JPS59228554A - Precast small beam and construction of slab structure using the same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a precast beam for concrete buildings such as condominiums and the like, and a method for constructing a slab structure using the precast beam.

Conventionally, precast beams installed between columns or girders of concrete structures have a structure in which prestress is applied using a boss tension method to reduce deflection.

An example of a conventional precast beam provided with prestress by this type of boss tension construction method will be explained based on FIGS. 1 to 3. The precast beam, which is designated as a whole by reference numeral 1, is made up of a long precast material 2 that has been cast and hardened so that the cross section is square, etc., an end plate 3 that is closely attached to both ends of the precast material 2, and the end plate. -4, an end reinforcing reinforcing bar 5 welded to the end plate 3 and embedded in the precast material 2, and a screw or the like installed between the end plate 3 A sheathed PC steel material 7 whose both ends are fixed to the end plate 3 by the fixing device 6 of
and a large number of stirrup bars 8 arranged around the sheathed PC steel material 7 and embedded within the precast material 2.

In the small beam 1, the sheathed PC
The m material 7 is buried in a downwardly curved state in advance, and after the precast material 2 hardens and develops a predetermined strength, the fixing tool 2 is tightened 4J to give tension horns to the PC steel 4717. As shown in FIG. 3, the flexible shells 1 to 2 are curved upwards. As a result, the force of the pre-casing 1 to the small beam 1 to resist the load from above increases.

In addition, the precast small beam 1 described in 1. is constructed between the large beams 10 or between pillars (not shown), and the gusset plate 4 of A is connected to the 1-1 part of the large beam 10 through the poles 1 to 11, etc.
It is connected and fixed to a gusset plate 13 protruding from the shaped steel 12. After this, a slab formwork (not shown) is attached to the side of the precast beam 1, and the ceiling/floor slab structure 14 is cast, and is integrated with the precast beam 1 to the beam 1.

However, in the conventional precast 1 to small beam 1 described above, a plurality of PC steel members 7 are arranged in the horizontal direction, but only one is arranged in the upper direction. Since the structure is such that the precast material 2 is curved upward by the PC steel material 7, in order to maintain the integrity of the gusset plate 4 and the precast material 2, the end plate 3 to which the gusset plate 4 is fixed has a large number of edge reinforcements. It is necessary to provide reinforcing bars 5. Since welding is generally used to fix these reinforcing bars 5 to the end plate 3, the actual situation is that the work and management thereof is complicated and difficult.

Moreover, FIGS. 4 and 5 show other examples of the conventional precast beam 1. In this example, the gusset plate 4 is directly welded to the end reinforcement reinforcing bar 5 without using the end plate 3. In this case as well, there is a problem that welding the reinforcing bars 5 becomes complicated and difficult.

The present invention was made in order to solve the above-mentioned conventional problems, and there is no need to curve the precast material upward, so the integrity of the plate and the precast material is improved, and the gusset plate The purpose of the present invention is to provide a precast beam that does not require welding end reinforcement reinforcing bars.

Another object of the present invention is to provide a method for constructing a slab structure using the above-mentioned precast 4-beams.

The gist of the precast beam of the present invention is that a part of the gusset 1-play h is buried in both ends of the precast material in the longitudinal direction, and bearing plates that are in close contact with both ends of the precast material in the longitudinal direction are installed in the gusset 1. - at least one pair of sheathed plates fixed to the plate and embedded within said precast material;
cm material is constructed almost parallel to the upper and lower tiers between the bearing pressure plates, and both ends of the sheathed PC steel material are fixed to the bearing pressure plate by respective fixing devices, and after the precast material has hardened and a predetermined strength has been generated. The purpose of the present invention is to apply prestress to the prestressing steel material by the fixing tool.

Moreover, the gist of the method for constructing a slab structure of the present invention is -]
After preparing the precast beams mentioned above in advance at a factory etc.,
The purpose is to erect a large beam at least one space between the pillars at the site, construct a formwork for the slab, and pour the slab to integrate it with the precast small beam.

Hereinafter, the present invention will be described in detail based on an embodiment shown in FIGS. 6 to 9.

The completed precast beam 20 of the present invention includes a long precast material 21 formed with an I film in the shape of a predetermined beam. The precast material 21 is mainly made of concrete as in the past, and also includes main reinforcing bars 21a, stirrup bars 21b, aggregate, and the like.

Parts of the gusset plates 1 to 22 are buried in both ends of the precast material 21 in the longitudinal direction, respectively, and the gusset plates 2
The second part of the sanctum protrudes outward.

In this embodiment, the gusset plate 1 and 22 are made of I'' type steel, and a part of the web 27I located between the upper and lower flanges 23 protrudes to the outside of the precast material 21.

Moreover, bearing plates 25 that are in close contact with both longitudinal end surfaces of the precast material 22 are fixed to the gusset plates 1 to 22, respectively. In this embodiment, the bearing plates 25 are fixed by welding on both sides of the web 24 of the gusset plate 22.

Between the bearing plates 25, sheathed PC steel materials 27, which have entered the sheath 26 buried in the precast material 21, are arranged in pairs in the upper and lower directions in at least one row (two rows in this embodiment) in the lateral direction. It is being constructed. Both ends of the PC steel material 27 are fixed to the bearing plate 2 by known fixing devices 28 such as screws.
It is attached to 5.

The function of the fixing device 28 is to apply tension to the PC steel material 27 after the precast material 21 has hardened to a predetermined strength, thereby imparting prestress to the precast material 21.
do. In this case, the tension of the upper and lower pair of PC steel blades 27 is approximately the same, and the precast material 21 is not bent upward. The reason is that since the PC steel materials 27 are constructed in two stages, upper and lower, it is possible to sufficiently withstand the load from above.

-1- The flexible materials 1 to 20 described above are
The plate 22 was installed protruding from the type 1 steel 30 of the concrete building 29, but set pieces 1 to 31] ~
32 and the like, and then installed between the pillars 29 (or between the girders (not shown)). Thereafter, the ceiling 7-front floor slab structure 33 is placed on the pre-can 1 to the small beams 20.

Next, a method for constructing a slab structure using the precast beams 20 will be described in detail.

First, in order to manufacture the precast beam 20, a formwork (not shown) for casting the precast material 21 into a predetermined beam shape is prepared. Next, gusset plates 22 integral with bearing plates 25 are arranged at both ends in the longitudinal direction of the formwork, and a part of the gusset 1-plate 22 (web 2
4) are exposed from both longitudinal ends of the formwork.

Thereafter, at least one pair of PCi41427 in the sheath 26 is installed vertically between the bearing plates 25, and both ends of the PC steel material are fixed to the bearing plates 25 by fixing devices 28, respectively.

Then, main reinforcing bars 21 are provided around the sheathed PC steel material 27.
a. After arranging the stirrup strips 21b and the like, the precast material 21 is placed in the formwork. Precast material 21
After the predetermined strength is generated after curing, the fixing tool 28
By applying tension to the PC steel material 27, the precast beam 20 is completed.

8- Next, the exposed portions (webs 24) of the gusset plates 22 that are attached to the precast 1 to the small beams 20 are connected to the gusset plates 31 that protrude from the 1-1 type steel 30 of the columns 29 (or large beams, not shown), respectively. The precast beam 20 is connected and fixed to the precast beam 20 and erected at a predetermined position.Then, a formwork for a slab (not shown) is assembled on the side of the precast beam 20, and a slab material is cast on top of it. A ceiling/floor slab structure 33 integrated with the precast 1 to the small beams 20 is formed.

In addition, when installing the precast small beam 20 between 1129, the mounting plate 30a is fixed to the H-beam 30 in advance, and the small beam is attached to the plex V 1 via a spacer as necessary. Place the end of the beam 20 and erect it at a predetermined height.
: It is better to let it go. In this case, it is unnecessary to connect the main reinforcement 21a to the 1-1 type steel 30 of the steel 29. In addition, on the upper part of J, sea urchin, and precast 1 to small beams 20 in Fig. 9,
Goberi stop = 1 Four parts are formed for holding the tipper 34.

Furthermore, the stirrup strips 21b are buried so as to span the inside of the old slab body 33 as well. In addition, conventionally known processing is performed.

As explained above, in the present invention, the precast material 21
Since there is no need to curve the gusset plate 22 upward, there is no mutually separating force between the gusset plate 22 and the precast material 21, and therefore a part of the gusset plate 22 can be directly buried in the precast material 21. . Therefore, the gusset plate 22 can serve to reinforce the end portion of the precast material 21, and there is no need to use a large number of end reinforcing bars 5 as in the conventional case.

Therefore, according to the present invention, there is no need for end reinforcement reinforcing bars, the inconvenience of welding and management thereof is eliminated, and an economical precast beam with good workability and a method of constructing a slab structure using the same are provided. .

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of an example of a conventional precast beam.
Figure 2 is a sectional view taken along the line I-I in Figure 1, Figure 3 is an explanatory diagram of the precast beam in Figure 1 with prestress applied, and Figure 4 is a longitudinal cross-sectional view of a conventional precast beam. , FIG. 5 is a sectional view taken along the line ■-■ in FIG. 8 is a cross-sectional view taken along the line ■--■ in FIG. 7, and FIG. 9 is a cross-sectional view taken along the line IX--IX in FIG. 7. [Explanation of codes] 20...Precast! ~ Small beam 21... Precast material 21a... Main reinforcement 21b... Stirrup bar 22... Gusset plate 23... 7 lunge 24
... Web 25 ... Bearing plate 26 ...
Sheath 27...PC steel material 28...Fixer 29...+130...1-1 type steel 31...Gusset plate 32...Bolt 33.
... Slab structure 34 ... anti-slip roller, ζ -r1')
−． 1X33 Fig. 8, 30S. 11 - ~ G a - - I 27 @ @ 3 -25, b 1 7 @ 28 ~ 21a VI[2゜LIX 23 b 21 □ 9th F

Claims (2)

[Claims] (1) A precast material cast into the shape of a predetermined beam, a gusset plate embedded in both ends of the precast material in the longitudinal direction and with a portion protruding outward from both ends, and the gusset plate. and at least one pair of sheathed PC steel members installed vertically between the bearing plates, and both ends of the sheathed PC steel members. A precast beam characterized by comprising a fixing device that is fixed to each of the bearing pressure plates and applies tension to the precast steel material after the precast material has hardened and has developed a predetermined strength. (2) Prepare a formwork for casting precast material into the shape of a predetermined beam, and place gullet plates integrated with bearing plates at both ends of the formwork in the longitudinal direction. Parts of the formwork are exposed from both ends in the longitudinal direction, and at least a pair of sheathed PC steel members are installed vertically between the bearing plates, and both ends of the PC steel members are attached to the fixing devices, respectively. A precast material is placed in the formwork, and after the precast material hardens and a predetermined strong rebound occurs, the above-mentioned A fixing device applies tension to the precast steel material to form a precast beam, and the exposed portion of the gullet plate in the precast beam is connected and fixed to the type 11 steel of each company or the type 11 steel of the girder, and the precast steel A method for constructing a slab structure using a precast small beam, which comprises constructing a formwork for a slab on the side of the small beam, and then pouring a slab material to integrate it with the precast small beam.