Pillar-pile joint structure

Abstract

To provide a junction structure for a column and a pile, which can simplify a structure and reduce cost by eliminating the necessity of a footing and a footing beam to reduce a drilled soil volume and a used steel frame amount, and increase rationality and profitability by setting a junction form to be semi-rigid junction to reduce a flexure force generated in a junction part.SOLUTION: A junction structure for a column and a pile having a hollow cross section is configured such that a base plate and a shear key having an outer size smaller than the column and extending below from the base plate to be inserted into an upper end of the pile are provided at a lower end of the column, a plurality of studs extending upward from a pile body so as to surround the shear key are provided at the upper end of the pile, a hoop reinforcement is provided so as to surround the plurality of studs from an outer peripheral side, and a space from the upper end of the pile to a lower surface of the base plate is filled with concrete so as to cover the periphery of the shear key, the plurality of studs, and the hoop reinforcement.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a joint structure between a column and a pile having a hollow cross section. [Background technology]

[0002] A commonly used method for connecting piles to superstructures is to connect them via reinforced concrete foundation footings or foundation beams, but this method requires complicated reinforcement work and increases the amount of soil excavated from the ground, which hinders efforts to reduce costs and shorten construction periods.

[0003] Therefore, in order to eliminate the need for foundation footings and foundation beams and reduce the amount of excavated soil, Patent Document 1, for example, discloses a column-pile joint structure and construction method in which a pile head joint metal is fixed to the pile head and fastened to the base plate of the column base to join the pile head and column base. In this method, the column base is extended below the base plate, inserted into the hollow part of the pile head, and fixed with concrete, thereby ensuring a strong, reliable, and easy joint between the column and pile. In addition, it is easy to adjust the column level and correct any misalignment of the pile.

[0004] Patent Document 2 also discloses a joining structure and method for connecting a pile to a superstructure, in which a cap steel pipe (joining jig) consisting of a base plate joined to the base of a steel column or a concrete-filled steel pipe column and a steel pipe joined to the underside of the base plate is placed over the head of a steel pipe pile or a precast concrete pile, and concrete is filled into the gap to integrate the column and pile, thereby forming a rigid joint. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-295286 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-009438 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the joint structure disclosed in Patent Document 1, in order to ensure the anchorage strength between the column and the pile and to rigidly join them, it is necessary to provide a stud on the column base extension that is inserted into the hollow part of the pile head. Furthermore, the shape of the pile head joint hardware that is fixed to the pile head is complex, and its manufacture is time-consuming. Furthermore, when inserting the column base into the hollow part of the pile head and erecting the column, the column needs to be temporarily supported with wire.

[0007] Furthermore, in the joint structure disclosed in Patent Document 2, in order to rigidly join the column and pile, the diameter of the cap steel pipe must be approximately the pile diameter + 300 mm, and the embedded length of the pile into the cap steel pipe must be approximately 1.5 times the pile diameter or more. Therefore, as the pile diameter increases, the diameter and height of the cap steel pipe that covers the pile also increase, resulting in a large amount of excavated soil and requiring more effort to transport the cap steel pipe to the site.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a column-to-pile joint structure that eliminates the need for footings and foundation beams, reduces the amount of excavated soil and steel used, simplifies the structure and reduces costs, and uses a semi-rigid joint between the column and the pile rather than a rigid joint as in Patent Document 1 or Patent Document 2, thereby reducing the bending moment transmitted from the upper column to the joint, thereby improving rationality and economy. [Means for solving the problem]

[0009] The means for solving the above problems are as follows. [1] A joint structure between a column and a pile having a hollow cross section, wherein the lower end of the column is provided with a base plate and a shear key having outer dimensions smaller than that of the column, extending downward from the base plate and inserted into the upper end of the pile, and the upper end of the pile is provided with a plurality of studs extending upward from the pile body to surround the shear key, and hoops are provided to surround the plurality of studs from the outer periphery, and the space from the upper end of the pile to the underside of the base plate is filled with concrete to cover the periphery of the shear key, the plurality of studs, and the hoops. [2] The joint structure between a column and a pile described in [1], wherein the hoop reinforcement is arranged in a position in contact with the stud. [3] A joint structure between a column and a pile described in [1] or [2], in which reinforcing hoops are provided to further surround the hoops from the outer periphery. [4] The shear key is provided with a bearing plate that protrudes laterally, and the upper end of the pile is provided with a protrusion that protrudes inward beyond the inner surface of the pile. This is a joint structure between a column and a pile described in [1] or [2]. [5] A joint structure between a pillar and a pile described in [4], wherein the stud is a bolt, and the protrusion is a reinforcing plate fastened to an end plate provided at the upper end of the pile by the bolt. [6] A column-pile joint structure according to [1] or [2], in which a stiffener is provided to stiffen the space between the base plate and the shear key. [7] A joint structure between a pillar and a pile described in [1] or [2], wherein an engagement portion that engages with the concrete is provided on the underside of the base plate. [8] A joint structure between a pillar and a pile described in [1] or [2], in which a plurality of erection anchor bolts are installed on the ground so as to surround the upper end of the pile or are fixed to the upper end of the pile, and the base plate is provided with erection fastening parts, and the pillar is positioned relative to the pile by fastening the erection fastening parts to the erection anchor bolts. [Effects of the Invention]

[0010] The column-pile joint structure of the present invention eliminates the need for footings and foundation beams, thereby simplifying the structure and reducing costs by reducing the amount of excavated soil and the amount of steel used. Furthermore, the concrete filled in the space from the top of the pile to the underside of the base plate is shear-reinforced by multiple studs extending upward from the pile body to surround the shear key, and hoops surrounding these studs from the outer periphery. This increases the shear strength and shear resistance of the concrete, resulting in a joint structure that can withstand large shear forces. Furthermore, by adjusting the joint configuration to a semi-rigid joint, the bending moment transmitted from the upper column to the joint can be reduced, further improving rationality and economy.

[0011] Furthermore, since the outer dimensions of the shear key are smaller than the outer dimensions of the column, it is easier to accommodate eccentricity of the column relative to the pile, thereby increasing design freedom and workability. [Brief explanation of the drawings]

[0012] [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. [Figure 2] 2(a) and 2(b) are a longitudinal sectional view and a plan view showing an example of a joint structure between a pillar and a pile according to the present invention. [Figure 3] FIG. 3 is a vertical cross-sectional view showing another example of the 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 according to the present invention. [Figure 5] FIG. 5 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 6] FIG. 6 is a vertical cross-sectional view showing yet 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 according to the present invention. [Figure 8]8(a) and 8(b) are a plan view and a longitudinal sectional view showing the construction procedure 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 longitudinal sectional view showing the construction procedure of the joint structure between a pillar and a pile according to the present invention. [Figure 10] 10(a) and 10(b) are a plan view and a longitudinal sectional view showing the construction procedure of 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 longitudinal sectional view showing the construction procedure of the joint structure between a pillar and a pile according to the present invention. [Figure 12] 12(a) and 12(b) are a plan view and a longitudinal sectional view showing the construction procedure of the joint structure between a pillar and a pile according to the present invention. [Figure 13] 13(a) and 13(b) are a plan view and a longitudinal sectional view showing the construction procedure of the joint structure between a pillar and a pile according to the present invention. [Figure 14] 14(a) and 14(b) are a plan view and a longitudinal sectional view showing the construction procedure of the joint structure between a pillar and a pile of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the joint structure between a pillar and a pile of the present invention will be specifically described with reference to the drawings. <Column and pile joint structure> [First embodiment] Fig. 1 shows a perspective view of a building to which a column-pile joint structure according to a first embodiment of the present invention is applied. Fig. 2(a) and Fig. 2(b) show a longitudinal section and a plan view of the column-pile joint structure according to the first embodiment.

[0014] As shown in Fig. 1, the column-pile joint structure of the first embodiment is used at the 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 with a hollow cross section. As shown in Fig. 1, no foundation beams or footings are provided at the column bases of the steel columns 2 of this steel-framed building, and the PHC piles 1 are directly joined to each column base of the steel columns 2.

[0015] Specifically, as shown in Figures 2(a) and 2(b), pre-boring is performed within the excavated part of the ground G, and a foot hardening liquid (not shown) and a pile periphery fixing liquid 10 are injected, and then the PHC pile 1 is sunk and erected so that its top 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 then concrete 62 is poured.

[0016] Meanwhile, the lower end of the steel column 2 is provided with a base plate 21 and a shear key 23 with smaller outer dimensions than the steel column 2. The shear key 23 extends downward from the base plate 21 and is inserted into the upper end of the PHC pile 1, which has a hollow cross section. In the column-pile joint structure of this embodiment, the shear key 23 is made of a seamless steel pipe, making it applicable to locations requiring high strength and bearing capacity. However, the shear key 23 may be made of other steel pipes, shaped steel, or the like. Furthermore, when the column-pile joint structure of this embodiment is used for a column base to which a brace is not attached, the shear key 23 may be made of a large-diameter reinforcing bar or other steel bar to reduce the bending rigidity of the joint between the PHC pile 1 and the steel column 2. This reduces the bending moment generated at the pile head of the PHC pile 1 and the column base of the steel column 2, resulting in a more rational structure.

[0017] 2(a) and 2(b), a bearing plate 24 is provided at the lower end of the shear key 23, protruding laterally from the shear key 23. In addition, a stiffener 26 is provided between the base plate 21 and the shear key 23 to stiffen the space between them, thereby increasing the strength and rigidity of the base plate 21.

[0018] As shown in Figures 2(a) and 2(b), a plurality of stud bolts 13 are provided on a ring-shaped end plate 11 at the upper end of the PHC pile 1, surrounding the shear key 23 and extending upward from the pile body. Each stud bolt 13 is screwed into a threaded hole provided in the end plate 11 at the upper end of the PHC pile 1. Furthermore, a protrusion that protrudes inward from the inner surface of the PHC pile 1 is provided on the ring-shaped end plate 11 at the upper end of the PHC pile 1. The protrusion is formed by a reinforcing plate 12 made of a steel plate with a thickness of, for example, 25 mm. The reinforcing plate 12 has bolt holes (not shown) at positions corresponding to the threaded holes provided in the end plate 11 of the PHC pile 1. The reinforcing plate 12 is fastened to the end plate 11 at the upper end of the PHC pile 1 by inserting the stud bolts 13 into the bolt holes and screwing nuts 14 onto them. Alternatively, instead of the above-described structure, studs such as deformed steel bars or bolts may be prepared and joined in advance to the upper surface of the reinforcing plate 12 by welding or the like, and then fastened to the end plate 11 at the upper end of the PHC pile 1.

[0019] As a protrusion that protrudes inward from the inner surface of the PHC pile 1, a horizontal rib (not shown) may be formed on the inner surface of the upper end of the PHC pile 1 instead of or in addition to the reinforcing plate 12. By providing the reinforcing plate 12 or horizontal rib, a joint structure that can withstand greater tensile and shear forces is obtained. This is because when an axial tensile force acts from the steel column 2 to the PHC pile 1, a concrete strut is formed between the steel column 2 and the bearing plate 24 provided at the lower end of the shear key 23.

[0020] In this embodiment, the inner surface of the upper end of the PHC pile 1 may be roughened by ultra-high pressure cleaning or the like. In this way, when an axial tensile force acts on the PHC pile 1 from the steel column 2, the frictional resistance against pull-out is further increased.

[0021] Furthermore, as shown in Figures 2(a) and 2(b), three rows of hoops 15 are provided on the outer periphery of the multiple stud bolts 13 extending upward from the upper end of the PHC pile 1, surrounding the multiple stud bolts 13 from the outer periphery. Each hoop 15 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 binding wire, spot welding, or the like. Three rows of reinforcing hoops 16 are provided so as to further surround the hoops 15 of each row from the outer periphery. The reinforcing hoops 16 are fixed by dice (not shown) or the like placed on the basing concrete 62. The hoops 15 and reinforcing hoops 16 are provided with a strength of, for example, 785 N / mm 2 grade (yield strength is 785N / mm 2 It is preferable to use high-strength welded closed hoop reinforcements such as reinforcing bars (reinforcing bars specified as above) because this effectively increases the shear strength and shear resistance of the concrete 4 described below.

[0022] 2(a) and 2(b), concrete 4 is filled in the space from the upper end of the PHC pile 1 to the underside of the base plate 21, covering the shear keys 23, stud bolts 13, hoops 15, and reinforcing hoops 16. In this way, the PHC pile 1 and the steel column 2 are joined.

[0023] In the column-pile joint structure of this embodiment, multiple erection anchor bolts 31 are provided on the base concrete 62 in the excavated portion of the ground G so as to surround the upper end of the PHC pile 1. In addition, an erection 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 erection fastening portion 32 is formed, for example, by combining two 40 mm thick steel plates, and has a bolt hole (not shown) at a position corresponding to the erection anchor bolt 31. The erection fastening portion 32 is fastened to the erection anchor bolt 31 by screwing a nut 33 onto the erection anchor bolt 31 that protrudes above the erection fastening portion 32 from the bolt hole. This allows the steel column 2 to be positioned relative to the PHC pile 1.

[0024] A floor slab (not shown) may be provided around the base of the steel column 2 as needed.

[0025] In this embodiment, the bearing plate 24, reinforcing plate 12, and horizontal rib are not necessarily required, and may be omitted, for example, when the steel column 2 is provided in a location where a large pull-out force is not applied. By providing the bearing plate 24, reinforcing plate 12, and horizontal rib as in this embodiment, a joint structure that can withstand a larger axial tensile force is obtained. This is because, when an axial tensile force acts from the steel column 2 to the PHC pile 1, a concrete strut is formed between the bearing plate 24 provided at the lower end of the shear key 23.

[0026] In addition, in this embodiment, the stiffener 26 is not necessarily required, but it is preferable to provide the stiffener 26 as in this embodiment, if necessary, to adjust the joint form between the column and the pile to a semi-rigid joint and increase the strength and rigidity of the base plate 21. [Second embodiment] FIG. 3 shows a vertical cross-sectional view of a joint structure between a pillar and a pile according to a second embodiment of the present invention.

[0027] As shown in Fig. 3, the joint structure between a column and a pile of this embodiment does not have the stiffener 26 in the joint structure between a column and a pile of the first embodiment. In other respects, the joint structure between a column and a pile of this embodiment is configured in the same way as the joint structure between a column and a pile of the first embodiment.

[0028] In this embodiment, by omitting the stiffener 26 that stiffens the space between the base plate 21 and the shear key 23, the joint rigidity between the column and the pile can be adjusted to be lower, 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, sufficient plastic deformation capacity can be ensured. [Third embodiment] FIG. 4 shows a vertical cross-sectional view of a joint structure between a pillar and a pile according to a third embodiment of the present invention.

[0029] As shown in Figure 4, in the joint structure between a pillar and a pile of this embodiment, in addition to the support plate 24 that is provided at the lower end of the shear key 23 in the joint structure between a pillar and a pile of the second embodiment and protrudes laterally, a support plate 25 that protrudes laterally from the shear key 23 is also provided at the middle part of the shear key 23.

[0030] In other respects, the joint structure between a pillar and a pile in this embodiment is configured in the same manner as the joint structure between a pillar and a pile in the second embodiment.

[0031] As in this embodiment, by providing bearing plates that protrude laterally from the shear key 23 at multiple locations, a joining structure that can withstand even greater axial tensile force is obtained. [Fourth embodiment] FIG. 5 shows a vertical cross-sectional view of a joint structure between a pillar and a pile according to a fourth embodiment of the present invention.

[0032] As shown in Figure 5, in the column-pile joint structure of this 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 second embodiment. For the engagement portion 22, for example, a flat bar measuring approximately 25 mm x 32 mm x 450 mm can be used.

[0033] In other respects, the joint structure between a pillar and a pile in this embodiment is configured in the same manner as the joint structure between a pillar and a pile in the second embodiment.

[0034] In this 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 portion of the inner surface of the upper end of the PHC pile 1. [Fifth embodiment] FIG. 6 shows a vertical cross-sectional view of a joint structure between a pillar and a pile according to a fifth embodiment of the present invention.

[0035] 6, in the joint structure between a pillar and a pile of this embodiment, a reinforcing band 17 is wound around the outer periphery of the upper end of the PHC pile 1 in the joint structure between a pillar and a pile of the fourth embodiment. The reinforcing band 17 can be formed by winding a wire made of steel plate, steel wire, carbon fiber, or the like around the outer periphery of the upper end of the PHC pile 1.

[0036] In other respects, the joint structure between a pillar and a pile in this embodiment is configured in the same manner as the joint structure between a pillar and a pile in the fourth embodiment.

[0037] In this embodiment, a reinforcing band 17 is wrapped around the outer periphery of the upper end of the PHC pile 1, and by resisting the circumferential stress of the PHC pile, the resistance to loads acting horizontally on the inner surface of the upper end of the PHC pile 1 is increased, resulting in a joint structure that can withstand even larger shear forces and bending moments at the column base. [Sixth embodiment] FIG. 7 shows a vertical cross-sectional view of a joint structure between a pillar and a pile according to a sixth embodiment of the present invention.

[0038] As shown in Figure 7, in the column-pile joint structure of this embodiment, the erection anchor bolts 31 in the column-pile joint structure of the first embodiment are provided not on the basin concrete 62 but on the outer peripheral extensions of the reinforcing plate 12 provided at the upper end of the PHC pile 1, and are fastened with nuts 34. Then, the erection fastening parts 32 welded to the side edges of the base plate 21 of the PHC pile 1 are fastened with nuts 33 to the erection anchor bolts 31, thereby positioning the steel column 2 with respect to the PHC pile 1.

[0039] In other respects, the joint structure between a pillar and a pile in this embodiment is configured in the same manner as the joint structure between a pillar and a pile in the first embodiment.

[0040] In the column-pile joint structure of each of the above embodiments, the strength and rigidity of the column-pile joint structure can be adjusted to the desired level 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 engaging portion 22, the diameter and thickness of the shear key 23, the plate thickness, protruding width, number, and arrangement of the bearing plates 24 and 25, the plate thickness, number, and arrangement of the stiffener 26, the plate thickness and protruding width of the reinforcing plate 12, and the insertion depth into the upper end of the PHC pile 1 can be adjusted. This allows the compressive strength, tensile strength, bending strength, shear strength, compressive rigidity, tensile rigidity, bending rigidity, and shear rigidity of the column-pile joint structure to be adjusted.

[0041] By making such adjustments, for example, if the joint structure between a column and a pile is made semi-rigid, the bending force generated at the joint is reduced, making it possible to economically design the entire joint structure.

[0042] Furthermore, for example, when braces are installed between steel columns 2, large axial tensile forces are likely to act between the PHC pile 1 and the steel columns 2, so it is preferable to set the thickness and other dimensions of the base plate 21 so that it can withstand this large axial tensile force. <Construction method for connecting pillars and piles> 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 Figures 8 to 14. Below, construction of the joint structure between a pillar and a pile in the second embodiment will be described.

[0043] First, as shown in the plan view of Figure 8(a) and the longitudinal cross section of Figure 8(b), the ground G is excavated, pre-bored within the excavation, and a foot-hardening fluid (not shown) and a pile-periphery fixing fluid 10 are injected. The PHC pile 1 is then sunk and erected. The pile-periphery fixing fluid 10 protects the borehole wall during erection of the PHC pile 1 and fills the gap between the borehole wall and the PHC pile 1 to ensure adhesion to the surrounding ground. When the PHC pile 1 is sunk into the borehole, the pile-periphery fixing fluid 10 also flows into the hollow portion of the PHC pile 1. A ring-shaped end plate 11 is attached to the upper end of the PHC pile 1. At this time, the upper end of the PHC pile 1 (e.g., a portion approximately 300 mm from the top of the PHC pile 1) is set to protrude from the surface of the ground G at the excavation area.

[0044] Then, the pile surrounding fixing liquid 10 that has solidified inside the PHC pile 1 is removed, for example, by scooping, to a depth of about 800 mm from the top of the PHC pile 1, and space is secured within the upper end of the PHC pile 1 for inserting the shear key 23 of the steel column 2.

[0045] Alternatively, when the PHC pile 1 is sunk into the borehole, a spacer (not shown) may be attached inside the PHC pile 1. After the PHC pile 1 is sunk, the spacer may be pulled out before the fixative liquid 10 around the pile solidifies, thereby lowering the liquid level of the fixative liquid 10 around the pile by the volume of the spacer and securing a space for inserting the shear key 23 of the steel column 2.

[0046] When erecting the PHC pile 1 into the ground G, it is not necessary to use the pile surrounding fixing liquid 10; it is sufficient to ensure that space is secured within the upper end of the PHC pile 1 after the PHC pile 1 has been erected to insert the shear key 23 of the steel column 2.

[0047] Next, as shown in the plan view of FIG. 9(a) and the longitudinal cross-sectional view of FIG. 9(b), a reinforcing plate 12 is installed on a ring-shaped end plate 11 installed at the upper end of the PHC pile 1 so as to protrude inward from the inner surface of the PHC pile 1. At this time, the positions of the bolt holes in the reinforcing plate 12 are aligned with the positions of the screw holes in the end plate 11 of the PHC pile 1. Then, stud bolts 13 are screwed into each screw hole in the end plate 11 of the PHC pile 1. This results in multiple stud bolts 13 extending upward from the pile body so as to surround the shear key 23. Then, nuts 14 are screwed onto the stud bolts 13 inserted into the bolt holes in the reinforcing plate 12, and the reinforcing plate 12 is fastened to the end plate 11 at the upper end of the PHC pile 1.

[0048] Next, as shown in the plan view of Figure 10(a) and the longitudinal cross section of Figure 10(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 basal concrete 62 is poured. At this time, a plurality of erection anchor bolts 31 are placed on the ground G so as to surround the upper end of the PHC pile 1 installed in the ground G, and are fixed to the basal concrete 62 in the excavated portion of the ground G.

[0049] As shown in Figures 10(a) and 10(b), depending on the design of the building, the conditions of the construction site, etc., the reference axes for the arrangement of the multiple erection 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. In this case, the column core position on the basing concrete 62 is marked out, and the reference axes for the arrangement of the multiple erection anchor bolts 31 are aligned with this marking and fixed to the basing concrete 62. The erection anchor bolt 31 is provided to temporarily support a section of the column base of the steel column 2 in order to position the steel column 2 relative to the PHC pile 1.

[0050] Next, as shown in the plan view of Figure 11(a) and the longitudinal cross section of Figure 11(b), hoops 15 are installed around the periphery of the multiple stud bolts 13 extending upward from the top end of the PHC pile 1, surrounding these multiple stud bolts 13 from the periphery. At this time, each hoop 15 is placed so as to be in contact with the stud bolt 13, and fastened to the stud bolt 13 with a tie wire, spot welding, or the like. Furthermore, reinforcing hoops 16 are installed on the basing concrete 62 using a die (not shown) or the like, so as to further surround the hoops 15 from the periphery.

[0051] Next, as shown in the plan view of FIG. 12(a) and the longitudinal cross-sectional view of FIG. 12(b), an erection fastening portion 32 made of a steel plate 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 so that the shear key 23 of the steel column 2 is inserted into the upper end of the PHC pile 1 to a depth of, for example, about 500 mm from the top of the PHC pile 1. At this time, the erection anchor bolts 31 are inserted into the bolt holes provided in the erection anchor bolts 31. Then, the level of the steel column 2 is adjusted, and nuts 33 are screwed onto the erection anchor bolts 31, thereby fastening the erection fastening portion 32 to the erection anchor bolts 31 and temporarily fixing them.

[0052] Next, as shown in the plan view of FIG. 13(a) and the longitudinal cross-section of FIG. 13(b), a circular temporary formwork (temporary formwork) 5 is installed to surround the outer periphery of the upper end of the PHC pile 1. Furthermore, as shown in the plan view of FIG. 14(a) and the longitudinal cross-section of FIG. 14(b), the space from the upper end of the PHC pile 1 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 shear key 23, and then hardened. Because the interior of the PHC pile 1 is filled with the pile periphery fixative 10, it is not necessary to provide a formwork for forming the underside of the concrete 4 inside the PHC pile 1 below the shear key 23. Furthermore, as described above, it is not necessary to use the pile periphery fixative 10 when erecting the PHC pile 1 into the ground G. In this case, it is not necessary to provide a formwork for forming the underside of the concrete 4 inside the PHC pile 1; it is sufficient that the periphery of the shear key 23 is completely covered with 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 shear key 23 as needed to save the amount of concrete 4. This completes the construction of the joint structure between the column and the pile. Thereafter, if necessary, a floor slab 7 can be provided around the base of the steel column 2, as shown in Figure 14(b).

[0053] 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 upper end of the PHC pile 1.

[0054] The column-pile joint structure of each of the above embodiments eliminates the need for footings and foundation beams, thereby reducing the amount of excavated soil and the amount of steel used, simplifying the structure and reducing costs. Furthermore, the concrete 4 filled in the space from the upper end of the PHC pile 1 to the underside of the base plate 21 is shear-reinforced by multiple stud bolts 13 extending upward from the pile body to surround the shear key 23, and by hoops 15 and reinforcing hoops 16 surrounding these from the outer periphery. This increases the shear strength and shear resistance of the concrete 4, resulting in a joint structure that can withstand large shear forces. Furthermore, the semi-rigid joint reduces the bending force generated at the joint, improving rationality and economy.

[0055] Although the above embodiments have been described with respect to the joint structure between the PHC pile 1 and the steel column 2, the joint structure between a column and a pile of the present invention is not limited to this. For example, the present invention can also be applied to joint structures between various prefabricated piles with hollow cross sections, such as PRC piles (centrifugally formed prestressed reinforced high-strength concrete piles), SC piles (centrifugally formed concrete piles with outer steel pipes), and steel pipe piles, and various columns equipped with base plates at their lower ends.

[0056] Furthermore, in each of the above embodiments, an example has been described in which the hoops 15 and reinforcing hoops 16 are provided in three tiers, but the number of tiers of the hoops 15 and reinforcing hoops 16 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.

[0057] Furthermore, in each of the above embodiments, examples have been described in which the foundation beams of the building are omitted, but the present invention can also be applied in the same way when a foundation beam made of steel is provided to connect the bases of the steel columns. [Explanation of symbols]

[0058] 1 PHC pile (pile) 10 Pile circumference fixative 11 End plate 12 Reinforcement plate (protrusion) 13 Stud bolt 14 Nut 15 Hoop Muscle 16 Reinforcing hoops 17 Reinforcement band 2 Steel columns (pillars) 21 Base Plate 22 Engagement portion 23 Shiaki 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 Concrete 7 Floor slab G Ground

Claims

1. A joint structure between a column and a pile having a hollow cross section, A base plate and a shear key having an outer dimension smaller than that of the column are provided at the lower end of the column, extending downward from the base plate and inserted into the upper end of the pile. A plurality of studs extending upward from the pile body so as to surround the shear key are provided at the upper end of the pile, A hoop is provided surrounding the plurality of studs from the outer periphery, A column-pile joint structure in which concrete is filled in the space from the upper end of the pile to the lower surface of the base plate so as to cover the shear key, the plurality of 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 of claim 1, further comprising a reinforcing hoop surrounding the hoop from the outer periphery.

4. The shear key is provided with a bearing plate that protrudes laterally, 3. The joint structure for a pillar and a pile according to claim 1, wherein a protrusion is provided at the upper end of the pile, the protrusion protruding inward beyond the inner surface of the pile.

5. The stud comprises a bolt, 5. The joint structure for a pillar and a pile according to claim 4, wherein the protrusion comprises a reinforcing plate fastened to an end plate provided at the upper end of the pile by the bolt.

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

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

8. A plurality of erection anchor bolts are provided, which are installed on the ground so as to surround the upper end of the pile or fixed to the upper end of the pile, The base plate is provided with an erection fastening portion, 3. The joint structure between a column and a pile according to claim 1, wherein the column is positioned relative to the pile by fastening the erection fastening portion to the erection anchor bolt.

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