JPH0475328B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a building having a rigid frame structure in the beam direction and a shear wall structure in the beam direction.

[Conventional technology]

Buildings with a rigid frame structure in the direction of the beams and a shear wall structure in the direction between the beams are already known, as are often seen in apartment complexes.

[Problem to be solved by the invention]

In conventional buildings of this type, the load on the girder beams for the long-term design load of the slab is large, and the load on the shear walls is correspondingly small, making it impossible to effectively utilize the support capacity of the shear walls. Also,
High beam construction was also required for the girder beams.

The present invention attempts to eliminate the above-mentioned drawbacks of the conventional example.

[Means to solve the problem]

The technical means taken by the present invention to achieve the above object are as follows. That is, the feature of the present invention is that in a building that has a rigid frame structure in the beam direction and a shear wall structure in the beam direction, the thickness of the slab is thickened only in the central part of the slab in the beam direction, and this thickened slab part The reason is that prestressing was introduced by burying prestressing steel only in the area.

[Effect]

According to the above configuration, prestressing steel is not buried in the slab near the girder beam where it is difficult to introduce prestress, and the slab thickness in this area is thin.
There is no waste of PC steel or concrete, and
Since the prestressed central slab section functions like a kind of wide, flat beam, most of the slab load flows smoothly to the shear wall, reducing the long-term design load borne by the girder beams. will be done.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In the figure, A has a rigid frame structure in the girder direction (Y direction), a shear wall structure in the beam direction (X direction), and slab 1 is made of cast-in-place concrete.
Indicates a multi-story building such as an apartment complex made of PRC (prestressed reinforced concrete). 2 is a column, 3 is a girder, and 4 is a shear wall.

The slab 1 is thickened by an appropriate width (for example, about 1/2 the width of the span between the beams) only in the central part of the two opposing sides, specifically, in the central part in the direction between the beams. be. Then, an appropriate number of strips are installed along the column direction only in this thickened slab portion 1a.
PC steel material 5 is buried to introduce prestress in the column direction. Further, the slab portion 1a is provided with slab reinforcement such as deformed reinforcing bars as necessary, and the thin slab portions 1b on both sides are also provided with slab reinforcement (only distribution reinforcement is sufficient) as necessary.

The slab thickness of the slab portion 1a is, for example, 20 to 23
cm, and the slab thickness of the slab portion 1b is set to about 12 to 15 cm. The beam span is set to 6 to 8 m, and the span between beams is set to 10 to 12 m.

According to the above configuration, the slab portion 1a into which prestress is introduced functions like a wide and flat beam, and most of the slab load is smoothly transferred to the shear wall 4.
The slab load can be effectively supported by the compressive strength of the concrete of the shear wall 4.

As shown in Figures 4 and 5 (lower right), the girder beam 3 only needs to bear part of the load of the thin slab portions 1b on both sides, and the long-term design bending moment of the girder beam 3 can be reduced. Therefore, the beam size of the column beam 3 can be reduced.

Since the prestressing steel material is not buried in the thin slab portions 1b on both sides, there is no tensioning work on the prestressing steel material, there is no waste in the thickness of the slab, and the amount of concrete used and the weight of the slab can be reduced, making it economical.

Furthermore, although this is almost never the case in apartment complexes, in buildings such as factories and warehouses, it may be necessary to form openings in the slab after completion. In such a case, according to the above configuration, the slab portions 1 on both sides
Since the thickness of the slab b is thin and no prestressing steel material is buried, an opening can be easily formed in this slab portion 1b.

Incidentally, when the PRC slab is a slab b in which PC steel materials a are buried substantially uniformly over the entire area as shown in Fig. 5 (upper left), there are the following drawbacks.

Since the PC steel material a... is buried over the entire slab b and at approximately uniform pitches, the fifth
As shown in the figure (lower left), force flows from slab b to beams c..., d... on the four surrounding sides, that is, beam c... located in the X direction (direction perpendicular to PC steel material a...)
The ratio of the long-term design load of the slab borne by the beam d... located in the Y direction (direction parallel to the PC steel material a...) is not much different from that of the RC slab.
Direction perpendicular to the tension direction of PC steel material a (X direction)
A considerable amount of power will flow through the Therefore,
The beam d in the Y direction is required to have a relatively high beam thickness, that is, a large cross-sectional area and a large amount of reinforcing bars, which tends to lack flexibility in structural planning. In particular, in buildings that have a shear wall structure in the X direction and a rigid frame structure in the Y direction, there is a considerable margin in the support capacity of the shear wall against the long-term design load of the slab, but as mentioned above,
If the PC steel materials a are buried at a uniform pitch, a large force will also flow to the beam d in the Y direction, and the load will be borne by the beam d, which will reduce the load on the shear wall. The support strength will not be utilized effectively.

The cross-sectional area of beam d... is much larger than the slab thickness, and therefore the restraint effect by beam d... is large, so prestress is introduced to the slab part near beam d, that is, due to the prestressing steel material a... in this part. Compressing and bending slab concrete is practically difficult, and the PC steel material a buried in the slab portion near the beam d and its tensioning work are wasted.

Because PC steel material a is buried throughout the slab, it is difficult to form openings in the slab, and this is especially important when it becomes necessary to form openings in the slab after the building is completed. I can't.

In order to bend slabs and compress concrete using PC steel material a...
It is necessary to bury ... on the tension side of the concrete slab, that is, near the bottom surface of the slab concrete at the center of the span, and near the top surface at both ends. Therefore, in a PRC slab, the slab thickness inevitably increases in order to ensure the eccentric distance of the PC steel materials a, but as mentioned above, the PC steel materials a are buried uniformly throughout the slab. , it is necessary to thicken the entire slab, which increases the amount of concrete and the weight of the slab, which is uneconomical.

According to the present invention, all of these drawbacks can be eliminated.

In the above embodiments, the PC steel material 5 may be either attached to the concrete or separated from the concrete by a sheath, etc., and the method for introducing prestress may be either pre-tension or post-tension. .

〔Effect of the invention〕

The present invention has the above-mentioned configuration, and since the central slab portion to which prestress is introduced functions like a wide and flat beam, most of the slab load can be smoothly transferred to the shear wall.
The slab load can be effectively supported by the compressive strength of the concrete of the shear wall.

Therefore, it is possible to effectively utilize the generous support capacity of the earthquake-resistant wall, and the load burden from the girder beams can be reduced accordingly, making it possible to reduce the beam size of the girder beams, which is very economical.

[Brief explanation of drawings]

1 to 5 show examples of the present invention, in which FIG. 1 is a schematic cross-sectional view of a building seen from the row direction, FIG. 2 is a schematic cross-sectional view taken along the line - in FIG. FIG. 1 is a schematic sectional view taken along the line --, FIG. 4 is an operational diagram, and FIG. 5 is an explanatory diagram for explaining the operational effects of the present invention. 1...Slab, 1a...Thick slab part, 1b
...thin slab parts on both sides, 3... girder beams, 4...
...Shear wall, 5...PC steel material.

Claims (1)

[Claims] 1. In a building with a rigid frame structure in the beam direction and a shear wall structure in the direction between the beams, the thickness of the slab is increased only in the central part of the slab in the direction between the beams, and prestressing steel is buried only in this thickened part of the slab. A structure of a construction characterized by introducing prestress.