JP2017008543A - Foundation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve labor saving in foundation work by reducing reinforcement work for a footing and dispensing with a temporary steel frame for erecting a steel-frame foundation beam.SOLUTION: A foundation structure 10 includes: a pile 14 which is provided in ground G; a steel pipe 22 which surrounds a pile head 14A of the pile 14; a steel foundation beam 18 which is installed on the steel pipe 22, to which a column 16 erected above the pile head 14A is joined, and which is welded to the steel pile 22; and infilled concrete 24 which is infilled into the steel pipe 22 and which forms a footing 20 for supporting the column 16.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a foundation structure.

  A foundation structure is known in which a foundation beam jointed steel frame and a steel foundation beam (steel foundation beam) are installed in a steel formwork and concrete is filled in the steel formwork to form a footing (for example, , See Patent Document 1).

JP 2002-220842 A

  However, in the foundation structure disclosed in Patent Document 1, for example, there is a possibility that a reinforcing steel construction for footing and a temporary steel frame for constructing a steel foundation beam are required.

  In view of the above facts, the present invention aims to reduce labor in the foundation work by reducing the reinforcement work of the footing and further eliminating the need for a temporary steel frame for constructing the steel foundation beam. To do.

  The foundation structure according to claim 1 is a structure in which a pile provided on the ground, a steel pipe surrounding the pile head of the pile, a column installed on the steel pipe, and a column standing above the pile head are joined. A steel foundation beam to be welded to the steel pipe, and filled concrete that fills the steel pipe and forms a footing that supports the column.

  According to the foundation structure concerning Claim 1, a pile is provided in the ground. The pile head is surrounded by a steel pipe. A steel foundation beam is installed on the steel pipe. The steel foundation beam is welded to a steel pipe while a column standing above the pile head is joined. By filling the steel pipe with filled concrete, a footing that supports the column is formed. That is, the steel pipe functions as a buried form for footing. Accordingly, it is not necessary to temporarily install and remove the footing formwork.

  Moreover, a CFT (Concrete Filled Steel Tube) -like footing is formed by filling the steel pipe with filled concrete. In this case, the steel pipe resists the tensile force and bending acting on the footing. Furthermore, in the CFT-like footing, a constraining effect (confined effect) of the filled concrete by the steel pipe can be obtained. Therefore, reinforcing bars and the like arranged in the filled concrete can be reduced or eliminated. Therefore, it is possible to reduce the reinforcement work for the footing.

  Further, by using a steel pipe as a temporary steel frame (base) for constructing the steel foundation beam, it is not necessary to temporarily install and remove the temporary steel frame for constructing the steel foundation beam.

  As described above, in the present invention, it is possible to reduce labor in the foundation work by reducing the reinforcing work of the footing and further eliminating the need for a temporary steel frame for constructing the steel foundation beam.

  Further, the steel foundation beam is welded to the steel pipe. Thereby, when filling the steel pipe with the filled concrete, the displacement of the steel foundation beam with respect to the steel pipe is suppressed. Therefore, the workability is improved.

  The foundation structure according to claim 2 is the foundation structure according to claim 1, wherein at least one of the steel pipe, the column, and the steel foundation beam has a shear force transmission mechanism embedded in the filled concrete. Provided.

  According to the foundation structure according to claim 2, the shear force transmission mechanism is provided in at least one of the steel pipe, the column and the steel foundation beam. By burying this shearing force transmission mechanism in the filled concrete, the shearing force is transmitted between at least one of the steel pipe, the column and the steel foundation beam and the filled concrete. Further, the shearing force transmitted to the filling concrete is transmitted to the pile by pile head friction and horizontal engagement (support pressure) between the pile head and the filling concrete. Therefore, the seismic performance is improved.

  The foundation structure according to claim 3 is the foundation structure according to claim 1 or 2, wherein the pile head is provided with a drawing resistance mechanism that extends upward and is embedded in the filled concrete.

  According to the foundation structure according to the third aspect, the pulling resistance mechanism extending upward from the pile head is embedded in the filled concrete. Thereby, for example, when an extraction force is transmitted from the pillar to the filled concrete during an earthquake, the extraction force is transmitted to the pile head via the extraction resistance mechanism. Therefore, since the lifting of the column is suppressed, the seismic performance is improved.

  As described above, according to the foundation structure according to the present invention, it is possible to reduce the manpower saving in the foundation work by reducing the reinforcement work of the footing and further eliminating the need for a temporary steel frame for constructing the steel foundation beam. Can be planned.

It is a longitudinal section showing the foundation to which the foundation structure concerning a 1st embodiment of the present invention was applied. FIG. 2 is a sectional view taken along line 2-2 of FIG. (A) And (B) is a longitudinal cross-sectional view explaining the construction method of the foundation shown by FIG. It is a longitudinal section showing the foundation to which the foundation structure concerning a 2nd embodiment of the present invention was applied. FIG. 5 is a sectional view taken along line 5-5 of FIG. It is a longitudinal section showing the foundation to which the foundation structure concerning a 3rd embodiment of the present invention was applied. It is the disassembled side view which decomposed | disassembled the column foundation beam joint member and steel pipe shown by FIG.

  Hereinafter, a basic structure according to an embodiment of the present invention will be described with reference to the drawings.

  First, the first embodiment will be described.

  FIG. 1 shows a foundation 12 to which a foundation structure 10 according to the present embodiment is applied. The foundation structure 10 includes a pile 14, a footing 20, a column (steel column) 16, and a steel foundation beam 18.

  The pile 14 is embedded in the ground G with its pile head 14A protruding upward from the ground G. The pile 14 is, for example, a steel pile (steel pipe pile), a concrete pile, or a synthetic pile. Moreover, the pile 14 may be a ready-made pile or an on-site pile. Furthermore, the pile 14 may be a support pile or a friction pile.

  A pile head 14 </ b> A of the pile 14 is embedded under the footing 20. The footing (foundation footing) 20 has a steel pipe 22 surrounding the pile head 14A of the pile 14 and a filled concrete 24 filled in the steel pipe 22, and is formed in a CFT shape. As shown in FIG. 2, the steel pipe 22 is a circular steel pipe having a diameter larger than that of the pile head 14A. The steel pipe 22 may be formed of a square steel pipe.

  As shown in FIG. 1, the steel pipe 22 is disposed with the vertical direction as an axial direction, and the pile head 14 </ b> A is inserted into the steel pipe 22. 26 is installed. In this state, the pile head 14 </ b> A is buried under the filled concrete 24 by filling the steel pipe 22 with the filled concrete 24. That is, the steel pipe 22 functions as an embedded formwork (steel formwork) of the footing 20. Moreover, the steel pipe 22 functions also as a temporary steel frame for constructing the column foundation beam joint member 30 mentioned later.

  In addition, in FIG. 1, the steel pipe 22 is installed on the discarding container 26 through the adjustment stand 28 for height adjustment. The adjusting table 28 and the above-described discarding container 26 can be omitted as appropriate. Moreover, it is desirable that the steel pipe 22 be arranged coaxially with the pile head 14A. Furthermore, reinforcing bars (reinforcing bars, etc.) may be appropriately arranged in the filled concrete 24.

  A column foundation beam joint member 30 that joins the column 16 and the steel foundation beam 18 is installed on the steel pipe 22. The column foundation beam joint member 30 includes a column bracket 32 and a plurality of foundation beam brackets 40. In this embodiment, the steel pipe 22 is integrated with the column foundation beam joint member 30 in advance by welding.

  The column bracket 32 is formed of, for example, a square steel pipe and forms a column base portion of the column 16. For example, a column main body (not shown) formed of a square steel pipe similar to the column bracket 32 is joined to the upper end portion (not shown) of the column bracket 32. The column 16 is formed by the column bracket 32 and the column main body. The pillar bracket 32 and the pillar main body are filled with concrete 34. That is, the pillar 16 of this embodiment is made of concrete filled steel pipe (CFT). In the present embodiment, the column 16 does not bear the pulling force F or the pulling force F is small enough to be ignored in the structural design.

  The lower part of the column bracket 32 is a foundation beam joint 32S to which the steel foundation beam 18 is joined. The base beam joint portion 32S is provided with a pair of upper and lower diaphragms 36U and 36L. The pair of upper and lower diaphragms 36U and 36L are, for example, through diaphragms formed of steel plates, and are arranged to face each other in the vertical direction.

  Of the pair of upper and lower diaphragms 36U and 36L, the lower diaphragm 36L is joined to the lower end of the column bracket 32 by welding or the like, and closes the lower end side opening of the column bracket 32. A plurality of studs 38 serving as shearing force transmission mechanisms are joined to the lower surface of the diaphragm 36L.

  The plurality of studs 38 project downward from the lower surface of the lower diaphragm 36 </ b> L, are disposed inside the steel pipe 22, and are embedded in the filled concrete 24. A shearing force is transmitted between the column foundation beam joint member 30 and the filled concrete 24 through these studs 38. The lower diaphragm 36L can also be regarded as the base plate of the column bracket 32 (column 16). That is, the stud 38 as a shearing force transmission mechanism is provided on the column 16.

  On the other hand, of the pair of upper and lower diaphragms 36U and 36L, a filling hole 39 penetrating the central portion in the thickness direction is formed in the central portion of the upper diaphragm 36U. The concrete beam filling portion 32S is filled with concrete 34 through the filling hole 39. Note that the pair of upper and lower diaphragms 36U and 36L is not limited to a through diaphragm, and may be an inner diaphragm or an outer diaphragm. Further, when the concrete beam 34 is not filled with the concrete 34, the filling hole 39 is unnecessary.

  As shown in FIG. 2, a plurality of (four in this embodiment) foundation beam brackets 40 are arranged in four directions of the foundation beam joint portion 32 </ b> S. As shown in FIG. 3A, each foundation beam bracket 40 is formed of H-shaped steel, and a web portion that connects a pair of upper and lower flange portions 40U and 40L and a pair of upper and lower flange portions 40U and 40L. 40W. Further, reinforcing ribs 42 extending in the vertical direction are provided on the surface of the web portion 40 </ b> W so as to be continuous with the steel pipe 22. The reinforcing ribs 42 can be omitted as appropriate.

  One end of the foundation beam bracket 40 is joined to the foundation beam joint 32S. Specifically, one end portion of the foundation beam bracket 40 is joined by welding or the like in a state where the pair of upper and lower flange portions 40U and 40L are in contact with the pair of upper and lower diaphragms 36U and 36L, respectively.

  As shown in FIG. 3B, the foundation beam bracket 40 is joined to both ends of the foundation beam body 44, and forms the steel foundation beam 18 together with the foundation beam body 44. Specifically, one end of the foundation beam main body 44 is joined to the other end of the foundation beam bracket 40. The foundation beam main body 44 is formed of H-shaped steel, and includes a pair of upper and lower flange portions 44U and 44L and a web portion 44W that connects the pair of upper and lower flange portions 44U and 44L.

  As shown in FIG. 1, the web portion 44 </ b> W of the foundation beam main body 44 and the web portion 40 </ b> W of the foundation beam bracket 40 are joined by a bolt 48 and a nut (not shown) via a joining plate 46. Similarly, a pair of upper and lower flange portions 44U and 44L of the foundation beam main body 44 and a pair of upper and lower flange portions 40U and 40L of the foundation beam bracket 40 are connected to a bolt 52 and a nut via a joining plate (splice plate) 50. Are joined together.

  The other end portion of the foundation beam main body 44 is joined to another column foundation beam joint member via a foundation beam bracket (not shown). Moreover, the joining method of the foundation beam bracket 40 and the foundation beam main body 44 can be changed as appropriate, and may be welded, for example. Further, for example, a slab or the like may be formed on the steel foundation beam 18.

  The lower surface of the foundation beam bracket 40 (steel foundation beam 18), that is, the lower flange portion (lower flange portion) 40L is welded to the upper end portion 22U of the steel pipe 22. A plurality of studs 54 as a shearing force transmission mechanism are joined to the lower surface of the lower flange portion 40L. The plurality of studs 54 project downward from the lower surface of the lower flange portion 40 </ b> L, are disposed inside the steel pipe 22, and are embedded in the upper portion of the filling concrete 24. A shearing force is transmitted between the column foundation beam joint member 30 and the filled concrete 24 through these studs 54.

  Next, an example of the foundation construction method according to the first embodiment will be described.

  FIG. 3A shows a pile 14 embedded in the ground G. A pile head 14 </ b> A of the pile 14 protrudes upward from the ground G. From this state, first, the throwing cup 26 is placed in the periphery of the pile head 14A.

  Next, the column foundation beam joint member 30 to which the steel pipe 22 is welded in advance is lifted by a lifting machine such as a crane (not shown) with the steel pipe 22 facing down. Then, the suspended column foundation beam joint member 30 is lowered from the upper side of the pile head 14A to the lower side, and is installed on the dumping container 26 as shown in FIG. At this time, the pile head 14 </ b> A is inserted into the steel pipe 22 from the lower end side opening of the steel pipe 22. Moreover, the height of the steel pipe 22 etc. are adjusted suitably by throwing away the steel pipe 22 via the adjustment stand 28 and installing it on the condenser 26. Thereby, the column foundation beam joint member 30 is supported by the ground G through the steel pipe 22. That is, the steel pipe 22 functions as a temporary steel frame (base) for constructing the column foundation beam joint member 30.

  Next, the end portion of the foundation beam main body 44 is joined to the end portion of each foundation beam bracket 40 of the column foundation beam joint member 30 via the joining plates 46, 50 and the like to form the steel foundation beam 18.

  Next, as shown in FIG. 1, filled concrete 24 is filled into the inside of the steel pipe 22 from the upper end side opening of the steel pipe 22 and cured. At this time, the filling concrete 24 is filled up to the upper end 22U of the steel pipe 22, that is, the lower surface of the column foundation beam joint member 30. Thereby, the footing 20 which supports the pillar 16 standing above the said pile head 14A is formed around the pile head 14A. A plurality of studs 38 and 54 protruding from the column foundation beam joint member 30 to the inside of the steel pipe 22 are embedded in the upper portion of the filling concrete 24, and the column 16 is fixed to the filling concrete 24.

  Next, a column main body (not shown) is joined to the upper end portion of the column bracket 32, and concrete is filled in the column bracket 32 and the column main body to form the CFT column 16. Note that the pillar 16 may be S-shaped.

  Moreover, although the example which filled the inside of the steel pipe 22 with the filling concrete 24 after joining the foundation beam main body 44 to the foundation beam bracket 40 was shown above, it is not restricted to this. The filling timing (filling timing) of the filling concrete 24 into the steel pipe 22 can be appropriately changed. For example, before the foundation beam main body 44 is joined to the foundation beam bracket 40 or in parallel therewith, the filling concrete is filled in the steel pipe 22. 24 may be filled. In addition, for example, after the column main body is joined to the column bracket 32 to form (construct) the column 16, the filled concrete 24 may be filled into the steel pipe 22.

  Next, the operation and effect of the first embodiment will be described.

  As shown in FIG. 1, according to the present embodiment, the steel pipe 22 is welded to the column foundation beam joint member 30. A pile head 14 </ b> A of the pile 14 is inserted into the steel pipe 22. That is, the pile head 14 </ b> A of the pile 14 is surrounded by the steel pipe 22. By filling the steel pipe 22 with the filling concrete 24, the footing 20 that supports the column 16 standing above the pile head 14A is formed. That is, the steel pipe 22 functions as an embedded form for the footing 20. Therefore, it is not necessary to temporarily install and remove the mold for the footing 20.

  In this embodiment, the steel pipe 22 is filled with filled concrete 24 to form the CFT-like footing 20. In such a CFT-like footing 20, the steel pipe 22 resists tensile force and bending acting on the footing 20. Moreover, in the CFT-like footing 20, the restraining effect (confined effect) of the filled concrete 24 by the steel pipe 22 is obtained. Therefore, the reinforcing bars etc. in the filling concrete 24 can be reduced or eliminated. Therefore, the reinforcing bar construction of the footing 20 can be reduced.

  The steel pipe 22 also functions as a temporary steel frame for constructing the column foundation beam joint member 30. Therefore, it is not necessary to install and remove the temporary steel frame for constructing the column foundation beam joint member 30 separately from the steel pipe 22.

  As described above, in this embodiment, the reinforcement work for the footing 20 is reduced, and the temporary steel frame for constructing the column foundation beam joint member 30 is not required, thereby saving labor in the foundation 12 work. Can do.

  Furthermore, a foundation beam bracket 40 of a column foundation beam joint member 30 (steel foundation beam 18) is welded to the upper end portion 22U of the steel pipe 22. Thereby, when the filling concrete 24 is filled in the steel pipe 22, the displacement of the column foundation beam joint member 30 with respect to the steel pipe 22 is suppressed. Similarly, for example, when the end of the foundation beam main body 44 is joined to the end of the foundation beam bracket 40 or when a column main body (not shown) is joined to the column bracket 32, the column foundation beam processing for the steel pipe 22 is performed. The positional deviation of the mouth member 30 is suppressed. Therefore, since the workability of the foundation 12 is improved, labor saving can be achieved.

  In addition, by welding the upper end portion 22U of the steel pipe 22 and the foundation beam bracket 40 of the column foundation beam joint member 30, a shearing force is transmitted between the steel pipe 22 and the column foundation beam joint member 30 during an earthquake. The Therefore, the seismic performance is improved.

  A plurality of studs 38 and 54 are provided on the lower surface of the column foundation beam joint member 30. More specifically, a plurality of studs 38 and 54 projecting downward are provided on the lower surface of the lower diaphragm 36L of the column bracket 32 and the lower surface of the flange portion 40L on the lower side of the foundation beam bracket 40, respectively. . These studs 38 and 54 are arranged in the steel pipe 22 from the upper end side opening of the steel pipe 22 and are embedded in the upper part of the filling concrete 24. Thereby, a shearing force is transmitted between the column foundation beam joint member 30 and the filled concrete 24 via the plurality of studs 38 and 54.

  Further, the shearing force transmitted to the filling concrete 24 is a frictional force generated on the contact surface between the upper surface of the pile head 14A and the filling concrete 24, and the horizontal engagement between the pile head 14A and the filling concrete 24 (FIG. 1). Is transferred to the pile head 14A. Therefore, the seismic performance is improved.

  On the other hand, in the present embodiment, the column 16 does not bear the pulling force F or the pulling force F is small enough to be ignored in structural design. Therefore, pile head semi-rigidity is employable in this embodiment. Therefore, the pile head reinforcement of the pile head 14A can be omitted.

  Further, by making the diameter of the steel pipe 22 larger than the diameter of the pile head 14A, even if the pile core (center axis) of the pile 14 is displaced by several tens of millimeters due to a construction error, the column 16 is installed in a normal position as it is. be able to. Therefore, the workability of the foundation 12 is further improved.

  Next, a second embodiment will be described. Note that in the second embodiment, components similar to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  4 and 5 show a foundation 62 to which the foundation structure 60 according to the second embodiment is applied. In the second embodiment, the column 16 bears the pulling force F on the structural design. Therefore, a plurality of anchor members 64 as a pulling resistance mechanism are provided on the pile head 14 </ b> A of the pile 14. The plurality of anchor members 64 are arranged on the outer periphery of the pile head 14A at intervals in the circumferential direction of the pile head 14A, and extend upward from the pile head 14A.

  Each anchor member 64 is formed of a wire rod such as a reinforcing bar or a PC steel rod, and one end side (lower end side) is joined to the outer peripheral surface of the pile head 14A by welding or the like. On the other hand, the other end side (upper end side) of the anchor member 64 extends upward from the pile head 14 </ b> A, reaches the upper end portion 22 </ b> U of the steel pipe 72, and is embedded in the filling concrete 74 of the footing 70. That is, the anchor member 64 is disposed across the pile head 14A and the upper end portion 22U of the steel pipe 72 in a side view. Thereby, the fixing length of the anchor member 64 with respect to the filling concrete 74 is ensured.

  Further, a fixing body 66 such as a mechanical fixing embedded in the filling concrete 74 is provided at the other end (upper end) of the anchor member 64. The anchor member 64 improves the transmission efficiency of the pulling force F between the filling concrete 74 and the pile head 14A. The fixing member 66 can be omitted as appropriate.

  Further, as shown in FIG. 5, in the second embodiment, unlike the first embodiment, the steel pipe 72 of the footing 70 is a square steel pipe. Specifically, the steel pipe 72 has four side wall parts 72S. The four side wall portions 72S are formed of steel plates, and a rectangular tubular steel pipe 72 is formed in plan view by joining (welding) these steel plates. The steel pipe 72 may be a circular steel pipe.

  Also, as shown in FIG. 4, a plurality of shear keys 76 as a pulling force transmission mechanism are provided on the inner surface of each side wall 72S. The plurality of shear keys (pull-out force transmission ribs) 76 extend in the width direction of the respective side wall portions 72S and are arranged at intervals in the vertical direction. These shear keys 76 are embedded in filled concrete 74 filled in the steel pipe 72. Thereby, the integrity (adhesiveness) of the steel pipe 72 and the filling concrete 74 is improved. The upper end portion 72U of the steel pipe 72 is welded to the lower surface of the column foundation beam joint member 30 (steel foundation beam 18).

  A pulling force transmission plate 80 as a pulling force transmission mechanism is provided on the lower surface of the column foundation beam joint member 30. The pull-out force transmission plate 80 is formed by joining a plurality of steel plates 82 in a cross shape in plan view, and the upper ends of the pull-out force transmission plate 80 are the lower diaphragm 36L of the column bracket 32 and the lower flange of the foundation beam bracket 40. It is joined to the portion 40L by welding or the like.

  The pulling force transmission plate 80 protrudes downward from the lower surface of the column foundation beam joint member 30 and is disposed inside the steel pipe 72 and embedded in the filling concrete 74 above the pile head 14A. Accordingly, the column foundation beam joint member 30 is fixed to the filling concrete 74 via the pulling force transmission plate 80, and the pulling force between the column 16 and the filling concrete 74 is extracted via the pulling force transmission plate 80. F is transmitted. Further, the pulling force transmission plate 80 is provided with a shear key 84 similar to that of the steel pipe 72. The shear keys 76 and 84 can be omitted as appropriate.

  Further, as shown in FIG. 5, the side end portion of the pulling force transmission plate 80 is welded in a state of being abutted against the inner surface of the side wall portion 72 </ b> S of the steel pipe 72. The steel pipe 72 is reinforced by the pulling force transmission plate 80.

  Next, the operation and effect of the second embodiment will be described.

  According to the present embodiment, the plurality of anchor members 64 are provided on the pile head 14 </ b> A of the pile 14. These anchor members 64 extend upward from the pile head 14 </ b> A and are embedded in the filling concrete 74 of the footing 70.

  On the other hand, a pulling force transmission plate 80 is provided on the lower surface of the column foundation beam joint member 30. The pulling force transmission plate 80 extends from the lower surface of the column foundation beam joint member 30 into the steel pipe 72 and is embedded in the upper portion of the filled concrete 74. Thereby, for example, when a pulling force F acts on the column 16 during an earthquake, the pulling force F is transmitted to the filling concrete 74 via the column foundation beam joint member 30 and the pulling force transmission plate 80.

  Further, the pulling force F transmitted to the filling concrete 74 is transmitted to the pile head 14 </ b> A via the anchor member 64 and also transmitted to the ground G via the pile 14. Thereby, the floating of the pillar 16 at the time of an earthquake is suppressed. Therefore, the seismic performance is improved.

  Furthermore, in this embodiment, a plurality of shear keys 84 are provided on the pulling force transmission plate 80. When these shear keys 84 are engaged with the filling concrete 74 in the vertical direction, the transmission efficiency of the drawing force F between the drawing force transmission plate 80 and the filling concrete 74 is improved.

  The anchor member 64 is disposed across the pile head 14A and the upper end portion 22U of the steel pipe 72 in a side view. Thereby, the fixing length of the anchor member 64 with respect to the filling concrete 74 is ensured long. Further, a fixing body 66 embedded in the filling concrete 74 is provided at the upper end portion of the anchor member 64. Thereby, since the fixing strength of the anchor member 64 with respect to the filling concrete 74 is improved, the transmission efficiency of the extraction force F between the filling concrete 74 and the pile head 14A is improved.

  Furthermore, in the present embodiment, a plurality of shear keys 76 are provided on the inner surface of each side wall 72 </ b> S of the steel pipe 72. Accordingly, the pulling force F acting on the column 16 is transmitted from the column foundation beam joint member 30 to the filling concrete 74 through the steel pipe 72 and the shear key 76. Then, the pulling force F transmitted to the filling concrete 74 is transmitted to the pile head 14A via the plurality of anchor members 64 as described above. Therefore, the floating of the pillar 16 at the time of an earthquake is further suppressed.

  The pulling force transmission plate 80 may be joined to at least one of the column foundation beam joint member 30 and the steel pipe 72.

  Next, a third embodiment will be described. Note that in the third embodiment, components similar to those in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  6 and 7 show a foundation 92 to which the foundation structure 90 according to the third embodiment is applied. In the third embodiment, the foundation beam joint portion 32 </ b> S of the column bracket 32 is disposed in the steel pipe 96 of the footing 94 and embedded in the filled concrete 98 filled in the steel pipe 96.

  Specifically, as shown in FIG. 7, four notches 100 corresponding to the four foundation beam brackets 40 are formed in the upper portion of the steel pipe 96. Each notch 100 is formed by notching the steel pipe 96 downward from the upper end 96U. Further, each notch 100 is formed in a rectangular shape corresponding to the beam formation and beam width of the foundation beam bracket 40.

  The foundation beam bracket 40 is inserted into each notch portion 100, and the lower flange portion 40 </ b> L of the foundation beam bracket 40 is placed on the lower edge portion 100 </ b> L of the notch portion 100. In this state, for example, the pair of upper and lower flange portions 40U and 40L of the foundation beam bracket 40 and the side edge portion 100S and the lower edge portion 100L of the notch portion 100 are appropriately welded. That is, the foundation beam bracket 40 and the upper part of the steel pipe 96 are welded.

  In this state, as shown in FIG. 6, when filled concrete 98 is filled into the steel pipe 96, the foundation beam joint portion 32 </ b> S is embedded in the upper portion of the filled concrete 98, and the foundation beam bracket 40. The end on the foundation beam joint portion 32S side is embedded. Thereby, the pulling-out force F which acted on the pillar 16 at the time of an earthquake is transmitted to the filling concrete 98 via the foundation beam joint part 32S.

  It should be noted that at least one of the pair of upper and lower flange portions 40U, 40L of the foundation beam bracket 40 may be welded to the steel pipe 96. In addition, a gap is formed between the web portion 40W of the foundation beam bracket 40 and the side edge portion 100S of the notch portion 100, and the gap is appropriately closed by, for example, a conventional formwork.

  A plurality of shear keys 102 are provided on the inner surface of the steel pipe 96 to face the foundation beam joint 32S. A pulling force F is transmitted between the steel pipe 96 and the filled concrete 98 through these shear keys 102. A plurality of shear keys 104 facing the inner surface of the steel pipe 96 are provided on the outer surface of the foundation beam joint 32S. The drawing force F is transmitted between the foundation beam joint portion 32S and the filled concrete 98 through the plurality of shear keys 104. The shear keys 102 and 104 can be omitted as appropriate. In FIG. 7, the shear key 104 is not shown.

  In the third embodiment, the upper end sides of the plurality of anchor members 110 are arranged along the outer surface of the foundation beam joint portion 32S and reach the upper end portion 96U of the steel pipe 96. A pulling force F is transmitted between the filling concrete 98 and the pile head 14A through these anchor members 110. In addition, a fixing body 112 embedded in the filling concrete 98 is provided at the upper end portion of the anchor member 110. The fixing body 112 can be omitted as appropriate.

  Next, the operation and effect of the third embodiment will be described.

  As shown in FIG. 6, according to the present embodiment, the foundation beam joint portion 32 </ b> S of the column foundation beam joint member 30 is embedded in the filling concrete 98 and the foundation beam joint portion 32 </ b> S of the foundation beam bracket 40. The end on the side is embedded in the filled concrete 98. Thereby, the fixing degree of the column base part of the column 16 with respect to the footing 94 is raised. Therefore, the seismic performance is improved.

  Further, by burying the foundation beam joint portion 32S in the filling concrete 98, the pulling force F acting on the column 16 is transmitted to the filling concrete 98 via the foundation beam joint portion 32S in the event of an earthquake. Further, in the present embodiment, a plurality of shear keys 104 are provided on the outer surface of the foundation beam joint 32S. Thereby, the transmission efficiency of the drawing force F between the pillar 16 and the filling concrete 98 improves.

  Furthermore, the pulling force F acting on the column 16 is transmitted from the steel pipe 96 welded to the foundation beam bracket 40 to the filling concrete 98 through the plurality of shear keys 102. Therefore, the transmission efficiency of the drawing force F between the column 16 and the filled concrete 98 is further improved.

  The pulling force F transmitted to the filled concrete 98 is transmitted to the pile head 14A via the anchor member 110 embedded in the filled concrete 98 and also transmitted to the ground G via the pile 14. Thereby, the floating of the pillar 16 at the time of an earthquake is suppressed. Therefore, the seismic performance is improved.

  Further, as described above, by arranging the anchor member 110 along the outer surface of the foundation beam joint portion 32S, that is, in a side view, the foundation beam joint portion 32S and the upper end side of the anchor member 110 are wrapped. Thereby, the transmission efficiency of the drawing force F between the pillar 16 and the pile 14 is improved.

  Next, modified examples of the first to third embodiments will be described. In the following, various modified examples will be described taking the first embodiment as an example, but these modified examples can be applied to the second and third embodiments as appropriate.

  In the first embodiment, a plurality of studs 38 and 54 as shear force transmission mechanisms are provided on the lower surface of the column foundation beam joint member 30. However, the number and arrangement of these studs 38 and 54 can be changed as appropriate. is there. For example, a shearing force transmission mechanism such as a stud may be provided on the inner surface of the steel pipe 22. That is, the shear force transmission mechanism can be provided in at least one of the column 16, the steel foundation beam 18, and the steel pipe 22. Furthermore, shear force transmission mechanisms such as the studs 38 and 54 can be omitted as appropriate.

  Moreover, in the said 1st Embodiment, although the steel pipe 22 is welded beforehand to the column foundation beam joint member 30, you may weld the column foundation beam joint member 30 and the steel pipe 22 on-site. In this case, for example, what is welded to the column foundation beam joint member 30 and the steel pipe 22 may be installed on the ground G. First, the steel pipe 22 is first installed on the ground G, and then the steel pipe. The column foundation beam joint member 30 may be installed on 22 and the steel pipe 22 and the column foundation beam joint member 30 may be welded.

  In the first embodiment, the column foundation beam joint member 30 is formed by the column bracket 32 and the plurality of foundation beam brackets 40. However, the first embodiment is not limited thereto. The column foundation beam joint member may be formed by the foundation beam joint portion 32S and the foundation beam bracket 40, for example. In this case, for example, after the column foundation beam joint member is installed on the ground G via the steel pipe 22, the column 16 is joined to the foundation beam joint portion 32S.

  Moreover, in the said 1st Embodiment, although the four foundation beam brackets 40 were provided in the column foundation beam joint member 30, the number and arrangement | positioning of the foundation beam brackets 40 can be changed suitably. For example, the column foundation beam joint member 30 may be provided with a plurality of foundation beam brackets 40 in a cross shape, a G shape, an L shape, or an I shape in plan view.

  Moreover, in the said 1st Embodiment, although the filling concrete 24 was filled to the upper end part 22U in the steel pipe 22, the said 1st Embodiment is not restricted to this. The filling amount of the filling concrete 24 into the steel pipe 22 can be changed as appropriate. In addition, concrete may be placed up to the top of the steel foundation beam 18 around the foundation beam joint 32S, and the foundation beam joint 32S may be embedded in the concrete.

  Moreover, in the said 1st Embodiment, although the steel foundation beam 18 (foundation beam bracket 40, the foundation beam main body 44) is formed with a H-shaped steel, the steel foundation beam 18 is, for example, an I-shaped steel, a C-shaped steel, It may be formed of box steel or the like. Similarly, in the above embodiment, the column 16 is formed of a square steel pipe, but the column may be formed of a circular steel pipe, an H-shaped steel, or the like. Furthermore, the pillar is not limited to CFT construction, but may be S construction, RC construction, or SRC construction.

  The first to third embodiments of the present invention have been described above. However, the present invention is not limited to such embodiments, and the first to third embodiments and various modifications may be used in appropriate combination. It goes without saying that the present invention can be carried out in various modes without departing from the gist of the present invention.

10 Foundation Structure 14 Pile 14A Pile Head 16 Column 18 Steel Foundation Beam 20 Footing 22 Steel Pipe 24 Filled Concrete 38 Stud (Shear Force Transmission Mechanism)
54 Stud (Shearing force transmission mechanism)
60 Foundation structure 64 Anchor member (Pullout resistance mechanism)
72 Steel pipe 74 Filled concrete 90 Foundation structure 96 Steel pipe 98 Filled concrete 110 Anchor member (pullout resistance mechanism)
G ground

Claims (3)

A pile on the ground,
A steel pipe surrounding the pile head of the pile;
A steel foundation beam that is installed on the steel pipe and is joined to the steel pipe and welded to a column that stands above the pile head;
Filled concrete that fills the steel pipe and forms a footing that supports the column;
Basic structure with At least one of the steel pipe, the column and the steel foundation beam is provided with a shear force transmission mechanism embedded in the filled concrete.
The foundation structure according to claim 1. The pile head is provided with a pulling resistance mechanism that extends upward and is embedded in the filled concrete.
The foundation structure according to claim 1 or claim 2.

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