Deck composite slab, and design method of deck composite slab

Abstract

To provide a deck composite slab capable of expanding an application range of the deck composite slab by suppressing cracking of concrete and improving cross-sectional performance, and a method for designing the deck composite slab.SOLUTION: A deck composite slab 100 is provided with deflection reinforcing bars 30 to bear tensile stress and suppress deflection at a position lower than a neutral axis NX of the deck composite slab 100. Since the deflection reinforcing bars 30 bear the tensile stress at the position lower than the neutral axis NX, the deflection is suppressed by suppressing the tensile stress acting on a concrete 2. Cracking in the concrete 2 can be suppressed. By placing the deflection reinforcing bars 30 at the position where the tensile stress acts, the cross-sectional performance of the concrete 2 can be demonstrated even in the region. The improved cross-sectional performance of the deck composite slab 100 can expand the application range of the deck composite slab 100.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a deck composite slab and a design method thereof.

Background Art

[0002] As a conventional deck composite slab, the one described in Patent Document 1 is known. This deck composite slab includes a deck plate in which a plurality of groove portions extend in the span direction, and concrete placed on the upper side of the deck plate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in the deck composite slab, it has been required to suppress the cracking of concrete and improve the cross-sectional performance to expand the application range of the deck composite slab.

[0005] The present invention has been made to solve such problems, and an object thereof is to provide a deck composite slab capable of suppressing the cracking of concrete and improving the cross-sectional performance to expand the application range of the deck composite slab, and a design method of the deck composite slab.

Means for Solving the Problems

[0006] The deck composite slab according to the present invention is a deck composite slab including a deck plate in which a plurality of groove portions extend in the span direction, and concrete placed on the upper side of the deck plate, wherein deflection reinforcing bars for bearing tensile stress and suppressing deflection are arranged at a position below the neutral axis of the deck composite slab.

[0007] The deck composite slab according to the present invention includes a deck plate having a plurality of groove portions extending in the span direction, and concrete placed on the upper side of the deck plate. When such a deck composite slab receives a load, tensile stress acts at a position below the neutral axis. On the other hand, in the deck composite slab, deflection reinforcing bars for bearing the tensile stress and suppressing deflection are arranged at a position below the neutral axis of the deck composite slab. Therefore, since the deflection reinforcing bars bear the tensile stress at a position below the neutral axis, the tensile stress acting on the concrete can be suppressed, and the deflection can be suppressed. Therefore, cracking of the concrete can be suppressed. Further, by arranging the deflection reinforcing bars at the position where the tensile stress acts, the cross-sectional performance of the concrete can also be exhibited in the area. Thus, by improving the cross-sectional performance of the deck composite slab, the application range of the deck composite slab can be expanded more than before. From the above, it is possible to suppress cracking of the concrete, improve the cross-sectional performance, and expand the application range of the deck composite slab.

[0008] The bottom surface portion of the deck plate may be configured in a flat plate shape. By configuring a deck composite slab using such a deck plate, the volume of concrete can be increased, so that the fire resistance performance can be improved.

[0009] The deflection reinforcing bars may be arranged in the groove portions. Since the groove portions of the deck plate are locations where tensile stress is likely to act, by arranging them at such positions, the deflection reinforcing bars can sufficiently bear the tensile stress, so that cracking of the concrete and the like can be suppressed.

[0010] The cover of the deflection reinforcing bars may be 25 mm or more. Thereby, since the deflection reinforcing bars do not approach the deck plate too much, the filling property and fixing property of the concrete with respect to the deck plate can be improved.

[0011] The underlay of the deflection reinforcing bar may be 38 mm or less. Within this range, regardless of the thickness of the deck composite slab, the deflection reinforcing bar will be arranged below the neutral axis, so the effect can be exerted.

[0012] The deflection reinforcing bar may be a reinforcing bar with a diameter of D10 or more. With such a diameter of the deflection reinforcing bar, the bond strength to the concrete can be maintained even under the tensile stress that can act within the long-term allowable load of the deck composite slab.

[0013] The design method of the deck composite slab according to the present invention is a design method of a deck composite slab including a deck plate in which a plurality of groove portions extend in the span direction and concrete provided on the upper surface side of the deck plate, and includes a step of arranging a deflection reinforcing bar in the deck composite slab, a step of calculating the position of the neutral axis, and a step of confirming the position of the deflection reinforcing bar with respect to the neutral axis. In the step of calculating the position of the neutral axis, the neutral axis is calculated based on the entire cross-section of the concrete and the deck plate.

[0014] According to the design method of the deck composite slab according to the present invention, since it is possible to arrange the deflection reinforcing bar below the neutral axis, the same actions and effects as those of the above-described deck composite slab can be obtained.

Effect of the Invention

[0015] An object of the present invention is to provide a deck composite slab capable of suppressing cracking of concrete, improving cross-sectional performance, and expanding the application range of the deck composite slab, and a design method of the deck composite slab.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[0018] FIG. 1 is a cross-sectional view of a deck composite slab 100 according to an embodiment of the present invention. As shown in FIG. 1, the deck composite slab 100 is configured by using a deck plate 1 as a formwork and placing concrete 2 on the upper side of the deck plate 1. Inside the concrete 2, a wire mesh-like reinforcing bar 3 arranged horizontally near the upper surface is arranged. In this specification, the direction in which the deck plate 1 extends may be referred to as the span direction D1, and the horizontal direction orthogonal to the span direction D1 may be referred to as the width direction D2.

[0019] The deck plate 1 includes a bottom surface portion 11 extending in the span direction D1 and the width direction D2, and a plurality of ridge portions 12 protruding upward from the bottom surface portion 11. The plurality of ridge portions 12 are arranged to be spaced apart from each other at a predetermined pitch in the width direction D2. Further, the plurality of ridge portions 12 each extend parallel to the span direction D1. The ridge portion 12 includes a vertical portion 13 extending straight vertically upward from the bottom surface portion 11, and an enlarged portion 14 provided at the upper end portion of the vertical portion 13. The enlarged portion 14 has an inverted triangular shape, and the upper surface 62a is enlarged as compared with the thickness of the vertical portion 13.

[0020] The ridge portion 12 is formed by bending a plate material that is the base material of the deck plate 1 upward from the bottom surface portion 11. From the end portion 11a of the bottom surface portion 11A on one side in the width direction D2 with respect to one ridge portion 12A, a rising portion 16A in which a part of the plate material rises vertically upward is formed. From the end portion 11b of the bottom surface portion 11B on the other side in the width direction D2 with respect to one ridge portion 12A, a rising portion 16B in which a part of the plate material rises vertically upward is formed. Since the end portion 11a of one bottom surface portion 11A and the end portion 11b of the other bottom surface portion 11B are arranged to be close to each other with substantially no gap, the rising portion 16A and the rising portion 16B are overlapped with each other to constitute one vertical portion 13. In the ridge portion 12A, the rising portion 16A and the rising portion 16B are constituted as a single continuous plate material. However, like the ridge portion 12B, the rising portion 16A and the rising portion 16B may be constituted by separate plate materials. In this case, they may be configured to be fitted to each other at the position of the enlarged portion 14. Each bottom surface portion 11 (the bottom surface portion 11 between a pair of ridge portions 12) has a long flat plate-like shape extending in the span direction D1, but each bottom surface portion 11 is connected to the adjacent bottom surface portion 11 in the width direction D2 via the ridge portion 12 with substantially no gap. Therefore, since the plurality of bottom surface portions 11 are connected in a state of being arranged in parallel in the width direction D2, the plurality of bottom surface portions are configured like a single flat plate extending in the width direction D2.

[0021] A pair of ridge portions 12 and a bottom surface portion 11 form a groove portion 20 having a U-shaped cross section that opens upward. A plurality of such groove portions 20 are arranged in parallel in the width direction D2 and extend in the span direction D1 with the same cross-sectional shape. When the concrete 2 is placed, the concrete enters each groove portion 20 and hardens in a state of being received. At this time, the concrete is in close contact with the inner surface of the groove portion 20, that is, the upper surface 11c of the bottom surface portion 11 and the outer surface of the ridge portion. Thereby, the concrete 2 and the deck plate are configured as an integral member. Note that the upper surface 2a of the concrete 2 is disposed at a position higher than the upper end 20a of the groove portion 20 (the upper end of the ridge portion 12). Therefore, the deck composite slab 100 has a lower region in which the deck plate 1 and the concrete 2 are integrated, and an upper region in which the concrete 2 extends upward from the groove portion 20 of the deck plate 1.

[0022] In this way, the flat-type deck plate 1 having the bottom surface portion 11 configured in a flat plate shape is used as a deck plate for a composite slab.

[0023] Generally, as shown in FIG. 2, when a load is applied to the deck composite slab 200 from above, since the deck plate 1 has the role of tension reinforcement, there is no need to provide structural tension reinforcement. Therefore, in the deck composite slab 200 according to the conventional example, since the concrete 2 on the tension side (lower side) of the deck valley portion is non-reinforced, when a load is applied, cracks (see crack CR) occur in the concrete 2 in the region (tension region E1 in FIG. 1), and the cross-sectional rigidity is reduced.

[0024] Therefore, in the deflection calculation of the deck composite slab 200 according to the conventional example, a design method using the cross-sectional performance value (= effective equivalent cross-sectional second moment) obtained by ignoring the tensile-side concrete in advance is adopted. The same applies to the deck composite slab 200 using the flat-type deck plate 1. That is, in the deck composite slab 200 of the conventional example in Fig. 3(b), for the tensile region E1 below the neutral axis NX, only the cross-sectional performance value of the deck plate 1 is considered, and in design, the concrete 2 in the tensile region E1 is not considered as an "ineffective part". That is, for the concrete 2, only the part in the compression region E2 above the neutral axis NX is considered, and the design is carried out assuming that there is no concrete in the tensile region E1. The specific content of the design method according to the conventional example will be described later.

[0025] Here, as a result of intensive research, the inventors have found that when the deflection reinforcement bars 30 for bearing tensile stress and suppressing deflection are arranged in the tensile-side region of the deck composite slab, early cracking of the concrete 2 on the tensile side can be prevented, and as shown in Fig. 3(a), the cross-sectional performance in which the entire cross-section including the concrete 2 in the tensile region E1 is effective can be exhibited. In the following description, arranging the deflection reinforcement bars 30 in the deck composite slab 100 means that the deflection reinforcement bars 30 are in a state of being embedded inside the concrete 2. Further, the deflection reinforcement bars 30 are provided so as to extend in the span direction D1. The deflection reinforcement bars 30 are arranged over the entire length of the deck plate 1 in the span direction D1. Further, the deflection reinforcement bars 30 may be provided at positions corresponding to all the groove portions 20, or may be provided at positions corresponding to only some of the groove portions 20. Alternatively, a plurality of deflection reinforcement bars 30 may be provided at a position corresponding to one groove portion 20.

[0026] Therefore, as shown in FIG. 1, deflection reinforcing bars 30 for bearing tensile stress and suppressing deflection are arranged at a position below the neutral axis NX of the deck composite slab 100. Note that the state where the deflection reinforcing bars 30 are arranged below the neutral axis NX means that the upper end portions of the deflection reinforcing bars 30 are arranged at positions lower than the neutral axis NX. Since the region below the neutral axis NX becomes the tensile region E1, in the tensile region E1, the deflection reinforcing bars 30 can bear the tensile stress. Even if the deflection reinforcing bars 30 are arranged slightly on the tensile side from the neutral axis NX, the deflection reinforcing bars 30 can exhibit their effects.

[0027] More preferably, the deflection reinforcing bars 30 may be arranged in the groove portion 20. That is, it is sufficient that the upper end portions of the deflection reinforcing bars 30 are arranged at positions lower than the upper end 20a of the groove portion 20. In this case, the deflection reinforcing bars 30 have a positional relationship such that both sides in the width direction D2 are sandwiched by the ridge portions 12.

[0028] The cover of the deflection reinforcing bars 30 may be 25 mm or more. As the deflection reinforcing bars 30 for bearing tensile stress, even if they are arranged slightly on the tensile side from the neutral axis NX, they are effective even if they are not in the groove portion 20, but the closer they are to the tensile edge (the bottom surface portion 11 of the deck plate 1), the more effectively they act. However, from the viewpoints of the filling property and fixing property of the concrete, it is preferable to secure a cover of 25 mm or more. In the "Reinforcement Design Guide for Reinforced Concrete Structures and Its Explanation 2010 (Architectural Institute of Japan)", among the regulations on the clear cover of the reinforcing bars, it is specified that the minimum is 25 mm as an absolute amount, so it can be understood that this dimension is preferable as the lower limit value. Specifically, the lower end of the deflection reinforcing bars 30 does not need to fall below the 25 mm line from the lower end of the deck plate.

[0029] Also, it is preferable that the underlay of the deflection reinforcing bar 30 is 38 mm or less. Among the deck plates that can be used, considering the one with the lowest neutral axis, even when the deflection reinforcing bar 30 with a predetermined thickness is arranged, if the upper end of the deflection reinforcing bar 30 is 38 mm or less from the lower end of the deck plate 1, the deflection reinforcing bar can be arranged below the neutral axis. In this way, by keeping the position of the deflection reinforcing bar 30 within this range, the deflection reinforcing bar 30 can exert its effect in deck composite slabs of any thickness.

[0030] The deflection reinforcing bar 30 may be a reinforcing bar with a diameter of D10 or more. With such a diameter of the deflection reinforcing bar 30, the bond strength to the concrete can be maintained even under tensile stress that can act within the range of the long-term allowable load of the deck composite slab. It can also be understood from the fact that in the "Reinforced Concrete Structure Calculation Standards and Explanation 2018 (Japan Society of Civil Engineers)", when the tensile reinforcing bar of a reinforced concrete slab is a deformed bar, it is specified to be D10 or more.

[0031] Next, a method for designing the deck composite slab 100 will be described. Before describing the method for designing the deck composite slab 100 according to the present embodiment, a method for designing the deck composite slab 200 according to the conventional example will be described. In the method for designing the deck composite slab 200 according to the conventional example, calculations are performed for a model as shown in Fig. 4(a). In the model of Fig. 4(a), only the upper side of the neutral axis is considered for the concrete, and the lower side of the neutral axis is ignored in the calculations. The explanations of the symbols that appear in the following descriptions are shown below. s a: Cross-sectional area of the deck plate (mm 2 / B) c a: Cross-sectional area of the concrete (mm 2 / B) B: Unit width of the deck plate, that is, groove pitch (mm) b: Dimension below the groove of the deck plate (mm) b1: Dimension above the groove of the deck plate (mm) bD : Width (mm) of the flat plate portion receiving the compression of the deck plate b e : Effective width (mm) of the compression portion of the deck plate D: Total dimension of the deck composite slab, or diameter of the plug weld s d: Distance (mm) from the upper end of the concrete of the deck composite slab to the centroid of the deck plate c d: Distance (mm) from the upper end of the concrete of the deck composite slab to the centroid of the concrete S E: Young's modulus of the steel material (N / mm 2 ) F c : Design standard strength of the concrete (N / mm 2 ) H: Total dimension (mm) of the deck plate f I: Second moment of the entire equivalent cross-section of the deck composite slab (mm 4 / B) s I: Second moment of the entire cross-section of the deck plate (mm 4 / B) s I e : Effective second moment of the cross-section of the deck plate (mm 4 / B) I n : Second moment of the cross-section of the concrete portion about the neutral axis of the deck composite slab (mm 4 / B) c I n : Effective equivalent second moment of the cross-section of the deck composite slab about the neutral axis (mm 4 / B) s I n : Equivalent second moment of the cross-section of the deck plate of the deck composite slab about the neutral axis of the deck composite slab (mm 4 / B) n: Ratio of Young's modulus of the steel material to that of the concrete S: Thickness (mm) of the concrete on the upper side of the deck plate t: Thickness (mm) of the deck plate x n : Distance from the upper end of the deck plate to the neutral axis (mm) X n : Distance from the upper end of the concrete of the effective equivalent cross-section of the deck composite slab to the neutral axis (mm) f X n : Distance from the upper end of the concrete of the full equivalent cross-section of the deck composite slab to the neutral axis (mm) Z c : Compression side cross-section coefficient of the deck plate (mm 4 / B) Z t : Tension side cross-section coefficient of the deck plate (mm 4 / B) c Z c : Compression side effective equivalent cross-section coefficient of the deck composite slab (mm 3 / B) c Z t : Tension side effective equivalent cross-section coefficient of the deck composite slab (mm 3 / B)

[0032] As shown in Fig. 5, first, the compressive stress C acting on the compression side in Fig. 4(a) is calculated using Equation (1) (step S110). Next, the tensile stress T acting on the tensile side in Fig. 4(a) is calculated using Equation (2) (step S120). Next, the neutral axis position X n is calculated using Equation (3) (step S130). Thus, the preparation for calculating the cross-sectional performance of the deck composite slab is completed. Note that when the position of the neutral axis is below the peak of the deck, a different calculation formula is required for the subsequent calculation formulas, which is omitted here.

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[0033] Next, start calculating the cross-sectional performance of the deck composite slab. First, using the neutral axis, calculate the second moment of inertia I of the effective cross-section of the concrete using Equation (4) (step S140). Next, using the neutral axis, calculate the equivalent second moment of inertia of the deck plate. n I. At this time, multiply sI by the ratio n of the Young's modulus (physical property value) of the steel to the concrete, convert it to the value of the steel, and use Equation (5), and then sum it up in the subsequent step S160 (step S150). Then, calculate the effective second moment of inertia of the deck composite slab. s I c I n using Equation (6). Thus, the calculation of the cross-sectional performance of the deck composite slab is completed.

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[0034] Next, perform calculations for the model in Fig. 3(b) using the above equations. At this time, for the calculation conditions of "Calculation conditions: Deck: Cynos - 1.0 mm, Yamakami thickness S: 110 mm, Deck unit width B: 400 mm", the values of "Calculation results: X" n : 77.8 mm, n I: 15562 cm 2 / m, s I: 101 cm 2 / m, s I n : 31011 cm 2 / m, c I n : 46573 cm 2 / m" are obtained.

[0035] Next, a design method for the deck composite slab 100 according to this embodiment will be described. Here, the model shown in Fig. 4(b) is used. Here, the concrete is considered for both the upper and lower parts of the neutral axis. As shown in Fig. 6, first, flexural reinforcement bars corresponding to tensile stress are arranged in the tensile side part of the deck composite slab (step S200). Next, the neutral axis position f X n is calculated by Equation (7) (step S210). Next, the arrangement of the flexural reinforcement bars is confirmed (step S220). Here, it is confirmed that the flexural reinforcement bars are arranged on the tensile end side of the neutral axis. Thus, the preparation for calculating the cross-sectional performance of the deck composite slab is completed. Next, the second moment of inertia I of the entire cross-section of the concrete is calculated using the neutral axis (step S230). Next, the equivalent second moment of inertia s I of the deck plate is calculated. Also, sI is multiplied by the ratio n of the Young's modulus (physical property value) of the steel to the concrete, and after converting to steel, sLn is calculated (step S240). Then, the equivalent second moment of inertia of the entire composite slab is calculated using Equation (8) (step S250).

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[0036] Next, using the above equations, calculations are performed for the model in Fig. 3(a). At this time, for the calculation conditions of "Calculation conditions: Deck: Cynos - 1.0 mm, Yamakami thickness S: 110 mm, Deck unit width B: 400 mm", the "Calculation results: f X n : 108 mm, s I: 101 cm 2 / m, c I: 25204 cm 2 / m, f I: 80667 cm 2 / m( cI n : A value of "1.73 times that of 46573" is obtained.

[0037] Here, regarding the calculation results for the models in FIGS. 3(a) and (b), the relationship between the span and the deflection is shown in FIG. 7. The calculation conditions are "Young's modulus ratio n of steel to concrete: 15, Young's modulus sE of steel: 205,000 N / mm 2 , deformation amplification factor K: 1.5". Also, FIG. 8 shows a table extracted for the main items of both.

[0038] Next, the operation and effects of the deck composite slab 100 according to this embodiment and its design method will be described.

[0039] The deck composite slab 100 according to this embodiment includes a deck plate 1 in which a plurality of groove portions 20 extend in the span direction D1, and concrete 2 placed on the upper side of the deck plate 1. When such a deck composite slab 100 receives a load, tensile stress acts at a position below the neutral axis NX. In contrast, in the deck composite slab 100, at a position below the neutral axis NX of the deck composite slab 100, a deflection reinforcing bar 30 for bearing the tensile stress and suppressing the deflection is arranged. Therefore, since the deflection reinforcing bar 30 bears the tensile stress at a position below the neutral axis NX, the tensile stress acting on the concrete 2 can be suppressed. Therefore, cracking of the concrete 2 can be suppressed. Also, by arranging the deflection reinforcing bar 30 at the position where the tensile stress acts, the cross-sectional performance of the concrete 2 can also be exhibited in this region. In this way, by improving the cross-sectional performance of the deck composite slab 100, the applicable range of the deck composite slab 100 can be expanded compared to the prior art. From the above, it is possible to suppress cracking of the concrete 2 and improve the cross-sectional performance to expand the applicable range of the deck composite slab 100.

[0040] The deck plate 1 may be configured such that the bottom surface portion 11 is flat. By constructing the deck composite slab 100 using such a deck plate 1, the concrete volume can be increased, and thus the fire resistance performance can be improved.

[0041] The deflection reinforcing bar 30 may be disposed within the groove portion 20. Since the groove portion 20 of the deck plate 1 is a location where tensile stress is likely to act, by disposing it at this position, the deflection reinforcing bar 30 can sufficiently bear the tensile stress, thereby suppressing cracks and the like in the concrete 2.

[0042] The covering of the deflection reinforcing bar 30 may be 25 mm or more. Thereby, since the deflection reinforcing bar 30 does not approach the deck plate 1 too closely, the filling property and the fixing property of the concrete 2 with respect to the deck plate 1 can be improved.

[0043] The covering of the deflection reinforcing bar 30 may be 38 mm or less. Within this range, regardless of the thickness of the deck composite slab 100, the deflection reinforcing bar 30 will be disposed below the neutral axis NX, and thus the effect can be exerted.

[0044] The deflection reinforcing bar 30 may be a reinforcing bar with a diameter of D10 or more. With such a diameter of the deflection reinforcing bar 30, the fixing force with respect to the concrete 2 can be maintained even under tensile stress that can act within the range of the long-term allowable load of the deck composite slab 100.

[0045] The design method of the deck composite slab 100 according to this embodiment is a design method of a deck composite slab 100 including a deck plate 1 in which a plurality of groove portions 20 extend in the span direction D1, and concrete 2 provided on the upper surface side of the deck plate 1, and includes a step of arranging deflection reinforcing bars 30 in the deck composite slab 100 (step S200), a step of calculating the position of the neutral axis NX (step S210), and a step of confirming the position of the deflection reinforcing bars 30 with respect to the neutral axis NX (step S220). In the step of calculating the position of the neutral axis NX, the neutral axis NX is calculated based on the entire cross section of the concrete 2 and the deck plate 1.

[0046] According to the design method of the deck composite slab 100 according to this embodiment, since the deflection reinforcing bars 30 can be arranged below the neutral axis NX, the same operations and effects as those of the above-described deck composite slab 100 can be obtained.

[0047] Fig. 9 shows the positive bending test results (load-deflection relationship) of the deck composite slab by the graph G2 of the conventional example of "without tension reinforcement" and the graph G1 of the example of "with tension reinforcement". The primary stiffness until cracks occur in the tensile side concrete is about the same in graphs G1 and G2, but it is polarized at the time when cracks occur (when exceeding 50 kN). The graph G1 of "with tension reinforcement" exceeds the initial stiffness calculated value (RC standard) even when exceeding the long-term allowable load, while the graph G2 of "without tension reinforcement" has its stiffness decreased below the initial stiffness calculated value (RC standard) before reaching the long-term allowable load. Note that the "RC standard" refers to "Reinforced Concrete Structure Calculation Standard and Explanation 2018 (Japan Society of Civil Engineers)".

[0048] The present invention is not limited to the above-described embodiments.

[0049] For example, in the above-described embodiment, as the configuration of the deck plate, a flat type deck plate as shown in Fig. 1 is exemplified, but the shape of the deck plate is not particularly limited. For example, for a deck plate of a type in which ridges and valleys alternate as shown in Fig. 4, tension reinforcing bars 30 may be inserted.

Explanation of Symbols

[0050] 1…Deck plate, 2…Concrete, 11…Bottom part, 20…Groove part, 30…Deflection reinforcing bar, 100…Deck composite slab.

Claims

1. A deck slab composed of three elements: a deck plate with a plurality of groove portions extending in the span direction, concrete placed on the upper side of the deck plate, and flexural reinforcement bars disposed in the groove portions of the deck plate, wherein the flexural reinforcement bars are disposed at a position below the neutral axis of the deck slab to bear tensile stress and suppress deflection, the cover of the flexural reinforcement bars is 38 mm or less, the deck plate has a flat bottom surface, and the ridge portions on both sides of the groove portions are formed by bending the plate material constituting the deck plate upward, the deck slab.

2. The flexural reinforcement bars are disposed in the groove portions, the deck slab according to Claim 1.

3. The cover of the flexural reinforcement bars is 25 mm or more, the deck slab according to Claim 1 or 2.

4. The flexural reinforcement bars are reinforcing bars of D10 or more, the deck slab according to any one of Claims 1 to 3.

5. A design method of a deck slab composed of three elements: a deck plate with a plurality of groove portions extending in the span direction, concrete provided on the upper surface side of the deck plate, and flexural reinforcement bars disposed in the groove portions of the deck plate, comprising: a step of disposing flexural reinforcement bars in the deck slab, a step of calculating the position of the neutral axis, and a step of checking the position of the flexural reinforcement bars with respect to the neutral axis, in the step of calculating the position of the neutral axis, the neutral axis is calculated based on the entire cross-section of the concrete and the deck plate, the cover of the flexural reinforcement bars is 38 mm or less, The design method of the deck composite slab is such that the bottom surface of the deck plate is configured in a flat plate shape, and the ridge portions on both sides of the groove portion are formed by bending the plate material constituting the deck plate upward.

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