Calculation device, calculation method, and calculation program

Abstract

A calculation device, calculation method, and calculation program are provided that can improve the construction efficiency and reduce the construction costs of the laid slab construction method or precast RC beams. [Solution] The calculation device 10 is equipped with a first calculation unit 15, a second calculation unit 16, and a memory unit 13 that stores first data Da1 and second data Da2 for each type of flat deck 1, which are determined by the allowable stress fb, the plate thickness 2T of the flat deck 1, and the rib height 3H of the rib 3 in the out-of-plane direction (third direction Z).In the calculation device 10, the first calculation unit 15 calculates the first allowable load P1 of the flat deck 1 based on the first data Da1, and calculates the second allowable load P2 of the flat deck 1 based on the second data Da2.The second calculation unit 16 calculates the design allowable stress fb2 by dividing the allowable stress fb by a value β obtained by dividing the first allowable load P1 by the second allowable load P2.

Description

[Technical Field]

[0001] The present invention relates to a calculation device, a calculation method, and a calculation program, and more specifically to a calculation device capable of performing calculations for using deck plates in the slab-laying method or for precast RC (Reinforced Concrete) beams, etc., a calculation method for using deck plates in the slab-laying method or for precast RC (Reinforced Concrete) beams, etc., and a calculation program for executing the calculation method. [Background technology]

[0002] BACKGROUND ART Deck plates are sometimes used as formwork for implementing a laid slab method for constructing underground beams or the like, or for precast RC beams or the like (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-83601 Summary of the Invention [Problem to be solved by the invention]

[0004] Deck plates (hereinafter referred to as "flat decks") that include a flat surface for pouring concrete and multiple ribs that protrude perpendicular to the flat surface and extend in one of the in-plane directions of the flat surface (hereinafter referred to as "flat decks") are sometimes used as formwork for implementing the slab-laying method or as deck plates used for precast reinforced concrete beams, etc. (for convenience, these will be referred to as "deck plates for slab-laying, etc."). In a typical flat deck, the ribs do not extend to both ends of the flat deck in the direction in which the ribs extend (hereinafter referred to as the "rib extension direction"). That is, the ends of the flat deck that are on the extension line of the ribs in the rib extension direction are so-called end-closed sections, in which certain portions of the metal plate forming the flat deck are folded and flattened to prevent the ribs from interfering with the beams when the flat deck is laid across them.

[0005] The flat deck is spanned over the beam with an overlapping allowance that extends from its end in the rib extension direction (this end includes the end of the end-closed portion opposite the rib side in the rib extension direction) over a predetermined length in the rib extension direction. When the flat deck is used normally and not in a laid slab construction method, the overlapping allowance is, for example, about 50 mm. On the other hand, when the flat deck is used as a deck plate for a laid slab, etc., the overlapping allowance is about 30 mm, for example, to compensate for the loss of the beam cross section due to the deck plate being swallowed up, and to ensure space for the stirrups protruding from the underground beam.

[0006] In order to ensure the required rigidity and strength as a formwork for pouring concrete, it is generally recommended that the length of the end-closed portion excluding the overlapping portion (hereinafter referred to as the "offset portion") in the rib extension direction be 40 mm or less. The length of the end-closed portion of a typical flat deck in the rib extension direction is, for example, about 85 mm. When a flat deck is normally used, the overlapping portion is, for example, about 50 mm, as mentioned above, so the length of the offset portion in the rib extension direction is 40 mm or less.

[0007] On the other hand, when a flat deck is used as a deck plate for laid slabs, etc., the overlap length is about 30 mm as mentioned above, so if a regular flat deck is used, the length of the offset section will exceed 40 mm. Therefore, in the past, when using a flat deck as a deck plate for laid slabs, etc., it was necessary to prepare a custom-made product with an end-closed section shorter than a regular flat deck in order to keep the offset section length to 40 mm or less. This resulted in an increase in the lead time required to manufacture the custom-made product, which in turn tended to reduce the construction efficiency of the laid slab method and increase construction costs.

[0008] The present invention has been made in consideration of the above points, and one example of its objective is to provide a calculation device, a calculation method, and a calculation program that can improve the construction efficiency and reduce the construction costs of the slab-laying method or precast RC beams, etc. [Means for solving the problem]

[0009] (1): The arithmetic device of the present invention is a arithmetic device for performing calculations related to a flat deck, the flat deck comprising a flat surface for pouring concrete, a plurality of ribs protruding from the flat surface in an out-of-plane direction and extending in an in-plane direction of the flat deck, and end-closed portions extending from both end portions of the flat deck in the rib extension direction in a first length in the rib extension direction in which the ribs extend, the end-closed portions including overhang portions extending from the end portions of the flat deck in the rib extension direction in a second length and placed on a beam, and offset portions between the overhang portions and the ribs in the rib extension direction, the arithmetic device comprising a first arithmetic unit, a second arithmetic unit, and a memory unit for storing data on allowable stress, and first data and second data for each type of the flat deck determined by the plate thickness of the flat deck and the height of the ribs in the out-of-plane direction. the first data is data correlating a load in the out-of-plane direction applied to the flat deck when the length of the offset portion in the rib extension direction is a third length with a displacement of the flat deck in the out-of-plane direction when the load is applied, the second data is data correlating a load in the out-of-plane direction applied to the flat deck when the length of the offset portion in the rib extension direction is a fourth length longer than the third length with a displacement of the flat deck in the out-of-plane direction when the load is applied, the first calculation unit calculates a first allowable load of the flat deck based on the first data and calculates a second allowable load of the flat deck based on the second data, and the second calculation unit calculates a design allowable stress by dividing the allowable stress by a value obtained by dividing the first allowable load by the second allowable load.

[0010] (2): The arithmetic unit of (1) further includes a third arithmetic unit. The third arithmetic unit calculates a division value obtained by dividing the value obtained by subtracting the second allowable load from the first allowable load by a first natural number N1 (N1 ≥ 2), and then adds the second allowable load to the value obtained by multiplying the division value by a second natural number N2 (1 ≤ N2 < N1) to calculate a first value.

[0011] (3): The arithmetic unit of (2) further includes a fourth arithmetic unit. The fourth arithmetic unit calculates a linear function based on the first allowable load, the displacement corresponding to the first allowable load, the second allowable load, and the displacement corresponding to the second allowable load, and calculates a second value by substituting the first value into the linear function.

[0012] (4): In the arithmetic unit of (2) or (3), the first natural number N1 may be 7.

[0013] (5): In any of the arithmetic units of (1) to (4), the third length may be 40 mm.

[0014] (6): In any of the arithmetic units of (1) to (5), the fourth length may be 110 mm.

[0015] (7): The calculation method of the present invention is a calculation method for performing calculations related to a flat deck. The flat deck includes a flat surface for placing concrete, a plurality of ribs protruding in a direction out of the plane of the flat surface and extending in the in-plane direction of the flat surface, and end closure portions extending from both ends of the flat deck in the rib extension direction over a first length in the rib extension direction. The end closure portion includes a bearing portion that extends from the end of the flat deck in the rib extension direction over a second length and is placed on a beam, and an offset portion between the bearing portion and the rib in the rib extension direction. The calculation method includes a storage step of storing first data and second data for each type of the flat deck determined by the allowable stress data, the plate thickness of the flat deck, and the height of the rib in the out-of-plane direction; a first calculation step of calculating a first allowable load of the flat deck based on the first data and calculating a second allowable load of the flat deck based on the second data; and a second calculation step of calculating a design allowable stress by dividing the allowable stress by a value obtained by dividing the first allowable load by the second allowable load. The first data is data associating the load in the out-of-plane direction applied to the flat deck when the length of the offset portion in the rib extension direction is a third length with the displacement of the flat deck in the out-of-plane direction when the load is applied. The second data is data associating the load in the out-of-plane direction applied to the flat deck when the length of the offset portion in the rib extension direction is a fourth length longer than the third length with the displacement of the flat deck in the out-of-plane direction when the load is applied.

[0016] (8): The calculation method in (7) may further include a third calculation step of calculating a division value, which is a value obtained by dividing a value obtained by subtracting the second allowable load from the first allowable load by a first natural number N1 (N1≥2), and then calculating a first value by multiplying the division value by a second natural number N2 (1≤N2<N1) and adding the second allowable load thereto.

[0017] (9): The calculation method of (8) may further include a fourth calculation step of calculating a linear function based on the first allowable load, the displacement corresponding to the first allowable load, the second allowable load, and the displacement corresponding to the second allowable load, and calculating a second value by substituting the first value into the linear function.

[0018] (10): A calculation program of the present invention is a calculation program that causes a calculation device to execute calculations for performing calculations related to a flat deck, wherein the flat deck comprises a flat surface for pouring concrete, a plurality of ribs that protrude from the flat surface in an out-of-plane direction and extend in an in-plane direction of the flat deck, and end-closed portions that extend from both end portions of the flat deck in a rib extension direction in which the ribs extend over a first length in the rib extension direction, and the end-closed portions include overhanging portions that extend over a second length from the end portions of the flat deck in the rib extension direction and are placed on beams, and offset portions that are between the overhanging portions and the ribs in the rib extension direction, and the calculation program is a memory that stores first data and second data for each type of the flat deck that are determined by an allowable stress, a plate thickness of the flat deck, and a height of the ribs in the out-of-plane direction. a first calculation step of calculating a first allowable load of the flat deck based on the first data and calculating a second allowable load of the flat deck based on the second data; and a second calculation step of calculating a design allowable stress by dividing the allowable stress by a value obtained by dividing the first allowable load by the second allowable load, wherein the first data is data correlating a load in the out-of-plane direction applied to the flat deck when the length of the offset portion in the rib extension direction is a third length with a displacement of the flat deck in the out-of-plane direction when the load is applied, and the second data is data correlating a load in the out-of-plane direction applied to the flat deck when the length of the offset portion in the rib extension direction is a fourth length longer than the third length with a displacement of the flat deck in the out-of-plane direction when the load is applied.

[0019] (11): The arithmetic program of (10) may further execute a third arithmetic step of calculating a first value by adding the second allowable load to a value obtained by multiplying a section value, which is a value obtained by dividing a value obtained by subtracting the second allowable load from the first allowable load by a first natural number N1 (N1 ≥ 2), by a second natural number N2 (1 ≤ N2 < N1).

[0020] (12): The arithmetic program of (11) may further execute a fourth arithmetic step of calculating a second value by calculating a linear function based on the first allowable load, the displacement corresponding to the first allowable load, the second allowable load, and the displacement corresponding to the second allowable load, and substituting the first value into the linear function.

Effect of the Invention

[0021] According to the present invention, there are provided an arithmetic device, an arithmetic method, and an arithmetic program that can improve the construction efficiency and reduce the construction cost of a placing slab method or a precast RC beam or the like.

Brief Description of the Drawings

[0022] [Figure 1] It is a side view showing an example of a flat deck according to an embodiment of the present invention. [Figure 2] It is a side view showing one end portion and its vicinity of a flat deck in a state where the flat deck shown in FIG. 1 is spanned over a beam. [Figure 3] It is a cross-sectional view of the flat deck taken along line A-A of FIG. 1. [Figure 4] It is a view showing a cross-section of a structure constituted by a placing slab method using the flat deck shown in FIG. 1. [Figure 5] It is a flowchart showing an arithmetic method according to an embodiment of the present invention. [Figure 6] It is a block diagram showing an example of a functional configuration of an arithmetic device according to an embodiment of the present invention. [Figure 7] It is a view showing an outline of a two-point loading test. [Figure 8] FIG. 1 is a diagram for explaining a first aspect of a two-point load test. [Figure 9] FIG. 10 is a diagram for explaining a second aspect of the two-point load test. [Figure 10] FIG. 2 is a diagram illustrating a concept of part of data stored in a storage unit. DETAILED DESCRIPTION OF THE INVENTION

[0023] Below, embodiments for implementing a computing device, a computing method, and a computing program according to the present invention are illustrated with the accompanying drawings. The embodiments illustrated below are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified or improved from the following embodiments without departing from the spirit of the present invention. In addition, in the accompanying drawings, the dimensions of each component may be exaggerated or reduced, and hatching may be omitted, in order to facilitate understanding.

[0024] 1 is a side view showing an example of a flat deck 1 according to an embodiment. As shown in FIG.

[0025] FIG. 2 is a side view showing one end of the flat deck 1 in the first direction X and its vicinity when the flat deck 1 is spanned across the beams 101. As shown in FIG. 2, the flat deck 1 is spanned across the beams 101 by placing both end portions in the first direction X and their vicinity on the beams 101, 101 provided on one side and the other side in the first direction X. The beams 101 may be underground beams or PC (prestressed concrete) beams, and in this embodiment, the beams 101 are underground beams. Therefore, the flat deck 1 is used as a formwork for pouring concrete used in the laid slab construction method, that is, as the above-mentioned "deck plate for laid slab, etc."

[0026] 1, the flat deck 1 extends in the first direction X over a length DL (hereinafter referred to as "span DL") in the first direction X. The span DL of the flat deck 1 may be, for example, about 1.5 m to 3.6 m.

[0027] Figure 3 is a cross-sectional view of the flat deck 1 taken along line A-A in Figure 1. The flat deck 1 may be formed by bending a single steel plate. As shown in Figures 1 and 3, the flat deck 1 has a flat surface 2, a plurality of ribs 3, and a plurality of end-closed portions 4,4.

[0028] The flat surface 2 is a flat surface extending in a first direction X and a second direction Y perpendicular to the first direction X. That is, the first direction X and the second direction Y each form an in-plane direction of the flat surface 2.

[0029] The rib 3 protrudes from the flat surface 2 in an out-of-plane direction of the flat surface 2 and extends in a first direction X, which is one of the in-plane directions. Therefore, the first direction X is the "rib extension direction" in which the rib 3 extends. The out-of-plane direction is a direction perpendicular to the in-plane direction, and in this embodiment, it is a third direction Z perpendicular to the first direction X and the second direction Y. When the flat deck 1 is spanned across the beams 101, 101, the third direction Z corresponds to the vertical direction, and the rib 3 protrudes from the flat surface 2 downward in the vertical direction. The rib 3 includes a first portion 3A and a second portion 3B. The first portion 3A is connected to the flat surface 2, and two steel plates bent to form the rib 3 are overlapping and extend linearly. The second portion 3B is connected to the first portion 3A and has an isosceles triangular cross section with the connection with the first portion 3A as its vertex.

[0030] As shown in Figures 2 and 3, the length of the flat surface 2 in the third direction Z is the plate thickness 2T of the flat deck 1. There are no particular limitations on the plate thickness 2T, and it may be, for example, 0.7 mm, 0.8 mm, 1.2 mm, or 1.6 mm. The length (height) of the rib 3 in the third direction Z (out-of-plane direction) is the rib height 3H. There are no particular limitations on the rib height 3H, and it may be, for example, 75 mm or 100 mm.

[0031] In this specification, the type of flat deck 1 is defined by the plate thickness 2T and the rib height 3H. For example, the type of flat deck 1 may be defined as follows: Type I is a flat deck 1 with a plate thickness 2T of 0.7 mm and a rib height 3H of 100 mm; Type II is a flat deck 1 with a plate thickness 2T of 0.8 mm and a rib height 3H of 100 mm; Type III is a flat deck 1 with a plate thickness 2T of 1.2 mm and a rib height 3H of 100 mm; Type IV is a flat deck 1 with a plate thickness 2T of 1.6 mm and a rib height 3H of 100 mm; Type V is a flat deck 1 with a plate thickness 2T of 0.7 mm and a rib height 3H of 75 mm; Type VI is a flat deck 1 with a plate thickness 2T of 0.8 mm and a rib height 3H of 75 mm; etc.

[0032] 1, multiple end-closed sections 4, 4 are formed on and near both ends of the flat deck 1 in the first direction X. The end-closed sections 4 are formed by folding predetermined portions of the steel plate that forms the flat deck 1 into a flat shape.

[0033] 2, the closed-end section 4 extends from an end of the flat deck 1 in the first direction X over a first length EL in the first direction X. Specifically, the closed-end section 4 extends from both ends of the flat deck 1 on extensions of the ribs 3 to the ends of the ribs 3. Therefore, the end of the flat deck 1 in the first direction X includes the end of the closed-end section 4 on the opposite side to the rib 3 in the first direction X.

[0034] The end-closed portion 4 includes an overlap portion 41 and an offset portion 42 .

[0035] The overlap portion 41 is a portion of the end-closed section 4 that rests on the beam 101. Therefore, the length ELa (second length) of the overlap portion 41 in the first direction X is equal to the overlap portion, which is the length in the first direction X of the portion of the flat deck 1 that rests on the beam 101 (the end in the first direction X and its vicinity). In other words, the overlap portion 41 extends over the second length ELa from the end of the flat deck 1 in the first direction X and is placed on the beam 101. For example, stirrups 102 protrude upward from the top surface 101T of the beam 101, which is an underground beam. The end of the overlap portion 41 opposite the rib 3 side (i.e., the end in the first direction X of the flat deck 1) may be adjacent to the stirrup 102, or a beam side protrusion of about 30 mm is provided to avoid adjacent to the stirrup 102 and take into account the loss of the beam cross section due to the swallowing of the deck plate, and the overlap portion 41 is placed on the beam 101 at these parts, so that the length ELa (second length) of the overlap portion 41 in the first direction X is about 30 mm.

[0036] The offset portion 42 is a portion of the end-closed section 4 located between the overlap portion 41 and the rib 3 in the first direction X. When the flat deck 1 is spanned across the beams 101, the offset portion 42 is a thin portion (having a small length in the third direction Z) located between the overlap portion 41 placed on the beam 101 and the rib 3, which has a large length (height) in the third direction Z. Therefore, stress tends to concentrate in the offset portion 42. Therefore, from the viewpoint of preventing local buckling due to stress concentration in the offset portion 42, the length ELb of the offset portion 42 in the first direction X is usually set to 40 mm or less (third length). However, in the flat deck 1 of this embodiment, the length ELb of the offset portion 42 is adjusted to a fourth length longer than the third length and the span DL is shorter than usual, based on data obtained by a calculation device 10 (see FIG. 6) and a calculation method CM (see FIG. 5), which will be described later. For example, it may be 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, or 110 mm.

[0037] FIG. 4 is a diagram showing a cross section of a structure 100 constructed using a slab-laying method using a flat deck 1. As shown in FIG. 4, the structure 100 includes a flat deck 1 (a deck plate for a slab-laying method, etc.), beams 101, 101 across which the flat deck 1 is spanned, and an RC slab 105 formed by concrete 103 poured on the flat deck 1. The RC slab 105 and the beams 101, 101 are integrated with reinforcement bars 104 and stirrups 102. The reinforcement bars 104 are disposed in the concrete 103 to increase the rigidity and strength of the RC slab 105. As described above, the structure 100 is configured so that the length ELb of the offset portion 42 of the flat deck 1 is a fourth length that is longer than the third length, which is the normal length. Such a structure 100 may be constructed by placing both ends of the flat deck 1, including the overhanging portion 41, on underground beams 101, 101, bridging the flat deck 1 across the beams 101, 101, and then using the flat deck 1 as a formwork to pour concrete 103 onto the flat surface 2 of the flat deck 1.

[0038] As described above, the flat deck 1 of this embodiment includes a flat surface 2 for pouring concrete 103, a plurality of ribs 3 that protrude from the flat surface 2 in an out-of-plane direction (third direction Z) of the flat surface 2 and extend in an in-plane direction (first direction X) of the flat surface 2, and end-closed portions 4 that extend a first length in the rib extension direction (first direction X) from each of both end portions of the flat deck 1 in the rib extension direction (first direction X) in which the ribs 3 extend. The end-closed portions 4 of the flat deck 1 include overhanging portions 41 that extend a second length from the end portions of the flat deck 1 in the rib extension direction (first direction X) and are placed on the beams 101, and offset portions 42 that are located between the overhanging portions 41 and the ribs 3 in the rib extension direction (first direction X).

[0039] The following describes the calculation device 10 and calculation method CM for performing calculations related to the flat deck 1. The calculation device 10 and calculation method CM make it possible to configure the structure 100 by setting the length ELb of the offset portion 42 of the flat deck 1 to a fourth length that is longer than the third length, rather than the third length (normal length).

[0040] Fig. 5 is a flow diagram showing the calculation method CM. The calculation method CM is a method of performing calculations for use in a flat deck laying slab construction method, for example, using a calculation device 10. As shown in Fig. 5, the calculation method CM includes a storage step ST1, a first calculation step ST2, a second calculation step ST3, a third calculation step ST4, and a fourth calculation step ST5.

[0041] Fig. 6 is a block diagram showing an example of the functional configuration of the arithmetic device 10. The arithmetic device 10 is configured by, for example, a computer including a CPU (Central Processing Unit), a memory, and an interface. As shown in Fig. 6, the arithmetic device 10 includes, as main functional blocks, a control unit 11, an input unit 12, a storage unit 13, a display unit 14, and various arithmetic units (a first arithmetic unit 15, a second arithmetic unit 16, a third arithmetic unit 17, and a fourth arithmetic unit 18), and these functional blocks may be configured to be able to transfer data between each other via a bus.

[0042] The control unit 11 is a CPU that controls the entire calculation device 10 and executes various processes. For example, when the control unit 11 receives an electrical signal from the input unit 12, it reads data stored in the memory unit 13 in response to the electrical signal, causes the various calculation units (first calculation unit 15, second calculation unit 16, third calculation unit 17, and fourth calculation unit 18) to perform predetermined calculations, and displays data obtained by the calculations performed by the various calculation units on the display unit 14. Furthermore, when information regarding the type of flat deck 1 (plate thickness 2T and rib height 3H) is input via the input unit 12, the control unit 11 may determine the type of flat deck 1 and cause each of the first calculation unit 15, second calculation unit 16, third calculation unit 17, and fourth calculation unit 18 to extract data corresponding to the input type of flat deck from the memory unit 13.

[0043] The input unit 12 is an input means such as a keyboard or a mouse. A user of the calculation device 10 may use the input unit 12 to input information for the calculations to be performed by the various calculation units. This information may include, for example, the numerical value of the plate thickness 2T and the numerical value of the rib height 3H, which are information relating to the above-mentioned type of flat deck 1. The user of the calculation device 10 may then cause the calculation device 10 to perform various calculations by pressing, for example, an execute key on the input unit 12.

[0044] The display unit 14 may be, for example, a display capable of displaying various information. The display unit 14 may display, for example, the above-mentioned information (e.g., the numerical value of the plate thickness 2T and the numerical value of the rib height 3H) input to the calculation device 10 via the input unit 12 and data obtained by calculation by the calculation device 10, which will be described later.

[0045] The storage unit 13 includes a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The storage unit 13 stores various data and calculation programs necessary for the calculation device 10 to execute calculations. The various calculation programs include, for example, programs that cause the storage unit 13 to store various data and programs that cause the first calculation unit 15, the second calculation unit 16, the third calculation unit 17, and the fourth calculation unit 18 to perform calculations. The various data also include data on allowable stress levels, and data on the first data Da1, the second data Da2, and the linear function LF shown in FIG. 10 (described later) for each type of flat deck 1.

[0046] The first data Da1 is data that associates the load in the third direction Z (out-of-plane direction) that is applied to the flat deck 1 when the length ELb of the offset portion 42 in the first direction X (rib extension direction) is the third length (a predetermined length of 40 mm or less), with the displacement of the flat deck 1 in the third direction Z when the load is applied. Hereinafter, the case where the flat deck 1 is spanned across the beams 101, 101 so that the length ELb of the offset portion 42 is the third length may be simply described as "the flat deck 1 is spanned at the third length," etc.

[0047] The second data Da2 is data that associates the load in the third direction Z (out-of-plane direction) applied to the flat deck 1 when the length of the offset portion 42 in the first direction X (rib extension direction) is a fourth length (for example, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, and 110 mm) that is longer than the third length, with the displacement of the flat deck 1 in the third direction Z when the load is applied. Hereinafter, the case where the flat deck 1 is spanned across the beams 101, 101 so that the length ELb of the offset portion 42 is the fourth length may be simply described as "the flat deck 1 is spanned at the fourth length," etc.

[0048] The first data Da1 and the second data Da2 can be obtained, for example, by a two-point loading test shown in Fig. 7. Specifically, as shown in Fig. 7, the overlapping portions 41, 41 of each type of flat deck 1 are placed on a pair of mounting bases 90, 90, and each type of flat deck 1 is placed across the pair of mounting bases 90, 90. Next, a load P is applied to loading portions 2w, 2w of the flat surface 2 located at a distance d from both ends of the flat deck 1 in the first direction X, and the displacement δ of the flat deck 1 in the third direction Z is measured. The displacement δ may be a value obtained by subtracting the position in the third direction Z of the most recessed part of the flat surface 2 when the load P is applied from the position in the third direction Z of the flat surface 2 when the load P is not applied.

[0049] The first data Da1 is obtained by adjusting the length ELa of the overlap portion 41 so that the flat deck 1 is spanned at a third length, as shown in Fig. 8. For example, the first data Da1 is obtained by applying a load P under the condition that the length EL of the end-closed portion 4 is 90 mm, the length ELa of the overlap portion 41 is 50 mm, and the length ELb of the offset portion 42 is 40 mm.

[0050] The second data Da2 is obtained by adjusting the length ELa of the overlap portion 41 so that the flat deck 1 is spanned at a fourth length, as shown in Fig. 9. For example, the second data Da2 is obtained by applying the load P under the condition that the length EL of the end-closed portion 4 is 120 mm, the length ELa of the overlap portion 41 is 10 mm, and the length ELb of the offset portion 42 is 110 mm.

[0051] Fig. 10 shows a concept of some of the data stored in the storage unit 13. As shown in Fig. 10, the storage unit 13 stores first data Da1 and second data Da2, and the first data Da1 and second data Da2 are each represented by a roughly curved graph with the displacement δ on the horizontal axis and the load P on the vertical axis. In Fig. 10, for convenience, the first data Da1 is shown by a solid line, and the second data Da2 is shown by a dashed line.

[0052] The first data Da1 is data when the flat deck 1 is spanned at the third length; in other words, data when the length ELb of the offset portion 42 is the minimum length. As shown in FIG. 10 , the first data Da1 indicates that the load P increases until the displacement δ becomes Ominδ, and when the displacement δ becomes Ominδ, the load P reaches a maximum value OminPmax. However, once the displacement δ exceeds Ominδ, the load P does not increase any further. This first data Da1 indicates that when the flat deck 1 is spanned at the third length, the flat deck 1 does not substantially undergo plastic deformation up to the load OminPmax (in other words, when the load P exceeds the load OminPmax, the flat deck 1 substantially undergoes plastic deformation). Therefore, the load OminPmax is the allowable load of the flat deck 1 when the flat deck 1 is spanned at the third length, and may be referred to as the "first allowable load P1" hereinafter. The allowable load generally refers to the maximum load that a structure, machine, etc. can support.

[0053] The second data Da2 is data when the flat deck 1 is spanned at the fourth length; in other words, data when the length ELb of the offset portion 42 is at its maximum. As shown in FIG. 10, the second data Da2 indicates that the load P increases until the displacement δ is Omaxδ, and when the displacement δ is Omaxδ, the load P reaches its maximum value OmaxPmax. However, once the displacement δ exceeds the displacement Omaxδ, the load P does not increase any further. This second data Da2 indicates that when the flat deck 1 is spanned at the fourth length, the flat deck 1 does not substantially undergo plastic deformation up to the load OmaxPmax (in other words, when the load P exceeds the load OmaxPmax, the flat deck 1 substantially undergoes plastic deformation). Therefore, the load OmaxPmax is the allowable load of the flat deck 1 when the flat deck 1 is spanned at the fourth length, and may hereinafter be referred to as the "second allowable load P2."

[0054] As shown in FIG. 10, the displacement Omaxδ forming the second data Da2 is larger than the displacement Ominδ forming the first data Da1, and the load OmaxPmax forming the second data Da2 is smaller than the load OminPmax forming the first data Da1. The allowable stress level means the maximum value of stress that the flat deck 1 can safely withstand, and is a value specific to the material forming the flat deck 1. The allowable stress level of the flat deck 1 is, for example, 235 (N / mm 2 )

[0055] In this way, the memory unit 13 of the calculation device 10 stores data on the allowable stress level, and the first data Da1 and second data Da2 for each type of flat deck 1. The storage step ST1 in the calculation method CM is a step in which the memory unit 13 of the calculation device 10 stores data on the allowable stress level, and the first data Da1 and second data Da2 for each type of flat deck 1 via the above-mentioned calculation program.

[0056] Each of the first calculation unit 15, the second calculation unit 16, the third calculation unit 17, and the fourth calculation unit 18 may include, for example, a microprocessor or a DSP (Digital Signal Processor). Each of the first calculation unit 15, the second calculation unit 16, the third calculation unit 17, and the fourth calculation unit 18 is realized by the cooperation of the hardware resources constituting the calculation device 10 with basic software, which is application software pre-installed in the calculation device 10, and various other software (for example, various software including calculation programs executed by each of the first calculation unit 15, the second calculation unit 16, the third calculation unit 17, and the fourth calculation unit 18). Examples of the hardware resources constituting the calculation device 10 include a CPU constituting the control unit 11, a ROM and RAM constituting the memory unit 13, a keyboard constituting the input unit 12, and a display constituting the display unit 14.

[0057] The first calculation unit 15 executes the following calculations under the control of the control unit 11.

[0058] First, the first calculation unit 15 reads out the first data Da1 and the second data Da2 relating to the type of the flat deck 1 inputted via the input unit 12 from the storage unit 13 based on a command from the control unit 11.

[0059] Next, the first calculation unit 15 calculates (calculates) a first allowable load P1 for the type of flat deck 1 input via the input unit 12 based on the first data Da1 read out from the memory unit 13. In addition, the first calculation unit 15 calculates (calculates) a second allowable load P2 for the type of flat deck 1 input via the input unit 12 based on the second data Da2 read out from the memory unit 13.

[0060] The control unit 11 may cause the first calculation unit 15 to store the calculated data of the first allowable load P1 and the second allowable load P2 in the storage unit 13.

[0061] In this way, the first calculation unit 15 of the calculation device 10 calculates the first allowable load P1 of the flat deck 1 based on the first data Da1, and calculates the second allowable load P2 of the flat deck 1 based on the second data Da2. The first calculation step ST2 in the calculation method CM is a step in which the first calculation unit 15 of the calculation device 10 calculates the first allowable load P1 of the flat deck 1 based on the first data Da1, and calculates the second allowable load P2 of the flat deck 1 based on the second data Da2, via the above-mentioned calculation program.

[0062] The second calculation unit 16 executes the following calculations under the control of the control unit 11.

[0063] First, the second calculation unit 16 reads out data on the first allowable load P1 and data on the second allowable load P2 from the storage unit 13. Then, the second calculation unit 16 divides the first allowable load P1 by the second allowable load P2 to calculate the value β. That is, the second calculation unit 16 executes the following equation (1). P1 / P2=β (1) As described above, since the first allowable load P1 is greater than the second allowable load P2, the value β is greater than 1.

[0064] Next, based on a command from the control unit 11, the second arithmetic unit 16 reads out data on the allowable stress from the storage unit 13 via the input unit 12. Then, the second arithmetic unit 16 calculates a design allowable stress, which is the value obtained by dividing the read allowable stress by the value β. That is, assuming the allowable stress is fb and the design allowable stress is σ, the second arithmetic unit 16 executes the following formula (2). fb / β = σ ··· (2) As described above, since the value β is greater than 1, the design allowable stress σ is smaller than the allowable stress fb.

[0065] The control unit 11 may cause the second arithmetic unit 16 to store the value of the design allowable stress σ in the storage unit 13, or may cause the second arithmetic unit 16 to display the value of the design allowable stress σ on the display unit 14.

[0066] Thus, the second arithmetic unit 16 of the arithmetic device 10 calculates the design allowable stress σ by dividing the allowable stress fb by the value β obtained by dividing the first allowable load P1 by the second allowable load P2. And the second arithmetic step ST3 in the arithmetic method CM is a step in which the second arithmetic unit 16 of the arithmetic device 10 calculates the design allowable stress σ by dividing the allowable stress fb by the value β obtained by dividing the first allowable load P1 by the second allowable load P2 through the above-described arithmetic program.

[0067] Based on control by the control unit 11, the third arithmetic unit 17 executes the following arithmetic.

[0068] When the first natural number N1 (N1 ≥ 2) and the second natural number N2 (1 ≤ N2 < N1) are input via the input unit 12, the third arithmetic unit 17 performs the following arithmetic based on control by the control unit 11. Also, when the first natural number N1 and the second natural number N2 are input, the control unit 11 causes the first natural number N1 and the second natural number N2 to be stored in the storage unit 13.

[0069] First, based on an instruction from the control unit 11, the third calculation unit 17 reads out data on the first allowable load P1 and the second allowable load P2 relating to the type of flat deck 1 input via the input unit 12 from the memory unit 13.

[0070] Next, the third calculation unit 17 calculates a value γ obtained by subtracting the second allowable load P2 from the first allowable load P1, as shown in Fig. 10. That is, the third calculation unit 17 executes the following equation (3). P1-P2=γ (3) Then, the third calculation unit 17 reads the first natural number N1 from the storage unit 13 and calculates the division value SV by dividing the value γ by the first natural number N1. That is, the third calculation unit 17 executes the following equation (4). γ / N1=SV (4) Next, the third calculation unit 17 reads the second natural number N2 from the storage unit 13, and calculates a value ε by multiplying the division value SV by the second natural number N2. That is, the third calculation unit 17 executes the following equation (5). SV×N2=ε (5) Next, the third calculation unit 17 adds the second allowable load P2 to the value ε to calculate the first value OxPmax. That is, the third calculation unit 17 executes the following equation (6). ε+P2=OxPmax (6) This first value OxPmax is a load that is smaller than the first allowable load P1 and larger than the second allowable load P2.

[0071] The control unit 11 may cause the third calculation unit 17 to store the first value OxPmax in the memory unit 13, and may cause the third calculation unit 17 to display the first value OxPmax on the display unit 14.

[0072] Thus, the third calculation unit 17 of the arithmetic unit 10 calculates a section value SV, which is a value obtained by dividing a value γ obtained by subtracting the second allowable load P2 from the first allowable load P1 by a first natural number N1 (N1 ≥ 2). After that, the third calculation unit 17 multiplies the section value SV by a second natural number N2 (1 ≤ N2 < N1) to obtain a value ε, and then adds the second allowable load P2 to the value ε to calculate a first value OxPmax. Then, the third calculation step ST4 in the calculation method CM is a step in which the third calculation unit 17 of the arithmetic unit 10 calculates a section value SV, which is a value obtained by dividing a value γ obtained by subtracting the second allowable load P2 from the first allowable load P1 by a first natural number N1 (N1 ≥ 2), through the above calculation program. After that, the third calculation unit 17 multiplies the section value SV by a second natural number N2 (1 ≤ N2 < N1) to obtain a value ε, and then adds the second allowable load P2 to the value ε to calculate a first value OxPmax.

[0073] Based on the control by the control unit 11, the fourth calculation unit 18 executes the following calculation.

[0074] First, based on a command from the control unit 11, the fourth calculation unit 18 reads out first data Da1 and second data Da2 regarding the type of the flat deck 1 input via the input unit 12 from the storage unit 13.

[0075] Here, paying attention to the first data Da1 shown in FIG. 10, the displacement δ corresponding to the first allowable load P1 is Ominδ. Also, paying attention to the second data Da2 shown in FIG. 10, the displacement δ corresponding to the second allowable load P2 is Omaxδ. The fourth calculation unit 18 calculates a linear function LF defined by the load P and the displacement δ based on the first allowable load P1, the displacement Ominδ, the second allowable load P2, and the displacement Omaxδ. That is, when Ominδ is represented as δ1 and Omaxδ is represented as δ2, the third calculation unit 17 calculates a linear function LF represented by the following formula (7). P = -{(P1 - P2) / (δ2 - δ1)}δ + P1 + {(P1 - P2) / (δ2 - δ1)}δ1 ··· (7) This linear function LF is represented by a dashed line in FIG. 10 for convenience.

[0076] Next, the fourth calculation unit 18 reads out the first value OxPmax stored in the storage unit 13 from the storage unit 13, and calculates the displacement Oxδ (second value) by substituting the first value OxPmax into the linear function LF.

[0077] The control unit 11 may cause the fourth calculation unit 18 to store the displacement Oxδ (second value) in the memory unit 13, and may also cause the fourth calculation unit 18 to display the displacement Oxδ (second value) on the display unit 14.

[0078] In this way, the fourth calculation unit 18 of the calculation device 10 calculates the linear function LF based on the first allowable load P1, the displacement δ1 corresponding to the first allowable load P1, the second allowable load P2, and the displacement δ2 corresponding to the second allowable load P2, and calculates the displacement Oxδ (the second value) by substituting the first value OxPmax into the linear function LF. Then, the fourth calculation step ST5 in the calculation method CM is a step in which the fourth calculation unit 18 of the calculation device 10 calculates the linear function LF based on the first allowable load P1, the displacement δ1 corresponding to the first allowable load P1, the second allowable load P2, and the displacement δ2 corresponding to the second allowable load P2, via the above-mentioned calculation program, and calculates the displacement Oxδ (the second value) by substituting the first value OxPmax into the linear function LF.

[0079] As described above, the calculation device 10 of this embodiment is equipped with a first calculation unit 15, a second calculation unit 16, and a memory unit 13 that stores first data Da1 and second data Da2 for each type of flat deck 1 determined by the allowable stress fb, the plate thickness 2T of the flat deck 1, and the rib height 3H of the rib 3 in the out-of-plane direction (third direction Z).In the calculation device 10, the first calculation unit 15 calculates the first allowable load P1 of the flat deck 1 based on the first data Da1, and calculates the second allowable load P2 of the flat deck 1 based on the second data Da2, and the second calculation unit 16 calculates the design allowable stress σ by dividing the allowable stress fb by the value β obtained by dividing the first allowable load P1 by the second allowable load P2.

[0080] The calculation method CM of this embodiment also includes a storage step ST1 for storing first data Da1 and second data Da2 for each type of flat deck 1, which are determined by the allowable stress fb, the plate thickness 2T of the flat deck 1, and the rib height 3H of the rib 3 in the out-of-plane direction; a first calculation step ST2 for calculating a first allowable load P1 of the flat deck 1 based on the first data Da1 and a second allowable load P2 of the flat deck 1 based on the second data Da2; and a second calculation step ST3 for calculating a design allowable stress σ by dividing the allowable stress fb by a value β obtained by dividing the first allowable load P1 by the second allowable load P2. The calculation program of this embodiment causes the calculation device 10 to execute the storage step ST1, the first calculation step ST2, and the second calculation step ST3.

[0081] However, when the flat deck 1 is laid at the fourth length, the length ELb of the offset portion 42 is long, so the flat deck 1 is more likely to be displaced (bend) and plastically deform than when the flat deck 1 is laid at the third length. Therefore, when the flat deck 1 is laid at the fourth length based on the allowable stress fb, there is a risk that the strength and rigidity required for a deck plate for a laid slab, etc. will not be met.

[0082] However, as described above, according to the calculation device 10, calculation method CM, and calculation program of this embodiment, the first calculation unit 15 (first calculation step ST2) and the second calculation unit 16 (second calculation step ST3) calculate the value β, thereby calculating a design allowable stress σ that is smaller than the allowable stress fb. This design allowable stress σ is calculated based on the value β (i.e., the ratio of the first allowable load P1 to the second allowable load P2) obtained by dividing the first allowable load P1 for normal use when the length ELb of the offset portion 42 is the minimum third length (e.g., 40 mm) by the second allowable load P2 for normal use when the length ELb of the offset portion 42 is the maximum fourth length (e.g., 110 mm). Therefore, by adjusting the flat deck 1 so that the design allowable stress σ is not exceeded, the flat deck 1 can be used as a deck plate for a slab or the like, even when the length ELb of the offset portion 42 is longer than the third length. Specifically, by shortening the span DL (see Figure 1) of the flat deck 1 compared to when the flat deck 1 is spanned at the third length so as not to exceed the design allowable stress σ, the flat deck 1 can be used as a deck plate for a slab, etc., even if the length ELb of the offset portion 42 is made longer than the third length.

[0083] Therefore, according to the calculation device 10, calculation method CM, and calculation program of this embodiment, it is possible to eliminate the need to use a custom-made product in which the length EL of the end-closed section 4 is shorter than that of a normal flat deck, and a normal flat deck can be used as a deck plate for laid slabs, etc., thereby improving the construction efficiency of laid slab construction methods or precast RC beams, etc., and reducing construction costs.

[0084] As described above, the minimum value of the length ELb of the offset portion 42 may be 40 mm, and the maximum value may be 110 mm. In this case, the first data Da1 is obtained when the length ELb is 40 mm ("0" in FIG. 10). 40 The second data Da2 is the data when the length ELb is 110 mm (indicated as "O" in FIG. 10). 110In this case, as shown in FIG. 10, the first natural number N1 is set to 7, and the difference γ between the first allowable load P1 of the first data Da1 and the second allowable load P2 of the second data Da2 is divided by the first natural number N1 to calculate the division value SV, and the value obtained by adding the division value SV to the second allowable load P2 is the value obtained when the length ELb is 100 mm (in FIG. 10, "0 100 " is displayed.) This is the value that can be estimated as the allowable load OxPmax.

[0085] Also, as shown in Figure 10, the value obtained by adding twice the division value SV to the second allowable load P2 is 90 "). Similarly, the value obtained by adding three times the division value SV to the second allowable load P2 is the value that can be estimated as the allowable load OxPmax when the length ELb is 80 mm (indicated as "OxPmax" in Figure 10). 80 The value obtained by adding four times the division value SV to the second allowable load P2 is the value that can be estimated as the allowable load OxPmax when the length ELb is 70 mm (indicated as "O 70 The value obtained by adding five times the division value SV to the second allowable load P2 is the value that can be estimated as the allowable load OxPmax when the length ELb is 60 mm (indicated as "O 60 The value obtained by adding six times the division value SV to the second allowable load P2 is the value that can be estimated as the allowable load OxPmax when the length ELb is 50 mm (indicated as "O 50 " is displayed.) This is the value that can be estimated as the allowable load OxPmax.

[0086] As described above, the third calculation unit 17 calculates a section value SV, which is a value obtained by dividing a value γ obtained by subtracting the second allowable load P2 from the first allowable load P1 by a first natural number N1 (N1 ≥ 2). After that, the third calculation unit 17 adds the second allowable load P2 to a value ε obtained by multiplying the section value SV by a second natural number N2 (1 ≤ N2 < N1) to calculate a first value OxPmax. Then, in the third calculation step ST4 in the calculation method CM, the third calculation unit 17 of the calculation device 10 calculates a section value SV, which is a value obtained by dividing a value γ obtained by subtracting the second allowable load P2 from the first allowable load P1 by a first natural number N1 (N1 ≥ 2), through the above calculation program. After that, the third calculation unit 17 adds the second allowable load P2 to a value ε obtained by multiplying the section value SV by a second natural number N2 (1 ≤ N2 < N1) to calculate a first value OxPmax. Therefore, according to the present embodiment, even when the second data Da2 when the length ELb is 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm is not stored, the third calculation unit 17 and the third calculation step ST4 can estimate the allowable load OxPmax when the length ELb is 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm.

[0087] Also, in the present embodiment, the calculation device 10 includes a fourth calculation unit 18, and the calculation method CM includes a fourth calculation step ST5. Therefore, according to the present embodiment, even when the second data Da2 when the length ELb is 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm is not stored, in the fourth calculation unit 18 (the fourth calculation step ST5), by substituting the allowable load OxPmax estimated in the third calculation unit 17 (the third calculation step ST4) into the linear function LF, the displacement Oxδ (the second value) corresponding to the allowable load OxPmax in each case where the length ELb is 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm can be estimated.

[0088] As described above, the present invention has been described by taking the above-described embodiment as an example, but the present invention is not limited thereto.

[0089] For example, in the above-described embodiment, an example in which the fourth length is 110 mm has been described, but the fourth length can be changed as appropriate as long as it is a length greater than 40 mm. Also, in the above-described embodiment, an example in which the third length is 40 mm has been described, but the third length can be changed as appropriate as long as it is 40 mm or less. Also, in the above-described embodiment, an example in which the first natural number N1 is 7 has been described, but the first natural number N1 can be changed as appropriate as long as it is 2 or greater.

[0090] In the above-described embodiment, an example was described in which the calculation device 10 includes the third calculation unit 17 and the fourth calculation unit 18, and the calculation method CM includes the third calculation step ST4 and the fourth calculation step ST5. However, if data on the allowable load OxPmax and the displacement Oxδ when the length ELb is, for example, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm, are stored in the storage unit 13, the data on the allowable load OxPmax and the data on the displacement Oxδ when the length ELb is, for example, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm can be obtained by reading the data in the storage unit 13 without performing the calculations performed by the third calculation unit 17 and the fourth calculation unit 18. Therefore, in such a case, the calculation device 10 does not need to include the third calculation unit 17 and the fourth calculation unit 18, and the calculation method CM does not need to include the third calculation step ST4 and the fourth calculation step ST5.

[0091] Furthermore, those skilled in the art can appropriately modify the arithmetic device, arithmetic method, and arithmetic program according to the present invention in accordance with conventionally known knowledge. As long as such modifications still comprise the configuration of the present invention, they are of course included in the scope of the present invention. [Explanation of symbols]

[0092] 1...flat deck, 2...flat surface, 2T...plate thickness, 3...rib, 4...end-closed portion, 10...calculation device, 13...memory unit, 15...first calculation unit, 16...second calculation unit, 17...third calculation unit, 18...fourth calculation unit, 41...overlap portion, 42...offset portion, 100...structure, 101...beam, 103...concrete, 105...RC slab, CM...calculation method, Da1...first data, Da2...second data, LF...linear function, OxPmax...first value, Oxδ...second value, P1...first allowable load, P2...second allowable load, ST1...storage step, ST2...first calculation step, ST3...second calculation step, ST4...third calculation step, ST5...fourth calculation step, SV...category value

Claims

1. A computing device for performing calculations related to a flat deck, The flat deck is a flat, level surface for pouring concrete; a plurality of ribs protruding from the flat surface in an out-of-plane direction and extending in an in-plane direction of the flat surface; and an end-closed portion extending from each of both end portions of the flat deck in a rib extending direction in which the ribs extend over a first length in the rib extending direction, The end-closed portion is a contact portion extending from an end of the flat deck in the rib extension direction over a second length and placed on a beam; an offset portion located between the engagement portion and the rib in the rib extending direction, The calculation device includes a first calculation unit, a second calculation unit, and a storage unit that stores data on allowable stress, and first data and second data for each type of the flat deck determined by the plate thickness of the flat deck and the height of the rib in the out-of-plane direction, the first data is data associating a load in the out-of-plane direction applied to the flat deck when a length of the offset portion in the rib extension direction is a third length with a displacement of the flat deck in the out-of-plane direction when the load is applied, the second data is data associating a load in the out-of-plane direction applied to the flat deck when a length of the offset portion in the rib extension direction is a fourth length that is longer than the third length with a displacement of the flat deck in the out-of-plane direction when the load is applied, the first calculation unit calculates a first allowable load of the flat deck based on the first data, and calculates a second allowable load of the flat deck based on the second data, A calculation device in which the second calculation unit calculates a design allowable stress by dividing the allowable stress by a value obtained by dividing the first allowable load by the second allowable load.

2. the calculation device further includes a third calculation unit, 2. The calculation device according to claim 1, wherein the third calculation unit calculates a division value obtained by dividing the value obtained by subtracting the second allowable load from the first allowable load by a first natural number N1 (N1 > 1), and then calculates the first value by multiplying the division value by a second natural number N2 (1 ≦ N2 < N1) and adding the second allowable load to the resultant value.

3. the calculation device further includes a fourth calculation unit, 3. The calculation device according to claim 2, wherein the fourth calculation unit calculates a linear function based on the first allowable load, the displacement corresponding to the first allowable load, the second allowable load, and the displacement corresponding to the second allowable load, and calculates the second value by substituting the first value into the linear function.

4. The arithmetic device according to claim 2 or 3, wherein the first natural number N1 is 7.

5. The computing device according to claim 1 , wherein the third length is 40 mm.

6. The computing device according to claim 1 , wherein the fourth length is 110 mm.

7. A calculation method for performing calculations related to a flat deck, comprising: The flat deck is a flat, level surface for pouring concrete; a plurality of ribs protruding from the flat surface in an out-of-plane direction and extending in an in-plane direction of the flat surface; and an end-closed portion extending from each of both end portions of the flat deck in a rib extending direction in which the ribs extend over a first length in the rib extending direction, The end-closed portion is a contact portion extending from an end of the flat deck in the rib extension direction over a second length and placed on a beam; an offset portion located between the engagement portion and the rib in the rib extending direction, The calculation method includes: a storage step of storing first data and second data for each type of flat deck determined by data on allowable stress, the plate thickness of the flat deck, and the height of the rib in the out-of-plane direction; a first calculation step of calculating a first allowable load of the flat deck based on the first data and calculating a second allowable load of the flat deck based on the second data; a second calculation step of calculating a design allowable stress by dividing the allowable stress by a value obtained by dividing the first allowable load by the second allowable load; Equipped with the first data is data associating a load in the out-of-plane direction applied to the flat deck when a length of the offset portion in the rib extension direction is a third length with a displacement of the flat deck in the out-of-plane direction when the load is applied, a calculation method in which the second data is data that corresponds a load in the out-of-plane direction applied to the flat deck when the length of the offset portion in the rib extension direction is a fourth length that is longer than the third length, and a displacement of the flat deck in the out-of-plane direction when the load is applied.

8. 8. The calculation method according to claim 7, further comprising a third calculation step of calculating a division value, which is a value obtained by subtracting the second allowable load from the first allowable load and dividing the result by a first natural number N1 (N1≧2), and then multiplying the division value by a second natural number N2 (1≦N2<N1) to obtain a value, and adding the second allowable load to the obtained value to calculate a first value.

9. 9. The calculation method according to claim 8, further comprising a fourth calculation step of calculating a linear function based on the first allowable load, the displacement corresponding to the first allowable load, the second allowable load, and the displacement corresponding to the second allowable load, and calculating a second value by substituting the first value into the linear function.

10. A calculation program for causing a calculation device to perform calculations related to a flat deck, The flat deck is a flat, level surface for pouring concrete; a plurality of ribs protruding from the flat surface in an out-of-plane direction and extending in an in-plane direction of the flat surface; and an end-closed portion extending from each of both end portions of the flat deck in a rib extending direction in which the ribs extend over a first length in the rib extending direction, The end-closed portion is a contact portion extending from an end of the flat deck in the rib extension direction over a second length and placed on a beam; an offset portion located between the engagement portion and the rib in the rib extending direction, The calculation program a storage step of storing first data and second data for each type of flat deck determined by data on allowable stress, the plate thickness of the flat deck, and the height of the rib in the out-of-plane direction; a first calculation step of calculating a first allowable load of the flat deck based on the first data and calculating a second allowable load of the flat deck based on the second data; a second calculation step of calculating a design allowable stress by dividing the allowable stress by a value obtained by dividing the first allowable load by the second allowable load; Execute the first data is data associating a load in the out-of-plane direction applied to the flat deck when a length of the offset portion in the rib extension direction is a third length with a displacement of the flat deck in the out-of-plane direction when the load is applied, The second data is data that associates the load in the out-of-plane direction applied to the flat deck when the length of the offset portion in the rib extension direction is a fourth length that is longer than the third length with the displacement of the flat deck in the out-of-plane direction when the load is applied.

11. 11. The calculation program according to claim 10, further comprising a third calculation step of calculating a division value, which is a value obtained by dividing a value obtained by subtracting the second allowable load from the first allowable load by a first natural number N1 (N1≧2), and then multiplying the division value by a second natural number N2 (1≦N2<N1) and adding the second allowable load to the obtained value to calculate a first value.

12. 12. The arithmetic program according to claim 11, further comprising a fourth calculation step of calculating a linear function based on the first allowable load, the displacement corresponding to the first allowable load, the second allowable load, and the displacement corresponding to the second allowable load, and calculating a second value by substituting the first value into the linear function.

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