JP2842179B2 - Method of reducing lateral pressure on formwork due to concrete casting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing lateral pressure applied to a formwork during concrete casting.

[0002]

2. Description of the Related Art With the recent development of concrete technology,
For example, superfluid concrete having excellent fluidity and excellent workability has been developed. Such superfluid concrete is a highly fluid concrete having a slump value of 25 cm or more, and is obtained by appropriately selecting and blending a commercially available material. It is represented by the product name Neurocrete (manufactured by Obayashi Corp.), which has rich properties. According to this super-fluidized concrete, it can be filled without compaction even in places where reinforcements are dense, and it has excellent pumping properties. It is difficult to construct concrete and RC or PRC structures and RC structures with relatively thin walls, which are considered to be difficult to install. It can be performed.

[0003] However, the above superfluid concrete has the above-mentioned advantages, but because of its high fluidity, an excessive lateral pressure is applied to the formwork on which the superfluid concrete is cast as compared with ordinary concrete. . That is, as shown in FIG. 4, the lateral pressure due to superfluid concrete has a triangular distribution equivalent to the liquid pressure, which is greater than the lateral pressure due to normal concrete indicated by the wavy line in FIG.
Therefore, particularly when the finished height of the structure to be constructed is high, an excessive load is applied to the form by the side pressure applied thereto, and a problem occurs in the safety of the assembled form. .

[0004] On the other hand, in the case of ordinary concrete, when the finishing height of the structure to be constructed is high, an excessive load is similarly applied to the form by lateral pressure.

[0005] In order to cope with such a large lateral pressure, for example, a method of increasing the rigidity of the form to the extent that it can withstand the lateral pressure, or shortening the setting time by blending a setting accelerator into the concrete to be poured. There is a way to do it.

[0006]

However, in the above method of increasing the rigidity of the mold, a large amount of labor is required for installation and removal of the mold due to an increase in the weight of the mold, and the material cost of the mold is increased. There was a problem that would be bulky. In addition, in the method in which a setting accelerator is blended into the concrete to be poured, it is difficult to control the setting time of the superfluid concrete by the setting accelerator when casting superfluid concrete. There is a risk that the operation of placing concrete utilizing the properties of superfluid concrete will be hindered because the fluidity of superfluid concrete is impaired by compounding the agent, while when placing ordinary concrete, Since the curing is started early, there is a problem that the time from the production of the concrete to the casting is limited.

Therefore, the present invention has been made in view of the above-mentioned problems, and the side pressure acting on the formwork by casting concrete is easily and easily reduced to improve the safety of the assembled formwork. It is an object of the present invention to provide a method of reducing lateral pressure on a formwork associated with concrete placing, which can achieve the following.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and a gist of the invention is a method for reducing lateral pressure applied to a formwork during concrete casting. The method for reducing the lateral pressure on the formwork accompanying the concrete placement is characterized in that the concrete is placed while being heated immediately after the concrete is put into the formwork.

Further, according to the method of reducing lateral pressure on a formwork accompanying concrete casting according to the present invention, the concrete is heated immediately after being poured by using a form supporting member which is provided with a number of separators installed in the form. It is preferable that the heat generation be performed.

Further, the concrete immediately after the casting can be heated by generating heat in the form to which the lateral pressure is applied.

[0011]

According to the method for reducing lateral pressure on a formwork accompanying concrete casting according to the present invention, the concrete is heated immediately after being poured, thereby promoting the setting of the concrete and enhancing its self-sustainability. To reduce the lateral pressure acting on

In addition, if the heating of the concrete is carried out by heating a separator which is conventionally used as a form supporting member during the assembly of the form or by heating the form itself, the concrete can be heated at the time of assembling the form. It is possible to easily promote the setting of superfluid concrete and reduce the lateral pressure applied to the formwork without impairing the workability.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a situation in which superfluid concrete C is used as concrete and cast into a formwork 10 via a casting pipe 12 in order to construct a wall-shaped concrete structure. is there.

The formwork 10 includes frame plates 20, 20 and a plurality of separators as formwork support members provided in the formwork 10 for holding and fixing the space between the frame plates 20, 20 at a predetermined distance. 11. In FIG. 1, a form fixing member such as a vertical end or a horizontal end for supporting the form 10 from the outside of the frame plates 20, 20 is attached to the form 10 for convenience. It is abbreviated.

In the method for reducing the lateral pressure on the formwork accompanying concrete casting according to this embodiment, the superfluid concrete C immediately after being poured is heated by using a large number of separators 11 arranged in the formwork 10. I do.

Here, the separator 11 is formed by the frame plates 20 and 2.
0 Designed appropriately, for example, 5
At intervals of 0 cm, 100 cm, etc., a large number of molds 10 are arranged in rows in the horizontal and vertical directions uniformly over the entire formwork 10. As shown in FIG. For example, the separator main body 13 having the male screw portions 11a formed at both ends thereof and being in contact with the inner surface of the frame plate 20 in a state where the separator main body 13 is attached to the frame plate 20. As separator body 1
3 and a nut screwed into the male screw portion 11a protruding from the frame plate 20 in a state where the male screw portion 11a is inserted through the mounting hole 20a formed in the frame plate 20. 14. Then, in a state where both ends of the separator body 13 are inserted into the mounting holes 20a of the frame plate 20 and the cone 16 is in contact with the inner surface of the frame plate 20,
By fastening the nut 14 from the outside of the frame plate 20, the frame plate 20 is clamped from the front and back by the nut 14 and the cone 16 and fixed.

Further, this separator 11 is formed as shown in FIG.
As shown in (b), the inside is hollow, and the hot wire coil 15 is disposed in the hollow part. The heating wire coil 15 is a spiral heating wire such as a coated nichrome wire, is sealed in the separator 11, and is connected to an electricity supply device provided outside the formwork 10 via a connection cord 15a. The separator 11 is heated by generating heat by the operation of the apparatus. The thickness of the separator 11 can be adjusted to compensate for a decrease in tensile strength due to the hollow cross section.

According to the form 10 having such a configuration, the form 10 is formed by the superfluid concrete C that has been cast.
Can be easily reduced. That is, before the superfluid concrete C is charged or immediately after the superfluid concrete C is charged, the heating device is operated to drive the hot wire coil 15, that is, the separator 11, from the separator 11 located below the form 10, for example. The superfluid concrete C around the separator 11 is heated immediately after being charged by sequentially heating according to the installation height to promote the coagulation of the superfluid concrete C to lose its fluidity and to become independent. , Thereby reducing the lateral pressure applied to the frame plate 20. According to this embodiment, since the separator conventionally used as the form supporting member is used as it is, the lateral pressure can be efficiently reduced without impairing the workability at the time of assembling the form.

FIGS. 3 (a) and 3 (b) show another embodiment of the present invention, in which a superfluid concrete C is formed by heating the frame plate 20 itself which forms the formwork 10. FIG.
Is to be heated. That is, FIG.
The frame plate 20 of (a) has a double structure composed of plywoods 21a and 21b, and between the plywoods 21a and 21b, a hot-wire coil 15 connected to an energizing device is vertically and horizontally enclosed and arranged. A heat insulating material 22 for preventing the heat of the hot wire coil 15 from being radiated to the outside is attached to the inner surface of the plywood 21a. On the other hand, the frame plate 20 of FIG.
The plywood 21a has a single-layer structure, and a hot-wire panel 25 made of a heat-insulating plastic 23 and a conductive plastic 24 is disposed on the side of the plywood 21a on which the superfluid concrete C is cast.

According to this embodiment, by heating the frame plate 20, the superfluid concrete C immediately after being put in the vicinity of the frame plate 20 is heated, and the same as in the above-described embodiment. Thus, the lateral pressure applied to the frame plate 20 can be easily reduced by promoting the setting of the overflow concrete C. According to this embodiment, by using the form itself as a heating member as it is, the lateral pressure can be efficiently reduced without impairing the workability at the time of assembling the form. Further, according to this embodiment, in the case of the frame plate 20 of FIG. 3A, the frame plate 20 itself having the hot-wire coil 15 is used, and in the case of the frame plate 20 of FIG.
Can be diverted and used.

In each of the above embodiments, the case where superfluid concrete C is cast into the mold 20 has been described. However, the method for reducing the lateral pressure on the mold according to the concrete casting according to the present invention is described below. It can also be applied to the case where ordinary concrete is cast in the interior.

In each of the above embodiments, by adjusting the voltage applied to the hot wire coil 15, the frame plate 20,
It is also possible to control the amount of reduction of the lateral pressure acting on 20.

Further, as a development example, the present invention can also be used to accelerate the hardening of concrete, for example, in cold regions.

[0024]

As described above, according to the method for reducing lateral pressure on a formwork according to the present invention, concrete is poured by heating concrete immediately after being put into the formwork. Promotes coagulation to increase its independence,
As a result, the lateral pressure acting on the mold is easily and easily reduced, so that the safety of the assembled mold can be easily improved.

Further, if the concrete is heated by heating a separator which is conventionally used as a form supporting member during the assembly of the form or by heating the form itself, the work at the time of assembling the form can be achieved. Without impairing the properties, it is possible to efficiently promote the setting of superfluid concrete and reduce the lateral pressure applied to the formwork.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment in which superfluid concrete is poured into a formwork while adopting the method for reducing lateral pressure on a formwork accompanying concrete placing according to the present invention.

FIGS. 2A and 2B are explanatory views showing the configuration of a separator used in one embodiment of the present invention.

FIGS. 3A and 3B are cross-sectional views of a frame plate constituting a mold used in another embodiment of the present invention.

FIG. 4 shows a distribution of lateral pressure acting on a frame plate when superfluid concrete is poured into a form by a conventional method, and a dashed line shows a distribution of lateral pressure when ordinary concrete is poured. It shows the distribution.

[Explanation of symbols]

 10 Formwork 11 Separator 15 Hot wire coil 20 Frame plate C Superfluid concrete

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noritake Takeda 4-640 Shimoseito, Kiyose-shi, Tokyo Co., Ltd. Inside Obayashi Corporation Technical Research Institute (72) Inventor Takayoshi Hirata 4-640 Shimoseito, Kiyose-shi, Tokyo Co., Ltd. Inside Obayashi Technical Research Institute (72) Inventor Masami Kurihara 4-640 Shimoseito, Kiyose-shi, Tokyo Inside Obayashi Technical Research Institute Co., Ltd. (56) References JP-A-7-102771 (JP, A) JP-A-5-33494 ( JP, A) JP-A-5-133103 (JP, A) JP-A-62-55372 (JP, A) JP-A-61-155553 (JP, U) JP-B-52-8111 (JP, B2) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) E04G 21/02 103

Claims (3)

(57) [Claims] 1. A lateral pressure reducing method for reducing lateral pressure applied to a formwork during concrete casting, wherein concrete is poured while being heated immediately after being put into the formwork. Method of reducing lateral pressure on formwork accompanying concrete casting. 2. The concrete casting method according to claim 1, wherein the concrete immediately after the casting is heated by generating heat from a plurality of separators, which are form supporting members, which are provided in the form. Method to reduce lateral pressure on the formwork. 3. The method according to claim 1, wherein the concrete immediately after the casting is heated by generating heat from the form to which the lateral pressure is applied. Method.