JP2011094313A - Method for separately placing concrete in column-beam joint portion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for separately placing concrete in a column-beam joint portion, which enables boundary separation to be easily and securely applied to even a narrow gap between reinforcements in the column-beam joint portion undergoing complicated bar arrangement, which facilitates the removal of a boundary object, and which has high constructibility. <P>SOLUTION: This concrete is separately placed in the column-beam joint portion through: a first step of preassembling the reinforcements in the column-beam joint portion A; a second step of placing column concrete 9 up to a portion under the joint; a third step of injecting a foamed resin material 12a in a fluidized state into the column-beam joint portion by using an upper end surface of the column concrete as a bottom form, and of foaming and solidifying the foamed resin material; a fourth step of placing beam concrete 8 in a portion except the column-beam joint portion by using a foamed and solidified rigid foamed resin 12b as a boundary surface; a fifth step of forming the column-beam joint portion as a cavity S by eluting the rigid foamed resin by means of a solvent 15; and a sixth step of placing high-strength concrete 7 into the cavity. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a concrete placement method for a column beam joint (column beam joint) in a reinforced concrete structure.

  With the revision of the structural calculation standards accompanying the revision of the Building Standards Act in 2006, high-strength concrete is required for the column beam joints in reinforced concrete structures. And, high-strength concrete has higher material costs than ordinary-strength concrete, and it is uneconomical to make high-strength concrete up to columns and beams other than column beam joints. And it was essential to design the other parts as concrete with different strengths and lay them out separately.

  At present, the concrete placement of the column beam joints has a boundary so that the gap between the reinforcing bars is filled with a wire mesh partition material (for example, lath wire mesh or rib lath) or an air fence (air bag). It is formed by a method of forming and placing concrete having different strengths at each boundary.

  However, in these concrete placement methods, wire mesh partitions and air fences are installed in the narrow reinforcing bar gaps of column beam joints where column main bars, beam main bars, hoop bars, stirrups, etc. are complicatedly arranged. The work to do was very troublesome and there was a problem that workability was bad. Moreover, in the method using an air fence, the removal work of the air fence is troublesome, and in the method using a wire mesh partition as a boundary, the removal work is not necessary, but foreign matter remains in the concrete.

  In addition, high strength concrete usually has extremely high fluidity due to the surface-active action of the admixture added, so it is necessary to completely prevent leakage of mortar components in wire mesh partitions and air fences. Is difficult. In the case of a construction procedure in which normal-strength concrete is placed on beams other than the column beam joints, and then high-strength concrete is placed on the column beam joints, with the wire mesh partition as the boundary surface. The mortar component of normal-strength concrete leaks to the inside of the boundary surface (column beam joint), and that portion is not filled with high-strength concrete.

  By the way, according to Patent Document 1 and Patent Document 2, a method for forming a recessed portion for embedding PC steel material on a concrete surface, or a method for installing a fixing bar for a footing on a pile head of an existing pile solidified with cement milk. As a method for forming a cavity, a technique has been proposed in which a hard foamed resin is used, a hard foamed resin is melted with a solvent or heat to form a recess or cavity, and then the recess or cavity is filled with non-shrink mortar or concrete. ing.

  Each of these prior arts uses a melted mold frame made of rigid foam resin that has been foam-molded into a predetermined shape in advance, and this melted mold frame is placed at a predetermined position and melted by a solvent or heat. To form recesses and cavities. Therefore, in these prior arts, it is very easy to form the recesses and cavities by removing the melted mold, but it is difficult to install the melted mold in a narrow and complicated place.

Japanese Patent Publication No. 6-72490 Japanese Patent Publication No. 6-13766

  In view of the above-mentioned present situation, the present invention applies the above-described conventional technique that the formation of a recess and a cavity is easy by removing the melted mold frame made of hard foamed resin, and the column beam joint portion is arranged in a complicated manner. It is possible to easily and surely divide boundaries even in narrow reinforcing bar gaps, and it is easy to remove the boundary and provide a method for placing concrete in the column beam joints that is extremely easy to work with. To do.

  In order to achieve the above object, technical measures taken by the present invention are as follows. That is, the feature of the concrete placing method of the column beam joint according to the first aspect of the invention is that the first step of pre-assembling the reinforcing bars of the column beam joint, and placing the column concrete under the joint A second step of injecting a foamed resin material in a fluidized state with the upper end surface of the column concrete as a bottom mold into the column beam joint and foaming and solidifying, and foaming and solidifying hard foam The fourth step of placing the beam concrete other than the column beam joint with the resin as the boundary surface, and the fifth step of forming the column beam joint in the cavity by melting away the hard foamed resin with a solvent or heat And a sixth step of placing high-strength concrete in the cavity.

  The invention according to claim 2 is the concrete placing method of the column beam joint portion according to claim 1, wherein the first-stage column reinforcement including the reinforcement of the column beam joint portion is provided. It is characterized by pre-assembly.

  The invention according to claim 3 is the concrete placing method for the column beam joint portion according to claim 1, characterized in that only the reinforcing bars of the column beam joint portion are pre-assembled in the first step. Yes.

  According to the first aspect of the present invention, since the foamed resin material in a fluid state is injected into the column beam joint and is solidified by foaming at the column beam joint, the column beam joint is arranged in a complicated manner. Even if the gap is between narrow reinforcing bars, it is possible to easily fill the hard foamed resin without any gaps by allowing the foamed resin material in a fluid state to enter. It is possible to reliably separate the boundaries.

  In addition, since the rigid foamed resin is melted away by solvent or heat to hollow out the column beam joint, it is easy to remove the boundary (hardened foamed resin melted mold) and the bars are complicatedly arranged. The workability is very good, coupled with the ability to easily and reliably fill the hard foamed resin without any gaps even in the narrow gap between the reinforcing bars of the column beam joint.

  Even if a part of the foamed resin material injected into the column beam joint part is foamed and solidified in a state of flowing out to the outside of the column beam joint part, this part is melted away by the solvent or heat to be hollowed out, Since it is replaced with high-strength concrete cast in the column beam joint, it functions on the safe side.

  In the first step, when reassembling the rebar of the column beam joint, the first layer of column rebar including the rebar of the column beam joint is preassembled as in the invention of claim 2. There are cases in which only the reinforcing bars of the column beam joints are pre-assembled as in the invention described in claim 3, and either of them may be adopted.

It is a front view of the reinforcing bar tip assembly explaining the concrete placement method of the column beam joint part concerning the present invention. It is a vertical front view which shows the state which assembled the column form frame and the beam form frame. It is a longitudinal front view which shows the state which laid the column concrete under the joint. It is a vertical front view which shows the state which inject | poured the foamed resin material into the column beam joint part. It is a vertical front view which shows the state which laid beam concrete other than a column beam joint part. It is a vertical front view which shows the state which removed the formwork and melted the hard foamed resin. It is a longitudinal front view which shows the state which laid high strength concrete in the column beam joint part. It is a front view of the reinforcing bar tip assembly showing other embodiments of the present invention. It is a longitudinal front view which shows the state which laid the column concrete under the joint. It is a vertical front view which shows the state which inject | poured the foamed resin material into the column beam joint part. It is a longitudinal front view which shows the state which suspended the precast concrete member with which the column beam joint part was satisfy | filled with the hard foamed resin, and was couple | bonded with the pillar of the lower floor. It is a vertical front view which shows the state which laid beam concrete other than a column beam joint part. It is a vertical front view which shows the state which removed the formwork and melted the hard foamed resin. It is a longitudinal front view which shows the state which laid high strength concrete in the column beam joint part. It is explanatory drawing of the concrete placement method of the column beam joint part which shows other embodiment of this invention. It is explanatory drawing of the concrete arrangement | positioning method of the column beam joint part following FIG.

  Hereinafter, a concrete placement method for a column beam joint according to the present invention will be described. First, in the first step, the reinforcing bars of the column beam joint A are pre-assembled. More specifically, in the embodiment shown in FIG. 1, column reinforcing bars for one layer including the reinforcing bars of the column beam joint A are pre-assembled. This pre-assembly is performed at a low level such as the ground level, then suspended on the site and connected to the previously constructed column reinforcement, and the material reinforcement is brought into the site and constructed in advance. There is a case where pre-assembly is performed on-site while being connected to the formed column reinforcement, and any of them may be adopted.

  In FIG. 1, 1 is a column main reinforcement, 2 is a hoop reinforcement wound around the column main reinforcement group, and 3 is a reinforcement arranged in a state protruding from the column beam joint A by an appropriate length (about 1.5 times the beam formation). The beam main bars 4 are stirrups wound around the beam main bars. Reference numeral 5 denotes a pillar of the lower floor constructed in advance, and reference numeral 6 denotes a beam of the lower floor constructed in advance. 7 is a high-strength concrete placed in the lower-level column beam joint constructed in advance, 8 is a beam concrete other than the column beam joint in the lower floor constructed in advance, 9 is ahead It is a lower-floor pillar concrete constructed by

  Next, as shown in FIG. 2, after arranging the beam connecting to the column beam joint A and assembling the column mold 10 and the beam mold 11, in the second step, as shown in FIG. 3. In this way, the column concrete 9 is placed under the joint.

  Thereafter, as shown in FIG. 4, in the third step, the foamed resin material 12a in a fluid state is poured into the column beam joint A with the upper end surface of the column concrete 9 as the bottom mold, and foamed. Solidify. In this case, since the foamed resin material 12a has appropriate fluidity and viscosity, a part of the foamed resin material 12a injected into the column beam joint A is slightly from the gap between the reinforcing bars to the outside of the column beam joint A. It will foam and solidify in an overflowing state. Reference numeral 13a denotes an injection pump, and a nozzle 13b is provided continuously.

  Then, when the foamed resin material 12a is foamed and solidified, and the column beam joint A is filled with the hard foamed resin 12b, as shown in FIG. 5, in the fourth step, the foamed and solidified hard foamed resin is obtained. Beam concrete 8 other than the column beam joint is placed using 12b as a boundary surface (melted mold).

  Next, as shown in FIG. 6, in the fifth step, the rigid foamed resin 12 b is melted away by a solvent or heat to form a column beam joint in the cavity S. The dissolved liquid is collected in a receptacle 14 temporarily provided around the column and discharged to a tank outside the figure by a hose (not shown) outside the figure. The dissolution of the hard foamed resin 12b may be performed by heating, but in the illustrated embodiment, it is performed by spraying the solvent 15. As the rigid foam resin 12b, rigid foam polystyrene, rigid foam urethane, or the like is used. The solvent 15 may be a petroleum solvent such as benzene, toluene, xylene, gasoline, etc. However, the use of citrus natural limonene is less ignitable than other petroleum solvents, is highly safe, and is colorless. It is desirable in that it is harmless and can reduce environmental impact.

  Thereafter, as shown in FIG. 7, in the sixth step, high-strength concrete 7 having a strength higher than that of the column concrete 9 and the beam concrete 8 is placed in the cavity S, so that the concrete of the column beam joint portion is provided. You will complete the game.

  According to the above configuration, since the foamed resin material 12a in a fluid state is injected into the column beam joint A and is foamed and solidified at the column beam joint A, the column beam joint A is arranged in a complicated manner. Even when the gap is between narrow reinforcing bars, the rigid foam resin 12b can be easily filled without any gaps by allowing the foam resin material 12a in a flowing state to enter, and the column beam joint is formed by the foamed and solidified rigid foam resin 12b. It is possible to easily and reliably demarcate A.

  In addition, since the rigid foamed resin 12b is melted away by the solvent (or heat) 15 and the column beam joint A is hollowed out, it is easy to remove the boundary (hard foamed resin melted mold frame). Even if it is a gap between the narrow reinforcing bars of the column beam joint A, the workability is very good in combination with the ability to easily and reliably fill the hard foamed resin 12b without any gap.

  Even if a portion of the foamed resin material 12a injected into the column beam joint A flows out to the outside of the column beam joint A, this portion is melted away by the solvent (or heat) 15. Since it is made hollow and replaced with the high-strength concrete 7 placed in the column beam joint A, it functions on the safety side.

  8-14 show other embodiments of the present invention. This embodiment is characterized in that the processes from the rebar assembling of the column beam joint A to the injection of the foamed resin material 12a and the foam solidification are performed at a factory or site (a work yard near the construction site).

  That is, in the first step, as shown in FIG. 8, one layer of column reinforcement including the reinforcement of the column beam joint A is preassembled at a factory or site. Reference numeral 16 shown in FIG. 8 denotes a mechanical joint (for example, a grout-type mechanical joint) having one end fixed to the lower end of the column main reinforcement 1.

  In the second step, as shown in FIG. 9, after assembling the column mold 10, the column concrete 9 is placed under the joint.

  In the third step, as shown in FIG. 10, the foamed resin material 12a in a fluid state is poured into the column beam joint A with the upper end surface of the column concrete 9 as the bottom mold, and is solidified by foaming.

  Thereafter, as shown in FIG. 11, a precast concrete member composed of a column beam joint A filled with the hard foamed resin 12b and a single layer of pillars is hung on the site, and is constructed in advance. Combine with the pillars of the floor.

In this state, as shown in FIG. 12, after arranging the beam connecting to the column beam joint A and assembling the beam formwork 11, in the fourth step, the foamed and solidified rigid foam resin 12b is obtained. Interface (
Beam concrete 8 other than the column beam joint is placed as a melted mold.

  Next, as shown in FIG. 13, in the fifth step, the rigid foamed resin 12 b is melted away by the solvent (or heat) 15 to form the column beam joint in the cavity S.

  Thereafter, as shown in FIG. 14, in the sixth step, the high-strength concrete 7 having higher strength than the column concrete 9 and the beam concrete 8 is placed in the cavity S, so that the concrete of the column beam joint portion is provided. You will complete the game. Since other configurations and operations are the same as those of the embodiment of FIGS. 1 to 7, the same reference numerals are given to the same structural members, and description thereof is omitted.

  15 and 16 show another embodiment of the present invention. This embodiment is characterized in that only the reinforcing bars of the column beam joint A are pre-assembled in the first step. That is, in the first step, as shown in FIG. 15 (A), a beam arranged in a state protruding from the column beam joint A by an appropriate length (about 1.5 times the beam formation). The main bar 3, the star wrap 4 wrapped around the beam main bar group, the column main bar 1 slightly protruding up and down from the beam joint A, the hoop bar 2 wrapped around the column main bar group, and one end at the lower end of the column main bar 1 A reinforcing bar tip assembly with a fixed mechanical joint 16 or the like is produced at a factory or site.

  In the second step, as shown in FIG. 15B, the column concrete 9 is driven from the lower end of the mechanical joint 16 to the bottom of the joint to produce a precast concrete member.

  In the third step, as shown in FIG. 15C, the foamed resin material 12a in the fluidized state with the upper end surface of the column concrete 9 in the precast concrete member as the bottom mold is used as the column beam joint. Pour into A and foam and solidify.

  Then, the precast concrete member in which the column beam joint A is filled with the hard foamed resin 12b is hung on the site, and as shown in FIG. 16, it is connected to the lower half column constructed in advance. After that, beam reinforcement connected to the column beam joint A is performed, and the beam form 11 is assembled.

  Although the subsequent steps are not shown in the figure, in the fourth step, the beam concrete 8 other than the column beam joints is cast using the foamed and solidified hard foamed resin 12b as a boundary surface (melting mold), and the fifth step. In the step, the hard foamed resin 12b is melted away by the solvent (or heat) 15 to form the column beam joint in the cavity S. In the sixth step, the column concrete 9 and the beam concrete 8 are placed in the cavity S. Higher-strength concrete 7 with higher strength will be placed. Other configurations and operations are the same as those in the embodiment of FIGS.

  The concrete placing method of the column beam joint part of the present invention can be used for a column beam joint part of a high-rise apartment house or a super high-rise apartment house.

A Column beam joint S Cavity 1 Column main reinforcement 2 Hoop reinforcement 3 Beam main reinforcement 4 Star wrap 5 Column 6 Beam 7 High-strength concrete 8 Beam concrete 9 Column concrete 10 Column form 11 Beam form frame 12a Foam resin material 12b Rigid foam resin 13a Injection pump 13b Nozzle 14 Receiving 15 Solvent 16 Mechanical joint

Claims (3)

  The first step of pre-assembling the reinforcing bars of the column beam joint, the second step of placing the column concrete under the joint, and foaming in the fluidized state with the upper end surface of the column concrete as the bottom mold A third step of injecting a resin material into the column beam joint and foaming and solidifying; and a fourth step of placing beam concrete other than the column beam joint with the foamed and solidified hard foam resin as a boundary surface; The fifth step of forming the column beam joint in the cavity by melting the hard foamed resin with a solvent or heat, and the sixth step of placing high-strength concrete in the cavity. A method for placing concrete in the column beam joint.   2. The method of placing concrete in a column beam joint according to claim 1, wherein in the first step, one layer of column reinforcement including the reinforcement of the column beam joint is pre-assembled.   The method for placing concrete in a column beam joint according to claim 1, wherein only the reinforcing bars of the column beam joint are pre-assembled in the first step.

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