JP2915500B2 - Beam-to-column connection method for precast reinforced concrete structures - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method of joining a precast reinforced concrete structure to a column and a beam, and more particularly to an improvement in a lower end bar of a beam.

[Prior art and problems to be solved by the invention] Conventionally, as shown in Fig. 4, a column head is used as a beam-column joint method of a precast reinforced concrete structure in which a beam reinforcing portion is provided at a beam center portion between columns. After placing the ends of a pair of precast beams in the X direction that are connected to each other by a single-stage beam bottom reinforcement, the other ends of the pair of precast beams in the same Y direction are placed on each other to cross each other. Then, a jointing method is carried out by arranging a beam top reinforcing bar in both XY directions and placing joint concrete at a beam-column joint.

However, in the conventional method, the beams in the X and Y directions are perpendicular to each other, and the lower wires in the X direction overlap each other. When placing the beam, the beam streak is caught by the upper two-step lower streaks of the beam in the X direction and the beam in the Y direction cannot be lowered to a predetermined position, and the lower end streaks of the beam in the X direction must be arranged in one step. I didn't get it.

Therefore, there is a restriction that it cannot be applied to a high-rise building requiring many beam reinforcements.

"Means for Solving the Problems" In order to solve the above-mentioned conventional problems, the present invention relates to a structure in which lower portions of opposed joint end faces are connected to each other by a lower continuous step which is continuous and integral with each other, and The joint ends of a pair of precast reinforced concrete beams facing each other in the horizontal X direction, which are formed by projecting short short two-step bars on the joint end surfaces of the above, are placed on the heads of the columns, and then at the lower ends of the opposed joint end surfaces. The joint ends of a pair of precast reinforced concrete beams facing each other in the horizontal Y direction, which are connected by a lower-end first step and a lower-end step, which are continuously and integrally integrated with each other, are placed on the head of a column. The present invention proposes a beam-to-column joining method for a precast reinforced concrete structure in which an L-shaped reinforcing bar is connected to the tip of a lower-end double-stepped bar in the direction with the tip facing upward.

[Operation] When the beam in the Y direction is placed, the lower step in the X direction is protruded short, so that the lower step in the Y direction does not catch on the lower step in the X direction. The beam in the Y direction can be placed on the pillar without any trouble.

After placing the beam in the Y direction, the lower two-step bar in the X direction joins the L-shaped reinforcing bar to the tip with the bent end of the tip facing upward, so that it is surely attached to the concrete cast at the beam-column joint. Be established.

Therefore, by joining the L-shaped reinforcing bar to the tip of the lower two-step bar of the beam in the X direction, the lower bar can be backed up and down in two steps.

[Embodiment] The present invention will be described below with reference to an embodiment shown in the drawings. A pair of precast reinforced concrete beams 1 and 1 which are arranged at a required interval in the horizontal X direction are connected to each other between the lower portions of the opposing joint end faces. The lower end two-step streaks 3, 3 having at least the minimum required projection length for joining are respectively provided on the joint end faces above the lower end two-step streaks 2, which will be described later. When the beams 1 ', 1' in the Y direction are arranged orthogonally, they are shortly projected so as not to overlap the lower end muscle thereof.

A pair of precast reinforced concrete beams 1 ′, 1 ′ arranged opposite to each other in the horizontal Y direction are connected by a lower two-step lower bar 2 ′ and a lower two-step bar 3 ′ in the lower part between the joint surfaces. .

When joining columns and beams, first, as shown in FIG. 1, the ends of the beams 1 and 1 in the X direction are placed on the heads of columns 4 made of precast concrete or cast-in-place concrete having column reinforcements 5 projecting upward. Then, the ends of the beams 1 ′, 1 ′ in the Y direction are placed on the head of the column 4, and the lower-end single-step streaks 2, 2 ′ are overlapped on each other at right angles.

When the beams 1 ', 1' in the Y direction are placed, since the lower two-step reinforcements 3, 3 'in the X direction protrude in a short length, the lower one-step reinforcement 2' in the Y direction becomes the lower two-step reinforcement 3 '. , 3 'without passing through the gap between the tips, so that the beam 1' in the Y direction
1 'can be placed on the pillar 4 without any trouble.

Next, in this state, the L-shaped reinforcing bar 6 is joined to the distal ends of the lower two-step bars 3, 3 of the beams 1, 1 in the X direction by welding or joint with their bent distal ends facing upward.

After arranging the lower end bars of the beams 1 and 1 ′ in both the XY directions in the upper and lower stages in this way, as shown in FIG.
Reinforcing the upper end bar 7 and casting concrete joints integrally on the beam-column joint and the upper part of the beam 1, 1 '.
And a joint concrete is integrally cast at the joint between 1 'and 1'.

In addition, since the projecting end of the column bar 5 is kept at the upper surface of the beam, the joining work between the lower-end double-step bars 3, 3 and the L-shaped bar 6 can be easily performed without the column bar 5 becoming an obstacle. Can be.

[Effects of the Invention] As described above, according to the present invention, when a beam in the Y direction is placed, no two-step lower reinforcement is provided between the joining end faces of the beam in the X direction. The lower end first step and the lower second step of the step are superimposed orthogonally on the lower step of the beam in the X direction,
The beam in the Y direction can be mounted on the column capital without any trouble.

In addition, since the lower end double bar in the X direction has an L-shaped reinforcing bar joined to its tip and its bent tip facing upward, it is securely fixed to the concrete cast at the joint of the column and beam, and as a beam reinforcing bar Can achieve the reinforcing effect.

Therefore, it is possible to reinforce the strength of the beam-column joint without restriction by arranging the beam bottom reinforcement in two steps at the beam-column joint.

[Brief description of the drawings]

1, 2 and 3 are side views sequentially showing a beam-to-column joining process according to the present invention, and FIG. 4 is a side view showing a state of reinforcing bars at a conventional beam-to-column joint. 1 ... beam in the X direction, 1 '... beam in the Y direction, 2,2' ... lower step first step, 3,3 '... lower step 2 step, 4 ... column, 5 ... column streak, 6 ... L-shaped reinforcing bar, 7.

Claims (1)

(57) [Claims] A horizontal X which is connected between lower portions of opposing joint end surfaces by a continuous lower end single step, and has a short lower end double step protruding from the joint end surface above the lower end single step. The joint ends of a pair of precast reinforced concrete beams facing in the direction are placed on the head of the column, and then the lower end single streaks and the lower end two steps are arranged in a continuous two-step manner between the lower parts of the opposing joint end faces. A joint end of a pair of precast reinforced concrete beams opposed in the horizontal Y direction connected by a streak is placed on the head of the column, and an L-shaped reinforcing bar is bent at the tip of the two-step bar at the lower end in the X direction. A beam-to-column connection method for precast reinforced concrete structures, characterized in that they are joined with their faces facing upward.