JP2722209B2 - Precast concrete beams - Google Patents

Description

The present invention relates to a beam made of precast concrete.

(Prior Art) A recess having a U-shaped section is provided at an end of the skeleton at an appropriate length inward from the end face, and a lower streak buried in the skeleton is extended under the recess to the end face of the skeleton. When joining with a column, a reinforcement is provided between the recesses of the opposing beams, or a main reinforcement is provided at the bottom of the end from each recess of the opposing beam to the column-beam joint. Precast concrete beams are known in the art (JP-A-59-118939,
However, in this known example, since the lower struts of the opposing beams are not joined to form a through streak, it cannot be said that there is no anxiety in joining strength.

In addition, a U-shaped cross section extending appropriately inward from the end face is provided at an end of the skeleton, and an end of a beam main reinforcing bar (both an upper bar and a lower bar) embedded in the skeleton is connected to the recess. A precast beam protruding from the end wall to the position of the end face of the skeleton is also conventionally known (see Japanese Patent Publication No. 49-28366). However, this known example is intended for joining beams to each other. In addition, not only the joint with the column is not intended at all, but also the joint work of the lower streaks is difficult due to the presence of the upper streaks when joining the main bars of the beams to form a through bar.

(Object of the Invention) An object of the present invention is to make it possible to easily join the lower ribs of opposing beams to form a through bar when the end is placed on the upper end of the pillar and joined to the pillar. An object of the present invention is to provide a precast beam which can be efficiently and firmly joined to a column.

(Constitution of the Invention) In order to achieve the above object, in the precast beam of the present invention, a U-shaped cross section extending appropriately inward from the end face at the end of the skeleton is provided, and the precast beam is embedded in the skeleton. When the ends of the streaks protrude from the end walls of the recesses as appropriate, and when erected on a column, the corresponding lower streaks of the opposing beams are placed between the end walls of the opposing beam recesses. It can be joined at a position to form a thread.

In the precast beam of the present invention, the protruding length of the lower streak from the end wall of the recess is appropriately selected, and the lower streaks of the opposing beam are connected not only at the column / beam joint but also within the recess. Since the joining can be performed, the joining operation of the lower skeletal muscle is easy, and it is particularly effective when the lower skeletal muscle is a two-stage arrangement.

The joining of the lower stirrups can be either direct joining or indirect joining via a joint bar.

(Description by Drawing) In FIGS. 1 and 2 showing one embodiment of the present invention, 1
Is a precast concrete beam (hereinafter simply referred to as a beam), 2 is a recess provided at an end of the beam 1, 3 is a lower streak buried in the beam 1, and a recess 2 extends inward from an end face of the beam 1. The end of the lower streak 3 has an end wall protruding as needed.

In the figure, reference numeral 4 denotes a rib, and as is apparent from the figure, the upper bar of the beam 1 is arranged above the beam 1.

In the illustrated embodiment, the lower streak 3 has one step, and its protruding length is slightly longer than the length of the recess 2. However, the lower streak 3 may have two steps, and its protruding length is Optionally, it is longer or shorter than that shown, with
May be inside.

When the illustrated beam 1 is erected on a pillar, as shown in FIG. 3, for example, the ends of four beams 1 are placed on a concrete pillar 5 (hereinafter, simply referred to as a pillar 5) and crossed at right angles. The corresponding lower streaks 3 of the beams 1 and 1 facing each other in two directions are welded to each other at the column / beam joint portion 6 via a connecting bar 7 to form a through bar, and then upper streaks are arranged. At the same time, concrete is poured into the upper part of each beam 1 and the column / beam joint 6. At this time, the ribs are arranged also in the recesses 2, but the ribs in the recesses 2 are not shown, but are stored in the recesses 2 until the connection of the main bar 3 is completed. In addition, in the figure, 8 has shown the axial reinforcing bar of the pillar 5.

The case of FIG. 4 corresponds to the case where the projecting length of the lower streak 3 of one of the beams 1 opposed to each other in FIG. 3 is increased by the length of the joint 7. The bars 3 are directly joined to each other at the column / beam joint portion 6 without interposing a connecting bar.

The case where the projecting length of the lower streak 3 of the opposing beams 1 and 1 is longer than the length of the recess 2 and joined at the column / beam joint 6 has been described above. May be shorter than the length of the recess 2 and may be joined via a long joint bar that crosses the column / beam joint 6. In this case, the joint between the lower bar 3 and the joint bar is It will be located in the recess 2.

Next, the erection of the beam in the case where the lower bar 3 has two steps will be described. In the case of FIGS.
The lower lower streak 9 and the upper lower streak 10
Like the lower streak 3 in the figure, it extends slightly forward from the end face of the beam 1, 1, and the corresponding lower streaks 9, 10 are joined to each other at the column / beam joint 6 at the joint bars 11, 12. It is made using.

8 to 10, the opposing beams 1, 1
The lower streak 9 of the lower stage of one of the beams 1 projects long so as to enter the recess 2 of the other beam 1, and the lower streaks 9 are joined to each other in the recess 2 of the other beam 1. The lower struts 10 of the upper stage of the beams 1 and 1 protrude shortly into the recesses 2 of the beams 1, and the lower struts 10 are connected to each other through long connecting bars 13. A weld is located in each recess 2.

Although not shown, the joints of the lower lower muscle and the upper lower muscle are connected in the same manner as the lower muscles in FIGS. 4 and 3, respectively. Figures 8 to
In the case of this two-stage arrangement, if the upper lower streak is extended for a long time, it will hit the lower lower streak when the intersecting beam is erected. So
You should be aware of this, and the order of the lower muscle connections
It is preferable that the joining of the lower stirrups be completed after the joining of the lower stirrups is completed.

(Effect of the Invention) Since the precast concrete beam of the present invention is as described above, when erected on a column, the lower ribs of the opposing beam are securely joined to each other and firmly joined to the column. By properly selecting the length of the lower streaks, the lower streaks can be joined not only at the column / beam joints, but also within the recesses at the beam ends. In particular, various effects such as easy processing when the number of lower streaks is two steps can be expected.

[Brief description of the drawings]

FIG. 1 is a plan view of one embodiment of the present invention, FIG. 2 (a) is an enlarged sectional view taken along the line AA of FIG. 1, and FIG.
FIG. 3 is a plan view showing an installation mode of one embodiment of the present invention; FIG. 4 is a plan view showing a modification of the present invention;
FIGS. 6 and 7 are the same as those of the above-described modification of the present invention (two-step arrangement), FIG. 7 is a sectional view of the modification, and FIGS. FIG. 10 is a cross-sectional view of a plan view showing the manner of erection of reinforcing bars. In the figure, 1: precast concrete beam (beam), 2: recess,
3: Lower bar, 4: Rib, 5: Concrete column (column), 6: Column / beam joint, 7: Splice bar, 8: Shaft bar, 9: Lower bar, 10: Lower bar, 1
1: Joint, 12: Joint.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-B-49-28366 (JP, B1)

Claims (1)

(57) [Claims] An end portion of a frame is provided with a U-shaped recess extending inward from the end face as appropriate, and an end of a lower streak embedded in the frame is appropriately extended from an end wall of the recess. When it is erected on a column, the corresponding lower struts of the opposing beams can be joined to each other at any position between the end walls of the recesses of the opposing beams to form a through bar. Precast concrete beam characterized by the fact that: