JP2019027037A - Foundation structure, pile head structure of steel pipe pile, and construction method of foundation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb and join a pile axis of a steel pipe pile and a column axis of an upper frame column in a horizontal direction, and it is possible to suppress an increase in cost by eliminating the need to change the upper frame column. SOLUTION: The tubular steel pipe 43 is arranged between an upper frame pillar 2 and a steel pipe pile 3 and has a diameter larger than the pile diameter of the steel pipe pile 3, and the diameter is reduced downward from the lower end of the tubular steel pipe 43. A connecting member 4 including an outer steel pipe 41 having a conical steel pipe 44 and a filled concrete 42 filled inside the outer steel pipe 41 is provided, and the tubular steel pipe 43 has a taper that expands in diameter downward. The upper frame pillar 2 is formed and connected to the outer steel pipe 41 via an anchor bolt 22 which is partially fixed to the filled concrete 42, and the connecting member 4 is at least one of the conical steel pipes 44 in the pile head 3A. With the portion inserted, the conical steel pipe 44 provides a basic structure in which the conical steel pipe 44 is welded at the contact point with the pile head 3A. [Selection diagram] Fig. 1

Description

  The present invention relates to a foundation structure, a pile head structure of a steel pipe pile, and a construction method of the foundation structure.

  Conventionally, in a frame foundation, a structure in which a required pile size and number are determined according to the load condition of the frame and these are connected by a reinforced concrete foundation is generally used. This structure has the advantage that the degree of freedom of the material of the pile (steel material, concrete, etc.) is large, and the pile placement error can be absorbed. On the other hand, the excavation range required for foundation construction is large, and it is necessary to apply connecting members to the pile heads in order to connect with foundation concrete. For this reason, there is a problem that the construction period becomes long and the construction cost becomes high.

  In order to solve such a problem, a structure in which one pillar is supported by one steel pipe pile has been proposed. This structure has no concrete foundation, and it is not necessary to connect the pile head and foundation concrete, so the excavation work, formwork, rebar, etc., which were required in the past, can be omitted, and the construction period is greatly shortened. Is possible. In addition, although the cost of the pile is relatively high, since the foundation concrete work is unnecessary, the construction cost can be reduced. However, since the pile diameter of the steel pipe pile depends on the size of the base plate fixed to the upper frame column, if the base plate is larger than the pile diameter determined by the load of the upper frame, the pile diameter Therefore, there is a problem that the cost of pile driving work increases.

  Then, the connection member which consists of a steel pipe which connects between a pillar and a pile is provided, and the structure which transmits the load of a pillar to a steel pipe pile via this connection member is proposed. According to this structure, the pile diameter is not determined by the size of the base plate of the upper frame column, and a more rational pile diameter can be selected. However, in this case, the connecting member needs to embed the column base and the pile head in the connecting member in order to surely transmit stress. As a result, the excavation depth is, for example, a pile diameter or a column size of 2 It is often deeper than conventional frame foundations, such as double the depth. Therefore, when the groundwater level is shallow, it is necessary to perform pumping, and since the length of the connecting member is also long, it is necessary to temporarily fix it during the period until it is filled with concrete. There was a problem.

  On the other hand, Patent Document 1 proposes a structure in which the excavation depth at the time of joining the column and the pile is suppressed and the length of the connecting member is shortened. FIG. 12 shows the structure of Patent Document 1, in which the circular outer diameter of the flat surface portion (base plate 101) is larger than the diameter of the steel pipe pile 3, and the other surface forms a curved surface portion of the conical connecting member 102. The joint jig 100 filled with the concrete 103 is used, the base plate 101 of the joint jig 100 is welded in advance, and the curved surface of the conical connecting member 102 so that the upper frame 2 is at a predetermined angular position. The structure which couple | bonds a part with the upper end part of the steel pipe pile 3 by welding is known.

JP-A-8-4024

However, the conventional structure shown in Patent Document 1 has the following problems.
In other words, steel pipe piles are driven into the ground at the site using a pile driving machine, and construction errors always occur, but as a result, this is a horizontal displacement between the pile axis of the steel pipe pile and the column axis of the upper frame column. In order to correct this, as shown in FIG. 12, the mounting position of the upper frame column 2 on the base plate 101 is corrected or the structure of the base plate 101 is changed in accordance with the construction accuracy of the steel pipe pile. There is a problem that the construction is complicated and the cost is increased.
Moreover, since the space dimension of the connecting member 102 of the steel pipe pile 3 and the upper frame column 2 is small, the connection means between the upper frame column 2 and the connection member 102 is inevitably only the means of the joining jig 100 in the field. When the load on the upper structural column 2 is large, it is necessary to make the base plate 101 and the joining jig 100 have a firm specification, which further increases the cost.
In addition, the filled concrete 103 must be constructed after the upper frame 2 and the base plate 101 are installed. In order to reliably fill the closed space, special concrete with high fluidity or special filling confirmation It was necessary to use a means, and it helped increase the complexity and cost of construction.

  The present invention has been made in view of the above-described problems, and can absorb a horizontal shift between a pile axis of a steel pipe pile and a column axis of an upper structural column, and can be joined. It is not necessary to change the base plate, and it is possible to use various methods for fixing the upper frame pillars. In addition, in the construction of filled concrete, foundations that do not require special materials and quality confirmation means, steel pile piles It aims at providing the construction method of a head structure and a foundation structure.

  In order to achieve the above object, a foundation structure according to the present invention is a foundation structure in which an upper frame column and a pile head of a steel pipe pile placed in the ground are joined, and the upper frame column and A tubular steel pipe disposed between the steel pipe piles and having a diameter larger than the pile diameter of the steel pipe pile, and an outer steel pipe having a conical steel pipe having a diameter reduced downward from a lower end of the tubular steel pipe; A connecting member provided with filled concrete filled in an outer steel pipe, the tubular steel pipe is formed in a taper that expands in a downward direction, and a part of the upper structural column is filled It is connected to the outer steel pipe through an embedding tool fixed to concrete, and the connecting member is in a state in which at least a part of the conical steel pipe is inserted into a pile head of the steel pipe pile. The steel pipe is welded at the contact point with the pile head.

  Moreover, the foundation structure according to the present invention is a foundation structure in which an upper frame column and a pile head of a steel pipe pile placed in the ground are joined, and the upper frame column and the steel pipe pile An outer steel pipe having a cylindrical steel pipe disposed between and having a diameter larger than the pile diameter of the steel pipe pile, and a conical steel pipe having a diameter reduced downward from the lower end of the cylindrical steel pipe, and the inside of the outer steel pipe A connecting member including a filled concrete, and the cylindrical steel pipe is formed in a taper that expands downward, and a lower end portion of the upper frame pillar is embedded in the filled concrete, The connecting member is characterized in that the conical steel pipe is welded at a contact point with the pile head in a state where at least a part of the conical steel pipe is inserted into the pile head of the steel pipe pile. Yes.

  Further, the pile head structure of a steel pipe pile according to the present invention is a pile head structure of a steel pipe pile joined to an upper frame column, the pile head of the steel pipe pile placed in the ground, and the upper frame column And an outer steel pipe having a conical steel pipe whose diameter is reduced downward from a lower end of the cylindrical steel pipe, and a tubular steel pipe having a diameter larger than the pile diameter of the steel pipe pile, A connecting member provided with filled concrete filled in the outer steel pipe, the tubular steel pipe is formed in a taper that expands downward, and the connecting member is a pile of the steel pipe pile. The conical steel pipe is welded at a contact point with the pile head in a state where at least a part of the conical steel pipe is inserted into the head.

  Moreover, the construction method of the foundation structure which concerns on this invention is a construction method of the foundation structure mentioned above, Comprising: The said cone-shaped steel pipe is inserted from the upper side inside the said pile head, The said pile head and the said cone-shaped steel pipe Welding the contact point where the outer steel pipe contacts, placing the upper frame pillar inside the outer steel pipe, and filling the inside of the outer steel pipe with concrete to provide filled concrete. It is said.

In the present invention, a part of the upper frame column or the upper frame column via the embedding tool is embedded in the filled concrete filled inside the cylindrical steel pipe of the connecting member, and the upper frame column is fixed. Will be joined to the connecting member fixed to the pile head of the steel pipe pile.
And in this invention, since the cylindrical steel pipe is formed in the taper so that it may expand toward the downward direction, it can prevent that filling concrete slips out upwards with an upper frame pillar from an outer steel pipe. Moreover, the load of the upper frame column can be reliably transmitted from the outer steel pipe to the steel pipe pile through the filled concrete. That is, the load on the upper frame column is first transmitted to the filled concrete, and this load is transmitted to the cylindrical steel pipe having a tapered surface, and further transmitted from the conical steel pipe to the steel pipe pile. Further, since a separate locking member for preventing the vertical displacement between the filled concrete and the outer steel pipe is not required, the connecting member can be easily formed at low cost.

  Moreover, in this invention, since an upper frame pillar (or embedding tool) can be embed | buried in arbitrary positions in the inner side range (area | region of a filling concrete) of an outer steel pipe, the pile of the steel pipe pile tentatively laid Even when the shaft is displaced in the horizontal direction from the column axis of the upper frame column, the horizontal frame can be absorbed and the upper frame column can be joined to the connecting member at the designed position. That is, even if the pile axis of the steel pipe pile and the column axis of the upper frame column are displaced in the horizontal direction, it can be joined without reducing the joining strength.

Further, in the present invention, the conical steel pipe of the connecting member is brought into contact with the pile head of the steel pipe pile and fixed, so that the size of the connecting member can be changed regardless of the pile diameter of the steel pipe pile. . Therefore, it is possible to respond by changing only the size of the connecting member according to the load and size of the upper frame column embedded in the filled concrete in the outer steel pipe, and select the economical pile diameter of the steel pipe pile It becomes possible to do.
In addition, since the contact between the steel pipe pile and the connecting member is directly brought into contact with and fixed by welding or the like, the excavation depth does not become deep and the joining work becomes easy.

  In the foundation structure according to the present invention, a base plate is provided at a lower end of the upper frame column, and the base plate is in contact with an upper surface of the filled concrete filled in the cylindrical steel pipe. It is good also as connecting to the said outer steel pipe via the insertion tool.

  By setting it as such a structure, the base plate fixed to the lower end of an upper frame pillar can be reliably installed in contact with the concrete surface of the filling concrete located in the upper surface of a connection member.

  Further, the implanter in the foundation structure according to the present invention may be an anchor bolt.

  In this case, by embedding anchor bolts in the filling concrete of the connecting member in advance, the erection work of the upper frame and the foundation work can be separated, and efficient construction becomes possible. .

Moreover, it is preferable that the basic structure which concerns on this invention is provided with the ring member extended in the circumferential direction in the outer surface of the said cylindrical steel pipe.
In the pile head structure of a steel pipe pile according to the present invention, a ring member extending in the circumferential direction is preferably provided on the outer surface of the cylindrical steel pipe.

  With such a configuration, when the load of the upper frame column is transmitted to the cylindrical steel pipe of the outer steel pipe through the filling concrete, the ring member extends along the circumferential direction on the outer surface of the cylindrical steel pipe Thus, the tubular steel pipe can be prevented from spreading outward in the radial direction around the pipe axis. Therefore, the shape of the outer steel pipe can be maintained, and the adhesion state of the filled concrete to the outer steel pipe can be favorably maintained.

According to the foundation structure of the present invention, the pile head structure of the steel pipe pile, and the construction method of the foundation structure, it is possible to absorb the horizontal displacement between the pile axis of the steel pipe pile and the column axis of the upper frame column and to join them. This eliminates the need to change the upper frame column and base plate.
Moreover, in this invention, it is possible to use various fixing methods of an upper frame pillar, and also there exists an advantage which does not need to take a special material and a quality confirmation means in construction of filling concrete.

It is a longitudinal cross-sectional view which shows the structure of the basic structure by the 1st Embodiment of this invention. It is the top view which looked at the basic structure shown in FIG. 1 from upper direction. It is the partially broken perspective view which shows the structure of the pile head structure which joined the connection member to the steel pipe pile among the foundation structures shown in FIG. (A)-(c) is a figure which shows the construction procedure of foundation structure. (A), (b) is a figure which shows the construction procedure of the foundation structure following FIG.4 (c). It is a longitudinal cross-sectional view which shows the foundation structure joined in the state which the column axis of the upper frame column shifted | deviated to the horizontal direction with respect to the pile axis of a steel pipe pile. It is a longitudinal cross-sectional view which shows the structure of the foundation structure by 2nd Embodiment. It is a longitudinal cross-sectional view which shows the structure of the connection member by a 1st modification. (A), (b) is a figure which shows the construction procedure of the foundation structure by a 2nd modification. It is a longitudinal cross-sectional view which shows the structure of the basic structure by a 3rd modification. It is a longitudinal cross-sectional view which shows the structure of the basic structure by a 4th modification. It is a longitudinal cross-sectional view which shows the structure of the conventional foundation structure.

  Hereinafter, the foundation structure by the embodiment of the present invention, the pile head structure of a steel pipe pile, and the construction method of a foundation structure are explained based on a drawing.

(First embodiment)
As shown in FIG. 1, the foundation structure 1 according to this embodiment includes an upper frame column 2 of an upper frame and a pile head 3 </ b> A of a steel pipe pile 3 placed in the ground via a connecting member 4. It is a joined structure. In the present embodiment, the entire pile head 3A is located in the ground, and the upper part of the connecting member 4 is disposed in a state exposed to the ground.

  The upper frame column 2 is made of an H-shaped steel material, and is connected to the steel pipe pile 3 so that the column axis O1 is coaxial with the pile axis O2 of the steel pipe pile 3 and the pipe axis O3 of the connecting member 4. A base plate 21 having a plate surface orthogonal to the direction of the column axis O1 is welded to the lower end of the upper frame column 2 (see FIG. 2). The base plate 21 is arranged in a state in which the base plate 21 is in contact with an upper surface 42a of a filling concrete 42 (described later) of the connecting member 4 by an anchor bolt 22 (embedding tool). It is joined to.

  The anchor bolt 22 is inserted from above into a through hole 21 a provided in the base plate 21, and a portion protruding to the lower surface side of the base plate 21 is fixed to the filling concrete 42. The protruding length of the anchor bolt 22 from the lower surface of the base plate 21 at this time is a length that does not contact the inner surface of the connecting member 4 in a state where the base plate 21 is disposed at a predetermined height, and is filled concrete. The length is set so as to ensure a sufficient fixing strength with respect to 42.

  The steel pipe pile 3 is a cylindrical steel pipe, and is placed in the ground ahead of the upper frame column 2 with the pile axis O2 in the vertical direction.

As shown in FIGS. 1 and 3, the connecting member 4 includes an outer steel pipe 41 and filled concrete 42 filled in the outer steel pipe 41. The connecting member 4 is fixed to the steel pipe pile 3 so that the pipe axis O3 coincides with the pile axis O2 of the steel pipe pile 3.
The outer steel pipe 41 is arranged between the upper frame column 2 and the steel pipe pile 3, and has a cylindrical steel pipe 43 having a larger diameter (reference numeral D <b> 2) than the pile diameter D <b> 1 of the steel pipe pile 3, and downward from the lower end of the cylindrical steel pipe 43. A conical steel pipe 44 having a reduced diameter.

  The cylindrical steel pipe 43 has a constant thickness and is formed in a taper that gradually increases in diameter from the upper end toward the lower end. The inclination angle θ of the taper of the cylindrical steel pipe 43 (inclination angle with respect to the direction of the pipe axis O3) can be obtained by calculation from the applied external force. In addition, when the inclination | tilt angle (theta) of this taper becomes large, since construction of concrete will become difficult, it is preferable to set to the minimum required angle in consideration of workability.

The conical steel pipe 44 has an opening 44a at the reduced diameter. The opening 44a may be closed. The inclination angle of the conical steel pipe 44 (the angle of the inclined surface from the upper end to the lower end) can be set as appropriate.
In the connecting member 4, the conical steel pipe 44 is welded at a contact point (welding portion W) with the pile head 3 </ b> A in a state where the substantially lower half portion of the conical steel pipe 44 is inserted inside the pile head 3 </ b> A. .

Next, the construction method of the foundation structure 1 mentioned above is demonstrated in detail based on drawing.
First, as shown to Fig.4 (a)-(c), the connection member 4 is joined to the pile head 3A of the steel pipe pile 3 laid previously. Specifically, as shown in FIG. 4A, the outer steel pipe 41 of the connecting member 4 is inserted from above into the pile head 3A so that the pipe axis O3 coincides with the pile axis O2. As shown in FIG. 4B, the contact portion where the upper end portion 3a of the pile head 3A and the outer steel pipe 41 are contacted is welded from the outside of the pile head 3A over the entire circumference, and the pile head is welded by the welded portion W. 3A and the connecting member 4 are joined.

  Further, a plurality of boxing members 46 (the same number as the anchor bolts 22) for securing the anchor placing region 22A necessary for placing the above-described anchor bolts 22 are arranged inside the outer steel pipe 41. The box-opening member 46 is a mold that is removed after the filling concrete 42 is hardened, has a bottomed cylindrical shape, and is temporarily fixed with the open end 46 a aligned with the upper end 41 a of the outer steel pipe 41. . The installation position of the box removing member 46 at this time is adjusted in accordance with the position of the upper frame column 2. That is, the position of the anchor bolt 22 fixed to the base plate 21 fixed to the upper frame column 2 is confirmed, and the anchor bolt 22 is positioned and temporarily fixed at a position where it can be inserted into the concave portion of the box removing member 46.

Then, as shown in FIG.4 (c), the concrete C is filled inside the outer steel pipe 41, and the filling concrete 42 is formed. At this time, it is preferable to close the opening 44a of the conical steel pipe 44 by an appropriate means. And the anchor placement area | region 22A is formed by removing the box extraction member 46 shown in FIG.4 (b) at the appropriate timing when the filling concrete 42 hardened | cured.
In this manner, the joining of the connecting member 4 to the pile head 3A is completed in a state where the outer steel pipe 41 joined to the pile head 3A is filled with the filled concrete 42.

Next, as shown in FIGS. 5A and 5B, the upper frame column 2 is joined to the connecting member 4. Specifically, as shown in FIG. 5A, the anchor bolt 22 is disposed in the anchor placement region 22 </ b> A in a state of protruding upward from the connecting member 4. In addition, in order to adjust the level of the ground contact surface of the upper structural column 2, if a procedure for constructing a level adjusting grout or the like on the upper surface of the filling concrete 42 is used, the connecting member 4 and the filling concrete 42 which are the previous steps are used. In construction, the effort of leveling in the height direction is reduced, and more efficient construction is possible.
Thereafter, as shown in FIG. 5B, the anchor placement region 22 </ b> A is filled with the mortar material 47 and the anchor bolt 22 is fixed to the mortar material 47. Thereafter, the anchor frame 22 is inserted into the through hole 21a of the base plate 21 fixed to the upper frame column 2 and tightened with the nut 23, whereby the upper frame column 2 is fixed to the connecting member 4 via the anchor bolt 22. Construction of the foundation structure 1 is completed.

  According to the foundation structure described above, the pile head structure of the steel pipe pile, and the construction method of the foundation structure, as shown in FIG. 1, in the filling concrete 42 filled inside the cylindrical steel pipe 43 of the connecting member 4, Since the upper frame column 2 via the anchor bolts 22 is buried and brought into a fixed state, the upper frame column 2 is joined to the connecting member 4 fixed to the pile head 3A of the steel pipe pile 3.

And in this Embodiment, since the cylindrical steel pipe 43 is formed in the taper so that it may expand toward the downward direction, the filling concrete 42 is pulled out upward with the upper frame pillar 2 from the outer steel pipe 41. Can be prevented. Moreover, the load of the upper frame column 2 can be reliably transmitted from the outer steel pipe 41 to the steel pipe pile 3 through the filling concrete 42. That is, the load of the upper frame column 2 is first transmitted to the filling concrete 42, and this load is transmitted to the cylindrical steel pipe 43 having a tapered surface, and further transmitted from the conical steel pipe 44 to the steel pipe pile 3.
Further, since a separate locking member for preventing the vertical displacement between the filled concrete 42 and the outer steel pipe 41 is not required, the connecting member 4 can be easily formed at low cost.
In addition, in the present embodiment, since the tubular steel pipe 43 is tapered, the stress acting on the outer steel pipe 41 is reduced, the weight of the tapered tubular steel pipe 43 can be kept small, and the member cost is reduced. It becomes possible to reduce.

  Further, in the present embodiment, as shown in FIG. 6, the anchor bolt 22 of the upper frame column 2 can be embedded at an arbitrary position in the inner range of the outer steel pipe 41 (region of the filled concrete 42). Even if the pile axis O2 of the steel pipe pile 3 that has been laid is displaced in the horizontal direction from the column axis O1 of the upper frame column 2, the upper frame column 2 is designed by absorbing the horizontal displacement. It can be joined to the connecting member 4 at the street position. That is, even if the pile axis O2 of the steel pipe pile 3 and the column axis O1 of the upper frame column 2 are deviated in the horizontal direction, they can be joined without reducing the joining strength.

  Furthermore, in this Embodiment, since the conical steel pipe 44 of the connection member 4 can be contact | abutted and fixed to the pile head 3A of the steel pipe pile 3 irrespective of the magnitude | size of the connection member 4, the steel pipe pile 3 Regardless of the pile diameter, the size of the connecting member 4 can be changed. Therefore, it is only necessary to change the size of the connecting member 4 according to the size of the upper frame column 2 embedded in the filled concrete 42 in the outer steel pipe 41, and the economical pile diameter of the steel pipe pile 3 is selected. It becomes possible.

Furthermore, since the conical steel pipe 44 can be brought into close contact with the steel pipe pile 3 having any pile diameter, there is an advantage that a rational steel pipe pile 3 can be selected.
Further, since the contact point between the steel pipe pile 3 and the connecting member 4 is directly contacted and fixed by welding or the like, the excavation depth does not become deep and the joining operation is facilitated.

  Moreover, in this Embodiment, the base plate 21 fixed to the lower end of the upper frame pillar 2 can be reliably installed in contact with the concrete surface of the filling concrete 42 located on the upper surface of the connecting member 4.

  In the present embodiment, the anchor bolt 22 is embedded in the filled concrete 42 of the connecting member 4 in advance, so that the erection work of the upper frame and the foundation work can be separated, which is efficient. Construction is possible.

  Further, in the case of the present embodiment, as shown in FIGS. 4A to 4C, before filling the filled concrete 42, the box is removed at a position where the anchor bolt 22 inside the outer steel pipe 41 is placed. After the member 46 is disposed, the filling concrete 42 is filled, and after the filling concrete 42 is hardened, the box removing member 46 is removed, so that a space larger than the anchor bolt 22 is formed inside the filling concrete 42 of the connecting member 4. An anchor placement region 22A can be provided. Therefore, it is not necessary to position the anchor bolt 22 with high precision when building the foundation, and the work efficiency can be improved.

  As described above, in the foundation structure according to this embodiment, the pile head structure of the steel pipe pile, and the construction method of the foundation structure, the horizontal shift between the column axis O1 of the upper frame column 2 and the pile axis O2 of the steel pipe pile 3 is performed. It becomes possible to absorb and join, and it is not necessary to change the superstructure, thereby suppressing an increase in cost.

  Next, other embodiments according to the foundation structure of the present invention, the pile head structure of steel pipe piles, and the construction method of the foundation structure will be described based on the accompanying drawings, but the same as the above-described first embodiment or The same members and portions are denoted by the same reference numerals, and the description thereof is omitted. A configuration different from the first embodiment will be described.

(Second Embodiment)
As shown in FIG. 7, the foundation structure 1 </ b> A according to the second embodiment is embedded in the filling concrete 42 in which the lower end 2 a of the upper frame 2 is directly filled in the outer steel pipe 41 of the connecting member 4. It has been configured. In this case, after placing the lower end 2a of the upper frame column 2 directly in the outer steel pipe 41 of the connecting member 4, the outer steel pipe 41 is filled with the filled concrete 42 and hardened.

In the second embodiment, since the embedding tool composed of the anchor bolt 22 (see FIG. 1) as in the first embodiment is not embedded in the filling concrete 42, the base plate 21 and the embedding tool are not used. It can be set as the simple structure which abbreviate | omitted.
In addition, in 2nd Embodiment, the structure embed | buried in the filling concrete 42 in the state which fixed the base plate 21 to the lower end of the upper frame pillar 2 may be sufficient.

(First modification)
The basic structure 1B according to the first modification shown in FIG. 8 has a plurality of stages (here, three stages) extending on the outer surface 43a of the tubular steel pipe 43 over the entire circumference in the circumferential direction centering on the pipe axis O3. The ring member 45 is provided in a state of being fixed by, for example, welding with a gap in the direction of the tube axis O3. Each ring member 45 is made of flat steel in the present embodiment.

  In the first modified example, when the load of the upper frame column 2 is transmitted to the cylindrical steel pipe 43 of the outer steel pipe 41 through the filling concrete 42, it extends along the circumferential direction on the outer surface 43 a of the cylindrical steel pipe 43. Due to the ring member 45, the tubular steel pipe 43 can be prevented from spreading outward in the radial direction around the pipe axis O3. Therefore, the shape of the outer steel pipe 41 can be maintained, and the adhesion state of the filled concrete 42 to the outer steel pipe 41 can be maintained well.

(Second modification)
In the above-described first embodiment, the box opening member 46 for securing the anchor placement region 22A for placing the anchor bolt 22 is arranged as a mold when the foundation structure 1 is constructed. It is also possible to omit the boxing member 46 for construction.
That is, in the construction method of the foundation structure 1 according to the second modification shown in FIG. 9A, the anchor bolt 22 is temporarily fixed at a predetermined position inside the outer steel pipe 41 before the filling concrete 42 is filled in the connecting member 4. After that, the filled concrete 42 is filled. As shown in FIG. 9B, after the filling concrete 42 is hardened, the base plate 21 fixed to the upper frame column 2 is fixed to the anchor bolts 22 fixed to the filling concrete 42.
Also in this case, since the anchor bolt 22 of the upper frame pillar 2 can be embedded at an arbitrary position in the inner area of the outer steel pipe 41 (filled concrete area), the pile axis O2 of the steel pipe pile 3 is connected to the upper frame pillar 2. Even when it is displaced in the horizontal direction from the column axis O1, the upper frame column 2 can be joined to the connecting member 4 at the designed position by absorbing the horizontal displacement.

Further, as another form in which the above-described boxing member 46 is omitted, for example, a cylindrical thin steel plate (so-called winding pipe) whose surface is ribbed is embedded in the filling concrete of the connecting member without being demolded. It is of course possible to adopt a general structure that is used as it is as a hole for an anchor bolt.
Alternatively, the boxing may not be formed in advance, and the filled concrete may be cast without any work, and after the concrete has hardened, a hole (boxing) may be provided by core boring.

(Third Modification)
The basic structure 1C according to the third modification shown in FIG. 10 is not limited to the anchor bolt 22 as described above as an embedding tool, and a plurality of reinforcing bars 24 are suspended from the lower surface of the base plate 21. It is set as the structure set.
The base structure 1 </ b> C is arranged such that the base plate 21 is positioned on the upper surface 42 a of the filling concrete 42, and at this time, a plurality of reinforcing bars 24 are embedded in the filling concrete 42 inside the outer steel pipe 41 of the connecting member 4. . And after the connection member 4 is joined to the steel pipe pile 3 with the base plate 21, the base structure 1C is constructed by fixing the lower end of the upper frame column 2 on the base plate 21 by welding.

(Fourth modification)
As shown in FIG. 11, the foundation structure 1D according to the fourth modification is the base plate via the height adjusting grout 26 on the filling concrete 42 of the connecting member 4 in the first embodiment described above. 21 is arranged. In this case, the grout portion 26 made of mortar is placed on the upper surface 42 a of the filled concrete 42 that is placed together with the anchor bolts 22. At this time, after adjusting the height of the grout portion 26 so as to correspond to the lower end position of the upper frame column 2, the base plate 21 is installed and the upper frame column 2 is built on the base plate 21. The
By providing the grout part 26 in this manner, the accuracy (particularly the height accuracy) of the ground contact surface of the upper frame column 2 can be ensured more reliably.

  As mentioned above, although the embodiment of the foundation structure by this invention, the pile head structure of a steel pipe pile, and the construction method of a foundation structure was described, this invention is not limited to said embodiment, and deviates from the meaning. It is possible to change appropriately within the range not to be.

  For example, in the basic structure 1B according to the first modification described above, the three-stage ring member 45 is provided on the outer surface 43a of the tubular steel pipe 43, but the cross-sectional shape, position, quantity, etc. of the ring member 45 are configured. There is no limit. In the first modification, flat steel is adopted as the ring member 45, but it may be a member such as a steel bar.

  Further, the configuration of the diameter, height, thickness and the like of the cylindrical steel pipe 43 and the conical steel pipe 44 of the connecting member 4 should be appropriately set according to conditions such as the shape of the upper frame column 2 and the load of the upper structure. Can do.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D Foundation structure 2 Upper frame pillar 3 Steel pipe pile 3A Pile head 4 Connecting member 21 Base plate 22 Anchor bolt (embedding tool)
22A Anchor placement area 41 Outer steel pipe 42 Filled concrete 43 Cylindrical steel pipe 43a Outer surface 44 Conical steel pipe 45 Ring member 46 Unboxing member O1 Column axis O2 Pile axis O3 Pipe axis

Claims (8)

A foundation structure in which an upper frame column and a pile head of a steel pipe pile placed in the ground are joined,
A tubular steel pipe disposed between the upper frame column and the steel pipe pile and having a diameter larger than the pile diameter of the steel pipe pile, and a conical steel pipe having a diameter reduced downward from a lower end of the cylindrical steel pipe An outer steel pipe,
Filled concrete filled inside the outer steel pipe;
A connecting member is provided,
The cylindrical steel pipe is formed in a taper that expands downward,
The upper frame column is connected to the outer steel pipe through an embedding part of which is fixed to the filled concrete,
The connecting member is characterized in that the conical steel pipe is welded at a contact point with the pile head in a state where at least a part of the conical steel pipe is inserted into the pile head of the steel pipe pile. Foundation structure to do. A base plate is provided at the lower end of the upper frame pillar,
The said base plate is connected to the said outer steel pipe through the said embedding tool in the state contact | abutted to the upper surface of the said filling concrete with which the said cylindrical steel pipe was filled. Foundation structure.   The foundation structure according to claim 1, wherein the implanter is an anchor bolt. A foundation structure in which an upper frame column and a pile head of a steel pipe pile placed in the ground are joined,
A tubular steel pipe disposed between the upper frame column and the steel pipe pile and having a diameter larger than the pile diameter of the steel pipe pile, and a conical steel pipe having a diameter reduced downward from a lower end of the cylindrical steel pipe An outer steel pipe,
Filled concrete filled inside the outer steel pipe;
A connecting member is provided,
The cylindrical steel pipe is formed in a taper that expands downward,
The lower end portion of the upper frame pillar is embedded in the filled concrete,
The connecting member is characterized in that the conical steel pipe is welded at a contact point with the pile head in a state where at least a part of the conical steel pipe is inserted into the pile head of the steel pipe pile. Foundation structure to do.   The foundation structure according to any one of claims 1 to 4, wherein a ring member extending in a circumferential direction is provided on an outer surface of the cylindrical steel pipe. A pile head structure of steel pipe piles joined to the upper frame column,
A pile head of a steel pipe pile placed in the ground,
A tubular steel pipe disposed between the upper frame column and the steel pipe pile and having a diameter larger than the pile diameter of the steel pipe pile, and a conical steel pipe having a diameter reduced downward from a lower end of the cylindrical steel pipe An outer steel pipe,
Filled concrete filled inside the outer steel pipe;
A connecting member is provided,
The cylindrical steel pipe is formed in a taper that expands downward,
The connecting member is characterized in that the conical steel pipe is welded at a contact point with the pile head in a state where at least a part of the conical steel pipe is inserted into the pile head of the steel pipe pile. Pile head structure of steel pipe pile.   The pile head structure of a steel pipe pile according to claim 6, wherein a ring member extending in a circumferential direction is provided on an outer surface of the cylindrical steel pipe. It is a construction method of the foundation structure according to any one of claims 1 to 5,
Inserting the conical steel pipe from above into the inside of the pile head, and welding the contact point where the pile head and the conical steel pipe abut; and
Arranging the upper frame pillar inside the outer steel pipe;
A step of filling the outer steel pipe with concrete to provide the filled concrete;
A construction method of a foundation structure characterized by comprising:

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