JP2907038B2 - Joint structure and joining method between precast beam and column - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for integrally joining a prestressed precast beam to a column and a method for joining the same.

[0002]

2. Description of the Related Art As is well known, a precast beam into which a prestress is introduced can be integrally formed with a member having excellent strength by precasting by autocure curing at a factory, and a tensile strength can be obtained by applying a prestress thereto. Since high-strength beams with excellent strength and bending resistance can be obtained, they are used for various structures such as gymnasiums and warehouses that require a frame with a relatively long span in structure. FIG. 4 and FIG. 5 show a conventional joint structure of this type of precast (hereinafter abbreviated as PC) beam and column. 4 and 5, reference numeral 1 denotes a pillar, and a pair of PCs is provided on an upper surface of the pillar 1.
The ends of the beams 2 and 2 are placed facing each other at a predetermined interval. The PC beam 2 is precast by exposing upper ends 3 and the ribs 4 surrounding the upper ends 3 from the upper surface thereof and extending lower ends 5 from the end surfaces. Yes, PC steel rod 6 inserted linearly inside
, A prestress is applied.

[0003] The PC beams 2, 2 are formed such that the lower end bars 5 extending from the respective end faces are bent upward, and the upper end bars 3,... Concrete is cast between the upper surface of the column 1 and the end surfaces of the PC beams 2 and 2 to be integrally joined. At this time, the floor slab 8 is laid down to the floor level L by also casting concrete on the upper surfaces of the PC beams 2 and 2. The structure in which the PC beam 2 having such a configuration is integrally joined to the column 1 is suitable for constructing a frame having a relatively long span due to the characteristics of the PC beam 2 as described above. Furthermore, there is an advantage that the construction period on site can be shortened as compared with the RC structure in which the entire beam is constructed by cast-in-place concrete.

[0004]

However, in the conventional joint structure between the column 1 and the PC beam 2, the PC beam 2
Is precast with the upper ends of the top bars 3 ... and the ribs 4 exposed from the upper surface over the entire length, so that the floor slab 8 to be laid later by the cast-in-place concrete is precast by the PC steel bar 6. There is a problem in that no stress is applied, and thus the advantage of high strength due to precast and prestress cannot be obtained over the entire cross section of the beam. In addition, although a precast beam is used as the beam, it is necessary to cast the floor slab 8 over the entire length of the PC beam 2 at the construction site. This is one of the factors that hinders shortening,
There is also a problem that the ribs 4 projecting from the upper surface of the PC beam 2 hinder the passage of workers during construction.

SUMMARY OF THE INVENTION The present invention has been made to effectively solve the above-mentioned various problems of the conventional joint structure between a precast beam and a column, and can obtain an excellent strength, a long span and a heavy load. It is an object of the present invention to provide a joint structure and a joint method between a precast beam and a column which can be applied to a structure, can further shorten the construction period, and have excellent construction safety. Things.

[0006]

According to the first aspect of the present invention, there is provided a joint structure between a precast beam and a column, wherein a central portion of the column has a top surface at a top surface and a total sectional area up to a floor level. And prestress is introduced between both end faces.
And the end of the precast beam having a stepped portion where concrete is cut off is exposed until the upper end bar is exposed at the end , and a joint bar is connected to the upper end bar at the inner end of the precast beam. And an anchoring stud is connected to the upper end streak at the outer end, and cast-in-place concrete is cast between the upper surface of the column and the end surface of the precast beam and on the step portion. .

Here, the invention according to claim 2 is characterized in that the precast beam according to claim 1 is prestressed by a PC strand cable inserted between the both end faces. Things.

According to a third aspect of the present invention, in the method for joining a precast beam and a column, after the column is erected, a prestress is introduced into the upper surface of the column, and the central portion includes the upper end streaks and the floor. The end of a precast beam having a total cross-sectional area up to the level and having a stepped portion where concrete is cut off until the upper end bar is exposed at the end, and a lower end extending from the end face of the precast beam A reinforcing bar is arranged in the space between the column and the end surface, a joint bar and a fixing bar are connected to the upper end bar, and then concrete is cast on the end surface of the precast beam and the upper surface of the step, and And the precast beam are integrally joined.

[0009]

[Action] In the invention described in claim 1, there is no notch central portion enclosing the upper muscle and lower muscle, yet
Has a larger cross-sectional area up to the floor level than conventional PC beams
Since it is, and because this large total cross section acts effectively against an external force, the whole PC beam, higher scratch clad force and耐曲can get up force Ruue, between more end faces
Pre-stress has been introduced into the
Accordingly, it can be applied to a structure having a long span and a heavy load. Moreover, since the concrete cast between the end portion of the PC beam and the column is integrated at the end portion of the PC beam, a sufficient joint strength can be ensured even at the joint portion with the column. In addition, the central part of the PC beam has a conventional P
Since the total cross-sectional area larger than that of the C-beam is effective and has high strength, sufficient safety against the work load on the beam can be achieved without the need for the conventional temporary support. Can be obtained.

At this time, the distance between both end faces of the precast beam is
Means for introducing pre-stress into
As in the invention described in 2, both end faces of the precast beam
Prestress by inserting PC strand cable between
It is preferred to add.

According to the method of joining a PC beam and a column according to a third aspect of the present invention, the central portion of the PC beam has a total cross-sectional area up to the floor level including the upper end streaks. In the center part, there is no need to arrange the upper end of the beam or to cast concrete at the construction site, so that the on-site work becomes easier and the construction period can be shortened as compared with the conventional one.

[0012]

1 to 3 show an embodiment of a joint structure between a PC beam and a column according to the present invention. In FIG. 1, reference numeral 10 denotes a pillar, and a pair of PCs is provided on the upper surface of the pillar 10.
The ends of the beams 11, 11 are opposed to each other at a predetermined interval. As shown in FIGS. 1 to 3, this PC beam 11
The upper end muscle 12, the lower end muscle 13 and the rib muscle 14 are arranged inside, and the central portion 15 includes the upper end muscle 12 and the upper rib 14, and the upper surface 16 extends all the way to the floor level L. It is formed to have a cross-sectional area. On the other hand, step portions 17 are formed at both ends of the PC beam 11 by cutting the concrete until the upper end streaks 12 are exposed. The PC beam 11 has both end faces 11a.
Prestress is introduced by applying tension to the PC strand cable 18 inserted in a U-shape therebetween.

The lower strut 13 of the PC beam 11 has an end 11
a of the PC beam 11 whose front end is bent upward while the ends 11a face each other.
At the inner end 11a of the joint, the upper reinforcing bar 12 is connected to the upper reinforcing bar 12 of the adjacent PC beam 11.
9 are connected to each other by being joined to both ends. Further, at the outer end 11a of the PC beam 11 located on the side of the outer pillar 10, a fixing streak 21 is connected to the upper end streak 12, and the tip of the fixing streak 21 is bent downward, and It is fixed on the pillar 10. The connection between the joint muscle 19 and the anchor muscle 21 and the upper muscle 12 is shown in FIG.
In addition to lap splicing as shown in the above, gas pressure welding, enclosed welding or mechanical joint (sleeve joint) can be used. Then, the upper surface of the column 10 and the PC beams 11, 11
Between the end faces 11a of the PC beam 11 and the step 1 of the PC beam 11.
By casting cast-in-place concrete on 7
While the PC beam 11 and the column 10 are integrally joined,
A floor slab 20 is laid on the step 17. In the drawings, reference numeral 22 indicates a column bar, and reference numeral 23 indicates a slab connecting bar.

Next, a method of joining the PC beam and the column having the above-described configuration will be described. First, the upper end muscle 1
2. While arranging the lower muscles 13 and the ribs 14,
The PC strand 11 is formed by arranging the C strand cable 18 in a U-shape in the longitudinal direction. At this time, the PC beam 11
Has a central section 15 enclosing the upper streaks 12 and an upper surface 16 having the entire cross-sectional area up to the floor level L, and concrete at both ends thereof being cut off until the upper streaks 12 are exposed. Mold as follows. Here, the PC strand cable 18 may be arranged linearly below the cross section of the PC beam 11. On the other hand, the pillar 10 is constructed by placing concrete after arranging reinforcement at a construction site or by erection of a PC pillar.

After the column 10 is erected, the ends of the pair of PC beams 11 are placed on the upper surface of the column 10 so as to face each other, and the column 10 and the end surfaces 11a, 11a of the PC beams 11, 11 are placed.
The lower reinforcing bar 13 extending from the end face 11a of the PC beam 11 and bent upward and other required reinforcing bars are arranged in the space between the reinforcing bars. In parallel with this, at the inner inner end 11a of the PC beam 11, the upper end streaks 12, 12 are joined to each other via a joint bar 19, and at the outer end 11a, the anchor streak 21 is attached to the upper end streak 12. Connect. Then
Concrete is cast between the end faces 11a of the PC beam 11 and on the upper surface of the step 17 so that the pillar 10 and the PC beams 11, 11
And are joined together. Thereby, the joining between the column 10 and the PC beam 11 is completed.

According to the joint structure between the column and the PC beam having the above-described structure, the central portion 15 of the PC beam 11 to which the prestress is introduced includes the upper end streaks 12 and the upper surface 16 is at the floor level L. As a result of being formed into a shape having the entire cross-sectional area, the prestress by the PC strand cable 18 effectively acts on the central section 15 of the PC beam 11 over the entire cross-sectional area. For this reason, higher tensile strength and bending resistance can be obtained as the whole PC beam 11,
Therefore, in combination with the high strength peculiar to the PC beam 11, it can be applied to a frame of a structure having a long span and a heavy load. At this time, since a prestress is applied by the PC strand cable 18 inserted into the PC beam 11 in a U-shape, a high prestress can be applied, and thus the prestress is applied to the entire cross-sectional area of the central portion 15 described above. The synergistic effect of being able to effectively exert stress makes the structure more suitable for a structure having a longer span or a heavy load.

In addition, the central portion of the PC beam 11 is
2. As a result of the inclusion of the lower muscle 13 and the rib 14,
Since the entire cross-sectional area is effective and has high strength, sufficient safety can be obtained with respect to the work load on the PC beam 11 without the necessity of a conventional temporary support. It also has the effect that it can be done.

Further, according to the method of joining the PC beam and the column, the central portion 15 of the PC beam 11 has the entire cross-sectional area up to the floor level L including the upper end streaks 12, so that the central portion 15 In No. 15, there is no need to cast a floor slab at the construction site, so that the on-site work becomes easier and the construction period can be shortened as compared with the conventional one.

[0019]

As described above, in the joint structure of the PC beam and the column according to the first aspect, the floor level is larger than that of the conventional PC beam at the central portion of the PC beam against an external force.
In addition to working effectively over the entire cross-sectional area
Therefore, since pre-stress is introduced to the PC beam,
Due to the synergistic effect of the user, it is possible to obtain an extremely high tensile strength and bending resistance as the whole PC beam, and therefore, it is applied to a structure with a long span and heavy load, in combination with the high strength of the PC beam itself. As a result, the central part of the PC beam contains the upper muscle, the lower muscle and the rib muscle,
Since the entire cross-sectional area up to the floor level is effective and has high strength, sufficient safety can be provided for the work load on the PC beam without the necessity of the conventional temporary shoring. Sex can be obtained.

Further, according to the method for joining a PC beam and a column according to the third aspect, the central portion of the PC beam includes the upper end streaks and has a total sectional area up to the floor level. In the central part, there is no need to cast a floor slab at the construction site, so that it is possible to obtain an effect that the on-site work becomes easier and the construction period can be shortened as compared with the conventional one.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of a joint structure between a precast beam and a column according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a side view showing one embodiment of a conventional joint structure between a precast beam and a column.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Column 11 PC beam 11a End face 12 Top bar 14 Rib bar 15 Center part 17 Step 18 PC strand cable 19 Joint bar 21 Anchoring bar L Floor level

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E04B 1/22 E04B 1/16 E04B 1/21

Claims (3)

(57) [Claims] 1. A central part encloses an upper end muscle on an upper surface of a pillar.
And it has a total cross-sectional area to the floor level Te, across surfaces
The prestress is introduced into the precast beam, and the end of the precast beam having a step where concrete is cut off is placed on the end until the upper end bar is exposed , and the end inside the precast beam is A joint bar is connected to the top bar, and an anchor bar is connected to the top bar at the outer end, and cast-in-place concrete is cast between the upper surface of the column and the end surface of the precast beam and on the step. A joint structure between a precast beam and a column, which is provided. 2. The joint structure between a precast beam and a column according to claim 1, wherein a prestress is introduced into the precast beam by a PC strand cable inserted between the both end faces. 3. After the column is erected, a prestress is introduced to the upper surface of the column, the central portion includes the upper end line, has a total cross-sectional area up to the floor level, and the end portion has the upper end line. The end of a precast beam having a stepped portion where concrete is cut off is exposed until the end is exposed, and a lower end bar extending from an end surface of the precast beam is arranged in a space between the column and the end surface. In addition, a joint bar and an anchor bar are connected to the upper end bar, and then concrete is cast on the end surface of the precast beam and the upper surface of the step, so that the column and the precast beam are integrally joined. How to join precast beams and columns.