JP4255522B2 - Beam-column joint structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a beam-column joint structure, and more particularly to a beam-column joint structure in a transition floor of a structural type in a mixed structure in which a lower floor is a precast reinforced concrete structure and an upper floor is a steel structure.
[0002]
[Prior art]
For example, in order to realize the design requirements of providing a space with a large beam span on the upper floor or reducing the weight of the upper floor, the lower floor is a reinforced concrete (RC) structure and the upper floor is a steel frame (S) The structure may be a mixed structure.
In such a mixed structure, when designing the entire building as an integrated ramen structure, for example, it is necessary to ensure that stress is transmitted on the transition floor from the lower floor of the RC structure to the upper floor of the S structure. There is. In order to realize the S structure that is mechanically continuous with the RC structure, the steel column connected to the top end of the RC column is designed to be rigidly connected to the RC column. Various types of fixed column bases having a rigid connection structure, such as conventional embedded column bases and exposed fixed column bases, are known.
Also, in order to ensure the accuracy of the construction of the upper-level steel frame, the steel frame is embedded in the RC column in advance, and the steel frame embedded in the transitional floor and the column base of the S column may be designed to be rigidly connected. Many.
[0003]
[Problems to be solved by the invention]
However, in the above-described design, it is necessary to embed a steel frame that is not considered in the column design in the RC column, and there is a problem that the entire steel material usage amount increases and the construction of the RC column becomes complicated.
In addition, if it is an exposed fixed column base with high rigidity, the column section of the lower floor is determined by the column dimensions built in the upper floor, so the column section of the lower floor must be larger than the required design dimension, It becomes uneconomical.
[0004]
Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, and is composed of an economical member structure, and a beam-column joint structure that can be easily and accurately constructed of a steel column on an upper floor. Is to provide.
[0005]
In order to achieve the above object, the present invention provides a beam-column joint structure of a transition floor of a mixed structure in which a lower floor is a precast reinforced concrete structure and an upper floor laminated on the lower floor is a steel structure. A steel beam block joint beam bracket was joined to the side surface at a predetermined position near the top edge of the precast reinforced concrete column block concrete where the steel column was erected , and a bottom diaphragm and a concrete filling hole were formed An upper surface diaphragm closes the upper and lower surfaces, and a box joint portion in which a steel column block having the same shape as a steel column on the upper floor is provided on the upper surface diaphragm is provided, and the precast reinforced concrete structure is provided around the box joint portion. Steel with ribs on the inner surface so that it is approximately equal to the outer dimensions of the pillar block concrete It is a column beam joint structure that is surrounded by a closing plate and is filled with concrete between the steel plate closing plate and the box joint and in the box joint, and the column beam joint is integrally formed. The reinforcing bar fixing plate is fixed to the upper end of the column main reinforcement of the precast reinforced concrete extended from the lower floor to the space between the box joint and the closing plate, and the upper end of the main column reinforcing bar to which the reinforcing bar fixing plate is fixed Is embedded in the concrete above the upper end of the closing plate to form the column beam joint .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the column beam joint structure of the present invention will be described with reference to the accompanying drawings.
1 to 3 are a perspective view, a front view, and a front view showing a steel unit 10 composed of a joint steel frame 11 and a column main reinforcement 2 that are assembled in advance in a factory and embedded in precast concrete (hereinafter referred to as PCa) column parts. It is a top view. As shown in FIG. 1, three deformed reinforcing bars serving as the column main reinforcement 2 of the PCa column 1 on the lower floor are arranged at four corners of the column cross section, respectively, and the helical hoop reinforcement 3 so as to surround the column main reinforcement 2 at the four corners. Is arranged. On the other hand, a reinforcing bar fixing plate 4 is fixed to the upper end of the column main reinforcement 2. The reinforcing bar fixing plate 4 holds the position of the column main reinforcing bar 2 located near the top end of the PCa column 1. In the present embodiment, a steel plate having a side of 10 cm is nut-fixed (not shown) to the head of each column main reinforcement 2.
[0010]
The joint steel frame 11 shown in FIG. 4 is built so as to be surrounded by the upper ends of these column main bars 2 and to match the lower and upper column cores and the beam installation height for the upper floor slab. . This joint steel 11 has a box joint 12 equal to the outer dimension of the upper-layer steel column 21 shown by phantom lines in FIG. 4 and two through diaphragms 13 and 14 that block the upper and lower joint openings of the box joint 12. And a beam bracket 15 to be joined to the side joint of the box joint portion 12 and a steel column block 16 which is erected on the diaphragm 13 and has the same outer dimensions as the upper-layer steel column 21. In the present embodiment, the PCa pillar 1 has an outer dimension of □ 850 × 850, while the box joint 12 constituting the panel zone has an outer dimension of □ 500 × 500. The box joint 12 is made of a steel plate processed material, but may be a pre-made square steel pipe having a predetermined size. The beam bracket 15 is made of built-up H-section steel, and the steel column block 16 is made of a ready-made box column (□ 500 × 500). As the steel material, an SN material that meets the design specifications is used.
[0011]
In FIG. 1, the steel column block 16 is shown by phantom lines in order to clearly show each configuration, but in reality, it is welded to the upper surface diaphragm 13 as shown in FIGS. 2 and 4. Each figure shows an example of a T-shaped joint having beam brackets 15 attached to the three side surfaces of the box joint 12. However, a cross-shaped beam joint can be configured like a general inner pillar. Needless to say. At this time, the details of the connection of the beam bracket 15 on the beam joint side are omitted for simplification of the drawing, but can take a known shape.
[0012]
As shown in FIGS. 1 and 3, a concrete filling hole 13 a is formed in the center of the upper surface diaphragm 13. Internal concrete is placed in the box joint 12 through the concrete filling hole 13a. Note that air vents (not shown) are formed at the four corners of the diaphragm in order to reliably fill the concrete.
[0013]
Further, the box joint portion 12 as a panel zone has a quadrangular shape in plan view, and the side surface is covered with a rectangular tube-shaped closing plate 20 having one side equal to the column outer dimension. A ribbed steel plate is used for the closing plate 20. The ribbed steel sheet has a predetermined shape of ribs continuously formed on the entire surface of one side, and is bent into a rectangular tube shape so that the surface with the ribs is on the inner surface side. The height of the closing plate 20 is set equal to the web height of the joint portion of the beam bracket 15. Since the ribs are arranged on the inner surface side of the closing plate 20, the concrete filled in the panel zone is surely integrated with the PCa column 1 and the column main reinforcement 2 under the beam, and the split crack failure between the concrete and the reinforcement, Prevent pulling out. In this embodiment, a ribbed steel plate having a thickness of 12 mm is used. However, a plate having a thickness that does not deform even when subjected to a side pressure of the filled concrete can be used as appropriate.
[0014]
FIG. 5 is a schematic perspective view showing a configuration of a joint structure of a PCa column, an S column, and a beam, which is completed by placing concrete from the steel material assembly state of FIG. 1 in a factory. In order to perform concrete placement as shown in the figure, first, the concrete unit is inserted into the box joint 12 from the concrete filling hole 13a with the steel unit 10 incorporating the joint steel 11 in a predetermined position of the column upright. Perform placement. Further, the steel unit 10 is placed horizontally, and a part of the formwork (not shown) corresponding to the side surface and the top end surface of the PCa column 1 is assembled to the outside of the steel material unit 10 to perform concrete placement of the entire PCa member. As a result, it is possible to complete a joint structure with high manufacturing accuracy in which the PCa pillar 1 part, the joint panel zone part, and the PCa pillar top end part (steel column base part) are integrated.
At this time, the closing plate 20 functions as a side mold of the joint panel zone, but a normal temporary mold can be used instead of the closing plate 20. In this case, it is preferable to design a panel zone that does not take into account the confining effect of the concrete by the closing plate 20.
[0015]
In the above description, the diaphragm attached to the upper and lower ends of the box joint and the beam flange are welded as an example of a so-called diaphragm penetration type, but the diaphragm is built in the upper flange position of the beam as a column penetration type, You may make it weld a beam joint to the column side surface. Similarly, a stiffener type can be used.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional perspective view showing an embodiment of a beam-column joint structure according to the present invention.
FIG. 2 is a front view of the beam-column joint structure shown in FIG.
3 is a plan view of the beam-column joint structure shown in FIG. 1. FIG.
FIG. 4 is a perspective view showing an overall shape of a joint steel frame.
FIG. 5 is a perspective view showing the shape of a column beam joint structure in a completed state.
[Explanation of symbols]
1 Precast concrete pillar (PCa pillar)
2 Column Main Reinforcement 4 Reinforcement Fixing Plate 10 Steel Unit 11 Joint Steel Frame 12 Box Joint 13, 14 Diaphragm 13a Concrete Filling Hole 15 Beam Bracket 16 Steel Column Block 20 Closing Plate

Claims (1)

The precast reinforced concrete structure in which the lower-level floor is a precast reinforced concrete structure and the upper-level floor stacked on the lower-level floor is a mixed-structure transitional beam-column joint structure in which the steel columns of the transitional floor are erected At the predetermined position near the top end of the pillar block concrete , the steel beam block joint beam bracket is joined to the side surface, and the upper and lower surfaces are blocked by the lower surface diaphragm and the upper surface diaphragm formed with the concrete filling hole, A box joint having a steel column block having the same shape as the upper-layer steel column is erected on the upper diaphragm, and the outer periphery of the box joint is approximately equal to the external dimensions of the column block concrete of the precast reinforced concrete structure. So that the inner surface is surrounded by a steel plate closing plate with ribs formed on the inner surface, It is a column beam joint structure in which concrete is filled between the box joints and in the box joints, and the column beam joints are integrally formed, and from the lower floor, the box joints and A reinforcing bar fixing plate is fixed to the upper end of the main column reinforcement of the precast reinforced concrete extended to the space between the closing plate, and the upper end of the main column reinforcement to which the reinforcing bar fixing plate is fixed is above the upper end of the closing plate. A beam-column joint structure characterized in that the beam-beam joint is embedded in the beam-beam joint.

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