Mechanical joints in steel pipe piles

Abstract

To enable quick and reliable steel pipe connection with good workability while eliminating necessity for any processing such as drilling holes in upper and lower steel pipes.SOLUTION: Locking members 3 having spaced separation parts 3aa that form a space with respect to a pipe external surface are provided at multiple locations spaced apart in a circumferential direction of an outer circumferential surface in the vicinity of a connection part. There are multiple arc-shaped joint plates 4 surrounding the outer periphery of the connection part of upper and lower steel pipes, the joint plates have vertically elongated openings 4a that allow vertical relative movement with respect to the locking members, and are passed through the space of the separation parts of the locking members at the openings and pulled down to engage with the locking members. Restraining pieces 6 that restrain the joint plates from moving downward are fitted into the space below the openings. Covers 7 that hold the restraining pieces are placed on the outside of the joint plates and are fixed to the joint plates with bolts 9.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a mechanical joint for connecting steel pipes in a steel pipe pile, and particularly to a mechanical joint when the outer diameters are the same.

Background Art

[0002] When constructing a steel pipe pile, it is usually necessary to connect steel pipes of the same diameter. The connection of steel pipes of the same diameter is usually carried out by on-site welding. However, since the on-site welding work is complicated, a mechanical connection structure is often used. When adopting a mechanical connection structure, there are a direct connection structure in which the upper and lower steel pipes are directly brought into contact with each other, and a separate member interposed connection structure in which the separated upper and lower steel pipes are connected through a connecting member which is a separate member. As a separate member interposed connection structure, for example, there is JP-A-11-81304 (Connection structure of steel pipes: Patent Document 1). This Patent Document 1 (FIG. 20) will be described using the reference numerals in Patent Document 1. Cylindrical connection parts 1 and 21 having an outer diameter smaller than the diameter of the steel pipe pile are fixed (presumably by welding) to the butting edge parts 10a and 11a of the upper and lower steel pipe piles 10 and 11 to be connected, respectively, and screw holes 3 and 23 are provided on the side surfaces of the upper and lower cylindrical connection parts 1 and 21. Then, the upper and lower cylindrical connection parts 1 and 21 are butted against each other, and the outer peripheries of these cylindrical connection parts 1 and 21 are covered with a split cylindrical joint 6 (6a) which is divided into an arc shape and has bolt insertion holes drilled therethrough. By aligning each bolt insertion hole of this split cylindrical joint 6 (6a) with each of the above screw holes 3 and 23 and passing bolts 12 therethrough and tightening them, the above steel pipe piles 10 and 11 are connected to each other. With this configuration, each split cylindrical joint 6 (6a) and each bolt 12 fixed to the above cylindrical connection parts 1 and 21 do not protrude beyond the outer diameters of the steel pipe piles 10 and 11 to be connected.

[0003] Patent Document 2 (FIG. 21) will be described using the reference numerals in Patent Document 2. It directly butts and connects the lower steel pipe 3 and the upper steel pipe 4, and includes a short joint pipe 5 that fits into the inner surfaces of the upper and lower steel pipes 3 and 4. The joint pipe 5 is an aluminum pipe that is extruded into a cross-sectional shape having one or more partition-like wall portions (e.g., diameter wall 6) that traverse its cross-section, and is then anodized. Through bolts 8, which pass through the lower and upper steel pipes respectively, pass through bolt insertion holes made in the pipe wall and partition wall of the joint pipe 5 inside the steel pipe, and are fastened with nuts 9 that are screwed onto the tips of each through bolt, thereby joining the upper and lower steel pipes via the joint pipe. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 11-81304 [Patent Document 2] Japanese Patent Publication No. 2019-167758 [Overview of the project] [Problems that the invention aims to solve]

[0005] Patent Document 1 describes a design in which each divided cylindrical joint 6 (6a) and each bolt 12 fixed to the cylindrical connecting parts 1 and 21 are made so as not to protrude beyond the outer diameter of the steel pipe piles 10 and 11 being connected. However, the structure for achieving this is extremely complex, requires welding, resulting in poor workability and likely to be quite costly.

[0006] Patent Document 2 does not require welding and has a simple structure, but it still has a joint structure inside the steel pipe, so drilling holes in the steel pipe is necessary.

[0007] This invention was made to overcome the aforementioned drawbacks of conventional methods, and aims to enable fast and reliable steel pipe connection while eliminating the need for any processing such as drilling holes in the upper and lower steel pipes to be connected, and offering better workability compared to welding. [Means for solving the problem]

[0008] The invention of claim 1, which solves the above problem, In a steel pipe pile connection structure used when constructing steel pipe piles by connecting steel pipes of the same diameter in direct contact, Elbow-shaped locking members, having gaps that form a space relative to the outer surface of the pipes, are welded and fixed at multiple locations on the outer surface of the pipes, spaced apart in the circumferential direction, near the connection point of the upper and lower steel pipes that are butted together. It is equipped with multiple arc-shaped joint plates arranged in the circumferential direction, surrounding the outer circumference near the connection point of the upper and lower steel pipes when they are butted together. The joint plate has a vertically elongated opening that allows vertical relative movement with respect to the locking member, and through the opening, it is passed through the space of the separated portion of the locking member and pulled down to engage with the elbow-shaped locking member. A restraining piece is fitted into the space below the opening of the joint plate to restrain the downward movement of the joint plate. The joint plate is characterized by having a cover placed over its outer surface to press the restraining piece against it, and by fixing the cover to the joint plate at least in two places by screwing it into screw holes provided in the joint plate with bolts. Furthermore, the present invention relates to a mechanical joint between steel pipes in various types of steel pipe piles, and can be used, for example, when constructing steel pipe-wrapped concrete piles and various other types of steel pipe piles.

[0009] Claim 2 is characterized in that, in the steel pipe pile connection structure of Claim 1, there are four joint plates 4 arranged in the circumferential direction.

[0010] Claim 3 is a steel pipe pile connection structure according to claim 1 or 2, The aforementioned elbow-shaped locking member is characterized by a configuration in which two flat plates with the same width but different lengths are overlapped and welded together.

[0011] Claim 4 is a steel pipe pile connection structure according to any one of claims 1 to 3, The shape and dimensions of the restraining piece and the shape and dimensions of the opening of the joint plate are made the same. The restraining piece is characterized by using a square-hole material cut out to form the opening when manufacturing the joint plate. [Effects of the Invention]

[0012] In the invention of claim 1, when connecting the upper and lower steel pipes, The upper steel pipe 2 is placed on top of the lower steel pipe 1, and the upper and lower parts of the rectangular joint plate 4 with an arc-shaped cross-section are engaged with the elbow-shaped locking members on the outer circumference of the upper and lower steel pipes. Specifically, the joint plate 4 is hung so that its upper and lower openings 4a (see Figure 6) fit into the separated portions 3aa of the locking members 3 fixed to the outer circumference of the upper and lower steel pipes, respectively. At this time, the upper part of the opening 4a of the joint plate 4 is engaged with the separated portion 3aa of the locking member 3, but the lower part of the opening 4a is a space S. This space S is closed by the restraining plate 6 to restrain the joint plate 4 so that it does not move upward (does not come off). Next, a cover 7 is used to prevent the restraint plate 6 from coming off. The upper and lower steel pipes are then connected. As described above, the present invention eliminates the need for any processing such as drilling holes in the upper and lower steel pipes to be connected, and offers extremely good workability compared to welding, enabling fast and reliable steel pipe connection. Furthermore, since the joint plate 4 can be engaged with the elbow-shaped locking member 3 simply by sliding it downwards, the upper and lower steel pipes 1 and 2 can be connected with a single touch, making the connection work between the upper and lower steel pipes 1 and 2 efficient. Furthermore, the restraining plate 6, which restricts the downward movement of the joint plate 4, not only prevents the joint plate 4 from coming off but also ensures resistance to the pull-out of the pile.

[0013] According to Claim 2, since there are four joint plates 4 arranged in the circumferential direction, it is possible to effectively respond to the horizontal force acting on the steel pipe regardless of the direction.

[0014] As in Claim 3, if the elbow-shaped locking member is configured by overlapping and welding two flat plates with the same width and different lengths in the longitudinal direction, it is easy to set the depth in the vertical direction of the space between the separated parts of the locking member, or the gap interval with the outer surface of the pipe, to an appropriate value according to various conditions and situations.

[0015] According to Claim 4, since the shape and dimensions of the restraint piece are the same as those of the opening of the joint plate, the corner hole material cut out to form the opening when manufacturing the joint plate can be used as the restraint piece as it is. Therefore, the labor of separately manufacturing the restraint piece can be saved, and at the same time, the material cost can be saved, achieving two benefits at once.

Brief Description of the Drawings

[0016] [Figure 1] This shows an embodiment of the present invention, which is a diagram (the upper figure is a plan view and the lower figure is a front view) for explaining five steps ((a), (b), (c), (d), (e)) of the process for constructing the steel pipe pile connection structure of an embodiment. [Figure 2] It is an enlarged view (the upper figure is a plan view and the lower figure is a front view) for explaining the two steps (d) and (e) following the first three steps (a), (b), (c) in FIG. 1. [Figure 3] It is an enlarged cross-sectional view taken along the line A-A in FIG. 2(c). [Figure 4] (a), (b), (c) are respectively the front view, plan view, and right side view of the first flat plate constituting the elbow-shaped locking member in FIGS. 1 and 2. [Figure 5] (a), (b), (c) are respectively the front view, plan view, and right side view of the second flat plate constituting the elbow-shaped locking member in FIGS. 1 and 2. [Figure 6] (a) is the front view of the joint plate 4 in FIGS. 1 and 2, and (b) is the plan view. [Figure 7](a) is a front view of the restraint piece 6 in Figures 1 and 2, and (b) is a plan view. [Figure 8] (a) is a front view of cover 7 in Figures 1 and 2, and (b) is a top view. [Figure 9] This document describes the specific dimensions of the joint plates in an example manufactured from a seamless pipe material. (a) is a plan view showing the four joint plates in close contact with the outer surface of the steel pipe, (b) is a plan view showing the four joint plates along the outer surface of the seamless pipe material, and (c) is a front view of (b). [Figure 10] Figures 10 to 19 illustrate the process of connecting upper and lower steel pipes using the steel pipe pile connection structure of an embodiment of the present invention. Figure 10 shows the state in which the upper and lower steel pipes, to which the locking member 3 is attached, are about to be brought together. Note that in the illustration, only the vicinity of the connection part is shown, and the lengths of the steel pipes 1 and 2 to be connected are ignored. [Figure 11] This shows the upper and lower steel pipes 1 and 2, which are to be connected, butted against each other. [Figure 12] This shows the state in which the joint plate 4 is about to be attached to the connection point between the upper and lower steel pipes 1 and 2. [Figure 13] This shows the joint plate 4 attached to the connection point between the upper and lower steel pipes 1 and 2. [Figure 14] This shows the state in which the applied joint plate 4 has been pulled down. [Figure 15] This diagram shows the state in which the restraining piece 6 is being fitted into the opening at the bottom of the lowered joint plate 4. [Figure 16] This shows the restraint piece 6 fitted into the opening at the bottom of the joint plate 4. [Figure 17] This figure shows the state after preparing the cover 7 to prevent the restraining piece 6 from falling off. [Figure 18] This figure shows the cover 7 placed over the restraint piece. [Figure 19] This diagram shows the stage where the cover 7 is fixed to the joint plate 4 with bolts and flat washers. [Figure 20] This is a diagram from Patent Document 1. [Figure 21]This is a diagram from Patent Document 2. [Modes for carrying out the invention]

[0017] The embodiments for implementing the steel pipe pile connection structure of the present invention will be described below with reference to the drawings. [Examples]

[0018] Figure 1 shows one embodiment of the present invention, illustrating the steps (a), (b), (c), (d), and (e) for constructing the steel pipe pile connection structure of one embodiment. In each of these steps, the upper figure is a plan view (a), and the lower figure is a front view. Figure 2 is an enlarged view of (d) and (e) in Figure 1. Figure 3 is an enlarged cross-sectional view of AA in Figure 2(e). Figures 10 to 19 show the specific procedure for constructing the steel pipe pile connection structure of the present invention (details to be described later).

[0019] The steel pipe pile connection structure in this embodiment is a steel pipe pile connection structure that, when butting upper and lower steel pipes of the same diameter together, does not require processing of the steel pipes themselves and connects them without any parts being present inside the steel pipes. Near the connection point of the upper and lower steel pipes 1 and 2 that are directly butted together, an elbow-shaped locking member 3 is welded and fixed to the outer surface of the pipe, having a gap 3aa that forms a space with respect to the outer surface of the pipe. In this embodiment, four locking members 3 are provided in the circumferential direction. The elbow-shaped locking member 3 in this embodiment is made by overlapping and welding together two flat plates 3a and 3b that have the same width but different vertical lengths, with the upper part of the vertically elongated flat plate 3a forming a space 3aa that separates it from the outer surface of the pipe. In the illustrated example, four arc-shaped joint plates 4 surround the outer circumference near the connection point of the upper and lower steel pipes 1 and 2 when they are joined together. The joint plate 4 has a vertically elongated opening 4a that allows vertical relative movement with respect to the locking member 3. The opening 4a allows the joint plate 4 to pass through the space of the separated portion 3aa of the locking member 3, be pulled down, and engage with the locking member 3. This causes the joint plate 4 to engage with the steel pipes 1 and 2. A restraining piece 6 is fitted into the space below the opening a of the joint plate 4 to restrain the upward movement of the joint plate 4. Furthermore, the joint plate is equipped with a cover 7 that presses the restraining piece 6 against its outer surface, and this cover 7 is fixed to the joint plate 4 by a bolt 9 that is screwed into a screw hole 4b provided in the joint plate 4. As a result, there is no risk of the joint plate 4 coming off the restraining piece 6 fixed to the steel pipes 1 and 2, and the upper and lower steel pipes 1 and 2 can be stably joined together.

[0020] The steel pipe pile connection structure in this embodiment requires no processing such as drilling holes in the upper and lower steel pipes 1 and 2 to be connected, and offers extremely good workability compared to welding, enabling fast and reliable steel pipe connection. Furthermore, since the joint plate 4 can be engaged with the elbow-shaped locking member 3 simply by sliding it downwards, the upper and lower steel pipes 1 and 2 can be connected with a single touch, making the connection work between the upper and lower steel pipes 1 and 2 efficient. Furthermore, the restraining plate 6, which restricts the downward movement of the joint plate 4, not only prevents the joint plate 4 from coming off but also ensures resistance to the pull-out of the pile. [Examples]

[0021] Figures 10 to 19 show specific examples of how the upper and lower steel pipes 1 and 2 are connected. Figure 10 shows the upper and lower steel pipes 1 and 2 to be connected. Note that in the illustration, the lengths of the steel pipes 1 and 2 to be connected are ignored, and only the vicinity of the connection point is shown. As shown in Figure 11, the upper and lower steel pipes 1 and 2 are butted together with their rotational directions aligned. Prepare the joint plate 4 as shown in Figure 12. Next, as shown in Figure 13, the joint plate 4 is placed over the connection point between the upper and lower steel pipes. Next, pull down the joint plate 4 as shown in Figure 14. Next, prepare the locking piece as shown in Figure 15. Next, apply the locking piece as shown in Figure 16. Next, prepare the cover as shown in Figure 17. Next, place the cover over the locking piece as shown in Figure 18. Next, secure the cover with hexagonal bolts and flat washers as shown in Figure 19. With the above steps completed, the connection work of the upper and lower steel pipes for one joint plate 4 is finished. Next, although the diagram is omitted, performing the same connection work at the remaining three locations completes the connection of the upper and lower steel pipes 1 and 2. [Explanation of Symbols]

[0022] 1. Upper steel pipe 2. Lower steel pipe 3. Elbow-shaped locking member 3a Long flat plate 3b short plate 3aa Separation part 4. Joint Plate 4a aperture 4b Screw hole 6 restraint piece 7 Cover 9 volts

Claims

1. In a steel pipe pile connection structure used when constructing steel pipe piles by connecting steel pipes of the same diameter in direct contact, Elbow-shaped locking members, having gaps that form a space relative to the outer surface of the pipes, are welded and fixed at multiple locations on the outer surface of the pipes, spaced apart in the circumferential direction, near the connection point of the upper and lower steel pipes that are butted together. A steel pipe pile connection structure characterized by comprising a plurality of arc-shaped joint plates arranged in the circumferential direction, surrounding the outer circumference near the connection portion of upper and lower steel pipes in a butted state, the joint plates having elongated vertical openings that allow relative vertical movement with respect to the locking member, passing through the space of the separated portion of the locking member through the openings and being pulled down to engage with the elbow-shaped locking member, a restraining piece fitted into the space below the opening of the joint plate to restrain the downward movement of the joint plate, a cover placed over the outer surface of the joint plate to press the restraining piece from its outer surface, and the cover being fixed to the joint plate at least in two places by screwing it into screw holes provided in the joint plate with bolts.

2. The steel pipe pile connection structure according to claim 1, characterized in that the joint plates 4 are four plates arranged in the circumferential direction.

3. The steel pipe pile connection structure according to claim 1 or 2, characterized in that the elbow-shaped locking member is constructed by overlapping and welding together two flat plates that have the same width but different lengths.

4. The steel pipe pile connection structure according to claim 1 or 2, characterized in that the restraining piece is made of square-hole material cut out to form the opening when the joint plate is manufactured.

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