JP2009299298A - Mechanical joint of steel pipe pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical joint which gives consideration to bending moment produced by earthquakes, a strong wind and the like. <P>SOLUTION: An outer joint material 3 is fixed to a lower steel pipe pile 2; an inner joint material 4 is fixed to an upper steel pipe pile 1; and pin insertion holes are drilled in such a manner as to be identically arranged in the circumferential directions of the outer and inner joint materials 3 and 4, respectively. The inner joint material 4 is inserted and fitted into the outer joint material 3; and a bolt 34 is inserted into each of bolt insertion holes 35 and 36. When a compressive force acts on the pair of steel pipe piles, an outer peripheral surface of the inner joint material 4 and that of the outer joint material 3 are tightened with the bolt 34, so that the inner and outer joint materials 4 and 3 can be coupled together. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a mechanical joint for steel pipe piles, and more particularly to a mechanical joint for steel pipe piles which is easy to manufacture and can be provided at a low cost and has a sufficient strength for practical use.

  There are steel pipe piles and concrete piles as ready-made piles used in various civil engineering works, both of which may be joined as necessary. Generally, welding is often used for joining piles in the field, but it is difficult to ensure the welding quality, the work is subject to the weather, and the welding work takes a long time. In concrete piles, joints using mechanical joints that do not require on-site welding have recently been implemented frequently.

  Also, in the field of concrete piles, the background of the spread of mechanical joints is that steel materials that are several times stronger than concrete can be used as joint materials, and generally there are steel end plates at both ends of concrete piles. Since this can be used as a part of the joint material, there are reasons that the overall cost can be kept low.

On the other hand, in the case of steel pipe piles, steel is used as a joint material, as is the case with steel pipe piles, but in order to make the joint part strength equal to or higher than that of the steel pipe pile body, the use of high-quality, high-strength steel materials and complex structures are adopted. As a result, it is inevitable that the manufacturing cost of the joint will increase with this, and the spread is hindered.
JP 2006-28913 A JP 2001-11850 A JP 2006-207117 A None

  Patent Documents 1 to 3 all relate to mechanical joints for steel pipe piles. In Patent Document 1, circular protrusions are alternately provided in the circumferential direction on the outer surface of the male cylinder and the inner surface of the female cylinder, respectively. A joint is disclosed in which a cylinder is inserted into a female cylinder and then rotated and joined. In this joint, the tensile force is transmitted by contact between the arc-shaped protrusions (gears), and the transmission capability of the tensile force is large and the bending moment is also strong. However, it is unrealistic to fix the arc-shaped projections to the joint body by welding. Normally, a thick cylindrical body is cut with a lathe to form arc-shaped projections. It is clear that the cutting of the cylindrical body in the axial direction is extremely inefficient and is the biggest factor of the high cost.

  In this joint, the rotational torque is transmitted by a key provided between the male and female cylinders. However, since the key in this case is not a simple cylindrical pin, the manufacturing cost of the key and its insertion hole is high. Inevitably, this also increases the overall cost. Taking these points into consideration, the mechanical joint disclosed in Patent Document 1 is difficult in cost.

  On the other hand, in Patent Document 2, an inner joint pipe having a pin insertion hole or a plurality of strip-shaped flat plates are inserted into an outer joint pipe having the same pin insertion hole, and then a pin is inserted into both pin insertion holes to be coupled. A mechanical joint of structure is disclosed. In this joint, the axial force (tensile force and compressive force) of the steel pipe pile is transmitted through the shearing force of the pin member, but a large compressive force or tensile force can be generated only by the pin member. It was impossible in terms of strength to be transmitted as will be described later.

  In this joint, the inner joint pipe is structured to be fixed to the inner surface of the steel pipe end, and in the drawing, both ends are fillet welded, and a notch is provided at the lower part of the inner joint pipe to weld. An example of increasing the length of the part is shown, but in the former case, the welding work inside the steel pipe is difficult unless the pipe diameter is sufficiently large, and because the fillet weld is used, the welding strength is There is a problem that it is difficult to secure, but the latter is shown as a supplement to this, but as the weld length becomes longer, it is natural that workability deteriorates, and as a result, there is a disadvantage that costs increase. It was.

  On the other hand, when a strip-shaped flat plate is used as an alternative to the inner joint pipe, the same problem as in the case of the welding of the notch described above occurs, and the torsional strength and rigidity of the strip-shaped section are significantly higher than those of the annular section. Inferiority, there was a drawback that the steel pipe body could not have the same strength unless the thickness was made very large. Furthermore, in order to remedy this drawback, a technique for joining an inner joint pipe and a steel pipe via a thick short pipe is also disclosed, but the procurement cost and welding cost of the thick short pipe are excessive. As a result, there is a drawback that the joint becomes expensive. From these points, the joint disclosed in Patent Document 2 cannot be said to have sufficient practicality.

  Furthermore, Patent Document 3 discloses a hole provided at the boundary of the concavo-convex part after fitting the concavo-convex part of the first joint (upper joint) and the second joint (lower joint) provided with concavo-convex at the end part. A mechanical joint having a structure in which a pin is inserted is disclosed, and although it differs greatly in form from the mechanical joint disclosed in Patent Document 2, not only the axial direction but also the bending moment depends on the pin. The point of trying to transmit is uniform, and in that sense, it has the same problems as the mechanical joint disclosed in Patent Document 2 described above.

  In addition, in this joint, the pin facing the shear direction cannot exhibit shear resistance, and the cross-sectional area of the concavo-convex portion is only half that of the upper and lower portions, so that sufficient shear strength cannot be ensured. There was a problem. Therefore, the joint disclosed in Patent Document 3 is not sufficient in strength, and must be said to have a practical problem.

  By the way, the force acting on the foundation pile is usually compressive force, tensile force, bending moment, shearing force, rotational torque (torsional shearing force). Except for special cases, it is the compressive force in the direction of the pile axis, and large pulling force, bending moment, and shearing force are applied to the foundation pile only for a short period of time such as an earthquake or strong wind. Further, the pulling force is usually as small as a fraction of the compression force, and the frequency of occurrence is low. Furthermore, even when a bending moment is applied, it is normal that the bending moment does not act on the pile alone but acts simultaneously with the compressive force. In other words, when the foundation pile is viewed as an annular cross section, the portion where the tensile stress is generated is only a small portion of the circumference, and the value is small, and the compressive stress is generated mostly. It will be.

  On the other hand, when a rotary penetrating pile is constructed, a rotational torque of the same magnitude as the torsional strength of steel pipe piles is frequently generated, so when using a joint for this rotary penetrating pile, it is necessary to withstand this torque. When trying to counter this rotational torque with only the horizontal shear resistance of the pin, the shearing force of the pin against the rotational torque equivalent to the torsional strength of the steel pipe resists the tensile force equivalent to the tensile strength of the steel pipe. It has hitherto been known that it is theoretically only 1/3 compared to the shearing force of the pin.

  From the consideration of the general acting force of the foundation pile described above, the present inventor is more rational that the compressive force is transmitted by contacting the member directly rather than via a pin, as will be described later. It has been found that a pulling force with a low occurrence frequency and a small force is rational in terms of mechanism when transmitted through a pin. Based on the above findings, the present inventor has conducted research to solve the problems inherent in mechanical joints used for joining steel pipe piles. Moreover, a mechanical joint that can be manufactured at low cost was proposed as Japanese Patent Application No. 2007-190470.

  As shown in FIGS. 1 to 5, the mechanical joint proposed as Japanese Patent Application No. 2007-190470 has a thick annular ring at right angles from one end edge of the base portion (8) having a thick cylindrical shape toward the outside. The collar portion (13) has a cylindrical shape with a steel collar that is integrally extended. The outer diameter of the collar portion (13) is substantially the same as the outer diameter of the pair of steel pipe piles to be joined. The outer diameter of (8) is formed so as to be slightly smaller than the inner diameter of the outer joint material (3), and the end face of one steel pipe pile coincides with the axial center of the end face of the collar part (13). A plurality of pin insertion holes (10) are formed in the peripheral wall (16) of the base portion (8) in a radial direction in a direction perpendicular to the axial center at intervals. Inner joint material (4); The outer diameter of the inner pipe material (4) is substantially the same as the outer diameter of the steel pipe pile to be joined. Each of which has an inner diameter slightly larger than the outer diameter of the portion (8), and the end face of the other steel pipe pile is weld-fixed in a state in which its axial center coincides, and the base portion of the inner joint material (4) ( 8) A thick cylindrical outer joint material (3) made of steel in which a pin insertion hole (12) of the same diameter is drilled at a location corresponding to the pin insertion hole (10) drilled in 8); The base portion (8) of the inner joint material (4) is inserted into the inner diameter side of the outer joint material (3), the pin (18) is inserted into each pin insertion hole (10) (12), and the inner joint material (4 ) And the outer joint material (3).

  This mechanical joint is welded to the lower end of the upper steel pipe pile 1 with the upper surface of the collar portion 13 of the inner joint material 4 in a state where the axial center thereof coincides, and to the upper surface of the lower steel pipe pile 2 the lower end surface of the outer joint material 3. And the base 8 of the inner joint material 4 is inserted into the inner diameter side of the outer joint material 3 fixed to the upper surface of the lower steel pipe pile 2, and the respective pin insertion holes 10, 12 are welded. The pin 18 is inserted here and the lower steel pipe pile 2 and the upper steel pipe pile 1 are connected to each other, and the transmission characteristics in the case of contact between a pair of joints and via the pin are skillful. When the compressive force is applied, the contact between the flange of the inner joint material and the upper end surface of the outer joint material is used. When the tensile force is applied, the force is transmitted by the pin. With a simple structure without waste considering the load conditions of piles, while having sufficient reliability, Can be manufactured at a cost have, attaching binding work at the site can also performed very easily, and has high practicality. However, in the mechanical joint proposed as this Japanese Patent Application No. 2007-190470, no special consideration has been given to the bending moment acting on the steel pipe pile connected by this mechanical joint. As described above, the force that always acts on the foundation pile is centered on the compressive force in the direction of the pile axis, and the bending moment acts only for a short time in the event of an abnormality such as an earthquake or strong wind. The main reason is that it is sufficiently smaller than the bending strength of steel pipes. When a large bending moment is applied to the steel pipe joined by the mechanical joint of Japanese Patent Application No. 2007-190470, as shown in FIG. 6 on the compression side and as shown in FIG. A "<"-shaped deformation accompanied by the separation of the joint material occurs. 6 and 7 illustrate the deformation state when the bending moment is applied in an easy-to-understand manner, and the deformation is exaggerated. Of course, the actual deformation is smaller than this. Incidentally, a mechanical joint manufactured under a predetermined strength design has the same bending strength (final strength) as that of a steel pipe, but the bending displacement becomes larger than that of the steel pipe. For example, a steel pipe and a steel pipe to which a mechanical joint according to Japanese Patent Application No. 2007-190470 having a bending strength equivalent to that of the steel pipe is prepared, and a bending load is applied to them as shown in FIG. When the bending test is performed and compared, as shown in the graph of FIG. 9, in the case of the steel pipe with a joint, the displacement at the center portion becomes larger than the case of the steel pipe alone with respect to the same bending moment. That is, in the case of a steel pipe with a joint, the bending rigidity as an apparent pile is smaller than that of a steel pipe alone. In general, a large bending moment is unlikely to act on the joint, and the above phenomenon is unlikely to be a problem, but when a joint is installed near a pile head where a large bending moment occurs during an earthquake, This is a problem that cannot be ignored in design. The present inventor conducted research to eliminate the phenomenon of apparent bending rigidity reduction at the time of bending moment action in the mechanical joint proposed as Japanese Patent Application No. 2007-190470. The present inventors have succeeded in developing a mechanical joint that can be used, and propose it as the present invention.

  Thick-cylindrical cylindrical portion with a thick annular ring (13) integrally extending perpendicularly outward from one end of the thick cylindrical base (8) The outer diameter of the collar portion (13) is substantially the same as the outer diameter of the pair of steel pipe piles to be joined, and the outer diameter of the base portion (8) is slightly smaller than the inner diameter of the outer joint material (3). And the end face of one of the steel pipe piles is welded and fixed to the end face of the collar part (13) in a state in which its axis is aligned, and the shaft (1) is attached to the peripheral wall (16) of the base part (8). An inner joint material (4) in which a plurality of bolt insertion holes (35) are drilled at intervals from each other in a direction perpendicular to the center; an outer diameter substantially the same as an outer diameter of a steel pipe pile to be joined; The end face of the other steel pipe pile, each having an inner diameter slightly larger than the outer diameter of the base (8) of the inner joint material (4) A bolt insertion hole (36) is formed at a position corresponding to the bolt insertion hole (35) formed in the base portion (8) of the inner joint material (4) while being welded and fixed with the axial centers thereof matched. A steel-made cylindrical outer joint material (3) which is perforated, and the base (8) of the inner joint material (4) is inserted into the inner diameter side of the outer joint material (3). The bolts (34) are inserted into the bolt insertion holes (35) and (36), and the outer peripheral surface of the inner joint material and the inner peripheral surface of the outer joint material are tightened with bolts, whereby the inner joint material (4) and the outer joint material ( The above problem was solved by combining 3).

  The upper surface of the flange portion 13 of the inner joint material 4 is welded to the lower end of the upper steel pipe pile 1 in a state where the axis is aligned, and the lower end surface of the outer joint material 3 is aligned with the upper surface of the lower steel pipe pile 2 The base 8 of the inner joint material 4 is inserted into the inner diameter side of the outer joint material 3 fixed to the upper surface of the lower steel pipe pile 2 and the positions of the respective bolt insertion holes 35 and 36 are aligned. The bolt 34 is inserted into the lower steel pipe pile 2 and the upper steel pipe pile 1 is connected. In this state, when a compressive force is applied downward from the upper steel pipe pile 1, the compressive force is directly transmitted from the collar portion 13 of the inner joint member 4 to the end face of the outer joint member 3, so that a very simple force can be obtained. It becomes a transmission path. Therefore, bearing stress is generated in the abutting portions, but the distribution is uniform in the thickness direction, and the abutting area is equal to the cross-sectional area of the outer joint material 3 and is sufficiently wide, so that a large bearing stress difference occurs. No compression occurs, and the compressive force is transmitted to the lower steel pipe pile 2 without difficulty. On the other hand, when a tensile force is applied from the upper steel pipe pile 1, the tensile force is transmitted from the flange portion 13 of the inner joint material 4 to the base portion 8, and then transmitted to the bolt 34 as a vertical shearing force, and further to the outer joint material 3. It will be transmitted as a pulling force. In this case, the degree of bearing stress generated in each contact area is much larger than the above-mentioned compressive force when compared per unit area, but the tensile force acts on the foundation pile such as earthquake and strong wind It is only a short time at the time of abnormality, and the pulling force is usually less than a fraction of that of the compressive force, and its frequency of occurrence is low. Therefore, the bolt 34 and its contact portion sufficiently withstand this bearing stress. It is possible to reliably transmit the pulling force.

  Further, when a bending moment is applied, when viewed from the annular cross section, a compressive force as shown in FIG. 6 is applied to substantially half of the joint, and a tensile force as shown in FIG. However, since the outer joint material 3 and the inner joint material 4 are fastened by bolts 34 and integrated in terms of strength, the transmission of these forces is the same as in the case of a steel pipe alone. Therefore, unlike the case shown in FIGS. 6 and 7, the outer joint material 3 and the inner joint material 4 are not separated and deformed into a “<” shape, and both are resistant to bending moment as a unit. Become. On the other hand, when a shearing force acts, the shearing force from the upper steel pipe pile 1 is transmitted to the base 8 of the inner joint material 4 via the collar portion 13 of the inner joint material 4, and this base 8 presses the outer joint material 3. Is transmitted to this. Further, when rotational torque (torsional shearing force) acts, it is transmitted as a torsional shearing force from the collar portion 13 of the inner joint material 4 to the base portion 8, and then as a horizontal shearing force to the bolt 34. It is transmitted as torsional shear force. In addition, during the construction of the rotary penetration pile, a rotational torque with a value similar to that of the steel pipe pile is frequently generated. Compared to the shearing force of the bolt 34 that opposes the tensile force equivalent to the tensile strength, the bolt 34 can sufficiently resist this rotational torque because it is theoretically only √1 / 3.

  As described above, the mechanical joint for joining steel pipe piles according to the present invention brings the end surfaces of the outer joint material 3 and the inner joint material 4 into contact with each other, and tightens both side surfaces with bolts to strengthen the strength of the two. When the compressive force is applied, the force is transmitted by the contact between the flange portion 13 of the inner joint material 4 and the upper end surface 6 of the outer joint material 3, and the tension is caused by the bending moment. When force and compressive force are applied, the outer joint material 3 and the inner joint material 4 are joined to each other by bolts, so they are difficult to be separated from each other, and the decrease in apparent rigidity is greatly reduced. It can withstand external bending moments. In this way, it is possible to manufacture at a low cost while having sufficient reliability with a simple structure with no waste considering the load conditions of the actual foundation pile, and it is extremely easy to install and connect on site. It has an effect that can be implemented and has high practicality.

  The greatest feature lies in that the side surfaces of the outer joint material and the inner joint material that are formed into a cylindrical shape are joined together by fastening them with bolts.

  FIG. 10 is a perspective view of Embodiment 1 of a mechanical joint for joining steel pipe piles according to the present invention, FIG. 11 is a perspective view in a state of being fixed to the steel pipe pile, and FIG. 13 is a cross-sectional view taken along line AA in FIG. 12, and FIG. 14 is a cross-sectional view taken along line BB in FIG.

  In the figure, 1 is an upper steel pipe pile to be joined, and 2 is a lower steel pipe pile. The mechanical joint for joining steel pipe piles according to the present invention is used to join the lower end of the upper steel pipe pile 1 and the upper end of the lower steel pipe pile 2 in series, and is made of a steel inner joint material 4, The outer joint material 3 and a plurality of bolts 34 are used.

  The inner joint member 4 is a cylindrical member with a flange made of steel, in which a thick annular collar 13 is integrally extended perpendicularly from the upper edge of the base 8 having a thick cylindrical shape toward the outside. The outer diameter of the collar portion 13 is substantially the same as the outer diameter of the upper steel pipe pile 1, and the outer diameter of the base portion 8 is formed to be slightly smaller than the inner diameter of the lower steel pipe pile 2, respectively. The lower end surface of the upper steel pipe pile 1 is fixed to the upper surface 5 of 13 by welding in a state where the axes are aligned. Further, a plurality of bolt insertion holes 35 are formed in the peripheral wall 16 of the base portion 8 at intervals from each other in a direction perpendicular to the axis.

  On the other hand, the outer joint material 3 is a steel thick cylindrical member having an outer diameter substantially the same as the outer diameter of the lower steel pipe pile 2 and an inner diameter slightly larger than the outer diameter of the base 8 of the inner joint material 4. When the base portion 8 of the inner joint material 4 is inserted into the inner diameter side of the outer joint material 3, bolts of the same diameter are provided at locations corresponding to the bolt insertion holes 35 formed in the base portion 8 of the inner joint material 4. Insertion holes 36 are formed, and bolts 34 are inserted into these bolt insertion holes 35, 36, and the nut 21 is screwed from the inside of the inner joint material 4, whereby the inner peripheral surface of the outer joint material 3 and the inner joint material The outer peripheral surface of 4 is firmly tightened to couple them together. In the figure, reference numeral 22 denotes a head of the bolt 34. And the lower end of this outer joint material 3 is fixed to the upper end surface 6 of the lower steel pipe pile 2 by welding in a state in which its axial center coincides. In this embodiment, the inner joint material 4 is welded and fixed to the upper steel pipe pile 1 and the outer joint material 3 is welded and fixed to the lower steel pipe pile 2. The joint material 3 may be fixed to the lower steel pipe pile 2 by welding.

  The outer joint material 3 may be a short cut of a suitable ready-made steel pipe, or may be manufactured by forging or cast steel. If the roundness and dimensions on the inner diameter side are inappropriate, the inner diameter side is cut with a lathe. You may do it. On the other hand, the inner joint material 4 is obtained by cutting a thin steel pipe such as a seamless steel pipe or a centrifugal cast steel pipe into a short length or by cutting the lower part of the outer peripheral surface of a cylindrical body manufactured by forging with a numerically controlled lathe. You may use what gave the shape process.

  These cutting processes are different from the case where gears are formed in the tube axis direction, etc., and since they have a constant shape in the circumferential direction, if the blade of the numerically controlled lathe is applied while the material is rotated, it is easy in a short time. Can be implemented. Further, since the bolt insertion holes 35 and 36 have a circular cross section, they can be accurately formed in a short time by using a horizontal drilling machine capable of numerical control operation. The bolts 34 and the nuts 21 to be screwed to the bolts 34 can be ready-made as long as they satisfy the required strength.

  Further, as described above, the inner joint material 4 is fixed to the lower end of the upper steel pipe pile 1 and the outer joint material 3 is fixed to the upper end of the lower steel pipe pile 2 by welding, but as shown in FIG. By chamfering the outer edge upper portion of the flange portion 13 of the joint material 4 and the outer edge lower portion of the outer joint material 3 to form the slopes 19 and 20 for groove welding, the welding operation can be performed more easily, reliably and firmly. More convenient. The slopes 19 and 20 for groove welding can be easily formed by a lathe. 10 to 14, the head portion 22 of the bolt 34 projects outward from the outer surface of the outer joint material 3, and the existing bolt can be used as it is, and the processing is also easy. If the head 22 of the bolt 34 is not allowed to protrude outward from the outer surface of the outer joint material 3 in terms of design and construction, it is the most basic structure. As shown in FIG. 4, a headless bolt 37 having screw grooves 23 and 24 formed at both ends is used, and a screw groove 25 is formed in the bolt insertion hole 36 of the outer joint material 3, so that the screw groove 25 of the outer joint material 3 is formed. And the screw groove 24 of the headless bolt 37 are screwed together, and the nut 21 is screwed into the screw groove 23 protruding inward from the inner joint material 4, thereby tightening the outer joint material 3 and the inner joint material 4. You may make it combine. In the figure, reference numeral 26 denotes an engagement hole for engaging a tool for rotating the headless bolt 24. Further, as shown in FIG. 17, screw grooves 27 and 28 are formed in the bolt insertion hole 35 of the inner joint material 4 and the bolt insertion hole 36 of the outer joint material 3, and the screw groove 29 is formed over the entire circumferential surface. The headless bolt 30 may be prepared, and the inner surface of the outer joint material 3 and the outer peripheral surface of the inner joint material 4 may be coupled by the headless bolt 30. Furthermore, not only the bolt insertion holes 35 and 36 for connecting the outer joint material 3 and the inner joint material 4 are arranged in a line, but also the bolt insertion holes 35 and 36 are arranged in two upper and lower stages as shown in FIG. It may be arranged. In this way, when the bolt insertion holes 35 and 36 are arranged in two upper and lower stages, the lengths of the outer joint material 3 and the inner joint material 4 must be made longer than in the case of one row arrangement. There is an advantage that the deformation of the “<” shape as shown in FIG. 10 to 14 and FIG. 16, the nut 21 is used, and the nut 21 is located inside the inner joint material 4. Therefore, the screw 21 is screwed into the bolt 34. Although it is difficult to hold the position properly, as shown in FIG. 18, a screw groove 27 is formed in the bolt insertion hole 35 of the inner joint member 4 and is formed on the outer peripheral surface of the headed bolt 34. If the screw groove is screwed into the screw groove 27 formed in the bolt insertion hole 35 so that the inner surface of the outer joint material 3 and the outer peripheral surface of the inner joint material 4 are tightened and coupled, Since it is not necessary to use a nut that is troublesome to maintain the position during work, workability is improved. Further, as shown in FIG. 19, the nut 21 may be fixed in advance at an appropriate position by an adhesive means 38 such as welding or adhesive. In this case, the screwing operation with the bolt 34 is performed. It becomes easy to do. Further, as shown in FIG. 20, a box-shaped nut holder 31 of a size that does not allow the nut 21 to rotate freely is fixed inside the bolt insertion hole 35, and the nut 21 may be put therein. Well, in this case, since the taper is formed on the tip side of the bolt 34, the tip side is smoothly guided to the screw hole of the nut 21 in the nut holder 31 as the bolt 34 rotates, The nut 21 is attracted to the bolt 34 and both are firmly coupled, so that the bolt fastening operation can be performed more easily. The nut holder 31 can be manufactured at low cost by bending a thin steel plate or by cutting a square pipe into short pieces and attaching a lid to the nut holder 31. Further, as shown in FIG. 21, an annular nut holding ring 32 is concentrically fixed via a support member 33 inside the inner joint member 4 at a distance from the bolt insertion hole 35. The nut 21 may be fixed to the nut holding ring 32. In this case, the bolt 34 and the nut 21 can be easily screwed together. As described above, the mechanical joint for joining steel pipe piles according to the present invention can maintain not only the compressive force and tensile force but also the necessary strength and rigidity even when a bending moment is applied, and has sufficient reliability. It can be manufactured at a low cost while having a low profile, and it is easy to mount and connect on site, and has extremely high practicality.

  It can be used in various civil engineering works using foundation piles.

The perspective view of Example 1 of the mechanical coupling for joining of the steel pipe pile proposed by Japanese Patent Application No. 2007-190470. Similarly, the perspective view of the state which adhered to the steel pipe pile, respectively. Similarly, the perspective view of the state which joined the steel pipe pile. FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. CC sectional view taken on the line CC in FIG. Similarly, sectional drawing of the compression side for demonstrating the deformation | transformation condition when a bending moment acts. Similarly, sectional drawing on the pulling side for explaining a deformation situation when a bending moment is applied. Explanatory drawing explaining the method of the load test implemented in order to investigate the influence of a bending moment. The graph which showed the result of the load test shown in FIG. The perspective view of Example 1 of the mechanical joint for joining of a steel pipe pile. Similarly, the perspective view of the state which adhered to the steel pipe pile, respectively. Similarly, the perspective view of the state which joined the steel pipe pile. FIG. 13 is a sectional view taken along line BB in FIG. 12. FIG. 14 is a sectional view taken along the line DD in FIG. 13. The fragmentary sectional view of the Example which provided the slope for groove welding. The fragmentary sectional view of the other Example of the mechanical joint for joining of the steel pipe pile concerning this invention. Similarly, the fragmentary sectional view of other Examples. The fragmentary sectional view of the Example which abbreviate | omitted the nut 21. FIG. The fragmentary sectional view of the Example which provided the drop-off prevention means of the nut 21. FIG. Similarly, the fragmentary sectional view of the Example which provided the other drop-off prevention means of the nut 21. FIG. Similarly, the fragmentary sectional view of the Example which provided another drop-off prevention means of the nut 21. FIG. The perspective view of the waist | lumbar part of the Example which provided the bolt insertion hole 35 and 36 in two steps, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper steel pipe pile 2 Lower steel pipe pile 3 Outer joint material 4 Inner joint material 5 Upper surface 6 Upper end surface 8 Base part 10 Pin insertion hole 12 Pin insertion hole 13 Collar part 16 Perimeter wall 18 Pin 19 Slope 20 for groove welding For groove welding 21 Nut 22 Head 23 Screw groove 24 Screw groove 25 Screw groove 26 Engagement hole 27 Screw groove 28 Screw groove 29 Screw groove 30 Headless bolt 31 Nut holder 32 Nut holding ring 33 Support material 34 Bolt 35 Bolt insertion hole 36 Bolt insertion hole 37 Headless bolt 38 Adhesive means

Claims (7)

The outer diameter of the collar is made of a steel collar with a thick-walled annular collar integrally extending perpendicularly from one end of the thick-walled base to the outside. Is formed so that the outer diameter of the base is slightly smaller than the inner diameter of the outer joint material, approximately the same as the outer diameter of the pair of steel pipe piles to be joined. The pile end face is welded and fixed with its axial center aligned, and a plurality of bolt insertion holes are formed at intervals in the peripheral wall of the base in a direction perpendicular to the axial center. Inner joint material; each has an outer diameter substantially the same as the outer diameter of the steel pipe pile to be joined, and an inner diameter slightly larger than the outer diameter of the base of the inner joint material, and the end face of the other steel pipe pile has its axis center It is welded and fixed in a matched state, and is drilled in the base of the inner joint material A thick cylindrical outer joint material made of steel having a bolt insertion hole of the same diameter at a position corresponding to the bolt insertion hole; and the base of the inner joint material is inserted into the inner diameter side of the outer joint material. The inner joint material and the outer joint material are joined by inserting bolts into the respective bolt insertion holes and tightening the outer peripheral surface of the inner joint material and the inner peripheral surface of the outer joint material with bolts. A steel pipe pile mechanical joint. 2. The outer joint material and the inner joint material are fastened and joined by positioning a nut inside the inner joint material and screwing a thread groove of a headed bolt into the nut. Steel pipe pile mechanical joint. Tighten the outer joint material and the inner joint material by forming a screw groove in the bolt insertion hole of the inner joint material and screwing the screw groove of the headed bolt into the screw groove formed in this bolt insertion hole. The mechanical joint for steel pipe piles according to claim 1, wherein the mechanical joints are joined together. A screw groove is formed in the inner surface of the bolt insertion hole of the outer joint material, and a screw groove in the rear part of the headless bolt in which the screw groove is formed in the front part and the rear part, respectively. So that the rear end surface of the headless bolt is substantially flush with the outer periphery of the outer joint material, and a nut positioned inside the inner joint material is screwed into the thread groove of the front portion. The mechanical joint for steel pipe piles according to claim 2, wherein the outer joint material and the inner joint material are fastened and joined together. Threaded grooves are formed on the inner surfaces of the bolt insertion holes of the outer joint material and the bolt insertion holes of the inner joint material, and the headless bolts with the thread grooves formed on the outer periphery are connected to the outer surface of the outer joint material. 3. The steel pipe pile according to claim 2, wherein the outer joint material and the inner joint material are coupled by screwing into the screw grooves of the both bolt insertion holes so as to be flush with each other. Mechanical coupling. 3. The steel pipe pile mechanical joint according to claim 2, wherein the nut is held at a position facing the bolt insertion hole inside the inner joint material. The steel pipe pile mechanical joint according to claim 2, wherein the bolt insertion holes of the outer joint material and the bolt insertion holes of the inner joint material are arranged in two stages.

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