JPH0453685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to a precast concrete member having a U-shaped cross section for use in buildings, and a molding frame for forming the same by centrifugal molding.

<<Conventional technology>> Traditionally, when constructing buildings, precast concrete has often been used not only for wall materials but also for beam members and column members, making it easier to assemble and dismantle formwork at the construction site. There is a construction method that aims to reduce the amount of damage and thereby shorten the construction period as much as possible. In other words, in this construction method, beam members made of precast concrete formed in the shape of a channel with a U-shaped cross section, and pillar members made of precast concrete formed in the shape of a cylinder with a rectangular cross section are manufactured in advance in a factory, etc. After these precast concrete beam members and column members are fixed in a predetermined position at the construction site, concrete is placed inside them to form them solidly.

The precast concrete beam members used in this construction method are made by overlapping two large and small outer formwork and inner formwork with a U-shaped cross section with a predetermined space between them. Pour fresh concrete into the container and form it.

<Problems to be Solved by the Invention> By the way, when a precast concrete beam member is manufactured by the conventional method as described above, it becomes difficult to reduce the manufacturing cost, and there are problems in that the quality of the concrete is inferior to that of a member made by centrifugal forming. It was hot.

In addition, as a device that can centrifugally form a channel-shaped precast concrete member with a U-shaped cross section,
For example, a proposal such as Japanese Patent Publication No. 56-50846 has become publicly known, but the centrifugal forming apparatus shown in this proposal is suitable for manufacturing small precast concrete members such as U-shaped grooves. However, it was not suitable for centrifugal forming of long columns and beams, as the forming equipment became too large.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a precast concrete member having a U-shaped cross section with good workability, and a molding frame for manufacturing the same by centrifugal molding. The aim is to provide the following at a low price.

<<Means for Solving the Problems>> The present invention provides precast concrete formed by centrifugal forming into a U-shaped cross section having two sides facing each other at a distance and one side connecting these two sides. In the manufactured member, shear reinforcing bars are provided in the thick wall portion having a U-shaped cross section and are arranged along the cross section and project outward from the edges of each of the two opposing sides. Configure.

Furthermore, the present invention provides a molding frame for centrifugally forming a precast concrete member having a U-shaped cross section. an outer formwork to be driven; an inner formwork provided along the axial direction within the outer formwork to define a centrifugal molding space with an annular cross section between the outer formwork; and an inner formwork. It is arranged along the axial direction in the centrifugal molding space defined by the outer mold and the outer mold, and is provided in close contact with two opposing inner wall surfaces of the outer mold to partition the molding space into two. It is composed of a border material.

<<Function>> The precast concrete member having the above structure is configured so that shear reinforcement is already installed in the thick part of the member during the centrifugal forming stage, and the member itself is Not only can it be manufactured with high rigidity, but it can also be made thinner and lighter. In addition, the reinforcement work on site can be reduced and construction can be simplified. In addition, since the shear reinforcing bars are placed during manufacturing, the reinforcement can be placed more accurately than on-site.

According to the centrifugal molding form having the above configuration, the centrifugal molding space having an annular cross section defined by the outer mold and the inner mold is divided into two along the axial direction by the edging material. When fresh concrete is placed in a form and centrifugally formed, two groove-shaped precast concrete members with a U-shaped cross section are obtained. In addition, for the outer formwork and the inner formwork, the formwork for cylindrical members with a rectangular cross section manufactured by centrifugal molding can be used as is.
Since all that is required is to attach edge materials to this, centrifugal molding forms for precast concrete members can be provided at low cost.

<<Example>> Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

Fig. 1 is a cross-sectional view of a forming form for centrifugally forming precast concrete members, Fig. 2 is a perspective view of the forming form, and Fig. 3 is the forming form and the device for rotating it. FIG.

As shown in Figs. 1 to 3, the centrifugal molding frame 2
A cylindrical outer form 4 having a rectangular cross section and a predetermined length, and a cross section provided close to four corners 4a in this outer form 4. It mainly consists of a right-angled triangular inner handle frame 6 and edge trimming members 8 provided in close contact with the opposing inner wall surfaces of the outer frame 4.

The inner formwork 6 is disposed such that its vertical apex 6a faces each corner 4a of the outer formwork 4.
The outer formwork 4 and each inner formwork 6, . . . are connected to each other by end plates 10 at both ends in the longitudinal direction, and the internal space corresponding to the cross section of the member is closed by the end plates 10. There is.

Further, two rotary drive discs 12, 12 are attached to the outer circumferential side of the outer form frame 4, and these rotary drive discs 12, 12 are connected to the drive side drum 16 and driven side drum 18 of the rotation drive device 14. placed above;
It is adapted to be rotated around the axis of the outer formwork 4. Although not shown, a ready-mixed concrete supply pipe is rotatably attached to the end plate 10 in alignment with the axis of the outer formwork 4, although this supply pipe is not shown. Fresh concrete is supplied from a concrete pump into the outer formwork 4 through the concrete pump.

Furthermore, the edge trimming material 8 has a rectangular parallelepiped shape and forms a long side portion of a rectangle in cross section, and two of the opposing outer formworks 4 are formed.
The two inner wall surfaces 4b, 4b are disposed in close contact approximately at the center along the axial direction. The edge material 8 is made of, for example, styrofoam.

Therefore, the centrifugal molding frame 2 made in this way
is placed on the rotary drive device 14 and poured into the centrifugal forming form 2 while rotating. When the ready-mixed concrete is poured into the inner formwork 6 and the inner formwork 4 by centrifugal force, The water is filled into the centrifugal molding space between the outer formwork 4 and formed into a layer with a substantially uniform thickness while being pressed against the inner circumferential wall surface of the outer formwork 4, and excess water contained inside is discharged by centrifugal force. It is gradually being tightened.

At this time, since the centrifugal molding space defined by the outer formwork 4 and the inner formwork 6 is divided into two along the axial direction by the edge material 8, the resulting groove has a U-shaped cross section. High quality precast concrete member 20 of the mold 2
The body will be manufactured at the same time.

This precast concrete member 20 is
By centrifugal molding, it is formed into a U-shaped cross section with two opposing sides spaced apart from each other and one side connecting these two sides. Shear reinforcing bars 22 are provided along the surface shape and protrude outward from the edges of each of two opposing sides.

The precast concrete member 20 manufactured in this way can of course be used for the bottom formwork of beam materials.
It can be used for pillar materials where pillars and walls connect.

Reference numeral 22 shown in FIG. 1 indicates shear reinforcing bars, and the shear reinforcing bars 22 are annular and are embedded in large numbers at appropriate intervals in the axial direction within each of the left and right members 20, 20 shown. There is. The shear reinforcing bars 22 are partially exposed on the open side of the members 20, 20 having a U-shaped cross section, and the shear reinforcing bars 22 are partially exposed on the open side of the members 20, 20 having a U-shaped cross section.
2 are arranged alternately along the axial direction.

The precast concrete member 20 configured in this manner is configured such that the shear reinforcing bars 22 are already installed in the centrifugal forming stage so that the shear reinforcing bars 22 are provided in the thick part of the member. 20 itself can be manufactured with high rigidity, and this also allows the wall thickness to be reduced and weight reduction to be achieved.
In addition, the reinforcement work on site can be reduced and construction can be simplified. Also, during manufacturing, shear reinforcing bars 2
2, the reinforcement can be placed more accurately than on-site reinforcement.

<<Effects>> In summary, according to the present invention, the following excellent effects are exhibited.

(1) The structure is such that the shear reinforcement is already installed at the centrifugal molding stage so that the shear reinforcement is installed in the thick wall part, and the part itself can be manufactured with high rigidity, and this also allows the wall thickness to be increased. It is also possible to reduce the weight by making it thinner. In addition, the reinforcement work on site can be reduced and construction can be simplified. In addition, since the shear reinforcing bars are placed during manufacturing, the reinforcement can be placed more accurately than on-site.

(2) The centrifugal molding space, which has an annular cross section defined by the outer formwork and the inner formwork, is divided into two along the axial direction by edge cutting materials, and is made of precast concrete with a U-shaped cross section. Since the parts constitute a centrifugal molding form, the formwork for a cylindrical member with a rectangular cross section manufactured by centrifugal molding can be used as is to create a centrifugal mold for a precast concrete member with a U-shaped cross section. We can provide frames at low prices. In addition, by pouring fresh concrete into this centrifugal forming form and centrifugally forming a channel-shaped precast concrete member with a U-shaped cross section, it is possible to create two members at the same time, increasing production efficiency. In addition, it is possible to manufacture high-quality precast concrete members.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a centrifugal forming form for a precast concrete member according to the present invention and a precast concrete member manufactured thereby, and FIG. 2 is a perspective view of the entire centrifugal forming form.
FIG. 3 is a front view showing this centrifugal molding frame and a rotation drive device for rotationally driving the centrifugal molding frame. 2...Centrifugal molding formwork, 4...Outer formwork, 6...Inner formwork, 8...Edge material, 14...Rotary drive device,
20... Precast concrete member, 22
...Shear reinforcement.

Claims (1)

[Scope of Claims] 1. In a precast concrete member formed by centrifugal forming into a U-shaped cross section having two opposing sides spaced apart from each other and one side connecting these two sides, the above-mentioned cross section A plate characterized in that shear reinforcing bars are provided in the U-shaped thick wall portion along its cross-sectional shape and protrude outward from the edges of each of the two opposing sides. Cast concrete components. 2 In a forming form for centrifugally forming a precast concrete member with a U-shaped cross section, the cross section is rectangular and cylindrical, and the outside is driven to rotate around the axis of the cylinder. a mold; an inner mold that is provided along the axial direction within the outer mold and defines a centrifugal molding space with an annular cross section between the outer mold; the inner mold and the outer mold; an edge that is disposed along the axial direction within the centrifugal molding space defined by the frame, and that is provided in close contact with two opposing inner wall surfaces of the outer mold frame and partitions the molding space into two; A centrifugal forming formwork for precast concrete members, characterized by comprising a girder and the following.