JPH0657957B2 - Reverse floor construction method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a reverse floor construction method for constructing a basement floor having a floor height larger than that of a normal basement floor. Used for.

[Conventional technology]

When the basement floor is constructed by the upside down construction method, since the constructed floor structure of the upper floor serves as the support work for the mountain retaining wall, it is usual not to provide the support work such as the cut beams.

However, even in the upside down construction method, if the floor height of the basement floor is larger than the normal floor height (3.5 m to 4.5 m), it may not be possible to deal with this by increasing the strength (bending rigidity, etc.) of the retaining wall. Since the construction cost of the retaining wall is huge and it is uneconomical, a retaining beam may be installed to support the retaining wall by installing a girder near the basement floor.

Conventionally, H-shaped steel has been used as the cross beam.

Further, although it is a conventional technique that is intended not for the timber but for the abdomen, the support structure of RC construction is known from Japanese Patent Publication No. 61-35331. This is because a steel suspension formwork is suspended and supported by an upper support (abdomen up) provided along the mountain stop wall, and the reinforcement form and concrete are placed in the suspension formwork, By constructing the RC construction support of, after that, the hanging form is diverted downward and the same process is repeated,
The RC construction will be built in order from top to bottom.

[Problems to be solved by the invention]

The former conventional example has the following problems.
That is, it is very difficult to carry in and carry out long steel frames for beams because of the reverse construction method, and since the floor height is large, the formwork for floor structures, the reinforcing bars and other quality materials are carried in. However, diversion is difficult, and there is a problem that work efficiency is lowered and construction cost is increased due to the necessity of ensuring safety.

Many of the above problems can be solved by applying the latter conventional technique to a girder to form a RC girder. That is, in the case where the cutting beam is RC construction, after the construction of the floor structure of the basement floor, the cutting beam can be crushed and handled as concrete glass, so that it can be easily carried out of the site, and within a range that does not hinder excavation work. Since the beam width of the RC beam can be set arbitrarily, it is possible to widen the RC beam to be used as a working floor in the middle part of the floor height.

However, in the case of an RC-made working floor that also serves as a girder, when axial force (horizontal force) due to earth pressure is applied, there is a risk that the central portion of the working floor that serves both as a girder will bend upwards, and therefore crushing is a prerequisite. Despite being a temporary material, it was necessary to have a cross-sectional shape with a beam similar to that of the floor structure of the main installation or to have a significantly thicker thickness. Therefore, the amount of concrete and rebar used is large, the work of removing the dismantled and removed pieces is troublesome, and a hanging formwork for a working floor that also serves as a girder is required.

The object of the present invention is to construct a basement floor with a large floor height by the upside down construction method, and the above-mentioned problems that occur when the cutting beam installed near the middle of the floor height is an RC construction working beam To solve the problem.

[Means for solving problems]

The technical means taken by the present invention to achieve the above object are as follows. That is, the underground floor reverse construction method according to the present invention constructs the floor structure of the upper floor and digs the ground on the inner side of the retaining wall to a predetermined depth, and then places earth concrete on the excavated bottom. An RC-built working floor that also serves as a girder is hung, and the working floor that also serves as a girder is hung and supported by the floor structure of the upper floor, and is temporarily installed between the working floor that also serves as the girder and the floor structure of the upper floor. It is characterized by constructing a floor structure on the lower floor by excavating the ground below the working floor that also serves as a girder to a predetermined depth while interposing columns.

[Action]

According to the above-mentioned structure, since the concrete floor is placed on the excavated bottom to construct the RC beam work floor that also serves as a girder, there is no need for a bottom formwork for the work platform that serves both as a girder and support work for the bottom formwork. Is.

The RC working floor also serving as a girder serves as a girder that supports the mountain retaining wall, and is also used as a work passage, a floor structure formwork, and a material storage space for reinforcing bars and the like.

In the state in which an RC-structured working floor also serving as a girder is suspended from and supported by a floor structure of an upper floor, and a temporary support column is interposed between the working floor serving also as a girder and the floor structure of the upper floor, Since the ground below the combined working floor is excavated, it works on the mountain retaining wall without making the working floor also used for beams and girders extremely thick or for increasing the bending rigidity by building beams on the lower surface of the working floor for both beams and girders. There is no risk that the central portion of the working floor that also serves as a girder will bend in either the upper or lower direction due to the earth pressure.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

In the figure, 1 is a retaining wall made up of columns or continuous walls, and 2 is an RC-structured working floor for beams and girders. It is suspended and supported by a plurality of suspension rods 4 made of (steel rods having threaded portions only at both ends) or the like, and between the working beam 2 also serving as a girder and the floor structure 3. Intervenes a temporary support column 5 such as a pipe support in the vicinity of the position of suspension by the suspension rod 4 to deform the working floor 2 that also serves as a beam in two directions, that is, the suspension rod 4 deforms downward. The temporary columns 5 are configured to prevent upward deformation. 6a and 6b are washers. At the upper and lower ends of the hanging rod 4,
A nut member 7 such as a hexagonal nut or a hexagonal long nut (a coupler for a thread-bar rebar) is screwed on. Reference numeral 8 indicates an RC angry belly, and reference numeral 9 indicates a basement pillar. 10 is a beam.

The reverse construction method for the basement floor will be described in the order of steps as follows.

First, as shown in FIG. 3 (a), the ground inside the retaining wall 1 is excavated to some extent to construct the floor structure 3 on the ground floor, and then the ground is dug to a predetermined depth. In the state where the opening necessary for the subsequent excavation work is left on the excavation bottom 11, the side formwork 12 for double-cutting and working floor molding and the formwork for belly-up formation
13 is installed, and the upper end of the hanging rod 4 is supported by the nut member 7 on the floor structure 3, and a washer 6a is attached to the lower end of the hanging rod 4.
The nut member 7 is screwed on via.

In this state, the concrete frames 12 and 13 are laid out and concrete is poured into the soil to build a working floor 2 also serving as a cross beam and an abdomen 8 as shown in FIG. Here, the earth concrete means concrete that is directly placed on the excavated bottom 11 without laying a bottom formwork, but also includes the case where concrete is placed by laying a waterproof sheet such as vinyl. There is.

After the required strength is developed in the working beam 2 for both beams and the abdomen 8, the temporary construction is performed between the working floor 2 for both beams and the floor structure 3 as indicated by the broken line in FIG. 3C. The pillar 5 is interposed to prevent the work floor 2 which also serves as a girder from being deformed upward. That is, the working beam 2 that also serves as a girder is prevented from being deformed downward by the suspension rod 4 and is prevented from being deformed upward by the temporary support column 5. In this state, the work floor 2 which also serves as a beam is excavated to a predetermined depth.

Thereafter, as shown in FIG. 3D, the floor structure 3 on the first basement floor is constructed. The suspension rod 4 is inserted into the floor structure 3 prior to the concrete pouring, and the nut member 7 is screwed to the lower end portion of the suspension rod 4 via the washer 6a. Next, on the excavated bottom 11, the side formwork 12 for forming the working beam and the workbed and the formwork 13 for forming the bellows are installed, and the reinforcement and the soil concrete are placed, and as shown in FIG. As shown, the working floor 2 which also serves as a girder and the abdomen 8 of the second stage are built. After the required strength is developed in these, as shown by the broken line in the figure, the temporary support pillar 5 is interposed between the second-level working floor 2 also serving as a girder and the floor structure 3 on the first basement floor, and the temporary support pillar is provided. In a state in which the vertical beam 5 and the suspension rod 4 are prevented from being deformed in the vertical direction, the working floor 2 also serving as a beam is excavated to a predetermined depth, and as shown in FIG.
The floor structure 3 on the second basement floor is formed, and thereafter, the same steps are repeated.

The hanging rod 4 of the working floor 2 for both beams and girders and the hanging rod 4 of the working floor 2 for both beams and girders may be separated from each other, as shown in FIG. (2) are connected to each other until a suitable time by using a connecting rod 4'having a predetermined length, and the upper working beam 2 for both beams and working beams for lower beams 2
It may be used together with the suspension support of. Further, in the illustrated embodiment, the working floor 2 for both beams and the first floor, the floor structure 3 for the first basement floor, the working floor 2 for both the beams and second floor, and the floor structure 3 for the second basement floor
Construction work was done in this order, but the working floor for both beams and beams for the first and second steps
After the construction, a floor structure 3 on the first basement floor is constructed in the middle between the first-level working beam and double-purpose working beam 2 and the third-level working beam is also used. After constructing the work floor 2, the floor structure 3 on the second basement floor may be constructed at an intermediate portion between the second-tier beam-combined work floor 2 and the third-stage beam-combined work floor 2. .

In the figure, 14 is concrete on the outer wall of the basement floor. The working floor 2 that also serves as a girder and the abdomen 8 may be removed and removed each time they are no longer needed, or after the construction has been completed up to the lowest floor, the ones at the lowest stage may be disassembled and removed. Further, in the illustrated embodiment, the abdomen 8 is also made of RC, but steel may be used for the abdomen 8.

〔The invention's effect〕

Since the present invention has the above-mentioned configuration, the following effects can be obtained.

The RC floor work floor that also serves as a girder serves as a girder that supports the mountain retaining wall, and is also used as a work passage, a formwork for floor structures, and a material storage space for reinforcing bars, etc. Even if the size is large, you can work easily and safely.

Since an earth concrete is cast on the excavated bottom to construct a working floor that is also used as an RC girder, there is no need for a bottom formwork for the working floor that serves both as a girder and support work for the bottom formwork.

In particular, in the state where an RC-structured working floor also serving as a girder is suspended from and supported by a floor structure on the upper floor, and a temporary strut is interposed between the working floor serving also as a girder and the floor structure on the upper floor, Since the ground below the working floor that also serves as a beam is excavated, a mountain stopper is not required even if the working floor that also serves as a beam is made extremely thick, or if the beam is built on the lower surface of the working floor that serves as a beam to increase bending rigidity. There is no fear that the central portion of the working floor that also serves as a girder will bend in either the upper or lower direction due to the earth pressure acting on the wall.

Therefore, the amount of concrete and rebar used is small,
It is easy to perform the lifting work at the time of dismantling and removal, and it is very economical in combination with the fact that there is no need for the bottom formwork of the working floor that also serves as a girder and the support work for the bottom formwork.

[Brief description of drawings]

The drawings exemplify an embodiment of the method for constructing an upside down basement according to the present invention. Fig. 1 is a sectional view of a main part, Fig. 2 is an overall schematic plan view, and Figs. 3 (a) and 3 (b). , (C), (D),
(E) and (f) are process explanatory drawings. DESCRIPTION OF SYMBOLS 1 ... Mountain stop wall, 2 ... Work floor that also serves as beams, 3 ... Floor structure, 4
… Suspension bars, 5… Temporary columns.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Mukai 4-27, Honmachi, Higashi-ku, Osaka City, Osaka Prefecture Takenaka Corporation, Osaka Main Store (72) Inventor Narumi Tashiro 4-27, Honmachi, Higashi-ku, Osaka Takenaka Corporation Osaka Main Store

Claims (1)

[Claims] 1. After constructing a floor structure of the upper floor and digging the ground inside the cliff wall to a predetermined depth, placing earth concrete on the bottom of the excavation to construct a working floor for RC beams and beams. In the state of being built, the working floor also serving as a girder is hung and supported by the floor structure of the upper floor, and the temporary strut is interposed between the working floor serving as a girder and the floor structure of the upper floor. A method for reverse construction of a basement floor, which comprises constructing a floor structure of a lower floor by excavating the ground below a working floor that also serves as a girder to a predetermined depth.