JP4995696B2 - Construction method of structure - Google Patents

Description

  The present invention relates to a structure construction method. Specifically, the present invention relates to a method for constructing a structure having a precast concrete column and a precast concrete beam in which prestress is introduced over a plurality of spans.

  Conventionally, columns and beams of structures are manufactured in advance as precast concrete columns (hereinafter referred to as PCa columns) and precast concrete beams (hereinafter referred to as PCa beams) at a factory, and these PCa columns and PCa beams are manufactured. A precast concrete structure is known in which construction is carried out by transporting the material to the site.

  Further, the precast concrete structure includes a precast / prestressed concrete structure in which prestress is introduced into the PCa beam over a plurality of continuous spans.

  In the above precast / prestressed concrete structure, after the construction work of the PCa column and the PCa beam, grout is filled in the joint of the column base of the PCa column, and the column base of the PCa column is placed on the lower floor. Fix it. Thereafter, a PC steel wire is inserted into the PCa beam, the steel wire is tensioned, and prestress is introduced.

  However, when prestress is introduced into the PCa beams, these PCa beams contract in the axial direction. Then, even though the column base portion of the PCa column is already fixed, the column head is pulled toward the center of the structure, and there is a big problem especially for the PCa column located on the outer peripheral side of the building. In some cases, static stress was generated.

In order to solve the above problems, the following two methods have been proposed.
That is, there has been proposed a method in which post-cast concrete is placed in the central portion of the PCa beam without introducing prestress into the PCa beam (see Patent Document 1).
According to this method, since prestress is not introduced into the PCa beam in the continuous multi-span direction, the statically indefinite stress can be reduced.

In addition, prestress is introduced into a continuous multi-span PCa beam, but instead of introducing prestress into the PCa beam at once, the prestress introduction range is divided into a plurality of parts and prestress is introduced every predetermined span. A technique to do this has been proposed (see Patent Document 2).
According to this method, the statically indefinite stress can be reduced as compared with the case where prestress is introduced at a time.
JP 2006-176986 A Japanese Patent No. 2703265

However, the technique disclosed in Patent Document 1 can reduce the static instability generated in a continuous multi-span PCa beam, but does not introduce pre-stress, and therefore cannot fundamentally solve the problem of static instable stress.
Moreover, in the method shown in Patent Document 2, the prestress introduction range is divided into a plurality of parts and the prestress is introduced for each predetermined span. In addition to the increase in the number of wires, the number of fixing devices also increased, which could increase the cost. In addition, since the number of man-hours increases, there is a possibility that the construction period becomes longer.

  An object of this invention is to provide the construction method of the structure which can reduce the statically indefinite stress which generate | occur | produces at the time of introducing low prestress to many continuous spans at low cost and a short construction period.

  (1) A plurality of precast concrete columns (for example, a PCa column 11 described later) and a plurality of precast concrete beams (for example, a PCa beam 12 described later) bridged over the plurality of precast concrete columns, A method for constructing a structure in which prestress is introduced into a precast concrete beam over a span, wherein a construction step for constructing the plurality of precast concrete columns and a plurality of precast concrete beams, A pre-stress introduction step for introducing pre-stress over a plurality of spans at a time, and a column fixing step for fixing the pre-cast concrete column to a floor immediately below the column (for example, a frame 13 on the floor immediately below). A method for constructing a structure characterized by being performed.

According to the present invention, first, a plurality of precast concrete columns and a plurality of precast concrete beams are constructed, and then a prestress is applied to a plurality of spans at a time by tensioning the tension members of the precast concrete beams. Introduce. After that, these precast concrete columns are fixed on the floor directly below the columns. Here, when prestress is introduced into the precast concrete beams, the precast concrete columns slide horizontally, so that it is possible to prevent indefinite stress from occurring in these precast concrete columns.
In addition, since prestress can be introduced at once over multiple continuous spans, the construction period can be shortened and the number of tension materials (PC steel wires) and fixing tools used for prestress introduction can be reduced, thereby reducing costs. .

  (2) In the construction method of the structure according to claim 1, before the prestress introduction step, at least one of the precast concrete columns over the plurality of spans is selected, and the selected precast concrete column ( For example, a selection column fixing step of fixing a below-mentioned fixed column 11A) to the floor immediately below the column is performed, and in the column fixing step, the remaining of the precast concrete columns over the plurality of spans (for example, a below-described slide column 11B) ˜11D) is fixed to the floor immediately below the pillar.

According to the present invention, one of the precast concrete columns over a plurality of spans is selected, and the selected precast concrete column is fixed to the immediately lower floor. Next, prestress is introduced into the precast concrete beam over multiple spans at once. Then, the remainder of the precast concrete pillars over a plurality of spans is fixed to the floor immediately below.
Therefore, when prestress is introduced, the above-mentioned selected column becomes a fixed point, and the remaining column slides toward the selected column. By appropriately selecting the selected column, the remaining column slide amount can be reduced.

  According to the present invention, first, a plurality of precast concrete columns and a plurality of precast concrete beams are constructed, and then a prestress is applied over a plurality of spans at a time by tensioning the tension members of the precast concrete beams. Introduce. After that, these precast concrete columns are fixed on the floor directly below the columns. Here, when prestress is introduced into the precast concrete beams, the precast concrete columns slide horizontally, so that it is possible to prevent indefinite stress from occurring in these precast concrete columns. In addition, since prestress can be introduced at once over multiple continuous spans, the construction period can be shortened and the number of tension materials (PC steel wires) and fixing tools used for prestress introduction can be reduced, thereby reducing costs. .

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of a structure 1 to which a structure construction method according to an embodiment of the present invention is applied.
The structure 1 includes PCa columns 11 as seven precast concrete columns, and PCa beams 12 as six precast concrete beams spanned over the seven PCa columns 11.
The seven PCa pillars 11 are located at the pillar positions X1 to X7.

  Each PCa beam 12 and each PCa column 11 incorporate a cylindrical sheath (not shown) extending over six spans. A PC steel wire 122 is inserted through the sheath, and the PC steel wire 122 is tensioned and fixed by a fixing tool 123. The gap between the sheath and the PC steel wire 122 is filled with non-shrink grout.

  The PC steel wire 122 extends linearly along the axial direction of the PCa beam 12 over 6 spans, so that prestress is introduced into the PCa beam 12 along the axial direction. Further, by providing the PC steel wire 122 linearly along the axial direction of the PCa beam in this way, a decrease in prestress due to friction between the PC steel wire 122 and the sheath is prevented.

FIG. 2 is an enlarged cross-sectional view of the column base portion of each PCa column 11.
The column reinforcement 111 at the column base of each PCa column 11 is connected to a column reinforcement 113 protruding from the housing 13 on the floor immediately below the PCa column 11 by a sleeve joint 112. Specifically, the inner diameter of the sleeve joint 112 is larger than the outer diameter of the column bars 111 and 113, and there is a gap between the outer peripheral surface of the column bars 111 and 113 and the inner peripheral surface of the sleeve joint 112. Filled with non-shrink grout.
Here, the housing 13 on the immediately lower floor is, for example, a pillar. The sleeve joint 13 is, for example, a splice sleeve (manufactured by Nippon Splice Sleeve Co.), but may be any cylindrical shape larger than the outer diameter of the column bars 111, 113, and may be, for example, a sheath.

The above structure 1 is constructed in the following procedure.
First, as shown in FIG. 3, the seven PCa pillars 11 are constructed on the frame 13 on the immediately lower floor, and then the six PCa beams 12 are constructed.

  Here, one of the PCa pillars 11 spanning six spans, here, the central PCa pillar 11 is selected. The selected PCa column 11 is a fixed column 11A, and the PCa column 11 positioned outside the fixed column 11A is a slide column 11B. Further, the PCa column 11 positioned outside the slide column 11B is referred to as a slide column 11C, and the PCa column 11 positioned outside the slide column 11C is referred to as a slide column 11D.

The fixed column 11A is disposed at the column position X4.
In addition, positions outside the column positions X3 and X5 by the dimension d1 with respect to the column position X4 where the fixed column 11A is disposed are set as column positions X3A and X5A. The slide column 11B is disposed at these column positions X3A and X5A.

In addition, positions outside the column positions X2 and X6 by the dimension d2 with respect to the column position X4 where the fixed column 11A is disposed are column positions X2A and X6A. This dimension d2 is larger than the dimension d1. The slide column 11C is disposed at these column positions X2A and X6A.
In addition, positions outside the column positions X1 and X7 by the dimension d3 with respect to the column position X4 where the fixed column 11A is disposed are column positions X1A and X7A. This dimension d3 is larger than the dimension d2. The slide column 11D is disposed at these column positions X1A and X7A.

  As shown in FIG. 4, the inner diameter of the sleeve joint 112 and the outer circumference of the column bar 113 are the inner diameters of the sleeve joint 112 even when the slide pillars 11B to 11D are displaced by the dimensions d1 to d3. It is formed larger than the outer diameter of the column bar 113 so as not to interfere with the surface. Thus, by ensuring the large inner diameter of the sleeve joint 112, the slide columns 11B to 11D can slide on the housing 13 on the lower floor.

  Next, non-shrink grout is filled in the sleeve joint 112 of the column base of the fixed column 11A, and the column base of the fixed column 11A is fixed to the housing 13 on the immediately lower floor.

Next, as shown in FIG. 5, the PC steel wire 122 is inserted into a sheath extending linearly over 6 spans, and the joint between the PCa column 11 and the PCa beam 12 is filled with mortar.
After the strength of the joint mortar is developed to a predetermined strength, the fixing tool 123 is installed on one of the slide columns 11D located at both ends of the six spans, and a jack (not shown) is installed on the other. Next, one end of the PC steel wire is fixed to the fixing device 123, and in this state, the PC steel wire 122 is tensioned to the right in FIG. Thereafter, the fixing tool 123 is also attached to the other slide column 11 </ b> D, and the other end side of the PC steel wire 122 is fixed to the fixing tool 123. Thereby, prestress is introduced into the PCa beam 12 over 6 spans.

  Then, as shown in FIG. 6, the fixed column 11A does not slide because the column base is fixed, but the remaining slide columns 11B to 11D slide toward the fixed column 11A. That is, the slide column 11B arranged at the column positions X3A and X5A moves to the column positions X3 and X5, and the slide column 11C arranged at the column positions X2A and X6A moves to the column positions X2 and X6. The slide columns 11D arranged at X1A and X7A move to the column positions X1 and X7.

Then, next, the non-shrink grout is filled in the sheath of the PCa beam 12 and each PCa column 11.
Subsequently, the non-shrink grout is filled in the sleeve joints 112 of the column bases of the slide columns 11B to 11D, thereby fixing the column bases of the slide columns 11B to 11D to the casing 13 on the immediately lower floor.
Next, although not shown, top concrete such as slab is placed.

According to this embodiment, there are the following effects.
(1) First, the seven PCa pillars 11 and the six PCa beams 12 are constructed, and then prestress is introduced into the PCa beam 12 over six spans at a time. Then, these PCa pillars 11 are fixed. Here, when prestress is introduced into the PCa beam 12, the PCa column 11 slides horizontally, so that it is possible to prevent the static stress from being generated in the PCa column 11.
In addition, since prestress can be introduced at once over six consecutive spans, the construction period can be shortened, and the number of PC steel wires and fixing tools used for prestress introduction can be reduced, thereby reducing costs.

(2) One of the PCa pillars 11 extending over 6 spans is selected, and the selected PCa pillar 11 is fixed to the housing 13 on the immediately lower floor as a fixed pillar 11A. Next, prestress is introduced into the PCa beam 12 over 6 spans at a time. Thereafter, the rest of the PCa pillars 11 spanning six spans, that is, the slide pillars 11B to 11D are fixed to the casing 13 on the immediately lower floor.
Therefore, when prestress is introduced, the fixed column 11A becomes a fixed point, and the remaining slide columns 11B to 11D slide toward the fixed column 11A. By appropriately selecting the fixed column 11A, the slide amount of the remaining slide columns 11B to 11D can be reduced.

It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.
For example, in this embodiment, the column base portion of the PCa column 11 is slidably arranged with respect to the housing 13 on the immediately lower floor. It is good.

In the present embodiment, the PC steel wire 122 is linearly arranged. However, the present invention is not limited to this, and the PC steel wire is passed through the upper side of the beam cross section at the end of the beam and the cross section of the beam at the center of the beam. You may pass through the lower side.
Moreover, in this embodiment, although the PC steel wire 122 was tensed in the right direction in FIG. 5, it is not limited to this, and may be tensed in the left direction or in both directions.

It is a side view of the structure to which the construction method of the structure concerning one embodiment of the present invention was applied. It is an expanded sectional view of the column base part of the structure concerning the embodiment. It is a figure which shows the state which performed the construction of the pillar and beam of the structure concerning the said embodiment. It is an expanded sectional view of a column base in the state where construction of a pillar and a beam of a structure concerning the embodiment was completed. It is a figure which shows the state which penetrated the PC steel wire to the pillar and beam of the structure which concern on the said embodiment. It is a figure which shows the state which strained the PC steel wire which concerns on the said embodiment.

Explanation of symbols

11 PCa pillar (precast concrete pillar)
11A fixed column (precast concrete column)
11B-11D Slide column (Precast concrete column)
12 PCa beam (precast concrete beam)
13 Right downstairs

Claims (2)

A method of constructing a structure that includes a plurality of precast concrete columns and a plurality of precast concrete beams spanned by the plurality of precast concrete columns, and in which prestress is introduced into the precast concrete beams over a plurality of spans. And
A construction step for constructing the plurality of precast concrete columns and the plurality of precast concrete beams;
A prestress introduction step of introducing prestress over a plurality of spans at once to the precast concrete beam;
A method for constructing a structure, comprising sequentially performing a column fixing step of fixing the precast concrete column to a floor immediately below the column. In the construction method of the structure according to claim 1,
Prior to the pre-stress introduction step, select at least one of the precast concrete columns across the plurality of spans, and perform a selection column fixing step of fixing the selected precast concrete column to the floor immediately below the column,
In the pillar fixing step, the remaining of the precast concrete columns extending over the plurality of spans is fixed to a floor immediately below the pillar.

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