Deck slab and deck slab construction method

Abstract

To provide a deck slab and a deck slab construction method which can improve strength of the deck slab while reducing the floor height.SOLUTION: A first deck pate 6A, having an inverted end-closing shape 22 at an end part 21, can reduce the floor height by making the level of the bottom edge of the first deck plate 6A lower than the top edge of a girder 2. On the other hand, the other end part 23 of the first deck plate 6A does not have the inverted end-closing shape 22. Furthermore, a second deck plate 6B has at least one of a normal end-closing shape 33 and an open shape 24 at both end parts 31, 32 in the span direction D1. Thus, the region corresponding to the second deck plate, having no inverted end-closing shape 22, can secure the thickness of the concrete 7. This enables improvement of strength of the deck slab compared to the case of adopting the inverted end-closing shape 22 between a pair of girders 2.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a deck slab and a method for constructing a deck slab. [Background technology]

[0002] A conventional deck slab is known from Patent Document 1. This deck slab is equipped with a reverse end-closed deck plate in order to lower the floor height without increasing the construction work. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-40746 A Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, when using a reverse end-closed deck plate, the floor height can be lowered by lowering the bottom of the floor below the top of the girder. However, in a deck slab equipped with a reverse end-closed deck plate, the thickness of the concrete above the girder is thin. Therefore, there is a problem that shear failure is likely to occur in the structurally thin part, and the strength of the deck slab is reduced.

[0005] The present invention has been made to solve such problems, and has an object to provide a deck slab and a construction method for a deck slab that can improve the strength of the deck slab while lowering the floor height. [Means for solving the problem]

[0006] The deck slab of the present invention is a deck slab having a pair of first deck plates arranged spaced apart from each other in the span direction (of the first deck plates) and respectively joined to a pair of first beams, a second deck plate arranged between the pair of first deck plates in the span direction, and concrete provided on the first deck plate and the second deck plate, wherein the first deck plate has a reverse end closed shape only at one end joined to the first beam, and the second deck plate has at least one of a normal end closed shape and an open shape at both ends in the span direction.

[0007] In the deck slab according to the present invention, the first deck plate has an inverted end-closed shape only at one end where the first beam is joined. Therefore, since the first deck plate has an inverted end-closed shape at the end where the first beam is joined, the floor height can be lowered by dropping the lower end of the deck plate below the upper end of the main beam. On the other hand, the other end of the first deck plate does not have an inverted end-closed shape. Furthermore, the second deck plate has at least one of a normal end-closed shape and an open shape at both ends in the span direction. Therefore, the thickness of the concrete can be secured in the area corresponding to the second deck plate by not using an inverted end-closed shape. In this case, the strength of the deck slab can be improved compared to the case where an inverted end-closed shape is used for all of the first beams. As a result, the strength of the deck slab can be improved while lowering the floor height.

[0008] The other end opposite to the one end of the first deck plate may be joined to the second beam. In this case, the first deck plate can be supported at the end opposite to the end of the inverted end-closed shape.

[0009] Specifically, the first beam may be a major beam, and the second beam may be a minor beam.

[0010] The concrete does not need to have fire-resistant reinforcement in the area corresponding to the second deck plate. The second deck plate, which usually has either an end-closed shape or an open shape, can ensure the strength of the deck slab without using fire-resistant reinforcement. Therefore, by omitting the fire-resistant reinforcement from the area corresponding to the second deck plate, costs can be reduced.

[0011] The other end of the first deck plate may be joined to a second beam having a weight per unit length of 9.3 kg / m or more and 240 kg / m or less. In this case, costs can be reduced.

[0012] When performing structural calculations for the deck slab under simply supported conditions with pin support at both ends, the positive bending moment may be set to 69.4 kN m or less. In this case, the fire-resistant reinforcement in the area corresponding to the second deck plate can be omitted, resulting in cost reduction.

[0013] The support span of the deck slab in the span direction may be 3.4 m or less. In this case, the fire-resistant reinforcement in the area corresponding to the second deck plate can be omitted, which reduces costs.

[0014] Deck slab load is 6.0kN / m 2 In this case, the fire-resistant reinforcement in the area corresponding to the second deck plate can be omitted, and the cost can be reduced.

[0015] The value of the tensile section modulus is 50cm 3 / m or more, 550cm 3 / m or less, and the compression section modulus is set at 1350 cm 3 / m or more, 11000cm 3 / m or less, and the value of the second moment of area is set to 5000 cm 4 / m or more, 120000cm 4 / m or less. In this case, the fire-resistant reinforcement in the area corresponding to the second deck plate can be omitted, resulting in cost reduction.

[0016] The deck slab construction method of the present invention comprises a first step of arranging a pair of first deck plates so as to be spaced apart from each other in the span direction and joining each to a pair of first beams, a second step of placing a second deck plate between the pair of first deck plates in the span direction, and a third step of providing concrete on the first deck plate and on the second deck plate, wherein the first deck plate has a reverse end-closed shape only at one end joined to the first beam, and the second deck plate has at least one of a normal end-closed shape and an open shape at both ends in the span direction.

[0017] According to the deck slab construction method of the present invention, it is possible to obtain the same functions and effects as those of the above-mentioned deck slab. Effect of the Invention

[0018] According to the present invention, it is possible to provide a deck slab and a construction method for a deck slab that can improve the strength of the deck slab while lowering the floor height. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a schematic cross-sectional view of a deck slab according to an embodiment of the present invention as viewed from the width direction. [Diagram 2] FIG. 2 is a plan view of a deck slab. [Diagram 3] FIG. 2 is an enlarged cross-sectional view of the deck slab when viewed from the width direction. [Figure 4] 4 is a cross-sectional view of the deck slab taken along lines IVa-IVa, IVb-IVb, and IVc-IVc shown in FIG. 3, as viewed from the span direction. [Diagram 5] 1A is a perspective view of the reverse end-closed shape seen from below, FIG. 1B is a perspective view of the open shape seen from above, and FIG. 1C is a perspective view of the normal end-closed shape seen from above. [Figure 6] FIG. 11 is an enlarged cross-sectional view showing a deck slab according to a modified example. [Figure 7]FIG. 11 is an enlarged cross-sectional view showing a deck slab according to a modified example. [Figure 8] FIG. 11 is an enlarged cross-sectional view showing a deck slab according to a modified example. [Figure 9] 1 is a table showing the conditions of a structural test of a deck slab. [Figure 10] 13 is a table showing experimental results and comparison results with design values. [Figure 11] FIG. 13 is a diagram showing a test specimen of a deck slab. [Figure 12] 1 is a table showing test conditions for a fire resistance test. [Figure 13] 1 is a table showing test results of a fire resistance test. [Figure 14] FIG. 11 is a cross-sectional view of each type of deck slab as viewed from the width direction for comparison. [Figure 15] 13 is a table showing material unit prices. [Figure 16] 1 is a table showing a cost comparison between a deck slab according to a comparative example and a deck slab according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[0021] FIG. 1 is a schematic cross-sectional view of a deck slab 100 according to an embodiment of the present invention, as viewed from a width direction D2. FIG. 2 is a plan view of the deck slab 100. However, concrete 7 is omitted in FIG. 2. As shown in FIG. 1, the deck slab 100 is provided as a floor slab in a building. Both ends of the deck slab 100 are supported by a pair of girders 2. In addition, a plurality of small beams 3 (five in this example) are provided midway between the pair of girders 2. The deck slab 100 has a deck plate 6 and concrete 7 provided on the deck plate 6.

[0022] Here, the span direction D1 and width direction D2 of the deck plate 6 will be explained. The direction in which the peaks 6a and valleys 6b of the deck plate 6 extend is the span direction D1 of the deck plate 6, and the direction in which the peaks 6a and valleys 6b are aligned is the width direction D2 of the deck plate 6. In the following explanation, when simply referring to the "span direction" and "width direction", this refers to the span direction D1 and width direction D2 of the deck plate 6. In FIG. 1, the main beams 2 and the secondary beams 3 extend parallel to the width direction D2. Furthermore, the main beams 2 and the secondary beams 3 are arranged spaced apart from each other in the span direction D1.

[0023] Fig. 3 is an enlarged cross-sectional view of the deck slab 100 as viewed from the width direction D2. Figs. 4(a), 4(b), and 4(c) are cross-sectional views taken along lines IVa-IVa, IVb-IVb, and IVc-IVc shown in Fig. 3.

[0024] As shown in Figures 4(a) and (b), the deck plate 6 has alternating peaks 6a and valleys 6b in the width direction D2. The peaks 6a are provided so as to protrude upward from the bottom surfaces of the valleys 6b. The multiple peaks 6a extend parallel to each other in the span direction D1 while being spaced apart from each other in the width direction D2. The peaks 6a form both side walls of the valleys 6b.

[0025] The concrete 7 is poured onto the deck plate 6. The concrete 7 is filled inside the valleys 6b of the deck plate 6 up to a position higher than the upper surfaces of the peaks 6a. As a result, the concrete 7 has an upper surface that extends in the span direction D1 and width direction D2 above the deck plate 6. This upper surface becomes the upper surface 100a of the deck slab 100. The thickness t of the concrete 7 on the peaks 6a of the deck plate 6 is 50 mm to 100 mm.

[0026] As shown in FIG. 1, the deck slab 100 according to this embodiment has a pair of first deck plates 6A and a second deck plate 6B. The pair of first deck plates 6A are arranged to be spaced apart from each other in the span direction D1, and are deck plates 6 joined to a pair of girders 2, respectively. The second deck plate 6B is a deck plate 6 arranged between the pair of first deck plates 6A in the span direction D1. In this embodiment, the deck slab 100 has two second deck plates 6B, but the number is not particularly limited. Both ends of the first deck plate 6A in the span direction D1 are joined to the girder 2 and the small beam 3 adjacent to the girder 2, respectively. Both ends of the second deck plate 6B in the span direction D1 are joined to the small beam 3 arranged between the girders 2. When supported between the second deck plates 6B in the span direction D1, they are supported by the small beam 3.

[0027] Next, the first deck plate 6A and the second deck plate 6B will be described in detail with reference to FIG. 3 and FIG. 4. As shown in FIG. 3, the first deck plate 6A has an inverted end-closed shape 22 only at one end 21 in the span direction D1 where the main beam 2 is joined. The other end 23 in the span direction D1 of the first deck plate 6A is joined to the sub-beam 3. In this embodiment, the other end 23 of the first deck plate 6A has an open shape 24. Between the end 21 and the end 23, the cross-sectional shapes of the peaks 6a and the valleys 6b are constant and the general portion 11 extends in the span direction D1. The portion shown in FIG. 4(b) is not included in the general portion 11 because the cross-sectional shapes of the peaks 6a and the valleys 6b are not constant. The portion shown in FIG. 4(c) is not included in the general portion 11 because it does not have the peaks 6a and the valleys 6b. The second deck plate 6B has a normal end-closed shape 33 at both ends 31, 32 in the span direction D1. The both ends 31, 32 of the second deck plate 6B in the span direction D1 are joined to the small beams 3. The portion between the end 31 and the end 32 is configured as a general portion 11.

[0028] The shape of the end of the deck plate 6 will be described with reference to FIG. 5. FIG. 5(a) is a perspective view of the inverted end-closed shape 22 seen from below. The deck plate 6 has an upper flange 26 that forms the upper surface of the peak 6a and extends horizontally. The upper flange 26 has a flat joint 28 that extends from the tip of the peak 6a of the deck plate 6 to the girder 2 side. The joint 28 is placed on and fixed to the upper surface of the girder 2. The deck plate 6 has a lower flange 27 that forms the lower surface of the valley 6b and extends horizontally. The deck plate 6 has a side wall 29 that extends upward from the end of the lower flange 27 in the width direction D2 and is connected to the end of the upper flange 26 in the width direction D2. The pair of side walls 29 and the tip side of the lower flange 27 in the span direction D1 are closed by an inclined portion 30. The inclined portion 30 inclines upward as it approaches the tip side. The inclined portion 30 extends to the joint 28 of the upper flange 26.

[0029] 5(b) is a perspective view of the open shape 24 seen from above. The open shape 24 is a shape that opens at the tip in the span direction D1 while the cross-sectional shape of the general portion 11 is maintained at the tip. In the open shape 24, the tip of the side wall 29 is perpendicular to the horizontal direction.

[0030] 5(c) is a perspective view of the normal end-closed shape 33 as viewed from above. The lower flange 27 has a flat joint 34 that extends from the tip of the valley portion 6b of the deck plate 6 toward the minor beam 3. The joint 34 is placed on and fixed to the upper surface of the minor beam 3. The tip sides of the pair of side walls 29 and the upper flange 26 in the span direction D1 are closed by an inclined portion 36. The inclined portion 36 inclines downward as it approaches the tip side. The inclined portion 36 extends to the joint 34 of the lower flange 27.

[0031] As described above, the end 21 of the first deck plate 6A has an inverted end-closed shape 22. As a result, as shown in Fig. 3, the thickness of the concrete 7 at the location supported by the girders 2 is thinner than the thickness of the concrete in the general portion 11. The thickness of the concrete in the open shape 24 and the normal end-closed shape 33 is equal to the thickness of the concrete 7 in the general portion 11.

[0032] As shown in FIG. 4(a), the thickness of the concrete 7 in the general portion 11 is "t1". As shown in FIG. 4(b), the valley portion 6b in the inverted closed end shape 22 is disposed at a higher position than the valley portion 6b of the general portion 11. As a result, the thickness of the concrete 7 in the inverted closed end shape 22 is thinner than the thickness t1 of the concrete 7 in the general portion 11. As shown in FIG. 4(c), the joint portion 28 is disposed at a higher position than the valley portion 6b of the general portion 11. In this embodiment, the joint portion 28 is disposed at the same height as the peak portion 6a of the general portion 11. As a result, the thickness t2 of the concrete 7 in the joint portion 28 is thinner than the thickness t1 of the concrete 7 in the general portion 11.

[0033] As shown in FIG. 3, the concrete 7 has fire-resistant reinforcement 9 in the area corresponding to the first deck plate 6A. The fire-resistant reinforcement 9 is a reinforcing bar extending in the span direction D1. The fire-resistant reinforcement 9 extends in the span direction D1 so as to reach directly above the sub-beam 3. The end of the fire-resistant reinforcement 9 on the end side 21 is disposed at the end of the general portion 11 on the end side 21. The fire-resistant reinforcement 9 is disposed at a position lower than the peak portion 6a (see FIG. 4(a)). On the other hand, the concrete 7 does not have fire-resistant reinforcement 9 in the area corresponding to the second deck plate 6B. That is, the fire-resistant reinforcement 9 is not disposed above the second deck plate 6B.

[0034] The beam 3 may have a weight per unit length of 9.3 kg / m or more. Also, the beam 3 may have a weight per unit length of 240 kg / m or less.

[0035] In the deck slab 100, the support span in the span direction D1 may be 3.4 m or less. The support span in the span direction D1 is the dimension in the span direction D1 between the center position of the main beam 2 and the center position of the adjacent sub-beam 3, or the dimension in the span direction D1 between the center positions of the adjacent sub-beams 3 (indicated by "SP1" in FIG. 3).

[0036] The load capacity of deck slab 100 is 6.0kN / m 2 The following may be used.

[0037] The positive bending moment M of the deck slab 100 under simply supported conditions is expressed as M = WL^2 (W = live load kN / m2, L = support span m). For example, if the live load is doubled, the positive bending moment is doubled, and if the support span is doubled, the positive bending moment is quadrupled. Even if the live load exceeds 3.4m, it is possible to reduce the positive bending moment by, for example, reducing the live load, and still apply the system. Specifically, by setting M = 6.0 x 3.4^2 ≒ 69.4kN·m or less, it is possible to apply the system when the support span is over 3.4m or the live load is 6.0kN / m. 2 It may be super.

[0038] The tensile section modulus of the deck slab 100 is 50 cm 3 / m or more, 550 cm 3 The compressive section modulus of the deck slab 100 may be set to 1350 cm 3 / m or higher, 11000 cm 3 The value of the second moment of area of ​​the deck slab 100 may be set to 5000 cm 4 / m or more, 120000 cm 4 / m or less.

[0039] The shape of the end 23 of the first deck plate 6A and the shapes of both ends 31, 32 of the second deck plate 6B are not limited to the combination shown in FIG. 3. For example, the configuration shown in FIG. 6 may be adopted. In the example shown in FIG. 6, the end 23 of the first deck plate 6A has an open shape 24, and both ends 31, 32 of the second deck plate 6B have an open shape 24. The configuration shown in FIG. 7(a) may be adopted. In the example shown in FIG. 7(a), the end 23 of the first deck plate 6A has a normal end-closed shape 33, and both ends 31, 32 of the second deck plate 6B have a normal end-closed shape 33. In the example shown in FIG. 7(b), the end 23 of the first deck plate 6A has a normal end-closed shape 33, and both ends 31, 32 of the second deck plate 6B have an open shape 24.

[0040] The position of the fire-resistant reinforcement bar 9 is not limited to the position shown in Fig. 3. For example, as shown in Fig. 8(a), it may be placed at a higher position than the position of the fire-resistant reinforcement bar 9 shown in Fig. 3. The fire-resistant reinforcement bar 9 shown in Fig. 8(a) may be placed at a position above the upper end of the first deck plate 6A. As shown in Fig. 8(b), it may be placed closer to the girder 2 than the position of the fire-resistant reinforcement bar 9 in Fig. 8(a). The fire-resistant reinforcement bar 9 shown in Fig. 8(b) may be placed at a position that approaches the girder 2.

[0041] Next, the action and effect of the deck slab 100 according to this embodiment will be described.

[0042] As shown in FIG. 11, a test specimen of a deck slab 150 (upper drawing) having a deck plate 106 with an open shape 24 at both ends and a test specimen of a deck slab 151 (lower drawing) having a deck plate 107 with an inverted end-closed shape 22 at both ends are prepared. Both ends of each deck slab 150, 151 were supported. In the deck slab 151 having the deck plate 107 with the inverted end-closed shape 22, the thickness of the concrete 7 on the beam is thinner than that of the deck slab 150 shown in the upper drawing, so that shear failure is likely to occur in the structurally thin part, and it has been confirmed by an experiment that the strength of the deck slab is small. FIG. 9 shows the conditions of the structural test of the deck slab. Under such structural test conditions, loads were applied at two points sandwiching the center position, and the maximum strength was evaluated. FIG. 10 shows the experimental results and the results of comparison with the design value. As shown in FIG. 10, it can be seen that the maximum strength of the deck slab 151 with the inverted end-closed shape 22 is smaller than that of the deck slab 150 as an experimental value. Therefore, the allowable span and allowable live load are "deck slab with open shape 24 and deck slab with normal end-closed shape 33 > deck slab with reverse end-closed shape 22." Note that the deck slab with open shape 24 and the deck slab with normal end-closed shape 33 have the same performance because the concrete volume is the same.

[0043] It is known that the degree of fixation of the joint with the beam is lowered and the fire resistance performance is lowered in the case of a deck slab with a reverse end-closed shape 22 at both ends compared to the case of a deck slab with an open shape 24 at both ends and a deck slab with a normal end-closed shape 33 at both ends. As an example, a fire resistance test was performed under two types of test conditions shown in Figure 12, and the results shown in Figure 13 were obtained. The test method, selection of test specimens, and evaluation method of test results are based on the "Fire Resistance Test and Evaluation Procedures" issued by the designated performance evaluation organization. "No. 1" is a deck plate with an open shape 24 at both ends, and does not have fire-resistant reinforcement 9 installed, but the deflection amount is more than the specified value. Specifically, the experimental value (center deflection amount at 120 minutes) is 56% of the specified value.

[0044] On the other hand, when using a deck slab with an inverted end-closed shape22 at both ends as shown in “No. 2”, despite the inclusion of fire-resistant reinforcement bars (D13), which are advantageous in terms of fire resistance, the safety factor (1-test ratio) is only about 10%, which is barely enough to pass.

[0045] As described above, in the deck slab 200 having the deck plate 116 of the open shape 24 as shown in Fig. 14(a) and the deck slab 201 having the deck plate 117 of the normal end-closed shape 33 as shown in Fig. 14(b), under design conditions where fire-resistant reinforcement bars 9, which are reinforcement bars for improving fire resistance, are not required, a reduction in floor height cannot be realized. On the other hand, in the deck slab 202 having the deck plate 118 of the inverted end-closed shape 22 as shown in Fig. 14(c), there are cases where fire-resistant reinforcement bars 9 must be installed (over the entire deck). In this case, while there is a cost benefit from the reduction in floor height, the material cost and construction cost of the fire-resistant reinforcement bars 9 are required separately.

[0046] From the above findings, in the deck slab 100 according to this embodiment, the first deck plate 6A has the reverse end-closed shape 22 only at one end 21 that is joined to the girder 2 (first beam). Therefore, since the first deck plate 6A has the reverse end-closed shape 22 at the end 21 that is joined to the girder 2, the floor height can be lowered by dropping the lower end of the first deck plate 6A below the upper end of the girder 2. On the other hand, the other end 23 of the first deck plate 6A does not have the reverse end-closed shape 22. Furthermore, the second deck plate 6B has at least one of the normal end-closed shape 33 and the open shape 24 at both ends 31, 32 in the span direction D1. Therefore, in the region corresponding to the second deck plate 6B, the thickness of the concrete 7 can be secured by not using the reverse end-closed shape 22. In this case, the strength of the deck slab 100 can be improved compared to the case where the reverse end-closed shape 22 is used between the pair of girders 2 in the entirety. As a result, the strength of the deck slab 100 can be improved while the floor height is reduced.

[0047] Furthermore, the allowable load and span are increased by improving the strength of the deck slab 100. Therefore, as long as the design is within the range of the allowable load and span, appropriate design changes are possible, improving the degree of freedom in designing the deck slab 100.

[0048] One end 21 of the first deck plate 6A and the other end 23 opposite thereto may be joined to a small beam 3 (second beam). In this case, the first deck plate 6A can be supported by the end 23 opposite to the end 21 of the inverted end-closed shape 22.

[0049] Specifically, the first beam may be a main beam 2, and the second beam may be a minor beam 3.

[0050] The concrete 7 does not need to have fire-resistant reinforcement 9 in the area corresponding to the second deck plate 6B. The second deck plate 6B having at least one of the normal end-closed shape 33 and the open shape 24 can ensure the strength of the deck slab 100 without using the fire-resistant reinforcement 9. Therefore, by omitting the fire-resistant reinforcement 9 from the area corresponding to the second deck plate 6B, costs can be reduced.

[0051] The other end of the first deck plate 6A may be joined to a small beam having a weight per unit length of 9.3 kg / m or more and 240 kg / m or less. In this case, costs can be reduced.

[0052] The positive bending moment when structural calculations are performed on the deck slab 100 under the simple support condition with pin support at both ends may be set to 69.4 kN m or less. In this case, the fire-resistant reinforcement in the area corresponding to the second deck plate 6B can be omitted, resulting in cost reduction.

[0053] The support span of the deck slab 100 in the span direction may be 3.4 m or less. In this case, the fire-resistant reinforcement in the area corresponding to the second deck plate 6B can be omitted, and the cost can be reduced.

[0054] The load capacity of deck slab 100 is 6.0kN / m 2 In this case, the fire-resistant reinforcement in the area corresponding to the second deck plate 6B can be omitted, and the cost can be reduced.

[0055] The value of the tensile section modulus is 50cm 3 / m or more, 550cm 3 / m or less, and the compression section modulus is set at 1350 cm 3 / m or more, 11000cm 3 / m or less, and the value of the second moment of area is set to 5000 cm 4 / m or more, 120000cm 4 / m or less. In this case, the fire-resistant reinforcement in the area corresponding to the second deck plate 6B can be omitted, and the cost can be reduced.

[0056] The construction method of the deck slab 100 according to this embodiment includes a first step of arranging a pair of first deck plates 6A so as to be spaced apart from each other in the span direction and joining each to a pair of main girders 2 (first beams), a second step of arranging a second deck plate 6B between the pair of first deck plates 6A in the span direction, and a third step of providing concrete 12 on the first deck plate 6A and the second deck plate 6B, in which the first deck plate 6A has a reverse end-closed shape 22 only at one end 21 joined to the main girders 2, and the second deck plate 6B has at least one of a normal end-closed shape 33 and an open shape 24 at both ends in the span direction.

[0057] According to the construction method of the deck slab 100 according to this embodiment, it is possible to obtain the same functions and effects as those of the deck slab 100 described above.

[0058] As described above, in the deck slab 100 of this embodiment, depending on the design conditions, fire-resistant reinforcement may not be necessary, thereby enabling a reduction in floor height while minimizing the increase in steel costs and construction costs due to the addition of fire-resistant reinforcement.

[0059] FIG. 16 is a table showing a cost comparison between the deck slab according to the comparative example (FIG. 14(c)) and the deck slab according to the embodiment. The deck slab according to the comparative example has a deck plate with an inverted end-closed shape 22 over the entire length between the spans of the main girders. In the comparative example, fire-resistant reinforcement is required over the entire length. The deck slab according to the embodiment has the configuration shown in FIG. 3. In the embodiment, fire-resistant reinforcement is required partially. The unit price of materials is the value shown in FIG. 15, and was calculated based on the value of construction prices (April 2023). The subject is the deck plate, concrete, welded wire mesh, fire-resistant reinforcement, and small beams (H-shaped steel).

[0060] The calculation conditions are shown at the top of Figure 16. Nos. 1 to 3 are square grids of 20m in both the X and Y directions, and Nos. 4 to 6 are rectangular grids (aspect ratio 1:2) with the X direction at 10m. Calculations were performed by changing the number of girders between each span to 5, 7, and 9. The X direction corresponds to the "width direction D2" and the Y direction corresponds to the "span direction D1". The slab span l is the value obtained by dividing the Y direction span Ly, which corresponds to the deck plate laying direction, by the number of girders n plus 1. If three girders are installed between the girders, then four spans of slabs will be created.

[0061] In addition, for each case, the sub-beam sizes were calculated for three cross sections, specifically, for the H-shaped steel sections specified in JIS G 3192: "Standard Case 1: H400x200," "Case 2 with minimum weight (9.3kg / m): H100x50," and "Case 3 with maximum weight (240kg / m): H900x300," and compared.

[0062] The dotted areas show the price difference when changing from the comparative example to the working example, and the smaller the cross section of the beam, the greater the reduction rate. The reduction rate is about 4% at most, but the price difference is roughly 100,000 yen, which is "100,000 yen x number of applicable floor grids," so a large cost benefit can be expected for the entire building.

[0063] The present invention is not limited to the above-described embodiments.

[0064] For example, the above-mentioned deck slab structure is merely one example, and may be modified as appropriate without departing from the spirit of the present invention.

[0065] In the second deck plate 6B, the shapes of both ends are the same, but they may be different. For example, one may be an open shape and the other a normal end-closed shape.

[0066] The number of second deck plates 6B between the main girders is not particularly limited, and may be one, or may be three or more. The number of minor girders 3 is also not particularly limited.

[0067] [Form 1] A pair of first deck plates arranged to be spaced apart from each other in the span direction and joined to the pair of first beams, respectively; A second deck plate disposed between the pair of first deck plates in the span direction; A deck slab having concrete on the first deck plate and on the second deck plate, The first deck plate has an inverted end-closed shape only at one end portion joined to the first beam, The second deck plate is a deck slab having at least one of a normal end-closed shape and an open shape at both ends in the span direction. [Form 2] The deck slab of claim 1, wherein the first deck plate has one end and the other end opposite the one end joined to a second beam. [Form 3] The deck slab according to claim 1 or 2, wherein the first beam is a girder. [Form 4] The deck slab of claim 2, wherein the second beam is a sub-beam. [Form 5] 5. The deck slab according to any one of embodiments 1 to 4, wherein the concrete does not have a fire-resistant reinforcement in an area corresponding to the second deck plate. [Form 6] A deck slab as described in form 2, wherein the other end of the first deck plate is joined to the second beam having a weight per unit length of 9.3 kg / m or more and 240 kg / m or less. [Form 7] 7. The deck slab according to any one of embodiments 1 to 6, wherein the positive bending moment when structural calculations are performed on the deck slab under a simple support condition with both ends pin-supported is 69.4 kN·m or less. [Form 8] The deck slab according to any one of embodiments 1 to 7, wherein a support span of the deck slab in the span direction is 3.4 m or less. [Form 9] The load on the deck slab is 6.0 kN / m 2 A deck slab according to any one of the following embodiments 1 to 8. [Form 10] The value of the tensile section modulus is 50cm 3 / m or more, 550cm 3 / m or less, The compression section modulus is 1350 cm 3 / m or more, 11000cm 3 / m or less, The value of the second moment of area is 5000cm 4 / m or more, 120000cm 4 The deck slab according to any one of claims 1 to 9, wherein the thickness is set to 1 / m or less. [Form 11] A first step of disposing a pair of first deck plates so as to be spaced apart from each other in a span direction and joining the pair of first deck plates to the pair of first beams, respectively; a second step of disposing a second deck plate between the pair of first deck plates in the span direction; A third step of providing concrete on the first deck plate and on the second deck plate, The first deck plate has an inverted end-closed shape only at one end portion joined to the first beam, A deck slab construction method, wherein the second deck plate has at least one of a normal end-closed shape and an open shape at both ends in the span direction. [Explanation of symbols]

[0068] 2...main girder (first beam), 3...minor beam (second beam), 6A...first deck plate, 6B...second deck plate, 7...concrete, 9...fire-resistant reinforcement, 22...reverse end-closed shape, 24...open shape, 33...normal end-closed shape, 100...deck slab.

Claims

1. A pair of first deck plates arranged to be spaced apart from each other in the span direction and joined to the pair of first beams, respectively; A second deck plate disposed between the pair of first deck plates in the span direction; A deck slab having concrete on the first deck plate and on the second deck plate, The first deck plate has an inverted end-closed shape only at one end portion joined to the first beam, The second deck plate is a deck slab having at least one of a normal end-closed shape and an open shape at both ends in the span direction.

2. The deck slab according to claim 1 , wherein the other end opposite the one end of the first deck plate is joined to a second beam.

3. The deck slab of claim 1 , wherein the first beam is a girder.

4. The deck slab of claim 2 , wherein the second beam is a sub-beam.

5. 2. The deck slab of claim 1, wherein the concrete has no fire-resistant reinforcement in an area corresponding to the second deck plate.

6. 3. The deck slab according to claim 2, wherein the other end of the first deck plate is joined to the second beam having a weight per unit length of 9.3 kg / m or more and 240 kg / m or less.

7. 2. The deck slab according to claim 1, wherein the positive bending moment when structural calculations are performed under a simple support condition with both ends pin-supported is 69.4 kN·m or less.

8. 2. The deck slab according to claim 1, wherein the support span of the deck slab in the span direction is 3.4 m or less.

9. The load of the deck slab is 6.0 kN / m ２ A deck slab as described in claim 1, wherein:

10. The value of the tensile section modulus is 50 cm ３ / m or more, 550cm ３ / m or less, The compression section modulus is 1350 cm ３ / m or more, 11000cm ３ / m or less, The value of the second moment of area is 5000 cm ４ / m or more, 120000cm ４ The deck slab according to claim 1, wherein the thickness of the deck slab is set to 0.05 mm or less.

11. A first step of disposing a pair of first deck plates so as to be spaced apart from each other in a span direction and joining the pair of first deck plates to the pair of first beams, respectively; a second step of disposing a second deck plate between the pair of first deck plates in the span direction; A third step of providing concrete on the first deck plate and on the second deck plate, The first deck plate has an inverted end-closed shape only at one end portion joined to the first beam, A deck slab construction method, wherein the second deck plate has at least one of a normal end-closed shape and an open shape at both ends in the span direction.

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