JP5008532B2 - Pile head rebar fittings - Google Patents

Description

  The present invention relates to a pile head rebar connecting bracket for connecting a reinforcing bar to a pile head in a standing state when connecting a pile head of a foundation pile and a foundation of a structure via a reinforcing bar. .

In the construction of various civil engineering structures, regarding the installation of ready-made foundation piles (hereinafter referred to as “ready-made piles”), such as steel pipe piles and PC piles, reinforcing bars (hereinafter “ A method of connecting a ready-made pile and a structure by connecting a pile head rebar ”and a footing or the like on the structure side is widely performed. For example, as a method of connecting a pile head rebar to a pile head of a steel pipe pile, the lower end portion of the pile head rebar is directly welded to the outer peripheral surface of the pile head (Patent Document 1), or the outer periphery of the pile head There are known ones in which a threaded reinforcing bar or a deformed reinforcing bar having a threaded end is screwed through a coupler welded to a surface (Patent Document 2). However, when welding a pile head reinforcement or a coupler for standing it to the pile head of a steel pipe pile embedded in the ground, the work environment is not only restricted, Therefore, it is difficult to shorten the working time and is susceptible to the weather. On the other hand, when the welding work is performed in advance in a place other than the site such as a factory, when the steel pipe pile is driven, the pile head rebar or coupler welded to the end of the steel pipe pile interferes with the driving work. It is easy to lead to decline. In addition, when the steel pipe pile hits hard ground or rocks during driving and it becomes difficult to drive further (high stop), an extra part so that the protruding length from the ground surface will be the predetermined length After cutting out, there was a problem in that there was a case where a pile head rebar or coupler had to be re-welded to the pile head.
JP 2000-352062 A Japanese Patent Publication No. 3-54736

Therefore, a technique for avoiding direct welding between a steel pipe pile and a pile head reinforcing bar has been proposed. For example, steel bars are welded to the outer peripheral surface of a semi-circular steel band, a pair of them are arranged in a ring shape on the side of the pile head, and tightened with bolts and nuts (Patent Document 3), and further steel pipe piles After the outer periphery of a cylindrical steel ring having an inner diameter slightly larger than the outer diameter of the steel pipe is externally fitted to the pile head in a loosely fitted state, mortar or A material that is joined by filling and solidifying cement paste (Patent Document 4) is also known. By the way, the resistance with respect to the bending moment at the time of connecting a pile head reinforcement directly with respect to a steel pipe pile like patent document 1 is the distance in the radial direction from the center of a steel pipe pile to a pile head reinforcement, and a pile head. Since it becomes a product (moment) with the resistance of the reinforcing bar, it is advantageous in design to install the pile head reinforcing bar as far as possible from the outer peripheral surface of the steel pipe pile in the radially outward direction. Also in this tensile resistance force, the methods of Patent Documents 3 and 4 in which the pile head reinforcing bars are erected from the surface of the steel pipe pile at an interval are more advantageous than those of Patent Document 1. However, in the method of Patent Document 3, since the distance from the center of the steel pipe pile to the pile head reinforcement is determined by the plate thickness of the steel band, a thick material is used to increase the distance. In such a case, even if a pair of steel bands are tightened with bolts and nuts, the steel band is not easily deformed, and the pile itself has tolerances and is not necessarily a perfect circle. A close contact state cannot be obtained. For this reason, there is a problem that when a tensile force is applied to the pile head reinforcing bar, a slip is likely to occur between the steel band and the steel pipe pile, leading to a decrease in the tensile resistance. Furthermore, in the case of the method of Patent Document 4, the steel ring is not a structure for tightening the steel pipe pile, and the solidified material such as mortar in which the joining strength between the steel pipe pile and the steel ring is filled between the two is In order to secure sufficient joint strength, it is necessary to increase the length of the steel ring, and it is difficult to reduce the size of the pile head reinforcing bar connection bracket. There is room for further improvement.
Japanese Patent Publication No.1-40178 JP 2005-105812 A

  The present invention has been made in view of the state of the prior art as described above, and does not reduce the coupling force between a prefabricated pile such as a steel pipe pile and a structure, and the mounting work of the pile head reinforcement to the prefabricated pile is performed. An object of the present invention is to provide a pile head rebar connecting bracket that can be improved and can be applied to a pile head cut by a high stop and that can be easily downsized.

In order to solve the above-described problems of the prior art, in the pile head rebar connection fitting according to claim 1 of the present application, a plurality of rebar support members for supporting the pile head rebar embedded in the concrete foundation in an upright state are provided on the outer periphery. A cylindrical ring that is fixed on the surface at a predetermined interval and is externally fitted to the pile head of a pre-made pile, and the inner diameter of the cylindrical ring is reduced to the outer peripheral surface of the pile head. and a tightening member allowed to fixed pressed state, together with the cylindrical ring comprises a bulge portion of the at least one point on the circumference, employ a configuration wherein the clamping member is ing through a compression possible wedge to the bulging portion There is a feature in the point.

Furthermore, the pile head reinforcement fitting according to the claim 1, said cylindrical ring and a combination of a plurality of arc-shaped plate, its cylinder by these arc-shaped plate is pressed the wedge to the bulging portion An integrated configuration (claim 2) is also possible. Further, if the inner peripheral surface roughened by shot blasting or the like of the cylindrical ring, leading to the improvement of the tensile resistance than the frictional resistance increases (claim 3). Further, the use of couplers as said reinforcing bar supporting member, it is possible to omit the nut when mounting the pile head reinforcement (claim 4).

In the pile head reinforcing bar connecting bracket according to the present invention, the following effects can be obtained by adopting the above-described configuration.
(1) A welding on site when installing the pile head of the buried prefabricated piles unnecessary, it can be easily performed by using a clamping member comprising a click rust, the outer periphery of the pile head reinforcement fittings Since the pile head reinforcement can be simply attached using the reinforcing bar support member fixed to the surface, the workability related to the connection of the pile head reinforcement to the pile head is greatly improved.
(2) Since the pile head rebar fittings are fixed to the outer peripheral surface of the pile head by a tightening member in a pressure contact state, large static friction generated on the contact surface between the two against the tensile force applied to the pile head rebar Resisting by force, a firm connection with the ready-made pile is obtained. If the inner peripheral surface of the cylindrical ring is roughened in advance, the effect is further enhanced. For this reason, it is also possible to reduce the size of the pile head rebar connecting metal fitting by shortening the length of the cylindrical ring.
(3) Since the pile head rebar is installed in a standing state via a reinforcing bar support member fixed to the outside of the cylindrical ring and is located away from the outer peripheral surface of the ready-made pile, the eccentric moment according to the distance Works. This eccentric moment increases the compressive force generated between the cylindrical ring and the ready-made pile, so the tensile resistance force of the pile head reinforcement also increases, and it is possible to accurately secure the coupling force between the ready-made pile and the structure. it can.
(4) Since the pile head can be installed at a desired height position from the end face side or side face of the pile head after installation of the ready-made pile without any processing, the pile head is Even when the part is cut, it can be applied without hindrance, and does not get in the way when driven.
(5) When the cylindrical ring is divided into a plurality of arc-shaped plates, it is easier to manufacture than the integral type in which the cylindrical wall is continuous, and is not particularly bulky during storage and transportation. There is.
(6) When the cylindrical ring is an integrated type in which the cylindrical wall is continuous, the degree of freedom in selecting the fixing position of the reinforcing bar support member such as a coupler is higher than that of the split type.
(7) When a coupler is used as the reinforcing bar support member, the nut can be omitted when attaching the pile head reinforcing bar, leading to an improvement in the efficiency of the connection work.

As described above, the pile head reinforcing bar connecting metal fitting according to the present invention has a cylindrical ring reduced in diameter by a wedge fastening member and fixed to the outer peripheral surface of the pile head in a pressure contact state, and is fixed to the outside of the cylindrical ring. By adopting a configuration in which multiple pile head rebars are installed in a standing position at a position away from the outer peripheral surface of the prefabricated piles, the pile head rebar is streamlined on-site, and the pile head rebar is streamlined. The main feature is that a stable connection state is realized. That is, as shown in FIG. 1 (a), the cylindrical pile head reinforcing bar connecting fitting 2 according to the present invention is directed to the outer peripheral surface of the upper end of the ready-made pile 1, and the cylindrical ring 21 is fitted with an appropriate tightening member. Tighten in the direction to reduce the diameter. Thereby, the inner surface of the pile head reinforcing bar connecting fitting 2 is pressed against the ready-made pile 1, and a compressive force acts on the ready-made pile 1. And at the time of an earthquake, a bending moment and axial force act on the pile head of the ready-made pile 1 by the horizontal force. At this time, an eccentric moment proportional to the distance from the outer peripheral surface of the ready-made pile 1 acts on the pile head rebar 3 receiving the tensile force, as shown in FIG. Therefore, as schematically shown in FIG. 2, the compressive force N generated between the inner surface and the prefabricated pile 1 the outer surface of the cylindrical ring 21 by the eccentric moment, compression bending eccentric compression force N _a tension min min increase is the sum of the N _b, it lead to increase of the tensile resistance force F. Furthermore, if the inner peripheral surface of the cylindrical ring 21 is roughened by shot blasting or the like, the tensile resistance can be further improved by increasing the frictional resistance.

The pile head reinforcing bar connecting fitting 2 according to the present invention can be applied to various ready-made foundation piles. Specifically, a PHC pile, a PRC pile, a concrete pile with a shell steel pipe, a steel pipe pile, etc. are mentioned. That is, in this invention, it fits in the arbitrary height position of a pile head outer peripheral surface, it tightens from the outer side in the direction which diameter-reduces the cylindrical ring 21 with the fastening member which consists of a wedge , and is in a press-contact state with the ready-made pile 1 Since it is fixed, it does not require any processing on the pile head, and it can be easily and reliably mounted even by an unskilled person, greatly contributing to the rationalization of the connection work of the pile head rebar. In particular, in the installation work of the ready-made pile 1, there is a great feature in that the pile head rebar connecting fitting 2 can be applied as it is even when the pile head is cut by a high stop. Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is of course not limited to these embodiments, and within the technical idea of the present invention, such as changes in the material, shape, quantity, and position of each component. Of course, various modifications can be made.

3 to 7 show a reference example of a pile head reinforcing bar connecting metal fitting according to the present invention. 3 and 4 are a plan view and a front view, respectively, of the pile head rebar connecting bracket 2. In the illustrated pile head reinforcing bar connecting fitting 2, the cylindrical ring 21 is composed of a pair of semicircular arc-shaped plates 22. Each arc-shaped plate 22 is formed so that both end portions thereof are bent outward in the diameter direction and are formed into a substantially circular shape in a state where the bent portions 23 are overlapped with each other. Further, a coupler 24 as a reinforcing bar supporting member is fixed to the outer peripheral surface of each arc-shaped plate 22 by welding or the like so as to be parallel to the axial center of the cylindrical ring 21 with a predetermined interval therebetween. Further, two bolt insertion holes (not shown) are formed in the bent portions 23 on both ends of the arc-shaped plate 22, and two sets of bolts 41 and nuts 42 serving as fastening members 4 inserted therethrough are provided. The pair of arc-shaped plates 22 and 22 are integrated as a cylindrical ring 21 and can be tightened in the direction of diameter reduction.

  5 and 6 are a plan view and a front view, respectively, showing a state in which the pile head rebar connecting bracket 2 is attached to the upper end portion of the ready-made pile 1, and FIG. FIG. The pile head rebar fitting 2 includes a cylindrical ring 21 in which bolts 41 and nuts 42 are loosened, inserted from the upper end side of the ready-made pile 1, and two sets of upper and lower bolts 41 and nuts 42 at a predetermined height position of the upper end portion. The cylindrical ring 21 is reduced in diameter, and the inner peripheral surface of each arc-shaped plate 22 is pressed against the outer peripheral surface of the ready-made pile 1. Next, the pile head rebar 3 made of screw joints is attached by screwing to the coupler 24 of the pile head rebar connection fitting 2. In addition, when attaching the pile head reinforcement connecting metal fitting 2 to the ready-made pile 1, you may address from the side with respect to the ready-made pile 1 in the state which isolate | separated a pair of circular arc-shaped plate 22, and you may fasten with the bolt 41 and the nut 42.

FIGS. 8 to 14 show a first embodiment of a pile head reinforcing bar connecting fitting. FIGS. 8 and 9 are a plan view and a front view, respectively, of an arc-shaped plate used in this embodiment, and FIG. FIG. The arc-shaped plate 5 according to the present embodiment has a semicircular shape similar to that of the reference example, forms a pair of cylindrical rings, and is tightly integrated by a wedge which will be described later. At both end portions of each arc-shaped plate 5, wedge insertion portions 51 and 52 which are bulging portions are provided on the outer peripheral surface side. Each wedge insertion portion 51, 52 is half the length in the axial direction, and through holes 53, 54 having a substantially rectangular cross section are formed in parallel to the axis, and the wedge insertion portion 51 on one end side. Is closer to one peripheral side of the arc-shaped plate 5, and the wedge insertion portion 52 on the other end side is closer to the other peripheral side of the arc-shaped plate 5, and the positional relationship is shifted in the axial direction. Note that three couplers 55 are fixed to the outer peripheral surface of each arc-shaped plate 5 in the same manner as in the above embodiment.

  Next, a method for attaching the arcuate plate 5 according to the present embodiment will be described with reference to FIGS. First, as shown in FIGS. 11 and 12, a pair of arc-shaped plates 5 are addressed to the upper end portion of the ready-made pile 1 from the side surface at opposing positions, and the wedge insertion portions 51 and 52 on both ends are axially directed. To overlay. In this state, the positions of the through holes 53 and 54 are not completely coincident with each other, and are set so as to overlap only a part thereof. The wedges 6 and 6 are inclined with respect to the through holes 53 and 54 from the respective sides of the wedge insertion portions 51 and 52 in a state where the through holes 53 and 54 partially overlap in the axial direction. Are inserted so that they come into contact with each other, and further pressed from above and below. As a result of the pushing operation, the wedges 6 and 6 further enter, so that the wedge insertion portions 51 and 52 are attracted to each other by the action of the inclined surfaces of the wedges 6 and 6. Thereby, the inner peripheral surface of a pair of circular-arc-shaped plate 5 will be in a press-contact state with the outer peripheral surface of the ready-made pile 1, and the pile head reinforcement connecting bracket and the ready-made pile 1 will be couple | bonded firmly. Then attach the pile head rebar to the coupler. If the inner surface is tapered so that the through holes 53 and 54 of the wedge insertion portions 51 and 52 are completely overlapped, it is possible to tighten even one wedge.

By the way, although both the above-mentioned reference example and the example explained that arc-shaped plates 5 and 22 were divided into two in a semicircle shape, considering the pile diameter, workability, etc. of the ready-made pile to be applied, three or more divisions were made. Ru is possible der be in.

FIGS. 15 to 19 show a second embodiment of a pile head reinforcing bar connecting fitting, and FIGS. 15 and 16 are a plan view and a front view of a cylindrical ring used in this embodiment, respectively, and FIGS. c) is a plan view, a front view, and a side view, respectively, of the wedge used in this embodiment. The cylindrical ring 7 according to the present embodiment has a closed shape, and a part of the circumference is a bulging portion 71 that bulges outward in a U shape in plan view, and an inner portion thereof is a wedge insertion portion 72. . On the outer peripheral surface of the cylindrical ring 7, six couplers 73 as reinforcing bar support members are fixed at substantially equal intervals as in the above embodiment. The wedge 8 as a fastening member corresponding to the wedge insertion portion 72 has a shape in which a tapered portion 81 is formed on one surface of a rectangular parallelepiped.

  FIG. 18 is a plan view showing a mounting state of the above-mentioned pile head reinforcing bar connecting fitting, and FIG. 19 is a sectional view taken along line BB in FIG. At the time of attachment, the cylindrical ring 7 is inserted from the upper end portion of the ready-made pile 1, and the wedge 8 is pushed into the wedge insertion portion 72 from above at a predetermined height position. As the wedge 8 enters, the inner peripheral surface of the cylindrical ring 7 is drawn in the axial direction. As a result, the cylindrical ring 7 is in a pressure contact state with respect to the outer peripheral surface of the ready-made pile 1, and the pile head rebar connecting fitting and the ready-made pile 1 are firmly coupled. Then attach the pile head rebar to the coupler.

  In each of the above-described pile head reinforcing bar connecting brackets, the examples in which the coupler is used as the reinforcing bar support member have been described. However, a deformed reinforcing bar having a male threaded portion formed at the end using a simple pipe-shaped member. Can be fixed by a lock nut. Also, in order to further increase the distance between the reinforcing bar support member and the cylindrical ring, an appropriate spacing member such as a plate member is interposed between them, or the coupling between the reinforcing bar support member and the cylindrical ring is replaced by welding. Etc. may be performed.

It is explanatory drawing which shows a state when tensile force is loaded to the pile head reinforcement connected using the pile head reinforcement connecting bracket of this invention. It is explanatory drawing which shows the principal part of FIG. 1 typically. It is a top view of the pile head reinforcement connecting metal fitting which concerns on the reference example of this invention. It is a front view of the pile head rebar connecting metal fitting which concerns on the reference example of this invention. It is a top view which shows the attachment state of the pile head rebar connection metal fitting which concerns on the reference example of this invention. It is a front view which shows the attachment state of the pile head reinforcement connecting metal fitting which concerns on the reference example of this invention. It is a front view which shows the state which connected the pile head reinforcement to the pile head reinforcement connection metal fitting of FIG. It is a top view of the circular-arc-shaped plate which concerns on 1st Example of this invention. It is a front view of the circular arc plate concerning the 1st example of the present invention. It is the sectional view on the AA line of FIG. It is a top view which shows the state in the middle of attachment of the pile head reinforcement connecting metal fitting which concerns on 1st Example of this invention. It is a front view which shows the state in the middle of attachment of the pile head reinforcement connecting metal fitting which concerns on 1st Example of this invention. It is a top view which shows the state after attachment of the pile head reinforcement connecting metal fitting which concerns on 1st Example of this invention. It is a front view which shows the state after attachment of the pile head reinforcement connecting metal fitting which concerns on 1st Example of this invention. It is a top view of the cylindrical ring which concerns on 2nd Example of this invention. It is a front view of the cylindrical ring which concerns on 2nd Example of this invention. (A)-(c) is respectively a top view, a front view, and a side view of the wedge used in 2nd Example of this invention. It is a top view which shows the state after attachment of the pile head reinforcement connecting metal fitting which concerns on 2nd Example of this invention. It is the BB sectional view taken on the line of FIG.

  DESCRIPTION OF SYMBOLS 1 ... Ready-made pile, 2 ... Pile head reinforcement metal fitting, 3 ... Pile head reinforcement, 4 ... Fastening member, 5,22 ... Arc-shaped plate, 6 ... Wedge, 7, 21 ... Cylindrical ring, 8 ... Wedge, 23 ... Bending part, 24, 55, 73 ... Reinforcing bar support member, 51, 52 ... Wedge insertion part, 53, 54 ... Through hole, 71 ... Swelling part

Claims (4)

A cylinder in which a plurality of reinforcing bar support members that support pile head rebars embedded in a concrete foundation in an upright state are fixed to each other on the outer peripheral surface at predetermined intervals, and are externally fitted to the pile heads of ready-made piles And a tightening member for reducing the diameter of the cylindrical ring and fixing its inner peripheral surface to the outer peripheral surface of the pile head in a pressure-contact state, and the cylindrical ring has at least one swelling on the circumference. provided with a detection section, the clamping member is Rukuiatama reinforcement fitting such a press-fit can wedge in the bulged portion. It said cylindrical ring a plurality of arc-shaped plate or Rannahli, pile head according to claim 1 which they arcuate plates, characterized in that it is integrated into a cylindrical shape by press-fitting the wedge into the bulging portion Reinforcing bar connection bracket. 3. The pile head reinforcing bar connecting bracket according to claim 1, wherein an inner peripheral surface of the cylindrical ring is roughened. The pile head reinforcing bar connecting bracket according to any one of claims 1 to 3 , wherein the reinforcing bar supporting member is a coupler.

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