JP2010168789A - Mechanical coupling for steel pipe pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical coupling for a steel pipe pile which allows a steel cylindrical body to be extracted at low cost and is increased in reliability though the cost for manufacture is low. <P>SOLUTION: This mechanical coupling for the steel pipe pile comprises an outer joint pipe 3 which is cylindrical, the diameter of which is generally equal to those of steel pipe piles 1, 2 to be joined to each other, and which has a plurality of holes 6, 7 in the peripheral wall, an inner joint pipe 4 which is cylindrical, the outer diameter of which is slightly smaller than the inner diameter of the outer joint pipe, and which has a hole of the same diameter communicating with the hole of the outer joint pipe, a steel outer ring 9 the outer diameter of which is generally equal to that of the steel pipe piles and the inner diameter of which is slightly larger than the outer diameter of the inner joint pipe, and the steel cylindrical body 8 the outer diameter of which is slightly smaller than the hole. The outer joint pipe is affixed to the end surface of one steel pipe pile 2, and the steel outer ring is inserted along the outer periphery of the inner joint pipe. The inside of the gap surrounded by the steel pipe piles, the steel outer ring, and the inner joint pipe is welded, the inner joint pipe is welded to the other steel pipe pile 1 through the steel outer ring, and the inner joint pipe is inserted into the outer joint pipe in such a manner that the holes of the inner and outer joint pipes communicate with each other. The end surface of the steel outer ring and the end surface of the outer joint pipe are made to face each other, and the steel cylindrical body is inserted into the holes to joint the inner joint pipe to the outer joint pipe. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mechanical joint for steel pipe piles, and more particularly to a mechanical joint for steel pipe piles that requires no on-site welding and is low in cost.

  Steel pipe piles are widely used in various civil engineering works together with concrete piles, and are often joined at construction sites according to site conditions. Generally, welding is used for joining these piles in the field, but there are problems such as difficulty in ensuring the welding quality, the fact that the welding work is easily influenced by the weather, and the long work time. For this reason, recently, mechanical joints that do not require on-site welding are often used, and are particularly widespread in the field of precast concrete piles. On the other hand, in the steel pipe pile field, its use is currently limited to a limited range.

  The reason for the spread of mechanical joints in the field of precast concrete piles is that steel materials that are several times stronger than concrete can be used as joint materials, and precast concrete piles have steel end plates at both ends. It can be used as a part of. As a result, it is easy to keep the joint cost low. On the other hand, in the steel pipe pile field, although various types of mechanical joints have been proposed or already implemented, the same steel material as the steel pipe body must be used as the joint material. Alternatively, high strength steel is used. In addition, the joint structure is complicated, and many machining costs are high. As a result, the manufacturing cost of the joint becomes high, and the current situation is that the spread is not progressing.

Japanese Patent Application No. 2007-190470 Japanese Patent Application No. 2008-152401

None

  Therefore, the present inventors have proposed, as Japanese Patent Application Nos. 2007-190470 and 2008-152401, mechanical joints of steel pipe piles that have sufficient joint strength and that can be provided at a low cost with a simple structure. Both of them use a pin or a bolt as a steel cylinder connecting the outer joint and the inner joint, but skillfully utilize the characteristics of the external force conditions acting on the foundation pile, making it very simple It has a characteristic that it has sufficient proof stress as a joint of steel pipe piles though it is a simple structure. Moreover, since machining is easy, it is excellent also in terms of economy compared to other types of joints.

  However, compared with the concrete pile joint described above, the manufacturing cost is still high, and it is difficult to say that it is economical to spread widely. There are three reasons for this. The first reason is that the price of steel materials has soared in recent years, so the material cost of the joint material is high. The second reason is that the material of the inner joint material becomes very thick, so an inexpensive electric resistance welded tube can be used. In addition, expensive seamless steel pipes and forged steel pipes must be used, and the third reason is that this is the largest reason, but the amount of machining is large. According to the calculation of the present inventor, in the production of the inner joint material having an L-shaped cross section, the weight machined by a lathe or drilling machine reaches 50 to 60% of the weight of the material (short thick-walled steel pipe), and is half The above steel materials are scraped away. As a result, there is a problem that a high steel material is wasted and the machining cost becomes high.

  Further, when a pin is used as a steel cylinder connecting the inner joint and the outer joint, it is necessary to provide means for preventing the pin from coming out of the insertion hole during construction. In particular, in the case of the rotation penetration method that applies large torques in the forward and reverse rotations during construction, prevention of pull-out is a major issue, and various methods have been proposed to prevent it, but measures to prevent pull-out are an extra cost. In either case, there was a problem in terms of cost in either case.

  In view of the above problems, low-cost yet highly reliable steel pipes that can reduce the manufacturing cost by significantly reducing the material cost and machining cost of the joint, and enabling the steel cylinder to be pulled out at a low cost. It is an object of the present invention to provide a mechanical joint for a pile.

  It has a short cylindrical shape and has approximately the same outer diameter as the pair of steel pipe piles to be joined, and the peripheral wall has a plurality of holes that penetrate the peripheral wall in a radial direction from the axis. An outer joint pipe which is also formed in a short cylindrical shape, has an outer diameter slightly smaller than the inner diameter of the outer joint pipe, and a peripheral wall at a position corresponding to the position where the hole of the outer joint pipe is formed, Inner joint pipe in which holes having the same diameter as the hole of the outer joint pipe are formed radially in a direction perpendicular to the axis; the outer diameter is substantially the same as the outer diameter of the steel pipe pile, and the inner diameter is the inner joint pipe A steel outer ring slightly larger than the outer diameter of the steel; a steel cylinder whose outer diameter is slightly smaller than the hole; and forming a mechanical joint of the steel pipe pile, and the outer joint pipe is pivoted to the end face of one of the steel pipe piles The steel ring is inserted on the outer periphery of one end of the inner joint pipe while welding and fixing so that the centers coincide. The inner joint pipe is connected to the other end of the steel pipe through this steel outer ring by filling the inside of the strip space surrounded by the end face of the steel pipe pile, the end face of the steel outer ring, and the peripheral surface of the inner joint pipe. The inner joint pipe is inserted on the inner diameter side of the outer joint pipe so that the hole of the outer joint pipe communicates with the hole of the inner joint pipe, and the end face of the steel outer ring and the end face of the outer joint pipe The above-mentioned problems have been solved by inserting steel cylinders into these holes and connecting the inner joint pipe and the outer joint pipe.

  As shown in FIG. 2, the upper surface of the inner joint pipe 4 is welded and fixed to the lower end of the upper steel pipe pile 1 through a steel outer ring 9 in a state where the axial centers thereof coincide with each other, and the upper surface of the lower steel pipe pile 2 is The lower end surface of the joint pipe 3 is welded and fixed in a state where the axial centers thereof coincide with each other, the inner joint pipe 4 is inserted into the inner diameter side of the outer joint pipe 3 fixed to the upper surface of the lower steel pipe pile 2, and the steel outer The end face of the ring 9 and the end face of the outer joint pipe 3 are brought into contact with each other, and the positions of the holes 6 and 7 formed in each are aligned. Bonding with the steel pipe pile 1 is performed.

The transmission characteristics of the load in this state will be described with reference to FIGS. 9 to 11. The main load acting on the steel pipe pile is a vertical compressive force, and when this compressive force acts, the lower surface of the steel outer ring 9 and the outer The upper end of the joint pipe 3 abuts, and the compressive force from the pile head is transmitted linearly from the lower end of the upper steel pipe pile 1 to the upper end of the lower steel pipe pile 1 via the weld metal 13 and the steel outer ring 9. For this reason, if the compressive strength of the outer joint pipe 3 is set to be equal to or higher than the compressive strength of the upper steel pipe pile 1, the compressive force is transmitted to the lower steel pipe pile 2 safely and reliably.
On the other hand, when a tensile force acts on the steel pipe pile, the tensile force is transmitted from the lower end of the upper steel pipe pile 1 to the inner joint pipe 4 via the weld metal 13 and then transmitted to the steel cylinder 8 as a shearing force. The shearing force is immediately transmitted to the outer joint pipe 3, converted into a tensile force again, and finally transmitted to the lower steel pipe pile 2 through the welded portion 28. In the transmission of the mutual force between the joint pipes 3 and 4 and the steel cylinder 8 as described above, a bearing stress is generated at the contact portion. However, the bearing stress is not uniformly distributed, and the maximum Since the value is several times the average stress, both joint pipes 3 and 4 tend to yield locally and become plastic, and the force transmission structure between such members via the steel cylinder 8 is cost-effective. However, fortunately, tensile force is generated in steel pipe piles only for a short period of time during an earthquake, and the value is relatively small compared to compressive force. Therefore, even in the structure of the present invention in which the tensile force is transmitted through the steel cylinder 8, the safety is sufficiently maintained.

  Next, the case where a bending moment acts on a steel pipe pile is demonstrated. The transmission of the bending moment in both joint pipes 3 and 4 is performed by two actions. One is the moment transmission by "pushing" generated when the inner joint pipe 4 and the outer joint pipe 3 try to rotate in opposite directions. FIG. 10 schematically shows the state. When a bending moment is applied to both joint pipes 3 and 4, the right side of the upper half and the left side of the lower half are pressed against each other. The distribution of the force with which the inner joint pipe 4 is pushed is represented by an arrow triangle in the figure. The force of these two triangles becomes a couple, resists the moment of the external force, and transmits the moment between the joint pipes 3 and 4. The magnitude of the moment resistance force due to this pressing greatly varies depending on the overlap length L of the joint pipes 3 and 4. The length L is required to be about 1.5 times the diameter of the steel pipe in order to bear all the moments, depending on the thickness of the joint pipes 3 and 4, and as a result, the entire joint pipes 3 and 4 as a whole. The length needs to be about twice the diameter of the steel pipe pile, and the manufacturing cost of both joint pipes 3 and 4 is very high, but in practice the length of both joint pipes 3 and 4 is kept short, It will resist the external force moment together with the moment burden due to the action.

Another moment transmission is performed by the contact between the steel cylinder 8 and the joint pipes 3 and 4. When the joint pipes 3 and 4 are viewed in an annular cross section, a tensile force is generated in the semicircular area and a compressive force is generated in the remaining semicircular area. It is transmitted by the steel cylinder 8 by the same mechanism as the transmission. On the other hand, the compression force generation part is slightly complicated, and is transmitted by the contact between the steel outer ring 9 and the upper end of the outer joint pipe 3 as in the case of the above-described compression force transmission, and is transmitted by the steel cylinder 8 as in the tensile force. There are two ways. In many cases, since not only a bending moment but also a compressive force acts simultaneously as a load, the upper end of the steel outer ring 9 and the outer joint pipe 3 are in contact with each other, and the compressive force is transmitted here. However, when a tensile force is applied simultaneously with bending as an external force, the steel outer ring 9 and the end of the outer joint pipe 3 are not in contact with each other, so that no force is transmitted and the steel cylinder 8 is interposed. The compression force is transmitted.
As described above, the transmission of bending moment is somewhat complicated, but the bending moment that normally acts on steel pipe piles is limited to a short time during an earthquake, and the large bending moment is a limited range near the pile head. Since a large bending moment does not act on both joint pipes 3 and 4, even if a structure in which the bending moment is borne by the steel cylindrical body 8, safety is not practically impaired.
As described above, the mechanical joint for steel pipe piles according to the present invention has a simple structure, but can ensure a sufficient proof strength against an external force acting on the joint.

  Further, the steel outer ring 9 interposed between the upper steel pipe pile 1 and the inner joint pipe 4 is separate from the inner joint pipe 4, and is used when the inner joint pipe 4 is manufactured by machining. In the same manner, a part of the steel material is not wasted and discarded as cutting waste, and it is not necessary to use an expensive thick steel pipe, and the inner joint pipe 4 itself may be an inexpensive steel pipe such as an electric resistance welded steel pipe, The weight of the steel material can be reduced and the amount of cutting can be greatly reduced, the processing cost can be greatly reduced, and valuable metal materials can be effectively used.

The perspective view of Example 1 of the mechanical coupling of the steel pipe pile which concerns on this invention. Similarly, the half cut sectional view. Similarly, arrow AA sectional view taken on the line in FIG. Similarly, the expanded fragmentary sectional view which showed the welding point of an outer joint pipe and a lower steel pipe pile. Similarly, the expanded partial sectional view which showed the connection point when the outer diameter of an inner joint pipe and the inner diameter of an upper steel pipe pile differ. Similarly, the expanded partial sectional view which showed the point for welding and adhering an inner joint pipe and an upper steel pipe pile. Similarly, the perspective view of an inner joint pipe at the time of providing the hole which inserts steel cylinders in two steps. Similarly, the longitudinal cross-sectional view at the time of combining an inner joint pipe and an outer joint pipe with a bottle / nut. Similarly, the longitudinal cross-sectional view which showed the coupling | bonding state of the outer joint pipe and the inner joint pipe in order to demonstrate the transmission characteristic of a load. Similarly, explanatory drawing when a bending moment acts on this mechanical joint. Similarly, the longitudinal cross-sectional view which showed the state which the bending moment acted and the joint location deform | transformed into the "<" shape. Similarly, when a bending moment is applied, an enlarged partial cross-sectional view of an embodiment in which a joint portion is prevented from being deformed into a “<” shape. Similarly, when a bending moment is applied, an enlarged partial cross-sectional view of an embodiment in which a joint portion is prevented from being deformed into a “<” shape. The half-cut longitudinal cross-sectional view of Example 2 of the mechanical coupling of the steel pipe pile which concerns on this invention. Similarly, the expanded partial sectional view of other examples of steel inner rings. Similarly, the expanded partial sectional view of other examples of steel inner rings. Similarly, the longitudinal cross-sectional view of the Example which further strengthened the yield strength to a bending moment. The longitudinal cross-sectional view of Example 3 of the mechanical coupling of the steel pipe pile which concerns on this invention. Similarly, the perspective view of the steel cylinder which is the principal part. Similarly, the expanded sectional view of the projection part of a steel cylinder. Similarly, explanatory drawing which showed the point which inserts steel cylinders in a hole. Similarly, explanatory drawing of the state by which the steel cylinder was inserted in the hole. The fragmentary sectional view which shows the Example by which the hole formed in the inner joint pipe is a blind hole.

  It has a short cylindrical shape and has approximately the same outer diameter as the pair of steel pipe piles to be joined, and the peripheral wall has a plurality of holes that penetrate the peripheral wall in a radial direction from the axis. An outer joint pipe that is also formed in a short cylindrical shape, has an outer diameter slightly smaller than the inner diameter of the outer joint pipe, and a peripheral wall at a position corresponding to the position where the hole of the outer joint pipe is formed, Inner joint pipe in which holes having the same diameter as the hole of the outer joint pipe are formed radially in a direction perpendicular to the axis; the outer diameter is substantially the same as the outer diameter of the steel pipe pile, and the inner diameter is the inner joint pipe A steel outer ring slightly larger than the outer diameter of the steel; a steel cylinder whose outer diameter is slightly smaller than the hole; and the outer joint pipe is welded and fixed so that the axial center of the outer joint pipe coincides with the end face of one of the steel pipe piles At the same time, the steel ring is inserted into the outer periphery near one end of the inner joint pipe, and the end face of the steel pipe pile, steel The inner joint pipe is welded and fixed to the other steel pipe pile via this steel outer ring by filling the inside of the belt-shaped space surrounded by the end face of the outer ring and the peripheral surface of the inner joint pipe with the weld metal, Insert the inner joint pipe on the inner diameter side of the outer joint pipe so that the hole of the outer joint pipe communicates with the hole of the inner joint pipe, and with the end face of the steel outer ring facing the end face of the outer joint pipe, By inserting a steel cylinder into these holes, the inner joint pipe and the outer joint pipe were joined.

  1 is a perspective view of Embodiment 1 of a mechanical joint for steel pipe piles according to the present invention, FIG. 2 is a half-cut longitudinal sectional view thereof, and FIG. 3 is a cross-sectional view taken along line AA in FIG.

  In the figure, 1 is the upper steel pipe pile to be joined, 2 is the lower steel pipe pile, and the mechanical joint of the steel pipe pile according to the present invention is such that the lower end of the upper steel pipe pile 1 and the upper end of the lower steel pipe pile 2 are connected to the outer joint. The pipe 3 and the inner joint pipe 4 are interposed and connected in series.

  The outer joint pipe 3 is a steel pipe having a short cylindrical shape, and has an outer diameter substantially the same as the outer diameter of the lower steel pipe pile 2 to be joined, and its axis coincides with the axis of the lower steel pipe pile 2. In addition, it is firmly fixed to the lower steel pipe pile 2 by welding to the end face of the lower steel pipe pile 2. In the figure, 28 is a weld metal that joins both. In addition, a plurality of holes 6 are formed in the peripheral wall 5 so as to penetrate the peripheral wall 5 in a radial direction in a direction perpendicular to the axis.

  On the other hand, the inner joint pipe 4 is made of a steel tube having a short cylindrical shape like the outer joint pipe 3 and has an outer diameter slightly smaller than the inner diameter of the outer joint pipe 3. Similarly, a plurality of holes 7 are formed at equal intervals radially in the direction perpendicular to the axis, and the holes 6 of the outer joint pipe 3 and the holes 7 of the inner joint pipe 4 are made of steel. By inserting the cylindrical body 8, the outer joint pipe 3 and the inner joint pipe 4 can be coupled. In the embodiment shown in FIG. 2, the hole 7 formed in the inner joint pipe 3 is a through-hole penetrating the peripheral wall, but the inner peripheral surface side is closed as shown in FIG. It may be a blind hole. In this case, the steel cylinder 8 inserted into the hole can be prevented from falling off to the inner peripheral side.

  Reference numeral 9 in the figure denotes a steel outer ring that is interposed when the inner joint pipe 4 is fixed to the upper steel pipe pile 1. The inner diameter is slightly larger than the outer diameter of the inner joint pipe 4, and the outer diameter of the upper steel pipe pile 1 is They have substantially the same outer diameter, and the cross section has an angular shape. Furthermore, 8 in the figure is a steel cylinder having a pin shape whose outer diameter is slightly smaller than the hole 6 and the steel 7, and can be easily manufactured by cutting a long cylindrical steel rod into a short length. I can do it.

  Then, as shown in FIGS. 2 and 6, a steel outer ring 9 is inserted into the outer periphery near one end of the inner joint pipe 4, and the upper steel pipe pile 1 has a lower end surface 10 and a steel outer ring 9 above. The inner joint pipe 4 is fixed to the lower end of the upper steel pipe pile 1 by filling the inside of the strip-shaped space surrounded by the end face 11 and the outer peripheral face 12 of the inner joint pipe 4 with the weld metal 13.

  In the first embodiment, the inner joint pipe 4 is fixed to the upper steel pipe pile 1 and the outer joint pipe 3 is fixed to the lower steel pipe pile 2. The outer joint pipe 3 may be fixed to the lower steel pipe pile 2. Both the outer joint pipe 3 and the inner joint pipe 4 are obtained by cutting a ready-made steel pipe into a short length, which is sufficient as compared with the inner joint pipes in Japanese Patent Application Nos. 2007-190470 and 2008-152401 previously proposed by the applicant. A thin steel pipe is sufficient, and an inexpensive electric resistance welded pipe can also be used.

  In this embodiment, when the outer joint pipe 3 is welded and fixed to the lower steel pipe pile 2, as shown in FIG. 4, the backing ring 14 is brought into contact with the inner peripheral surface side and welded from the outer surface side. However, the backing ring 14 may not be used and welding may be performed from both the inside and outside. Further, as shown in FIG. 4, the lower end surface of the outer joint pipe 3 may be chamfered obliquely to form a bevel welding slope 15 so that the penetration can be made more reliably and the fixing can be ensured. It becomes.

  In addition, although it is preferable that the inner diameter of the upper steel pipe pile 1 and the outer diameter of the inner joint pipe 4 are substantially the same, the outer diameter of the inner joint pipe 4 is actually the upper steel pipe pile 1 of the upper steel pipe pile 1 for reasons of design. Although it may be smaller than the inner diameter, in such a case, a steel filler 16 is interposed between the inner peripheral wall surface of the upper steel pipe pile 1 and the outer peripheral wall of the inner joint pipe 4 as shown in FIG. What is necessary is just to fill in the clearance gap between both and to weld in this state.

In the first embodiment, the upper steel pipe pile 1, the inner joint pipe 4 and the steel outer ring 9 are welded at a time, and the width of the welded portion is appropriately secured, so that the weld metal 13 is interposed. The three can be completely integrated. As a welding method at this time, the upper steel pipe pile 1, the inner joint pipe 4, the three steel column bodies 9, and the steel filler 16 are temporarily welded to each other and placed on a turning roller and rotated at a constant speed. However, means for welding the strip-shaped space surrounded by the three parties in order from the bottom downward is used.
FIG. 6 shows the welding order and the target position / angle of the welding torch at this time. The numbers attached to the arrows in the figure indicate the welding order, and the arrows indicate the target position / angle of the welding torch. In addition, since such multi-layer welding requires a long time, it is desirable to use a welding robot in order to maintain the required welding quality.

  Further, the holes 6 and the holes 7 for connecting the outer joint pipe 3 and the inner joint pipe 4 may be arranged not only in one row but also in two stages. However, when the holes 6 and 7 are arranged in two upper and lower stages as described above, as shown in FIG. 7, the upper and lower stages are respectively arranged in a staggered manner to avoid stress concentration inside the joint pipes 3 and 4. Is desirable.

  Further, in the above embodiment, the outer joint pipe 3 and the inner joint pipe 4 are joined by the steel cylinder 8 having a pin shape. However, as shown in FIG. 17 may be inserted and tightened with a nut 18, and in this case, the outer joint pipe 3 and the inner joint pipe 4 are separated and deformed into a "<" shape when the bending moment is applied. This phenomenon is less likely to occur.

Further, as shown in FIG. 12, an inverted stepped engagement surface 31 is formed on the lower end surface of the steel outer ring 9, and a corresponding stepped engagement surface 32 is formed on the upper end surface of the outer joint pipe 3. By doing so, it is possible to prevent the outer joint pipe 3 and the inner joint pipe 4 from being separated when the engagement surfaces 31 and 32 are engaged when the bending moment is applied, and when the bending moment is applied. It is possible to more effectively suppress the decrease in rigidity.
Further, as shown in FIG. 13, a reverse tapered engagement surface 31 may be formed on the lower end surface of the steel outer ring 9, and a tapered engagement surface 32 may be formed on the upper end surface of the outer joint pipe 3. In this case as well, it is possible to suppress a decrease in rigidity when the bending moment is applied.

  This Example 1 has the structure as described above, and as shown in FIG. 9, the inner joint pipe 4 is aligned with the lower end of the upper steel pipe pile 1 through the steel outer ring 9 in the axial center. The inner diameter of the outer joint pipe 3 is fixed to the upper surface of the lower steel pipe pile 2 by being welded and fixed to the upper surface of the lower steel pipe pile 2 with the lower end face of the outer joint pipe 3 being welded and fixed in a state where the axis is aligned. The inner joint pipe 4 is inserted on the side, the lower end surface of the steel outer ring 9 and the upper end surface of the outer joint pipe 3 are brought into contact with each other, and the positions of the holes 6 and 7 are aligned. And the lower steel pipe pile 2 and the upper steel pipe pile 1 are coupled, and the steel outer ring 9 is interposed between the upper part of the inner joint pipe 4 and the lower end of the upper steel pipe pile 1. In addition, a contact portion with the upper steel pipe pile 1 is formed on the upper portion of the inner joint pipe 4 without separately forming an L-shaped protruding portion on the upper end of the inner joint pipe 4 as in the conventional case. Years, consisting of upper steel pipe pile 1 can be safely reliably transmit the compressive forces under the steel pipe pile 2. In addition, since there is no need for cutting work to form an L-shaped overhang on the upper part of the inner joint pipe 4 as in the conventional case, wasteful waste of high steel material is eliminated and the machining cost is also extremely low. Is possible.

  FIG. 14 is a half cut sectional view of Embodiment 2 of the mechanical joint for steel pipe piles according to the present invention.

  In the figure, 19 is a steel inner ring having an outer diameter slightly smaller than the inner diameter of the lower steel pipe pile 2, and a stepped engagement surface 20 is formed on the upper surface side. The inner peripheral surface near the end surface is welded and fixed via a weld metal 28.

  On the other hand, a reverse step-like engagement surface 21 is formed at the lower end of the inner joint pipe 4 so as to correspond to the engagement surface 20 of the steel inner ring 19. It is made to oppose with a gap. Other parts are the same as those of the first embodiment, and the same reference numerals are given and the description thereof is omitted. Needless to say, the hole 7 formed in the inner joint pipe 3 may be a blind hole as shown in FIG.

  In the second embodiment, when a bending moment acts on the joint portion of both joint pipes 3 and 4 and the joint portion is likely to be deformed into a "<" shape as shown in FIG. The engagement surface 20 of 19 and the engagement surface 21 of the inner joint pipe 4 are engaged to prevent the outer joint pipe 3 and the inner joint pipe 4 from being separated from each other, and the decrease in bending rigidity is suppressed. .

In addition, when a bending test is performed on a steel pipe with a joint and a single steel pipe, a phenomenon that the bending deformation amount of the steel pipe with a joint becomes larger than that of the single steel pipe tends to occur.
FIG. 11 is an exaggerated depiction of the deformation state of the joint subjected to this bending, and this deformation causes a bias pressure to act on the joint location of both joint pipes 3 and 4, as shown in FIG. This occurs because a part of the contact portion is separated. In the second embodiment, as described above, the steel inner ring 19 prevents the root portion of the outer joint pipe 3 and the lower end portion of the inner joint pipe 4 from being separated, thereby suppressing a decrease in bending rigidity. ing.

  In the second embodiment, it is important to provide a slight gap between the engagement surfaces 20 and 21. If this gap is not provided, the mounting position accuracy of the steel outer ring 9 and the steel inner ring 19 is improved. Even if a slight deviation occurs, the steel outer ring 9 and the upper end portion of the outer joint pipe 3 do not come into contact with each other, and the compressive force cannot be transmitted between the upper steel pipe pile 1 and the outer joint pipe 3.

  In addition, as shown in FIG. 15, the welding location 22 of the outer peripheral surface of the steel inner ring 19 joined to the lower end of the outer joint pipe 3 and the upper end of the lower steel pipe pile 2 may be formed on a slope, By carrying out like this, the difference in thickness of each of the outer joint pipe 3 and the lower steel pipe pile 2 can be compensated. Further, the engaging surfaces 20 and 21 are not necessarily stepped, but may be tapered as shown in FIG.

Further, as shown in FIG. 17, an inverted stepped engagement surface 23 is formed at the lower end of the steel pipe outer ring 9, and a stepped engagement surface 24 is formed at the upper end of the outer joint pipe 3 opposed thereto. In such a case, a pair of forces P ₁ and P ₂ that have a couple relationship that restrains the joint portion from being deformed into a “<” shape is generated, resulting in a resistance moment and a bending strength. Is further enhanced.

  FIG. 18 is a longitudinal sectional view of Example 3 of a mechanical joint for steel pipe piles according to the present invention.

  This Example 3 has a short cylindrical shape, has substantially the same outer diameter as the outer diameter of the pair of steel pipe piles 1 and 2 to be joined, and the peripheral wall is radially directed from the axis toward the direction perpendicular to the axis. An outer joint pipe 3 ′ having a plurality of holes 6 penetrating the peripheral wall, which is also in the form of a short cylinder, is formed on the peripheral wall at a position corresponding to the position where the hole 6 of the outer joint pipe 3 ′ is formed. It consists of an inner joint pipe 4 'in which a plurality of holes 7 are formed radially in the direction perpendicular to the center and a steel cylinder 8' in the form of a pin inserted into these holes 6, 7. The main body 26 of the steel cylinder 8 'has an outer diameter slightly smaller than the inner diameter of the holes 6 and 7, and as shown in FIGS. 19 (a) and 19 (b), one protrusion 25 is provided on the outer peripheral surface thereof. Or it is formed by multiple welding. The height and size of the projection 25 are such that the steel cylinder 8 ′ provided with the projection 25 can be driven into the holes 6 and 7 with a hammer 30 or the like. If the height is too high, it will be difficult to drive and both are not preferred. Therefore, after forming this projection 25 on the main body 26 by welding, the excess portion 29 is cut with a grinder as shown in FIG. If adjusted, the projection 25 having an optimum size can be formed. Further, if the inclined surface 27 is formed on the projection 25 in consideration of the driving direction, the driving insertion becomes easy. Further, the inner joint pipe 4 is not limited to the one having the L-shape shown in FIG. 18, but may be one shown in FIGS. 2 and 14, and the outer joint pipe is also shown in FIGS. Things may be used. The hole 7 formed in the inner joint pipe 3 may be a blind hole shown in FIG.

  In the third embodiment, since the projections 25 are formed on the steel cylinder 8 ′, when the hammers 30 and the like are driven into the communicating holes 6 and 7, as shown in FIG. 21, they are shown in FIG. In the same manner, the protrusion 25 and the inner wall surfaces of the holes 6 and 7 with which the protrusions hit are appropriately deformed, and the steel cylinder 8 ′ is firmly fixed to the holes 6 and 7, even during construction that receives a large rotational torque. The steel cylinder 8 'does not come out of the holes 6 and 7, and it is not necessary to provide a separate retaining means at all, and the manufacturing cost and processing cost can be greatly reduced.

  Also, the steel cylinder 8 'can be easily made by cutting a long cylindrical steel rod into a short length, and a material with high material strength can be obtained at a low cost, so it can be procured at a very low cost. . Further, since the projection 25 is formed by welding, the processing cost for that is very low.

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

DESCRIPTION OF SYMBOLS 1 Upper steel pipe pile 2 Lower steel pipe pile 3 Outer joint pipe 4 Inner joint pipe 5 Peripheral wall 6 Hole 7 Hole 8 Steel cylinder 9 Steel outer ring 10 Lower end surface 11 Upper end surface 12 Outer surface 13 Weld metal 14 Backing ring 15 Open Pre-weld slope 16 Steel filler 17 Bolt 18 Nut 19 Steel inner ring 20 Engagement surface 21 Engagement surface 22 Welding location 23 Engagement surface 24 Engagement surface 25 Projection 26 Main body 27 Slope 28 Weld metal 29 Excess portion 30 Hammer 31 engaging surface 32 engaging surface

Claims (3)

  It has a short cylindrical shape and has approximately the same outer diameter as the pair of steel pipe piles to be joined, and the peripheral wall has a plurality of holes that penetrate the peripheral wall in a radial direction from the axis. An outer joint pipe that is also formed in a short cylindrical shape, has an outer diameter slightly smaller than the inner diameter of the outer joint pipe, and a peripheral wall at a position corresponding to the position where the hole of the outer joint pipe is formed, Inner joint pipe in which holes having the same diameter as the hole of the outer joint pipe are formed radially in a direction perpendicular to the axis; the outer diameter is substantially the same as the outer diameter of the steel pipe pile, and the inner diameter is the inner joint pipe A steel outer ring slightly larger than the outer diameter of the steel; a steel cylinder whose outer diameter is slightly smaller than the hole; and the outer joint pipe is welded and fixed so that the axial center of the outer joint pipe coincides with the end face of one of the steel pipe piles At the same time, the steel ring is inserted into the outer periphery near one end of the inner joint pipe, and the end face of the steel pipe pile, steel By filling the inner ring space surrounded by the end face of the outer ring and the peripheral surface of the inner joint pipe with weld metal, the inner joint pipe is welded and fixed to the other steel pipe pile via the steel outer ring. Insert the inner joint pipe on the inner diameter side of the outer joint pipe so that the hole of the joint pipe communicates with the hole of the inner joint pipe, and with the end face of the steel outer ring facing the end face of the outer joint pipe, A mechanical joint for steel pipe piles, wherein an inner joint pipe and an outer joint pipe are joined by inserting a steel cylinder into both holes.   It has a short cylindrical shape and has approximately the same outer diameter as the pair of steel pipe piles to be joined, and the peripheral wall has a plurality of holes that penetrate the peripheral wall in a radial direction from the axis. The outer joint pipe is also formed in a short cylindrical shape, has an outer diameter slightly smaller than the inner diameter of the outer joint pipe, and is scraped off in an inverted stepped shape or an inverted tapered shape on the inner diameter side of one end. Further, the same engagement surface as that of the outer joint pipe is formed radially on the peripheral wall at a position corresponding to the position where the hole of the outer joint pipe is formed. Inner joint pipe with a hole having a diameter; Steel outer ring whose outer diameter is almost the same as the outer diameter of the steel pipe pile and whose inner diameter is slightly larger than the outer diameter of the inner pipe; A small outer diameter, and one end has a stairway so as to correspond to the engagement surface of the inner joint pipe. Or a steel inner ring with a tapered engagement surface; a steel cylinder whose outer diameter is slightly smaller than the hole; and the outer joint pipe is aligned with the end face of one of the steel pipe piles and the axis is aligned The steel outer ring is inserted into the outer periphery near one end of the inner joint pipe and surrounded by the end face of the steel pipe pile, the end face of the steel outer ring, and the inner joint pipe. The inner joint pipe is welded and fixed to the other steel pipe pile via this steel outer ring by filling the inside of the strip-shaped space with weld metal, and the inner joint pipe is inserted into the inner diameter side of the outer joint pipe. The steel inner ring is welded and fixed to the inner diameter side end of the steel pipe pile so that the engagement surface of the inner joint pipe end faces the engagement surface of the steel inner ring with a slight gap. Insert the inner joint pipe on the inner diameter side of the outer joint pipe so that the hole of the joint pipe communicates with the hole of the inner joint pipe. The end face of the outer joint pipe, the end face of the outer joint pipe, the engagement face of the inner joint pipe and the engagement face of the steel inner ring face each other, and a steel cylinder is inserted into these holes, A mechanical joint for steel pipe piles, characterized in that it is connected to an outer joint pipe.   It has a short cylindrical shape and has approximately the same outer diameter as the pair of steel pipe piles to be joined, and the peripheral wall has a plurality of holes that penetrate the peripheral wall in a radial direction from the axis. An outer joint pipe that is also formed in a short cylindrical shape, has an outer diameter slightly smaller than the inner diameter of the outer joint pipe, and a peripheral wall at a position corresponding to the position where the hole of the outer joint pipe is formed, An inner joint pipe in which a hole having the same diameter as the hole of the outer joint pipe is formed radially in a direction perpendicular to the axis; one or more on the peripheral surface of the main body having an outer diameter slightly smaller than the hole A steel cylinder with protrusions formed by welding; and fixing the outer joint pipe to the end face of one steel pipe pile by welding and fixing the inner joint pipe to the other steel pipe pile The inner pipe of the outer joint pipe is fixed so that the hole of the outer joint pipe communicates with the hole of the inner joint pipe. It is characterized in that the hand pipes are inserted, steel cylinders are driven into these holes, and the inner joint pipe and the outer joint pipe are joined in a state where the projections are deformed and pressed against the inner peripheral surfaces of these holes. Mechanical joint for steel pipe piles.

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