JP2021127667A - Concrete pile coated with steel pipe - Google Patents

Abstract

To maintain a usual diameter, to bear an applied tensile force, and to prevent buckling of a steel pipe by an applied compressive force, too, for a concrete pile coated with steel pipes.SOLUTION: A concrete pile body 1 is coated with an upper steel pipe 21 and a lower steel pipe 23 which are vertically divided by a cutout portion 26 with a length L1, without adhesion. Also, a plate fixing plate 11 is fitted into an annular recessed portion 5 of the concrete pile body 1, to support an inner face 22 of the upper steel pipe 21 and an inner face 24 of the lower steel pipe 23 (b). An upper pressing protrusion 43 and a lower pressing protrusion 44 of a connection plate 40 are engaged with an engagement portion 28 of the upper steel plate 21 and an engagement portion 29 of the lower steel pipe 23 from an outside, and the connection plate 40 is tightly fixed to the plate fixing plate 11, to make a concrete pile 50 coated with steel pipes (b). A tensile force is borne by the connection plate 40. A compressive force is absorbed by shortening the length L1 of the cutout portion 26, and is received by the concrete pile body 1 with no adhesion.SELECTED DRAWING: Figure 4

Description

The present invention relates to a pile that is buried in a pile hole and used, and is a concrete pile covered with a steel pipe in which a steel pipe is arranged on the outer periphery of the concrete pile, that is, a so-called SC pile.

Conventionally, when a concrete pile is buried in a pile hole to form a foundation pile, a horizontal force may act near the ground and a tensile force may act at the upper end of the foundation pile. In this case, the concrete pile can sufficiently bear the compressive force, but the tensile force is weak. Therefore, the outer circumference of the concrete pile is covered with a steel pipe, and the tensile force is borne by the steel pipe. So-called SC pile) ”was used.

In this case, when a compressive force acts on the "concrete pile covered with a steel pipe (so-called SC pile)", the steel pipe buckles and swells outward, which may adversely affect the load of the compressive force of the concrete pile.

In order to prevent this, for example, a proposal has been made to provide a concrete layer and an outer shell steel pipe on the outside of the steel pipe to cope with buckling (Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-223207

Although the above-mentioned conventional technique can take measures against buckling of the steel pipe, the cross section (diameter) becomes large, the connection with the concrete pile located below becomes complicated at the time of construction, and further, the concrete layer is formed between the outer shell steel pipe and the steel pipe. There is a problem that the manufacturing becomes complicated.

The present invention solves the above-mentioned problems because it is a concrete pile covered with a normal steel pipe, the adhesion between the steel pipe and the concrete pile portion is reduced, and a notch portion is provided in the steel pipe to form a cushioning portion.

That is, in the present invention, steel end plates are provided above and below the concrete pile body, the outer surface is covered with a steel pipe to reduce adhesion over the entire length, and an annular notch is provided at an intermediate height of the steel pipe. The concrete pile is covered with a steel pipe and is provided with a cushioning portion capable of reducing the compressive force acting on the steel pipe and maintaining the tensile force as it is.

Further, another invention is characterized in that steel end plates are provided above and below the concrete pile body, the outer surface is covered with a steel pipe over the entire length, and the concrete pile is covered with a steel pipe as follows. Is.
(1) Adhesion between the inner surface of the steel pipe and the outer surface of the concrete pile body was reduced.
(2) A cushioning portion is formed in the steel pipe, the cushioning portion forms a notch portion having a predetermined width in the circumferential direction, and the notch portion is restricted from widening the interval of the notch portion, and the interval is increased. It was constructed by locking a connecting plate that allows narrowing.

Further, in the above, it is a concrete pile covered with a steel pipe, which is characterized by being formed as follows.
(1) The upper side of the notch is the upper steel pipe, the lower side of the notch is the lower steel pipe, an upper plate locking portion is formed on the outer surface of the lower edge of the upper steel pipe, and the upper edge of the lower steel pipe is formed. A lower plate locking portion was formed in.
(2) An upper pressing protrusion for locking to the upper plate locking portion is formed on the upper end portion on the inner peripheral side of the connecting plate, and on the lower end portion on the inner peripheral side of the connecting plate, on the lower plate locking portion. A locking protrusion was formed.

Further, the concrete pile covered with the steel pipe according to claim 2, wherein the concrete pile is formed as follows.
(1) A plate fixing plate was provided on the inner surface of the steel pipe to close the notch in the vertical direction. t
(2) The connecting plate and the plate fixing plate were connected by a holder so as to maintain the distance between them.

In the present invention, the outer surface of the concrete pile body is covered with a steel pipe to reduce adhesion, and an annular notch is provided at the intermediate height of the steel pipe. Therefore, the tensile force is borne by the steel pipe and the compressive force is attached. Since the notch is provided in the steel pipe with reduced buckling, buckling can be prevented and the compressive force can be borne by the concrete pile body.

In the embodiment of the concrete pile covered with the steel pipe of the present invention, (a) is a plan view, (b) is a sectional view taken along the line AA, (c) is a front view, and (d) to (f) are connecting plates. (D) is a plan view, (e) is a sectional view taken along the line BB, and (f) is a front view. (A) represents an enlarged AA cross-sectional view, and (b) represents an enlarged BB cross-sectional view. A CC sectional view is shown. It is a cross-sectional view taken along the line CC, and is a partially enlarged view of the cushioning portion. (A) shows before attaching the connecting plate, and (b) shows after attaching the connecting plate.

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

1. 1. Concrete pile 50 covered with steel pipe

(1) Steel upper end plates 7 and lower end plates 8 are fixed to the upper and lower end surfaces of a donut-shaped concrete pile body 1 having a hollow portion 2 and a length L0. An annular recess 5 in the circumferential direction is formed in the vicinity of the upper end plate 7 of the concrete pile main body 1. A steel strip-shaped plate fixing plate 11 is fitted into the annular recess 5 so that the outer peripheral surface 12 of the plate fixing plate 11 is substantially flush with the outer peripheral surface 3 of the concrete pile body 1 in the fitted state. Is formed in. Bolt fixtures (nuts) 15 having screw holes 17 are fixed to the outer peripheral surface 12 of the plate fixing plate 11 at predetermined intervals in the circumferential direction, and the screw holes 17 of the bolt fixtures 15 are arranged radially (FIG. 3). , FIG. 4 (a)).

(2) The steel pipe 20 is formed in the vertical direction with substantially the same length L0 as the concrete pile main body 1, and is cut in the vicinity of the upper end (at the same vertical position as the annular recess 5 of the concrete pile main body 1) with the members removed. The notch 26 is formed, and the upper part of the notch 26 is the upper steel pipe 21 and the lower part is the lower steel pipe 23. Let L1 be the length of the cutout portion in the vertical direction (FIG. 4 (a)).
An annular upper plate locking portion 28 is formed in the circumferential direction slightly above the lower end 21b of the upper steel pipe 21. An annular lower plate locking portion 29 having the same shape as the upper plate locking portion 28 is formed slightly below the upper end 23a of the lower steel pipe 23 (FIGS. 3 and 4 (a)).

(3) Steel pipes 20 (upper steel pipe 21 and lower steel pipe 23) are arranged on the outer peripheral surface 3 of the concrete pile main body 1. At this time, the outer peripheral surface 3 of the concrete pile main body 1 and the inner peripheral surface of the steel pipe 20 (the inner peripheral surface 22 of the upper steel pipe 21 and the inner peripheral surface 24 of the lower steel pipe 23) are not adhered to each other, and both sides (outer peripheral surface 3 and inner surface) are not adhered. It is formed so that stress is not transmitted between the peripheral surfaces 22 and 24). In this state, the tip surface 16 in the radial direction of the bolt fixture 15 is in the radial direction from "the tip surface 28a in the radial direction of the upper plate locking portion 28 and the tip surface 29a in the radial direction of the lower plate locking portion 29". It is formed so that it does not protrude (or is located at the same position) (FIGS. 3 and 4 (a)).
In this state, the upper end 21a of the upper steel pipe 21 is welded and fixed to the lower surface of the upper end plate 7, and the lower end 23b of the lower steel pipe 23 is welded and fixed to the upper surface of the lower end plate 8.

(4) In the vertical direction, a plane arc-shaped connecting plate 40 that can close the cutout portion 26, the upper plate locking portion 28, and the lower plate locking portion 29 of the steel pipe 20 from the outer peripheral side is formed. The connecting plate 40 has a planar shape obtained by dividing a circle into three parts, and the three connecting plates 40 and 40 form a circle in a plan view (FIGS. 1 (b) and 2 (a)).
An upper pressing protrusion that can be locked from above to the upper plate locking portion 28 is formed on the inner surface 42 (steel pipe 20 side) of each connecting plate 40 at the upper end in the vertical direction, and a lower plate locking portion is formed at the lower end in the vertical direction. A lower holding protrusion 44 that can be locked from the lower side is formed on 29. Further, through holes 45 and 45 are formed at positions corresponding to the bolt fixtures 15 (screw holes 17) of the plate fixing plate 11 at substantially the center in the vertical direction of each connecting plate 40 (FIG. 2 (b)). ..

(5) The upper pressing protrusion 43 of each connecting plate 40 is locked above the upper plate locking portion 28 of the upper steel pipe 21 of the steel pipe 20, and the lower pressing protrusion 44 of each connecting plate 40 is locked to the lower steel pipe of the steel pipe 20. The connecting plates 40, 40 are attached to the steel pipe 20 by locking to the lower side of the lower plate locking portion 29 of the 23. Subsequently, the bolt 47 is inserted into the through hole 45 of each connecting plate 40 from the outside, the shaft portion of the bolt 47 is screwed and tightly connected to the screw hole 17 of the bolt fixture 15, and the head portion of the bolt 47 is connected to the connecting plate. The upper steel pipe 21 and the lower steel pipe 23 are integrally connected to the outer surface of the 40 by fixing to 41 (FIGS. 3 and 4 (b)). In this state, the length L0 of the cutout portion 26 of the steel pipe 20 is It is maintained (FIG. 4 (b).

(6) As described above, the steel pipe-coated concrete pile (SC pile) 50 of the present invention is configured (FIGS. 1 (a) to 1 (c), FIGS. 2 (a), 3). In the above, the upper end of the outer peripheral surface 12 of the plate fixing plate 11 is not fixed to the inner surface 22 of the upper steel pipe 21, and the lower end of the outer peripheral surface 12 of the plate fixing plate 11 is fixed to the inner surface 22 of the lower steel pipe 23. However, all of them are in a state of being pressed by the bolt 47.
In the above, the diameter of the concrete pile main body 1 and the diameter of the steel pipe 20 (upper steel pipe 21 and lower steel pipe 23) are the diameters that are maintained as they are, which are adopted in the usual design.

2. Manufacture of concrete pile 50 covered with steel pipe

The steel pipe 20 is in a state where the upper steel pipe 21 and the lower steel pipe 23 are sandwiched between the plate fixing plate 11 and the connecting plate 40 and are tightly connected by bolts 47, and above the upper holding projection 43 and the upper steel pipe 21 of the connecting plate 40. The locking with the plate locking portion 28 and the locking between the lower holding projection 44 of the connecting plate 40 and the lower plate locking portion 29 of the lower steel pipe 23 are maintained and handled in the same manner as a normal steel pipe.
That is, with the upper end plate 7 and the lower end plate 8 welded and fixed to the steel pipe 20 in the above state, the steel pipe 20 (all (or a part) of the inner surfaces of the upper steel pipe 21 and the lower steel pipe 23) is eliminated from adhesion to concrete. Apply a material to reduce (generally oil-based solvents) or attach such a sheet. In addition, the inner peripheral surface of the plate fixing plate 11 is also treated to reduce or eliminate the adhesion with concrete. In this state, if the steel pipe 20 is attached to a molding mold provided in a centrifugal molding machine, concrete is put in, centrifugal molding is performed, and a predetermined curing is performed in the same manner as usual, the steel pipe of the present invention can be used. The covered concrete pile 50 can be completed (FIGS. 1 (a) to 1 (c), FIG. 3).
Further, the concrete pile main body 1 and the annular recessed portion 5 are also formed by the plate fixing plate 11 by ordinary centrifugal molding of concrete.

3. 3. Use of concrete pile 50 covered with steel pipe

(1) The concrete pile 50 covered with the steel pipe formed as described above is mainly connected to the upper end of the concrete pile buried in the pile hole in the same manner as the concrete pile covered with the normal steel pipe (so-called SC pile). , Placed near the ground of connecting piles. The burial work can be performed in the same manner as a concrete pile covered with a normal steel pipe (not shown).

(2) When a tensile force acts on the concrete pile 50 covered with the steel pipe, the connecting plate 40 is integrated with the plate fixing plate 11 by the bolt 47, so that the upper holding projection 43 of the connecting plate 40 and the upper steel pipe The locking of the upper plate locking portion 28 of 21 and the locking of the lower pressing protrusion 44 of the connecting plate 40 and the lower plate locking portion 29 of the lower steel pipe 23 are maintained. Therefore, the upper steel pipe 21, the lower steel pipe 23, and the connecting plate 40 act integrally to bear the tensile force. At this time, since the edge between the steel pipe 20 (upper steel pipe 21 and lower steel pipe 23) and the concrete pile main body 1 is cut, even if the steel pipe 20 (upper steel pipe 21 and lower steel pipe 23) is stretched, it affects the concrete pile main body 1. There is no.

(3) Further, when a compressive force acts on the concrete pile 50 covered with the steel pipe, the compressive force is mainly borne by the concrete pile main body 1. Further, since the edges of the steel pipe 20 (upper steel pipe 21 and lower steel pipe 23) and the concrete pile main body 1 are cut, the connecting plate 40 is integrated with the plate fixing plate 11 by bolts 47, so that the connecting plate is further formed. Reference numeral 40 is integrated with the upper steel pipe 21 and the lower steel pipe 23 in the radial direction. However, the entire steel pipe 20 (upper steel pipe 21 and lower steel pipe 23) shrinks due to the acting compressive force, but the notch 26 (distance between the end 21b of the upper steel pipe 21 and the upper end 21a of the lower steel pipe 23) is formed. It can be absorbed by shortening in the vertical direction. That is, the upper holding projection 43 of the connecting plate 40 and the upper plate locking portion 28 of the upper steel pipe 21 are locked, and / or the lower pressing protrusion 44 of the connecting plate 40 and the lower plate locking portion 29 of the lower steel pipe 23. Although the locking of the steel pipe 20 may be released, it is possible to prevent the steel pipe 20 (upper steel pipe 21 and lower steel pipe 23) from buckling.

(4) Further, when the concrete pile 50 covered with the steel pipe is bent, a compressive force acts on one side and a tensile force acts on the other side. Therefore, the concrete pile 50 covered with one steel pipe can be used. Both the case where the above compressive force acts and the case where the tensile force acts will occur.

4. Other embodiments

(1) In the above-described embodiment, the upper plate locking portion and the lower plate locking portion are annular, but an annular (intermittent annular) structure in which a partially deleted portion is formed may also be formed (Fig.). Not shown).

(2) Further, in the above embodiment, the upper end portion of the outer peripheral surface 12 of the plate fixing plate 11 is not fixed to the inner surface 22 of the upper steel pipe 21, and the lower end portion of the outer peripheral surface 12 of the plate fixing plate 11 is the lower steel pipe 23. Although they were not fixed to the inner surface 22 of the steel pipe and were formed in a state of being pressed by the bolts 47, they can be loosely welded and partially welded to hold the position (not shown).

1 Concrete pile body 2 Hollow part of concrete pile body 3 Outer surface of concrete pile body 4 Circular recessed part of concrete pile body 7 Upper end plate 8 Lower end plate 11 Plate fixing plate 12 Outer surface of plate fixing plate 15 Bolt fixture 16 Bolt fixing Tip of tool 17 Screw hole of bolt fixture 20 Steel pipe 21 Upper steel pipe of steel pipe 21a Upper end of upper steel pipe 21b Lower end of upper steel pipe 22 Inner surface of upper steel pipe 23 Lower steel pipe 23a Upper end of lower steel pipe 23 b Lower end of lower steel pipe 24 Inner surface of lower steel pipe 26 Notch of steel pipe 28 Upper plate locking part of upper steel pipe 29 Lower plate locking part of lower steel pipe 40 Connecting plate
41 Outer surface of connecting plate 42 Inner surface of connecting plate 43 Upper pressing protrusion of connecting plate 44 Lower pressing protrusion of connecting plate 45 Through hole of connecting plate 47 Bolt (holder)
50 Steel pipe covering concrete

Claims (4)

Steel end plates are provided above and below the concrete pile body, the outer surface is covered with a steel pipe to reduce adhesion over the entire length, and an annular notch is provided at the intermediate height of the steel pipe to form the steel pipe. A concrete pile covered with a steel pipe, which is characterized by having a cushioning part that can reduce the applied compressive force and maintain the tensile force as it is. A concrete pile covered with steel pipes, characterized in that steel end plates are provided above and below the concrete pile body, the outer surface is covered with steel pipes over the entire length, and the structure is as follows.
(1) Adhesion between the inner surface of the steel pipe and the outer surface of the concrete pile body was reduced.
(2) A cushioning portion is formed in the steel pipe, the cushioning portion forms a notch portion having a predetermined width in the circumferential direction, and the notch portion is restricted from widening the interval of the notch portion, and the interval is increased. It was constructed by locking a connecting plate that allows narrowing. The concrete pile covered with a steel pipe according to claim 2, wherein the concrete pile is formed as follows.
(1) The upper side of the notch is the upper steel pipe, the lower side of the notch is the lower steel pipe, an upper plate locking portion is formed on the outer surface of the lower edge of the upper steel pipe, and the upper edge of the lower steel pipe is formed. A lower plate locking portion was formed in.
(2) An upper pressing protrusion for locking to the upper plate locking portion is formed on the upper end portion on the inner peripheral side of the connecting plate, and on the lower end portion on the inner peripheral side of the connecting plate, on the lower plate locking portion. A locking protrusion was formed. The concrete pile covered with a steel pipe according to claim 2, wherein the concrete pile is formed as follows.
(1) A plate fixing plate was provided on the inner surface of the steel pipe to close the notch in the vertical direction.
(2) The connecting plate and the plate fixing plate were connected by a holder so as to maintain the distance between them.

Images