JPS59145855A - Floor construction using precast panel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a floor construction method using precast boards in which a composite floor is formed by integrating a precast board hung between beams and cast-in-place concrete poured on the top surface of the precast board.

Conventionally, in the floor construction method using precast boards made of PC concrete, cast-in-place concrete is placed on the upper surface of the precast board passed between the beams.

It is also known that the stress level of concrete structures is generally proportional to the square of the thickness. Therefore, when cast-in-place concrete is placed on the top surface of a precast board, if the two are completely integrated, the thickness of the two overlapped can be regarded as one structure thickness for stress calculation, but the bond between the two If the stress is insufficient, the overall stress must be calculated using only the stress of the precast board.

Therefore, if cast-in-place concrete is simply placed on the top surface of a smooth precast board, the bond between the two will not be sufficient;
As a result, the thickness of the precast plate must be increased in order to obtain the necessary stress level.

Focusing on this point, we created a precast plate with two sides of a bamboo bar with an approximately triangular cross section as a method to integrate the precast plate and cast-in-place concrete, and to consider the overall thickness as an integrated structure when calculating the stress level. A synthetic floor construction method has been developed in which the remaining side of the precast board is exposed on the surface of the precast board, and this is embedded in cast-in-place concrete to integrate the two.

However, in this conventional method, a portion of the dragon stripes protrude from the surface of the precast board, making it impossible to continuously form the precast board, resulting in high manufacturing costs (in addition, the dragon strips protrude during storage, transportation, and installation). Since the simple reinforcements in the mold are easily deformed, they must be handled carefully, and there are also problems with workability.

In view of the above-mentioned conventional problems, the present invention uses a precast board that is easy to form and is inexpensive, and can be easily implemented without adding any special members or processes when constructing a floor. The purpose of this project is to provide a floor construction method using precast boards that reliably integrates concrete and cast-in-place concrete, and that provides the necessary stress level with the same thickness as a floor that is integrally formed. This is a floor construction method using precast boards, in which precast concrete boards are hung between steel frames or concrete beams, and cast-in-place concrete is poured on top of the boards. The cast-in-place concrete is integrally poured into the recessed part, thereby acting as a shako starter and integrating the precast board and the cast-in-place concrete, resulting in a mechanically synthesized floor. This method consists of a floor construction method using precast boards.

Next, embodiments of the present invention will be described with reference to the drawings.

First, a concrete precast board used in the present invention will be explained based on FIGS. 1 to 4.

Fig. 1 is a partial perspective view of an example of a precast board used in the present invention, and this precast board A has a plurality of hollow holes 1°1... passing through it in the longitudinal direction within its wall thickness. It is open, and a large number of PC1 wires 2, 2, . . . are buried under tension in the upper and lower positions.

On the other hand, a large number of shallow recesses 3, 3, . . . are formed on the upper surface. These concave portions 3, 3. - As an example, the second
As shown in the figure, it is formed into a tapered shape with a smaller diameter at the bottom, and its size is as follows: opening diameter a is 25 ml, bottom diameter is 17 m ra, depth h is 5n+i, and the angle α of the tapered surface is 45°. There is.

In addition to the circular shape mentioned above, the shape of this recessed part 3 is triangular,
It may be a square or other polygonal shape, and its size may also be changed.

In addition to the above-mentioned precast boards used in the present invention, the precast boards used in the present invention include
As shown in the figure, the precast plate may have a solid shape with no hollow holes, the PC steel wire 2 may be buried under tension in the longitudinal direction, and a number of recesses 3 may be formed on the surface. .

For example, the production of each of the precast plates A and A' involves immediately demolding by tensioning the PC steel wire 2 on a flat mold such as a floor surface, and moving the formwork while pouring concrete to embed it. After molding using the method and finishing the surface flat,
A concave molding die having a large number of protrusions 5, 5, . . . protruding from the outer periphery of a circular drum 4 as shown in FIG.

After the surface is molded in this manner, it is allowed to stand and harden to reach a strength greater than or equal to that of a steel, and is then cut into a required length to form a precast board of unit length.

Next, the process of constructing a composite floor using the precast board A formed as described above will be explained.

First, the precast boards A are hung horizontally at regular intervals between the beams. At this time, if the beam is a concrete beam on the end side of the precast plate A, anchor reinforcing bars 11 are made to protrude from the upper surface of the beam 1o, as shown in FIG.

Place the end of A. Also, if the beam is a steel frame, the 6th
As shown in the figure, a stud 13 is provided protruding from the center of the beam 12, and precast plates A are placed on both sides of the stud 13.

Place the end of A.

After passing a large number of precast plates A, A, etc. in this way, reinforcing bars 15 for cast-in-place concrete are installed on the top surface, and cast-in-place concrete 1-8 is placed between precast plates A and A. and pour it over the entire upper surface to form a composite floor.

In the composite floor constructed in this way, the cast-in-place concrete B has a concave area of 3°3 on the surface of the precast board.
By entering and hardening, the concave portions 3, 3...
The concrete inside acts as a bulge starter, and the precast board A and cast-in-place concrete B are integrated, and act as one against bending due to vertical loads. Moreover, the precast plates A are integrated with each other via cast-in-place concrete by the action of the above-mentioned shako starter.

LL As shown in Fig. 7, the thickness h is 1001111S on the surface of the PC precast board A whose width Form one surface in a staggered manner with intervals of , and a thickness h2 of 80
A composite floor test piece was produced by pouring cast-in-place concrete B of mm in thickness to a total thickness h of 1801111Il, and a short-term test was conducted on this and the PC precast board A alone, as shown in Table 1. It was like that.

In addition, when we conducted a deflection test on synthetic floor test piece No. 011 in Table 1, the results were as shown in the graph in Figure 8. As shown in the graph in Figure 10, the experimental values for both cracking load and maximum yield strength exceed the calculated values for the whole unit. Unity was confirmed.

Furthermore, the fracture behavior was normal bending or shear fracture, and the fracture phenomenon of the joint surface was not observed until the end, and the integrity was confirmed from the fracture behavior.

C) Regarding the load-deformation curve, all experimental values show that the elastic stiffness exceeds the calculated value. Also, when looking at the film layer characteristics of the curve, no reduction that would cause loss of integrity of the joint surface was observed.

These confirmed the integrity of the floorboards.

(3) Regarding the crack properties, the crack passes through the splicing surface in almost a straight line, and no progress is observed along the splicing surface. Therefore, the integrity of the floorboard was confirmed from the viewpoint of crack properties.

(a) Regarding the slippage of the joint surface, the slippage of the joint surface was 0 to 0.01111 m or less, and it was confirmed that the integrity was maintained.

■ Regarding flatness retention, when looking at the results of plotting the skewness in the thickness direction, it is recognized that the cross section maintains almost a flatness.

Therefore, the integrity of the spuncrete composite floorboard was confirmed.

As mentioned above, strength, rigidity, fracture property, cracking property,
The structural integrity of the composite floorboard was confirmed from both the slippage of the joint surface and the ability to maintain the flatness of the cross section.

The present invention is constructed as described above, and a large number of recesses are provided on the surface of a precast board, and cast-in-place concrete is poured on the upper surface of the precast board, so that the cast-in-place concrete that fits into the recesses serves as a stopper. As a result of this, a strong integration was achieved as shown in the experimental example, and during construction, the strength could be calculated by considering the total thickness of the precast board and cast-in-place concrete as the thickness of the integrated structure. This method is extremely advantageous compared to conventional construction methods in terms of cost and workability.

[Brief explanation of drawings]

Fig. 1 is a partial perspective view of an example of a precast board, Fig. 2 is an enlarged sectional view of a recessed part, Fig. 3 is a partial perspective view of another example of a precast board, and Fig. 4 is a sectional view of a mold for forming a recessed part. , Fig. 5 is a partial cross-sectional view of an example of the installed state of flexible steel 1 to the end of the board, Fig. 6 is a cross-sectional view of an example of the bundled product, Fig. 7 is a cross-sectional view of a synthetic floor test piece, and Fig. 8 is a deflection The graphs showing the test results are as follows: Fig. 9 is a graph showing the amount of slippage of the joint surface, and Fig. 10 is a graph not showing the flatness of the cross section. AI...Flexible 1r strike plate B...Cast-in-place concrete')...Hollow hole 2...PC steel wire 3...
-・Concave portion 10.12...Beam.

Claims (1)

[Claims] (1) In a floor construction method using precast boards, in which precast concrete boards are hung between steel beams or concrete beams, and cast-in-place concrete is poured on top of the boards, the precast boards have many recesses on their surfaces. The cast-in-place concrete is integrally poured into the recessed part to serve as a shako starter, and the precast plate and the cast-in-place concrete are integrated, and the cast-in-place concrete is mechanically synthesized. A floor construction method using precast boards that is characterized by being used as a floor.