JP2006169837A - Column-beam joint structure of reinforced concrete construction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a column-beam joint structure of reinforced concrete construction securing desired strength as a column-beam frame and having excellent workability and economical efficiency. <P>SOLUTION: Columns 10 of reinforced concrete construction, and a PCa member 11 of a beam lower part shorter than a space between the columns 10, with prestress introduced between both ends, are connected and integrated by arranging reinforcements 14 continuous from the PCa member 11 to the columns 10, at a joint part 12 formed between both the columns and PCa member, and integrally placing concrete of the joint part 12, concrete of a beam upper part 15 and concrete of a slab. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a joint structure between a reinforced concrete column and a precast concrete beam.

  Precast concrete (hereinafter abbreviated as PCa) is a reinforced concrete member manufactured in factories, etc., which can achieve high dimensional accuracy and shorten the construction period by eliminating the need for on-site formwork. Since it has the advantage that it can be used, it is widely adopted as various structural members such as columns and beams.

  When connecting such a PCa beam to a reinforced concrete column, a PCa beam generally having a length dimension between columns is manufactured and placed between columns by a support or the like. A method of integration with a pillar or a pillar placed on site is used.

  On the other hand, when a long span structure is adopted in a reinforced concrete frame, a beam using a PCa member into which prestress is introduced is adopted. This beam is obtained by inserting a PC steel material into a PCa member made of high-strength concrete manufactured to a length dimension between columns and introducing a prestress force. According to the beam using the PCa prestressed member, even when the span between columns is long, as shown in FIG. 3, the beam is arranged in a region A where a large tensile stress caused by bending acts on the lower side of the beam. The tensile stress can be opposed to the pre-stress force.

  However, when this type of PCa prestressed member is used as a beam, there is a mixture of column reinforcement, anchorage of beam reinforcement, introduction end of PC steel, etc. in a narrow column beam intersection. In addition, it is very difficult to place concrete and concrete, and there is a problem that the cross section of the portion becomes large.

Then, as a prior art which solves such a problem, the joint part of PCa prestressed reinforced concrete structure of the following patent document 1, for example is proposed.
As shown in FIG. 4, the above-described conventional technique is provided at the lower end of the center between a PCa prestressed reinforced concrete column member 1 in which a part 2 a of a beam protrudes, with a joint 4 having a predetermined length therebetween. A PCa prestressed reinforced concrete beam member 2 in which prestress is introduced into a PC steel bar 3 or the like is arranged, and after joining the reinforcing bars of the beam part 2a and the beam 2 at the joint 4, the joint 4 A concrete having a strength equal to or higher than that of the beam 2 is cast into the two to integrate the two 2 and 2a.
JP-A-5-86643

  According to the structure of the conventional joint described above, since the connection between the beam 2 and the column is performed between the beam part 2a protruding from the column 1 member, complicated bar arrangement work at the column beam crossing portion There is an advantage that becomes unnecessary.

  However, in the structure of the above-described joint portion, the joint portion 4 has a boundary portion between a region A where tensile stress acts on the beam lower side and a region B where compressive stress acts on the beam lower side as shown in FIG. In spite of being a place where a large force does not act, it is formed by placing concrete having a strength equal to or greater than that of the concrete constituting the beam 2 or part 2a thereof. There is a disadvantage that it is inferior.

  Further, since a joint by a gusset plate is formed in a part 2a of the beam around the column member 1 and the joint portion 4, a beam through-hole for penetrating a pipe or a duct can be formed. There is a problem that it is difficult. Further, when the column member 1 is made into PCa, a part 2a of the beam is continuously manufactured, and the shape becomes complicated, and it becomes difficult to manufacture the formwork.

  Furthermore, since the low-strength concrete is generally sufficient for the slab attached to the beam 2, it is inevitably placed after connecting the beam 2 and its part 2a. As a result, a discontinuous joint surface is formed between the part 2a of the beam 2 or the connecting part 4 and the slab, and in some cases, it is necessary to embed dowel reinforcing bars or the like in the joint part. .

  On the other hand, at the intersection of pillars and beams, forces such as compression, tension, and shearing force act in a complex manner, and the beam main bars and hoop bars are complex so that there is a concern about the filling of concrete. It has also been pointed out that shear failure and anchorage failure of the main bars occur depending on the degree of stress at the time.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a reinforced concrete column beam connection structure that can obtain desired strength as a column beam frame and is excellent in workability and economy. Is.

  In order to solve the above-mentioned problem, the invention according to claim 1 is that a reinforced concrete column and a PCa member at the lower part of the beam shorter than the interval between the columns and introduced with prestress between both ends, Reinforcing bars that are continuous from the PCa member to the column are placed in the joint formed at the joint, and the concrete of the joint, the concrete of the upper part of the beam, and the concrete of the slab are integrally cast and integrated. It is characterized by being made.

  Further, in the invention according to claim 2, the PCa member at the lower part of the beam according to claim 1 uses a concrete having a higher strength than the concrete placed on the joint, the upper part of the beam and the slab. It is characterized by this.

  Here, the reinforced concrete columns mentioned in claim 1 include various types of columns such as cast-in-place reinforced concrete, PCa, SRC, etc., and reinforced concrete columns and PCa members below the beam. The joint formed between the two is formed in a region where no tensile stress acts on the lower side of the beam.

  According to the reinforced concrete column-to-beam connection structure according to claim 1 or 2, by using a PCa member at a lower part of the beam that is shorter than the column interval, the entire beam is made into PCa. Since the weight of the part to be converted to PCa is reduced, and a low-capacity lifting machine can be used, construction becomes easy.

  Further, since prestress is introduced between both ends of the PCa member below the beam, it is possible to cope with a long span. At this time, if the prestress is introduced after the PCa is produced at the factory, the prestress introduction work at the site and the installation of the temporary scaffolding for the work are not required, and the joining work is further facilitated. Become.

  In addition, since the joint is integrally formed with the concrete of the upper part of the beam and the concrete of the slab, a discontinuous joint surface is not formed between the joint and the slab or between the beam and the slab. Therefore, it is not necessary to construct a dowel reinforcing bar and the desired strength can be easily ensured.

  According to the invention described in claim 2, high-strength concrete is used for the PCa member at the lower part of the beam to which prestress is introduced, and the stress acting due to the bending force is smaller than that of the lower part of the beam converted to PCa. Since the concrete having lower strength than the PCa member at the lower part of the beam is placed at the joint and the upper part of the beam, the economy is excellent. In addition, a beam through-hole for easily penetrating a pipe, a duct, or the like can be formed by using the above-described joint.

(Embodiment 1)
FIG. 1 shows a first embodiment of a reinforced concrete column beam connection structure according to the present invention. In FIG. 1, reference numeral 10 denotes a reinforced concrete column.
This column 10 is constructed by cast-in-place concrete up to the bottom of the beam, and a PCa member 11 below the beam that is shorter than the interval between the columns 10 is installed between adjacent columns 10. Thereby, between the pillar 10 and the PCa member 11, the junction part 12 which extends from the pillar head 10a of the pillar 10 to the end surface 11a of the PCa member 11 is formed.

Here, the PCa member 11 at the lower part of the beam is made of high-strength concrete, and the PC steel bar 13 is inserted between both ends thereof, and prestress is introduced when the PC steel bar 13 is tensioned. Has been.
And in the junction part 12, the lower main reinforcement 14 embed | buried under the PCa member 11 is extended from the end surface 11a of the said PCa member 11, and is arranged to the column head 10a. Further, above the PCa member 11, an upper main reinforcing bar 17 that is embedded in the beam upper portion 15 and continues to the column head portion 10a of the adjacent column is arranged.

  Further, the joint 12 is formed by placing concrete having lower strength than the PCa member 11 integrally with the beam upper portion 15 and a slab (not shown) on the beam upper portion 15. Thereby, the column 10 and the PCa member 11 at the lower part of the beam are connected and integrated through the joint 12.

  Next, a beam-to-column joining method for obtaining a beam-to-column connection structure having the above-described configuration will be described. First, the column 10 is constructed by in-situ concrete to a position below the beam. On the other hand, in the factory, the PCa member 11 that constitutes the lower part of the beam is made of high-strength concrete, and the PC steel rod 13 is inserted into the insertion hole formed in the PCa member 11, and tension is applied to the PC steel rod 13. After that, the both end portions are fixed to the end portions of the PCa member 11.

  Next, the PCa member 11 obtained in this way is disposed at a predetermined height position between the columns 10 by the temporary support 16, and the lower main reinforcement 14 extending from the end surface 11 a is extended to the column head 10 a of the column 10. Arrange the bars. Next, the upper main reinforcement 17 extending to both the column heads 10a is arranged above the PCa member 11, and the part extending from the end surface 11a of the PCa member 11 to the column head 10a, the part for constructing the beam upper part 15, and the slab type Install a frame. And the pillar head part 10a, the beam upper part 15, the junction part 12, and a slab are formed by placing concrete whose strength is lower than that of the PCa member 11 in these molds.

(Embodiment 2)
FIG. 2 shows a second embodiment of the present invention. The same components as those shown in FIG.
As shown in FIG. 2, in this column beam connection structure, a column 20 made of PCa is used instead of the column 10 shown in FIG. A joint portion 21 is formed between the column heads 20 a of the columns 20 and the end surface 11 a of the PCa member 11.

Here, a reinforcing bar 22a extending from the column head portion 20a of the column 20 is embedded in the joint portion 21, and the end of the reinforcing bar 22a is connected to the lower main reinforcing bar of the PCa member 11 via the fixing hardware 23a. 14. Further, the upper main reinforcing bar 17 is arranged in the beam upper part 15 and both ends thereof are connected to a reinforcing bar 22b extending from the column head 20a of the column 20 via a fixing hardware 23b.
Even in the joint portion 21, concrete having a lower strength than the PCa member 11 is formed by being integrally placed with the beam upper portion 15 and a slab (not shown).

  According to the beam-column joint structure shown in the first and second embodiments having the above-described configuration, the PCa member 11 below the beam is shorter than the interval between the columns 10 and 20, so Since the weight is reduced, it is possible to use a lifting machine having a smaller capacity than the conventional lifting machine, so that the construction is facilitated.

  Further, since the joints 12 and 21 are formed between the column 10 and the PCa member 11 so that the reinforcing bars 14 and 22 that are continuous with the column heads 10a and 20a of the columns 10 and 20 are arranged. There is no crossing of various bar arrangement work etc. in the section, and therefore construction becomes easy.

  Further, since the concrete having lower strength than the PCa member 11 is placed in the joints 12 and 21 and the beam upper portion 15 where the stress acting due to the bending force is smaller than that of the beam lower portion, the economy is excellent. By using the joints 12 and 21, it is possible to easily form a beam through-hole for penetrating a pipe or a duct.

  In addition, since the joint portions 12 and 21 are formed by being integrally formed with the beam upper portion 15 and the slab on the PCa member 11, the joint portions 12 and 21 are discontinuous between the beam upper portion 15 and the slab. Therefore, a construction such as a dowel reinforcing bar is not required and a desired strength can be easily ensured.

  In addition, since prestress is introduced between both ends of the PCa member 11, it is possible to cope with a long span. In addition, since pre-stress is introduced by inserting the PC steel rod 13 in advance in a factory or the like, work such as pre-stress introduction work at the site and installation of a temporary scaffold for that purpose are not required, and the joining work is further increased. It becomes easy.

1 is a longitudinal sectional view showing a first embodiment of a reinforced concrete column beam connection structure according to the present invention. It is a longitudinal cross-sectional view which shows the 2nd Embodiment of this invention. It is a stress distribution map in a column beam frame. It is a longitudinal cross-sectional view which shows the conventional joining structure.

Explanation of symbols

10, 20 Reinforced concrete column 11 PCa member under the beam 12, 21 Joint 13 PC steel bar 14, 17, 22 Reinforcement 15 Beam upper

Claims (2)

  A reinforced concrete column and a precast concrete member below the beam, which is shorter than the column interval and prestressed between both ends, are continuous from the precast concrete member to the column at the joint formed between them. Reinforced concrete column beam connection structure, in which the reinforcing bars are arranged, and the above-mentioned concrete of the joint, the concrete of the upper part of the beam and the concrete of the slab are connected and integrated together .   2. The reinforced concrete column according to claim 1, wherein the precast concrete member at the lower part of the beam is made of concrete having a higher strength than the concrete cast on the joint, the upper part of the beam and the slab. Beam joint structure.

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