Pillar-and-pile junction structure

Abstract

To improve the rationality and economy of a structure, as well as the efficiency of the jointing work, in a pillar-and-pile junction structure that directly joins a pillar and a pile, thereby omitting foundation footing and a footing beam.SOLUTION: There is provided a pillar-and-pile junction structure in which a base plate and an anchor pipe that extends downward from the base plate to a position higher than the top end of the pile with external dimensions smaller than the pillar are provided at the bottom end of the pillar, multiple studs that extend upward to surround the anchor pipe are provided at the top end of the pile, a hoop reinforcement that surrounds the multiple studs from the outer peripheral side is provided, and concrete is filled in the space from a part of the pile that protrudes above the ground to the underside of the base plate to surround the anchor pipe, the multiple studs and the hoop reinforcement.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a joint structure between a pillar and a pile. [Background technology]

[0002] The most common method of connecting piles to the superstructure is to use reinforced concrete footings or foundation beams, but this requires complicated reinforcement work and increases the amount of soil that needs to be excavated from the ground, which hinders efforts to reduce costs and shorten construction periods.

[0003] Therefore, in order to reduce the amount of excavated soil, attempts have been made to omit the foundation footing and foundation beams and instead directly join the piles and columns.

[0004] For example, in the joint structure between a steel column and a precast pile disclosed in Patent Document 1, an enlarged head is provided at the upper end of the precast pile, and the base of the steel beam is fixed to the concrete filled in the enlarged head to join the steel beam and the precast pile. This structure increases the degree of freedom of the planar joint position of the steel column, absorbs construction errors that occur when driving the precast pile, and improves construction efficiency. In addition, the enlarged head provided at the upper end of the precast pile is wrapped in reinforced concrete at the fixed part of the base of the steel column, making it possible to firmly join the steel column and the precast pile.

[0005] In addition, in the joint structure between a pile and a column disclosed in Patent Document 2, a shear key (anchor pipe) that extends downward from the base plate and has an outer dimension smaller than that of the column is provided at the lower end of the column. Then, with the shear key of the lower end of the column inserted into the upper end of the pile having a hollow cross section, the pile and the column are joined by filling the space from the upper end of the pile to at least the lower surface of the base plate of the front column with concrete so as to cover the periphery of the shear key. This structure simplifies the structure and reduces costs by reducing the amount of excavated soil and the amount of steel used, and by adjusting the joint form to a semi-rigid joint, the bending moment transmitted from the upper column to the joint is reduced, improving rationality and economy. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-255003 A [Patent Document 2] Patent Publication No. 2022-162221 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the joint structure between a steel column and a prefabricated pile disclosed in Patent Document 1, the base of the steel beam is directly inserted into the enlarged head provided at the upper end of the prefabricated pile, or an anchor bolt that fastens the base plate of the base of the steel beam is inserted, and the prefabricated pile is fixed to the concrete inside the enlarged head.

[0008] For this reason, the inside diameter of the enlarged head at the top end of the precast pile needs to be larger than the outside dimension of the steel column or the spacing between the anchor bolts. Therefore, when the outside dimension of the steel column is large or the outside diameter of the precast pile is small, the effect of increasing the degree of freedom of the planar joint position of the steel column is difficult to achieve.

[0009] In addition, the joint structure between a steel column and a precast pile disclosed in Patent Document 1 describes a strong joint between the steel column and the precast pile, i.e., a rigid joint. However, in general, it is more advantageous in terms of design to connect the steel column and the precast pile with a semi-rigid joint.

[0010] Furthermore, in the joint structure between a pile and a column disclosed in Patent Document 2, a shear key is provided so as to extend downward from the lower end of the column, and is inserted into the upper end of the pile having a hollow cross section. Concrete is then filled in so as to cover the periphery of the shear key, thereby joining the pile and the column.

[0011] For this reason, in the joint structure described in Patent Document 2, it is necessary to excavate and remove the soil from within the upper end of the pile so that the shear key of the lower end of the column can be inserted into the upper end of the pile having a hollow cross section, which requires time and cost for the joint work. In addition, the outer dimensions of the shear key provided at the lower end of the column greatly affect the strength and rigidity of the joint structure between the pile and the column, and since the outer dimensions of the shear key need to be smaller than the inner diameter of the upper end of the pile, the performance of the joint structure between the pile and the column is limited by the specifications of the pile.

[0012] The present invention has been made to solve the above problems, and aims to improve the rationality and economy of the structure and the efficiency of the joining work in a column-pile joint structure in which the column and the pile are directly joined to omit the foundation footing and foundation beam. Specifically, the present invention aims to improve the efficiency and economy of the joining work between the column and the pile by increasing the degree of freedom of the planar joining position of the column and reducing the amount of excavated soil. In addition, the present invention aims to improve the rationality and economy of the entire structure by reducing the bending moment transmitted to the joint from the upper column by making the joining form between the column and the pile a semi-rigid joint. [Means for solving the problem]

[0013] The means for solving the above problems are as follows. [1] A joint structure between a pillar and a pile, comprising: a base plate at the lower end of the pillar; and an anchor pipe extending downward from the base plate to a position higher than the upper end of the pile and having an outer dimension smaller than that of the pillar; a plurality of studs extending upward to surround the anchor pipe at the upper end of the pile; hoop reinforcement surrounding the plurality of studs from the outer periphery; and a space from the part of the pile protruding above the ground to at least the underside of the base plate is filled with concrete to cover the anchor pipe, the plurality of studs and the hoop reinforcement.

[0014] In general, crushed stone is laid in the ground at the bottom of the space where the concrete will be filled, and then concrete is poured in. In this case, the "portion of the pile protruding above the ground" refers to the portion of the pile that protrudes above the crushed stone and concrete. [2] The column-pile joint structure described in [1], wherein the hoop reinforcement is arranged in a position contacting the stud. [3] A joint structure between a column and a pile as described in [1] or [2], in which reinforcing hoops are provided to further surround the hoops from the outer periphery. [4] A column-pile joint structure as described in [1] or [2], in which a stiffener is provided between the base plate and the anchor pipe. [5] A column-pile joint structure as described in [1] or [2], wherein an engagement portion is provided on the underside of the base plate to engage with the concrete. [6] A joint structure between a pillar and a pile described in [1] or [2], in which a plurality of construction anchor bolts are installed on the ground or fixed to the upper ends of the piles so as to surround the portions of the piles protruding above the ground, and the base plate is provided with construction fastening portions, and the pillars are positioned relative to the piles by fastening the construction fastening portions to the construction anchor bolts. Effect of the Invention

[0015] According to the column-pile joint structure of the present invention, the column and pile are directly joined, eliminating the need for foundation footings or foundation beams, thereby reducing the amount of excavated soil and steel used, thereby simplifying the structure and reducing costs.

[0016] Furthermore, the outer dimensions of the anchor pipe attached to the lower end of the pillar are smaller than those of the pillar, and the extension length of the anchor pipe is set to a position higher than the upper end of the pile, so it is not inserted into the upper end of the pile. This increases the degree of freedom of the planar joint position of the pillar, reduces the amount of excavated soil, and improves the efficiency and economy of the work of joining the pillar and the pile.

[0017] The pile and the column are then joined by filling concrete so as to cover the anchor pipe, stud bolt, and hoop reinforcement, which have smaller outer dimensions than the column. This makes the column-pile joint a semi-rigid joint, reducing the bending moment transmitted from the column above to the joint, and improving the rationality and economy of the entire structure. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing an example of a building to which the column-pile joint structure of the present invention is applied. [Diagram 2] 2(a) and 2(b) are a vertical cross-sectional view and a plan view showing an example of a joint structure between a pillar and a pile according to the present invention. [Diagram 3] 3(a) and 3(b) are a vertical cross-sectional view and a plan view showing another example of a joint structure between a pillar and a pile according to the present invention. [Figure 4] FIG. 4 is a vertical cross-sectional view showing still another example of the joint structure between a pillar and a pile of the present invention. [Diagram 5] FIG. 5 is a vertical cross-sectional view showing still another example of the joint structure between a pillar and a pile of the present invention. [Figure 6] FIG. 6 is a vertical cross-sectional view showing still another example of the joint structure between a pillar and a pile according to the present invention. [Figure 7] FIG. 7 is a vertical cross-sectional view showing still another example of the joint structure between a pillar and a pile of the present invention. [Figure 8] FIG. 8 is a vertical cross-sectional view showing still another example of the joint structure between a pillar and a pile of the present invention. [Figure 9] 9(a) and 9(b) are a plan view and a vertical cross-sectional view showing a construction procedure for the joint structure between a pillar and a pile of the present invention. [Figure 10] 10(a) and 10(b) are a plan view and a vertical cross-sectional view showing a construction procedure for the joint structure between a pillar and a pile of the present invention. [Figure 11] 11(a) and 11(b) are a plan view and a vertical sectional view showing a construction procedure for the joint structure between a pillar and a pile of the present invention. [Figure 12]12(a) and 12(b) are a plan view and a vertical cross-sectional view showing a construction procedure for the joint structure between a pillar and a pile of the present invention. [Figure 13] 13(a) and 13(b) are a plan view and a vertical sectional view showing a construction procedure for the joint structure between a pillar and a pile of the present invention. [Figure 14] 14(a) and 14(b) are a plan view and a vertical sectional view showing a construction procedure for the joint structure between a pillar and a pile of the present invention. [Figure 15] 15(a) and 15(b) are a plan view and a vertical sectional view showing a construction procedure for the joint structure between a pillar and a pile of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the joint structure between a column and a pile of the present invention will be specifically described with reference to the drawings. The joint structure between a column and a pile of the present invention is applied to a portion where a large pull-out force is not applied to the column, such as a portion where the column and the pile of a low-rise building are joined. <Column and pile joint structure> [First embodiment] Fig. 1 shows a perspective view of a building to which the joint structure between a column and a pile according to the first embodiment of the present invention is applied. Fig. 2(a) and Fig. 2(b) show a vertical cross-sectional view and a plan view of the joint structure between a column and a pile according to the first embodiment.

[0020] As shown in Fig. 1, the column-pile joint structure of the first embodiment is used at a location where a steel column 2 of a low-rise steel-framed building is joined to a PHC pile (centrifugally formed prestressed high-strength concrete pile) 1 having a hollow cross section. As shown in Fig. 1, no foundation beam or footing is provided at the base of the steel column 2 of this steel-framed building, and the PHC pile 1 is directly joined to each base of the steel column 2.

[0021] Specifically, as shown in Figures 2(a) and 2(b), pre-boring is performed in the excavated part of the ground G, and a base consolidation liquid (not shown) and a pile circumference fixing liquid (not shown) are injected, and then the PHC pile 1 is sunk and erected in a state in which its upper part protrudes from the excavated surface of the ground G. In the excavated part of the ground G, crushed stone 61 is laid around the PHC pile 1, and furthermore, basing concrete 62 is poured. In this embodiment, the PHC pile 1 protruding above the ground G is erected in a state in which it protrudes, for example, 75 mm from the upper end of the basing concrete 62.

[0022] On the other hand, at the lower end of the steel column 2, a base plate 21 and an anchor pipe 23 extending downward from the base plate 21 to a position higher than the upper end of the PHC pile 1 and having an outer dimension smaller than that of the steel column 2 are provided. In the joint structure between the column and the pile of this embodiment, the anchor pipe 23 is made of a seamless steel pipe, and is a structure applicable to places where high strength and resistance are required, but the anchor pipe 23 may be made of other steel pipes, shaped steel, etc. In addition, when the joint structure between the column and the pile of this embodiment is used for a column base to which a brace is not attached, the anchor pipe 23 may be made of an extremely thick reinforcing bar or other steel bar to reduce the bending rigidity of the joint between the PHC pile 1 and the steel column 2. In this way, the bending moment generated at the pile head of the PHC pile 1 and the column base of the steel column 2 is reduced, and a rational structure can be obtained.

[0023] 2(a) and 2(b), a support plate 24 is provided at the lower end of the anchor pipe 23, protruding laterally from the anchor pipe 23. In addition, a stiffener 26 is provided between the base plate 21 and the anchor pipe 23 to stiffen the space between them, increasing the strength and rigidity of the base plate 21.

[0024] 2(a) and 2(b), a plurality of stud bolts 13 extending upward from the pile body are provided on a ring-shaped end plate 11 provided at the upper end of the PHC pile 1 so as to surround the anchor pipe 23. Specifically, screw holes are provided at predetermined intervals in the end plate 11 of the PHC pile 1, and the lower ends of the stud bolts 13 are screwed into each of the screw holes to provide the stud bolts 13 extending upward from the end plate 11.

[0025] Alternatively, instead of the above-mentioned structure, a stacked plate having a planar shape similar to that of the ring-shaped end plate 11 provided at the upper end of the PHC pile 1 is prepared, and a stud made of a deformed reinforcing bar or a bolt is previously joined by welding or the like to the upper surface of the stacked plate. Then, the stacked plate may be fixed to the end plate 11 at the upper end of the PHC pile 1 by fastening the bolt or the like, thereby providing a stud extending upward from the end plate 11. Furthermore, as shown in Figures 2(a) and 2(b), three rows of hoop reinforcement bars 14 are provided on the outer periphery of the multiple stud bolts 13 extending upward from the upper end of the PHC pile 1 so as to surround the multiple stud bolts 13 from the outer periphery. Each hoop reinforcement bar 14 is wound around the outside of the stud bolt 13 so as to be in contact with the stud bolt 13, and is fastened to the stud bolt 13 by a binding wire, spot welding, or the like. The hoop reinforcement bars 14 are provided with a strength of, for example, 785 N / mm 2 grade (yield strength is 785N / mm 2 It is preferable to use a high-strength welded closed hoop reinforcement such as a reinforcing bar specified as above, since this effectively increases the shear strength and shear resistance of the concrete 4 described below.

[0026] As shown in Fig. 2(a) and Fig. 2(b), the space from the part where the PHC pile 1 protrudes above the ground G to the bottom surface of the base plate 21 is filled with concrete 4 so as to cover the anchor pipe 23, the stud bolt 13, and the hoop reinforcement 14. In this embodiment, crushed stone 61 is laid in the ground G, which is the bottom end of the space where the concrete 4 is filled, and mortar concrete 62 is further poured. The "part where the PHC pile 1 protrudes above the ground G" refers to the part of the PHC pile 1 that protrudes above the crushed stone 61 and the mortar concrete 62. The protruding height of the PHC pile 1 that protrudes above the mortar concrete 62 is preferably set within a range of, for example, 75 to 150 mm. In this way, the PHC pile 1 and the steel column 2 are joined together.

[0027] In the joint structure between the column and the pile of this embodiment, a plurality of construction anchor bolts 31 are provided on the waste concrete 62 in the excavated portion of the ground G so as to surround the portion of the PHC pile 1 that protrudes above the ground G. In addition, a construction fastening portion 32 made of a steel plate is welded to the side edge of the base plate 21 of the PHC pile 1. The construction fastening portion 32 is formed by, for example, combining two steel plates with a thickness of 40 mm, and a bolt hole (not shown) is provided at a position corresponding to the construction anchor bolt 31. The construction fastening portion 32 is fastened to the construction anchor bolt 31 by screwing a nut 33 onto the construction anchor bolt 31 that protrudes above the construction fastening portion 32 from the bolt hole. In this way, the steel column 2 is positioned relative to the PHC pile 1.

[0028] A floor slab (not shown) may be provided around the base of the steel column 2, if necessary.

[0029] In this embodiment, the stiffener 26 is not necessarily required, but in order to adjust the joint form between the column and the pile to a semi-rigid joint, it is preferable to provide the stiffener 26 as in this embodiment as necessary to increase the strength and rigidity of the base plate 21. [Second embodiment] 3(a) and 3(b) show a longitudinal section and a plan view of a joint structure between a column and a pile according to a second embodiment of the present invention. In the joint structure between a column and a pile according to the second embodiment, the same components as those in the joint structure between a column and a pile according to the first embodiment are given the same reference numerals, and the description thereof will be omitted.

[0030] As shown in Figures 3(a) and 3(b), in the column-pile joint structure of the second embodiment, reinforcing hoops 15 are provided in three stages so as to further surround from the outer periphery the hoops 14 in each stage in the column-pile joint structure of the first embodiment. The reinforcing hoops 15 are fixed by means of dice (not shown) or the like provided on the basing concrete 62. The reinforcing hoops 15 are provided with a strength of, for example, 785 N / mm, similar to the hoops 14. 2 grade (yield strength is 785N / mm 2 It is preferable to use a high-strength welded closed hoop reinforcement such as a reinforcing bar specified as above, since the shear strength and shear resistance of the concrete 4 can be effectively increased.

[0031] Then, as shown in Figures 3(a) and 3(b), concrete 4 is filled in the space from the part of the PHC pile 1 that protrudes above the crushed stone 61 and basing concrete 62 provided on the ground G to the underside of the base plate 21 so as to cover the anchor pipe 23, the stud bolt 13, the hoop 14, and the reinforcing hoop 15. In this way, the PHC pile 1 and the steel column 2 are joined. In other respects, the joint structure between the column and the pile in the second embodiment is configured similarly to the joint structure between the column and the pile in the first embodiment.

[0032] As in the second embodiment, by providing reinforcing hoops 15 so as to surround the hoops 14 from the outer periphery, a joint structure that can withstand a larger shear force can be obtained. In addition, while maintaining the shear resistance of the joint structure between the column and the pile, the horizontally flat shape can be made to reduce the height, resulting in an economical structure. [Third embodiment] A longitudinal sectional view of a joint structure between a pillar and a pile according to a third embodiment of the present invention is shown in Fig. 4. In the joint structure between a pillar and a pile according to the third embodiment, the same components as those in the joint structure between a pillar and a pile according to the second embodiment are given the same reference numerals, and the description thereof will be omitted.

[0033] As shown in Fig. 4, in the joint structure between a column and a pile of the third embodiment, the stiffener 26 in the joint structure between a column and a pile of the second embodiment is omitted. In other respects, the joint structure between a column and a pile of the third embodiment is configured similarly to the joint structure between a column and a pile of the second embodiment.

[0034] As in the third embodiment, by omitting the stiffener 26 that stiffens the space between the base plate 21 and the anchor pipe 23, it is possible to adjust the bending rigidity of the joint between the PHC pile 1 and the steel column 2 to be small, thereby reducing the bending moment transmitted to the joint from the upper steel column 2. In addition, by yielding the base plate 21 and causing bending deformation, it is possible to ensure sufficient plastic deformation capacity. [Fourth embodiment] A vertical cross-sectional view of a joint structure between a pillar and a pile according to a fourth embodiment of the present invention is shown in Fig. 5. In the joint structure between a pillar and a pile according to the fourth embodiment, the same components as those in the joint structure between a pillar and a pile according to the third embodiment are given the same reference numerals, and the description thereof will be omitted.

[0035] As shown in Figure 5, in the pillar-pile joint structure of the fourth embodiment, in addition to the support plate 24 that is provided at the lower end of the anchor pipe 23 and protrudes laterally in the pillar-pile joint structure of the third embodiment, a support plate 25 that protrudes laterally from the anchor pipe 23 is also provided at the middle part of the anchor pipe 23.

[0036] In other respects, the joint structure between a pillar and a pile in the fourth embodiment is configured similarly to the joint structure between a pillar and a pile in the third embodiment.

[0037] As in the fourth embodiment, by providing the support plates 24, 25 protruding laterally from the anchor pipe 23 at a plurality of locations, a joint structure capable of withstanding even greater axial forces can be obtained. [Fifth embodiment] A vertical cross-sectional view of a joint structure between a pillar and a pile according to a fifth embodiment of the present invention is shown in Fig. 6. In the joint structure between a pillar and a pile according to the fifth embodiment, the same components as those in the joint structure between a pillar and a pile according to the third embodiment are given the same reference numerals, and the description thereof will be omitted.

[0038] As shown in Fig. 6, in the column-pile joint structure of the fifth embodiment, an engagement portion 22 that engages with concrete 4 is provided on the underside of the base plate 21 of the steel column 2 in the column-pile joint structure of the third embodiment. For the engagement portion 22, for example, a flat bar having a size of about 25 mm x 32 mm x 450 mm can be used.

[0039] In other respects, the joint structure between a pillar and a pile in the fifth embodiment is configured similarly to the joint structure between a pillar and a pile in the third embodiment.

[0040] As in the fifth embodiment, by providing an engagement portion 22 that engages with the concrete 4 on the underside of the base plate 21 of the steel column 2, a joint structure that can withstand a larger shear force is obtained. This is because, when a shear force acts from the steel column 2 to the PHC pile 1, a concrete strut is formed between the steel column 2 and the horizontal lateral part of the inner surface of the upper end of the PHC pile 1. [Sixth embodiment] A longitudinal sectional view of a joint structure between a pillar and a pile according to a sixth embodiment of the present invention is shown in Fig. 7. In the joint structure between a pillar and a pile according to the sixth embodiment, the same components as those in the joint structure between a pillar and a pile according to the fifth embodiment are given the same reference numerals, and the description thereof will be omitted.

[0041] 7, in the sixth embodiment, the pillar-pile joint structure is the same as the fifth embodiment, except that a reinforcing band 16 is wound around the outer periphery of the upper end of the PHC pile 1. The reinforcing band 16 is formed by winding a steel plate, steel wire, or wire made of carbon fiber or the like around the outer periphery of the upper end of the PHC pile 1.

[0042] In other respects, the joint structure between a pillar and a pile in the sixth embodiment is configured similarly to the joint structure between a pillar and a pile in the fifth embodiment.

[0043] As in the sixth embodiment, a reinforcing band 16 is wrapped around the outer periphery of the upper end of the PHC pile 1 to resist the circumferential stress of the PHC pile 1, thereby increasing the resistance to loads acting horizontally on the inner surface of the upper end of the PHC pile 1, and resulting in a joint structure that can withstand even larger shear forces and bending moments at the column base. [Seventh embodiment] A longitudinal sectional view of a joint structure between a pillar and a pile according to a seventh embodiment of the present invention is shown in Fig. 8. In the joint structure between a pillar and a pile according to the seventh embodiment, the same components as those in the joint structure between a pillar and a pile according to the second embodiment are given the same reference numerals, and the description thereof will be omitted.

[0044] As shown in Fig. 8, in the column-pile joint structure of the seventh embodiment, the construction anchor bolt 31 in the column-pile joint structure of the second embodiment is provided not on the basin concrete 62 but on an extension to the outer periphery of the overlapping plate 12 provided at the upper end of the PHC pile 1, and is fastened with a nut 34. Then, the construction fastening part 32 welded to the side edge of the base plate 21 of the PHC pile 1 is fastened with a nut 33 to the construction anchor bolt 31, thereby positioning the steel column 2 with respect to the PHC pile 1.

[0045] In other respects, the joint structure between a pillar and a pile in the seventh embodiment is configured similarly to the joint structure between a pillar and a pile in the second embodiment.

[0046] In the joint structure between a pillar and a pile in each of the above embodiments, the strength and rigidity of the joint structure between the pillar and the pile can be adjusted to a desired value by appropriately changing the shape, dimensions and strength of each component. For example, the plate thickness of the base plate 21, the size of the engagement portion 22, the outer dimensions and wall thickness of the anchor pipe 23, the plate thickness, protruding width, number and arrangement of the bearing plates 24, 25, the plate thickness, number and arrangement of the stiffener 26, the insertion depth into the upper end of the PHC pile 1, etc. can be adjusted. This makes it possible to adjust the compressive strength, tensile strength, bending strength, shear strength, compressive rigidity, tensile rigidity, bending rigidity and shear rigidity of the joint structure between the pillar and the pile.

[0047] By making such adjustments, for example, the joint structure between a pillar and a pile can be made semi-rigid, reducing the bending force generated at the joint, enabling economical design of the entire joint structure.

[0048] As described above, the column-pile joint structure of the present invention is applied to a portion where a large pull-out force is not applied to the column, such as a portion where the column and pile of a low-rise building are joined, but for example, when a brace is provided between the steel columns 2, an axial tensile force acts between the PHC pile 1 and the steel column 2. Therefore, it is preferable to make the above-mentioned adjustment so as to withstand this axial tensile force. <Construction method for joint structure between pillar and pile> A construction method for the joint structure between a pillar and a pile in each of the above-mentioned embodiments will be described with reference to Fig. 9 to Fig. 15. Hereinafter, the construction of the joint structure between a pillar and a pile in the third embodiment will be described.

[0049] First, as shown in the plan view of FIG. 9(a) and the vertical cross-sectional view of FIG. 9(b), the ground G is excavated, pre-bored in the excavation, and a base-hardening liquid (not shown) and a pile-periphery fixing liquid (not shown) are injected. The pile-periphery fixing liquid protects the wall of the borehole when the PHC pile 1 is erected, and fills the gap between the hole wall and the PHC pile 1 to ensure adhesion to the surrounding ground. When the PHC pile 1 is sunk in the borehole, the pile-periphery fixing liquid also flows into the hollow part of the PHC pile 1. A ring-shaped end plate 11 is provided in advance at the upper end of the PHC pile 1. At this time, the upper end of the PHC pile 1 (for example, a part about 300 mm from the upper end of the PHC pile 1) is made to protrude from the surface of the ground G at the excavation part.

[0050] When erecting the PHC pile 1 into the ground G, it is not necessarily necessary to use a fixing fluid around the pile.

[0051] Next, as shown in the plan view of Fig. 10(a) and the vertical cross-sectional view of Fig. 10(b), the stud bolts 13 are screwed into each screw hole of the ring-shaped end plate 11 provided at the upper end of the PHC pile 1. This results in multiple stud bolts 13 extending upward from the pile body so as to surround the anchor pipe 23.

[0052] Next, as shown in the plan view of Fig. 11(a) and the vertical cross-sectional view of Fig. 11(b), crushed stone 61 is laid in the excavated portion of the ground G so as to surround the periphery of the PHC pile 1, and basing concrete 62 is poured. At this time, a plurality of construction anchor bolts 31 are installed on the ground G so as to surround the portion of the PHC pile 1 installed on the ground G that protrudes above the ground G, and are fixed to the basing concrete 62 in the excavated portion of the ground G.

[0053] 11(a) and 11(b), depending on the design of the building, the conditions at the construction site, etc., the reference axis for the arrangement of the multiple construction anchor bolts 31 may be offset horizontally by a predetermined dimension (e.g., 80 mm) with respect to the pile core of the PHC pile 1. At this time, the column core position on the basing concrete 62 is marked out, and the reference axes for the arrangement of the multiple construction anchor bolts 31 are aligned with this marking and fixed to the basing concrete 62. The construction anchor bolt 31 is provided to temporarily support one section of the column base of the steel column 2 in order to position the steel column 2 with respect to the PHC pile 1.

[0054] Next, as shown in the plan view of Fig. 12(a) and the vertical cross-sectional view of Fig. 12(b), hoops 14 are installed on the outer periphery of the multiple stud bolts 13 extending upward from the upper end of the PHC pile 1 so as to surround these multiple stud bolts 13 from the outer periphery. At this time, each hoop 14 is placed so as to be in contact with the stud bolt 13, and is fastened to the stud bolt 13 by a tie wire, spot welding, or the like. Also, reinforcing hoops 15 are installed on the basing concrete 62 using a die (not shown) or the like so as to further surround the hoops 14 from the outer periphery.

[0055] Next, as shown in the plan view of FIG. 13(a) and the vertical cross-sectional view of FIG. 13(b), a steel plate-made erection fastening portion 32 is welded to the side edge of the base plate 21 of the PHC pile 1. In this state, the steel column 2 is erected by inserting the anchor pipe 23 of the steel column 2 inside the multiple stud bolts 13 and the hoop reinforcement 14 provided at the upper end of the PHC pile 1. At this time, the erection anchor bolts 31 are inserted into the bolt holes provided in the erection fastening portion 32. Then, the level of the steel column 2 is adjusted, and the nuts 33 are screwed onto the erection anchor bolts 31 to fasten the erection fastening portion 32 to the erection anchor bolts 31 for temporary fixation.

[0056] Next, as shown in the plan view of FIG. 14(a) and the vertical cross-sectional view of FIG. 14(b), for example, a circular temporary formwork (temporary formwork) 5 is installed so as to surround the outer periphery of the part of the PHC pile 1 that protrudes above the ground G. Furthermore, as shown in the plan view of FIG. 15(a) and the vertical cross-sectional view of FIG. 15(b), the space from the part of the PHC pile 1 that protrudes above the ground G to the underside of the base plate 21 of the steel column 2 is filled with concrete 4 so as to cover the periphery of the anchor pipe 23, and then hardened. At this time, since the inside of the PHC pile 1 is filled with a pile periphery fixing liquid, it is not necessary to provide a formwork for forming the underside of the concrete 4 inside the PHC pile 1 below the anchor pipe 23. Also, as described above, when erecting the PHC pile 1 into the ground G, it is not necessary to use the pile periphery fixing liquid. In this case, it is not necessary to provide a formwork for forming the underside of the concrete 4 inside the PHC pile 1, and it is sufficient that the periphery of the anchor pipe 23 is completely covered by the concrete 4. If the internal space of the PHC pile 1 is hollow and not filled with excavated soil or the like, a temporary formwork for forming the underside of the concrete 4 can be provided below the anchor pipe 23 as necessary to save the amount of concrete 4. This completes the construction of the joint structure between the column and the pile. After that, a floor slab 7 can be provided around the base of the steel column 2 as shown in Figure 15(b) as necessary.

[0057] A reusable formwork may be used instead of the circular disposable formwork 5, but using a disposable formwork can improve the safety and efficiency of the work. Also, the shape of the formwork is not necessarily limited to a circle, and it may be changed as appropriate as long as it can be installed so as to surround the outer periphery of the part of the PHC pile 1 that protrudes above the ground.

[0058] According to the column-pile joint structure of each of the above embodiments, the steel column 2 and the PHC pile 1 are directly joined, eliminating the need for a foundation footing or foundation beam, thereby reducing the amount of excavated soil and the amount of steel used, thereby simplifying the structure and reducing costs.

[0059] Furthermore, the outer dimensions of the anchor pipe 23 attached to the lower end of the steel column 2 are smaller than those of the steel column 2, and the extension length of the anchor pipe 23 is set to a position higher than the upper end of the PHC pile 1, so it is not inserted into the upper end of the PHC pile 1. This increases the degree of freedom of the planar joint position of the steel column 2, reduces the amount of excavated soil, and improves the efficiency and economy of the work of joining the steel column 2 and the PHC pile 1.

[0060] The PHC pile 1 and the steel column 2 are joined by filling concrete 4 so as to cover the anchor pipe 23, the stud bolt 13, and the hoop reinforcement 14, which have outer dimensions smaller than those of the steel column 2. This makes the connection between the steel column 2 and the PHC pile 1 a semi-rigid connection, reducing the bending moment transmitted to the joint from the steel column 2 above, and improving the rationality and economy of the entire structure.

[0061] In the above embodiments, the joint structure between the PHC pile 1 and the steel column 2 has been described, but the joint structure between the column and the pile of the present invention is not limited to this. For example, the present invention can be applied to joint structures between various prefabricated piles having a hollow cross section, such as PRC piles (centrifugally formed prestressed reinforced high-strength concrete piles), SC piles (centrifugally formed concrete piles with steel shells), and steel pipe piles, and various columns having a base plate at the lower end. The joint structure between the column and the pile of the present invention can also be applied to joint structures between piles having a solid cross section, such as cast-in-place concrete piles, and various columns.

[0062] In addition, in each of the above embodiments, an example has been described in which the hoop reinforcement 14 and the reinforcing hoop reinforcement 15 are provided in three stages, but the number of stages of the hoop reinforcement 14 and the reinforcing hoop reinforcement 15 is not limited to this as long as the effect of effectively increasing the shear strength and shear resistance of the concrete 4 is exerted.

[0063] In addition, in each of the above embodiments, an example has been described in which the foundation beam of the building is omitted, but the present invention can also be applied in the same manner when a foundation beam made of steel is provided to connect the column bases of the steel column 2. [Explanation of symbols]

[0064] 1 PHC pile (pile) 11 End plate 12 Stacking Plates 13 Stud bolt 14 Hoop Muscles 15 Reinforcement hoops 16 Reinforcement band 2 Steel columns (pillars) 21 Base plate 22 Engagement part 23 Anchor Pipe 24, 25 Bearing plate 26 Stiffener 31 Construction anchor bolts 32 Construction fasteners 33, 34 Nut 4. Concrete 5 Circular throw-away formwork (throw-away formwork) 61 Crushed Stone 62 Waste concrete 7 Floor slab G. Ground

Claims

1. A joint structure between a pillar and a pile, A base plate and an anchor pipe extending downward from the base plate to a position higher than the upper end of the pile and having an outer dimension smaller than that of the column are provided at the lower end of the column, A plurality of studs are provided at the upper end of the pile so as to extend upward and surround the anchor pipe, A hoop is provided surrounding the plurality of studs from the outer periphery side, A joint structure between a pillar and a pile, in which the space from the part of the pile protruding above the ground to at least the underside of the base plate is filled with concrete so as to cover the anchor pipe, the multiple studs and the hoop reinforcement.

2. 2. The column-pile joint structure according to claim 1, wherein the hoop reinforcement is disposed in a position in contact with the stud.

3. 3. The joint structure between a column and a pile according to claim 1, further comprising a reinforcing hoop surrounding the hoop from the outer periphery.

4. 3. The column-pile joint structure according to claim 1, further comprising a stiffener for stiffening the space between the base plate and the anchor pipe.

5. 3. A column-pile joint structure according to claim 1, wherein an engagement portion is provided on the underside of the base plate for engaging with the concrete.

6. A plurality of construction anchor bolts are provided, which are installed on the ground or fixed to the upper ends of the piles so as to surround the portions of the piles that protrude above the ground; The base plate is provided with a construction fastening portion, 3. The joint structure for a column and a pile according to claim 1, wherein the column is positioned relative to the pile by fastening the construction fastening portion to the construction anchor bolt.

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