JPS639508A - Manufacture of steel-pipe concrete composite pile with diameter expanding section - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a steel pipe-concrete composite pile having an enlarged diameter section.

[Problem that the invention seeks to solve]

In recent years, in the design of pile foundations, the upper pile section, where horizontal force mainly acts, is made of steel pipe concrete pile, and the upper pile section, where horizontal force mainly acts, is made of large-diameter prestressed concrete or other concrete. There is a proposal to use a composite pile consisting of piles. (1976-
No. 154504) This type of composite pile has a large vertical bearing capacity in the upper pile part with a large diameter, and a large bending capacity in the steel pipe concrete pile in the upper pile part, and the pile as a whole has a well-balanced and excellent bearing capacity. Demonstrate. However, this composite pile consists of a steel pipe concrete pile section and a concrete pile section with an enlarged diameter, and could not be made by centrifugal forming within a conventional formwork.

This invention was made in view of the above circumstances. The purpose is to propose a manufacturing method that can efficiently manufacture a steel pipe concrete IJ-to composite pile having an enlarged diameter portion using a formwork having a circular cross section.

[Means and Examples for Solving Problems] This method of manufacturing a steel pipe concrete composite pile having an enlarged diameter section involves installing a steel pipe with a smaller diameter than the inner diameter of the formwork at one end of a formwork with a circular cross section through a spacer. The steel pipe is fixed concentrically, and at the same time, a partition plate is placed between the circumferential surface of the inner end of the steel pipe and the inner surface of the formwork, and concrete is injected into the formwork inside the partition plate and into the steel pipe to perform centrifugal forming. shall be.

Hereinafter, examples will be given and explained using drawings.

In Fig. 1, a steel pipe 2 with an outer diameter of 500 mm and a length of 5 m is fixed concentrically with the formwork 1 through a spacer 3 on one end side of a formwork 1 with a circular cross section for piles with a diameter of 600 mmφ and a length of 15rn. do. At the same time, the gap between the peripheral surface of the inner end of the formwork of the steel pipe 2 and the inner surface of the formwork 1 is made into a trumpet shape.

Alternatively, a partition plate 4 consisting of two semicircular bodies is arranged and partitioned. In addition, donut-shaped end fittings 6, 6' are arranged at the end of the steel pipe 2 and the other end of the formwork 1, and both ends of the reinforcing bar basket 5 arranged in the formwork 1 are connected to the end fittings 6, 6'. , 61. Next, after introducing tension into the reinforcing bar cage 5 as shown in FIG. 2, concrete is injected into the formwork 1 inside the partition plate 4 and across the steel pipe 2, and the formwork 1 is rotated to perform centrifugal forming.

To introduce prestress into the reinforcing bar basket 5 as shown in FIG. 2, for example, the apparatus described in Japanese Utility Model Publication No. 51-48816 is used.

That is, the end fitting 6 at the side end of the steel pipe 2 is locked to a fixed plate 9 disposed in contact with the outside end of the formwork, and the end fitting 61 at the other end is fixed to a donut-shaped movable plate 1゛0 having approximately the same diameter as this. Connect to. The reaction member 11 is brought into contact with a support flange 13 extending outside the end of the formwork 1 to lock the formwork 1, and the movable plate 10 is pulled by a tension rod 12 to apply tension to the reinforcing bar cage 5. In this state, a fixed ring 14 is interposed between the peripheral edge of the mold frame 1 and the peripheral edge of the movable plate 10 to lock and fix the movable plate 10 to the mold frame 1. The movable plate 10 has locking protrusions at predetermined intervals on its periphery, and the inner circumferential edge of the annular fixed ring 14 also has corresponding locking protrusions.
When towing, the movable plate 10 and the fixed ring 14 mutually shift their locking protrusions to allow the movable plate 10 to pass through the internal space of the fixed ring 14, and after towing, the fixed ring 14 is rotated and locked. The protrusions are engaged and locked.

After that, after curing is completed, the pedestal is removed from the mold by passing a wire through the space formed by the spacer 3 between the formwork 1 and the steel pipe 2. The demolded compact is cured in an autoclave to obtain a composite pile.

Figure 2 shows this composite pile, with the upper pile having an outer diameter of 600 mm.
Tomo, the hollow concrete pile part 7 has a length of 10,771 mm, and the upper pile part consists of a hollow steel pipe concrete pile part 8 with an outer diameter of 500 myn and a length of 5 m, and prestress is introduced between the end fittings 6 and 61. A reinforcing bar cage 5 is arranged.

In this embodiment, the partition plate 4 is attached to the inner surface of the formwork 1, and an arbitrary attachment position on the inner surface of the formwork can be selected depending on the length of the steel pipe 2. Further, the outer diameter of the concrete pile portion is preferably larger than the outer diameter of the steel pipe concrete pile portion by at least 50 mm, particularly by at least 1 Q Omm.

In order to ensure strong adhesion between the steel pipe and concrete, there are methods of adding an expanding agent to the concrete or providing ribs or the like protruding from the steel pipe.

〔Effect of the invention〕

This invention is as described above. According to this manufacturing method, a steel pipe-concrete composite pile with an enlarged diameter portion can be manufactured using a conventional formwork with a circular cross section and in accordance with the conventional manufacturing method. Therefore, when manufacturing by using special formwork or by welding the steel pipe concrete pile part and the concrete pile part (compared to this method, it is possible to streamline the work and reduce costs).

[Brief explanation of drawings]

The drawings show examples, and FIGS. 1 and 2 are cross-sectional views of the formwork before and after introducing prestress into the reinforcing bar cage, and FIG. 3 is a cross-sectional view of the obtained composite pile. 1. Formwork, 2. Steel pipe, 3. Spacer, 4. Partition plate, 5. Rebar, 6.6'... End fitting, 7.
・Concrete pile section, 8. Steel pipe concrete pile section, 9. Fixed plate, 10. Movable plate, 11. Fist reaction member, 12. Tension rod, 13. Support shoulder, 14φ
・Fixed ring.

Claims (3)

[Claims] (1) A steel pipe with a diameter smaller than the inner diameter of the formwork is fixed concentrically to one end of a formwork with a circular cross section via a spacer, and at the same time a partition plate is placed between the circumferential surface of the inner end of the steel pipe and the inner surface of the formwork. A method for manufacturing a steel pipe concrete composite pile having an enlarged diameter section, characterized in that concrete is injected into the formwork inside the partition, the partition plate, and the steel pipe, and then centrifugally formed. (2) A method for manufacturing a steel pipe-concrete composite pile having an enlarged diameter portion as set forth in claim 1, which comprises arranging reinforcing bars within the formwork prior to pouring concrete. (3) A method for manufacturing a steel pipe-concrete composite pile having an enlarged diameter portion according to claim 2, which comprises tensioning the reinforcing bars and introducing prestress.