JP6553161B2 - Large span concrete floor slab formwork and construction method using the floor slab formwork - Google Patents

Description

  The present invention provides, for example, a large-span concrete floor slab form that can be used when constructing a large-span concrete floor slab having a large slab thickness in the upper part of an underground or semi-underground large space, and a large span using the form frame. The present invention relates to a method for constructing a span reinforced concrete slab.

  When building a concrete slab with a large slab thickness of 500 to 1000 mm, for example, in the upper part of the excavated road or underground / underground large space, the formwork is supported by a massive support that can withstand the cast load of concrete. It is common.

  However, it takes a long period of time to set up a large-scale support under the constructed floor slab, and the cost of the support, including the installation work, is enormous, and the floor slab under the support has been installed during construction. Work in space is severely limited.

  In addition, in the large span structure, the inner space is large, and the footings for setting and dismantling of the support work are also large.

  On the other hand, it is conceivable, for example, to construct a large span floor slab without supporting using a steel-concrete composite floor slab having bottom steel plates described in Patent Documents 1 and 2 and the like.

Patent No. 3191569 gazette JP, 2008-144459, A

  As described above, the composite floor slab has the advantage that support work can be omitted and rapid construction is possible. However, in structures where fire resistance is a problem, steel-concrete composite floor slabs in which steel plates are exposed on the lower surface of the floor slab are limited in terms of fire resistance.

  The present invention is intended to solve the above-described problems, and a large-span concrete floor slab form and a floor slab form that enables rapid construction and omission of support work in a structure in which fire resistance is not a problem. The purpose is to provide the construction method used.

The floor form of the present invention is a large span concrete floor form for placing a reinforced concrete floor on a support structure such as a column or a wall, and comprises a form bottom and the form bottom. A plurality of steel rib members having a cross-sectional rigidity sufficient to withstand the load at the time of placing concrete in parallel, the mold bottom plate and the steel rib members are joined and integrated, and made of steel The rib material protrudes from both ends of the formwork bottom plate, and the extra length of the steel rib material protruding from both ends of the formwork bottom plate is supported by the formwork receiving material installed on the support structure . It is characterized in that a plurality of slits on which reinforcing bars to be arranged on a concrete floor plate can be placed are formed in a web of rib material.

  The floor slab to be constructed is a reinforced concrete floor slab having the required cross-sectional synthesis and strength, and concrete reinforcement and reinforcement arrangement design of rebar are made.

  The steel rib members arranged in parallel on the bottom of the formwork only need to have a cross-sectional rigidity sufficient to withstand the load at the time of putting concrete, and in view of securing the cross-sectional rigidity, strip steel plate or shaped steel preferable.

  The material of the mold bottom plate is not particularly limited, but a steel plate is preferable in that the steel rib member can be welded or bolted.

Or you may use a precast-concrete board (following, PCa version) for a formwork bottom plate. Here, the PCa plate is, for example, a reinforced concrete plate, a steel reinforced concrete plate, a prestressed concrete plate, an ultrahigh strength fiber reinforced concrete plate, or the like. When using the PCa version mold bottom plate, it is sufficient to provided beforehand steel ribbing inside PCa plate (Fig. 5 see).

  In this case, the PCa plate can be used as a dumping frame, and the thickness of the PCa plate can be made a load-bearing coating (a part of the fog necessary for securing load-carrying performance).

  Moreover, when using a steel-frame reinforced concrete board for a formwork bottom plate, as shown in FIG. 6, a plurality of holes are provided in the reinforcing steel material and the lower rib material, and the reinforcing bars are installed so as to penetrate the holes. Since the holes provided in the reinforcing steel material and the lower rib member act as a slip stopper, it is possible to integrate the concrete of the mold bottom plate with the steel material.

  When concrete is cast on the main body, the load acts in the direction of pulling out the lower rib from the bottom plate of the mold, but by providing reinforcing steel passing through the reinforcing steel and the lower rib. Thus, it is possible to efficiently resist the pulling load.

  From the viewpoint of securing the cross-sectional rigidity that can withstand the load during concrete placement by the steel rib material, it is also conceivable to provide the steel rib material under the formwork bottom plate, not the floor slab side, In that case, the problem is that the use of space is reduced because the inner empty cross section is violated, and even if it is attempted to overcome this defect by removing the steel rib, the removal is difficult due to height work and is difficult. is there.

  Therefore, in the present invention, in addition to the function of stiffening the formwork to dare to bury steel ribs and to withstand the load at the time of putting concrete, the reinforcing bars arranged in the reinforced concrete floor slab, mainly the lower end bars It has a function of supporting the spacer, and therefore a slit is provided at a position corresponding to the required cover thickness from the lower surface of the reinforced concrete floor slab.

  As described above, the floor slab form of the present invention, including the steel rib material, can be used as it is without removing the mold, but it is not expected to have fire resistance. Reinforcing bars will be secured and designed to meet the fire resistance performance required for reinforced concrete floor slabs.

  In this case, since the reinforcing bars are laid between the slits, it will be difficult to place the slits, especially in the horizontal direction. It is preferable to have a long slot-like slit shape. If it is a long groove-like slit shape, it is possible to insert the reinforcing bars from an oblique state, or to insert a plurality of reinforcing bars together and then move them horizontally so as to obtain an appropriate interval.

  Thus, a reinforced concrete deck slab can be constructed by arranging one or more reinforcing bars arranged in the direction perpendicular to the support span of the concrete deck slab and placing concrete.

  The steel rib members can also be configured by dividing the lower rib members into two upper rib members that can be attached to and detached from the lower rib members via the connecting member.

  In such a case, the lower rib is formed by joining the lower mold and the steel rib in a state where the lower ribs are arranged in parallel on the lower plate of the mold; Ensure that the cross-sectional rigidity is sufficient to support the applied load. That is, even if it is not sufficient to support the load at the time of placing concrete in that state, workers can perform the laying operation on the bottom plate of the formwork, so that the load acting before placing concrete can be supported. Do.

  After that, the reinforcing ribs placed on the concrete floor slab are placed on the upper end of the lower rib member, and the upper rib member is connected to the lower rib member via a connecting member. The cross-sectional rigidity should be sufficient to withstand this load.

  In this case, since the reinforcing bars arranged on the floor slab may be placed on the upper end portion of the lower rib member, the arranging process becomes easier as compared with the case where the reinforcing bars are inserted into the above-mentioned slit.

  The form and connection method of the connecting member are not particularly limited, but if the splice plate and the high strength bolt are used, it is relatively easy to secure the rigidity in the state where the lower rib member and the upper rib member are connected.

  In this way, the upper rib member is installed in an unconnected state, and a plurality of reinforcing bars arranged in the direction perpendicular to the support span of the concrete floor slab are placed on the lower rib member, and the connecting member is used. After the upper rib is connected to the lower rib, concrete can be cast to construct a reinforced concrete floor slab.

  In the case of the synthetic floor slab where the bottom steel plate constitutes a part of the floor slab as a structural member, there is a problem of fire resistance, but in the present invention, a reinforced concrete floor slab structure reinforced by a reinforcing bar having a necessary cover thickness. Therefore, the problem of fire resistance can be cleared.

  By receiving the concrete casting pressure with the cross-sectional rigidity of a plurality of steel rib members arranged in parallel on the bottom plate of the formwork, construction of a large span is possible without requiring extensive support work, particularly rapid construction. It is useful in the required conditions. In addition, since the inner air cross section is not violated by the support work or the like, the work on the inner air cross section can be made parallel.

  By receiving the rebars arranged on the concrete floor slab with the slits formed in the steel rib, the arrangement work is also easy.

  In the case where the steel rib is divided into the lower rib and the upper rib and the upper rib is made detachable by the connecting member, the laying operation is further facilitated.

  When the mold bottom plate is a PCa plate, the mold bottom plate can be used as a mold frame and load-bearing cover (a part of a fog required to ensure load-bearing performance).

  When the PCa version of the formwork bottom plate is a steel reinforced concrete plate, and multiple holes are provided in the reinforcing steel material and lower rib, and reinforcing bars penetrating both holes, the holes provided in the reinforcing steel material and lower rib Acts as a detent and can integrate concrete and steel.

  When placing concrete body, load acts as if the lower rib is pulled out from the bottom plate of the formwork, but by arranging reinforcing bars that penetrate both the reinforcing steel and the lower rib, the efficiency against this pulling out load Can resist.

One Embodiment of this invention is shown, (a) is a top view, (b) is an AA line sectional view of (a), (c) is an BB line sectional view of (a). . (a) is a figure which expanded and showed a part of FIG.1 (b), (b) is an enlarged view of FIG.1 (c). It is the vertical sectional view which showed other embodiment of this invention. (a)-(d) is an expanded sectional view which shows the construction procedure in embodiment of FIG. It is one Embodiment at the time of using a PCa version for a formwork bottom plate in the present invention, and is a schematic perspective view showing a time of laying a panel. FIG. 6 is a schematic perspective view showing the next procedure of the embodiment of FIG. 5 and the time of arranging the bars on the lower side of the floor plate. FIG. 7 shows the next procedure of the embodiment of FIG. 6 and is a schematic perspective view showing the time when the upper rib member is joined. In the present invention, an embodiment in which a steel frame reinforced concrete plate is used as a mold bottom plate is shown. (A) and (b) are cross-sectional views, and (c) is a reinforcing steel material, a reinforcing bar, and a lower rib material. It is a schematic perspective view shown.

  Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

  1 and 2 show an embodiment of the present invention as a floor slab for constructing a large span reinforced concrete floor slab having a thickness of about 50 cm and a span of about 7 m between the support (side wall and central wall) crossing the upper part of the cutting road. It shows a formwork.

  1 (a) is a plan view, FIG. 1 (b) is a sectional view taken along the line A-A, FIG. 1 (c) is a sectional view taken along the line B-B, and FIG. 2 (a) is a part of FIG. FIG. 2 (b) is an enlarged view of FIG. 1 (c).

  The main formwork components are a formwork bottom plate 11 and a steel rib member 12 arranged in parallel on the formwork bottom plate 11, and a large support work between the road side wall 1a and the central wall 1b as a support structure. In a state of being bridged without using, a reinforcement work to be described later is performed, and concrete 7 is placed and cured, whereby a large span reinforced concrete floor slab 2 is constructed on the upper portions of the support structures 1a and 1b. In addition, although the illustration of the road sidewall on the opposite side is omitted, the structure is almost symmetrical.

  In the present embodiment, a plurality of strip-shaped steel plates having a width of 50 cm are connected in the width direction by the connection plate 11a, and the upper surface thereof is a strip-shaped steel plate having a height of 25 cm. The longitudinal direction is made to coincide, and by installing vertically, the section rigidity which withstands the pouring pressure of concrete is secured. The formwork bottom plate 11 and the steel rib member 12 are integrated by bolting or welding in advance.

  In the present embodiment, the mold receiving members 14 are installed on the upper surfaces of the road side wall 1a and the center wall 1b which have already been constructed, and the steel rib members 12 project from the both ends of the mold bottom plate 11 with the mold receiving members 14 The extra length part is supported. In addition, a hunt portion bottom plate 15 is attached to both end portions of the mold bottom plate 11 via a connecting member 16 to form a bottom mold frame of the hunt portion.

  A plurality of slits 13 are formed in the steel rib member 12 at intervals in the longitudinal direction. The slit 13 is formed so that the lower end thereof has a height corresponding to the cover thickness of the lower end streaks 3a and 3b of the floor slab to be constructed, and the lower end streak 3a in the direction orthogonal to the construction span direction is inserted It functions as a spacer for the lower end muscle 3a. If the slit 13 has a slit shape in the form of a long groove, it is easy to insert the lower end muscle 3a and temporarily place it.

  The mold bottom plate 11 does not need to be removed, and becomes a waste form with the steel rib 12, but the fire resistance is not included in the strength, and the constructed floor slab is designed as a reinforced concrete floor slab.

  As a general construction procedure, it is divided into a predetermined width and the formwork bottom plate 11 to which the steel rib member 12 is attached in advance is installed between the road side wall 1a and the center wall 1b without using a large support. In the spanned state, the connecting plate 11a is connected in the width direction with a high strength bolt or the like.

  The construction of the road side wall 1a and the central wall 1b is carried out in such a manner that the extra portion of the steel rib 12 is supported by the mold receiving member 14 as described above, and the hanch bottom plate 15 is set at the hunting position. Moreover, a necessary side mold or the like (not shown) is set for the concrete placement range.

  Next, a plurality of lower end bars 3a in the span orthogonal direction (a direction perpendicular to the longitudinal direction of the steel rib member 12) are inserted into the long groove-like slits 13 of the steel rib member 12, and according to the bar arrangement design. The spacing is adjusted, the lower end reinforcement 3b in the span direction is further placed on the lower end reinforcement 3a, and fixed with a binding wire or the like. Subsequently, work of arranging upper end muscles 4a and 4b is performed using a spacer (not shown).

  In this state, concrete is placed and cured to complete the floor slab. Although the mold bottom plate 11 is left as a disposable mold as it is, the side mold or the like may be either removed from the mold or left as a disposable mold.

  Depending on the width of the slab, the above operation is repeated several times.

  FIG. 3 and FIG. 4 show another embodiment of the present invention, and the object and construction conditions are the same as the embodiment of FIG. 1 and FIG.

  3 is a vertical cross-sectional view, and FIGS. 4A to 4D show the construction procedure corresponding to FIG. 3, with the left-hand side view being an enlarged cross-sectional view seen from the span orthogonal direction and the right-side view being perpendicular thereto. Is an enlarged cross-sectional view in the direction of

  In this embodiment, the steel rib members are divided into a lower rib member 22a and an upper rib member 22b, and these members are joined by a high bolt or the like through a plurality of connection plates 23. .

  By attaching the connection plate 23 to the lower rib 22 a or the upper rib 22 b in advance, the work on the site becomes easy. In that case, the side to be attached in advance may be welded instead of bolted.

  The lower rib member 22a is sufficient to support a load acting before placing concrete, such as an operator performing reinforcement work on the mold bottom plate 11 in a state of being arranged in parallel on the mold bottom plate 11. Ensure that cross-sectional rigidity is ensured.

  Thereafter, lower end reinforcements 3a and 3b arranged on the concrete floor plate 2 are placed on the upper end portion of the lower rib 22a, and the upper rib 22b is connected to the lower rib 22a via the connecting member 23 By doing so, the cross-sectional rigidity which can endure the load at the time of placement of the concrete 7 is ensured.

  In this case, since the lower end streaks 3a and 3b arranged on the floor slab need only be placed on the upper end portion of the lower rib member 22a, as in the embodiment of FIGS. Compared to the case of inserting the bar, the bar arrangement work is easier. Other configurations are the same as those of the embodiment of FIGS.

  As a general construction procedure, it is divided into a predetermined width, and while the form bottom plate 11 to which the lower rib member 22a is attached in advance is installed between the road side wall 1a and the central wall 1b, without using a large support. In the bridged state, the connection plate 11a is connected in the width direction with a high strength bolt or the like (see FIG. 4A).

  Construction on the road side wall 1a and the central wall 1b is performed by supporting the extra length of the lower rib member 22a with the mold receiving member 14, and the haunch bottom plate 15 is set at the haunch position (see FIG. 3).

  Next, the lower end reinforcement 3a in the span orthogonal direction is placed on the upper end portion of the lower rib member 22a, the spacing is adjusted according to the arrangement design, and the lower end reinforcement 3b in the span direction is further arranged on the lower end reinforcement 3a. And fix it with a binding wire (see Fig. 4 (b)).

  After performing the bar arrangement work of the lower end bars 3a and 3b, the upper rib member 22b is connected to the upper side of the lower rib member 22a through the connecting plate 23 by high-strength bolt bonding or the like (see FIG. 4C).

  Subsequently, the upper end bars 4a and 4b are arranged using a spacer (not shown), concrete 7 is placed, and curing is performed to complete a floor plate (see FIG. 4 (d)). .

  Other operations are the same as those in the embodiment of FIGS.

  5 to 8 show another embodiment of the present invention, and the object and construction conditions are the same as those of the embodiment of FIG. 1 and FIG.

  5 to 7 are schematic perspective views in the case of using a hybrid mold in which a PCa plate and a steel rib member 12 are combined in the mold bottom plate 11 of the present invention, and shows the construction procedure. The steel rib members are divided into the lower rib member 22a and the upper rib member 22b, as in FIGS. 3 and 4, and are joined by high bolts or the like via a plurality of connection plates 23. It is

  First, as step 1, FIG. For the mold bottom plate 11, a PCa plate provided with a lower rib member 22a in advance at a factory or the like is used.

  The lower rib member 22a is sufficient to support a load acting before placing concrete, such as an operator performing reinforcement work on the mold bottom plate 11 in a state of being arranged in parallel on the mold bottom plate 11. Ensure that cross-sectional rigidity is ensured.

  By attaching the connecting plate 23 to the lower rib member 22a in advance, field work is facilitated. In that case, the side to be attached in advance may be welded instead of bolted.

  Next, as Step 2, FIG. 6 shows the bar arrangement below the floor slab. The lower end reinforcements 3a and 3b arranged on the concrete floor plate 2 are placed on the upper end of the lower rib 22a, and the lower rib 22a is used as a spacer.

  As Step 3, FIG. 7 shows joining of the upper rib member 22b. The upper rib member 22 b is connected to the lower rib member 22 a via the connecting member 23 to secure a cross-sectional rigidity that can withstand the load at the time of placing the concrete 7.

  In this case, since the lower end streaks 3a and 3b arranged on the floor slab need only be placed on the upper end portion of the lower rib member 22a, as in the embodiment of FIGS. Compared to the case of inserting the bar, the bar arrangement work is easier.

  In addition, the PCa plate can be used as a dumping frame, and the thickness of the PCa plate can be made a load-bearing coating (a part of the fog required to ensure load-bearing performance).

  Other configurations and other operations are the same as those in the embodiment of FIGS.

  Fig. 8 shows a case where a reinforced concrete steel plate provided with a channel steel as a reinforcing steel material is used for the PCa version of the mold bottom plate 11 of the present invention, and Figs. 8 (a) and 8 (b) are sectional views. FIG. 8C is a perspective view.

  As shown in FIGS. 8 (a) to 8 (c), a plurality of holes are respectively provided in the channel steel 31 and the lower rib 22a, and the holes of the channel steel 31 and the lower rib 22a are penetrated. Reinforcing bars are provided to form a PCa plate.

  The holes provided in the channel steel 31 and the lower rib member 22 act as a slip stopper, and the concrete of the bottom plate of the formwork and the steel material can be integrated.

  The operation after joining the connection plate 23 to the lower rib member 22a with a high bolt or the like and the other configuration are the same as those of the embodiment of FIGS.

  When using a steel-frame reinforced concrete board as the formwork bottom plate 11, when placing concrete in the main body, a load acts in a direction in which the lower rib member 22a is pulled out from the formwork bottom plate 11. However, by providing the reinforcing bars penetrating the reinforcing steel material 31 and the lower rib member 22a, it is possible to efficiently resist this pulling out load.

  While an example in which the channel steel 31 is installed outward in FIG. 8A and inward in FIG. 8B is shown, both are effective.

  Here, an example using a channel steel as a reinforcing steel material is shown, but it is not particularly limited as long as a plurality of holes can be provided in the H-shaped steel and other reinforcing steel materials and there is no problem in terms of strength.

DESCRIPTION OF SYMBOLS 1a ... Side wall (support structure), 1b ... Center wall (support structure), 2 ... Large span reinforced concrete floor slab, 3a, 3b ... Lower end reinforcement, 4a, 4b ... Upper end reinforcement, 5 ... Wall main reinforcement, 6 ... Shear reinforcement Muscle, 7 ... concrete,
DESCRIPTION OF SYMBOLS 11 ... Bottom plate, 11a ... Connection plate, 12 ... Rib material, 13 ... Slit, 14 ... Formwork receiving material, 15 ... Haunch part bottom plate, 16 ... Connection material,
22a ... lower rib material, 22b ... upper rib material, 23 ... connecting plate,
31 ... Reinforcement steel (channel steel), 32 ... Rebar

Claims (4)

A large-span concrete floor slab form for placing reinforced concrete floor slabs on a support structure, which is paralleled on the formwork bottom plate and the formwork bottom plate and is only able to withstand the load during concrete placement. A plurality of steel rib members having a cross-sectional rigidity, wherein the mold base plate and the steel rib member are joined and integrated, and the steel rib members protrude from both ends of the mold base plate The extra length portion of the steel rib member protruding from both ends of the mold bottom plate is supported by a mold receiving member installed on the support structure, and the steel rib member includes the concrete floor slab. long span concrete slab formwork you characterized by rebar be placed slit to be Haisuji is formed with a plurality. Long span concrete slab formwork according to claim 1, wherein said steel rib material which is a steel strip or shape steel. The large-span concrete floor slab form according to claim 1 or 2, wherein the slit is a long groove-like slit long in the longitudinal direction of the steel rib material. A large span concrete floor slab form according to claim 1, 2 or 3 is installed between support spans by the support structure, and reinforcing bars arranged in the direction perpendicular to the support span of the concrete floor slab are disposed in the respective slits. A method for constructing a reinforced concrete slab using a large-span concrete slab formwork, wherein one or a plurality of slabs are placed and concrete is placed.