JPH08239901A - Mixed construction of reinforced concrete column and steel girder - Google Patents

Abstract

PURPOSE: To make use of PC concrete column incorporating a girder steel in an appropriate section having appropriately arranged reinforcements in accordance with a design possible while shortening time required for joining by a method wherein a welding joint is used for joining the PC concrete column incorporating the steel girder to a ground floor column. CONSTITUTION: A ground floor column, with an upper bed plate 3A embedded in its upper end, in a height approximately half the height of a story is erected on a ground floor. A PC concrete column 1 incorporating a steel girder 2 in a height corresponding to the height of 1-3 stories is installed on top of the ground floor column, and temporary joining is made by bolting with steel plates for temporary joining welded to steel plates 5 embedded in four sides on the upper end of the ground floor column and the lower end of the PC concrete column held from both sides with splicing steel plates. An intermediate steel girder is installed between the incorporated steel girders 2, and joining is made by bolting or welding, or by using both means together. Then, joining is made by welding on four sides where the upper bed steel plate 3A of the ground floor column and the under bed steel plate 3B of the PC concrete column 1 are in contact with each other. As occasion demands, the steel plates for temporary welding are severed by melting and removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixed structure of a reinforced concrete column and a steel beam of a high-rise building.

[0002]

2. Description of the Related Art In the construction of middle- and high-rise buildings, from the viewpoint of rationalization of construction and economical efficiency, a reinforced concrete structure effective for compressive force is used as a pillar, and a light-weight steel frame structure capable of forming a long span is used as a beam. Has been receiving more and more attention in recent years. As the reinforced concrete columns, in addition to cast-in-place reinforced concrete, so-called precast concrete columns with built-in steel beams, which are integrally precast with the ends of the steel beam at the time of manufacturing the precast reinforced concrete columns, are also adopted.

[0003]

A conventional precast concrete column with a built-in steel beam frame is manufactured in a structure in which a sleeve is embedded in the lower end and the column main bar projects from the upper end. The pillar main bar protruding from the column is inserted into the sleeve at the lower end of the upper floor, the upper floor pillar is built, and then grout material is injected into the sleeve. It is being appreciated. In this sleeve joint method, it is necessary to keep the number of sleeves embedded in the lower end of the column equal to the number of column main bars protruding from the upper end of the column, but the outer diameter of the sleeve is considerably larger than that of the column main bar. Since it is large, the number of buried bars is limited, and only that number of column main bars can be arranged. On the other hand, if an attempt is made to increase the number of column main bars, the number of sleeves must be increased accordingly, and thus the cross-sectional area of the column must be unnecessarily increased. In this way, the sleeve joint system imposes great restrictions on the number of column main bars and the cross section of the column. Further, since it takes a curing time for each layer to develop the strength of the grout material of the sleeve joint, a long time is required for the construction.

[0004]

The present invention follows the conventional method of adopting a precast concrete column with a built-in beam steel frame as a reinforced concrete column, while changing the structure of a conventional precast concrete column with a built-in beam steel frame to a sleeve joint. Instead, the use of welded joints eliminates the above restrictions on precast concrete columns with built-in steel beams and enables the use of precast concrete columns with built-in steel beams that have an appropriate cross-section and reinforcement according to the design. At the same time, the purpose is to shorten the joining work time.

That is, the present invention uses, as a reinforced concrete column, a precast concrete column with a built-in beam steel frame, in which steel plates are embedded at both upper and lower ends and which is precast integrally with the ends of the steel frame beam. After that, the upper and lower beams of the precast concrete columns with built-in steel frames are joined by welded joints at the middle part of the floor height, and the mixed structure of reinforced concrete columns and steel beams, where the middle parts of the steel beams are joined between the built-in steel beams .

A first point of the present invention is to manufacture and use a precast concrete column with built-in beam steel frame having a completely different structure from the conventional precast concrete column with built-in beam steel frame.

A structure in which a sleeve is embedded in the lower end of a conventional precast concrete column with a built-in steel beam and the main bars of the column project from the upper end is stopped, and steel plates are embedded in both the upper and lower ends. The embedded steel plates are exposed on the upper and lower end surfaces of the precast concrete columns with built-in beam steel.

The precast concrete column with built-in beam steel may be any of a reinforced concrete column, a prestressed concrete column and a prestressed reinforced concrete column. In reinforced concrete columns, both ends of the main bar of the column are welded and tightly bonded to the steel plates at the upper and lower ends, and in the case of prestressed concrete columns, both ends of PC steel material are similarly introduced after tension is applied.
It is fixed on the steel plates at the upper and lower ends. However, in the case of prestressed reinforced concrete columns in which PC steel and column main bars are mixed, in order to prevent the introduction of tension force into PC steel,
The short column main bars are welded to the steel plates at the upper and lower ends, respectively, and the long column main bars are arranged between them to be connected by a lap joint.

Further, the precast concrete column with a built-in steel beam frame has a hollow cross-section excluding the joint with the built-in steel beam, so that the weight of the column can be reduced and the concrete can be saved.

A second important point of the present invention is that the welded joint portion between the precast concrete column with the lower beam girder steel frame and the precast concrete column with the upper girder steel beam is used as the middle part of the story height.

This is because the middle part of the story height is considered to be the site where the stress generated in the column is the smallest. Due to the structure of the frame and the structure of the precast concrete column with a built-in beam steel frame, it is preferable to provide a welded joint at the site where the stress is the smallest during design.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing the embodiments of the present invention.

FIG. 1 is a process vertical sectional view showing a construction procedure of an example of a mixed structure of a reinforced concrete column and a steel beam of the present invention. Although FIG. 1 shows a precast concrete column with two built-in steel beams, precast concrete columns with three and four built-in steel beams are also constructed in exactly the same manner.
The construction procedure will be described with reference to FIG.

(1) A pillar whose height is about half of the floor height is constructed on the foundation floor. An upper end steel plate 3A is embedded at the upper end of this pillar. The foundation floor columns may be constructed with either precast concrete columns or cast-in-place concrete.
(Fig. 1 (a)) (2) A precast concrete pillar 1 containing a steel beam 2 is built on the foundation floor pillar, and the precast concrete pillar 1 is temporarily joined to the foundation floor pillar. As an example of this temporary joining method, as shown in FIGS. 2 (a) and 2 (b), the steel plate 5 for temporary joining is attached to the steel plates 5 embedded in the upper end of the foundation floor column and the four side faces of the lower end of the precast concrete column 1. Although a method is used in which the upper and lower temporary joining steel plates 7 are welded and bolted while being sandwiched between the steel plates 8, other methods may be used for temporary joining. (Fig. 1 (b)) In Fig. 1 (b), an example of using the precast concrete column 1 with built-in beam steel frame having a length of two layers (floors) is shown, but the length of the precast concrete column 1 with built-in beam steel frame is shown. The size does not have to be two layers (floors), but may be one layer (floors) or three layers (floors) depending on the manufacturing conditions of the precast concrete columns with built-in beam steel and the transportation environment.

(3) The middle portion 4 of the steel beam is built in, and the built-in steel beam 2 is bolted or welded, or jointly used, and the joint portion of the pillar is the contact portion between the upper end steel plate 3A and the lower end steel plate 3B. Weld the four laps of and make the main connection. If necessary, the temporary joining steel plate 7 is melted and removed.

By repeating (2) and (3), the mixed structure with the steel beam is completed.

A floor slab is constructed on the steel beams 2 and 4 by an ordinary method.

In FIG. 2 (a), in addition to the above-mentioned temporary joining method, when PC steel rods are arranged in the precast concrete column 1, the end states of the PC steel rods 9 are fixed to the upper and lower steel plates 3A and 3B. Are also shown. In addition, in FIG.
An example of the arrangement of the column main bars of a prestressed reinforced concrete column in which C steel rods (not shown) and column main bars coexist is shown, and a short column main bar 12A is used for the upper end steel plate 3A and the lower end steel plate 3
It is welded to B, and long column main bars 12B are arranged between them and connected by a lap joint.

[0019]

According to the present invention, by adopting a welded joint instead of a sleeve joint of a precast concrete column with a built-in beam steel frame, the limitation of the number of column main bars and the unreasonable increase of the column cross section are eliminated, and the design is improved. The correct cross section,
This enables the use of precast concrete columns with built-in beams and steel frames that have appropriate reinforcement, and shortens the time required for joining work.

[Brief description of drawings]

FIG. 1 is a process vertical sectional view showing a construction procedure of an example of a mixed structure of a reinforced concrete column and a steel frame beam of the present invention.

2A and 2B show a joint portion of a precast concrete column with a built-in beam steel frame used in the present invention, in which (a) and (c) are longitudinal sectional views and (b) are transverse sectional views.

[Explanation of symbols]

1 ・ ・ Precast concrete columns, 2 ・ ・ Built-in steel beam, 3A ・ ・ Upper steel plate, 3B ・ ・ Lower steel plate, 4 ・ ・ Middle steel beam, 5 ・ ・ Embedded steel plate, 6 ・ ・ Anchor bar, 7 ・ ・
Temporary joining steel plate, 8 ... current steel plate, 9 ... PC steel rod, 10 ...
・ Main welded part, 11 ・ ・ Hollow part, 12A ・ ・ End column main bar,
12B ... Main pillar of middle section.

Claims (1)

[Claims] 1. As a reinforced concrete column, a precast concrete column with a built-in steel beam and a steel frame embedded in the upper and lower ends and precast integrally with the ends of the steel beam is used. A mixed structure of reinforced concrete columns and steel beams, in which the precast concrete columns with built-in steel beams are joined by welded joints at the middle of the floor height, and the intermediate portions of the steel beams are joined between the built-in steel beams.