Upper pile and lower pile connection structure

Abstract

To efficiently resist against shear force generated in a connection structure that a lower pile 10 and an upper pile 30 composed of precast concrete piles are connected to each other, and reduce drawing force generated in a bolt.SOLUTION: A connection structure 70 is configured that a lower pile 10 and an upper pile 30 are overlapped above and below, steel side plates 15 and 15A and steel end plates 25 and 25A are brought into close contact with each other, a connection plate 40 is fit to the outer peripheral side and covers it, and the connection plate 40 is bound by bolts 71. An end face 17 of the steel end plate 15 of the lower pile 10 and an end face 26 of the steel end plate 25 are formed in a deviated manner, and steps 61 are formed with a distance H0 in a vertical direction. The corresponding step 61 is also formed in the upper pile 30. First connection protruded strips 47 and 51 provided at right angles are formed on the upper and lower sides of an inner surface 42 of the connection plate 40, and are fit to first connection recessed strips 18 and 18A and second connection recessed strips 19 and 19A of the upper and lower piles 10 and 30.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a connecting structure for an upper pile and a lower pile, which are joined by a connecting tool in order to embed a standard pile into a deeper pile hole.

Background Art

[0002] Normally, a precast concrete pile has a length of about 10 m, and may be embedded in a pile hole deeper than 20 m and exceeding 50 m. In this case, it was necessary to connect a plurality of precast concrete piles. In this case, the steel end plate of the upper pile and the steel end plate of the lower pile are abutted (this abutting surface is defined as the end plate close contact surface 64), and it was necessary to reinforce with a connecting member that covers the end plate close contact surface 64 from the outer peripheral side. For example, in Patent Documents 1 and 2, a connecting structure is formed in which a connecting member divided in the circumferential direction is placed on the outer peripheral side of the end plate close contact surface 64, and the connecting member is fixed to the upper and lower piles with bolts.

Prior Art Documents

Patent Documents

[0006] In other words, this invention is a connecting structure for an upper and lower pile, characterized in that a donut-shaped steel end plate is provided on the longitudinal end face of a concrete pile body, and a short cylindrical steel side plate covering the outer wall of the pile body is connected to the steel end plate to form an upper and lower pile, the upper and lower piles are connected by joining the steel end plates, and the inner surface of a partially annular connecting plate is tightly fastened to the outer surface of the steel side plate, as described below. (1) The steel end plates of the upper pile and the lower pile are brought into contact with each other at the end plate contact surfaces, and the steel side plates of the upper pile and the lower pile are brought into contact with each other at the side plate contact surfaces. (2) With respect to the horizontal plane between the end plate contact surface and the side plate contact surface Approximately right angle A step is formed Ta. (3) The connecting plate is connected to the steel side plate by bolts that pass through bolt holes in the connecting plate. (4) The thickness of the connecting plate near the bolt through-hole is T, and on the inner surface of the plate body, which is made by bending a flat plate of thickness T into an arc shape in plan view, a first connecting protrusion of height t1 and a second connecting protrusion of height t2 are provided in series from the side closest to the side plate contact surface, on the upper pile side and the lower pile side, respectively, with heights t1 and t2 being the heights from the inner surface of the plate body. (5) On the lower pile side, the distance from the side plate contact surface to the upper edge of the first connecting ridge is h01, and the distance from the lower edge of the first connecting ridge to the upper edge of the second connecting ridge is h12 Let's assume that. On the upper pile side, the distance from the side plate contact surface to one lower edge of the first connecting ridge is defined as h01, and the distance from the other upper edge of the first connecting ridge to one lower edge of the second connecting ridge is defined as h2. h01=h1, h12=h2 It was formed by [this method]. (6) The outer surface of the steel end plate of the upper pile and the outer surface of the steel side plate of the lower pile are formed with a first connecting recess and a second connecting recess, respectively, into which the first connecting protrusion and the second connecting protrusion can be fitted. (7) The horizontal edges of the first connecting protrusion and the horizontal edges of the second connecting protrusion are formed perpendicular to the inner surface of the connecting plate. (8) The thickness T of the connecting plate body is A ≤T ≤ (h1 + h2) ÷ (√3) and B ≤ T ≤ (t1 + t2) That's what I decided. A and B mentioned above are, The tensile force acting on the bolt generates The thickness of the connecting plate that can withstand shear force This is the minimum value. [Effects of the Invention]

[0007] In this invention, a step is formed between the end plate contact surface and the side plate contact surface on the upper surface of the lower pile and the lower surface of the upper pile, or a step is formed within the side plate contact surface, with respect to the horizontal plane, so that it can effectively resist excessive shear force generated in the upper and lower piles. Furthermore, a first connecting protrusion and a second connecting protrusion are formed on the upper and lower pile sides of the connecting plate, respectively, perpendicular to the inner surface of the plate body with thickness T, and the height t of both connecting protrusions from the inner surface of the plate body and the vertical distance h are (√3)T≦(h1+h2) and T ≤ (t1 + t2) In this case, the pull-out force generated in the bolts that tightly connect the connecting plate and the steel side plates of the upper and lower piles can be reduced. Furthermore, the thickness T of the plate body of the connecting plate can be made thinner depending on the amount of pull-out force that can be reduced. [Brief explanation of the drawing]

[0008] [Figure 1] This shows a vertical cross-sectional view of the first connecting structure of this invention after the connection has been completed. [Figure 2] This diagram shows a longitudinal cross-sectional view of the upper pile, lower pile, and connecting plate before connection, representing the first connecting structure of this invention. [Figure 3] The first connection structure of the present invention, showing an enlarged longitudinal sectional view of the connection plate. [Figure 4] The connection structure of the present invention, showing a schematic cross-sectional view of the arrangement of the connection plate and the bolts. [Figure 5] A perspective view schematically showing the first connection structure of the present invention, where (a) shows the upper pile and the lower pile before contact, (b) shows the upper pile and the lower pile in contact, and (c) shows the state where the connection plate is covered and the bolts are screwed in to complete the connection. [Figure 6] (a) is a longitudinal sectional view explaining the outline of the shear force generated in the first connection structure of the present invention, and (b) is a partially enlarged longitudinal sectional view on the upper pile side. [Figure 7] The second connection structure of the present invention, showing a longitudinal sectional view after the connection is completed. [Figure 8] The third connection structure of the present invention, showing a longitudinal sectional view after the connection is completed.

Embodiments for Carrying Out the Invention

[0009] 1. The first connection structure 70

[0010] The connection structure 70 of the present invention is composed of a lower pile 10, an upper pile 30, a connection plate 40, and bolts 71. Here, the lower pile 10 is a concrete pile with PC steel bars 33 embedded therein, and the upper pile 30 is a concrete pile with its outer periphery covered with a steel pipe 35. However, as long as it is a concrete-based pile provided with a steel end plate 25 and a steel side plate 15, the type of the pile to be connected can be arbitrary.

[0011] (1) Structures of the lower pile 10 and the upper pile 30

[0012] The lower pile 10 is a cylindrical pile body 11 made of concrete with a hollow section 11a. It has donut-shaped steel end plates 25 at both ends 12, 12a (not shown) along its length, and a cylindrical steel side plate 15 connected to the base end 26a (opposite the end 26 (pile body 11 side)) of the steel end plate 25. Figure 2 shows a PC steel bar that is locked between the two steel end plates 25, 25 and introduces prestress to the pile body 11. Figure 2 shows a reinforcing band made of a short steel pipe connected to the base end 26a of the steel side plate 15, which protects both ends of the pile body 11. At the joint surface between the steel end plate 25 and the steel side plate 15, the tip surface 17 (upper end in Figure 2) of the steel side plate 15 is lowered (raising the tip surface 26 of the steel end plate 25), creating a step 61 with a distance H0 between the tip surface 17 of the steel side plate 25 and the tip surface 17 of the steel side plate 15. In other words, the outer peripheral surface 27 of the steel end plate 25 of the lower pile 10 and the inner surface 16Aa of the steel side plate 15A of the upper pile 30 are in close contact, forming a step 61 (Figures 1 and 2).

[0013] Furthermore, the upper pile 30 is formed with the same outer diameter as the lower pile 10 and is a cylindrical pile body 11A made of concrete with a hollow section 11Aa. It is equipped with donut-shaped steel end plates 25A at both ends 12A, 12Aa (not shown) in the longitudinal direction, and a cylindrical steel side plate 15A connected to the base end 26Aa (opposite the end A26 (pile body 11A side)) of the steel end plate 25A. In the figure, 35 is a covering steel pipe connected to the base ends 26Aa of both steel side plates 15A, 15A, covering the entire side surface of the pile body 11A. At the joint surface between the steel end plate 25A and the steel side plate 15A, the leading edge 17A (lower end in Figure 2) of the steel side plate 15A is lowered (raising the leading edge 26A of the steel end plate 25A), creating a step 61 with a distance H0 between the leading edge 17A of the steel side plate 25A and the leading edge 17A of the steel side plate 15A.

[0014] Furthermore, when the upper pile 30 is placed on the lower pile 10 and connected, the tip surface 26 (upper end surface in the figure) of the steel end plate 25 of the lower pile 10 and the tip surface 26A (lower end surface in the figure) of the steel end plate 25A of the upper pile 30 come into contact, and this surface becomes the end plate contact surface 64. Similarly, the tip surface 17 (upper end surface in the figure) of the steel side plate 15 of the lower pile 10 and the tip surface 17A (lower end surface in the figure) of the steel side plate 25A of the upper pile 30 come into contact, and this surface becomes the side plate contact surface 63 (Figure 2). Furthermore, the step 61 (i.e., the outer circumferential surface 27 of the steel end plate 25 and the inner surface 16Aa of the steel side plate 15A) is formed perpendicular to the side plate contact surface 63 and the end plate contact surface 64 (Figures 1 and 2). Alternatively, the step 61 can be described as a structure where the side plate contact surface 63 and the end plate contact surface 64 are not in a straight line, but rather have a step.

[0015] (2) Structure of connecting plate 40, detailed structure of steel side plates 15, 15A

[0016] (a) A flat plate with thickness T and width h00 (height in the figure) is bent to form a plate body 41 that is arc-shaped (partially annular) in plan view. When three plate bodies 41 are arranged in an annular shape, it forms an annular shape, and the inner surfaces of the plate bodies 41 coincide with the outer surfaces of the steel side plates 15 and 15A of the upper and lower piles 10 and 30 (outer surfaces of the upper and lower piles 10 and 30). Furthermore, when the upper and lower piles 10 and 30 are connected, the plate body 41 is formed so that the height position of the side plate contact surface 63 of the upper and lower piles 10 and 30 is located in the center of the plate body 41, and the position of the side plate contact surface 63 is defined as the center line 44 of the plate body 41. In Figure 2, the lower side of the center line 44 is the side that connects to the steel side plate 15 of the lower pile 10, and the upper side of the center line 44 is the side that connects to the steel side plate 15A of the upper pile 30 (Figure 3). Furthermore, the inner side of the arc shape of the plate body 41 in plan view (towards the upper and lower piles 10 and 30) is designated as the inner surface 42, and the opposite outer side is designated as the outer surface 42a (Figures 3 and 4).

[0017] (b) On the inner surface 42 of the plate body 41, a first connecting protrusion 46 and a second connecting protrusion 51 are provided projecting from the center line 44 toward the lower end 43a (the side corresponding to the steel side plate 15 of the lower pile 10), and bolt holes 55 are formed. Similarly, on the inner surface 42 of the plate body 41, a first connecting protrusion 46 and a second connecting protrusion 51 are provided projecting from the center line 44 toward the upper end 43 (the side corresponding to the steel side plate 15A of the upper pile 30), and bolt holes 55 are formed. Here, the side edges of the first connecting ridge 46, one side edge 48 (towards the center line 44) and the other side edge 48a (towards the center line 44), and the side edges of the second connecting ridge 51, one side edge 53 (towards the center line 44) and the other side edge 53a (towards the center line 44), are formed at approximately right angles to the inner surface 42 of the plate body 41 (Figure 3).

[0018] (c) Also, on the lower pile 10 side, the distance from the center line 44 to one side edge 48 (on the center line 44 side) of the first connecting protrusion 46 is h01, and the distance from the other side edge 48a (the side farther from the center line 44) of the first connecting protrusion 46 to one side edge 53 (on the center line 44 side) of the second connecting protrusion 51 is h12. Also, the distance from the other side edge 53a (the side farther from the center line 44) of the second connecting protrusion 51 to the axis of the bolt hole 55 is h23. Similarly, on the upper pile side, the distance from the center line to one side edge (lower side) of the first connecting protrusion is defined as h01, and the distance from the other side edge (upper side) of the first connecting protrusion to one side edge (lower side) of the second connecting protrusion is defined as h12. Also, the distance from the other side edge (upper side) of the second connecting protrusion to the axial edge of the bolt hole 55 is defined as h23 (Figure 3).

[0019] (d) The connecting plate 40 is constructed as described above (Figures 3 and 2). In this embodiment, five bolts 71 are used in the circumferential direction for one connecting plate 40 (Figure 4), so five bolt holes 55, 55 are formed in two rows, upper and lower, for a total of 10 locations.

[0020] (e) Here, the first connecting protrusion 46 and the second connecting protrusion 51 are formed under the following conditions 1 and 2. <Condition 1> (Plate body thickness T = Height t1 of the first connecting protrusion + Height t2 of the second connecting protrusion) <Condition 2> (√3) × (thickness T of the plate body) = Width of the first connecting protrusion h1 + Width of the second connecting protrusion h2) Therefore, T = (√3 / 3) × (h1 + h2) This is how it is constructed. As a result, compared to conventional designs, the thickness T of the connecting plate 40 can be reduced while resisting shear forces generated in the connecting plate 40 due to external forces (bending) applied to the upper and lower piles 10 and 30.

[0021] (f) The above conditions <Condition 1> and <Condition 2> can be set within the following ranges. <Condition 1> A ≤ T ≤ (t1 + t2) <Condition 2> B≦T≦(√3 / 3)×(h1+h2) Here, a shear force is generated in the connecting plate 40 due to the tensile force acting on the bolt 71, and A and B above represent the minimum values ​​that can withstand this shear force. Also A and B are determined by factors such as the assumed external force, the tensile force generated in the bolt due to the external force, and the degree of shear force generated in the connecting plate due to the tensile force.

[0022] (g) Here, h01=h1 and h12=h2 are formed.

[0023] (h) The steel side plates 15 of the lower pile 10 and the steel side plates 15A of the upper pile 30 are formed so that they can be fitted into the connecting plate 40 constructed as described above. In other words, the steel side plate 15 and steel end plate 25 of the lower pile 10 and the steel side plate 15A and steel end plate 25A of the upper pile 30 are in close contact, forming a side plate contact surface 63 and an end plate contact surface 64. With these surfaces, the outer circumferential surface 16 of the steel side plate 15 of the lower pile 10 has a first connecting recess 18 and a second recess 19 that can accommodate the first connecting protrusion 46 and the second connecting protrusion 51 (on the lower end 43a side of the center line 44) of the connecting plate 40. Similarly, the outer circumferential surface 16A of the steel side plate 15A of the upper pile 10 has a first connecting recess 18A and a second recess 19A that can accommodate the first connecting protrusion 46 and the second connecting protrusion 51 (on the upper end 43 side of the center line 44) of the connecting plate 40 (Figure 2).

[0024] (3) Connection structure 70

[0025] A standard pile hole is excavated, and a predetermined number of concrete piles are connected, with the lower pile 10 (not shown) being connected as the second pile from the top. The connection of these concrete piles (for example, if the pile hole is about 50m long, three concrete piles about 10m long are connected) can also be done using conventional connecting plates. However, the connecting plate 40 is optimal when a large horizontal force is applied to the pile and the pile must bear a large shear load. The upper end of the lower pile 10 is supported near the pile hole, and the uppermost pile, the upper pile 30 (a concrete pile covered with a steel pipe), is connected to it.

[0026] This connecting structure 70 is generally ideal for connecting the uppermost precast pile, where large shear forces are typically generated, to the precast pile below it (the second from the top), but it can also be used to connect precast piles at any desired position.

[0027] (a) The lower pile 10 is supported near the opening of the pile hole (near the ground), and the upper pile 30 is lowered from above the lower pile 10 (Figure 5(a), Figure 2), so that the lower surface of the upper pile 30 rests on the upper surface of the lower pile 10 (Figure 5(b)). In this state, the steel side plate 15 and steel end plate 25 of the lower pile 10 and the steel side plate 15A and steel end plate 25A of the upper pile 30 are in close contact, forming a side plate contact surface 63 and an end plate contact surface 64 (see Figures 5(b) and 1).

[0028] (b) Next, the inner surfaces 42 of the three connecting plates 40, 40 are brought into close contact with the outer surfaces 16, 16A of the steel side plates 15, 15A of the upper and lower piles 10, 30, and the first connecting protrusions 46, 46 of the connecting plate 40 are fitted into the first connecting recesses 18, 18A and the second connecting recesses 19, 19A of the upper and lower piles 10, 30. Subsequently, bolts 71, 71 are screwed from the bolt holes 55, 55 of the connecting plate 40 into the threaded holes 21, 21A of the steel end plates 15, 15A of the upper and lower piles 10, 30, thereby tightly connecting the upper and lower piles 10, 30 and the connecting plates 40, 40 as a single unit. The connecting structure 70 of the upper and lower piles is thus constructed (Figures 1 and 5(c)).

[0029] (c) All connected precast piles, including the connecting structure 70 for the upper and lower piles 10 and 30, are lowered into the pile holes to construct the foundation pile structure. The pile holes are filled with cement grout between the precast piles, including the connecting structure 70 (not shown).

[0030] (d) In the connected structure 70 constructed in this manner (a structure in which the connecting plate 40 is fixed to the upper pile 10 and the lower pile 30 with bolts 71 and 17), bending stresses and shear stresses may occur in the connected structure 70 due to excessive horizontal loads that exceed expectations, in addition to the vertical loads of the above-ground structure. The vertical step difference 61 between the lower pile 10 and the upper pile 30 can withstand the shear force generated in the connecting structure 70 (Figure 1). Furthermore, since the structure is as described in Conditions 1 and 2 above, the compressive force against the axial force and bending moment generated in the connecting structure 70 is borne by the pile body 11, 11A (i.e., the pile concrete) via the tip surfaces 17, 17A of the steel side plates 15, 15A and the steel end plates 25 of the upper and lower piles 10, 30. Therefore, the connecting structure 70 of the present invention only needs to bear tensile force (Figure 6(a)(b)). Furthermore, due to the structure of conditions 1 and 2 described above, the plate body 41 of the connecting plate 40 can efficiently resist tensile force despite its thin thickness T. The upper end 43 side of the connecting plate 40 will be explained (Figure 6(b)). When an axial tensile force N is applied, the axial tensile force N is transmitted to the first connecting protrusion 46 and the second connecting protrusion 51 of the connecting plate 40 via the first connecting groove 18A and the second connecting groove 19A of the steel side plate 15A, and is resisted by the thickness T of the connecting plate 40. In other words, one side edge 48 (center line 44 side) of the first connecting protrusion 46 and one side edge 53 (center line 44 side) of the second connecting protrusion 51 are each pushed by a force of the transmitted force (N / 2). At this time, bending moments Ma and Mb are generated in the connecting plate 40 according to the eccentric distance e[(T / 2)+(t1 / 2)] and [(T / 2)+(t1 / 2)] between the point of application of the transmitted force (N / 2) and the center of the thickness T of the connecting plate 40. In the direction of separation of the connecting plate 40, shear forces due to Ma and Mb are generated, but between one side edge 48 of the first connecting rib 46 and one side edge 53 of the second connecting rib 51, the directions of the Ma and Mb forces are opposite, so the shear forces cancel each other out. That is, between one side surface 53 of the second connecting rib 51 and the bolt 71, only the shear force due to Mb is generated, and the pull-out force generated in the bolt 71 can be reduced.

[0031] (4) Other embodiments

[0032] In the above embodiment, the connecting plate 40 has a structure in which a circle is divided into three parts in plan view (i.e., three parts make up a circle), but it can also be divided into two parts or four or more parts (not shown). Furthermore, it is also possible to arrange the connecting plates 40 so that there is a small gap between them relative to the circle in plan view (not shown).

[0033] Furthermore, in the above embodiment, connecting protrusions 45 and 51 are formed on the connecting plate 40 and connecting recesses 18 and 19 are formed on the steel side plates 15 and 15A of the upper and lower piles 10 and 30. However, it is also possible to form connecting recesses on the connecting plate 40 and connecting protrusions that can fit with the connecting recesses are formed on the steel side plates 15 and 15A of the upper and lower piles 10 and 30 (not shown).

[0034] Furthermore, in the above embodiment, a first connecting projection 45 and a second connecting projection 51 were formed on the lower pile 10 side and the upper pile 30 side of the connecting plate 40, respectively. However, it is also possible to form a single connecting projection on both the lower pile 10 side and the upper pile 30 side of the connecting plate 40 (not shown).

[0035] Furthermore, in the above embodiment, the step 61 of H0 was formed by shifting the vertical positions of the side plate contact surface 63 and the end plate contact surface 63. However, it is sufficient that the side plate contact surface 63 and the end plate contact surface 63 are not on the same horizontal line and a step is formed, and the position of the step 61 is arbitrary. For example, the side plate contact surface 63 (end faces 17, 17A of the steel side plates 15, 15A) can be shifted to form a hook-shaped step 61 on the side plate contact surface 63a on the steel end plate side and a side plate contact surface 63b on the outer circumference side (see Figure 8).

[0036] 2. Second connecting structure 73 (Figure 7)

[0037] (1) The lower pile 10, like the first connecting structure 70, is equipped with a steel end plate 25, which is formed by connecting a steel side plate 15 to the tip 12 of the concrete pile body 11. The upper pile 30 is equipped with a steel end plate 25A, which is formed by connecting a steel side plate 15A to the tip 12A of the concrete pile body 11A. When the lower pile 30 is placed on top of the upper end of the upper pile 10, the tip 17 of the steel side plate 15 and the tip 17A of the steel side plate 15A overlap to form a side plate contact surface 63, and the tip 26 of the steel end plate 25 and the tip 26A of the steel end plate 25A overlap to form an end plate contact surface 64.

[0038] (2) The connecting plate 40 is partially annular and has a center line 44 (corresponding to the side plate contact surface 63) in the center in the vertical direction, with a first connecting protrusion 46 and bolt holes 55 formed on the lower end 43a side from the center line 44, and a first connecting protrusion 46 and bolt holes 55 formed on the upper end 43 side.

[0039] (3) When the connecting plates 40, 40 are stacked on the outer periphery of the overlapping lower pile 10 and upper pile 30, the center line connecting plate 44 is placed on the side plate contact surface 63, the first connecting projection 46 on the lower side of the connecting plate 40 is fitted into the first connecting recess 18 on the steel side plate 15 of the lower pile 10, and the first connecting projection 46 on the upper side of the connecting plate 40 is fitted into the first connecting recess 18A on the steel side plate 15A of the upper pile 30, and when tightened with bolts 55, 55, the connecting structure 73 is formed (Figure 7).

[0040] (4) This connecting structure 73 is applied to the foundation pile structure in the same way as the first connecting structure 70.

[0041] 3. Third connecting structure 75 (Figure 8)

[0042] (1) The third connecting structure 75 is the same as the second connecting structure 73 except that the structure of the end faces 17 and 17A of the steel side plates 15 and 15A is different.

[0043] (2) The lower pile 10, like the first connecting structure 70, is equipped with a steel end plate 25, which is formed by connecting a steel side plate 15 to the tip 12 of the concrete pile body 11. The upper pile 30 is equipped with a steel end plate 25A, which is formed by connecting a steel side plate 15A to the tip 12A of the concrete pile body 11A. When the lower pile 30 is placed on the upper end of the upper pile 10, the tip 17 of the steel side plate 15 and the tip 17A of the steel side plate 15A overlap to form a side plate contact surface 63, and the tip 26 of the steel end plate 25 and the tip 26A of the steel end plate 25A overlap to form an end plate contact surface 64. Here, the tip 26 of the steel end plate 25 forms a stepped structure with the outside lowered, and correspondingly the tip 26A of the steel end plate 25A forms a stepped structure with the outside lowered. Therefore, the side plate contact surface 63 consists of a side plate contact surface 63a and a side plate contact surface 63b, forming a hook shape, and constitutes a step 61 that functions similarly to the step 61 of the first and second connecting structures 73 and 75 (Figure 8).

[0044] (3) The connecting plate 40 is partially annular and has a center line 44 (corresponding to the side plate contact surface 63) in the center in the vertical direction, with a first connecting protrusion 46 and bolt holes 55 formed on the lower end 43a side from the center line 44, and a first connecting protrusion 46 and bolt holes 55 formed on the upper end 43 side.

[0045] (4) When the connecting plates 40, 40 are stacked on the outer circumference of the overlapping lower pile 10 and upper pile 30, the first connecting protrusion 46 on the lower side of the connecting plate 40 is fitted into the first connecting recess 18 of the steel side plate 15 of the lower pile 10, and the first connecting protrusion 46 on the upper side of the connecting plate 40 is fitted into the first connecting recess 18A of the steel side plate 15A of the upper pile 30, and when tightened with bolts 55, 55, the connecting structure 75 is formed (Figure 8).

[0046] (5) This connecting structure 73 is applied to the foundation pile structure in the same way as the first connecting structure 70. [Explanation of symbols]

[0047] 10 Lower stake 30 Upper stake 11, 11A Upper and lower pile body 11a, 11Aa Hollow section of the pile body 12, 12A The tip of the pile body (steel end plate side) 12a, 12Aa Base end of the pile body 15, 15A Steel side plates of upper and lower piles 16, 16A Outer surface of steel side plate 16a, 16Aa Inner surface of steel side plate 17, 17A Front surface of steel side plate 17a, 17Aa Base end faces of steel side plates 18, 18A First connecting groove of steel side plate 19, 19A Second connecting groove of the steel side plate 21, 21A Screw holes in steel side plates 25, 25A Steel end plates for upper and lower piles 26, 26A Tip of steel end plate 26a, 26Aa Base end of steel end plate 27, 27A Outer circumference of steel end plate 27a, 27Aa Inner circumference of steel end plate 33 PC steel rod (lower pile) 34. Reinforcement band (lower pile) 35 Coated steel pipe (upper pile) 40 Connecting Plates 41 Plate body 42. Inner surface of the plate body 42a Outer surface of the plate body 43 Upper edge of the plate body 43a Lower end of the plate body 44 Center line of the plate body 46 First connecting protrusion 47 The tip surface of the first connecting protrusion 48 One side edge of the first connecting ridge (on the center line side) 48a Other side edge of the first connecting protrusion 51 Second connecting protrusion 52 The tip surface of the second connecting protrusion 53. One side edge of the second connecting ridge (on the center line side) 53a Other side edge of the second connecting protrusion 55 Bolt holes (bolt through holes) 56 One side edge of the bolt hole (center line side) 56a Other side edge of the bolt hole 61. Difference in height between upper and lower piles 63, 63a, 63b Side plate contact surfaces (of upper and lower piles) 64 (End plate contact surface of upper and lower piles) 70, 73, 75 connection structure 71 volts

Claims

[Claim 1] A connecting structure for an upper and lower pile, characterized in that a donut-shaped steel end plate is provided on the longitudinal end face of a concrete pile body, and a short cylindrical steel side plate covering the outer wall of the pile body is connected to the steel end plate to form an upper and lower pile, the upper and lower piles are connected by joining the steel end plates, and the inner surface of a partially annular connecting plate is tightly fastened to the outer surface of the steel side plate, as described below. (1) The steel end plates of the upper pile and the lower pile are brought into contact with each other at the end plate contact surfaces, and the steel side plates of the upper pile and the lower pile are brought into contact with each other at the side plate contact surfaces. (2) A step is formed between the end plate contact surface and the side plate contact surface, which is approximately perpendicular to the horizontal plane. (3) The connecting plate is connected to the steel side plate by bolts that pass through bolt holes in the connecting plate. (4) The thickness of the connecting plate near the bolt through-hole is T, and on the inner surface of the plate body, which is made by bending a flat plate of thickness T into an arc shape in plan view, a first connecting protrusion of height t1 and a second connecting protrusion of height t2 are provided in series from the side closest to the side plate contact surface on the upper pile side and the lower pile side, respectively, and the heights t1 and t2 are the heights from the inner surface of the plate body. (5) On the lower pile side, the distance from the side plate contact surface to the upper edge of the first connecting ridge is defined as h01, and the distance from the lower edge of the first connecting ridge to the upper edge of the second connecting ridge is defined as h12. On the upper pile side, the distance from the side plate contact surface to one lower side edge of the first connecting ridge is defined as h01, and the distance from the other upper side edge of the first connecting ridge to one lower side edge of the second connecting ridge is defined as h2. h01=h1, h12=h2 It was formed by [this method]. (6) The outer surface of the steel end plate of the upper pile and the outer surface of the steel side plate of the lower pile are formed with a first connecting recess and a second connecting recess, respectively, into which the first connecting protrusion and the second connecting protrusion can be fitted. (7) The horizontal edges of the first connecting protrusion and the horizontal edges of the second connecting protrusion are formed perpendicular to the inner surface of the connecting plate. (8) The thickness T of the connecting plate body is A≦T≦(h1+h2)÷(√3) and B≦T≦(t1+t2) That's what I decided. A and B are the minimum thickness of the connecting plate that can withstand the shear force generated by the tensile force acting on the bolt.

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