Suspended formwork for filling concrete and filling method for hollow piles

Abstract

To provide a suspended form for infilled concrete in which a filling range (depth) can be adjusted in response to changes in a pile head level due to construction errors.SOLUTION: A male threaded portion 26 is provided at a lower end of a suspension reinforcing bar 24 for arranging a receiving bottom 21 on which concrete is placed in a hollow space 11 of a hollow pile 10 at a predetermined height, and a pair of nuts 27a, 27b screwed onto the male threaded portion 26 are provided. In a state where through-holes 22 are provided in a peripheral edge of the receiving bottom 21, and the male threaded portion 26 of the suspension reinforcing bar 24 is inserted into each of the through-holes 22, the pair of nuts 27a, 27b screwed onto the male threaded portion 26 hold peripheral edges of the through holes 22 of the receiving bottom 21 from above and below to connect the receiving bottom 21 to the lower ends of the suspension reinforcing bars 24. As a result, by moving threaded positions of the nuts 27a, 27b in a longitudinal direction of the male threaded portion 26, the receiving bottom 21 can be moved in a longitudinal direction of the suspension reinforcing bars 24 in response to construction errors of a pile head level.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a hanging formwork used to hold concrete poured into a hollow space within a specified depth range from the head of a hollow pile when filling the head of the hollow pile, and a method of filling a hollow pile using the hanging formwork. [Background technology]

[0002] In foundation construction methods for houses, apartment buildings, and other structures, the pile foundation method, in which hollow piles are installed to reach the supporting layer, etc., and a footing is formed on the head of these hollow piles, is widely used when constructing structures on soft ground, liquefiable ground, etc.

[0003] When hollow piles are used in this type of pile foundation construction method, the head of the hollow pile is reinforced by pouring concrete of the same strength as the concrete used for the footing within a specified depth of the head of the pile. In particular, for steel pipe piles, it is recommended that concrete be filled from the head of the pile to a depth of at least the pile diameter as a buckling prevention measure.

[0004] When filling the pile head of such a hollow pile, a suspended formwork 120 as shown in FIG. 4 is generally used (see Patent Document 1

[0037] , [FIG. 10]).

[0005] This suspended formwork 120 is equipped with a receiving base 121 on which poured concrete is placed to prevent it from falling downward, and a hanging reinforcing bar 124 which suspends this receiving base 121 at a predetermined depth position from the pile head.

[0006] As an example, the suspended formwork 120 described in Patent Document 1 cited above has a receiving bottom 121 formed of synthetic resin in a dish shape with a raised edge, and the lower end of a hanging reinforcing bar 124 having an engaging portion 125 formed at its upper end by bending it into a U-shape is fixed to the raised portion provided on the edge of the receiving bottom 121 by a method such as welding or adhesive.

[0007] When the suspended formwork 120 constructed in this manner is inserted into the hollow space 111 from the head of the hollow pile 110 with the receiving bottom 121 facing downward, as shown in Figures 5(A) and (B), the engaging portion 125 provided at the upper end of the hanging bar 124 engages with the upper end opening edge of the hollow pile 110, thereby holding the receiving bottom 121 at a predetermined depth from the upper end of the hollow space 111 of the hollow pile 110.

[0008] As a result, when concrete for filling is poured into the hollow space 111 from the head of the hollow pile 110 with the aforementioned suspended formwork 120 attached, the poured concrete is supported on the receiving base 121 and cannot fall downward beyond the receiving base 121, and concrete can only be filled into the head portion above the receiving base 121. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2001-182078 A Summary of the Invention [Problem to be solved by the invention]

[0010] In the above-mentioned pile foundation, the head of the installed hollow pile 110 is integrated with the footing 130 by attaching a beveled bar (not shown) or the like to the head of the hollow pile 110 and then embedding the head of the pile into the footing 130 a predetermined length.

[0011] In order to enable such embedding, the pile head level of the hollow pile 110 is designed to be higher than the underside 131 of the footing 130. For example, the pile head level LV is designed so that the head of the hollow pile 110 can be embedded in the footing 130, with a length that is the minimum embedding length required to obtain the above-mentioned integration plus a certain margin that takes into account construction errors, etc. D is set.

[0012] Here, in the suspended formwork 120 described in Patent Document 1, the receiving bottom 121 can be accurately positioned at a predetermined position determined by the length of the suspended reinforcing bar 124 from the pile head, and therefore filling can be accurately performed from the pile head to a predetermined depth.

[0013] However, in the construction of the hollow pile 110, the actual pile head level LV of the constructed hollow pile 110 may vary due to construction error ±ε. R However, the design pile head level LV D However, it may be lower or higher by the aforementioned construction error ±ε.

[0014] Thus, the design pile head level LV D On the other hand, the actual pile head level LV R Even if a construction error ±ε occurs in the foundation, so long as such error ±ε is within the range of the preset allowable error, the foundation can be constructed without correcting the head of the hollow pile 110 by extending or cutting it, or without revising the design of the footing 130 to be constructed thereafter.

[0015] As a result, the actual pile head level LV R However, the design pile head level LV D When an error -ε occurs that is lower than the above (see Figure 5(A)), the pile head covering length (buried depth) L C is shortened by this error -ε.

[0016] Also, the actual pile head level LV R is the designed pile head level LV D When an error +ε occurs that is higher than the above (see Figure 5(B)), the pile head covering length (buried depth) L C becomes longer by this error + ε.

[0017] In contrast, in the conventional hanging formwork 120 described with reference to FIG. 4, the distance from the engaging portion 125 to the top surface of the receiving bottom 121 is constant and cannot be changed, so the position of the top surface of the receiving bottom 121 is the actual pile head level LV R Therefore, the depth is always constant.

[0018] Therefore, the actual pile head level LV R is the designed pile head level LV D When the error -ε is smaller than the actual distance W2 from the bottom surface 131 of the footing 130 to the top surface of the receiving bottom 121 (see Figure 5(A)), R is the design distance W2 D The actual pile head level LV is longer than the above error -ε. R is the designed pile head level LV D When the error + ε is higher than the actual distance W2 from the bottom surface 131 of the footing 130 to the top surface of the receiving bottom 121 (see Figure 5(B)), R is the design distance W2 D It is shorter by the aforementioned error + ε.

[0019] Here, the upper end portion of the hollow pile 110 is buried in the footing 130 (cover length L C As mentioned above, the part (the part 110) is integrated with the footing 130 and becomes part of the footing 130, so the reinforcement range of the head of the hollow pile 110 by filling is the actual pile head level LV R What is important is not to what extent the foundation is reinforced from the underside 131 of the footing 130, but to what depth the foundation is reinforced.

[0020] Therefore, the design pile head level LV D On the other hand, the actual pile head level LV of the installed hollow pile 110 R When construction error ±ε occurs, especially in the actual pile head level LV R is the designed pile head level LV D Even if the height is higher than the design depth, it is desirable to be able to pour the filling concrete from the underside 131 of the footing 130 to at least the design depth.

[0021] In addition, in the conventional hanging formwork 120, the lower end of the hanging reinforcing bar 124 was connected to the receiving bottom 121 by welding or adhesive as described above, which resulted in low strength of the connecting parts. The weight of the poured concrete filling could cause the connecting parts to come loose, causing the receiving bottom 121 to tilt or fall, making it impossible to support the concrete filling on the pile head. This would require replacing the hanging formwork 120 and re-pouring the concrete filling, which would require extra labor and also lead to the consumption of extra materials.

[0022] Therefore, there is a demand for a highly reliable suspended formwork 120 that is relatively simple in structure, low in cost, and strong enough not to be damaged by the weight of the filled concrete, etc.

[0023] The present invention has been made to eliminate the drawbacks of the above-mentioned conventional technology, and its first objective is to provide a suspended formwork for filled concrete that allows the depth of filling from the pile head to be varied when a construction error occurs in the actual pile head level of a constructed hollow pile compared to the designed pile head level, thereby making it possible to fill the concrete to at least the designed depth from the underside of the footing, for example.

[0024] A second object of the present invention is to provide a hanging formwork for filling concrete, which has a relatively simple structure yet is highly strong and will not be damaged by the weight of the poured concrete, thereby preventing the need for additional labor and materials required for redoing the filling work, and a method of filling hollow piles using said hanging formwork. [Means for solving the problem]

[0025] The means for solving the problems are described below together with the reference numerals used in the description of the embodiment of the invention. The reference numerals are used to clarify the correspondence between the description of the claims and the description of the embodiment of the invention, and needless to say, are not used to restrict the interpretation of the technical scope of the present invention.

[0026] In order to achieve the above object, the hanging formwork 20 for filling concrete of the present invention is as follows: A suspended formwork 20 for filling concrete comprises a receiving base 21 on which poured filling concrete is placed, and a plurality of hanging reinforcing bars 24 for positioning the receiving base 21 at a predetermined height position within the hollow space 11 of the hollow pile 10, the hanging reinforcing bars 24 having upper ends each equipped with a locking portion 25 that is locked to the upper end opening edge of the hollow pile 10, and a lower end connected to the peripheral portion of the receiving base 21, The hanging reinforcing bars 24 are inserted into the through holes 22 that penetrate the receiving bottom 21, and the lower ends of the hanging reinforcing bars 24 and the receiving bottom 21 are fixed at any position in the longitudinal direction of the hanging reinforcing bars 24. freely year ,Design pile head level LV D The allowable error is set, and the placement height of the receiving bottom 21 in the hollow pile 10 is set to the designed pile head level LV D The above allowable error range is allowed for the This is characterized by the above (Claim 1).

[0027] In an embodiment, A suspended formwork 20 for filling concrete comprises a receiving base 21 on which poured filling concrete is placed, and a plurality of hanging reinforcing bars 24 for positioning the receiving base 21 at a predetermined height position within the hollow space 11 of the hollow pile 10, the hanging reinforcing bars 24 having upper ends each equipped with a locking portion 25 that is locked to the upper end opening edge of the hollow pile 10, and a lower end connected to the peripheral portion of the receiving base 21, Each of the hanging reinforcing bars 24 is provided with a male threaded portion 26 having a male thread formed within a range of a predetermined length from the lower end of the hanging reinforcing bar 24, and a pair of fixing members 27a, 27b screwed into the male threaded portion 26, At the connection positions of the receiving bottom 21 and the lower ends of the hanging reinforcing bars 24, through holes 22 are provided through the receiving bottom 21, With the male screw portion 26 of each of the hanging reinforcing bars 24 inserted into each of the through holes 22, the pair of fixing members 27a, 27b screwed into the male screw portion 26 clamps the peripheral portion of the through hole 22 of the receiving bottom 21 from above and below, thereby connecting the lower end of each of the hanging reinforcing bars 24 to the receiving bottom 21, This is characterized in that the receiving bottom 21 can be moved in the longitudinal direction of the hanging bar 24 by moving the screwing position of the fixing members 27a, 27b in the longitudinal direction of the male threaded portion 26 (Claim 2).

[0028] The aforementioned receiving bottom 21 can be formed from a disk-shaped steel plate (Claim 3).

[0029] Moreover, it is preferable to sandwich a washer 28 having a larger diameter than the lower fixing member 27b between the bottom surface of the receiving bottom 21 and the lower fixing member 27b (claim 4).

[0030] The male screw portion 26 may be provided by threading a predetermined area of ​​the lower end of the hanging reinforcing bar 24, and the fixing members 27a, 27b may be formed by nuts (claim 5).

[0031] In addition, the method for filling a hollow pile of the present invention is a method for filling a hollow pile 10 using any of the above-mentioned hanging formwork 20 for filling concrete. , Execution Actual pile head level LV of the constructed hollow pile 10 R However, the design pile head level LV D When an error +ε occurs that is higher than the above allowable error range (see Figure 3(B)), the actual pile head level LV R to the actual upper surface of the receiving bottom 21 W1 R However, the pile head level LV in the design D from the designed distance W1 to the upper surface of the receiving bottom 21 D The fixed position of the receiving bottom 21 relative to the lower end of the hanging reinforcing bar 24 is adjusted so that the distance is longer by the error + ε. The method is characterized in that filling concrete is poured into the hollow space 11 of the hollow pile 10 to which the adjusted hanging formwork 20 is attached from the pile head (claim 6).

[0032] In the filling method of the hollow pile having the above configuration, Actual pile head level LV of the installed hollow pile RHowever, the design pile head level LV D When an error -ε occurs that is lower than the allowable error range (see Figure 3(A)), the actual pile head level LV R to the actual upper surface of the receiving bottom 21 W1 R However, the pile head level LV in the design D from the designed distance W1 to the upper surface of the receiving bottom 21 D The fixed position of the receiving bottom 21 relative to the lower end of the hanging reinforcing bar 24 is adjusted so that the distance is shorter by the error -ε. After the adjustment, filling concrete may be poured into the hollow space 11 of the hollow pile 10 to which the suspended formwork 20 is attached from the head of the pile (claim 7). Effect of the Invention

[0033] With the configuration of the present invention described above, the following remarkable effects can be obtained by filling the hollow pile 10 using the suspended formwork 20 for filling concrete of the present invention.

[0034] A male threaded portion 26 is provided within a predetermined range from the lower end of each hanging reinforcing bar 24, and a pair of fixing members 27a, 27b are respectively screwed into the male threaded portion 26. The male threaded portion 26 is inserted into the through hole 22 provided in the receiving bottom 21, and the pair of fixing members 27a, 27b clamps the peripheral portion of the through hole 22 of the receiving bottom 21 from above and below, thereby connecting the receiving bottom 21 to the lower end of the hanging reinforcing bar 24. By moving the screwing position of the fixing members 27a, 27b in the longitudinal direction of the male threaded portion 26, the receiving bottom 21 can be fixed to any position in the longitudinal direction of the hanging reinforcing bar 24.

[0035] In this way, the receiving base 21 can be fixed at any position in the longitudinal direction of the hanging reinforcing bar 24, so that the designed pile head level LV D The actual pile head level LV of the installed hollow pile 10 R In the case where a construction error of ±ε occurs in the receiving base 21, the position of the receiving base 21 in the height direction can be changed according to the construction error of ±ε.

[0036] As a result, the actual pile head level LV of the installed hollow pile 10 R However, the design pile head level LV D When an error +ε occurs that is higher than the allowable error range (see Figure 3(B)), the actual pile head level LV R Distance W1 from the actual top surface of the receiving bottom 21 R The design pile head level LV D Distance W1 from the designed top surface of the receiving bottom 21 D By increasing the error + ε, the actual distance W2 from the bottom surface 31 of the footing 30 to the top surface of the receiving bottom 21 is R The design value W2 D This enabled the pile head reinforcement effect to be achieved as designed.

[0037] In addition, the actual pile head level LV of the installed hollow pile 10 R However, the design pile head level LV D If an error -ε occurs that is lower than the above allowable error range, the actual pile head level LV R Distance W1 from the actual top surface of the receiving bottom 21 R The design pile head level LV D Distance W1 from the designed top surface of the receiving bottom 21 D Even if the actual distance W2 from the bottom surface 31 of the footing 30 to the top surface of the receiving bottom 21 is the same as the actual distance W2 R is the design value W2 D Therefore, the reinforcing effect of the pile head due to the filling will not decrease compared to the design value.

[0038] However, even in this case, the actual pile head level LV R Distance W1 from the actual top surface of the receiving bottom 21 R The design pile head level LV D Distance W1 from the designed top surface of the receiving bottom 21 D By moving the receiving bottom 21 so that the distance is reduced by the error -ε, the actual distance W2 from the lower surface 31 of the footing 30 to the upper surface of the receiving bottom 21 is R The design distance W2 D[See Figure 3(A)], which enabled the reinforcement effect of the pile head by the filling to be achieved as designed.

[0039] Furthermore, as mentioned above, the connection between the receiving bottom 21 and the lower end of the hanging bar 24 is configured to be fixed by clamping it between fixing members 27a, 27b such as nuts screwed onto the male threaded portion 26.This allows the receiving bottom 21 to move up and down, while providing a stronger connection between the receiving bottom 21 and the lower end of the hanging bar 24 than when fixed by methods such as welding or adhesive.

[0040] As a result, with the conventional suspended formwork 120, it was possible to prevent the labor burden and consumption of additional materials that would be required to redo installation work or redo pouring of the filling concrete due to damage to the suspended formwork 120, which would occur when the connection between the receiving bottom 121 and the lower end of the suspended rebar 124 was released (due to welding or peeling off of the adhesive).

[0041] In the configuration in which the aforementioned support bottom 21 is formed from a disk-shaped steel plate, a suspended formwork 20 with greater strength can be provided compared to the suspended formwork of Reference 1 (Patent Document 1

[0037] ), which used a synthetic resin support bottom 121. Meanwhile, the disk-shaped support bottom 21 has a simpler structure than a dish-shaped support bottom, making it possible to improve the strength of the suspended formwork 20 while suppressing increases in manufacturing costs.

[0042] In a configuration in which a washer 28 having a larger diameter than the lower fixing member 27b is sandwiched between the bottom surface of the receiving bottom 21 and the lower fixing member 27b, a relatively wide area around the periphery of the through hole 22 of the receiving bottom 21 can be supported from the bottom side by the washer 28, and the strength of the suspended formwork 20 can be further improved by adding a relatively inexpensive part.

[0043] Although not shown in the figure, a configuration for providing the male threaded portion 26 on the hanging reinforcing bar 24 may be such that the hanging reinforcing bar 24 itself is formed from a threaded reinforcing bar, and the male threaded portion 26 is formed over the entire length of the hanging reinforcing bar 24. In this case, nuts for threaded reinforcing bars may be used as the aforementioned fixing members 27a, 27b.

[0044] However, in this configuration, the threaded reinforcing bars used are more expensive than ordinary deformed reinforcing bars, and the aforementioned nuts used as fixing members 27a, 27b are also expensive, making the entire suspended formwork 20 expensive and reducing its price competitiveness in the market.

[0045] In contrast, in a configuration in which a male thread portion 26 is provided by threading a specified area of ​​the lower end of the hanging reinforcing bar 24, as shown in an enlarged view in Figure 1, it is possible to use ordinary deformed bars, which are cheaper than threaded reinforcing bars, as the hanging reinforcing bar 24, and it is possible to use general-purpose nuts, which are cheaper than nuts for threaded reinforcing bars, as the fixing members 27a, 27b, making it possible to provide the hanging formwork 20 of the present invention at a lower cost. [Brief description of the drawings]

[0046] [Figure 1] FIG. 2 is a schematic front view of the suspended formwork of the present invention attached to the head of a hollow pile (steel pipe pile). [Diagram 2] An explanatory plan view of the receiving base when fitted into a hollow pile (steel pipe pile). [Diagram 3] This is an explanatory diagram of how to adjust the height position of the receiving base when a construction error of ±ε occurs in the actual pile head level LVR compared to the design pile head level LVD. (A) is the case when an error of -ε occurs such that the actual pile head level LVR is lower than the design pile head level LVD, and (B) is the case when an error of +ε occurs such that the actual pile head level LVR is higher than the design pile head level LVD. [Figure 4] FIG. 1 is a perspective view of a conventional suspended formwork (corresponding to FIG. 10 of Patent Document 1). [Diagram 5] The diagrams show the state when a conventional suspended formwork is attached to the head of a hollow pile (steel pipe pile). (A) shows the case where an error -ε occurs such that the actual pile head level LVR of the constructed hollow pile is lower than the design pile head level LVD, and (B) shows the case where an error +ε occurs such that the actual pile head level LVR is higher than the design pile head level LVD. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] Next, an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0048] In addition, the attached drawings show the hanging formwork 20 of the present invention attached to a steel pipe pile 10 as an example, however, the hanging formwork 20 of the present invention is not limited to steel pipe piles and can be widely applied to various types of hollow piles, such as concrete piles and steel pipe wrapped concrete piles, as long as they are hollow piles.

[0049] The symbol 10 in Figures 1 to 3 is a hollow pile (steel pipe pile), and the hanging formwork 20 of the present invention is attached within the hollow space 11 in the head of such a hollow pile 10 and is used when filling the head of the hollow pile 10 with concrete, similar to the conventional hanging formwork 120 described with reference to Figures 4 and 5.

[0050] This hollow pile 10 has a predetermined covering length L above the underside 31 of the footing 30 to be constructed on top of it. c The hollow pile 10 is constructed so as to protrude upward by a distance of L c The above range is configured so that it can be embedded within the footing 30 and integrated with the footing 30.

[0051] The pile head level of this hollow pile 10 is determined at the time of design, but the design pile head level LV D For this, a tolerance is set within the range that does not cause any structural problems, and the design pile head level LV D The actual pile head level LV of the installed hollow pile 10 R Installation error ±ε(LV R -LV D ) is within this allowable error range, the footing 30 is constructed on top of it as is without making any height adjustments such as extending or cutting the hollow pile 10, and without making any design changes to the footing 30 (for example, moving the position of the underside 31 of the footing 30).

[0052] Therefore, the covering length (buried length) L of the hollow pile 10 to the footing 30 c may vary within the tolerance range mentioned above.

[0053] Thus, the design pile head level LV D and actual pile head level LV R Even if a construction error ±ε occurs between the bottom surface 31 of the footing 30 and the top surface of the receiving bottom 21 of the suspended formwork 20, the actual distance W2 R The design distance W2 D In order to match the amount of fill concrete filled in this portion with the design value, the suspended formwork 20 of the present invention allows the receiving bottom 21 to be raised and lowered.

[0054] An example of the configuration of the suspended formwork 20 of the present invention in which the receiving bottom 21 can be moved up and down in this manner is shown in Figs.

[0055] This suspended formwork 20, like the conventional suspended formwork 120 described with reference to Figure 4, is composed of a plurality of suspended reinforcing bars 24 and a support base 21 connected to the lower ends of the suspended reinforcing bars 24, and in this embodiment, the lower ends of the six suspended reinforcing bars 24 are configured to be connected to the peripheral portion of the support base 21 at equal intervals of 60° in the circumferential direction.

[0056] This hanging bar 24 is formed from reinforcing bars such as deformed bars, and has an engaging portion 25 at its upper end which is formed by bending outward at a predetermined length. When the hanging formwork 20 is inserted into the hollow space 11 from the upper end side of the hollow pile 10 with the receiving bottom 21 facing downward, this engaging portion 25 engages with the upper opening edge of the hollow pile 10, and the hanging formwork 20 can be attached in a hanging state at a predetermined position at the upper end side of the hollow space 11 of the hollow pile 10.

[0057] In the embodiment shown, the upper end of the hanging bar 24 is bent outwardly into a semicircular arc at a predetermined length to form the aforementioned engaging portion 25, but the configuration of this engaging portion 25 may be, for example, formed by bending a predetermined range of the upper end of the hanging bar 24 linearly in the outer circumferential direction into an inverted L-shape, or it may be formed by bending it into a U-shape similar to the conventional hanging formwork 120 described with reference to Figure 4.The shape of the engaging portion 25 is not limited to that shown in the figure, so long as it is capable of engaging with the upper opening edge of the hollow pile 10 when the hanging formwork 20 is inserted into the hollow space 11 of the hollow pile 10.

[0058] However, a configuration in which the upper end side of the hanging bar 24 is curved into a semicircular arc to form an engaging portion 25 as shown in Figure 1 is preferable in that the hanging formwork 20 can be positioned in the center of the hollow space 11 simply by inserting it into the hollow space 11 of the hollow pile 10.

[0059] A receiving bottom 21 is connected to the lower end of this hanging bar 24 so as to enable movement of the hanging bar 24 in the longitudinal direction.

[0060] In order to enable such movement of the receiving bottom 21, a male threaded portion 26 is formed within a predetermined range from the lower end of the hanging bar 24, as shown in an enlarged view in FIG.

[0061] In the illustrated embodiment, this male thread portion 26 is formed by cutting a male thread within a predetermined range from the lower end of the hanging bar 24 formed from deformed reinforcing bars, but instead of this configuration, although not shown in the illustration, the entire hanging bar 24 may be formed from threaded reinforcing bars such as "Tough Neji Bar" (Kyoei Steel Works, Ltd.), thereby forming the male thread portion 26 over the entire length of the hanging bar 24.

[0062] A pair of fixing members 27a, 27b, or in the illustrated embodiment, a pair of nuts are screwed onto the male threaded portion 26 of the hanging reinforcing bar 24 formed in this manner, and with the upper nut 27a screwed onto the male threaded portion 26, the receiving bottom 21 is inserted into the through hole 22 provided in the hanging reinforcing bar 24. The lower nut 27b is screwed onto the male threaded portion 26 from the lower end of the hanging reinforcing bar 24, and the upper nut 27a and the lower nut 27b clamp the peripheral portion of the through hole 22 provided in the receiving bottom 21, thereby connecting the hanging reinforcing bar 24 to the lower end thereof.

[0063] With this configuration, by moving the screwing position of nuts 27a, 27b relative to the longitudinal direction of male threaded portion 26, the receiving bottom 21 can be raised and lowered in the longitudinal direction of the hanging bar 24, and therefore in the vertical direction.

[0064] Furthermore, when the hanging reinforcing bar 24 is formed from threaded reinforcing bar as described above, a nut for threaded reinforcing bar (for example, a lock nut used to fix a coupler for threaded reinforcing bar) can be used as the fixing member 27 described above.

[0065] However, since threaded reinforcing bars and nuts for threaded reinforcing bars are relatively expensive, the configuration shown in the figure, in which a male thread is cut into the lower end of the deformed reinforcing bar to form a male thread portion 26 and general-purpose nuts 27a, 27b are used as fixing members, is more advantageous in terms of cost.

[0066] It is desirable to sandwich a washer 28 having a larger diameter than the lower nut 27b between the bottom surface of the receiving bottom 21 and the lower nut 27b. By attaching such a washer 28, when filling concrete is poured onto the receiving bottom 21, the area supporting the bottom surface of the receiving bottom 21 is increased compared to when the bottom surface of the receiving bottom 21 is directly supported by the lower nut 27b, thereby further improving the strength of the suspended formwork 20.

[0067] The aforementioned receiving bottom 21 is formed in a circular shape that is slightly smaller in plan view than the inner diameter of the hollow pile 10 to be filled, as shown in Figure 2, and a gap δ is formed between the inner wall of the hollow pile 10 and the outer periphery of the receiving bottom 21, which can prevent the poured filling concrete from passing through but allows the receiving bottom 21 to be smoothly inserted into the hollow space 11.

[0068] This receiving bottom 21 may be formed from synthetic resin or the like, similar to the conventional suspended formwork 120 described with reference to Figure 4, and may also be formed in a dish shape with a raised edge, but in this embodiment, the receiving bottom 21 has a simple structure formed from a disk-shaped steel plate, thereby increasing the strength of the receiving bottom 21 while reducing manufacturing costs.

[0069] Through holes 22 are formed at a predetermined interval in the circumferential direction on the peripheral portion of the receiving bottom 21, and the male threaded portion 26 provided at the lower end of the aforementioned hanging bar 24 can be inserted into these through holes 22.

[0070] In the configuration of the suspended formwork 20 of this embodiment, in which the receiving bottom 21 is suspended by six hanging bars 24, six through holes 22 are provided at equal intervals of 60° around the circumference of the receiving bottom 21, but the number of hanging bars 24 may be less than six or more than six as long as the receiving bottom 21 can be suspended stably, and the number of through holes 22 provided in the receiving bottom 21 can be changed depending on the number of hanging bars 24 used.

[0071] In addition, the symbol 12 in Figure 2 is a so-called "piece" that is attached to transmit rotational force to the steel pipe pile 10 when the steel pipe pile 10 is driven into place by rotary pressing, and the embodiment shown in the figure shows an example in which this piece 12 is attached to the inner wall of the steel pipe pile 10, a so-called "inner piece."

[0072] The receiving bottom 21 of the hanging formwork 20 attached to the steel pipe pile 10 using this type of "inner frame" has a notch 23 formed in it corresponding to the formation position of the frame 12, so that the receiving bottom 21 does not interfere with the frame 12 when it is inserted into the hollow space 11 of the steel pipe pile 10.

[0073] Although not shown in the figure, in the case of a steel pipe pile 10 that employs a so-called "external link" in which the aforementioned link 12 is attached to the outer wall side of the steel pipe pile 10, there is no need to provide the aforementioned notch 23 in the receiving bottom 21.

[0074] However, even if a hanging formwork 20 with a notch 23 in the receiving base 21 is used for a steel pipe pile 10 that employs an "external frame," the fill concrete poured after the hanging formwork 20 is installed will hardly fall downward through this notch 23, or even if it does fall, the amount will be small, so the hanging formwork 20 with a notch 23 in the receiving base 21 may be used as a common hanging formwork 20 for steel pipe piles 10 with either an internal frame or external frame configuration.

[0075] Filling of the hollow pile 10 using the hanging formwork 20 constructed as described above can be carried out as follows.

[0076] Due to construction errors, the actual pile head level LV of the constructed hollow pile 10 R However, the design pile head level LV D If an error +ε occurs that is higher than the actual pile head level LV (see Figure 3(B)), the actual pile head level LV can be adjusted by adjusting the screw-in position of the nuts 27a and 27b relative to the male threaded portion 26. R Distance W1 from the actual top surface of the receiving bottom 21 R The design pile head level LV D Distance W1 from the designed top surface of the receiving bottom 21 D The time is adjusted so that it is longer by the aforementioned error + ε.

[0077] After the suspended formwork 20 with the position of the receiving bottom 21 adjusted in this manner is attached to the head of the hollow pile 10, filling concrete is poured into the hollow space 11.

[0078] This allows the actual pile head level LV R Distance W1 from the top surface of the receiving bottom 21 R is the design pile head level LV D Distance W1 from the top surface of the receiving bottom 21 D As a result, the amount of concrete poured into the hollow space 11 of the hollow pile 10 increases compared to the design value.

[0079] However, by making such an adjustment, when the underside 31 of the footing 30 to be constructed later is used as the reference, the actual distance W2 from the underside 31 of the footing 30 to the upper surface of the receiving base 21 is R The design distance W2 D can be matched with

[0080] As a result, the portion of the pile head of the hollow pile 10 that is not buried in the footing 30 and is below the underside 31 of the footing 30, i.e., the portion that requires reinforcement by filling, can be reinforced within the designed range, preventing the strength of the actually constructed pile head from decreasing compared to the designed strength of the hollow pile 10 head.

[0081] On the other hand, the actual pile head level LV of the hollow pile 10 (110) installed R However, the design pile head level LV D If an error -ε occurs that is lower than the actual pile head level LV R Distance W1 from the actual top surface of the receiving bottom 21 (121) R The design pile head level LV D Distance W1 from the designed top surface of the receiving bottom 21 (121) D If the actual distance W2 from the bottom surface 31 (131) of the footing 30 (130) to the top surface of the receiving bottom 21 (121) is R is the design distance W2 D (See Figure 5(A)).

[0082] In this case, the reinforced range of the hollow pile 10 (110) located below the underside 31 (131) of the footing 30 (130) is greater than the designed reinforced range, so that the strength of the head of the hollow pile 10 (110) may increase relative to the design value but will not decrease.

[0083] Therefore, the actual pile head level LV of the installed hollow pile 10 R Distance W1 from the top surface of the receiving bottom 21 R However, the design pile head level LV D Distance W1 from the top surface of the receiving bottom 21 D The fixing position of the receiving bottom 21 may be adjusted so as to coincide with the above.

[0084] However, even in this case, the actual pile head level LV, as shown in Figure 3(A), R Distance W1 from the actual top surface of the receiving bottom 21 R The design pile head level LV D It is also possible to adjust the distance from the upper surface of the receiving bottom 21 to be shorter by the error -ε compared to the designed distance.

[0085] By configuring in this way, the actual distance W2 from the lower surface 31 of the footing 30 to the upper surface of the receiving bottom 21 is R The design distance W2 D By matching this with the above, the reinforcement range of the pile head below the underside 31 of the footing 30 can be ensured as designed.

[0086] Although not shown in the figure, the design pile head level LV D and the actual pile head level LV of the installed steel pipe pile R If the levels match (if there is no error ±ε), adjust the screwing position of the nuts 27a and 27b relative to the male thread 26 to obtain the actual pile head level LV R Distance W1 from the top surface of the receiving bottom 21 R The design pile head level LV D Distance W1 from the top surface of the receiving bottom 21 D Match with.

[0087] By configuring in this way, the actual distance W2 from the lower surface 31 of the footing 30 to the upper surface of the receiving bottom 21 is R Regarding the design distance W2 D can be matched with [Explanation of symbols]

[0088] 10 Hollow pile (steel pipe pile) 11 Hollow space 12 frames 20 Suspended formwork 21 Receiver 22 Through hole 23 Cutout 24 Suspension steel bar 25 Locking part 26 Male thread 27a Upper fixing member (upper nut) 27b Lower fixing member (lower nut) 28 Washer 30 Footing 31 Underside (of footing) 110 Hollow pile 111 Hollow space 120 Suspended formwork 121 Bottom 124 Suspension Steel Bar 125 Locking part 130 Footing 131 Underside of footing L.V. D Design pile head level L.V. R Actual pile head level L C Cover length W1 D Design pile head level LV D Distance from the top surface of the designed receiving base W1 R Actual pile head level LV R Distance from the actual top surface of the receiving base W2 D Design distance from bottom of footing to top of receiving base W2 RActual distance from the bottom of the footing to the top of the support δ Gap between the inner diameter of the hollow pile and the outer diameter of the receiving base ±ε Construction error

Claims

1. A suspended formwork for filled concrete, comprising a receiving base on which poured concrete is placed, and a plurality of suspension bars for positioning the receiving base at a predetermined height within the hollow space of a hollow pile, the suspension bars having upper ends each equipped with a locking portion that is locked to the upper end opening edge of the hollow pile, and a lower end connected to the peripheral portion of the receiving base, A suspended formwork for filled concrete, characterized in that the hanging bars are each inserted into a through hole that passes through the receiving bottom, the lower ends of each hanging bar and the receiving bottom can be freely fixed at any position in the longitudinal direction of the hanging bars, a tolerance is set for the design pile head level, and the positioning height of the receiving bottom within the hollow pile can be moved within the range of the tolerance for the design pile head level.

2. Each of the hanging reinforcing bars is provided with a male threaded portion having a male thread formed within a predetermined length from the lower end of the hanging reinforcing bar, and a pair of fixing members each screwed into the male threaded portion, The suspended formwork for filled concrete as described in claim 1, characterized in that the receiving bottom can be fixed at any position in the longitudinal direction of the hanging bars by inserting the male threaded portions of each of the hanging bars into each through hole of the receiving bottom and clamping the peripheral portions of the through holes of the receiving bottom from above and below with a pair of fixing members screwed into the male threaded portions.

3. 3. The suspended formwork for filling concrete according to claim 2, wherein the receiving bottom is formed of a disk-shaped steel plate.

4. 4. The suspended formwork for filling concrete according to claim 2 or 3, characterized in that a washer having a larger diameter than the lower fixing member is sandwiched between the bottom surface of the receiving bottom and the lower fixing member.

5. A suspended formwork for filling concrete as claimed in any one of claims 2 to 4, characterized in that the male threaded portion is threaded within a predetermined range of the lower end of the suspension bar, and the fixing member is formed by a nut.

6. A method for filling a hollow pile using a hanging form for filling concrete according to any one of claims 1 to 5, When an error occurs in which the actual pile head level of the constructed hollow pile is higher than the design pile head level within the range of the allowable error, the fixed position of the receiving bottom relative to the lower end of the hanging reinforcing bar is adjusted so that the distance from the actual pile head level to the actual upper surface of the receiving bottom is longer than the distance from the design pile head level to the design upper surface of the receiving bottom by the amount of the error, A method for filling a hollow pile, characterized in that filling concrete is poured into the hollow space of the hollow pile to which the adjusted hanging formwork is attached, from the head of the pile.

7. When an error occurs in which the actual pile head level of the constructed hollow pile is lower than the design pile head level within the range of the allowable error, the fixed position of the receiving bottom relative to the lower end of the hanging reinforcing bar is adjusted so that the distance from the actual pile head level to the actual upper surface of the receiving bottom is shorter by the error than the distance from the design pile head level to the design upper surface of the receiving bottom; 7. The method for filling a hollow pile according to claim 6, further comprising pouring filling concrete into the hollow space of the hollow pile to which the adjusted hanging formwork is attached from the head of the pile.

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