JPH06346471A - Construction of reinforced concrete retaining wall by use of large size precast slab - Google Patents

Abstract

PURPOSE:To improve the workability and quality and reduce the construction period, by oppositely arranging thin PC slabs with distributing bars piercing protruded vertical ribs of the slabs and firmly fixing them separators and placing post-cast concrete between PC slabs. CONSTITUTION:A pair of large size thin PC slabs A having protruded vertical ribs 1 through which distributing bars 2 are arranged horizontally are oppositely erected on a bottom slab as a formwork and a support and fixed firmly with separators. At that time, the PC slab A is used for both formwork and support and concrete is placed therebetween. The distributing bars 2 assembled in the PC slab are used as dowel bars in common and unified with post-cast concrete together with the vertical ribs 1. When the post-cast concrete is placed, the side pressure is supported by the ribs 1 to prevent the deformation and cracks of PC slab A. Moreover, the distance between the separators and the size of rib 1 are adjusted in accordance with the side pressure on placing concrete to correspond thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a reinforced concrete retaining wall using a large precast plate.

[0002]

2. Description of the Related Art Formwork for concrete construction is a dam plate,
It consists of supporting works and its accessories. When constructing a concrete structure with a large area such as a reinforced concrete retaining wall, a large formwork that integrates a weir plate and support is used for the purpose of streamlining the construction.

The dam plate of this large formwork is composed of metal foam or plywood with a special surface finish so that it can be used many times. The large formwork has a larger number of diversions than the ordinary plywood formwork, and is large, and since the weir plate and the support work are integrated into a unit, it is effective for labor saving and rationalization of construction. However, the formwork has an important role of supporting the sound progress of the hydration reaction of concrete, and therefore the formwork cannot be demolded until the concrete strength is sufficiently developed, so that it is possible to use a large formwork. However, it was not possible to shorten the construction period.

Further, in the case of an outdoor structure such as a civil engineering structure, there are many exposed finishes, and it is necessary to place high quality concrete for the purpose of improving durability, and sufficient construction management is required. . Furthermore, recently, civil engineering structures are often designed to have a pattern on the surface from the viewpoint of aesthetics, and quality control of formwork construction has become an increasingly important issue.

7 to 9 show the outline of a conventional method, in which a dam plate c is formed on a bottom slab b on which a main bar a is erected on site.
Is installed and tightened with a separator d, a mold clamping tool, and a support e such as a thick timber, a reinforcing bar f is arranged, concrete is placed in the weir plate c, and the same concrete is placed. When the required strength was developed, the mold was removed and the retaining wall g was constructed. In the figure, h is a joint surface and i is an expansion joint. 10 (a) and 10 (b) show an inverted T-shaped retaining wall and an L-shaped retaining wall which are the subject of the present invention.

[0006]

When constructing a reinforced concrete retaining wall, the large formwork method has a larger area per unit than the conventional method, so that the formwork work is rationalized.
The labor saving of carpenters can be achieved, it does not require a high level of skill because it is a unit, the number of diversions is large,
There are advantages such as.

However, there are the following problems. (B) A work scaffold j for assembling wall distribution bars and for placing concrete is required. (See Fig. 9) (b) The curing period after placing concrete is the same as the conventional method, and the formwork cannot be disassembled until sufficient strength is developed. (C) When a pattern is to be applied to the concrete surface, it is necessary to attach another pattern sheet to the surface of the unit formwork and pour the concrete in the same way as in the conventional construction method, so the on-site work is complicated. (D) For the durability of concrete, careful management is required during construction.

The present invention has been proposed in view of the above problems of the prior art. The object of the present invention is to improve workability by eliminating the work scaffolding for bar arrangement and the work of dismantling the formwork. The point is to provide a method for constructing a reinforced concrete retaining wall using a large precast concrete plate that has been shortened and improved in quality.

[0009]

In order to achieve the above-mentioned object, according to the method for constructing a reinforced concrete retaining wall using a large precast plate according to the present invention, a plurality of longitudinal ribs are provided on the inner surface, A pair of large, thin-walled precast plates, each of which was formed by horizontally piercing and arranging a force-combining muscle that also serves as a gibber across the respective ribs, were placed opposite to each other on the bottom plate, and the opposing precast plates were tightened with a separator. After that, concrete is placed and filled between the precast plates.

[0010]

According to the present invention, since it is configured as described above, one pair of left and right thin-walled precast plates are built on the bottom plate by a crane or the like, and both precast plates are tightly bound by a separator. Concrete is placed using the as a weir plate. At this time, it is possible to perform continuous construction without using support and work scaffolds and without considering the conversion of these.

The plurality of longitudinal ribs projecting from the inner surface of the thin precast plate increases the strength and rigidity of the precast plate, and prevents deformation and cracking of the cast concrete against lateral pressure. . Further, the force distribution bar horizontally penetrating between the vertical ribs in the precast plate is combined with the rib by also serving as a gibber rebar,
The concrete and precast plate are integrated, and the precast plate serves both as a structural material and a formwork, eliminating the need for dismantling work of formwork and support.

[0012]

The present invention will be described below with reference to the illustrated embodiments. A is a large-sized thin-walled precast plate having a U-shaped cross section, and vertical ribs 1 project from the inner surface of the main plate at predetermined intervals. A force distribution muscle 2 that also functions as a gibber muscle is provided that horizontally penetrates through ′. Further, horizontal part pieces 1a are projected at the upper and lower ends of the longitudinal ribs 1 at predetermined intervals, and on the sleeve pieces 1'arranged on both sides of the respective part pieces 1a and the thin precast plate A orthogonally to the main plate. A precast plate joint metal fitting 3 is projected on the end face.

A separator mounting through hole 4 is formed in each of the sleeve pieces 1'on both sides and the horizontal portion 1a of the vertical rib 1. In addition, reference numeral 5 in the drawing denotes a backing plate which is provided so as to protrude outside the lower end portion of the thin precast plate A as required. In the joint metal fitting 3, an umbrella-shaped portion is arranged at the upper end of the vertical rod, and when the upper thin precast plate is laminated on the lower thin precast plate A, the stopper 6 of the same precast plate is fitted to the umbrella-shaped portion, The upper and lower precast plates are spliced together. 7 in the figure
Is a horizontal joint.

B is a bottom slab cast in-situ, and the main bar 8 of the retaining wall
Is erected. (See FIG. 1 (a)) Then, the thin precast plate A on the back surface side is built on the bottom plate B and fixed by the precast plate fixing bolt C,
Next, the thin precast plate A on the front surface side is installed, and the back surface side thin precast plate A and the front surface side thin precast plate A are tightly connected by the separator 9. (See FIG. 1B) After assembling the front and back thin-walled precast plates A in this way,
Post-cast concrete D is placed between both precast plates A to construct a retaining wall. (See FIG. 1C.) When joining the thin precast plate A in the vertical direction,
The back surface thin precast plate A is built up, and then the front surface thin precast plate A is built up and tightly bound by the built-in separator 9. At this time, as shown in FIGS. 5 (a) and (b), by mounting the upper thin precast plate A on the lower thin precast plate A, the latter joint metal fitting 3 causes the upper thin precast plate stopper. 6 and the upper and lower thin precast plates are joined.

The retaining wall is constructed by repeating the above work. In addition, if there is a field yard, the above construction can be performed by a method in which the front and back thin precast plates 1 are tightly bound by a separator 9 to form a unit and the units are stacked. A work scaffold at the time of attaching a separator and at the time of post-casting concrete is required. This scaffold is attached to the precast board A, and the scaffold is used to perform the work described above.

[0016]

According to the present invention, as described above, a pair of large-sized thin-walled precast plates in which vertical ribs are provided in a protruding manner and the distribution muscles are horizontally penetrated across the ribs are formed. As a supporting work, it is installed on the bottom slab oppositely and tightly connected with a separator, the precast plate is used as a formwork, and post-cast concrete is also used as a supporting work to construct a retaining wall to dismantle the formwork and supporting work. Therefore, the construction period can be shortened.

The force distribution bar incorporated in the precast plate also serves as a gibber bar, and in cooperation with the longitudinal ribs, it is integrated with the post-cast concrete. Further, by the rib against the lateral pressure at the time of post-casting concrete placement, deformation of the precast plate, preventing the occurrence of cracks, and further by adjusting the separator spacing and the size of the rib by the lateral pressure at the time of concrete casting Can handle the same side pressure.

Further, since the precast plate is manufactured in a factory, it is built with high strength and high quality and in a state where the drying shrinkage is almost completed, so that the surface cracks of the structure are eliminated and the durability is improved. At the same time, the designed pattern can be attached accurately and easily.

[Brief description of drawings]

1 (a), (b) and (c) are vertical cross-sectional views showing steps of a method for constructing a reinforced concrete retaining wall according to the present invention.

FIG. 2 is a view taken along the line aa in FIG.

FIG. 3 is a bb view of FIG. 1C.

FIG. 4 is a perspective view of a large thin precast plate.

5 (a) and (b) are vertical cross-sectional views showing a step of connecting the upper and lower precast plates.

6 (a) and (b) are side views showing each structural type of the retaining wall constructed by the method of the present invention.

FIG. 7 is a perspective view showing a state of implementation of a conventional method.

FIG. 8 is an elevational view of FIG.

9 is a vertical side view of FIG. 7. FIG.

[Explanation of symbols]

 A Thin precast plate B Bottom plate C Precast plate fixing bolt 1 Longitudinal rib 1'Side pieces on both sides 2 Distribution bar 3 Precast plate fitting hardware 4 Separator mounting through hole 5 Holding plate 6 Stopper 7 Horizontal joint 8 Main bar 9 Separator

Claims (1)

[Claims] 1. A pair of large-sized thin-walled precast plates in which a plurality of vertical ribs are provided on the inner surface of the rib, and through which the distribution muscles that also serve as gibber muscles are horizontally penetrated and arranged. A method of constructing a reinforced concrete retaining wall using a large precast plate characterized by placing it above and tightening the opposing precast plates with a separator, then placing and filling concrete between the precast plates. .