JP5047060B2 - Synthetic floor slab and its reinforcement method - Google Patents

Description

  The present invention relates to a composite floor slab using a cold-bending material and a reinforcing method thereof.

Steel slab slabs can be broadly classified into reinforced concrete slabs (RC slabs), prestressed concrete slabs (PC slabs), and synthetic slabs. Among these, the synthetic floor slab is a floor slab made of steel and concrete, in which a steel plate panel is laid on a steel girder, and then concrete is driven in to synthesize the steel plate panel and the concrete so as to be integrated.
Such composite floor slabs have higher load resistance than conventional reinforced concrete slabs, so long floor slab spans can be constructed with thin floor slab thickness, formwork and support can be omitted, and there is a bottom steel plate to provide concrete. There is a feature that there is no danger of falling of a piece.

FIG. 7 is a schematic cross-sectional view of a synthetic floor slab. As shown in this figure, a composite floor slab 51 is obtained by arranging a main reinforcing bar 55 on an upper part of a steel plate panel 54 composed of a bottom steel plate 52 and a reinforcing material 53 attached thereto, and further driving a concrete 56 into an integrated unit. It is.
The thickness of the composite floor slab 51, that is, the height from the lower surface of the bottom steel plate 52 to the upper surface of the concrete 56 is referred to as “floor slab thickness”.

  As the above-mentioned synthetic floor slab, those having various structures have been conventionally proposed (for example, Patent Documents 1 and 2).

The “steel bottom formwork and floor slab” of Patent Document 1 improves durability, lowers construction costs, shortens the construction period, and further facilitates construction while ensuring the strength and durability of the joints. The purpose is to.
Therefore, as shown in FIG. 8, the composite floor slab 60 includes a steel bottom mold 61, a loop reinforcing bar 65 arranged on the rib, and a concrete C placed on the steel bottom mold 61. It has. Further, the steel bottom mold 61 includes a bottom steel plate 62 and a U-shaped rib 63 fixed to the bottom steel plate 62 so as to have a substantially inverted U shape.

The “steel skeleton structure of a steel-concrete composite floor slab” in Patent Document 2 aims at a structure that can stand on its own without being deformed on a girder even when casting concrete and has good workability.
Therefore, as shown in FIG. 9, the steel skeleton 71 forming the floor slab 70 integrated with the concrete layer and strength-synthesized has a joint reinforcing beam 73 fixed to the upper surface of the bottom steel plate 72 forming the lower surface, The upper surface of the haunch portion 74 of the bottom steel plate 72 and the coupling reinforcing beam 73 are coupled by a support plate 75 so that the entire weight can be supported by the haunch portion 74.

JP-A-11-192613, “Steel bottom formwork and floor slab” Japanese Patent Application Laid-Open No. 2004-19386, “Steel framework structure of steel concrete composite slab”

  The steel plate panel described above needs to support its weight when placing concrete, and after completion as a composite floor slab, it is necessary to support a vehicle or the like passing through the upper part. Therefore, the composite floor slab and the steel plate panel need to have a sufficiently high bending rigidity (also referred to as “rigidity”) at a predetermined floor slab thickness.

  The above-described main reinforcing bars (also referred to as “truss reinforcing bars”) are mainly used for the purpose of receiving a tensile force acting on concrete.

  In addition, in order to increase the bending rigidity of the steel plate panel, the above-described reinforcing material (also referred to as “rib material”) is fixed to the upper surface of the bottom steel plate by welding or the like at intervals. Furthermore, the entire steel plate panel welded with the reinforcing material also increases the rigidity of the composite slab.

  Conventionally, U-shaped ribs of Patent Document 1 and reinforcing beams of Patent Document 2 have been used as reinforcing materials for bottom steel plates. The U-shaped rib is an inverted U-shaped steel plate, and the reinforcing beam is a channel material or other type steel.

However, the conventional synthetic floor slab has the following problems.
(1) Since the bottom steel plate and main reinforcing bars have a small section modulus, they do not contribute much to the bending rigidity of the composite slab. Therefore, when the bending rigidity of the reinforcing material is low, a large number of reinforcing materials are required, resulting in an increase in cost.
(2) Shape steel (for example, channel material) has a large section modulus, but has high processing costs such as cutting and drilling.
(3) Since the specified size of the shape steel is fixed, it may not be possible to select the optimal dimensions in terms of design. For example, when the strength is slightly insufficient, it is necessary to increase the size by one, which may be disadvantageous economically.
(4) In the case of lightweight steel, the flange portion is bent at a right angle, and there is a possibility that a void may be formed on the lower surface of the flange portion after placing concrete.
(5) Since the coating process, which is a process performed for rust prevention after processing, is a separate process from the processing process, the coating cost increases.

  The present invention has been developed to solve the above-described conventional problems. In other words, an object of the present invention is to obtain a desired bending rigidity with a predetermined thickness (height) with a small amount of reinforcing material, and to easily set an optimum dimension in design. It is an object of the present invention to provide a synthetic floor slab and a method for reinforcing the same, which are difficult to form and can reduce the processing cost of cutting, drilling and painting.

According to the present invention, a flat bottom steel plate extending horizontally;
A composite floor slab having a plurality of reinforcing materials welded to the upper surface of the bottom steel plate in parallel with each other at intervals,
The reinforcing member is a rectangular steel plate bent along the length direction, and a web extending perpendicularly to the bottom steel plate from a leg welded to the bottom steel plate, and a predetermined upward direction with respect to the horizontal from the upper end of the web. the length of the bent one width direction to have a a long inclined flange than the length in the width direction of the legs at an angle, synthetic floor plate is provided, characterized in that.

  According to a preferred embodiment of the present invention, the leg portion of the reinforcing member is a horizontal portion bent horizontally toward the inclined flange side at the lower end surface of the web or the lower end of the web.

  The inclined flange is made of one or two folded steel plates whose width is set to obtain a predetermined bending rigidity.

Further, according to the present invention, a web made of a rectangular steel plate bent along the length direction and extending perpendicularly to the bottom steel plate from a leg welded to the bottom steel plate, and a predetermined horizontal position from the upper end of the web. A plurality of reinforcing members each having an inclined flange that is bent to one side at an upward angle and whose length in the width direction is longer than the length in the width direction of the leg portion are parallel to each other on the upper surface of a horizontally extending plate-shaped bottom steel plate There is provided a method for reinforcing a composite slab characterized by welding at intervals.

According to a preferred embodiment of the present invention, the web is provided with a concrete hole through which fresh concrete can be passed before bending, and the inclined flange has an air hole through which fresh air can pass through before being bent. Is provided.
The concrete hole is preferably a circular hole, an elliptical hole, or a rectangular hole having a protrusion bent at an end.

  According to the configuration of the present invention, since the reinforcing material is made of a rectangular steel plate bent along the length direction, the height of the reinforcing material, the width of the inclined flange, and its Since the inclination angle can be set freely, it is possible to obtain a desired bending rigidity with a predetermined thickness (height) and a small amount of reinforcing material, and it is possible to easily set an optimum dimension in design.

  Further, since the inclined flange is bent at a predetermined upward angle with respect to the horizontal at the upper end of the web, it is difficult to form a concrete gap on the lower surface of the flange portion.

  Furthermore, since the concrete hole and the air hole are processed before the bending in the processing step, the material (rectangular steel plate) can be cut, bent, and drilled in the same step, so that the processing cost can be reduced.

  In addition, bending using a press allows continuous processing in the longitudinal direction, and the painting process (blasting, painting) can be performed continuously in the longitudinal direction, which can be automated by a machine, further reducing costs. Can be lowered.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 1 is a diagram showing a first embodiment of a synthetic floor slab according to the present invention. In this figure, (A) is a cross-sectional view subjected to bending, and (B) is an arrow view taken along the line BB.
In this figure, the composite floor slab 10 of the present invention has a flat bottom steel plate 12 extending horizontally and a plurality (three in this figure) of reinforcing members 20. The plurality of reinforcing members 20 are welded to the upper surface of the bottom steel plate 12 at intervals in parallel to each other, and constitute an integrated steel plate panel 14 as a whole.

  The composite floor slab 10 of the present invention further includes a main rebar 16 positioned substantially horizontally above the steel plate panel 14 and a concrete 18 embedded with the steel plate panel 14 and the main rebar 16 embedded therein.

FIG. 2 is a detailed view of the steel plate panel 14 of FIG. In this figure, (A) is an enlarged view of part A of FIG. 1 (A), and (B) is a perspective view of a steel plate panel 14.
In this figure, the reinforcing member 20 is made of a rectangular steel plate bent along the length direction (direction orthogonal to the paper surface in FIG. 2A).

  The reinforcing member 20 includes a web 22 extending perpendicularly to the bottom steel plate 12 from the leg 21a welded to the bottom steel plate 12, and an inclined flange bent from the upper end of the web 22 at a predetermined upward angle θ with respect to the horizontal. 24. Although the upward angle θ is 5 degrees in this example, it is preferably close to the horizontal, for example, in the range of 2 degrees to 10 degrees, as long as there is no gap on the lower surface of the flange portion after placing the concrete.

In this example, the leg portion 21 a of the reinforcing member 20 is a horizontal portion 25 that is bent horizontally toward the inclined flange side at the lower end of the web 22. The reinforcing member 20 is fillet welded to the bottom steel plate 12 on both sides of the horizontal portion 25 to constitute an integrated steel plate panel 14.
With this configuration, since the lower surface of the horizontal portion 25 is in close contact with the upper surface of the bottom steel plate 12, the reinforcing member 20 can be easily positioned. Further, since the welded portions on both sides of the horizontal portion 25 are separated by the length (width) of the horizontal portion 25, the influence (for example, thermal strain) due to welding can be reduced.

  In this example, the inclined flange 24 is made of a single steel plate whose width is set so as to obtain a predetermined bending rigidity.

In the steel plate panel 14 having the above-described configuration, the fixed width of the bottom steel plate 12 is integrated, and each reinforcing member 20 has a secondary moment I and a section modulus Z. In FIG. 2A, when the horizontal line z is the neutral axis of the cross section and e1 and e2 are the distance from the neutral axis to the most peripheral, the cross section coefficient Z is expressed by I / e1 or I / e2. Further, the cross-sectional secondary moment I with respect to the neutral axis of the cross-section is represented by ∫y ² dA.
Therefore, it can be seen that the cross-sectional secondary moment I and the section modulus Z of the steel plate panel 14 increase as the cross-sectional area at a position far from the neutral axis z increases even if the area is the same.

In FIG. 2, the web 22 is provided with concrete holes 22a through which ready-mixed concrete can pass at a constant pitch (for example, 300 mm) in the length direction. This concrete hole 22a is processed before bending.
The inclined flange 24 is provided with air holes 24a through which air in the ready-mixed concrete can pass at a constant pitch (for example, 300 mm) in the length direction. This air hole 24a is also processed before bending.

  The concrete hole 22a and the air hole 24a are preferably provided with their positions shifted in the length direction. In this example, the concrete hole 22a is a circular hole (for example, a diameter of 60 mm) and the air hole 24a is also a circular hole (for example, a diameter of 10 mm), but may be another shape, for example, an ellipse.

  According to the configuration of the present invention described above, the reinforcing member 20 is made of a rectangular steel plate bent along the length direction, so that the height of the reinforcing member 20 and the inclined flange 24 are adjusted according to a predetermined floor slab thickness. The width and the inclination angle θ can be freely set. Thereby, a desired bending rigidity can be obtained with a predetermined thickness (height) with a small amount of a reinforcing material, and an optimum dimension in design can be easily set.

  Further, since the inclined flange 24 is bent at the upper end of the web 22 at a predetermined upward angle θ with respect to the horizontal, it is difficult to form a concrete gap on the lower surface of the flange portion.

  Furthermore, since the concrete hole 22a and the air hole 24a are processed before the bending in the processing step, the material (rectangular steel plate) can be cut, bent, and drilled in the same step, so that the processing cost can be reduced.

  Also, the bending process using a press can be performed without moving the machine and moving the machine, and the painting process (blasting, painting) can be performed continuously in the longitudinal direction, saving space and continuous work. Is possible, and the cost can be further reduced.

FIG. 3 is a connection structure diagram of the reinforcing member 20 of FIG.
The total length of the composite floor slab 10 is, for example, 10 m or more, and it is necessary to divide the composite floor slab and to connect them on site. The reinforcing member 20 of the present invention is provided with a plurality of bolt through holes (not shown) at both ends of the web 22 and the inclined flange 24, and the ends of the adjacent reinforcing members 20 are connected to each other by the connecting metal 30 and the bolt 32. It can be connected.
In addition, you may weld the periphery of the connection metal fitting 30 directly to the edge part of the reinforcing material 20, without using a volt | bolt.
With this configuration, even when the reinforcing material is divided and connected to divide the composite floor slab, the bending rigidity (secondary moment I and sectional modulus Z) of the connecting portion of the reinforcing material 20 is equal to or greater than that of the portion other than the connecting portion. And the use of the reinforcing member 20 shorter than the synthetic floor slab 10 can be made possible.

FIG. 4 is a diagram showing a second embodiment of the composite floor slab according to the present invention. In this example, the leg portion 21a of the reinforcing member 20 is the lower end surface of the web 22 and is fillet welded to the bottom steel plate 12 on both sides of one end (the lower end in the figure) of the folded rectangular steel plate, and the integrated steel plate panel 14 Is configured.
In this configuration, the horizontal portion 25 of the first embodiment is not provided, and the lower end surface of the web 22 is in close contact with the upper surface of the bottom steel plate 12. Since the horizontal part 25 of 1st Embodiment adheres to the bottom steel plate 12, it does not contribute so much with respect to the increase in bending rigidity. Therefore, with this configuration, it is possible to obtain the same bending rigidity with a smaller cross-sectional area than in the first embodiment, and it is possible to easily set the optimum dimensions in terms of design.
Other configurations and effects are the same as those in the first embodiment.

FIG. 5 is a diagram showing a third embodiment of the composite floor slab according to the present invention. In this example, the inclined flange 24 of the reinforcing member 20 is made of two steel plates that are folded and folded so as to obtain a predetermined bending rigidity.
The leg portion 21a of the reinforcing member 20 is the same as that of the first embodiment in this figure, but the horizontal portion 25 may be omitted as in the second embodiment.
With this configuration, the entire cross-sectional area of the inclined flange 24 located far from the neutral axis z can be set almost twice that of the first embodiment, so that equivalent bending rigidity can be obtained with a smaller cross-sectional area than the first embodiment. Therefore, the optimal dimensions can be set easily.
Other configurations and effects are the same as those in the first embodiment.

FIG. 6 is a diagram showing a fourth embodiment of the composite floor slab according to the present invention. In this figure, the concrete hole 22a of the reinforcing member 20 is a rectangular hole having a protruding portion 22b bent at an end portion.
The concrete holes 22a and the protrusions 22b are also preferably processed before bending. By making the concrete hole 22a a rectangular hole, the opening length can be set large without lowering the bending rigidity, and the passage of ready-mixed concrete can be facilitated.
Moreover, by providing the protrusion 22b, the bond with the concrete after hardening can be further strengthened.

  In addition, this invention is not limited to embodiment mentioned above, Of course, a various change can be added in the range which does not deviate from the summary of this invention.

It is a 1st embodiment figure of a synthetic floor slab by the present invention. It is detail drawing of the steel plate panel of FIG. It is a connection structure figure of the reinforcing material of FIG. It is 2nd Embodiment figure of the synthetic floor slab by this invention. It is 3rd Embodiment figure of the synthetic floor slab by this invention. It is 4th Embodiment figure of the synthetic floor slab by this invention. It is a typical sectional view of a synthetic floor slab. 1 is a configuration diagram of “steel bottom formwork and floor slab” of Patent Document 1. FIG. 1 is a configuration diagram of “steel skeleton structure of a steel-concrete composite floor slab” in Patent Document 2.

Explanation of symbols

10 composite floor slab, 12 bottom steel plate, 14 steel plate panel,
16 main reinforcement, 18 concrete,
20 reinforcements, 20a legs, 22 webs,
22a concrete hole, 22b protrusion,
24 inclined flange, 24a air hole,
25 horizontal parts, 30 connecting brackets, 32 bolts

Claims (6)

A flat bottom steel plate extending horizontally;
A composite floor slab having a plurality of reinforcing materials welded to the upper surface of the bottom steel plate in parallel with each other at intervals,
The reinforcing member is a rectangular steel plate bent along the length direction, and a web extending perpendicularly to the bottom steel plate from a leg welded to the bottom steel plate, and a predetermined upward direction with respect to the horizontal from the upper end of the web. angle the length of the bent one width direction to have a a long inclined flange than the length in the width direction of said legs, synthetic slab, characterized in that.   The composite floor slab according to claim 1, wherein the leg portion of the reinforcing material is a lower end surface of the web or a horizontal portion bent horizontally toward the inclined flange side at the lower end of the web.   2. The composite floor slab according to claim 1, wherein the inclined flange is made of one or two folded steel plates having a width set so as to obtain a predetermined bending rigidity. It consists of a rectangular steel plate bent along the length direction and extends perpendicularly to the bottom steel plate from the legs welded to the bottom steel plate, and is bent in one at a predetermined upward angle with respect to the horizontal from the upper end of the web. A plurality of reinforcing members each having an inclined flange whose length in the width direction is longer than the length in the width direction of the leg portion is welded to the upper surface of a horizontally extending flat plate-like bottom steel plate at intervals in parallel to each other; A method for reinforcing a composite floor slab characterized by the above.   A concrete hole through which fresh concrete can pass is provided in the web before bending, and an air hole through which air in the ready concrete can pass is provided in the inclined flange before bending. Item 5. The method for reinforcing a composite slab according to Item 4.   The method for reinforcing a composite floor slab according to claim 5, wherein the concrete hole is a circular hole, an elliptical hole, or a rectangular hole having a protruding portion bent at an end.

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