JPH05321229A - Method for constructing top overhung part of concrete dam - Google Patents

Abstract

PURPOSE:To omit provision of a bracket scaffold and timbering by constructing a top overhung part of a dam with placing of the top concrete using a precast concrete block which serves also as a form for concreting. CONSTITUTION:When the next concrete placing is for the top overhang, a frame is erected inside of the form, and in the upper part of the frame is installed an installation pedestal for a precast concrete block which serves also as a form for placing the next top concrete. Then concrete 17 is placed, and upon its hardening, a precast concrete block 18 in approx. L-form is inserted in a bolt groove 19 at a hole provided at the bottom and is secured by a nut 20. This L-form block 18 is of RC or PC structure so that stability is ensured against a shearing force and a flexural moment due to the weight of the concrete to be placed thereon. Finally, concrete is placed to form the top overhung part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a concrete dam, and more particularly to a method of constructing a top end overhang on a dam dam body.

[0002]

2. Description of the Related Art Conventionally, the width of dam dams has only to be wide enough to stop water, and therefore the width of the upper part of the dam is rather narrow so that cars and people can pass through it, and therefore, it is overhanging at the top of the dam. A section is provided to secure a sufficient road width above the dam. As an example thereof, as shown in FIG. 8, an anchor bar 2 in which bracket scaffolds 1 are embedded in concrete at predetermined intervals on the overhanging side that is the dam upstream surface and / or downstream surface of the dam body 3 to which concrete has been spliced Fixed by. The bracket scaffolds 1 are assembled vertically and horizontally by a horizontal cross member 4. Further, the crank-shaped projecting frame 6 forming the concrete overhanging portion 5 on the bank body 3 is entirely covered by a beam girder 8 or the like which connects the horizontal member 4 with the bellows 7 installed laterally on the back thereof. Support as support work. The formwork 6 has columns 9, 1 provided on the concrete overhanging portion 5 side inside the bank.
Tensile members 11 are arranged from 0 to reinforce during concrete pouring.

[0003]

However, in the conventional construction of the above-mentioned top end projecting portion, the following problems are required: that is, it is necessary to install the bracket scaffolds on the upstream and downstream surfaces and then install the formwork. However, this work is at a high place and is not preferable for safety, and after concrete hardening,
Formwork, supporting work and bracket scaffolding had to be removed, and this work was not only dangerous, but there was also the problem that it was extremely complicated and time-consuming due to the overhang structure.

An object of the present invention is to solve the above-mentioned problems, and to provide a method for constructing a concrete dam top end overhanging portion which is a safe and simple operation without performing complicated operations such as installation of bracket scaffolds and supporting works. It will be provided. Another object of the present invention is not only to install bracket scaffolds and support works, but also to eliminate the removal work, shorten the construction period, and construct a dam top end overhanging part with a beautiful appearance.

[0005]

The present invention has been made in view of the above object, and its gist is to install an installation pedestal provided with an anchor material on a bank inside a formwork, and to install the installation pedestal. Up to the first step of placing concrete, the second step of fixing the precast concrete block overhanging from the bank on the installation pedestal with the anchor material, and the precast concrete block as a formwork inside the It is a method of constructing a top portion of a concrete dam that consists of a third step of placing concrete. Here, the installation pedestal provided with the anchor material is preferably made of metal in terms of accuracy in which the precast concrete block to be the mold is aligned, but it is not necessarily limited to metal as long as the accuracy can be obtained. Further, the installation pedestal may be on a set of steel materials on the bank, on a wag, or temporarily fixed to the form, as long as the fixing position is firm, the means is not limited. The precast concrete block can be stably held as a form by providing a tension member on the concrete pouring side of the top end.

[0006]

[Operation] An anchor that fixes a precast concrete block that also serves as a mold for concrete pouring at the top, which will be described later, before the dam body is constructed with concrete and before the top overhang is cast with concrete. Supporting an installation pedestal equipped with materials, concrete is cast and hardened to the installation pedestal, and after fixing the precast concrete block to the installation pedestal, the top end of the dam that is the overhanging part is cast with concrete and precast concrete Finish with the block.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

When the next concrete pouring in the dam body 12 is for overhanging the top of the dam, the formwork 13 that rises and joins from below is arranged around the upper portion of the dam body 12, and the concrete is A pedestal 14 is assembled with an L-shaped steel material inside the formwork 13 to be placed, and an installation pedestal 15 of a precast concrete block to be the next top-end concrete placement formwork is continuously provided along the formwork 13 on the pedestal top. Install. On the mounting base 15, a bolt groove 19 is projected on the base, and an anchor bolt 16 as an anchor material having a fishing anchor portion is arranged under the base. Moreover, if the end of the mounting pedestal 15 is supported on the formwork 13 side in order to accurately fix the precast concrete block, the positioning becomes stable (FIG. 1).

Next, inside the formwork 13, the installation base 15 is installed.
Concrete 17 is poured to the horizontal position of, the bolt groove of the anchor bolt 16 is projected onto the installation pedestal 15, and the formwork 13 is removed.

After the concrete 17 is hardened, the substantially L-shaped precast concrete block 18 is passed through the bolt groove 19 in the hole provided at the bottom of the precast concrete block 18 and the nut 2
Fixed by 0. This precast concrete block 18 is of RC or PC structure and has a stable structure against bending moment and shearing force due to the weight of the concrete placed thereon, and this block 18 extends along the upstream and downstream faces of the dam. It is continuous without a gap. In addition, a hook 21 is attached to the inside of each precast concrete block 18, and a reinforcing bar 23 is tensioned between anchor bars 22 partially embedded in the concrete 17 to make the block 18
Is not inclined to the outside of the bank.

In this way, after the precast concrete block 18 is installed, concrete is cast as the top overhanging portion to finish it.

A plan view of the precast concrete block is shown in FIG. 4, and a sectional view taken along the line AA of FIG. 4 is shown in FIG. The plan view of the installation pedestal is shown in FIG.
The sectional view taken along line B is as shown in FIG.

Further, although the precast concrete block in the above embodiment has the function of a form, it is not considered structurally as a part of the dam body. That is, the overhanging portion is reinforced with reinforcing bars, and it is not necessary to integrate the precast block itself with the dam body, but this is equipped with a dowel to prevent falling.

[0014]

As described above, according to the present invention, the mounting pedestal is attached to the dam body, and the precast concrete block is fixed to the pedestal to form a mold for the concrete dam top end overhanging portion. It is possible to omit work in high places such as support work, installation of the formwork, and removal, and therefore it is possible to obtain the effects of ensuring safety, shortening the construction period, and saving labor.

[Brief description of drawings]

FIG. 1 is a side view showing a state in which an installation pedestal of a precast concrete block in the construction of a concrete dam top end overhanging portion according to the present invention is fixed on a dam body.

FIG. 2 is a side view showing a state where concrete is cast up to an installation pedestal in FIG. 1 and a precast concrete block is fixed on the pedestal.

FIG. 3 is a side view of a precast concrete block in which a sibel is provided inside.

FIG. 4 is a plan view of a precast concrete block.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is a plan view of an installation base.

7 is a sectional view taken along line BB of FIG.

[Fig. 8] Scaffolding of the conventional concrete dam top extension,
It is a side view of formwork support work.

[Explanation of symbols]

 15 Installation pedestal 16 Anchor material 17 Concrete 18 Precast concrete block (form)

Claims (1)

[Claims] 1. A first step of installing an installation pedestal provided with an anchor material on a dam body inside a formwork, and placing concrete up to the installation pedestal, and a bank on the installation pedestal with the anchor material. A method for constructing a concrete dam top end overhanging portion, which comprises a second step of fixing a precast concrete block protruding from the body and a third step of placing concrete inside the precast concrete block as a formwork.