JPH06316966A - Structure of beam-column joint - Google Patents

Abstract

(57) [Summary] [Purpose] In the structure of a beam-column joint using a half precast member for a column that incorporates shear reinforcement bars for X-shaped reinforcement, the weak point is the connection of the X-shaped reinforcement. In addition, the pillars and beams can be joined firmly to improve the yield strength of the building. [Structure] A column half precast member A composed of a tubular precast concrete 1 in which a shear reinforcing bar group B of an X-shaped bar is embedded, and first and second steel annular panels 3a, 3b provided at both upper and lower ends thereof. Are vertically arranged concentrically, the ends of the shear reinforcing bar group are connected to each other inside the column-beam joint panel zone, and project from the steel cylinder body 4 that can be fitted into the tubular precast concrete and its outer surface. A steel beam-column joint body C made up of the cross-beam steel frame end portion 5 thus formed is provided on the outer periphery of the beam-column joint panel zone, the lower end of the steel cylinder is supported by the first steel annular panel, and the upper end is It is arranged in a state of being fitted with the second steel annular panel, the steel tubular body is welded to at least one of the first and second steel annular panels, and concrete is placed inside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a beam-column joint using a column half precast member having an X-shaped bar arrangement.

[0002]

2. Description of the Related Art The present inventor has made a group of shear reinforcing bars, which are X-shaped reinforcing bars intersecting in an X-shape in a side view, in a tubular precast concrete having a circular hole in the axial direction formed in the center thereof. The vertical middle portion is exposed inside the circular hole,
Japanese Patent Application No. 4-8157 has already proposed a tubular half-precast member for a column, which is embedded in a state in which both ends in the up-down direction are projected from the upper and lower end surfaces of tubular precast concrete.

Since this half-precast member for a column has an X-shaped rebar, RC for a horizontal load during an earthquake is used.
It has been experimentally confirmed that the yield strength of the column can be significantly increased.

Further, in this half-precast member for pillars, since the vertical middle portion of the shear reinforcing bar group which is the X-shaped bar is exposed inside the circular hole, concrete is cast on site inside the circular hole. When this is done, this concrete will be integrated with the surrounding tubular precast concrete via the above-mentioned exposed shear reinforcing bar group.

Therefore, in this half-precast member for a pillar, the vertical pillar main bars which are parallel bars and the hoop bars which surround them are buried in the wall thickness of the tubular precast concrete. Compared with the half precast member for columns, it has an advantage that the tubular precast concrete and the cast-in-place concrete cast in the circular hole at the center are surely integrated.

However, this half-precast member for a pillar has the following problems, and therefore, although it has the excellent advantages as described above, an actual working example has not yet been seen. First, in the structure of a typical beam-column joint where the main beam reinforcement was fixed to the concrete in the beam-column joint panel zone, no matter how much the column's proof strength is increased by the X-shaped reinforcement, it will be horizontal during an earthquake. This is because the beam main bar slides in the longitudinal direction of the beam main bar with respect to the concrete in the column-beam joint panel zone due to the load, which does not lead to an improvement in the yield strength of the building. Secondly, in general, the connection between the upper and lower column main bars in the RC column is performed at a position about 1 m above the floor surface, that is, when a bending moment acts on the column, so that the connecting portion does not become a weak point in strength. , It is performed at the position where it becomes an inflection point between the compressive force and the tensile force acting on the column main bar, but in the case of X-shaped bar arrangement, the tensile force acts over the entire length of the diagonal bar, so it is connected at a high position from the floor surface. Then, the connection portion becomes a weak point, and a general connection method in RC pillars cannot be adopted.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above situation, and its object is to make the connecting portion of the rebar, which is an X-shaped rebar, weak in strength. Another object of the present invention is to provide a structure of a column-beam joint so that the column and the beam can be firmly joined and the yield strength of the building can be improved.

[0008]

[Means for Solving the Problems] The technical means taken by the present invention to achieve the above object are as follows. That is, the structure of the column-beam joint according to the present invention is a group of shear reinforcing bars formed into an X-shaped bar crossing in an X-shape in a side view on a tubular precast concrete in which a circular hole in the axial direction is formed in the center. The intermediate portion in the vertical direction is exposed inside the circular hole, both end portions in the vertical direction are embedded in a state of protruding from the upper and lower end surfaces of the tubular precast concrete, and the upper end of the tubular precast concrete is more than the tubular precast concrete. Providing a first steel annular panel with a large outer diameter,
At the lower end, the column half precast members, which are provided with a second steel annular panel having the same outer diameter as the tubular precast concrete, are vertically arranged concentrically, and in the column-beam joint panel zone, Steel consisting of steel cylinders that connect the ends of the shear reinforcing bar groups in the upper and lower half precast members for pillars and can be fitted into the tubular precast concrete, and girder end steel frames protruding from the outer surface thereof Of the column-beam joint body of the above, on the outer periphery of the column-beam joint panel zone, the lower end of the steel cylinder is supported by the first steel annular panel of the lower column half precast member, and the upper end is Arranged in a state of being fitted with the second steel annular panel in the upper half precast member for a pillar, and welding the steel tubular body and at least one of the first and second steel annular panels, Previous It is characterized in that the interior of the steel tube of circular holes and Column Joint of the central pillar for Precast members are to Da設 concrete.

[0009]

According to the above construction, since the ends of the shear reinforcing bar groups in the upper and lower post-column half precast members formed into the X-shaped bar are connected inside the column-beam joint panel zone, the connecting portion is It does not become a weakness of the X-shaped reinforcing bar. Welding may be used as the connecting means between the reinforcing bars inside the column-beam joint panel zone, but if mechanical joints (joints having a diameter larger than that of the reinforcing bars) such as lock nut joints and crimp joints are adopted, The mechanical joint functions as an anchor at the end of the rebar of the X-shaped bar, and the original mechanical characteristics of the X-shaped bar are effectively exhibited.

The girder is made of steel, and a steel beam-column joint body comprising a steel-cylindrical body that can be fitted into tubular precast concrete and a girder-end steel frame that projects from the outer surface of the girder is connected to the beam-column joint. On the outer periphery of the partial panel zone, the lower end of the steel cylinder is supported by the first steel annular panel in the lower pillar half precast member, and the upper end is the second steel in the upper pillar half precast member. It is arranged in a state of being fitted with a ring-shaped panel made of steel, and the steel tubular body and at least one of the first and second steel ring-shaped panels are welded to each other, and a circular hole in the center of the half precast member for pillar and Since concrete was placed inside the steel cylinder of the column-beam joint, the concrete in the panel-beam joint panel zone was restrained by the steel cylinder of the column-beam joint, and the connection between the girder steel frame and the column was It is done firmly.

[0011]

1 to 3 show an example of a column half precast member A having an X-shaped bar arrangement. The half-precast member A for columns is manufactured by the centrifugal molding method,
Reference numeral 1 is a tubular precast concrete having a circular cross section in which a circular hole 2 in the axial direction is formed in the center. Within the wall thickness of the tubular precast concrete 1, a shear reinforcing bar group B, which is an X-shaped bar crossing in an X-shape in a side view, has its vertical middle portion exposed inside the circular hole 2. It is buried in the state. The construction surface of the X-shaped bar formed by a pair of diagonal lines a and b intersecting the X-shape in a side view is vertical (parallel to the axis of the tubular precast concrete 1), and Plural pairs are arranged symmetrically around the axis of the tubular precast concrete 1. The upper and lower ends of all the diagonal stripes a and b are bent vertically. Although the deformed bar may be used as these rebars, the threaded bar is used in this embodiment.

As shown in FIG. 1, the shear reinforcing bar group B is a pre-assembled rebar having a drum shape (a shape in which the upper and lower ends are thick and the central portion is thin). In the center of the group B, as shown in FIG. 3, a space S in the vertical direction, which is larger than the outer diameter of a concrete casting pipe (Tramie pipe or the like) not shown, is formed.

1 and 2 is a first steel annular panel having an outer diameter larger than that of the tubular precast concrete 1 fixed to the upper end of the tubular precast concrete 1, and 3b is a tubular precast concrete. 2 is a second steel annular panel having an outer diameter equal to that of the tubular precast concrete 1 fixed to the lower end of 1. Small holes for inserting reinforcing bars are formed in the first and second steel annular panels 3a and 3b, and the upper and lower ends of the shear reinforcing bar group B are inserted into these small holes.

First and second steel annular panels 3a, 3b
When assembling the pre-assembled rebar of the shear reinforcing bar group B,
The role as a connecting member for fixing the upper and lower ends of the reinforcing bar by welding, adhesion, fastening of nuts (not shown), etc. together.
A role as a driving form for the end face when centrifugally molding the tubular precast concrete 1, and a role as a curing member that prevents damage to the end of the manufactured tubular precast concrete 1 due to contact with another object. In addition, the first steel annular panel 3a also serves as a support member for supporting the steel column-column joint body C described later at a predetermined position.

As shown in FIG. 4, the steel column-beam joint C can be fitted into the tubular precast concrete 1, that is, the inner diameter is slightly larger than the outer diameter of the tubular precast concrete 1, and The steel tubular body 4 is set to have a smaller diameter than the outer diameter of the first steel annular panel 3a, and a plurality of girder end steel frames 5 projecting from the outer surface of the steel tubular body 4. Reference numeral 6 shown in FIG. 4 is a half precast member A for upper and lower columns,
It is a lock nut joint which is an example of a mechanical joint connecting the ends of the shear reinforcing bar groups B in A in the column-beam joint panel zone, and is composed of a long nut 6a and a pair of lock nuts 6b, 6b. Has been done.

Next, the structure of the beam-column joint and its construction procedure will be described. As shown in FIG. 4, the column half precast members A, A are arranged concentrically, and as shown in FIGS. 4 and 5, inside the column-beam joint panel zone P, the columns on the upper and lower floors. The end portions of the shear reinforcing bar groups B, B of the half precast members A, A are connected by a lock nut joint 6.

Next, as shown in FIG. 4, the column-beam joint body C is dropped from the stigma and placed on the outer periphery of the column-beam joint panel zone. In this state, as shown in FIG. 6, the lower end of the steel tubular body 4 is in contact with the upper surface of the first steel annular panel 3a of the pillar half precast member A on the lower floor and is supported at a predetermined level. As shown in FIGS. 6 and 7, the upper end side of the steel cylinder 4 has a half precast member A for pillars on the upper floor.
Is fitted into the second steel annular panel 3b, and is prevented from moving in the horizontal direction.

In this state, as shown in FIG. 6, the first steel annular panel 3a and the steel tubular body 4 are fixed to each other by welding W, and then, as shown in FIGS. Concrete D is cast in-situ into the circular holes 2 and 2 in the center of the half precast members A and A and the steel cylinder 4 of the column-beam joint C.

On the girder steel frame, at an appropriate time, as shown in FIG.
As shown in FIG. 5, the deck plate 7 is laid, floor reinforcement is performed, and floor concrete 8 is placed. In the above embodiment, the pillar half precast members A may be hung and connected to the site one by one, or two or three layers may be connected in advance in a factory or a work yard near the site,
This may be suspended in the field and connected. Although not shown, in addition to the above-mentioned shear reinforcing bar group B, a plurality of vertical rebars arranged in parallel and hoop bars surrounding them may be embedded in the wall thickness of the tubular precast concrete 1. .

10 and 11 each show another embodiment of the present invention. In the embodiment shown in FIG. 10, the steel cylindrical body 4 of the column-beam joint body C
It is characterized in that the upper end portion of is welded to the second steel annular panel 3b of the half precast member A for columns on the upper floor. The lower end of the steel tubular body 4 is welded to the first steel annular panel 3a of the half precast member A for columns on the lower floor by welding W.
However, this welding W may be omitted. In the embodiment of FIG. 11, the outer peripheral surface of the first steel annular panel 3a has a stepped shape, and the lower end portion of the steel tubular body 4 is fitted into the small diameter portion of the first steel annular panel 3a. It is characterized in that it is configured to be prevented from moving in the horizontal direction and to be supported at a predetermined level by the large diameter portion of the first steel annular panel 3a. The other structure is the same as that of the embodiment of FIG. 6 or FIG.
The description is omitted.

In each of the above embodiments, in the inside of the column-beam joint panel zone P, the end portions of the shear reinforcing bar groups B and B in the half precast members for columns A and A on the upper and lower floors. Although the lock nut joint 6 is used as a means for connecting each other, it is also possible to adopt another connecting means such as a crimp joint or welding.

[0022]

According to the present invention, the ends of the shear reinforcing bar groups in the upper and lower half column precast members having the X-shaped bar arrangement are connected to each other inside the column-beam joint panel zone. Therefore, the connection part does not become a weak point,
Moreover, if a mechanical joint such as a lock nut joint or a crimp joint is adopted as a connecting means between the reinforcing bars inside the column-beam joint panel zone, the mechanical joint functions as an anchor at the end of the reinforcing bar of the X-shaped bar. As a result, the mechanical characteristics inherent to the X-shaped bar arrangement can be effectively exerted. Further, a steel beam is used as the girder, and a steel beam-column joint body made of a steel tubular body that can be fitted into a tubular precast concrete and a girder end steel frame that projects from the outer surface of the steel beam is used. On the outer periphery of the panel zone, the lower end of the steel cylinder is supported by the first steel annular panel in the lower pillar half precast member, and the upper end is made of the second steel in the upper pillar half precast member. Arranged in a state of being fitted with an annular panel, the steel tubular body and at least one of the first and second steel annular panels are welded together, and a circular hole and a column in the center of the column half precast member Since concrete was placed inside the steel cylinder of the beam joint, the concrete in the column-beam joint panel zone was restrained by the steel cylinder of the pillar-beam joint, and the connection between the girder steel frame and the column was strong. And the proof stress of the building Get boss.

[Brief description of drawings]

FIG. 1 is a perspective view of a half precast member for a column having an X-shaped bar arrangement.

FIG. 2 is a schematic vertical sectional side view of a half precast member for a pillar.

FIG. 3 is a horizontal cross-sectional plan view of a half precast member for a pillar.

FIG. 4 is a perspective view illustrating a structure of a beam-column joint portion.

FIG. 5 is a vertical cross-sectional side view of essential parts in a state where upper and lower half precast members for columns are connected.

FIG. 6 is a vertical cross-sectional side view of a main part in a state where a steel beam-column joint body is attached.

FIG. 7 is a cross-sectional plan view of a main part in a state where a steel column-beam joint body is attached.

FIG. 8 is a vertical cross-sectional side view of a main part when concrete is cast on site.

FIG. 9 is a cross-sectional plan view of a main part in a state where concrete is cast in situ.

FIG. 10 is a vertical cross-sectional side view of essential parts showing another embodiment of the present invention.

FIG. 11 is a vertical cross-sectional side view of a main part showing another embodiment of the present invention.

[Explanation of symbols]

 A ... Half precast member for column, B ... Shear reinforcing bar group, C ... Column-beam joint body, D ... Concrete, P ... Column-beam joint panel zone 1 ... Cylindrical precast concrete, 2 ... Circular hole, 3a ... No. 1st steel annular panel, 3b ... 2nd steel annular panel.

Claims (1)

[Claims] 1. A tubular precast concrete having a circular hole in the axial direction formed in the center thereof, and a shear reinforcing bar group which is an X-shaped bar crossing in an X-shape in a side view, and an intermediate portion in the vertical direction of the group. The first steel having a larger outer diameter than the tubular precast concrete, which is exposed inside the circular hole and is embedded in a state where both end portions in the vertical direction project from the upper and lower end surfaces of the tubular precast concrete. A half precast member for a column, which is provided with an annular panel made of steel and has a second steel annular panel having an outer diameter equal to that of the tubular precast concrete at the lower end, is vertically and concentrically arranged, and a beam-column joint is formed. Inside the panel zone, the ends of the shear reinforcing bar groups in the upper and lower half column precast members are connected to each other and can be fitted into the tubular precast concrete. A steel beam-column joint body consisting of a steel cylinder and a large-beam end steel frame protruding from the outer surface of the steel-beam joint is provided on the outer periphery of the beam-column joint panel zone, and the lower end of the steel cylinder is a lower pillar. The steel tubular body, which is supported by the first steel annular panel of the half precast member for a vehicle, and is arranged such that the upper end is fitted to the second steel annular panel of the upper half precast member for a pillar. And at least one of the first and second steel annular panels are welded, and concrete is placed inside the circular hole in the center of the column half precast member and the steel cylinder of the column-beam joint body. The structure of beam-column joints characterized by the presence of