JP2006207124A - Steel-made pier structural body and its construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel-made pier structural body and its construction method capable of shortening a construction period of time and, at the same time, making a construction area smaller. <P>SOLUTION: The steel-made pier structural body is so constituted that a steel-made pier 1 supported by a footing pile 2 buried in the ground is erected, a reinforcing bar cage is positioned in an excavated pile shaft by excavating the ground, a cast-in-place pile formed by placing a concrete is used as the footing pile 2 and that the steel-made pier 1 is erected on the footing pile 2 by connecting a pier base section 27 to an anchor bolt 3 projected from the upper end thereof, and the steel-made pier structural body is so constituted that supporting members 23 and 24 supporting a perforated steel plate dowel 21 and the anchor bolt 3 in the concrete are arranged to a pile head section of the footing pile 2 in the circumferential direction together with vertical reinforcing bars 13 and 14 of the reinforcing bar cage and that the supporting members 23 and 24 and the perforated steel plate dowel 21 are interconnected so that force transmitted to the anchor bolt 3 from the steel-made pier 1 can be further transferred to the perforated steel plate dowel 21. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a steel pier structure in which a steel pipe column is erected on the ground based on a cast-in-place pile buried in the ground, and its construction method, and in particular, no footing interposed between the foundation pile and the steel pipe pier is required. The present invention relates to a steel pier structure and its construction method.

When standing steel piers, a steel pier structure is constructed by joining steel piers via footings to foundation piles buried in the ground. As one conventional example, one described in JP-A-8-269912 can be cited. FIG. 6 is a cross-sectional view showing a joint portion of a steel pier structure by footing described in the publication. In this conventional example, a plurality of studs 101 having a T-shaped cross section are attached to the inner surface of the lower end portion of the tubular steel pier 100, and a plurality of main bars 103 protrude upward from the footing 102. The lower part of the steel pier 100 is hardened by the concrete 104, so that the steel pier 100 and the footing 102 are combined, and this part has a steel plate concrete structure. The footing 102 is constructed on a group pile in which a plurality of foundation piles 105 having a relatively small diameter are embedded in the ground.
Japanese Patent Laid-Open No. 8-269912 (page 3, FIG. 1)

  By the way, in the conventional steel pier structure and its construction method, there existed a problem that the yard range which excavates the ground for construction will become large, and a construction period will take time. This is because in the steel pier structure of the conventional example, since the footing 102 is constructed on the group pile in which a large number of foundation piles 105 are embedded, the area is larger than that of the steel pipe pier 100. This is because the steel pier structure in which the foundation pile 105 is driven, the footing 102 on the foundation pile 105 is constructed, and the steel pipe pier 100 is erected on the footing 102 is increased in construction steps. In particular, the footing 102 requires a considerable amount of time, for example, the arrangement of the reinforcing bars for footing and the main reinforcing bars 103 and the placement of concrete. Therefore, when a steel pipe pier is erected on a median strip and an elevated road is constructed, lane control must be performed due to the large yard range, thereby causing traffic congestion. And the longer construction period will prolong such a situation and affect the deterioration of the surrounding environment and economic loss.

  Therefore, an object of the present invention is to provide a steel pier structure that shortens the construction period and reduces the construction area and a construction method thereof in order to solve the above-described problems.

  The steel pier structure according to the present invention is a steel pier supported by a foundation pile buried in the ground, and a steel pier is placed in a pile hole dug into the ground. A cast-in-place pile formed by erection and concrete is used as the foundation pile, and the steel pier is erected on the foundation pile by connecting the pier base to the anchor bolt protruding from the upper end of the foundation pile. In the pile head of the foundation pile, a plurality of support members supporting the perforated steel plate gibel and the anchor bolt in the concrete are arranged in the circumferential direction together with the longitudinal bars of the reinforcing steel cage, and the steel pier The support member and the perforated steel plate dowel are connected so that the force transmitted from the to the anchor bolt is further transmitted to the perforated steel plate dowel.

Further, in the steel pier structure according to the present invention, the foundation pile is covered with an outer peripheral steel pipe on the head of the pile, and the perforated steel plate gibel and the support member are fixed to the outer peripheral steel pipe. It is preferable that
In the steel pier structure according to the present invention, the support member is a support tube in which the anchor bolt is inserted and fixed, and the support tube projects in a radial direction and is integrally formed. It is preferable to be fixed to the inner peripheral surface of the outer peripheral steel pipe.
In the steel pier structure according to the present invention, the support plate of the support member projects further from the support pipe in the direction of the center axis of the foundation pile, and a plurality of holes are formed in the projecting portion to form a diver. It is preferable that
In the steel pier structure according to the present invention, an annular positioning plate is fixed to the inner peripheral surface of the outer peripheral steel pipe, and the support pipe is fixed integrally to the positioning plate in advance. It is preferable that the support pipe is positioned by fixing to the steel pipe.

  On the other hand, the construction method of the steel pier structure according to the present invention is a method for constructing a steel pier structure formed by joining a steel pier to a foundation pile buried in the ground, and a tubing device. Rotating and press-fitting the casing into the ground, excavating the soil in the casing, building a rebar cage in the pile hole dug into the casing, and the pile head of the foundation pile In the upper part of the pile hole, the perforated steel plate dowel and the support member are integrally formed so that a plurality of perforated steel plate dowels and support members for supporting the anchor bolts are arranged in the circumferential direction together with the vertical bars of the reinforcing bar cage. Connecting the pier base to the anchor bolt projecting from the pile head of the foundation pile and the process of placing the fixed outer steel pipe, the process of building the foundation pile by cast-in-place piles that can be poured concrete into the pile hole Let Steel piers and having a step of standing on the foundation pile.

  Therefore, according to the steel pier structure and its construction method according to the present invention, the cast-in-place pile is used as the foundation pile, and the steel pier is directly connected to the foundation pile, so that a plurality of foundation piles are driven. In contrast to the conventional structure in which the steel pier is erected on the top via the footing, the construction period can be shortened in that a plurality of foundation piles are not driven and a footing is not formed. Therefore, deterioration of the surrounding environment and economic loss due to traffic congestion can be suppressed. Furthermore, since no footing is required, the range for traffic regulation can be narrowed by narrowing the construction area.

  In addition, according to the steel pier structure according to the present invention, a plurality of support members supporting the perforated steel plate gibel and the anchor bolt in the concrete of the foundation pile are arranged in the circumferential direction together with the longitudinal bars of the reinforcing steel cage, The supporting member and the perforated steel plate gibel were integrated with the outer peripheral steel pipe so that the force transmitted from the steel bridge pier to the anchor bolt was further transmitted to the perforated steel plate gibel. For this reason, simply embedding anchor bolts in the pile heads of the foundation piles cannot secure the area of resistance against pull-out shear of the concrete, but because the force is transmitted through the perforated steel plate gibel, However, it is no longer necessary to secure a resistance area against the pulling shear of concrete. Furthermore, by surrounding the concrete forming the foundation pile with the outer peripheral steel pipe, the strength of the concrete can be improved, the shear strength of the perforated steel plate gibber can be increased, and the band reinforcement can be omitted.

  Next, an embodiment of a steel pier structure and a construction method thereof according to the present invention will be described below with reference to the drawings. The steel pier of this embodiment is constructed in order to pass an elevated road on a general road, for example. For this purpose, as shown in FIG. 1, a two-lane road 200 passes on both sides of the median strip, and an elevated road 300 is constructed so as to pass in parallel. In this elevated road 300, steel piers 1 are erected at a predetermined interval in a central separation zone, and a viaduct 301 is connected so as to be bridged over the steel piers. The viaduct 301 is a steel floor board box girder ramen bridge, and is spanned between steel piers 1 arranged at intervals of 40 m.

  In the present embodiment, a steel pier structure and its construction method in such an elevated road construction will be described. Here, the steel pier structure means a configuration including a foundation pile 2 portion buried in the ground and a steel pier 1 portion erected with respect to the foundation pile 2. The steel pier 1 is connected to a foundation pile 2 which is constructed by building a reinforcing bar into a pile hole excavated from the ground and pouring concrete there.

  Therefore, first, the excavation of the pile hole for constructing the foundation pile 2 is performed at the position where the steel pier 1 is erected. FIG. 2 is a diagram showing an outline of the construction process of the foundation pile 2. For the construction of the foundation pile 2, an all-round rotating tubing device 60 is used. As shown in FIG. 2 (a), the tubing device 60 grips and rotates the casing 70, thereby rotating and press-fitting the casing 70 into the ground while excavating the ground with the excavation bit at the tip. That is, the tubing device 60 grips the casing tube 70 with the chuck member, the rotation of the drive motor is applied to the rotating body integrally provided with the chuck member, and the rotating body is further lowered by the lifting cylinder. As a result, the casing tube 70 descends while rotating and is press-fitted into the ground.

  In the casing tube 70 that is rotationally press-fitted into the ground by the driving of the tubing device 60, for example, a hammaglab 80 is dropped, and the earth and sand inside is scraped to form a pile hole. The pile hole is dug until it reaches the support layer of the hard ground beyond the soft ground, and the foundation pile 2 is placed so as to be supported by the support layer. That is, in the dug hole, as shown in Fig. 2 (b), a rebar cage in which several vertical bars are connected by a plurality of upper and lower circular bars is built, and then inserted into the pile hole. The concrete is poured by the treme tube 90 made.

  At that time, as shown in FIG. 2C, the casing tube 70 is pulled out of the pile hole by pulling up the tubing device 60. Such pulling out of the casing tube 70 must be done with attention to the co-up of the reinforcing bars, and is performed in parallel with the placing of concrete.

  Next, the steel pier 1 is erected on the foundation pile 2 as shown in FIG. Therefore, the anchor bolt 3 is projected from the upper end of the foundation pile 2 formed as described above, and the pier base is fastened and fixed to the anchor bolt 3 by a nut. The joint structure with the steel pipe pier 1 formed on the foundation pile 2 has a structure which will be described later including the anchor bolt 3, and if the roll caused by an earthquake occurs on the steel pier 1 supporting the elevated road 300, the roll The force generated by is effectively transmitted to the foundation pile 2.

FIG. 3 is a perspective view showing a joint portion between the steel pier 1 and the foundation pile 2 of the steel pier structure. 4 and 5 are cross-sectional views showing the joint portion between the steel pier 1 and the foundation pile 2 in particular. FIG. 4 shows a cross section taken along the line AA in FIG. 5, and FIG. 4 shows a BB cross section.
As shown in FIG. 4, the foundation pile 2 includes an RC pile portion 2 a in which a plurality of vertical bars 11 and 12 are arranged on the circumference in double with an inner periphery and an outer periphery, and concrete is cast thereon, and a little above the RC pile portion 2 a. Concrete is cast with a reduced diameter, and a pile head 2b is formed around which an outer peripheral steel pipe 20 is covered. Longitudinal bars 13 and 14 having different lengths are connected to the pile head 2b by a coupler 15 in accordance with the joint structure with the steel pipe pier.

  On the inner peripheral surface of the outer peripheral steel pipe 20 constituting the pile head 2b of the foundation pile 2, a perforated steel plate dowel 21 is welded and fixed along the central axis so as to project radially inward. The perforated steel plate gibel 21 is formed by penetrating a long strip-shaped steel plate in two rows which are the radial direction of the foundation pile 2 and a large number of holes 21a which are longitudinal in the axial direction. When the concrete constituting the foundation pile is placed, the hole 21a is filled with concrete so that the steel and the concrete are integrated. A plurality of the perforated steel plate gibels 21 are arranged at equal intervals on the inner peripheral surface of the outer peripheral steel pipe 20, and the vertical bars 13 and 14 are arranged so as to enter between the perforated steel plate gibels 21.

Next, a plurality of support pipes 23 for fixing the anchor bolt 3 to the foundation pile 2 are arranged in the outer peripheral steel pipe 20. The support pipe 23 is integrated with a support plate 24 which is welded and fixed to the inner peripheral surface of the outer peripheral steel pipe 20 so as to project in the radial direction. An annular positioning plate 25 fixed to the peripheral surface by welding is integrated.
The support tube 23 is a cylindrical body formed with a diameter that creates a slight gap with the anchor bolt 3. The support plate 24 is a steel plate having a size formed in accordance with the length of the support tube 23, and a hole is formed in a line at a portion protruding in the central axis direction to form a diver. The two upper and lower positioning plates 25 are for positioning the support tube 23 into which the anchor bolt 3 is inserted in order to obtain the positional accuracy of the anchor bolt 3.

  The positioning plate 25 is integrally formed such that the support tube 23 and the support plate 24 are positioned between the perforated steel plate gibber 21, and the perforated steel plate diver 21 is provided on the outer peripheral side which is welded and fixed to the outer peripheral steel tube 20. A notch 25a is formed so as to pass therethrough. The outer vertical stripe 14 passes through the positioning plate 25 through the notch 25a, and the inner vertical stripe 14 passes through the positioning plate 25 by a through hole 25b formed for the vertical stripe 14. . Furthermore, the vertical stripes 13 at positions overlapping the support tube 23 and the support plate 24 are shortened as shown in FIG. 4 so as not to interfere.

  As shown in FIG. 2, the foundation pile 2 is placed as described above. First, a rebar cage in which the vertical bars 11 to 14 are integrated into a cylindrical shape is assembled, and the piles are dug in the pile hole dug into the ground. Built. At that time, the outer peripheral steel pipe 20 in which the perforated steel plate dowel 21, the support pipe 23, the support plate 24, and the positioning plate 25 are integrally formed at the upper part of the pile hole is disposed at the upper end portion constituting the joint part. The anchor bolt 3 is fastened and fixed to the support tube 23 with a nut, and is formed integrally with the outer peripheral steel tube 20. In such a state, the concrete is poured into the pile hole and cast, and the foundation pile 2 is constructed.

  From the foundation pile 2 on which the concrete is cast, anchor bolts 3 project vertically and at equal intervals in the circumferential direction, and the pier base 27 is fixed to the anchor bolts 3 so that the steel pier 1 stands. Established. As shown in FIG. 3, the pier base portion 27 is formed with flange portions 27 a and 27 b at the top and bottom, and a plurality of support plates 27 c are connected therebetween at a predetermined interval in the circumferential direction. Although only one anchor bolt 3 is shown in the drawing, a plurality of anchor bolts 3 pass through the flange portions 27a and 27b and are coupled by tightening nuts at the top and bottom thereof. The steel pier 1 is erected on the foundation pile 2 by such coupling of the pier base 27.

In such a steel pier structure of this embodiment, the steel pier 100 is not erected via the footing 102 as in the conventional example shown in FIG. Since the pier 1 was directly erected, the construction period for footing could be shortened.
The steel pier 1 of this embodiment has a diameter of about 1.8 m and a length of about 5.8 m, for example, and the diameter of the foundation pile 2 that supports the constructed pier 1 and the elevated road 300 (see FIG. 1) is about 3 m. It is. On the other hand, when the steel pier 100 is erected on the footing 106 shown in FIG. 6, for example, nine foundation piles 105 are driven into the ground to construct the elevated road 300 of the same steel pier 1. On the other hand, a footing 102 having a side of 8.5 m square is formed.

  Therefore, compared with driving nine foundation piles 105, in this embodiment, since one foundation pile 2 is stood up as a cast-in-place pile, the construction period can be shortened in this respect as well. Then, by shortening the construction period, when the steel pier 1 is built in the median strip sandwiched between the roads 200 as shown in FIG. Can suppress deterioration of the surrounding environment and economic loss.

  Furthermore, when a plurality of foundation piles 105 are driven over a wide range and the footing 106 is formed over a wide range as in the conventional example, the construction range is expanded accordingly and the regulation range is expanded. On the other hand, in this embodiment, the foundation pile 2 has a large diameter but one cast-in-place pile, and since no footing is required, the range of traffic regulation is narrowed by narrowing the construction area. Can

  By the way, when a roll caused by an earthquake occurs on the steel pier 1 supporting the elevated road 300, the roll is applied as a moment to the foundation pile 2 via the joint between the steel pier 1 and the foundation pile 2. Works. And the moment which acts on the foundation pile 2 will be received in the state where it was spring-supported by the ground which supports the foundation pile 2. The steel pier structure of the present embodiment is configured to effectively transmit the force caused by the rolling generated in the steel pier 1 to the foundation pile 2 in this way.

  When rolling occurs on the steel pier 1, the force is transmitted through the anchor bolt 3 to which the pier base 27 is fixed. Since the anchor bolt 3 is inserted into and integrated with the support pipe 23 on the foundation pile 2 side, the force transmitted through the anchor bolt 3 is transmitted from the support pipe 23 through the support plate 24 to the outer peripheral steel pipe 20. To be told. And since the outer peripheral pipe 20 is integrated with a plurality of perforated steel plate gibels 21 so as to prevent displacement with respect to the concrete of the foundation pile 2, the rolling force transmitted to the outer peripheral steel pipe 20 is further increased. It is transmitted from the perforated steel plate gibel 21 to the foundation pile 20, particularly to the longitudinal bars 11 to 14.

  That is, in the steel pier structure of this embodiment, the structure of the joint part which directly transmits the roll at the steel pier 1 to the foundation pile 2 without using the footing is taken. In this case, simply embedding the anchor bolt 3 in the pile head of the foundation pile 2 cannot secure the resistance area against the pull-out shear of the concrete, but the force is transmitted through the perforated steel plate gibber 21. Therefore, it is possible to secure a resistance area against the pull-out shear of the concrete by preventing the displacement with respect to the concrete. Further, by surrounding the concrete forming the foundation pile 2 with the outer peripheral steel pipe 20, it is possible to improve the strength of the concrete and to increase the shear strength of the perforated steel plate gibber and to omit the band reinforcement. It was.

As mentioned above, although one embodiment was described about the steel pier structure concerning the present invention, and its construction method, the present invention is not limited to this but various changes are possible in the range which does not deviate from the meaning.
In the above-described embodiment, the sway of the steel pier 1 transmitted to the anchor bolt 3 is configured to be transmitted from the support pipe 23 to the support plate 24 and to the perforated steel plate gibber 21 via the outer peripheral steel pipe 20. However, for example, both of them may be connected so as to be transmitted directly from the support tube 23 to the perforated steel plate gibber 21 without going through the outer peripheral steel tube 20.

It is the figure which showed the steel pier structure constructed in the median for passing the elevated road. It is the figure which showed the outline of the construction process about the foundation pile part which comprises a steel pier structure. It is the perspective view which showed the junction part of the steel pier which comprises a steel pier structure, and a foundation pile. It is the figure which showed the AA cross section of FIG. 5 about the junction part of the steel pier and foundation pile which comprise a steel pier structure. It is the figure which showed the BB cross section of FIG. 4 about the junction part of the steel pier and the foundation pile which comprise a steel pier structure. It is sectional drawing which showed the junction part of the steel pier structure using a footing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel bridge pier 2 Foundation pile 3 Anchor bolt 11-14 Longitudinal reinforcement 20 Peripheral steel pipe 21 Perforated steel plate gibel 23 Support pipe 24 Support plate 25 Positioning plate 27 Pier base

Claims (6)

In a steel pier structure in which steel piers are erected and supported by foundation piles buried in the ground,
A cast-in-place pile formed by digging a ground into a pile hole dug into the ground and placing concrete into a foundation pile, and connecting the base of the pier to the anchor bolt protruding from the upper end of the steel The bridge pier is erected on the foundation pile.
In the pile head of the foundation pile, a plurality of support members supporting the perforated steel plate gibel and the anchor bolts in the concrete are arranged in the circumferential direction together with the longitudinal bars of the reinforcing steel cage, and from the steel pier A steel pier structure in which a support member and a perforated steel plate dowel are connected so that a force transmitted to an anchor bolt is further transmitted to a perforated steel plate dowel. In the steel pier structure according to claim 1,
A steel pier structure, wherein the foundation pile has a pile head covered with an outer peripheral steel pipe, and the perforated steel plate gibel and the support member are fixed to the outer peripheral steel pipe. In the steel pier structure according to claim 2,
The support member is a support tube for inserting and fixing the anchor bolt, and the support tube is fixed to the inner peripheral surface of the outer peripheral steel tube by a support plate that is integrally formed by projecting in the radial direction. The steel pier structure characterized by being. In the steel pier structure according to claim 3,
The support plate of the support member projects further from the support pipe in the direction of the center axis of the foundation pile, and a plurality of holes are formed in the projecting portion to form a gibber. In the steel pier structure according to claim 3 or claim 4,
An annular positioning plate is fixed to the inner peripheral surface of the outer peripheral steel pipe, and the support pipe is integrally fixed to the positioning plate in advance, and the support pipe is positioned by fixing the positioning plate to the outer peripheral steel pipe. A steel pier structure characterized by being made as described above. In the construction method of the steel pier structure that is formed by connecting the steel pier to the foundation pile buried in the ground,
A step of rotating and pressing the casing into the ground by a tubing device, and excavating the soil in the casing;
A process of building a reinforcing steel cage in a pile hole dug into the casing;
The perforated steel sheet so that a plurality of perforated steel plate gibels and supporting members for supporting the anchor bolts are arranged in the circumferential direction along with the vertical bars of the reinforcing steel cage at the top of the pile hole that becomes the pile head of the foundation pile. A step of arranging an outer peripheral steel pipe in which the gibber and the support member are integrally fixed;
The process of building foundation piles by cast-in-place piles made by pouring concrete into the pile holes;
The construction of a steel pier structure comprising a step of connecting a pier base to an anchor bolt projecting from a pile head of the foundation pile and standing a steel pier on the foundation pile. Method.

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