JPH041363A - Construction method of prestressed concrete structure - Google Patents

Abstract

PURPOSE:To lighten a structure, and to shorten the term of work by forming reaction supporters unified with posts at both end sections of a girder while disposing PC steel in two vertical rows, introducing prestress and placing concrete to residual sections. CONSTITUTION:Reaction supporters 2 as one parts of a girder 1 unified with posts 10 are formed at both end sections of the girder 1 constituting a concrete structure A. PC steel 5 in two vertical rows are arranged between the reaction supporters 2 at both ends while reinforcing bars 4 are installed to connecting sections with each post 10. Prestress is introduced to upper and lower PC steel 5a and 5b, and concrete is placed to residual sections between the reaction supporters 2, thus shaping the girder 1. Accordingly, operating efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing a prestressed concrete structure extending between already formed concrete structures when constructing a concrete structure. be.

``Conventional technology'' As is well known, there are conventional methods for introducing presses and presses when manufacturing prestressed concrete structures, such as the preten-yon method, the boss), and the ten-no-yon method.

The former is PCI! This is a method of applying prestress to the concrete by applying tensile force to the I material and pouring concrete, and after the concrete hardens, the tensile force applied to the PC steel material is transferred to the concrete by the adhesion of the PC steel material and concrete. Also, when using multiple units, P
Embed the source at the position where the CM material will pass, and after the concrete hardens, pass the PCM material through this north and fix one end,
The other end is tensioned by water pressure or oil pressure, and the reaction force applies strong compression to the concrete, which is then fixed using wedges, screws, etc. In this case, in order to protect the steel material and ensure the safety of the members, it is desirable to inject mortar into the lead-through hole to adhere the steel material and the source (pond construction method).

``Problems to be Solved by the Invention'' However, each of the above two methods had the following problems.

In other words, in the britension method, there is no cost for the fixing part, and there is no need for construction such as grout injection.
A sturdy reaction table (ABA, l) for pre-tensioning the PCM material.
In addition, in the Bost Tennoyon method, it is relatively easy to introduce prestressing on site because it does not require very large tension equipment. It required two efforts. Furthermore, the introduction of prestress, that is, the arrangement of the PCM material, must be done in a form that can cancel out the stress generated in the member, and for this purpose, predetermined parts of the PCfl material must be bent to match the form. Therefore, bending and arranging the PCj14 material was a labor-intensive work in both the bulletin board and the boss board.

The present invention has been made in view of the above circumstances, and eliminates the need for a large reaction force table that requires time and effort for transportation and sesotin, eliminates the need for bending the PC1li material, and eliminates the need for sheath placement and grout filling. The purpose of this invention is to provide a method for introducing prestress that eliminates the above operations, that is, a method for introducing prestress that shortens the construction period and reduces costs.

“A means to solve problems.

In constructing a concrete structure, the present invention provides a pre-stressed concrete structure in which a pre-formed concrete structure is provided with two surfaces parallel to tiles and spans between the pre-formed concrete structures.
A process of forming reaction force supports that are integrated with the pre-formed concrete structure at both ends of the prestressed concrete structure to be constructed, and placing a PC steel material between the reaction force supports in the construction oven. a step of arranging the prestressed concrete structures in two rows so as to be located inside the stressed concrete structure and in proximity to the two parallel surfaces and tensioning them; A step of providing reinforcing bars between the two rows of I) CM materials at the joint with the precast concrete structure, and
a step of pouring concrete to form the desired prestressed concrete structure after the material is tensioned;
The method is characterized in that it includes a step of introducing prestress into the concrete 1 by releasing the tension of the PCM material after the cast concrete has hardened.

"Action" Both ends of the prestressed concrete structure to be constructed 1
Cross-linking, such as a rigid frame or multiple rigid frame structure, is utilized to form a counterforce support. In order to tension the PC steel material, it is possible to tension the PCA material on-site without using the large-scale reaction table of the conventional pre-tension method. Furthermore, the prestressed concrete structure to be constructed will have high rigidity because the PCJllji materials will be arranged in two rows (two stages) in the thickness direction. Furthermore, since most of the prestressed conocrete structures formed are prestressed by the so-called punching method, most of the work such as arranging the north and filling with grout can be eliminated.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1 to 4 show the present invention applied to beams constituting an RC (reinforced concrete) structure.

In the figure, what is indicated as a whole by reference numeral 1 is the target prestressed corencrete (hereinafter simply abbreviated as "kat"). The beam I constitutes the concrete structure A together with the pillar 10 that supports it, and the pillar 1 that should support this beam I
0 has already been erected on the ground G. The following method is used to construct the casings 1 on these prefabricated concrete structures, that is, the pillars IO. In addition, in the figures, reinforcing bars are omitted except in FIG. 4, and it is assumed that a second formwork f for forming a frame 1 extending over these columns 10 is attached to each column 10.

First of all, concrete is poured at both ends of the fence 1 to be constructed, at a portion corresponding to one span or a plurality of spans, to form reaction force supports 2 that are integrated with the pillars 10, respectively. At this time, as shown in FIG. 2, norths 3 are buried in two stages, upper and lower, in the area where concrete 1 is to be poured. The north 3 is set to be slightly longer than the reaction support 2 so that its open end may not be blocked by the reaction support 2.

Once the reaction force support 2 is formed, as shown in FIG. The lower parts P CflA N5b are respectively inserted into the lower part of the north 3 and installed between the reaction force supports 2 shown in rj. These P
c The rope material 5 may be a PCC frame rod or the top of a PC steel wire; in this embodiment, a PCC edge wire is used.

After the Pc ropes 5 are erected, reinforcing bars 4 are installed at the connection portions of the beams 1 to be constructed with the columns 10, as shown in an enlarged view in FIG. 3 or 4. This reinforcing bar 1 is formed into a mountain shape in this embodiment, and the portion forming the top of the mountain shape is located at the position where the upper PCQ material 5a is constructed, and the portion forming the bottom portion is located at the position where the upper PCQ material 5a is constructed. Erection of Pc rope material 5b 1
It will be installed to approximately correspond to this position.

Once the reinforcing bars 4 have been installed, as shown in Fig. 3, the fixing device 6 is attached to one end of the P (44 material 5) and the tension gloss 7 is set to the other end, then the PC, M
The material 5 is tensioned by operating the tensioning jack 7. The reaction support 2 acts as a reaction force base for the fixing device 6 and the tension gloss 7, respectively. At this time, if a larger supporting force of the reaction platform is required, underground beams 13 or place materials 14 installed in a normal structure,
Furthermore, it can be reinforced with a wall on the same plane as the place material 14 (even better if it is a seismic wall).

When tensioning the Pc rope 5, the upper Pc rope 5a
The tension of the lower Pc rope 5b shall be smaller than the tension of the lower Pc rope 5b. This is done in accordance with the original purpose of introducing prestress into the beam, that is, the tensile force applied to the lower chord of the beam is borne by the Pc rope.

The tension jack 7 may be one that has been conventionally used in the field when introducing prestress by the Bosttennoyon method. In addition, at this time, the tensioned PC and rope material 5 are temporarily attached with nuts or wedges, etc., and tensioned jacks 7
may be removed.

Once the PCII material 5 has been tensioned, it is then
Concrete 8 (not shown) is poured into a portion located between the two reaction force supports 2 to form a concrete 1. Since the PCM materials 5 are already installed under tension between the two reaction force supports 2, these PCB materials 5 are buried in the concrete 8. Moreover, before pouring this concrete, the above-mentioned upper Pc rope material 5a and lower PCG material 5b may be connected using stirrup bars 11. Note that the reference numeral 12 is a hoop muscle for the column IO.

When the poured concrete has hardened, the tension on the PC rope 5 caused by the tension gloss 7 or the slots and wedges is released, and the fixing device 6 is removed. As a result, bush l-l-s is introduced into the poured concrete 8 on the same principle that push-strain is introduced into concrete by the so-called Pritenoncon method. In other words, the Pc
When the tension is released, a compressive force acts on the rope 5, and this compressive force is introduced into the concrete 8 to which the concrete 8 is attached to the Pc rope 5, that is, prestress. It will be introduced. Also,
After the Pc rope material 5 is stretched, grout is filled in the north 3, and the reaction force support 2 is also subjected to a bushing stress by the so-called Bosttennoyon-Bontoet method. After the concrete 8 hardens, the reaction support 2 becomes integral with the concrete 8 to form the beam l.

The 1st beam constructed using the above 1st method has PC contact materials arranged in upper and lower layers in the thickness direction, so the yield strength of the 1st beam was increased in order to increase the strength of the 9 beams 1. Not only can the weight be reduced, but the rigidity of the wire can be increased to increase its strength against concentrated loads or vibrations caused by earthquakes, etc., and in particular, it can also be used to withstand direct earthquakes. In addition, in keeping with the idea of introducing pressure, stress, and stress, the PCM material should be arranged in a manner that corresponds to the stress generated in the member, that is, in a manner that cancels out the stress generated in the member. For example, if the member is a simple beam, the bending moment is large at the center and the end (supporting end) is In other words, in the vicinity of the pillar, it is ideal to arrange it so that it is located at the upper end.According to the above embodiment, both the part PCI4 material 5a and the lower PC and M materials 5b are in a straight line. Although they are arranged parallel to each other, reinforcing bars 4 as mentioned above are provided at the connection part of 籱 1 with the pillar IO, so the above-mentioned seven points are followed. .

Although this embodiment has been described with respect to a beam of an RC structure, the present invention is not limited to this example, and may of course be applied to a 5RC (steel reinforced concrete) structure. This can be applied to slabs, exterior walls, shear walls, and if necessary, columns.

Mafco, ii? In the embodiment, the reinforcing bars 4 are installed using PC
Although the process is performed after the steel material 5 is installed, the present invention is not limited to this, and may be performed before the PC material 5 is installed.

"Effects of the Invention" As explained above, according to the present invention, tensioning of PCM material can be carried out on site without using a large-scale reaction force table. Moreover, the prestressed concrete (prestressed concrete) structure that was built is made of PC sea bream material or two in the thickness direction! i1]
This increases the rigidity of the structure, reduces the weight of the structure itself, and at the same time increases the strength against concentrated loads and vibrations, eliminating the need for bent R7C steel1).

Furthermore, in most of the structures, buttostress is introduced using the so-called Britten-yon method, which eliminates the hassle of installing a sheath and filling it with grout. It is possible to take advantage of the synergistic effect of improving structural strength and reducing concrete volume, which has an excellent effect of shortening construction period and reducing costs.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention,
Figure 1 is a front sectional view of a concrete structure A in which a concrete structure 1 is in the middle of construction, the second view is a partial front sectional view showing an enlarged reaction force support 2, and Figure 3 is a front sectional view of a concrete structure A in the middle of construction. Fig. 4 is a partial front sectional view showing an enlarged view of the joint between the stressed concrete beam 1 and the column 10.2. ... Reaction force support body, 3. ... Sheath, 4. Reinforcement bar, 5. ... PCp material, tension jack, 10. Column.

Claims (1)

[Claims] In constructing a concrete structure, a method of constructing a prestressed concrete structure having two mutually parallel surfaces on a pre-formed concrete structure and extending between the pre-formed concrete structures, the prestressed concrete structure to be constructed a step of forming reaction force supports that are integrated with the pre-fabricated concrete structure at both ends of the structure, and placing a PC steel material between the reaction force supports so as to be located inside the prestressed concrete structure to be constructed. and a step of arranging and tensioning the PCs in two rows so as to be close to the two parallel surfaces, respectively, and placing the PCs in the two rows at the joint of the prestressed concrete structure to be constructed with the prefabricated concrete structure. A step of providing reinforcing bars between the steel materials, a step of placing concrete to form the intended prestressed concrete structure after tensioning the prestressed steel materials, and a step of placing reinforcement bars between the prestressed steel materials after the cast concrete has hardened. 1. A method for constructing a prestressed concrete structure, comprising the step of introducing prestress into concrete by releasing the prestress.