How to install a reverse-cast support

Abstract

To provide a reversely driven column erection method capable of accurately erecting a reversely driven column in a concrete pile, and a reversely driven column.SOLUTION: Provided is the reversely driven column erection method for erecting a reversely driven column 1 in a pile hole 31 provided in a foundation 30 comprises the steps of: fixing an accuracy holding steel material 20 extending downward to a lower end of an embedment 3 of the reversely driven column 1; inserting the reversely driven column 1 to which the accuracy holding steel material 20 is fixed into the pile hole 31; and fixing the accuracy holding steel material 20 and the embedment 3 to a concrete pile. Also provided is the reversely driven column 1 used for the method.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention is a method for erecting inverted supports. By law Regarding. [Background technology]

[0002] The inverted construction method is known as a construction method for constructing a building having an aboveground portion and an underground portion. In the inverted construction method, before excavating the ground to construct the underground frame, inverted support columns for supporting the aboveground portion of the building are erected in pile holes provided in the ground, so that the aboveground portion can be constructed on the inverted support columns while excavating the ground and constructing the underground frame. This makes it possible to shorten the construction period of the building compared to a construction method in which the construction of the aboveground portion is carried out after the construction of the underground portion is completed.

[0003] In such inverted construction methods, when the inverted pillar has a certain length, a first-in-first-out construction method is generally adopted. In the first-in-first-out construction method, the inverted pillar is inserted into the pile hole before concrete is poured into the pile hole, and then the concrete is poured into the pile hole, so that the pillar is fixed to the cast-in-place concrete pile at the root portion (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-54164 A Summary of the Invention [Problem to be solved by the invention]

[0005] If an inverted support pillar is fixed to a concrete pile at an angle to the vertical, it will have a significant impact on its fit with the beam and construction of the above-ground portion, so it is necessary to support the inverted support pillar in a precisely vertical position until the concrete pile hardens.

[0006] However, when concrete is poured into a pile hole with the inverted support inserted, there is a problem in that the concrete may flow due to height imbalances, and this flow may apply lateral pressure to the embedded portion, reducing the verticality of the inverted support.

[0007] The present invention has been made in consideration of the above problems, and its object is to provide a method for erecting an inverted support pillar that can be accurately erected into a concrete pile. Law The purpose is to provide. [Means for solving the problem]

[0008] The method for erecting an inverted support of the present invention is a method for erecting an inverted support in a pile hole provided in the ground, A step of erecting a reinforcing bar at a predetermined position on the bottom side of the pile hole; A step of fixing a steel material for maintaining accuracy extending downward to a lower end of the root portion of the inverted support; and a step of inserting the inverted support to which the steel material for maintaining accuracy is fixed into the pile hole. After the inverted support pillar to which the precision-retaining steel material is fixed is inserted into the pile hole, concrete is poured into the pile hole. The precision-maintaining steel material and the insertion portion Place-hitting and a step of fixing the concrete pile.

[0009] In the method for erecting a reverse-driven support of the present invention having the above-mentioned configuration, it is preferable that the precision-maintaining steel material has at least one through hole. Effect of the Invention

[0011] According to the present invention, a method for erecting a cast-in-place support pillar capable of erecting a cast-in-place support pillar into a concrete pile with high accuracy is provided. Law can be provided. [Brief description of the drawings]

[0012] [Figure 1] This is a front view of an inverted support used in a method for installing an inverted support in one embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Diagram 3] FIG. 2 is an enlarged front view of the precision-maintaining steel material shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line BB in FIG. [Diagram 5] FIG. 1A is a diagram showing a pile hole drilled in the ground, and FIG. 1B is a diagram showing the state in which a reinforcing bar has been placed in the pile hole shown in FIG. [Figure 6] FIG. 1(a) is a diagram showing the state in which an inverted support pillar with precision-maintaining steel material fixed thereto is inserted into a pile hole, and FIG. 1(b) is a diagram showing the state in which the precision-maintaining steel material is buried in concrete poured into the pile hole. [Figure 7] FIG. 1(a) is a diagram showing the state in which the precision-maintaining steel material and part of the embedded portion are buried in the concrete poured into the pile hole, and FIG. 1(b) is a diagram showing the state in which the concrete pile has been formed by the concrete poured into the pile hole. [Figure 8] This figure shows the state in which the above-ground part is being constructed while the underground part is being constructed after the inverted support pillars are fixed to the concrete piles. [Figure 9] FIG. 13 is an enlarged front view of a precision-maintaining steel material according to a modified example. [Figure 10] 10 is a cross-sectional view taken along line CC in FIG. [Figure 11] 4 is a diagram showing a part of a modified inverted support pillar to which the precision-maintaining steel material shown in FIG. 3 is fixed. FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along the line DD in FIG. [Figure 13] 9 is a diagram showing a part of a modified inverted support pillar to which the precision-maintaining steel material shown in FIG. 8 is fixed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a method for installing an inverted support and an inverted support according to one embodiment of the present invention will be described in detail with reference to the drawings.

[0014] The inverted-cast support pillar 1 shown in FIG. 1 is to be erected in a pile hole provided in the ground by a method for erecting an inverted-cast support pillar according to one embodiment of the present invention.

[0015] The inverted support 1 is formed in a straight columnar shape of a predetermined length. In this embodiment, as shown in FIG. 2, the inverted support 1 is a box-shaped structure formed of a steel pipe with a rectangular cross section, and the inside is hollow. On the outer peripheral surface of the lower part of the inverted support 1, a plurality of studs 2 for engaging the inverted support 1 with the mat slab constituting the underground frame are arranged vertically and horizontally at a predetermined interval from each other and fixed. In FIG. 1, for convenience, only one stud 2 is given a reference number. The part of the inverted support 1 below the part where the plurality of studs 2 are fixed is the embedded part 3. The embedded part 3 is a part of the inverted support 1 that is inserted into the concrete poured in the pile hole and fixed to the concrete pile when the concrete hardens. The lower end of the inverted support 1 is closed by a lower end closing wall 4.

[0016] The inverted support 1 may have a configuration in which a pliers (temporary stake) 10 is attached to the upper end. The pliers 10 may be, for example, a straight, hollow pillar of a given length made of a steel pipe with a rectangular cross section of the same dimensions as the inverted support 1, with a pair of hanging hooks 11 at the upper end and multiple wing-shaped stoppers 12 fixed to the side to prevent it from falling.

[0017] A precision-maintaining steel material 20 is fixed to the lower end of the embedded portion 3 of the inverted-cast support 1. The precision-maintaining steel material 20 extends downward from the lower end of the embedded portion 3 of the inverted-cast support 1.

[0018] As shown in Figures 3 and 4, in this embodiment, the precision-maintaining steel material 20 is formed of an H-shaped steel. Specifically, the precision-maintaining steel material 20 includes a web 21 formed of a thick plate in an elongated rectangular shape, and a pair of flanges 22 each formed of a thick plate in an elongated rectangular shape and connected to both sides of the web 21, and the cross-sectional shape perpendicular to the up-down direction is a uniform H-shape from the upper end to the lower end. The precision-maintaining steel material 20 is fixed at its upper end to the lower surface of the lower end closing wall 4 of the inverted support pillar 1 by, for example, welding, in an orientation coaxial with the inverted support pillar 1.

[0019] The width dimension (horizontal width dimension of the flanges 22) and depth dimension (dimension between the outer surfaces of the pair of flanges 22) of the precision-maintaining steel material 20 are smaller than the horizontal width dimension and depth dimension of the embedded portion 3 of the inverted support 1. In other words, the precision-maintaining steel material 20 is narrower than the embedded portion 3 of the inverted support 1.

[0020] The precision-maintaining steel material 20 is preferably configured to have at least one through hole 23. In this embodiment, the precision-maintaining steel material 20 is configured to have five circular through holes 23 that penetrate the web 21 horizontally and are arranged at equal intervals in the vertical direction at the center position in the width direction of the web 21, and five circular through holes 23 that penetrate the flange 22 horizontally and are arranged at equal intervals in the vertical direction at both sides of the web 21 of each flange 22. The number, arrangement, and shape of the through holes 23 provided in the precision-maintaining steel material 20 can be changed in various ways. The through holes 23 are made to have a size that allows the concrete before hardening to pass through.

[0021] Next, we will explain the procedure for erecting an inverted support pillar 1 into a pile hole drilled in the ground using the inverted support pillar erection method of this embodiment when constructing a building having above-ground and underground portions using the inverted construction method.

[0022] First, as shown in Fig. 5(a), a pile hole 31 of a predetermined depth is excavated using a drill or other excavation device at a planned position for erecting a pile support 1 in the ground 30 of a construction site where a building is to be constructed by the inverted driving method. In the illustrated example, the shape of the pile hole is cylindrical with the diameter expanding only at the bottom, but the shape can be changed as appropriate. Next, as shown in Fig. 5(b), a reinforcing bar 32 is erected at a predetermined position on the bottom side of the pile hole 31.

[0023] 1, a precision-maintaining steel material 20 extending downward is fixed to the lower end of the embedded portion 3 of the inverted support 1. The precision-maintaining steel material 20 may be fixed to a member constituting the embedded portion 3 of the inverted support 1 in advance at a factory, or may be fixed to the lower end of the embedded portion 3 of the inverted support 1 at the construction site.

[0024] In addition, pliers 10 are attached to the upper end of the reverse driving support 1.

[0025] Next, as shown in Fig. 6(a), the inverted driving support 1 with the precision-maintaining steel material 20 fixed to its lower end is hung by a crane (not shown) using a wire 33 connected to the hanging hook 11 of the pliers 10, and inserted from the lower end into the pile hole 31. At this time, a stand 34 is installed above the opening of the pile hole 31, and the inverted driving support 1 and the pliers 10 are guided by guide rollers 35 provided on the stand 34 while being inserted into the pile hole 31 in a vertical position. In addition, multiple pantograph-type jacks 36 are attached to the outer circumferential surface of the inverted driving support 1 at positions facing each other across the axis of the inverted driving support 1.

[0026] When the reverse driving support 1 is inserted to a position where its lower end reaches a predetermined depth in the pile hole 31, the stopper 12 is supported by the stand 34, and the reverse driving support 1 is held at that position. The vertical position of the reverse driving support 1 is adjusted by the journal jack 37 provided on the stand 34. Next, multiple pantograph-type jacks 36 are opened and the jacks 36 are abutted against the wall of the pile hole 31. When the reverse driving support 1 is inserted to a predetermined depth in the pile hole 31, the pliers 10 are supported by the guide rollers 35, so that the reverse driving support 1 is supported in a vertical position by the jacks 36 and the guide rollers 35 that are separated vertically. By adjusting the degree of opening of the left and right pantograph-type jacks 36 and the position of the guide rollers 35, the verticality of the reverse driving support 1 is appropriately adjusted so as to be within a predetermined range. The verticality of the inverted support pole 1 can be measured using an inclinometer (not shown) attached to the outer circumferential surface of the inverted support pole 1.

[0027] Next, a tremie pipe 38 is erected in the pile hole 31, and concrete 39 is poured into the inside of the pile hole 31 through the tremie pipe 38 to fix the precision-maintaining steel material 20 and the embedded portion 3 to the hardened concrete 39, i.e., the cast-in-place concrete pile in which the reinforcing bar 32 is buried.

[0028] Here, the concrete 39 is gradually poured into the pile hole 31 at a predetermined pouring speed, so that, as shown in Fig. 6(b), before the height of the concrete 39 poured into the pile hole 31 from the bottom of the pile hole 31 reaches the root portion 3 of the inverted-casting support 1, the precision-retaining steel material 20 is embedded in the unhardened concrete 39 and fixed to the hardening concrete 39 from below. As a result, the inverted-casting support 1 is supported in the pile hole 31 via the hardened concrete 39 in the precision-retaining steel material 29 fixed to the lower end of the root portion 3 before the concrete 39 has reached the root portion 3.

[0029] From this state, when the concrete 39 is gradually poured into the pile hole 31 at a predetermined pouring speed, the concrete 39 reaches the embedded portion 3 as shown in Fig. 7(a). At this time, the inverted driving support 1 is supported in the pile hole 31 via the hardened concrete 39 at the precision-maintaining steel material 29 fixed to the lower end of the embedded portion 3. Therefore, even if the unhardened concrete 39 flows due to height deviation and the flow applies lateral pressure to the embedded portion 3, the inverted driving support 1 is accurately maintained in a vertical position without being displaced by the lateral pressure.

[0030] Then, concrete 39 is gradually poured into the pile hole 31 at a predetermined pouring speed until the concrete 39 reaches the height of the upper end of the embedded portion 3, as shown in FIG. 7(b). At this time, the inverted support 1 is fixed to the precision-maintaining steel material 29 and the hardened concrete 39 in the embedded portion 3, i.e., the cast-in-place concrete pile in which the reinforcing bars 32 are embedded.

[0031] In this way, according to the method of installing an inverted support of this embodiment, the precision-maintaining steel material 20 extending downward is fixed to the lower end of the root portion 3 of the inverted support 1, and the inverted support 1 with the precision-maintaining steel material 20 fixed thereto is inserted into the pile hole 31. After that, concrete 39 is poured into the pile hole 31 to fix the precision-maintaining steel material 20 and the root portion 3 to the concrete pile. This prevents the inverted support 1 from shifting out of position due to the flow of the concrete 39 before hardening, and allows the inverted support 1 to be installed accurately into the concrete pile.

[0032] Since the precision-maintaining steel material 20 is thinner than the root portion 3 of the inverted-cast support 1, when the precision-maintaining steel material 20 is embedded in unhardened concrete 39, even if the concrete 39 flows, the lateral pressure that the precision-maintaining steel material 20 receives from the concrete 39 is smaller than the lateral pressure that the root portion 3 receives, thereby reducing the risk of the inverted-cast support 1 becoming misaligned.

[0033] In particular, in the method for erecting a reverse-cast support of this embodiment, when the precision-maintaining steel material 20 is configured to have at least one through hole 23, even if the concrete 39 flows when the precision-maintaining steel material 20 is embedded in unhardened concrete 39, the concrete 39 flows through the through hole 23, thereby further reducing the lateral pressure that the precision-maintaining steel material 20 receives from the concrete 39. This prevents the precision-maintaining steel material 20 from shifting out of position when embedded in unhardened concrete 39, and allows the precision-maintaining steel material 20 to be erected more accurately into the concrete pile.

[0034] Using the same procedure as above, a predetermined number of inverted support columns 1 required for the building are fixed to the respective concrete piles in a predetermined number of pile holes 31 provided in the ground 30. When all of the inverted support columns 1 are fixed to the hardened concrete piles in the corresponding pile holes 31, the pile holes 31 are backfilled, and then, as shown in Fig. 8, the aboveground portion 40 of the building is constructed by supporting the inverted support columns 1. At the same time, the ground 30 is excavated to a predetermined depth, and concrete is poured into the bottom of the excavated ground from a tremie pipe 38 to form a pressure-resistant plate for the underground structure of the building, and other work is carried out to construct the underground portion 41.

[0035] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit and scope of the present invention.

[0036] In the above embodiment, a precision-maintaining steel material 20 made of H-shaped steel is fixed to the lower end of the root portion 3 of the box-shaped inverted support 1, but the shape or form of the inverted support 1 and the precision-maintaining steel material 20 can be modified in various ways.

[0037] For example, as shown in Figs. 9 and 10, the precision-maintaining steel material 20 made of cross H-shaped steel may be fixed to the lower end of the root portion 3 of the box-shaped inverted support 1. Specifically, the precision-maintaining steel material 20 may have a pair of webs 21 each formed of a thick plate in an elongated rectangular shape and perpendicular to each other at the center position in the width direction, and four flanges 22 each formed of a thick plate in an elongated rectangular shape and connected to both sides of each web 21, so that the cross-sectional shape perpendicular to the vertical direction is a uniform cross H shape from the upper end to the lower end. Even in this case, the precision-maintaining steel material 20 is preferably configured to have at least one through hole 23, for example, a configuration in which each of the pair of webs 21 has five circular through holes 23 that penetrate the web 21 horizontally and are arranged at equal intervals in the vertical direction. By configuring the precision-maintaining steel material 20 as a cross H-shaped steel, the precision-maintaining steel material 20 can be made symmetrical in all directions, making it difficult for it to move inside the concrete 39. In addition, a plurality of studs 24 for integrating the precision-maintaining steel material 20 with the concrete 39 may be attached to the outward facing surfaces of the pair of left and right flanges 22 .

[0038] In addition, in this embodiment, the inverted support 1 is box-shaped, but the inverted support 1 may be configured to be formed of cross H-shaped steel. Specifically, as shown in Fig. 11 and Fig. 12, the inverted support 1 may be configured to have a pair of webs 1a each formed of a thick plate in an elongated rectangular shape and perpendicular to each other at the center position in the width direction, and four flanges 1b each formed of a thick plate in an elongated rectangular shape and connected to both sides of each web 1a, so that the cross section perpendicular to the up-down direction is a uniform cross H shape from the upper end to the lower end.

[0039] Furthermore, when the inverted support pillar 1 is configured to be formed of cross H-shaped steel, the precision-maintaining steel material 20 may be formed of H-shaped steel as shown in Fig. 11, or may be formed of cross H-shaped steel as shown in Fig. 13. In either case, it is preferable that the precision-maintaining steel material 20 is formed thinner than the inverted support pillar 1. [Explanation of symbols]

[0040] 1. Reverse-strike support 1a Web 1b Flange 2 Studs 3. Root 4 Lower end closing wall 10 Yattoko 11 Hanging hook 12 Stopper 20 Precision maintenance steel material 21 Web 22 Flange 23 Through hole 24 Stud 30 Ground 31 Pilehole 32 Reinforcement 33 Wire 34 Mounting 35 Guide roller 36 Jack 37 Journal Jack 38 Ptolemy Tube 39 Concrete 40 Above ground part 41 Underground part

Claims

1. A method for erecting a reverse-cast support pillar in a pile hole provided in the ground, comprising: A step of erecting a reinforcing bar at a predetermined position on the bottom side of the pile hole; A step of fixing a precision-maintaining steel material extending downward to a lower end of the root portion of the inverted support; A step of inserting the reverse-cast support to which the precision-maintaining steel material is fixed into the pile hole; A method for erecting an inverted support, comprising the steps of: inserting the inverted support to which the precision-maintaining steel material is fixed into the pile hole; and then pouring concrete into the pile hole to fix the precision-maintaining steel material and the embedded portion to a cast-in-place concrete pile.

2. The method for installing a reverse-driven support pillar according to claim 1 , wherein the precision-maintaining steel material has at least one through hole.

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