JP5661165B1 - Pile connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel connection structure having an outer diameter equal to the outer diameter of a pile in a connection structure for connecting PC piles or SC piles.
[Solution]
A plurality of notches 3a, b having symmetrical T-shaped cross sections with respect to the contact surfaces of the upper and lower end plates 2a, 2b are opposed to both the upper and lower end plates 2a, 2b of the pile at the same circumferential position of the pile. The end plates 2a and 2b are provided from the outer periphery toward the inner periphery. The upper and lower end plates 2a and 2b of the pile are aligned so that the T-shaped cutouts 3a and 3b form the recessed portion 3 of the working shape, and the substantially identically shaped working shape cross section is formed in the recessed portion 3 of the working shape section. The insertion piece 4 having the shape is inserted from the outer periphery of the pile to connect the upper and lower end plates 2a and 2b.
[Selection] Figure 6

Description

  The present invention relates to a connection structure for prestressed concrete piles or steel pipe composite piles (hereinafter referred to as PC piles or SC piles) used mainly for civil engineering.

  PC piles are equipped with end plates that hang a round-headed PC steel rod at both ends, and this end plate is attached to the mold of the centrifugal forming machine of the pile, and the formwork is applied while applying tension to the PC steel rod. High strength concrete is supplied inside, and after the concrete is hardened, it is demolded and prestressed in the direction of the pile axis.

  The SC pile is a composite pile of steel pipe and concrete in which hollow concrete is cast in a steel pipe having end plates at both ends. The connection part of the PC pile or the SC pile has been a welded joint structure in which the circumferential parts of the end plates of the upper and lower piles are joined and integrated by fillet welding.

Conventional pile welding connections require welding technicians and are not only difficult in terms of securing qualified welding personnel, but welding work at pile construction sites is subject to weather, and welding In addition to the problem that the characteristics such as the strength of the part depend on the skill of the operator and there are cases where the reliability is lacking, there is a problem that the welding work takes a long time and is inefficient.
In order to solve such a problem, the present applicants have disclosed a mechanical pile connection structure that does not require field welding. The connection structure is a semicircular shape in which one annular groove is provided on each end plate of the pile, and an annular protrusion that fits into the annular groove of the upper and lower piles is provided on the inner diameter and the outer diameter is tapered. A cylindrical inner ring divided into multiple parts is externally fitted to the connection part of the pile, an external ring with the same taper on the inner surface of the inner ring is externally fitted, and this outer ring is pressed in the longitudinal direction of the pile. Thus, the inner ring is tightened by the taper to connect the piles (see, for example, Patent Document 1).
Since this mechanical connection structure disclosed in Patent Document 1 has excellent characteristics, it is widely used. However, this connection structure has a problem that the outer diameter is larger than the outer diameter of the pile.
In the foundation pile for civil engineering, the thickness of the protruding portion of the portion that is larger than the outer diameter of the pile is generally limited to 9 mm or 12 mm depending on the pile diameter.

  In steel pipe piles, as a connection structure for connecting upper and lower piles, a connection structure that is a joint that does not require on-site welding and has an outer diameter equal to the outer diameter of the steel pipe pile is disclosed. The connection structure includes a female cylinder and a male cylinder that can be inserted into and removed from each other at the connection ends of the upper and lower steel pipe piles, and engages with the mating surface on the mating side on the mating surface on the distal end side of the male and female cylinders. Arc plate-like protrusions are provided alternately in the circumferential direction, and after inserting the male cylinder into the female cylinder, the upper and lower piles are rotated around the axis, and the arc-like protrusions are engaged with each other, It is a connection structure that connects the upper and lower piles.

  In this connection structure, an indentation structure that engages with a circumferential groove provided in the counterpart cylinder is provided on the end surface on the pile end side of the arc plate-like projection, and the end surface on the anti-pile end side of the arc plate-like projection is mutually connected after the upper and lower piles are connected. It is a steel pipe pile connection structure that is opposed to each other with a slit and has a pile axis orthogonal surface that transmits the vertical force of the upper and lower piles by contact, and a key member that transmits rotational force to the upper and lower piles between male and female cylinders. For example, see Patent Document 2.)

  The connection structure disclosed in Patent Document 2 is excellent in that there is no portion protruding outward from the outer diameter of the steel pipe pile, but the engaging portions of the arc-shaped protrusions that are engaged with each other are long on the outer periphery of the end plate. The structure is a little more than half, and the structure is slightly complicated.

Japanese Patent No. 3271725 Japanese Patent No. 4456427

  The present invention mainly relates to a PC pile or SC pile connection structure for civil engineering, and provides a novel connection structure. That is, the present invention is a connection structure in which PC piles or SC piles for civil engineering are connected to each other, and is a connection structure in which the outer diameter dimension of the connection part is a protruding dimension within an allowable dimension, and the required connection strength is obtained. An object of the present invention is to provide a pile connection structure that can be sufficiently secured. Of course, the structure does not require on-site welding.

In order to achieve the above object, the connection structure of the present invention comprises:
(A) at least one of the upper and lower piles is a prestressed concrete pile having at both ends an end plate spanned the PC steel bars, met within the thickness of the respective end plate of the connecting portions of the upper and lower pile And embedded in the middle part of the circumferential direction of the adjacent part of the PC steel bar engagement part provided on the end plate of the prestressed concrete pile so that the side away from the mating pile in the vertical direction is blocked A large number of cutouts having a cross-sectional shape having side protruding portions or bulging portions are provided facing the same circumferential position of the upper and lower end plates from the outer periphery of the end plate toward the radially inner side of the pile.
(B) Insert an insertion piece having a cross-sectional shape substantially coincident with the combined cross-sectional shape of the notches formed facing each other in the upper and lower end plates into the notch from the outer periphery of the end plate.
It is the connection structure of the pile characterized by being comprised by two elements called.

  The connection structure of the pile in which the notch that is connected to each other is provided in the end plates that contact the upper and lower piles and the insertion piece is inserted into the recess formed by this notch is not known at all. The present invention is based on such a novel technical idea.

  The present invention is not limited in its specific shape, structure, dimensions, etc. as long as it satisfies the structural requirements (A) and (B). The cross-sectional shape of the notch formed in each of the upper and lower end plates is a cross-sectional shape having a side protruding portion or a bulging portion within the end plate thickness. Any shape such as a letter shape, a Y shape, and other similar shapes may be used. Practically, the shape of the notch and the insertion piece is preferably as simple as possible in cross-sectional shape and easy to process, withstands the bending load acting on the pile and transmits the torsional moment acting on the pile. It is sufficient that the size is sufficient.

  As an optimum design considering mechanical characteristics and processing technology, the cross-sectional shape of the notch is T-shaped in the upper and lower end plates, respectively, and a T-shaped cross section provided facing the upper and lower end plates is provided. It is preferable to form a recess having a cross section of a letter-shaped cross section, and the insertion piece has a cross section of the same shape as that of the concave section. The specific shapes and dimensions of the notches and insert pieces of the present invention can be easily designed by those skilled in the art according to the size of the pile, the purpose of use of the pile, the load applied to the pile, and other conditions. I can do it.

  Further, in the present invention, a pin hole and a pin fitted to the pin hole are formed so that the circumferential position of the T-shaped notch formed on the upper and lower end plates can be accurately matched to form the craft-shaped recess. Is preferably provided so as to face the contact surfaces of the upper and lower end plates. As a result, the construction of the structure of the present invention having extremely precise processing accuracy can be easily carried out at the pile driving site.

  In addition, if measures are taken to prevent the inserted piece inserted into the recess from falling off, it is possible to prevent unexpected accidents during pile driving work or at a later date, and to maintain the expected performance. . For example, as means for preventing the insertion piece from falling off, use of an adhesive, means for adding a known structure such as a screw, a key, caulking, or a cotter, and the size of the recess and the insertion portion of the insertion piece are tightened. There can be used means for press-fitting the insertion piece into the recess and tightening it, means for adding an internal split structure, etc., means for covering the outer periphery of the end plate with a thin band or the like, and other known means.

  In this case, the means other than the means for covering the outer periphery of the end plate with a thin band or the like can have a structure having no portion protruding outward from the outer diameter of the pile. When a thin plate band is attached to the outer periphery of the end plate to cover the outer periphery of the end plate, a ring-shaped band of a thin steel plate with a thickness of 6 mm or less is used, and this thin steel plate is fixed with a countersunk screw. It can be satisfied that the dimension of the pile connecting portion protruding outward is within the limits as a civil engineering pile.

  In the present invention, the outer diameter of the connecting portion of the PC pile or SC pile is within the required limit value, and the connecting portion has a structure that has sufficient strength against the bending load of the pile and sufficiently transmits the torsional moment of the pile. In addition, it is easy to connect the upper and lower piles at the site where the piles are laid, making it an ideal connection structure for civil engineering piles.

  According to the present invention, it is a simple structure as a connection structure for a PC pile or SC pile for civil engineering work, does not require on-site welding, is easy to perform on-site construction, and the outer diameter of the connection portion satisfies the required requirements. In particular, we were able to provide an excellent connection structure.

It is a perspective view which shows the state before the connection of the connection structure of the upper and lower piles of the Example of this invention. It is a perspective view which shows the state after the connection of the connection structure of the upper and lower piles of the Example of this invention. It is a top view of the end plate by the side of a lower pile of an example. It is a side view of the end plate by the side of a lower pile of an example. It is a side view which shows the state after the upper-and-lower end board connection of the connection structure of an Example. It is explanatory drawing which shows the process of inserting the insertion piece of an Example into a recessed part. It is a perspective view of the insertion piece removal prevention band of an Example.

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

  FIG. 1 is a perspective view showing a state before connection of a connection structure of upper and lower PC piles according to an embodiment of the present invention. An end plate 2a is attached to the lower end of the upper pile 1a (only the lower end portion of the pile is shown). An end plate 2b is attached to the upper end of the lower pile 1b (only the upper end portion of the pile is shown). In FIG. 1, the lower end part of the upper pile 1a and the upper end part of the lower pile 1b have shown the state which has faced away, and the upper surface of the end plate 2b of the lower pile 1b is visible. An insertion piece 4 to be described later is also shown. In this embodiment, an example in which a thin ring-shaped drop prevention ring 7 is used is shown.

  FIG. 2 shows a state in which the end plate 2a of the upper pile 1a and the end plate 2b of the lower pile 1b are brought into contact with each other from the state shown in FIG. 1 in the pile connection structure of the embodiment of the present invention. The state immediately before inserting the insertion piece 4 in the recessed part 3 which notches 3a and 3b form is shown. The notches 3a and 3b shown in FIG. 1 are formed in a concave shape 3 in the shape of a letter by matching the positions in the circumferential direction. The insertion piece 4 is inserted into the recess 3. The fall prevention ring 7 is fitted on the outer periphery of the lower pile 1b in advance.

FIG. 3 is a plan view of the end plate 2b of the lower pile 1b, and FIG. 4 is a side view thereof. FIG. 5 is a side view of the connecting portion of the upper and lower piles that have been connected. The insertion piece 4 is inserted into the recess 3 formed by the notches 3a and 3b formed in the upper and lower end plates 2a and 2b, and the connection of the upper and lower piles 1a and 1b is completed, and the fall of the insertion piece is prevented on the outer periphery. A ring 7 is externally fitted. (Partially cut out)
As shown in FIGS. 1 and 3, there is an engagement portion 6 of an 8-shaped PC steel rod for fixing the round head portion of the PC steel rod provided in the pile on the upper surface of the end plate 2 b. . The number of engaging portions 6 of the PC steel bar is determined by the scale of the pile and the like, and is provided on the end plate 2b at equal intervals in the circumferential direction. A notch 3b of the present invention is formed from the outer periphery of the end plate 2b toward the inside in the radial direction of the pile cross section at the intermediate portion of the portion where the engaging portions 6 of these PC steel bars are adjacent. Therefore, the number of notches 3b is the same as the number of engaging portions 6 of the PC steel bar. Similarly, the end plate 2a of the upper pile 1a is formed with a notch 3a having the same cross section as the engaging portion 6 of the PC steel bar and the notch 3b.

  The cutouts 3a and 3b shown in this embodiment show the most preferred embodiment of the present invention, and are cutouts 3a and 3b having T-shaped cross sections provided on the upper and lower end plates 2a and 2b, respectively. . These notches 3a and 3b are formed radially outward from the outer periphery of the end plates 2a and 2b. The notches 3a and 3b have a shape in which the T-shaped lower ends are opposed to each other on the contact surfaces of the upper and lower end plates 2a and 2b. Then, when the end plates 2a and 2b of the upper and lower piles 1a and 1b are brought into contact with each other and the circumferential positions of the notches 3a and 3b having the respective T-shaped cross sections are accurately matched, the notches 3a and 3b having the T-shaped cross sections are aligned. Are integrally formed on the upper and lower sides to form a concave portion 3 having a cross-sectional shape as shown in FIG.

  In order to accurately contact the upper and lower end plates 2a and 2b in this manner, as shown in FIGS. 1 and 3, a positioning pin hole 5 is provided on the upper surface of the end plate 2b of the lower pile 1b. On the lower surface of the end plate 2a of the upper pile corresponding to the hole 5, there is provided a pin (not shown in the figure) that engages with the pin hole 5 to mutually position the end plates 2a, 2b in the circumferential direction. When this pin and the pin hole 5 are matched and the end plates 2a and 2b are brought into contact with each other, the T-shaped cutouts 3a and 3b provided on the upper and lower end plates 2a and 2b are exactly aligned with each other. The notches 3a and 3b form a concave portion 3 having a cross section with an engineering character.

  An insertion piece 4 having substantially the same cross-sectional shape as the cross-sectional shape of the concave portion 3 is inserted into the concave portion 3 from the outer peripheral direction of the pile. The cross-sectional shape of the recess 3, its size and depth, the size of the insertion piece 4 inserted into the recess 3, and the like are determined by design according to the scale of the pile. The design can be easily performed by those skilled in the art depending on the scale, characteristics, application, conditions of the construction site, and the like.

  FIG. 5: is a side view which shows the state which the connection of the upper pile 1a and the lower pile 1b of an Example was completed. An insertion piece 4 is inserted into a concave portion 3 having a cross section of a letter shape formed on the upper and lower end plates 2a and 2b, and the upper and lower piles are connected. A fall prevention ring 7 covering the outer periphery of these insertion pieces 4 is shown partially cut away. The fall prevention ring 7 is attached to a screw hole 42 provided in the insertion piece 4 using a countersunk screw.

  FIG. 6 shows a process of inserting the insertion piece 4 into the recess 3. An insertion piece 4 having substantially the same cross section as that of the recess 3 is inserted into the recess 3 formed by the notches 3a and 3b provided in the end plates 2a and 2b. Into the recess 3.

  By inserting the insertion piece 4 into the recess 3, the upper and lower end plates 2a, 2b are integrated through the insertion piece 4, and the upper and lower piles 1a, 1b are connected.

  FIG. 7 is a perspective view of the fall prevention ring 7 showing an example of the insertion piece fall prevention means of one embodiment of the present invention. This fall prevention ring 7 is a flat steel having a thickness of 6 mm or less formed into a circular shape, is provided with a countersunk screw hole 71, is fitted to the outer diameter of the pile, and the countersunk screw 72 is screwed into the screw screw 42 of the insertion piece 4. Fix it. As shown in FIG. 2, the fall prevention ring 7 is fitted on the outer periphery of the lower pile 1 b and, after connecting the end plates 2 a and 2 b, is attached so as to cover the outer periphery of the insertion piece 4. Prevents falling off. The dropout prevention means (fall prevention ring 7) shown in FIG. 11 is an example, and various other known means can be used as described above.

DESCRIPTION OF SYMBOLS 1a Upper pile 1b Lower pile 2a, 2b End plate 3 Recess 3a, 3b Notch 4 Insertion piece 5 Positioning pin hole 6 Locking part of PC steel bar 7 Fall prevention ring 41 Arrow 42 Screw screw 71 Countersunk screw hole 72 Countersunk screw

Claims (3)

At least one of the upper and lower piles is a prestressed concrete pile having end plates spanned with PC steel rods at both ends, and is within the wall thickness of each end plate of the connecting portion of the upper and lower piles,・ The side embedded in the middle part of the circumference direction of the part where the engaging parts of the PC steel rods provided on the end plate of the concrete pile are adjacent so that the side away from the mating pile in the vertical direction is blocked A plurality of notches having a cross-sectional shape having a protruding portion or a bulging portion are provided facing the same circumferential position of the upper and lower end plates from the outer periphery of the end plate toward the radially inner side of the pile, and the notches There the insert piece having a cross sectional shape that matches the cross-sectional shape of the recess formed by opposing, Ri Na is inserted from the outer periphery of the end plate in the recess, further
At least a part of the inserted pieces inserted into the notch has a screw hole, and the inserted piece inserted into the notch is wrapped around the entire circumference and screwed into the screw hole. Pile connection structure characterized by having a fall prevention ring .   The pile connection structure according to claim 1, wherein the notch is a notch formed from an outer periphery of the end plate to a depth in the middle of the end plate toward the inside in the radial direction of the pile cross section.   3. The pile connection structure according to claim 1, wherein both the upper and lower piles are prestressed concrete piles.

Images