displacement of both is 0. 0 at the maximum load (280 kN). It is confirmed that there is no problem at 3 mm or less.

(3) In the above-described embodiment, the through hole 9 is formed in the annular plate 1 and the position is aligned with the pin. However, other methods may be used (not shown). For example, the through hole 9 is not formed in the annular plate 1, and the inner peripheral position (diameter D ₂ ) of the annular plate 1 is marked on the upper surface 4 of the pile end steel plate 13, or the outer diameter of the pile end steel plate 13 The position (diameter D ₀₁ ) can also be marked on the lower surface 3 of the annular plate 1 (not shown). In addition, it can also align using the bolt hole of the pile edge part steel plate 13 of said (1) (not shown).

In the pile head structure of the present invention, (a) is a plan view and (b) is a longitudinal sectional view. (A)-(c) is the schematic longitudinal cross-sectional view explaining the pile head joining method of this invention. It is an enlarged vertical sectional view explaining the relationship between an annular plate and a steel pipe. In another pile head structure of the present invention, (a) is a plan view and (b) is a longitudinal sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ring plate 2 Ring plate upper surface 3 Ring plate lower surface 4 Ring plate inner periphery 5 Ring plate opening 7 Circle 8, 8a, 8b, 8c, 8d Anchor reinforcement 9 Pin 10 Joining unit 12 Ready-made pile (steel pipe concrete pile )
13 Upper-end steel plate 14 of ready-made pile Upper surface 15 of upper-end steel plate Outer peripheral edge 16 of upper-end steel plate Steel pipe 18 of ready-made pile Pile head structure 20 Footing (upper structural frame)

Claims (6)

An annular plate having an opening on the inner side is joined to the upper surface of an annular pile end steel plate provided at the pile head of a steel pipe concrete pile, and a plurality of anchoring reinforcing bars arranged in an annular shape are erected on the annular plate. Fixed ,
A pile of steel pipe concrete piles, wherein a part or all of the inner peripheral edge of the opening forms a welding allowance with the upper surface of the pile end steel plate and is welded with the welding allowance Head structure. The steel pipe concrete pile according to claim 1, wherein the outer diameter of the annular plate is formed larger than the outer diameter of the steel pipe concrete pile, and a plurality of anchoring reinforcing bars are positioned directly above the steel pipe of the steel pipe concrete pile. Pile head structure. The inner diameter of the annular plate is formed larger than the inner diameter of the annular pile end steel plate, and “the inner edge of the annular plate and the pile end steel plate” and / or “outside of the annular plate and the pile end steel plate” The pile head structure of a steel pipe concrete pile according to claim 1 or 2, wherein the "periphery" is welded. 4. The pile end steel plate and the annular plate are joined with bolts using bolt holes formed in advance in the pile end steel plate of the steel pipe concrete pile. Pile head structure of steel pipe concrete pile. A pile head joining method for steel pipe concrete piles characterized by the following steps.
(1) A steel pipe concrete pile with an annular pile end steel plate installed at the pile head is built in the ground,
(2) A joining unit formed by fixing a plurality of fixing reinforcing bars in a ring shape on an annular plate having an opening on the inside is formed in advance.
The annular plate of the joining unit was placed on the upper surface of the pile end steel plate, and formed between a part or all of the inner peripheral edge of the opening of the annular plate and the upper surface of the pile end steel plate. Weld and join at the welding fee ,
(3) Placing concrete around at least the joining unit to form an upper structural frame,
The superstructure and the pile head of the steel pipe concrete pile are joined together. On the upper surface of the annular plate that can be placed on the upper surface of the steel plate end pile of steel pipe concrete pile,
Forming the outer diameter of the annular plate larger than the outer diameter of the pile end steel plate,
The annular plate has an opening on the inner side, and the opening has a shape capable of forming a welding allowance between a part or all of the inner peripheral edge and the upper surface of the pile end steel plate. A joining unit.

Images