JP2004060340A - Full precast hollow floor slab and integral structure of the floor slab and building frame beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precast hollow floor slab which is a hollow floor slab (which is appropriate for an extra long span) improved in thinning of plate, lightening of weight, and workability. <P>SOLUTION: A beam section 2 and a hollow section 3 are integrally formed on the upper part of a lower layer concrete 5 forming the lower external shape of a precast hollow floor slab 1. An upper layer concrete 6 is integrally formed on the beam section 2 and hollow section 3, and the beam section 2 and the hollow section 3 are unevenly exposed over a specified range at the longitudinal both ends of the hollow floor slab 1. A PC steel member 4 extendedly arranged in the longitudinal direction of the floor slab is disposed in the beam section 2. Vertical and lateral reinforcements are arranged in the upper layer concrete 6, and joint reinforcements 12a, 13a are projected by a specified length from the ends and the sides of the concrete 6. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates mainly to a full precast hollow slab capable of reducing the weight of a slab (or suitable for a long span), an integrated structure of the hollow slab and a skeleton beam, and a method of constructing the same. .
[0002]
[Prior art]
Buildings are constructed by assembling structural members such as floors, ceilings, and roofs into columns and beams, and structural members with different lengths are required, especially for long spans of about 10 m and standard spans of about 6 to 7 m. For example, a floor slab, which is one of the structural members, is required to have a particularly lightweight and high-strength member, and precasting of the floor slab is proceeding as a means to meet this demand.
[0003]
The conditions required for a floor slab of a building will be described in more detail in the following four points. (1) Reducing the weight of the floor slab and improving the strength leads to a reduction in the thickness of the floor slab and a reduction in the amount of concrete used. (2) By reducing protrusions such as beams and ribs on the lower surface of the floor slab, the ceiling can be set a little higher in the limited height gap between the upper and lower floors, and the space for air conditioning ducts etc. is secured. . (3) We want to increase the number of floor slabs manufactured at the factory, reduce the number of site construction parts as much as possible, and improve the workability.
[0004]
The characteristics of the floor slabs that meet the requirements of (1) to (3) above are the slabs that are lightweight, rich in strength, and require less on-site construction. Currently, the closest slabs that can meet this requirement are: This is a so-called half precast slab, and a two-way hollow slab disclosed in JP-A-7-197575 is a prior example.
[0005]
Japanese Patent Application Laid-Open No. 7-197575 is obtained by synthesizing upper and lower precast plates in which main reinforcing bars are embedded in two directions, and has voids (hollow portions) arranged in two directions at joints. At the time of its production, an upper precast plate with a large number of recesses formed on the back side is first manufactured, and this is overlaid on the lower precast plate in an uncured state and pressurized, into the concrete of the upper precast plate The concrete is pressed slightly, and the concrete of the lower precast plate is hardened in this state.
[0006]
The above-mentioned conventional example is a slab in which the weight is reduced by having a void (hollow portion), but this slab involves concrete casting of a lower precast plate construction on site. However, there is a reality that the higher the height of the building, the more concrete and concrete placing on the site becomes burdensome in terms of process and cost. Further, it is environmentally unfavorable that an increase in the loading of ready-mixed concrete vehicles to the construction site increases. Further, in the conventional void slab, the maximum possible column span from the strength aspect is 7 to 8 m, and there is a limit in this point as well. In addition, when introducing prestress into this conventional void slab, a tension member is put into the lower precast plate at the site work, and the tension is released after the concrete hardens, so the site work further increases, especially on the upper floor of the building. This is not preferable as the operation to be performed.
[0007]
JP-A-11-107424 is disclosed as another conventional technique. This conventional example is a floor slab in which precast reinforcing bars are arranged in a state in which tension is applied to concrete to reduce weight by forming hollow portions (voids), but is a half precast plate itself. In the field work, complicated arrangements were made between reinforcing bars pre-arranged on the existing structural skeleton, and then concrete of predetermined thickness was cast on the upper surface of the half precast slab to complete the construction of the floor slab That is the current situation.
[0008]
[Problems to be solved by the invention]
The conventional half-precast slabs are simply placed on the structural skeleton as floor slabs and ceiling panels, and the construction is not completed.Concrete placement work on the site and complicated arrangement work of reinforcing bars with the skeleton beams are required Therefore, there is a problem that the workability is poor.
[0009]
In addition, when casting concrete on the upper part of the half precast plate by cast-in-place, it is necessary to provide support at both ends of the half precast plate and several intermediate points when erection, and distribute it on the entire upper surface of the precast plate. There is a lot of work on site where the concrete is poured and the work is done, which lacks workability and safety. Further, the half precast plate becomes thicker and heavier due to the more concrete poured. Thus, slabs constructed using conventional half-precast plates are thinner, lighter, easier to construct, reduce construction costs including labor costs, and furthermore, the difficulty of supplying ready-mixed concrete on the upper floors of the building, There was room for improvement in affecting the surrounding environment and shortening the construction period.
[0010]
The present invention has been made in view of the drawbacks of the conventional half precast plate, and has been improved in terms of reducing the thickness and weight of the precast plate, ease of construction and accompanying concrete reduction, cost reduction, etc. The purpose is to provide floor slabs.
[0011]
[Means for Solving the Problems]
In order to solve the above problem, the present invention is configured as follows.
[0012]
The full precast hollow slab of the first invention comprises a slab body in which beam portions and hollow portions extending in the longitudinal direction of the slab are alternately arranged in the width direction of the slab to form a slab main body. It is characterized in that a PC steel material is arranged by extending in the longitudinal direction, a reinforcing bar is arranged on a solid portion of the floor slab, and an end of the reinforcing bar is projected from the end of the floor slab as a joint reinforcing bar by a predetermined length. I do.
[0013]
According to a second aspect of the present invention, in the first aspect, a lower layer concrete serving as a lower outer shape of the floor slab, the beam portion and the hollow portion integrally formed on the upper portion of the lower layer concrete, and the beam portion and the hollow portion It is made of upper layer concrete which is the upper outline of the floor slab integrally formed on the upper part of the floor slab. At the longitudinal end of the hollow slab, the beam and the hollow are exposed in a convex and concave shape over a predetermined range. It is characterized by having.
[0014]
A third invention is characterized in that the bottom of the hollow portion located on the side of the floor slab is exposed on both sides in the longitudinal direction of the full precast hollow slab of the second invention.
[0015]
According to a fourth aspect of the present invention, there is provided a hollow slab according to the third aspect of the present invention, wherein both longitudinal ends of the hollow slab are erected between a frame beam having a predetermined span, and a joint reinforcing bar projecting from the floor slab and a joint part projecting from the beam side. Reinforcement is joined above the part where the beam and the hollow part of the floor slab are exposed in an uneven manner, and the joint rebar protruding from the adjacent slab is connected to the hollow part on both sides in the longitudinal direction of the floor slab. The joint is assembled above the exposed bottom portion, and the joint concrete is cast so as to bury the joint of the joint rebar.
[0016]
According to a fifth aspect of the present invention, there is provided an integrated construction method of a full precast hollow floor slab and a skeleton, wherein the hollow slab according to the second invention is erected on a skeleton beam having a predetermined span, and a joint reinforcing bar and a hollow floor projecting from the skeleton beam. The joint rebar protruding from the side of the slab is combined with the beam at both ends in the longitudinal direction of the floor slab and above the unevenly exposed portion of the hollow portion, and above the bottom exposed portion of the hollow portion on both sides in the longitudinal direction of the slab. In this method, joint reinforcing bars protruding from adjacent floor slabs are combined, and joint concrete is cast at both end portions and both side portions of the floor slab so that the joint reinforcing bars are embedded.
[0017]
[Action]
In the present invention, since the full precast hollow slab is formed by combining the concrete whose weight is reduced by forming the hollow portion (void) and the PC steel material to be arranged in the beam portion 7, the hollow slab can be reduced in thickness. In addition, since it has high strength, it is possible to achieve a reduction in weight and a reduction in concrete, thereby making it possible to ensure a long span between columns and secure a ceiling space.
[0018]
In addition, the factory-manufactured full precast hollow slab was transported to the site, erected on an existing skeleton beam of a predetermined span, and a joint reinforcing bar projecting from the hollow slab side and a joint reinforcing bar projecting from the skeleton beam were arranged. In addition, since a flat floor slab is constructed by casting concrete at the joints at the joints, it is easy to join the rebars at the joints and the concrete casting work on site is reduced to the minimum necessary. The workability can be greatly improved compared with the conventional case.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
FIG. 1 is a cutaway plan view of a single unit of a full precast hollow slab according to the present embodiment (hereinafter, may be abbreviated as a hollow slab), and FIG. 2 joins two adjacent hollow slabs in a frame beam. FIG. 3 is a plan view of a state after the hollow slabs have been joined together, similarly to a broken plan view of the previous state.
[0021]
FIG. 4A is a cross-sectional explanatory view of a state before the full precast hollow slab is placed on the skeleton beam, and FIG. 4B is a cross-sectional view of a reinforcing bar that engages the hollow slab with the skeleton beam and protrudes from both members. FIG. 5 (a) is a sectional explanatory view showing a state after the hollow floor slab has been placed on the skeleton beam, and FIG. 5 (b) is a cross-sectional explanatory view of the state after the hollow slab has been mounted on the skeleton beam. FIGS. 6 (a) and 6 (b) are partially enlarged sectional views of a state in which concrete at the connecting portion is laid so that reinforcing bars protruding from both members are buried, and FIGS. FIG. 7 is an enlarged detailed view of a portion C in FIG.
[0022]
As shown in each figure, the full precast hollow slab 1 according to the present invention has a floor 2 in which beam portions 2 and hollow portions (voids) 3 extending in the longitudinal direction of the slab are alternately arranged in the width direction of the slab. The plate main body 1a is formed, and a PC steel material 4 made of, for example, a piano wire is disposed in the beam portion 2 in the longitudinal direction of the floor slab, and longitudinal and horizontal reinforcing bars are arranged above and below the solid portion of the floor slab. Then, an end of the upper reinforcing bar is formed as a joint reinforcing bar by protruding a predetermined length from an end of the floor slab. (The details will be described later.) The beam 2 is a concept corresponding to the hollow 3 and is a solid portion filled with concrete, and is a portion that receives bending moment and shear acting on the floor slab. Means
[0023]
More specifically, the hollow slab main body 1a includes a lower layer concrete 5 serving as a lower outer shape of the floor slab, the beam portion 2 and the hollow portion 3 integrally formed on the upper portion of the lower layer concrete 5, a beam portion 2 and An upper layer concrete 6 is formed integrally with the upper portion of the hollow portion 3 and serves as an outer shape of the floor slab.
[0024]
In addition, by positioning the edge step 6a of the upper layer concrete 6 near the center from the floor edge 7 at both ends in the longitudinal direction of the floor slab main body 1a, the edge step 6a is accordingly extended over a predetermined range. The beam portion 2 and the hollow portion 3 are exposed in an uneven manner.
[0025]
Furthermore, by positioning the side edge steps 6b of the upper layer concrete 6 near the center from the slab side edges 8 on both sides in the longitudinal direction of the slab main body 1a, the hollow portions 3a located on both sides of the slab are formed. The bottom is exposed.
[0026]
In the full precast hollow slab 1, a PC steel material 4 such as a piano wire is buried in the lower part of the beam portion 2, that is, at a portion near the boundary with the lower layer concrete 5, in the longitudinal direction of the slab. As a means for embedding the PC steel material 4, when the floor slab body is manufactured at the factory, the PC steel material 4 is placed in a tensioned position at the position where the beam part 2 is to be constructed, and concrete is poured. A fixing portion is provided at the position of the end portion 10 and an extra length portion is cut and manufactured. In FIG. 6 and FIG. 7, three PC steel members 4 are arranged for each beam portion 2. However, the number of PC steel members 4 may be increased or decreased according to the required prestress. It may be arranged in several steps or the strength of PC steel per one may be changed.
[0027]
The hollow portion 3 contributes to the weight reduction of the hollow slab 1, and the beam portion 2 filled with concrete fulfills a beam function against a compressive force acting in the longitudinal direction of the hollow slab 1. In addition, in order to form the hollow portion 3, a tubular mold may be used, or a long hard foamed resin may be used, and the forming means of the hollow portion 3 is optional.
[0028]
In addition, by arranging the PC steel material 4 such as a piano wire in the beam portion 2, the strength of the beam portion 2 can be further improved, and the strength reduction of the floor slab due to the formation of the hollow portion 3 can be reinforced. As a result, the hollow slab 1 can achieve a reduction in thickness and weight, a reduction in the amount of concrete material, and an intended purpose of improving strength.
[0029]
In the hollow slab 1, an upper vertical bar 12 extending in the longitudinal direction of the slab and an upper horizontal bar 13 extending in the width direction are arranged in a portion not intersecting with the PC steel material 11, that is, a thick portion of the upper layer concrete 6. It is. Both ends of the upper vertical bar 12 project from the edge step 6a of the upper layer concrete 6 to become a joint reinforcing bar 12a, and are located above the uneven portion 11 where the ends of the beam portion 2 and the hollow portion 3 are exposed. ing. Both ends of the upper horizontal bar 13 project from the side edge step 6b of the upper layer concrete 6 to form a joint reinforcing bar 13a, and are located above the exposed portions 14 of the hollow bottoms on both sides of the floor slab.
[0030]
As shown in FIG. 7, a lower vertical bar 15 extending in the longitudinal direction of the floor slab and a lower horizontal bar 16 extending in the width direction are also provided in the thick portion of the lower concrete layer 5. The ends of the lower vertical bar 15 and the lower horizontal bar 16 extend to the end surface of the lower concrete 5. Further, a rectangular abdominal muscle 24 is provided so as to connect the upper vertical bar 12 and the lower vertical bar 15 across the lower concrete layer 5, the beam 2 and the upper concrete layer 6.
[0031]
The factory production of the hollow slab 1 according to the present embodiment is performed in the following steps (1) to (10). (1) Set the mold bottom plate and the mold side plate.
(2) The lower vertical reinforcing bar 15 and the lower horizontal reinforcing bar 16 of the hollow slab 1 are arranged in the formwork.
{Circle around (3)} Place the PC steel material 4 and lightly tension it.
(4) An abdominal muscle (stab wrap) 14 is arranged in a portion to be the beam 2 of the floor slab.
{Circle over (5)} The lower layer concrete 5 is poured to the lower end where the hollow portion (void) 3 is to be formed, and the surface is smoothed.
[0032]
{Circle around (6)} A member for forming the hollow portion 3 is arranged (however, the means for forming the hollow portion is not limited), and a device for preventing the hollow portion 3 from rising on the lower concrete 5 previously cast so as not to float. Is embedded.
(7) The upper vertical reinforcing bar 12 and the upper horizontal reinforcing bar 13 of the hollow slab 1 are arranged.
{Circle around (8)} The bottom of the hollow portion 3 and the upper surface of the beam portion 2 are unevenly exposed at both ends in the longitudinal direction of the hollow slab 1 and are located on both sides of the hollow slab 1 on both sides of the slab. An upper layer concrete 6 is cast so as to expose the bottom of the hollow portion 3a to be exposed, and the surface is pressed with a trowel, followed by steam curing.
[0033]
(9) The cast concrete is cured, and on the next day, it is confirmed that the concrete has a predetermined strength. The PC steel material 4 is cut and precast is introduced into the floor slab.
[10] Remove the floor slab and move to the stockyard.
[0034]
The hollow slab 1 manufactured in the above-mentioned process is constructed as a slab or a ceiling slab by bridging the frame 17. The skeleton beam 17 includes a beam main body 17a and a jaw portion 17b. A beam-side joint portion reinforcing bar 19 having a predetermined length is implanted on a side surface of the beam main body 17a by an insert 18 so as to protrude in a lateral direction.
[0035]
Next, the steps of erection and integration of the hollow slab 1 on the frame beam 17 and the step of joining the hollow slabs 1 to each other will be described with reference to FIGS.
[0036]
(1) Supports 20 are previously installed at both ends of the hollow slab 1 to be engaged with the skeleton beam 17. (2) The hollow floor slab 1 is carried to a predetermined position by a lifting machine (not shown), and both ends 11 in the longitudinal direction of the hollow floor slab 1 are attached to the jaws 17 a of the frame beam 17 as shown in FIGS. 4 and 5. install. (3) Adjust the height of the support 20 to match the level of the hollow slab 1.
[0037]
(4) As shown in FIG. 4, on the upper surface side of both ends 11 in the longitudinal direction of the hollow floor slab 1, the joint reinforcing bar 12 a projecting from the edge step 6 a of the upper layer concrete 6 and projecting from the skeleton beam 17 side. At the same time as joining the rebar 19 at the beam side joint, a hollow part forming member such as a formwork or a hard foam resin is arranged so that concrete does not go around the part where the hollow part 3 is to be formed. Pour concrete 21 up to the level.
[0038]
(5) At the time of joining adjacent hollow slabs 1, both side edges 8 of both hollow slabs 1 where the bottom of the hollow portion 3 a is located abut against each other and protrude from the side edge step 6 b of the upper concrete 6. A hollow part forming member such as a formwork or a hard foam resin is arranged so that the concrete parts do not enter the part where the hollow part 3 is to be formed, together with the joint rebars 13a that are connected to each other. The concrete section 21 is cast to the same level.
(6) After confirming the strength of the concrete 21 at the connecting portions cast at both ends and both sides of the floor slab 1, the support 20 is removed and the construction is completed.
[0039]
Since the full precast hollow slab 1 of the present invention is lightweight and strong, it can be smoothly installed between the frame beams 17 having a long span such as a 10 m span. Moreover, the connection part concrete 21 is firmly joined by the connection part concrete 21 between the hollow floor slab 1 and the skeleton beam 17 and between the hollow floor slabs 1 through the joint part reinforcing bars 12a and 13a.
[0040]
According to the embodiment of the present invention, since the precast plate is fully precast at the manufacturing stage, the strength of the floor slab is increased, the thickness of the slab can be reduced and the weight can be reduced, and the span of the support member is 6 to 7 m. As a result, it is possible to make the span as large as 10 m. Also, when installing the floor slab, it can be temporarily supported only by the supports at both ends and there is no need for support in the middle, so a large space with good workability can be obtained, and removal of the support after striking on the site is easy and leads to safe work . In addition, by minimizing on-site reinforcement and concrete placement work, the number of vehicles entering the construction site was reduced, improving the surrounding environment and shortening the construction period.
[0041]
Furthermore, since the adjacent hollow slabs 1 are reinforced with each other and integrated with cast-in-place concrete, no step is formed at the end of the slab, and the entire slab is flat and the ceiling slab 1 Since there is no protrusion such as beams or reinforcing ribs on the lower surface and the back surface can be flat, the space required for the air conditioning duct can be freely secured in the ceiling space.
[0042]
【The invention's effect】
According to the full precast hollow floor slab according to the present invention, a full precast hollow floor slab is formed by combining a concrete and a PC steel material which have been reduced in weight by forming a hollow portion (void). This makes it possible to reduce the thickness of the slab and enhance the strength, achieve the reduction in the weight of the floor slab, and the reduction in the concrete, thereby ensuring a large span between the pillars and securing the space in the ceiling.
[0043]
In addition, the factory-manufactured full precast hollow slab is transported to the site, installed on an existing skeleton beam of a predetermined span, and the joint reinforcing bar projecting from the hollow slab and the joint reinforcing bar projecting from the skeleton beam are combined. Since a flat floor slab is constructed by casting concrete at the joints at the joints, it is easy to join the reinforcing bars at the joints, and it is possible to reduce the concrete casting work at the site and to improve the workability. Compared with this, the cost can be greatly improved and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a cutaway plan view of a single unit of a full precast hollow slab (hereinafter referred to as a hollow slab) according to an embodiment of the present invention.
FIG. 2 is a cutaway plan view before joining two hollow slabs installed on a skeleton beam.
FIG. 3 is a plan view after joining the hollow floor slabs.
FIG. 4 (a) is a cross-sectional explanatory view before a full precast hollow slab is placed on a skeleton beam, and FIG. 4 (b) shows a reinforcing bar that engages the hollow slab with the skeleton beam and projects from both members. It is the partially expanded sectional view which was combined.
FIG. 5 (a) is a cross-sectional explanatory view after the hollow floor slab has been placed on the skeleton beam, and FIG. 5 (b) is a steel bar in which the hollow slab is engaged with the skeleton beam and protrudes from both members. FIG. 5 is a partially enlarged cross-sectional view in which concrete of a connecting portion is cast in such a manner.
FIGS. 6A and 6B are a cross-sectional view taken along line AA and a cross-sectional view taken along line BB of FIG. 3, respectively.
FIG. 7 is an enlarged detailed view of a portion C in FIG. 6 (a).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hollow slab 1a Floor slab main body 2 Beam part 3 Hollow part 4 PC steel material 5 Lower layer concrete 6 Upper layer concrete 7 Floor slab edge 8 Floor slab side edge 10 Beam end 11 Floor slab longitudinal both ends 12 Top vertical Bar 13 Upper horizontal bar 14 Exposed portion 15 Lower vertical bar 16 Lower horizontal bar 17 Body beam 18 Insert 19 Beam side joint rebar 20 Support 21 Connection concrete 24 Abdominal muscle

Claims (5)

A beam portion extending in the longitudinal direction of the floor slab and a hollow portion are alternately arranged in the width direction of the floor slab to constitute a floor slab body, and a PC steel material is arranged on the beam portion in the longitudinal direction of the floor slab to extend. A full precast hollow slab in which a reinforcing bar is arranged on a solid portion of the slab, and an end of the reinforcing bar is used as a joint reinforcing bar and protrudes from the end of the slab by a predetermined length. 2. The full precast hollow floor slab according to claim 1, wherein the lower layer concrete is a lower outer shape of the floor slab, the beam portion and the hollow portion integrally formed on the upper portion of the lower layer concrete, and the beam portion and the hollow portion. The upper slab is integrally formed on the upper part of the upper slab, and the upper slab is made of concrete. At the longitudinal end of the hollow slab, the beam and the hollow are exposed in a convex and concave shape over a predetermined range. A fully precast hollow floor slab characterized by: 3. The full precast hollow slab according to claim 2, wherein the bottom of the hollow portion located on the side of the slab is exposed on both sides in the longitudinal direction of the full precast hollow slab. The longitudinal slab of claim 3 is erected between frame beams having a predetermined span, and a joint reinforcing bar projecting from the floor slab and a joint reinforcing bar projecting from the beam side are connected to the beam of the floor slab. And the hollow portion are arranged above the portion where the hollow portion is exposed in an uneven manner, and the joint rebars protruding from the adjacent floor slabs are connected to each other above the bottom portions of the hollow portions on both sides in the longitudinal direction of the floor slab. An integrated structure of a full precast hollow slab and a frame beam, wherein a connecting part concrete is cast so as to bury a joint part of the joint part reinforcing bar. The hollow slab according to claim 2 is erected on a skeleton beam having a predetermined span, and a joint reinforcing bar projecting from the skeleton beam and a joint reinforcing bar projecting from the side of the hollow slab are beams at both ends in the longitudinal direction of the floor slab. Attached above the exposed portion of the hollow portion on both sides in the longitudinal direction of the floor slab together with the joint rebar projecting from the adjacent floor slab above the exposed bottom of the hollow portion on both sides in the longitudinal direction of the floor slab, An integrated construction method of a full-precast hollow slab and a skeleton beam, wherein concrete joints are cast on both sides so that both joints are buried.

Images