Composite slab structure and construction method of constructing composite slab structure

Abstract

To design a composite slab structure as continuous support even if a deck plate is not continuous on a beam.SOLUTION: A composite slab structure (1) includes: a plurality of plate members (10) placed on a beam (H); and a concrete part (50) placed on the beam (H) and the plurality of plate members (10). The plate members (10) are bridged between the end beams (H1, H2) and an intermediate beam (H3) or adjacent intermediate beams (H3) avoiding continuity over the intermediate beam (H3) among at least three beams (H1, H2, H3). A composite mechanism (20) to be combined with the concrete part (50) is provided above the intermediate beam (H3).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a composite slab structure and a construction method for constructing the composite slab structure. [Background technology]

[0002] Conventionally, composite slab structures including deck plates, concrete, etc. have been used for the floors, ceilings, roofs, etc. of buildings. In the composite slab structure, a deck plate is placed over the main beams and sub-beams (steel beams) formed from H-shaped steel, and is fixed to the main beams and sub-beams (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-293835 Summary of the Invention [Problem to be solved by the invention]

[0004] In a composite slab structure, a single deck plate may span at least three beams, but may also span between end beams and intermediate beams so that the deck plate does not continue across the intermediate beam. In this case, even if the concrete constituting the composite slab structure is poured continuously across at least three beams, there is no member that can bear the negative bending moment generated above the intermediate beam, so it is not considered to be continuously supported but simply supported according to the structural design standards for composite slab structures. Therefore, it is necessary to shorten the span between beams, increase the height of the deck plate, or increase the thickness of the deck plate, which is a disadvantage in design.

[0005] Therefore, the present invention has been made in consideration of the above-mentioned problems, and aims to provide a technology that makes it possible to design a composite slab structure as a continuous support even when the deck plate is not continuous on the beam. [Means for solving the problem]

[0006] One aspect of the present invention is a composite slab structure comprising a plurality of plate sections placed on beams and a concrete section poured on the beams and the plurality of plate sections, wherein the plate sections are bridged between an end beam and an intermediate beam or between adjacent intermediate beams of at least three beams so as not to be continuous across the intermediate beam, and a composite mechanism with the concrete section is provided above the intermediate beam.

[0007] In addition, it is preferable that the synthesis mechanism is provided in a range in the vicinity of the intermediate beam where a negative bending moment occurs when the synthesis mechanism is considered to be a continuous support.

[0008] Furthermore, it is preferable that the bending moment Ma borne by the additional member constituting the combining mechanism satisfies Ma≧M2, where M2 is the negative bending moment.

[0009] In addition, it is preferable that the cross-sectional area at of the additional member satisfies at≧M2 / (ft×J), where M2 is the negative bending moment, ft is the allowable stress of the additional member, and J is the stress center distance obtained by multiplying the effective component d of the additional member by 7 / 8.

[0010] TIFF2024171265000002.tif28168

[0011] Moreover, it is preferable that the range R in which the synthesis mechanism is provided satisfies R≦Lx / 4, where Lx is the slab span along the extending direction of the plate portion.

[0012] Moreover, it is preferable that the range R in which the synthesis mechanism is provided satisfies R≦Lx / 8, where Lx is the slab span along the extending direction of the plate portion.

[0013] The additional member is preferably an iron wire or a reinforcing bar.

[0014] It is also preferable that the concrete structure includes reinforcing steel bars embedded in the concrete portion, and that the number of reinforcing steel bars as the additional member is greater than the number of reinforcing steel bars.

[0015] It is also preferable that the additional member includes reinforcing steel bars embedded in the concrete portion, and the total cross-sectional area of ​​the steel bars as the additional member is larger than the total cross-sectional area of ​​the reinforcing steel bars.

[0016] The plate portion is preferably a deck plate.

[0017] One aspect of the present invention is a construction method for constructing a composite slab structure on at least three beams, characterized in that it includes the steps of: bridging plate sections between end beams and the intermediate beams or between adjacent intermediate beams of the at least three beams so that the plate sections do not span the intermediate beam; placing a composite mechanism with a concrete section above the intermediate beam; and pouring concrete on the beams and the multiple plate sections. Effect of the Invention

[0018] According to the present invention, a composite slab structure can be designed as a continuous support even when the deck plate is not continuous on the beam. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a perspective view showing a composite slab structure, partially in section; [Diagram 2] FIG. 2 is a perspective view showing a deck plate in partial cross section. [Diagram 3] FIG. 2 is a perspective view showing a composite slab structure in which the concrete portion on the intermediate beam is not shown. [Figure 4] 2 is a schematic cross-sectional view of a composite slab structure viewed in a longitudinal direction L. FIG. [Diagram 5]This figure compares the bending moments when considered as simply supported and continuously supported in the design. [Figure 6] FIG. 13 is a diagram showing parameters required for calculating the size of the cross-sectional area required for an additional member. [Figure 7] FIG. 11 is a perspective view showing a composite slab structure in which the concrete portion on the intermediate beam is not shown in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that in the following description, the drawings are schematic, and the dimensional relationships and ratios of each element may differ from the reality. The drawings may also include parts with different dimensional relationships and ratios. The embodiment shown below is an example, and various embodiments may be adopted within the scope of the present invention.

[0021] The composite slab structure 1 comprises deck plates 10 as multiple plate material portions placed on beams H, and concrete portions 50 poured on the beams H and the multiple deck plates 10. In the longitudinal direction L of the composite slab structure 1, the deck plate 10 is bridged between end beams H1, H2 and intermediate beams H3 or between adjacent intermediate beams H3 so that it is not continuous across an intermediate beam H3 located between at least three beams H, and a composite mechanism 20 with the concrete portion 50 is provided above the intermediate beam H3.

[0022] [First embodiment] 1 is a perspective view showing a partial cross section of a composite slab structure 1 according to a first embodiment. The composite slab structure 1 according to the first embodiment is used, for example, for floors, roofs, ceilings, etc. of buildings. The composite slab structure 1 is formed, for example, on three beams H1, H2, and H3 formed of H-shaped steel, such as steel beams.

[0023] As shown in FIG. 1, each beam H1, H2, H3 is provided so that the extending directions are parallel to each other. Of the three beams H1, H2, H3, two beams H1, H2 are, for example, end beams, and the beam H3 provided between the two end beams H1, H2 is an intermediate beam. In the following, when the beams H1, H2 and the beam H3 are not distinguished from each other, they are simply described as "beam H". Note that the intermediate beam H3 provided between the two end beams H1, H2 is not limited to one, and multiple intermediate beams H3 may be provided. In the following description, the length direction L is the direction in which the deck plate 10 is spanned across the beams H, and the width direction W is the extension direction of the beams H and is a direction perpendicular to the direction in which the deck plate 10 is spanned across the beams H. In addition, the thickness direction (height direction) D is a direction perpendicular to the plane formed by the length direction L and the width direction W, and is the thickness direction of the composite slab structure 1.

[0024] As shown in FIG. 1, the composite slab structure 1 mainly comprises a deck plate 10, a composite mechanism 20, a welded wire mesh 30, and a concrete section 50.

[0025] The deck plate 10 is bridged between the end beam H1 and the intermediate beam H3 and between the end beam H2 and the intermediate beam H3 in the length direction L so as not to be continuous across the intermediate beam H3 (intermediate beam) located between at least three beams H, and is laid out on the beams H along the width direction W. That is, one end of the deck plate 10 in the extension direction is placed on one of the two adjacent beams H, and the other end of the deck plate 10 in the extension direction is placed on the other of the two adjacent beams H. The deck plate 10 may be placed on the beams H and joined to the beams H by spot welding or the like. The deck plate 10 may be a deck plate with continuous peaks and valleys as shown in FIG. 2, a flat deck with ribs formed on the flat plate portion, or a reinforced deck plate with a reinforced bar truss attached to the flat plate portion.

[0026] As shown in FIG. 2, the deck plate 10 has a peak portion 110, valley bottom portions 120 and 130, an inclined portion 140, and fitting portions (folded portions) 150 and 160.

[0027] The deck plate 10 has a wave-like shape in which peaks 110 and valley bottoms 120, 130 are alternately connected to each other in the width direction W via inclined portions 140 extending in the length direction L. A single plate of the deck plate 10 is made up of two peaks 110, three valley bottoms 120, 130, and two pairs of inclined portions 140, and is formed into a wave-like shape in a cross section taken along the width direction W. The deck plate 10 may be end-closed at both ends in the length direction L.

[0028] The peak portion 110 is, for example, a flat portion located above and spaced apart from the beam H in a state in which the slab is spanned across the beam H, and is a plate-like portion extending in the length direction L. The peak portion 110 has a groove 111. The groove 111 is formed in a concave shape toward the valley bottoms 120, 130. The groove 111 extends in the length direction L, and when there is only one groove 111, it is provided near the center in the width direction W.

[0029] The valley bottoms 120, 130 are parallel or approximately parallel to the peak portion 110, and are flat portions that are placed on the beam H when the beam H is spanned. The valley bottoms 120, 130 are flat, plate-like portions that extend in the length direction L. The valley bottoms 120, 130 do not overlap with the peak portion 110 in the width direction W.

[0030] Of the three valley bottoms 120, 130, the valley bottom 120 is sandwiched between the valley bottoms 130 in the width direction W and is provided in the center of the deck plate 10. The inclined portions 140 are continuous with both sides of the valley bottom 120 in the width direction W. The valley bottom 120 is formed to be wider in the width direction W than the valley bottom 130. The valley bottom 120 has a plurality of embossed portions 121 provided in the center or approximately in the center in the width direction W. The embossed portions 121 are provided at equal intervals along the length direction L and are formed to protrude toward the peak portion 110. The embossed portions 121 may also be formed as grooves extending along the length direction L and formed to protrude toward the peak portion 110. The embossed portions 121 and the grooves increase the rigidity of the deck plate 10 and stabilize the shape.

[0031] Valley bottoms 130 are provided at both ends in the width direction W of the deck plate 10. In the width direction W, each valley bottom 130 is continuous with an inclined portion 140 on the side of valley bottom 120. Fitting portions 150, 160 are provided at the ends of valley bottoms 130 opposite the side to which inclined portion 140 is continuous.

[0032] The inclined portions 140 are portions that connect the crest portion 110 and the valley bottoms 120, 130, and are flat, plate-like portions that extend in the length direction L. The inclined portions 140 extend obliquely from both end sides of the crest portion 110 toward the valley bottoms 120, 130 in the width direction W. The inclined portions 140 adjacent to each other in the width direction W extend in different directions from the crest portion 110 so as to be spaced apart from each other. The inclined portions 140 are inclined to form a predetermined angle, for example an obtuse angle, with respect to the crest portion 110 and the valley bottoms 120, 130.

[0033] A plurality of embossed portions 141 are formed on the inclined portion 140. The embossed portions 141 are provided at predetermined intervals along the longitudinal direction L. The embossed portions 141 are formed to protrude toward the valley bottoms 120, 130 to which the inclined portions 140 are continuous. The embossed portions 141 increase the rigidity of the deck plate 10 and stabilize its shape.

[0034] Bulging portions 142 are formed at the transitions between the valley bottoms 120, 130 and the slopes 140. The bulging portions 142 are portions of a pair of slopes 140 at one peak portion 110 that protrude to opposite sides. In a pair of slopes 140 that face each other across the valley bottom 120, the bulging portions 142 are formed to face each other and bulge in directions approaching each other. In addition, the bulging portions 142 formed on each side of the valley bottom 130 bulge to the side opposite the valley bottom 120.

[0035] A dovetail groove 143 extending along the length direction L is formed between the bulge portion 142 and the valley bottoms 120, 130. The cross section of the dovetail groove 143 along the width direction W is formed to be curved. In a pair of inclined portions 140 facing each other across the valley bottom 120, the dovetail grooves 143 are formed to face each other and are curved in directions away from each other, that is, toward the valley bottom 130. In addition, the dovetail grooves 143 formed on each side of the valley bottom 130 are curved toward the valley bottom 120. The dovetail grooves 143 increase the rigidity of the deck plate 10 and stabilize the shape.

[0036] The fitting portions 150, 160 are provided contiguous to each valley bottom 130. The fitting portions 150, 160 are used to connect adjacent deck plates 10 in the width direction W when constructing a slab. Specifically, the fitting portion 150 of one deck plate 10 and the fitting portion 160 of the other deck plate 10 fit together, thereby connecting the two deck plates 10 in the width direction W. The fitting portions 150, 160 are folded back to different sides.

[0037] The fitting portion 150 is provided at one valley bottom 130 and is folded back to the side opposite the peak portion 110. The fitting portion 160 is provided at the other valley bottom 130 and is folded back to the side of the peak portion 110. The deck plate 10 is connected to other deck plates 10 adjacent to each other in the width direction W via the fitting portions 150, 160.

[0038] As shown in FIG. 3 and FIG. 4, the composite mechanism 20 is integrated with the beam H and the concrete portion cast on the deck plate 10 to form a composite body with the concrete portion 50 above the intermediate beam H3. The composite mechanism 20 is, for example, an additional member added to a composite slab having the deck plate 10 and the concrete portion 50 and embedded in the concrete portion 50. The additional member 20 is, for example, formed of a rod member made of metal, specifically, a plurality of reinforcing bars 21, 22. The reinforcing bars 21, 22 are, for example, deformed reinforcing bars, and are arranged so as not to interfere with the welded wire mesh 30 in the region above the intermediate beam H3 among the upper part of the deck plate 10. More specifically, the reinforcing bars 21, 22 are provided in a range where a negative bending moment occurs near the intermediate beam H3. The reinforcing bars 21, 22 engage with the concrete portion 50 on the intermediate beam H3 to structurally connect the two deck plates 10 arranged in the length direction L.

[0039] The reinforcing bars 21 are provided in a range where a negative bending moment occurs near the intermediate beam H3 so that their extending direction is along the length direction L and is approximately parallel to the flange surface of the intermediate beam H3. The reinforcing bars 21 are provided at least above the intermediate beam H3 at predetermined intervals in the thickness direction D and at predetermined intervals along the length direction L. The reinforcing bars 21 are formed to be longer than the flange width of the intermediate beam H3 when placed on the intermediate beam H3. The reinforcing bars 22 are provided in an area near the intermediate beam H3 where a negative bending moment occurs, so that their extending direction is along the width direction W and is approximately parallel to the flange surface of the intermediate beam H3. The reinforcing bars 22 are provided so as to intersect with the multiple reinforcing bars 21 provided at predetermined intervals in the thickness direction D. When placed, the reinforcing bars 22 have a length approximately equal to the length of the beam H3 in the extending direction. That is, the reinforcing bars 21 and 22 are provided above the intermediate beam H3 so as to intersect each other at right angles to form a lattice shape. Here, the reinforcing bars 21 and 22 may be in contact with each other or may be spaced apart from each other. The reinforcing bars 21, 22 are provided via spacers on the deck plate 10 at a position higher than the peak 110 of the deck plate 10 and lower than the welded wire mesh 30. The reinforcing bars 21, 22 do not need to be provided at a position higher than the peak 110, but are provided at a position lower than the welded wire mesh 30 (on the deck plate 10 side).

[0040] As shown in FIG. 5, the reinforcing bar 21 preferably has a length covering the range where the negative bending moment M2 occurs near the intermediate beam H3. In particular, in FIG. 5, when the distance between the center of the intermediate beam H3 and the centers of the end beams H1 and H2 in the extension direction of the deck plate 10 is Lx, the reinforcing bar 21 is preferably placed in a range where R≦Lx / 4 from the center of the intermediate beam H3. This is because the negative bending moment M2 occurs within a range of Lx / 4 from the center of the intermediate beam H3, so that the reinforcing bars 21 and 22 cover the area where the negative bending moment M2 occurs as a whole, and the composite of the reinforcing bars 21 and 22 and the concrete part 50 can bear the negative bending moment M2. In addition, if there is no problem in terms of strength, the total amount of reinforcing bars used may be reduced by placing the reinforcing bar 21 in a range where R≦Lx / 8. Also, for example, the range where R≦Lx / 4 is set as the range in which M2 occurs here, but the range in which M2 occurs may be determined by a logical expression or analysis according to the actual situation. The reinforcing bars 21 and 22, which are provided at a predetermined interval in the thickness direction D, may or may not face each other in the thickness direction D, and the number of the reinforcing bars 21 and 22 is not particularly limited and may be, for example, one or three or more. In addition, if the reinforcing bar 21 alone can bear the negative bending moment M2, the reinforcing bar 22 does not need to be provided. In other words, the additional member 20 may be composed of the reinforcing bar 21 alone. The additional member 20 may be attached to the deck plate 10 in advance at a factory or the like using spacers and then transported to the construction site of the composite slab structure 1, or it may be attached to the deck plate 10 or beams H on site using spacers or the like, or it may be attached to the welded wire mesh 30. Note that the additional member 20 is composed of reinforcing bars 21, 22, which are deformed reinforcing bars, but the additional member 20 may use deformed wire welded wire mesh or reinforcing steel plates instead of the reinforcing bars 21, 22. Furthermore, the additional member 20 may be composed of members made of other materials, such as resin rod members.

[0041] 1, 3 and 4, the welded wire mesh 30 is embedded in the concrete portion 50 and is arranged above the deck plate 10 so as to extend in both the length direction L and the width direction W for the purpose of preventing the expansion of cracks in the concrete portion 50. Specifically, the welded wire mesh 30 is formed in a lattice shape using, for example, steel bar members or wires, and is placed on a spacer installed on the deck plate 10, and is located above the additional member 20 in the thickness direction D. Note that, in terms of design, the welded wire mesh 30 is not considered to be a structure of the composite slab structure 1.

[0042] The concrete portion 50 is formed by pouring and solidifying concrete on one surface (top surface) of the deck plate 10. The concrete portion 50 is poured so as to cover the deck plate 10, the reinforcing bars 21, 22, and the welded wire mesh 30, and after the concrete portion 50 has solidified, the reinforcing bars 21, 22, and the welded wire mesh 30 are embedded within the concrete portion 50. In other words, the deck plate 10 forms a composite body with the concrete portion 50 on the intermediate beam H3 via the reinforcing bars 21, 22.

[0043] FIG. 5 is a schematic diagram comparing bending moments when considered as simply supported and continuously supported in design. In FIG. 5, the magnitude and direction of moment M1 generated on the lower side of the deck plate 10 and moment M2 generated on the upper side of the deck plate 10 correspond to the distance and direction from the center line of the curve of each moment M1, M2 when the lower surface of the deck plate 10 is the center line. For example, a composite slab structure 100 without reinforcing bars 21, 22 as a composite mechanism is considered to be simply supported. In this case, when a load is applied to the composite slab structure 100 from the direction of the arrow, since there is no structure to bear the moment generated on the intermediate beam H3, for convenience, the moment generated on the intermediate beam H3 is considered to be zero, and the moment generated on the intermediate beam H3 is originally assumed to be moment M1 generated on the lower side between the end beam H1 and the intermediate beam H3 and between the end beam H2 and the intermediate beam H3, and is designed as simply supported. Since the moment M1 occurring on the lower side is expected to be larger than in the design for continuous support, it was necessary to bear the moment M1 by, for example, narrowing the span between beams H, increasing the thickness of the deck plate 10, or increasing the amount of concrete section 50.

[0044] In contrast, the composite slab structure 1 can be considered as a continuous support structure as a whole. In the composite slab structure 1, reinforcing bars 21, 22 (additional members 20) that serve as a composite mechanism 20 are provided on the intermediate beam H3. If the reinforcing bars 21, 22 have the strength to bear the moment M2 generated on the upper side of the intermediate beam H3, the reinforcing bars 21, 22 engage with the concrete portion 50 on the intermediate beam H3 and are structurally connected to the two deck plates 10 aligned in the length direction L, so that the composite slab structure 1 can be considered as a continuous support structure. Therefore, the moment (negative bending moment) M2 generated on the upper side of the intermediate beam H3 can be borne by the steel bars 21 and 22, so that the span between the end beams H1, H2 and the intermediate beam H3 can be made larger than in the case of simple support, the height of the deck plate 10 can be made lower than in the case of simple support, the thickness of the deck plate 10 can be made thinner than in the case of simple support, or the amount of concrete 50 can be reduced, thereby reducing costs and also improving the performance of the composite slab, such as by increasing the allowable load.

[0045] Fig. 6 is a diagram showing parameters required for calculating the size of the cross-sectional area at required for the additional member 20. Fig. 6(a) is a cross-sectional view of the composite slab structure 1 as viewed in the longitudinal direction L, and Fig. 6(b) is an enlarged cross-sectional view of the periphery of the intermediate beam H3 in Fig. 6(a). The composite slab structure 1 is provided so as to extend across the end beams H1, H2 and intermediate beam H3, while the deck plate 10 is bridged between the end beam H1 and intermediate beam H3 and between the end beam H2 and intermediate beam H3 so as not to be continuous across the intermediate beam H3, and the span between the end beam H1 and intermediate beam H3 and the span between the end beam H2 and intermediate beam H3 are each Lx. By placing the composite slab structure 1 on the end beams H1, H2 and intermediate beam H3, moments M1 and M2 are generated by the uniformly distributed load W generated by the weight of the composite slab structure 1 itself and loads such as loads acting on the composite slab structure (for example, self-weight, loads, loads due to finishing materials, etc.). Moment M1 occurs downward between end beam H1 and intermediate beam H3, and between end beam H2 and intermediate beam H3, and moment M2 occurs upward between end beam H1 and intermediate beam H3, and between end beam H2 and intermediate beam H3. The following formula is established for the moment (negative bending moment) M2 generated on the upper side between the end beam H1 and the intermediate beam H3 and between the end beam H2 and the intermediate beam H3. TIFF2024171265000003.tif8151 If the cross-sectional area of ​​the reinforcing bars 21 and 22 installed on the intermediate beam H3 is at, the allowable stress is ft, and the distance between the stress centers J is the distance from the compression edge, in other words, the effective component d multiplied by 7 / 8, then the following equation holds for the allowable moment Ma that the reinforcing bars 21 and 22 can bear. Ma = at × ft × J (2) Furthermore, since, for structural reasons, the magnitude of the allowable moment Ma of the reinforcing bars 21 and 22 must exceed the moment M2 generated on the upward side between the end beam H1 and the intermediate beam H3, and between the end beam H2 and the intermediate beam H3, the following equation holds: Ma ≧ M2 (3) From the above equations (2) and (3), it can be seen that the condition that the cross-sectional area at of the reinforcing bars 21 and 22 must satisfy is as follows: at ≧ M2 / (ft×J) (4) Therefore, when designing the composite slab structure 1 as a continuous support, the cross-sectional area at of the reinforcing bars 21, 22 adopted as the additional member 20 must satisfy the above formula (4). It should be noted that the cross-sectional area at does not have to be that of a single reinforcing bar, but rather that the total cross-sectional area of ​​multiple reinforcing bars satisfies the above formula (4).

[0046] Furthermore, from the above equations (1) and (3), it can be seen that the following equation holds for the conditions that the span between the end beam H1 and the intermediate beam H3 or the slab span Lx between the end beam H2 and the intermediate beam H3 must satisfy. TIFF2024171265000004.tif11153Therefore, in the present invention, when designing a composite slab structure as a continuous support, the slab span Lx between the end beam H1 and the intermediate beam H3 or the slab span Lx between the end beam H2 and the intermediate beam H3 must satisfy the above formula (5).

[0047] In addition, if the distance J between the stress centers of the reinforcing bars 21 and 22 is the distance from the compression edges of the reinforcing bars 21 and 22 used as the additional member 20, that is, the effective component, is d, then the following formula is established. J = 7 × d / 8 (6) From the above equations (4) and (6), it can be seen that the condition that the distance d from the compression edge of the reinforcing bars 21 and 22 must satisfy is as follows: d≧(8×M2) / (7×at×ft) (7) Therefore, when designing the composite slab structure 1 as a continuous support, the distance from the compression edges of the reinforcing bars 21, 22 used as the additional members 20, for example the distance d from the top of the intermediate beam, must satisfy the above formula (7). However, when ensuring the size of the distance d, care must be taken to ensure that the distance between the slab surface and the compression edges of the reinforcing bars 21, 22 used as the additional members 20 is not smaller than the size required by various laws and regulations. Moreover, although M2 is calculated by the above formula (1) here, M2 may be calculated by a logical formula or analysis according to the actual situation.

[0048] Next, a description will be given of a construction method for the composite slab structure 1. First, the deck plate 10 is laid across the beams H. Specifically, the deck plate 10 is laid across the beams H3 in the width direction W from the end beams H1 (laying across the beams H).

[0049] Next, the deck plate 10 is placed on the side of the beam H on which the deck plate 10 is not spanned, and the deck plate 10 is laid out to a predetermined position. Specifically, the deck plate 10 is laid out in the width direction W from the end beam H2 to the area of ​​the intermediate beam H3 (spanning the beam H). In this way, the deck plate 10 is bridged between the end beams H1, H2 and the intermediate beam H3 or between the adjacent intermediate beams H3 so as not to be continuous across the intermediate beam H3 among at least three beams. The deck plate 10 is preferably fixed to the beam H by welding or the like.

[0050] Next, above the intermediate beam H3, in the range where the negative bending moment M2 occurs near the intermediate beam H3, reinforcing bars 21 and 22 are placed, for example via a spacer, as additional members 20 constituting a composite mechanism. Next, the welded wire mesh 30 is placed above the deck plate 10 and above the reinforcing bars 21, 22, for example, via a spacer. At this time, the welded wire mesh 30 is placed so as not to interfere with the reinforcing bars 21, 22. Next, concrete is poured onto the beam H and the deck plate 10 to form the concrete section 50. Here, the concrete section 50 is poured so that the reinforcing bars 21, 22 and the welded wire mesh 30 are buried to a predetermined depth. At this time, the composite slab and the beam H are structurally joined by headed studs, burnt plug welding, driven rivets, bolts, or other welding. Through the above steps, the composite slab structure 1 is constructed.

[0051] According to the composite slab structure 1 described above, since the composite mechanism 20 with the concrete portion 50 is provided above the intermediate beam H3, even if the deck plate 10 is not provided so as to be continuous across the intermediate beam H3, the composite slab structure can be designed as a continuous support rather than a simple support as a whole, and the composite slab structure 1 can be regarded as a continuously supported composite slab structure 1 as a whole. This makes it possible to, for example, make the span between the end beams H1, H2 and the intermediate beam H3 larger than in the case of a simple support, to make the height of the deck plate 10 lower than in the case of a simple support, to make the plate thickness of the deck plate 10 thinner than in the case of a simple support, to reduce costs, to reduce the amount of the concrete portion 50, and to improve the performance of the composite slab, such as by increasing the allowable load. Furthermore, by providing the additional member 20 in the area where the negative bending moment M2 occurs near the intermediate beam H3, the composite slab structure 1 can be considered as a continuous support not only in the structural design but also in the fire resistance design, improving the fire resistance. Furthermore, in the fire resistance design, the fire resistance of the composite slab, which can be considered as a continuous support from the beginning, can be further strengthened by providing the additional member 20.

[0052] [Second embodiment] Next, a second embodiment of the present invention will be described. As shown in FIG. 7, the second embodiment is a composite slab structure 1A in which reinforcing bars 40 are added to the space formed by valley bottoms 120, 130 and an inclined portion 140 of the deck plate 10. The reinforcing steel bar 40 is integrated with the concrete portion 50 to form a composite body with the concrete portion 50. The reinforcing steel bar 40 is added, for example, to a composite slab having the deck plate 10 and the concrete portion 50, and embedded in the concrete portion 50. The reinforcing steel bar 40 is formed, for example, from reinforcing bars 41, 42. The reinforcing bars 41, 42 are, for example, deformed reinforcing bars, and are arranged so as not to interfere with the additional member 20 or the welded wire mesh 30. More specifically, the reinforcing bars 41, 42 are provided on the beam H and the deck plate 10.

[0053] The reinforcing bars 41 are provided so that their extension direction is along the length direction L and is approximately parallel to the upper surfaces of the valley bottoms 120, 130 of the deck plate 10. The reinforcing bars 41 are provided above the valley bottoms 120, 130 at predetermined intervals in the thickness direction D and at predetermined intervals along the length direction L. The reinforcing bars 41 are provided not only above the deck plate 10 but also above the beams H. The reinforcing bars 42 are provided so that their extension direction is along the width direction W and is approximately parallel to the upper surfaces of the valley bottoms 120, 130 of the deck plate 10. The reinforcing bars 42 are provided so as to intersect with the multiple reinforcing bars 41 that are provided at predetermined intervals in the thickness direction D. The reinforcing bars 42 are formed to a length that fits between the opposing inclined portions 140 of the deck plate 10 when placed. That is, the reinforcing bars 41 and 42 are provided above the valley bottoms 120 and 130 so as to intersect each other at right angles to form a lattice shape. Here, the reinforcing bars 41 and 42 may be in contact with each other or may be spaced apart from each other. The reinforcing bars 41, 42 are provided at a position lower than the welded wire mesh 30 via spacers provided on the deck plate 10. Since the reinforcing bars 40 reinforce the deck plate 10, they may be provided only above the deck plate 10. In this case, the number of reinforcing bars 21, 22 as the additional members 20 should be greater than the number of reinforcing bars 41, 42. This allows the vicinity of the intermediate beam H3 where the negative bending moment M2 occurs to be reinforced more strongly than other portions. Furthermore, when the reinforcing bars 40 are provided only above the deck plate 10, the total cross-sectional area of ​​the reinforcing bars 21, 22 as the additional members 20 should be greater than the total cross-sectional area of ​​the reinforcing bars 41, 42. This allows the vicinity of the intermediate beam H3 where the negative bending moment M2 occurs to be reinforced more strongly than other portions. Note that if reinforcing bar 41 alone is sufficient as reinforcing bar 40, reinforcing bar 42 does not need to be provided. This is because reinforcing bar 41 alone can bear negative bending moment M2. Furthermore, if reinforcing bar 41 is provided in the range where moment M1 acts, it can bear moment M1, which makes it possible, for example, to lower the height of deck plate 10 or reduce the plate thickness of deck plate 10 to reduce costs, reduce the amount of concrete portion 50, and further improve the performance of the composite slab, such as by increasing the allowable load.

[0054] According to the composite slab structure 1A described above, in addition to achieving the same effects as the first embodiment, the composite slab structure 1A can be further strengthened by providing reinforcing bars 40, so that the span between the end beams H1, H2 and the intermediate beam H3 can be made larger than in the composite slab structure 1 in the first embodiment, the height of the deck plate 10 can be lowered, and the plate thickness of the deck plate 10 can be made thinner, thereby reducing costs, and further, the performance of the composite slab can be improved, such as by increasing the allowable load.

[0055] <Other> Although the preferred embodiment of the present invention has been described, the present invention is not limited to the above embodiment, and includes all aspects included in the concept and claims of the present invention. In addition, each configuration may be appropriately selected and combined so as to achieve at least a part of the above-mentioned problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiment may be appropriately changed depending on the specific use mode of the present invention. For example, as an alternative to reinforcement by the additional member 20 or the reinforcing bar 40, if the reinforcing effect of the welded wire mesh 30 alone can sufficiently satisfy the reinforcement required in design, etc., the additional member 20 or the reinforcing bar 40 may not be provided. In addition, when there are at least two beams, the deck plate is simply supported in the absence of an intermediate beam. At this time, by arranging the additional member 20 or the reinforcing bar 40 on the end beam, there is a member that bears the negative bending moment on the end beam, and the degree of fixation between the deck composite slab and the beam is increased, so that a negative bending moment M2 is generated on the end beam, and the moment M1 decreases depending on the ratio, so that the cost of the composite slab can be reduced and the performance can be improved. Also, here too, for example, as an alternative to reinforcement by additional members 20 or reinforcing bars 40, if the reinforcing effect of the welded wire mesh 30 alone is sufficient to meet the reinforcement required for design, etc., then additional members 20 or reinforcing bars 40 do not need to be provided. [Explanation of symbols]

[0056] 1, 1A Composite slab structure 10 Deck plate 20 Additional Materials 21 Reinforcing bar (extending in the length direction L) 22 Reinforcing bar (extending in width direction W) 30 Welded wire mesh 40 Reinforcement bars 50 Concrete Section

Claims

1. A composite slab structure comprising a plurality of plate sections placed on a beam, and a concrete section poured on the beam and the plurality of plate sections, The plate portion is bridged between an end beam and an intermediate beam or between adjacent intermediate beams among at least three beams so as not to be continuous across the intermediate beam, A composite slab structure characterized in that a composite mechanism with the concrete section is provided above the intermediate beam.

2. 2. The composite slab structure according to claim 1, wherein the composite mechanism is provided in an area in which a negative bending moment occurs near the intermediate beam when the composite mechanism is considered as a continuous support.

3. The bending moment Ma borne by the additional member constituting the composite mechanism is expressed as follows, when the negative bending moment is M2: Ma ≧ M2 3. The composite slab structure of claim 2 .

4. The cross-sectional area at of the additional member is expressed as follows, where M2 is the negative bending moment, ft is the allowable stress of the additional member, and J is the stress center distance obtained by multiplying the effective component d of the additional member by 7 / 8: at ≧ M2 / (ft × J) 4. The composite slab structure of claim 3,

5. The slab span Lx along the extension direction of the plate portion is expressed as follows, where Ma is the bending moment borne by the additional member and W is the uniformly distributed load on the beam due to the composite slab structure:

4. The composite slab structure of claim 3,

6. The range R in which the synthesis mechanism is provided is, when the slab span along the extending direction of the plate portion is Lx, R≦Lx / 4 3. The composite slab structure of claim 2 .

7. The range R in which the synthesis mechanism is provided is, when the slab span along the extending direction of the plate portion is Lx, R≦Lx / 8 3. The composite slab structure of claim 2 .

8. The composite slab structure according to claim 3, wherein the additional member is an iron wire or a reinforcing bar.

9. A reinforcing steel bar is embedded in the concrete portion, The composite slab structure according to claim 8, characterized in that the number of the additional steel bars is greater than the number of the reinforcing steel bars.

10. A reinforcing steel bar is embedded in the concrete portion, The composite slab structure according to claim 8, wherein the total cross-sectional area of ​​the steel bars as the additional members is greater than the total cross-sectional area of ​​the reinforcing steel bars.

11. The composite slab structure according to any one of claims 1 to 10, characterized in that the plate portion is a deck plate.

12. A construction method for constructing a composite slab structure on at least three beams, comprising: A step of bridging a plate portion between an end beam and the intermediate beam or between adjacent intermediate beams among at least three beams so as not to be continuous across the intermediate beam; A step of placing a mechanism for combining the intermediate beam with a concrete portion above the intermediate beam; Pouring concrete on the beam and the plurality of plate portions; A construction method for constructing a composite slab structure, comprising:

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