JPH0893101A - Light weight placing form panel - Google Patents

Abstract

PURPOSE: To obtain an inexpensive, light, and high strength placing form panel, by embedding the lower chord members of a truss reinforcements constituted of upper chords, lower chords and diagonal members in a fiber reinforced cement board with a specified thickness. CONSTITUTION: In a form panel for placing concrete forming the surface of concrete after it has been placed, the lower chord members of a truss reinforcements composed of the upper chords, the lower chords, and diagonal members are embedded in a fiber reinforced cement board having 15mm or more and 50mm or less in the thickness. The height of the truss reinforcements is designed to be within 100-350mm and the gross weight of panel is designed to be 120kg or less per unit cubic meter. Recessed grooves and protruded parts are provided at the ends of fiber reinforced cement board to fit adjacent panels. And further, in this case, the adjacent panels are firmly bonded together by use of an adhesive, a sheet material, etc.

Description

Detailed Description of the Invention

[0001]

[Industrial field of use] Currently, cast-in-place concrete structures are widely used in both civil engineering and construction. In that case, a South Sea plywood formwork is widely used as a formwork, and the amount is a huge amount of about 200 million m ² per year. Therefore, recently, from the standpoint of forest resource protection, there has been a movement to reduce plywood formwork in various fields centering on government agencies, and various formwork construction methods have been proposed. Some of them simply replace the plywood with another material, while others radically change the construction method. There is a driving formwork method as a method to radically change the construction method, but this method has recently attracted attention as a future-proof construction method in terms of saving labor on site and shortening the construction period in addition to protecting forest resources. Have begun.

The present invention provides a high-strength, light-weight formwork panel that meets the needs of protecting forest resources and saving labor in the field under such construction and civil engineering conditions.

[0003]

2. Description of the Related Art As a driving form panel, truss-shaped reinforcing bars such as omnier and Kaiser reinforcing bars having a thickness of 60 to 80 m.
There are omnier boards or Kaiser boards buried in m concrete boards, which are mainly used for the floors of buildings.

[0004]

However, these Omnia boards or Kaiser boards have a weight of 13 per m ^2.
Since it is 0 to 200 kg, it is impossible to construct without using a crane. Especially in places where the crane cannot be used, such as narrow valleys in mountainous areas, slopes, or in tunnels, this heavy weight is fatal.

The present invention solves the problem that the existing Omnia plate and Kaiser plate are heavy, and provides an inexpensive, lightweight and high strength driving form panel. The weight of the driving form panel according to the present invention is as light as 120 kg or less per 1 m ² , and when the crane cannot be used in mountainous areas etc., if the panel split is divided into about 1 m ^{2 each} , it will be lightweight up to around 50 kg per one. It is possible to make it possible, and it can be constructed only by human power without using a crane.

When the mortar is reinforced with fibers, the strength is 2 to
It is well known that the wall thickness of the fiber reinforced cement board can be reduced to 1/2 to 1/10 of that of ordinary concrete and can be reduced in weight because it increases 10 times. In particular, GRC (glass fiber reinforced cement) reinforced with zirconia-containing alkali resistant glass fiber has a large reinforcing effect and is inexpensive,
It is widely used for interior and exterior materials of buildings and exterior products.

However, even though the fiber-reinforced cement has high strength, its Young's modulus is equal to that of ordinary concrete, so that
As the thickness is reduced, the rigidity becomes insufficient and the deflection against external force increases. As a method of preventing this bending, reinforcing ribs are provided on the four circumferences of the plate, or reinforcement is performed from the backside with a steel frame. When it is used as an outer wall material of a normal building, the wind pressure may be mainly considered, and the size thereof is about 1 tonf / m ² at most in any high-rise building. When this is used as a concrete formwork, the external force to be considered is concrete lateral pressure, which is at least ² tonf / m ² , and when it is large, 10 tonf / m ² .
It will be ² . To withstand such a large external force,
The height and width of the ribs on the four sides of the fiber-reinforced cement board are 2
Since it is over 100 mm, not only can the weight reduction benefits of fiber reinforcement not be utilized, but under the current circumstances where the thickness of the fiber reinforced cement plate, which is the surface material, is not considered to be the thickness of the concrete structure, the rib height is wasted. Since it is thick, it is disadvantageous in terms of cost performance.

[0008]

The inventors of the present invention can withstand a large concrete lateral pressure and weigh 120 kg per 1 m ^2.
In order to realize the following lightweight driving form panel, as a result of diligent study, as a result, a relatively thin-walled fiber reinforced cement board having a thickness of 15 mm or more and 50 mm or less and a truss having a relatively high trussing of 100 mm or more and 350 mm or less It has been found that it can be achieved at extremely low cost by combining it with truss-shaped reinforcing bars.

That is, the lightweight casting form panel of the present invention is used as a concrete placing formwork, and in the placing form panel forming the surface after concrete placement, the truss consisting of upper chord member, lower chord member and diagonal member. The lower chord member of the bar-shaped reinforcing bar is embedded in the fiber-reinforced cement plate with a thickness of 15 mm or more and 50 mm or less, and the truss of the truss-shaped reinforcing bar is 100 mm or more and 350 mm or less, and the total weight of the panel is 12 per 1 m ^2.
It is characterized by being 0 kg or less.

The difference between the present invention and the existing Omnia board or Kaiser board is that the thickness of concrete of the Omnia board or Kaiser board is as thick as 60 to 80 mm, whereas the thickness of the fiber reinforced cement board of the present invention is as follows. It is as thin as 15 to 50 mm, and the truss due to the truss-shaped reinforcing bar of the omnier plate or Kaiser plate is usually around 75 mm, whereas in the present invention it is relatively high at 100 to 350 mm. That is, the driving form panel of the present invention,
It has a structure in which the rigidity of the panel depends more on the truss bar than the existing Omnia plate or Kaiser plate, and as a result, in the panel of the present invention, an unexpected accident occurs at the plate end where the truss-shaped reinforcing bar does not work effectively. There is a risk of Therefore, in order to make the present invention more effective, it is preferable to provide a concave groove and a convex projection in the forefront of the fiber reinforced cement plate and connect the adjacent panels by fitting. In this case, it is more effective if the adjacent panels are firmly bound together by using an adhesive or a sheet material.
Also, at least 60m from the edge of the fiber reinforced cement board
m Considering the arrangement of the truss-shaped reinforcing bars so that the reinforcing bars are preferably incorporated within a position of 50 mm, in particular, the position of the truss-shaped reinforcing bars closest to the plate end is arranged closer to the end,
It is also preferable to embed the auxiliary reinforcing bar in the plate end in order to make the present invention effective. Further, in the present invention, it is also effective to make the thickness of the plate end portion 10 to 35 mm thicker than that of the general portion for the purpose of reinforcing the plate end portion.

Fibers for reinforcing the fiber-reinforced cement board used in the present invention include glass fiber, organic fiber, carbon fiber,
Although it can be arbitrarily selected from metal fibers and the like, zirconia-containing alkali-resistant glass fibers are most suitable because they are inexpensive, have high reinforcing efficiency, and are easy to handle.

The thickness of the fiber reinforced cement board in the present invention is 15 mm or more and 50 mm or less. 15mm thick
If it is thinner, the covering thickness of the truss lower chord material to be buried becomes smaller, and the necessary pulling-out proof strength cannot be obtained.
When it is thicker than mm, the panel weight becomes heavier than 120 kg per 1 m ² , and the merit of weight reduction which is the object of the present invention is lost.

In the present invention, the total weight of the panel is 1 m.
120kg or less per ² but 100k per 1m ²
It is more preferably g or less. From the same viewpoint, it is effective in the present invention to set the thickness of the fiber reinforced cement plate to 15 mm or more and 45 mm or less.

The truss due to the truss-shaped reinforcing bar used in the present invention is 100 mm or more and 350 mm or less. If the truss is less than 100 mm, the thin plate panel as in the present invention has insufficient rigidity, and the flexure at the time of placing concrete becomes large, and the plate portion is destroyed. Further, in order to suppress the deflection, the truss is preferably 125 mm or more. If the truss is higher than 350 mm, there is a risk of buckling and it is not realistic in relation to the thickness of the cast concrete. From the relationship with the thickness of the cast concrete, it is more realistic for the truss to have a thickness of 300 mm or less.

[0015]

【Example】

[Example 1] Four types of test bodies as shown in Figs. 1 to 4 and Table 1 were prepared, and a bending test was carried out by a 4-equivalent point loading method with a span of 2 m. Concrete has a nominal strength of 210 kg / c
m ² and GRC contain 2.5% by weight of zirconia-containing alkali resistant glass fiber having a fiber length of 19 mm. The truss-shaped rebar used for concrete is a Kaiser bar with a diameter of the upper chord of 13 mm, a lower chord and a diagonal of 6 mm, and a truss of 75 mm. The truss-shaped rebar used for GRC is the upper chord of 13 mm and the lower chord. And Kaiser muscle with a diagonal diameter of 6 mm and a truss 200 m. In the bending test, only the GRC plate portion was loaded on the panel having the Kaiser streak.

[0016]

[Table 1]

As can be seen from Table 1, the combination of thin-walled GRC and Kaiser muscle results in a surprising increase in bending stiffness and strength. That is, the product of the present invention (test sample No. 4), which is a combination of a relatively thin fiber-reinforced cement plate and a truss-shaped reinforcing bar having a relatively high truss, is a comparative product (test sample No.
It was found to have higher strength than those of 1 to 3).

[Example 2] GR containing 2.5% by weight of zirconia-containing alkali-resistant glass fiber having a fiber length of 19 mm
By changing the thickness of the C plate, a panel was manufactured in which one truss-shaped reinforcing bar having a diameter of the upper chord member of 13 mm, a lower chord member and a diagonal member of 6 mm, and a truss 200 mm was embedded at a ratio of 250 mm in width. The Kaiser muscle lower chord material was embedded in the center of the GRC plate in the thickness direction. Table 2 shows the cover thickness, pull-out strength and total panel weight of the trusses of these test bodies.

[0019]

[Table 2]

When placing 1 m of concrete, about 2.
Since a lateral pressure of 3 tonf / m ² is applied, a GRC thickness of 10 mm cannot withstand, but a GRC thickness of 15 mm can withstand. Moreover, when the thickness of GRC is 60 mm, the total weight of the panel is as heavy as 131 kg / m ² , but it is 50 mm.
The weight is 115 kg / m ² and can be considerably reduced. GRC
If the thickness of the panel is 45 mm, the total panel weight is 100 kg.
/ M ² or less.

[Example 3] A zirconia-containing alkali-resistant glass fiber having a fiber length of 19 mm was contained in an amount of 2.5% by weight, and 1
Truss-shaped reinforcing bars having a diameter of 13 mm for the upper chord member and a diameter of 6 mm for the lower chord member and the diagonal member and having different trusses were embedded in a GRC plate of 700 × 500 × 30 mm at a position with a cover thickness of 17 mm from the rear surface of the GRC of the lower chord member. A bending test was performed on the nine types of panels with a span of 1.5 m by a quadrant loading method. In this case, a load was not applied to the truss-shaped reinforcing bar, and a jig in which the load was applied only to the GRC plate portion was prepared, a bending test was performed, and the results are shown in Table 3.

[0022]

[Table 3]

When pouring concrete for 1.5 m, the lateral pressure is about 3.5 tonf / m ² . Therefore, the 90 mm truss cannot withstand the concrete lateral pressure. The truss can withstand 100 mm, but the deflection is 1/50
It exceeds 0. If the truss is 125 mm or more, the deflection is 1/500 or less, and concrete can be placed with confidence.
If the truss is 400 mm, the truss-shaped reinforcing bar will be deformed even if the load can withstand the load. Truss 350mm
Since the panel strength was larger than the pull-out strength of the truss-shaped reinforcing bar, pull-out failure of the truss-shaped reinforcing bar occurred, but it was found that a load of 25 tonf or more can be endured if measures for increasing the pull-out strength are taken.

[Embodiment 4] As shown in FIGS. 5 to 10, zirconia-containing alkali-resistant glass fiber having a fiber length of 19 mm was used as 2.
2000 × 500 × 30 mm GRC containing 5% by weight
A panel in which an upper chord member having a diameter of 13 mm, a lower chord member and a diagonal member having a diameter of 6 mm, and a truss-shaped reinforcing bar 11 having a lower chord member of 200 mm are embedded in the plate 10 at a position 10 mm from the surface of the GRC plate 10 is manufactured as a prototype. As shown in Nos. 11 and 12, the formwork was arranged vertically to conduct a concrete placing test.

An all-in anchor was driven into one concrete wall and the end screw was cut into it, and the length was 300 mm.
Inserted the rebar rod of, and welded it to the top and bottom of the contact points of the upper and lower chord members of the panel, and set up the panel. If the panel has a mating structure, it was fitted and stood up. Concrete having a slump of 18 cm and a nominal strength of 210 tonf / m ² was poured therein little by little, and the panel was observed at 1 m, 1.5 m and 2 m. The results are shown in Table 4.

[0026]

[Table 4]

Although Table 4 is all within the scope of the present invention, as can be seen from Table 4, since the panel of the present invention uses the thin-walled fiber-reinforced cement plate, the truss-shaped reinforcing bar does not work effectively at the plate end portion. There is a weak point. As a method of covering this weak point, 60 mm, preferably 50 mm, from the end of the fiber reinforced cement board, which is connected by fitting with an adjacent panel.
Position the truss-shaped rebar near the end so that the rebar is built in at the position, or embed the auxiliary rebar in the plate end, or thicken the plate end to provide ribs to increase the plate end. It is preferably reinforced in some way.

[0028]

INDUSTRIAL APPLICABILITY The present invention is effective for protection of forest resources and labor saving of on-site placement work of concrete, and a high-strength, lightweight driving form which solves the problem that the existing Omnia plate and Kaiser plate are heavy. It is a panel. This can be achieved by combining a relatively thin-walled fiber-reinforced cement plate having a thickness of 15 mm or more and 50 mm or less and a truss-like reinforcing bar having a truss with a relatively high truss size of 100 mm or more and 350 mm or less. The present invention becomes even more effective by reinforcing the plate edges that do not work effectively.

[Brief description of drawings]

1 is a No. 1 table. 1 shows a test body of 1,
(A) is the top view and (b) is the sectional view.

FIG. 2 No. of Table 1 2 shows a test body of 2,
(A) is the top view and (b) is the sectional view.

FIG. 3 No. of Table 1 3 shows the test body of 3,
(A) is the top view and (b) is the sectional view.

FIG. 4 No. 1 in Table 1 4 shows a test specimen of 4,
(A) is the top view and (b) is the sectional view.

5 is a table of No. 4 in Table 4. It is sectional drawing which shows the test body of 22.

6 is a table of No. 4 in Table 4. It is sectional drawing which shows the test body of 23.

7 is a table No. 4 shown in FIG. It is sectional drawing which shows 24 test bodies.

FIG. 8 No. It is sectional drawing which shows the 25 test body.

9 is a table of No. 4 in Table 4. It is sectional drawing which shows the test body of 26.

10 is a table of No. 4 in Table 4. It is sectional drawing which shows the 27 test body.

FIG. 11 is a formwork in which the test bodies of Table 4 are vertically arranged.

12 is a cross-sectional view of the mold of FIG.

[Explanation of symbols]

 10 GRC plate 11 Truss-shaped rebar

Claims (1)

[Claims] 1. In a driving form panel which is used as a concrete pouring formwork and forms a surface after concrete pouring, a lower chord member of a truss-shaped reinforcing bar composed of an upper chord member, a lower chord member and a diagonal member has a thickness of 15 mm. Above all, it is embedded in the fiber reinforced cement board of 50 mm or less,
A lightweight driving formwork panel, characterized in that the total panel weight is 120 mm or less per 1 m ^{2 in a} range from mm to 350 mm.