JPH0781355B2 - Construction method of joist slab using precast concrete girder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for constructing a joist slab structure using a precast concrete girder.

(Conventional technology) The structure of a building is composed of columns, beams, floors, walls, etc., and the structure includes reinforced concrete, reinforced steel-framed concrete construction, steel-framed construction, etc. Is done by. In the above-mentioned structure and industrialized construction method, pillars are erected at regular intervals, large beams are bridged between the pillars, small beams are bridged between the large beams, and the floor slab is supported flatly on the large beams and small beams. ing. In forming the floor slab, a part of industrialized construction method is adopted.

For example, there is a slab construction method in which a prestressed semi-precast concrete joist slab is framed on a large beam and in-situ concrete is cast on the upper surface of the semi-precast concrete joist slab to be integrated.

As shown in FIGS. 10 and 11, the frame structure of the slab is used to form a girder G having a cross section of the remaining girder h ₂ obtained by subtracting the thickness h _{1 of the} joist slab from the girder h of the girder. Assemble the cross beam formwork.

The semi-precast concrete joist slab b
₁ (hereinafter referred to as semi PC Joyce Tosurabu) is subtracted thickness h _r of the joists (joists) b ₃ and field hitting set to slab concrete of a predetermined slab thickness h ₀ projecting inverted trapezoid at regular intervals on the slab bottom surface semi PC slab b ₂ and the half precast concrete Joyce Tosurabu b ₁ (hereinafter half formed integrally
It is called PC Joyst Slab). The semi PC Joyce Tosurabu b ₁ is caused to the truss muscle arranged truss muscle joists (joists) in its production process (Mukuri)
The concrete is placed and molded by raising the above, and the support work is unnecessary when the concrete is erected on the girder 1. In addition, in FIG. 10, the left side of the center line XX is a cross-sectional view taken along the line EE of FIG. 11, and the right side is the cross-sectional view taken along the line of FIG.

The frame structure of the girder and the joist slab forms a form by the bottom form a ₂ and side form a _{1 of} the remaining beam formation h ₂ cross-section obtained by subtracting the thickness h _{1 of the} joist slab from the beam formation h of the girder. The half PC joist slab b ₁ on the side form a ₁ between the facing girders.
And close the gap formed between the side mold a ₁ , joist b ₃ and half PC slab b ₂ with a form a ₃ (shaded area in Fig. 11) or other means. Beam reinforcement on the girder, slab reinforcement on the cast-in-place slab r, concrete is placed, and cast-in-place slab r is applied to the cross beam G and the semi-PC joist slab b _1.
The large beam and the joist slab are framed together.

(Problems to be solved by the invention) In the conventional method, it takes a lot of time to form and dismantle the beam forming section of the remaining beam formed by subtracting the thickness of the joist slab from the beam forming of the large beam, and the supporting work is performed on the form. It is necessary, and as the floor height rises, the construction of shoring work becomes a large scale.

Also, when the span between beams becomes long span, the joist (small beam) of the half PC joist slab is formed (the gap formed between the joist b ₃ and the half PC slab b ₂ corresponds to the height of the formwork).
Occlusion of higher becomes mold a ₃ part is increase the construction cost becomes increasingly complicated. Furthermore, if the span between the beams constructing the joist slab becomes a long span, it will correspond to the floor load of the joist slab.
Assembling of the PC joist slab The prestress amount is greatly increased by increasing the truss reinforcement, so the amount of slab deformation after placing concrete on site is large, and bending stress is applied to the large beams and the ends of the joist slab, causing cracking.

The present invention is proposed in view of the above problems of the prior art, and its object is to omit a formwork and a supporting work as a precast concrete beam for a large beam on which a half PC joist slab of a joist slab is mounted. However, the purpose is to reduce the labor required for on-site construction and shorten the construction period, and further to provide a method of framing the precast concrete girder and joist slab that reinforces the joint between the girder and joist slab to prevent cracking.

(Means for Solving the Problems) In order to achieve the above-mentioned object, according to the method for framing a joist slab using a precast concrete girder according to the present invention, the cross section of the girder from the height S of the first floor of the structure Between the precast concrete columns or cast-in-place concrete columns C of height S ₁ excluding the growth height S ₂ , the beam growth height of the large beam section
A hanging recess having a beam height S ₃ of a cross section excluding the slab height S ₄₁ of the joist slab R from S ₂ and each end of the joist portion 4 of the semi-precast concrete joist slab B hanging on the beam side surface. The precast concrete joist slab B is constructed by constructing a precast concrete girder A lacking 1 and then forming a semiprecast concrete slab part 4a and a joist part 4 on the lower surface of the slab between the facing girders A. Each end of the portion 4 is fitted and erected in the hanging recess of the girder A, and a beam upper main bar 11 is arranged on the upper surface of the girder A in the beam longitudinal direction. And the slab reinforcement bar 12 for reinforcing the in-situ concrete on the upper surface of the semi-precast concrete joist slab B, and then the cutout part 5 at each end of the joist part 4 The slab concrete 13 is placed on the upper surface of the semi-precast concrete joist slab B and the upper surface of the precast concrete girder A.

According to the invention of claim 2, a semi-precast concrete joist slab is provided at each end portion of the joist portion 4 in the semi-precast concrete joist slab B facing each other with a precast concrete joist A having a recess 1 for hanging on the side surface of the girder. A notched portion 5 having an open upper surface and an end portion is provided, and a gate-shaped reinforcing bar 10 is arranged between the notched portions 5 so as to straddle the top portion of the girder A.

According to the invention of claim 3, the precast concrete girder A is provided with a recessed portion for hanging 1 on which each end of the joist portion of the semi-precast concrete joist slab B is hooked on the side surface of the beam, and The main bar and the U-shaped ribs 3 are buried, and the upper end hook portion 31 of the U-shaped auxiliary bar is projected from the beam top surface.

According to the invention of claim 4, in the semi-precast concrete joist slab B, an assembled truss reinforcement is arranged in the joist portion, and the upper chord member 6 of the truss reinforcement is embedded so as to project from the upper end and the truss is provided. The bent end portions of the lower chord member 8 of the muscle are connected to the cutout portions 5 at the respective end portions of the joist portion 4.
Anchor 8a projects inside.

(Operation) Since the present invention is configured as described above, a precast concrete girder (hereinafter referred to as a PC girder) is erected between precast concrete columns or cast-in-place concrete columns, and is hung on the side surface of the PC girder. Half with a recess for
The joist part of the PC joist slab is hung on the same recess for hanging, and the beam main bar is arranged on the upper surface in the beam longitudinal direction of the PC girder.
After arranging the slab reinforcing bars that reinforce the cast-in-place concrete on the upper surface in the longitudinal direction of the beam and the upper surface of the semi-PC joist slab, the upper surface of the semi-PC joist slab, each joist end groove and the top of the PC girder are simultaneously concreted. By joining, the semi-PC joist slab and the PC girder are integrally joined, and the joist slab is constructed using the PC girder in this way, and the form frame for filling the joist part by PC conversion of the girder is formed. Assembling and dismantling of the formwork including is omitted, and furthermore, half-PC joist slab is made into PC without erection of support under the beam
It can be installed on a large beam.

According to claim 2, a hanging concave portion for hanging the joist portion of the half-PC shoist slab is provided on the side surface of the PC girder, and the cutout portion provided in the joist portion of the half-PC joist slab is for hanging the girder A. It is mounted so that it fits in the concave portion 1, fits in the same portion, and straddles the top of the PC girder between the joist end cutouts of the semi-PC joist slabs that face each other across the PC girder. By arranging a gate-shaped reinforcing bar with and fixing it in the cutout part, by placing concrete on the upper surface of the half PC joist slab, each joist end cutout part and the top of the PC girder at the same time,
The PC joist slab and the PC girder are integrally joined, the PC girder and the joist slab are framed, and the joists of the PC joist slab are rigidly joined, and the horizontal rigidity performance of the joist slab is improved, and the joist slab and Prevents cracking at the joints of PC girders.

According to claim 3, the joist part of the half-PC joist slab can be mounted by providing a hanging recess for hanging the joist part of the half-PC joist slab on the PC girder. By embedding the ribs and projecting the U-shaped upper end hooks of the ribs, the beam upper main bars are arranged in the beam longitudinal direction of the upper end hooks, and the portal-shaped ribs are arranged on the upper end hooks. Then, they are restrained to form beam rebars and become integral with the concrete that will be placed later.

According to claim 4, in the assembled truss reinforcement arranged in the joist portion of the half-PC joist slab, the upper chord member of the truss muscle projects to the upper end surface of the half-PC joist slab, so that the half-PC joist slab upper surface is punched later. The half PCT joist slab and the cast-in-place slab concrete become integral as a shaky concrete of the slab concrete that is constructed by the cast in-situ to secure the rigidity, and further, the lower chord of the truss muscle is in the cutout part of the end of the joist part. It becomes exposed and becomes an anchor, and the gate-shaped reinforcing bar arranged across the top of the PC girder is fixed and becomes integral with the concrete that will be placed later,
Conventionally, the joint parts of adjacent half-PC joist slabs, which used to be pin joints, become rigid and bear the stress of floor load.

(Examples) The present invention will be described below with reference to illustrated examples.

Fig. 5 is a vertical sectional view corresponding to the first floor of the building. The building consists of a PC girder A horizontally mounted between pillars C and a half-PC joist slab B erected between opposite girders A. , Consists of the Joyst Slab R, which is an integral part of the concrete cast concrete slab 13 on the same half PC Joist Slab B.

The height S ₁ of the pillar C is a height obtained by subtracting the height S ₂ of the girder A from the height S of the first floor, and is composed of a precast concrete pillar or a cast-in-place concrete pillar. (See FIG. 5) FIG. 4 is a plan view of FIG.
The surface is shown, PC girder A is erected between the opposing pillars C, and half the number of PCs are divided between the opposing PC girders A.
The joist slab B is erected, and the joist slab R is constructed by integrating the cast-in-place concrete slab 13 on each half-PC joist slab B as described above.

FIG. 6 is a partially enlarged perspective view of the PC girder A installed between the pillars C. As shown in FIG. 2, the beam cross section has a beam height S ₃ obtained by subtracting the slab thickness S ₄₁ of the joist slab R. The side surface of the beam has a recess 1 for hanging the joist portion 4 in the half-PC joist slab B. (See FIGS. 1 to 4) 2 is a beam lower main bar, 3 is a U-shaped rib having an open upper end surface, which is projected on the upper surface of the beam at regular intervals, and the upper end is bent like a hook. There is. In the figure, 31 is a rib bar hook.

7 to 9 show the structure of the joist slab R,
Half-PC joist slab B and cast-in-place concrete slab 13
It is composed of.

The half-PC joist slab B is formed of a half-PC slab 4a and a joist portion 4 on the lower surface of the slab. The joist portion 4 is embedded with truss reinforcements along its length, and the truss reinforcements are the upper chord members 6 and the lower chords. It is formed in a truss shape composed of a member 8 and a diagonal member 7 connecting the upper and lower chord members, and a part of the upper chord member 6 and the diagonal member 7 protrudes above the half PC slab 4a surface. In the figure, 2 is a reinforcing bar of the cast-in-place concrete slab 13. Further, 9 is a metal fitting for joining the upper chord member and the diagonal member 7 arranged to each other, and 4b is a reinforcing bar of the half PC slab 4a.

Further, the semi-PC joist slab B is provided at the end of the joist part 4 with a cutout 5 that opens to the upper surface and the tip, and the peripheral cutout 5 has the end 8a of the lower chord member 8 of the truss line in a vertical direction. It is bent upward to form an anchor member.

Then, the PC girder A is formed from the height S of the first floor of the building to the girder.
PC column or cast-in-place concrete column C with height S ₁ minus S ₂
The semi-PC joist slab B is mounted between the opposing PC girders A so that the cutout portion 5 of the joist portion 4 of the slab B fits into the locking recess 1 of the PC girder. Then, as shown in FIG. 1, the gate-shaped reinforcing bar 10 straddles the apex of the PC girder A across the cutouts at the ends of the half-PC joist slab B facing each other across the PC girder A. Is provided, and the missing portion 5
The lower chord member 8 is fixed to the end portion 8a constituting the anchor.

Next, as shown in FIG. 3, the upper main bars 11 of the girders of the girders are arranged in the longitudinal direction of the PC girder A at the ends of the rib bar hooks 31 projecting at regular intervals with the upper surface of the PC girder A open. A gate-shaped rib 32 is arranged between the open upper end portions of the muscles 3 to close the upper open portion of the ribs 3 and is orthogonal to the half PC slab 4a surface and the PC girder A upper surface X, Reinforcing bars for cast-in-place concrete slabs in Y direction
After arranging 12, half-PC slab 4a, joist part 4 missing part 5 and the upper part of PC girder A, at the same time, concrete is poured, and on-site concrete slab 13 is installed, and half-PC joist slab B and The joist slab R and the PC girder A, which are integrally joined to the PC girder A, are constructed.

As described above, according to the embodiment, the girder is the PC girder A, and the joist portion of the half-PC joist slab B is hung in the hanging recess 1 of the PC girder A. As a result, the formwork of the girder including the formwork for filling the joist part is omitted, and the supporting work is also unnecessary, and the joist part 4 of the half-PC joist slab B is further provided with the cutout part 5 to form the PC girder. The aforesaid cut-out portion 5 facing across A
In addition to the end 8a of the lower chord member 8 of the joist part 4 with the reinforcing bar 10, the cast-in-place concrete slab 13 including the upper surface of the PC girder A is fixed.
By arranging the slab reinforcement bar 12 on the above, and by constructing a cast-in-place concrete slab 13 in the same part, the half-PC joist slab B and the PC girder A are integrally joined, and the joist slab R and the PC girder A are framed. , The horizontal rigidity performance of the joist slab R is improved, and the occurrence of cracks at the joint between the joist slab R and the PC girder A is prevented.

(Effect of the invention) According to the present invention, as described above, the height S of the first floor of the building is
From the girder section RyoNaru height S ₂ the height S ₁ except for girder cross-section bridges the precast concrete column or field hitting concrete pillars RyoNaru height relative precast concrete girders A height S ₁ except for S ₂ The joist slab is erected on the girder A by fitting the ends of the joist portion of the semi-precast concrete joist slab arranged between the girders A into the hanging recesses formed on the side surfaces. Since it is configured as above, there is no need to assemble and dismantle the girder formwork as in the prior art, and further, it is not necessary to erect a support, which greatly saves on-site work and saves construction cost.

Further, since the end portion of the joist portion fitted into the hanging concave portion on the side surface of the girder A in the half-PC joist slab is provided with a cutout portion that is open to the upper surface and the end surface, a reinforcement bar is provided in the cutout portion. By arranging and arranging concrete, the large beam A and the semi-PC joist slab can be more surely and integrally joined.

The invention of claim 2 uses the cutout portions at the ends of the joist portion of the half-PC joist slab, and between the cutout portions of the pair of half-PC joist slabs facing each other across the girder A. After arranging reinforcing bars straddling the girder A over the apex and arranging slab reinforcing bars between the half PC joist slabs, each upper end of the girder A and the joist part are provided with a cutout portion and the half PC joist slab. By placing concrete on the top, the large beam A and half PC
By joining the joist slabs together, the horizontal rigidity of the slab can be improved and the occurrence of cracks can be prevented.

In the invention of claim 3, a beam lower end bar and a U-shaped rib are embedded in the girder A, and an upper end hook portion of the rib is projected from the beam top surface to achieve integration with post-cast concrete,
The semi-PC joist slab is erected on the girder A without support because the recess for hanging the joist end of the semi-PC joist slab is omitted on the side surface of the member.

According to the invention of claim 4, the upper chord member of the assembled truss reinforcement embedded in the joist portion of the semi-precast concrete joist slab is made to project to the upper surface of the slab,
By integrating the post-casting concrete with the lower truss member of the assembled truss bar, the joist part and the girder A can be integrally joined by projecting the lower chord member into the cutout part of the joist end. is there.

[Brief description of drawings]

1 and 2 are vertical cross-sectional views showing the steps of an embodiment of a method for constructing a joist slab frame structure using a precast concrete girder according to the present invention, FIG. 3 is a plan view of FIG. 1, and FIG. FIG. 5 is a partial perspective view of the precast concrete girder A, and FIG. 5 is a view showing a part of the floor surface in a plan view showing a state where the semi-precast concrete joist slab has been installed. , FIG. 7 is a longitudinal sectional view of a semi-precast concrete joist slab and a cast-in-place concrete slab, and FIGS. 8 and 9 are a perspective view and a front view showing the end of the joist portion, FIG. 10 and FIG.
Fig. 11 is a longitudinal sectional view and a longitudinal side view showing the state of implementation of the conventional method, respectively. Fig. 10 shows the left half part and the right half part in the arrow ii diagram and the arrow roll diagram of Fig. 11, respectively. is there. A: precast concrete girder, B: semi-precast concrete joist slab, C: precast concrete column or cast-in-place concrete column, R: joist slab, 1 ... hanging recess, 2 ... beam main bar, 3 ... ribs, 31 ... rib hooks, 4 ... joist part, 4a ... semi-precast concrete slab, 5 ... joist end cutout part, 6 ... upper chord member, 7 ... diagonal member, 8 …… Lower chord material, 8a …… End of lower chord material, 9 …… Joint hardware, 10 …… Reinforcing bar 11 …… Main bar of beam, 12 …… Reinforcing concrete slab reinforcing bar, 13 …… In-situ concrete slab .

Claims (4)

[Claims] 1. A one-story precast concrete column height S ₁ except Narudaka of S ₂ of the girder section from S or inter-site punch concrete column C of buildings, RyoNaru height of the girder section
A hanging recess having a beam height S ₃ of a cross section excluding the slab height S ₄₁ of the joist slab R from S ₂ and each end of the joist portion 4 of the semi-precast concrete joist slab B hanging on the beam side surface. The precast concrete joist slab B is constructed by constructing a precast concrete girder A lacking 1 and then forming a semiprecast concrete slab part 4a and a joist part 4 on the lower surface of the slab between the facing girders A. Each end of the portion 4 is fitted and installed in the hanging recess 1 of the girder A, and a beam upper main bar 11 is arranged on the upper surface of the girder A in the beam longitudinal direction. After arranging slab reinforcement bars 12 for reinforcing in-situ cast concrete on the upper surface and the upper surface of the semi-precast concrete joist slab B, the joist portion 4
The construction method of the joist slab using the precast concrete girder characterized by placing the slab concrete 13 on the upper surface of the semi-precast concrete joist slab B and the upper surface of the precast concrete girder A at each end of the . 2. An upper surface of a semi-precast concrete joist slab B at each end portion of the joist part 4 in the semi-precast concrete joist slab B facing each other with a precast concrete girder A having a recess 1 for hanging on the side surface of the girder. A joyce using a precast concrete girder according to claim 1, further comprising: a cutout portion 5 having an open end, and a gate-shaped reinforcing bar 10 is provided between the cutout portions 5 so as to straddle the top of the girder A. Toslab frame construction method. 3. The precast concrete girder A comprises:
Hanging recess 1 for hanging each end of the joist portion of the semi-precast concrete joist slab B on the beam side surface
The joystick using the precast concrete girder according to claim 1, wherein the main beam under the beam and the U-shaped rib 3 are embedded, and the upper end hook portion 31 of the U-shaped rib is projected from the top surface of the beam. Toslab frame construction method. 4. The semi-precast concrete joist slab B has an assembly truss bar arranged in a joist portion,
The upper chord member 6 of the truss reinforcement is embedded so as to project from the upper end surface, and the bent end portions of the lower chord member 8 of the truss reinforcement are anchored in the cutout portions 5 of the respective end portions of the joist portion 4.
The method for constructing a joist slab using a precast concrete girder according to claim 1, which is made to project as 8a.