JP2000303609A - Equipment, method and recording medium for structural designing of hollow slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide equipment for structural designing of a hollow slab capable of thoroughly performing optimum structural design as well as a method and recording media therefor. SOLUTION: This equipment 1 for structural designing of hollow slab comprises a storage section 3 and a processing section 2 having a dividing section 20 for dividing a hollow slab into a plurality of elements depending upon the number of divisions input, a strain calculating section (strain calculating means) 21 calculating displacements and strains occurred in the hollow slab, stress calculating section (stress calculating means) 22 for calculating stresses occurred in the hollow slab, a deflection decision section (first decision means) 23 deciding the safety related to the deflection in the hollow slab, cracking decision section (second decision means) 24 for deciding the safety related to the cracking in the hollow slab, a steel bar quantity calculating section (steel bar quantity calculating means) 25 for calculating the quantity of steel bar required for the hollow slab, and a shearing force decision section (third decision means) 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for designing a hollow slab structure for use in a structural design of a reinforced concrete floor (hollow slab) having a cylindrical hollow structure, and a recording medium therefor.

[0002]

2. Description of the Related Art In general, a reinforced concrete floor panel structure is to be subjected to a fixed load or a loaded load at all times, and has an appropriate margin for an allowable limit of structural strength and use performance.
The structure is designed to ensure its safety. Also,
Conventionally, the design of a reinforced concrete floor plate structure is based on the Architectural Institute of Japan's "Reinforced Concrete Structural Calculation Standards / Comments".

[0003]

The calculations for such a structural design are made under certain assumptions, but the structural calculations based on the simplified assumptions make it possible to grasp the correct displacement and stress properties of the structure. There may not be. This is because the structural system assumed for the structural calculation cannot simulate an actual phenomenon. At present, a method of arranging voids (hollow pipe-shaped members) inside a floor slab structure has been put to practical use in a reinforced concrete floor slab structure for the purpose of weight reduction, material saving, and a large span structure without a small beam. The floor panel structure by the construction method is called a hollow slab.) However, although the structural design method and computer program for the whole building are generally known, there is not much known about the appropriate structural calculation method for hollow slabs, especially the rational structure calculation method using the finite element method considering anisotropy. Not been.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has an object to provide a hollow slab structure designing apparatus, a method thereof, and a recording medium capable of performing an optimum structural design consistently in the structural design of a hollow slab. To provide.

[0005]

According to the present invention, there is provided a hollow slab structure designing apparatus, comprising: an input unit for inputting input data used for calculating strain and stress generated in a hollow slab; and a load applied to the hollow slab. A processing unit including a strain calculating unit that calculates a displacement and a strain of the hollow slab, and a stress calculating unit that calculates a stress generated in the hollow slab based on the strain of the hollow slab calculated by the strain calculating unit. And the input data, a storage unit that stores data calculated by the processing unit, and an output unit that outputs a result calculated by the processing unit, wherein the distortion calculation unit,
{P} = [K] {δ} (where, {P}: load vector, [K]: stiffness matrix obtained by using bending stiffness matrix [D] considering orthogonal anisotropy, {δ} : Displacement vector), a load vector and a stiffness matrix are set based on the input data to calculate a displacement, and a distortion is calculated based on the calculated displacement. The stress calculating means calculates {M} = [D] {ε} (where, {M}: stress vector, [D]: bending stiffness matrix considering orthogonal anisotropy, {ε}: Using a relational expression between a stress vector and a strain vector that can be expressed by a strain vector), based on the input data and the strain calculated by the strain calculating unit,

(Equation 7)

(Equation 8) _{However, k x, k y, k} 1, k xy: coefficient considering the orthotropic, E: Young's modulus, t: a bed depth, [nu: characterized by performing the calculation of the Poisson's ratio, set the stress And

The present invention takes into account the orthogonal anisotropy of a hollow slab including voids (hollow pipe structure) arranged in one direction, and calculates stress in two directions, a parallel direction to the void and a direction perpendicular to the void. I have. Note that a direction parallel to the void is called a void parallel direction, and a direction orthogonal to the void is called a void orthogonal direction.

In the hollow slab structure designing apparatus, the strain calculating means and the stress calculating means calculate the displacement and strain according to a boundary condition for each element of the hollow slab divided into a plurality of elements. The calculation of the stress is performed. Here, the boundary condition includes a degree of fixation in consideration of bending back of the pin support / fixed support / fixed end moment. According to the present invention, displacement, strain, and stress generated in a hollow slab according to a boundary condition can be calculated.

Further, in the hollow slab structure designing apparatus, the stress calculating means uses a boundary element method to calculate a horizontal displacement d _p of a cross-sectional end of the solid slab due to a bending moment and a cross-section of the hollow slab. calculating a horizontal displacement d _y end, the value of the coefficient k _y, and calculates _{k y = d p / d y} , as.

In the hollow slab structure designing apparatus, the processing unit compares a value obtained by multiplying a maximum displacement of the hollow slab calculated by the strain calculating means by a safety factor in consideration of creep with a reference value, It is characterized by including first determining means for determining the safety of the deflection of the hollow slab.
ADVANTAGE OF THE INVENTION According to this invention, the safety regarding the bending of a hollow slab can be determined automatically.

Further, in the hollow slab structure designing apparatus,
The processing unit may include a hollow switch calculated by the stress calculator.
Maximum stress generated in the rub and Mc = k · (Fc)
^1/2Z, where k: coefficient, Fc: concrete design strength
Degree, Z: Crack moment Mc expressed by section modulus
To determine the safety of cracks in hollow slabs
It is characterized by including a second judging means for performing the judgment. In addition,
The number k is determined separately. For example, the unit of Fc is
[Kg / cm ^Two], The unit of Z is [cm^Three/ M]
Then, 1.8 is used as the value. According to the present invention,
Automatically determine the safety of cracks in empty slabs
You.

In the hollow slab structure designing apparatus, the storage unit stores a stress concentration coefficient α relating to an element shape of a reinforcing bar in a direction perpendicular to the void, and the processing unit stores a reinforcing steel amount N required for the hollow slab. And a rebar amount calculating means for calculating using the stress concentration coefficient α. ^{Specifically, N '= αM × 10 2} / (f t ja s B), however, alpha: stress concentration factor for element shapes, M: maximum value of the stress _{[tm / m], f t} : permissible rebar Tensile stress [t /
cm ^2], j: stress center distance [cm], a _s: cross-sectional area per one reinforcing bars used [cm ^2], B: unit width [c
m], the rebar amount N is calculated as a value N obtained by rounding up the decimal value of N ′ calculated as described above.

According to the present invention, the necessary amount of reinforcing bars is determined in consideration of stress concentration on the voids in the reinforcing bars arranged in the direction perpendicular to the voids. That is, calculation suitable for the structure of the hollow slab is performed. The distance between the stress centers is, for example, d × 7 /
8 (However, d is the distance between the reinforcing steel to be laid and the floor underneath)
Is set as ADVANTAGE OF THE INVENTION According to this invention, the amount of rebar required for a hollow slab can be calculated automatically. Also, by dividing the hollow slab into elements and calculating the amount of rebar required for each element,
The minimum necessary arrangement of bars can be performed.

In the hollow slab structure designing apparatus, the processing unit may be configured such that τ = Qx × (B / b) / (7/8 × (H- _dt )) with respect to the void parallel direction. ,
Τ = Qy / (7/8 × (H−
φ)), where Qx: maximum shear force in the direction parallel to the void [t / m], Qy: maximum shear force in the direction perpendicular to the void [t]
/ M], B: distance between void centers, b: distance between void outer diameters, H: floor thickness, φ: void diameter, d _t : distance from tensile edge of floor to bar center of gravity, τ And a third determination unit that compares the allowable shear stress level with the allowable shear stress level and determines safety related to a shear force generated in the hollow slab. ADVANTAGE OF THE INVENTION According to this invention, the safety | security regarding the shearing force which arises in a hollow slab can be determined automatically.

The method of designing a hollow slab structure of the present invention
In the slab with a cross section, the secondary section in the void parallel direction
Comment I_xCalculation procedure and the space without hollow section
Second moment of area I in the direction parallel to the void in the love₀
And the second moment of area I_xTo I₀so
Division factor k_xUsing the boundary element method
Slab without hollow section due to bending moment
Horizontal displacement d of the cross-sectional end of_pAnd the cross-sectional end of the hollow slab
Horizontal displacement d_yCalculating the bending mode
Section end of slab without hollow section
Horizontal displacement d of _pThe cross section of the hollow slab is horizontal
Displacement d_yDivided by k_yCalculating the
Number k_x, K_yAnd the average is taken as the coefficient k₁, K_xyWhen
{P} = [K] {δ}, (here
Where {P}: Load vector, [K]: Orthotropic
Stiffness determined using the calculated bending stiffness matrix [D]
Matrix, {δ}: Displacement vector)
Using the relational expression between torque and displacement vector, the input data
Set the load vector and stiffness matrix based on
Calculate and calculate the distortion based on the calculated displacement.
And {M} = [D] {ε}, where
{M}: stress vector, [D]: considering orthotropic
Flexural rigidity matrix, {ε}: Strain vector)
Using the relational expression between the force vector and the strain vector, the input data
Data and the distortion calculated by the distortion calculating means.
To

(Equation 9)

(Equation 10) Here, k _x , k _y , k ₁ , k _xy : a coefficient considering orthogonal anisotropy, E: longitudinal elastic modulus, t: floor thickness, ν: Poisson's ratio, and a procedure for calculating stress. It is characterized by including.

[0015] The present invention is a recording medium recording a strain stress calculation program in a hollow slab structure designing apparatus,
Section 2 in the void parallel direction in a slab having a hollow section
And procedures for calculating the next moment I _x, the procedure for calculating the second moment I ₀ of voids parallel direction in the slab without a hollow section, the second moment I _x I
Using the boundary element method and the procedure of calculating the coefficient k _x by dividing by ₀ , the horizontal displacement d _p of the cross-sectional end of the slab having no hollow section due to the bending moment and the cross-sectional end of the hollow slab a step of calculating a horizontal displacement d _y, wherein by bending moment, the horizontal displacement d _p of the cross-sectional end portion of the slab having no hollow cross-section in the horizontal displacement d _y of the cross-section end of the hollow slabs Dividing the coefficient k _y , calculating the coefficient k _x , k _y , and setting the average value as the coefficient k ₁ , k _xy , {P} = [K] {δ}, (Here, {P}: load vector, [K]: rigidity matrix obtained by using bending rigidity matrix [D] in consideration of orthogonal anisotropy, {δ}: displacement vector and displacement vector) Using the input data, the load vector And calculating a displacement by setting a rigidity matrix and calculating a strain based on the calculated displacement, {M} = [D] {ε}, (where,
{M}: stress vector, [D]: bending stiffness matrix considering orthogonal anisotropy, {ε}: strain vector), using the relational expression of stress vector and strain vector, and calculating the input data and strain. Based on the distortion calculated by the means,

[Equation 11]

(Equation 12) However, k _x , k _y , k ₁ , k _xy : a coefficient considering orthogonal anisotropy, E: longitudinal elastic modulus, t: floor thickness, ν: Poisson's ratio, and a procedure for calculating stress by computer A computer-readable recording medium storing a strain stress calculation program to be executed by a computer.

As described above, the program for realizing the functions of the hollow slab structure designing apparatus in the computer is recorded on the recording medium, and the program is read from the recording medium into the computer, so that the computer can easily design the hollow slab structure using the computer. The device can be realized.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a hollow slab structure designing apparatus according to one embodiment of the present invention.

The hollow slab structure designing apparatus 1 includes a processing unit 2 described below, a storage unit 3 for storing input data and a calculation result by the processing unit 2, and an input unit (not shown) to which input data is input. And an output unit (not shown) for outputting a calculation result by the processing unit 2. The processing unit 2 includes a dividing unit 20 that equally divides the hollow slab into a plurality of elements (rectangular elements) according to the number of divisions input to the input unit, and a distortion calculating unit that calculates displacement and distortion due to a load applied to the hollow slab. (Strain calculating unit) 21, a stress calculating unit (stress calculating unit) 22 for calculating stress generated in the hollow slab, and a bending determining unit (first determining unit) 23 for determining safety related to bending of the hollow slab. A crack determining unit (second determining unit) 24 for determining the safety of the hollow slab with respect to cracks; a reinforcing bar amount calculating unit (rebar amount calculating unit) 25 for calculating a reinforcing bar amount necessary for the hollow slab; Force determination unit (third determination means) for determining the safety related to the shear force generated in the vehicle (third determination means) 26
It is composed of

The processing unit 2 includes a memory, a CPU (Central Processing Unit), and the like. A program (not shown) for realizing each function of the processing unit 2 is loaded into the memory and executed to execute the program. The function shall be realized. The storage unit 3 is configured by a storage device such as a memory, a hard disk, and a magneto-optical disk. The input unit uses an input device such as a keyboard and a mouse. The output part is a CRT (Cathode Ray Tub)
e) or an output device such as a liquid crystal display device or a printer.

First, the hollow slab whose structural design is to be performed by the hollow slab structure designing apparatus 1 of the present embodiment and the force acting on the hollow slab will be described. FIG. 2 shows the structure of the hollow slab and the forces acting on it. The hollow slab structure designing apparatus 1 targets a slab in which the voids shown in FIG. In this hollow slab,
As shown in the figure, a stress is generated that includes bending moments: Mx and My and shear forces: Qx and Qy. The hollow slab structure design apparatus 1 takes into consideration these forces and the structure specific to the hollow slab, and inputs materials (reinforcing bar, concrete), loads, dimensions, the number of divisions, and the like necessary for the hollow slab used for the building to be designed. By doing, the displacement, distortion,
It automatically calculates and outputs stress (bending moment, shear force, reaction force) and the like.

Next, an outline of the operation of the hollow slab structure designing apparatus 1 configured as described above will be described, and details thereof will be described later. Upon receiving input of predetermined input data, the hollow slab structure designing apparatus 1 of the present embodiment first calculates displacement / strain as shown in the operation flowchart of FIG. 36 (Step S0). Then, stress is calculated using the strain data calculated in step S0 (step S1).
Further, in response to a request of the user (designer), the safety of flexure is determined (step S2), the safety of bending and cracking is determined (step S3), and the required amount of rebar is calculated (step S2).
4), the shear force safety is determined (step S5).

Next, the operation of the hollow slab structure designing apparatus 1 will be described in detail. First, from the input unit (not shown),
Concrete design strength Fc to be analysis conditions (see FIG. 3)
[Kg / cm ² ], reinforcing bar design strength Fs [kg / cm ² ],
Floor thickness H [mm], void diameter [mm], cover thickness [mm], concrete specific gravity [kg / cm ³ ], finishing load [kg / m ² ], Poisson's ratio ν (for ordinary concrete: 1 / 6), short side length [mm], long side length [m
m], data such as separately determined loading load, concentrated load, linear load (depending on walls, etc.), and boundary conditions for the degree of fixation considering the pin support, fixed support, and return of fixed end moment (see Fig. 5) Is entered. Furthermore, the number of divisions corresponding to the short side and the long side of the floor is input so that when the model of the hollow slab to be structurally designed is divided into a plurality of elements, each element becomes substantially square. In FIG. 3, the floor thickness is 4
An example is shown in which 00 [mm], the void diameter is 250 [mm], the cover thickness is 75 [mm], and the distance between void centers is 400 [mm]. In addition, as the fixing degree in consideration of the bending back of the fixed end moment, which is one of the boundary conditions, a value from a fixing degree of 100% assuming the fixed end to a fixing degree of 0% assuming the pin end can be set. It is.

The numerical examples shown in the figures referred to in the following description are based on these values as the analysis conditions, concrete design strength Fc = 210 [kg / cm ² ], concrete Poisson's ratio ν = 1/1. 6. Rebar design strength Fs = 20
00 [kg / cm ² ], short side length 4248 [mm], long side length 9098 [mm], loading load 100.0 [kg /
m ² ], etc., as well as a boundary condition that a pin support exists at the position of △ shown in FIG. In addition, the description will be made on the assumption that the direction parallel to the void is the X direction and the direction orthogonal to the void is the Y direction.

The dividing unit 20 converts the model of the hollow slab into the X direction and the Y direction parallel to the floor based on the input number of divisions.
Multiple (substantially square) divided equally in each direction
It is divided into rectangular elements, and a number is assigned to each divided node and each element. As shown in FIG. 4, a node number is assigned to each node, and an element number is assigned to each element as shown in FIG. The respective means (strain calculating means, stress calculating means, first to third determining means, rebar amount calculating means) of the processing unit 2 will be described below for each element of the hollow slab model divided by the dividing unit 20. Perform processing.

The strain calculator 21 calculates a relational expression {P} = [K] {δ}, which indicates the relation between the load and the displacement, where ({P}: load vector, [K]: rigidity matrix, {δ} : Displacement vector), the displacement at the node of each element is calculated. Here, the rigidity matrix [K] is
It is obtained by the following equation using a bending stiffness matrix [D] taking into account the orthogonal anisotropy described later.

(Equation 13) (Where [C] is a coefficient matrix depending on the shape,
[Q]: Distortion transformation matrix) The components of the load vector are set based on the analysis conditions input as the input data described above. Further, a distortion which is a displacement per unit length is calculated from the calculated displacement. Next, the stress calculator 22 calculates a relational expression {σ} = {M} = [D] {ε} (1) where {σ}, {M}: stress vector, [ D]: Bending rigidity matrix, {ε}: Bending rigidity matrix [D] used for strain vector is calculated. For an isotropic plate (floor), the bending stiffness matrix [D] is
Equation (2)

[Equation 14] ... (2) Where E is the modulus of longitudinal elasticity (Young's modulus), t
Represents the plate thickness (floor thickness), and ν represents the Poisson's ratio. In the case of ordinary concrete, the modulus of longitudinal elasticity E is calculated by the following equation (3). E = 2.1 × 10 ⁵ (Fc / 200) ^1/2 [kg / cm ² ] (3), (Fc: concrete design strength)

The hollow slab to be designed by the hollow slab structure designing apparatus 1 has an orthotropic property whose principal axis of anisotropy coincides with the X and Y axes. The bending rigidity matrix [D] can be expressed by equation (4).

(Equation 15) (4) In the present embodiment, the coefficients k _x , k _x representing the ratio of D ₁ , D _x , D _y, D _xy to the element of the bending stiffness matrix equation [D] in the case of an isotropic plate _y, with k _1, k _xy, is as follows.

(Equation 16) Inner k _x of these coefficients, k _y is, I _x or I _y shown below
And the normal second moment of area I ₀ (= I
_p ). ^{_{I 0 = bt 3/12 ...}} (5) Here, b is a unit width of the hollow slabs, t represents the floor thickness. Hereinafter, the direction coincident with the axis of the void is assumed to be the X axis, and the coefficient k
_x, k _y, a k _1, k _xy How to find the show.

[0027] 1) coefficient k calculated X-plane of _x, has a cross section having a hollow diameter phi, expression of the bending moment about the X-plane normal second moment ^{_{(6) I x = bt 3}} /12 -πφ obtained by the ^4/64 ... (6). The coefficient k _x is obtained from the ratio of this value to the above-described second moment of area I ₀ , that is, the equation (7) (see FIG. 6). k _x = I _x / I ₀ (7)

[0028] 2) In the calculation Y plane of the coefficient k _y, since the defective portion of a section along the void (hollow portion) along the Y-axis, the method for calculating using conventional second moment can not be employed . In this embodiment, considering the rigidity decreases due to the hollow structure, the in-plane pure bending analysis of a flat plate with a hollow cross section with a boundary element method, calculating the coefficient k _y as follows. The strain calculator 21 gives a bending moment of the same magnitude as an external force to a flat plate having a simply supported hollow cross section and a flat plate having no hollow cross section,
The horizontal displacement (d _p , d _y shown in FIG. 7) of the end is calculated. For the boundary element, for example, the left and right surfaces are divided into 20, the horizontal plane is divided into 30, and the circumference is divided into 80, and the horizontal displacement of the end is obtained.

The beam elements undergoing bending bending moment - than the curvature relationship M = EIκ ... (8), I y, cross-sectional secondary moment and curvature of the slab with a hollow cross section κ _y, I _p, the kappa _p hollow Assuming that a slab having no cross section has a second moment of area and a curvature, M = EI _y κ _y = EI _p κ _p (9) is obtained. The equation (9), the coefficient k _y are horizontal displacement d _p of the end portion, by using the d _y, equation (10) is calculated as follows. _{k y = I y / I p} = κ p / κ y ≒ d p / d y ... (10)

[0030] 3) k ₁ = k _xy calculated coefficients k ₁ and k _xy, takes the arithmetic mean of the coefficients k _x and k _y (Equation (11)). k ₁ = k _xy = (k _x + k _y ) / 2 (11)

From the above, the bending stiffness matrix [D] is calculated. Using the calculated bending stiffness matrix [D] and the strain data calculated by the strain calculation unit 21, the stress calculation unit 22 calculates the stress from the relational expression (1) indicating the relationship between the stress and the strain. Then, the strain calculator 21 and the stress calculator 22
Is output to the output unit 4. 8 to 12 show output examples calculated by the strain calculation unit 21 and the stress calculation unit 22 and output to an output unit (not shown).

FIG. 8 is a displacement diagram showing the displacement (strain) of the hollow slab and the maximum displacement (node number (19)).
9), -1.033 [mm], the node number (7
8) shows 1.556 [mm]). FIG. 9 is a bending moment diagram in the X direction.
Direction, and the maximum bending moment (-0.4 at node number (156)).
1 [tm / m] and 0.36 in the node number (83)
[Tm / m]). FIG. 10 is a bending moment diagram in the Y direction, showing the bending moment generated in the Y direction of the hollow slab, and the maximum bending moment (−1.88 [tm / m] at the node number (156)).
The node number (88) indicates 3.88 [tm / m].

FIG. 11 is a shear force diagram in the X direction, showing the shear force generated in the hollow slab in the X direction and the maximum shear force (−0.90 at the node number (155)).
[Tm / m], 0.90 in the node number (165)
[Tm / m)]). FIG. 12 is a shearing force diagram in the Y direction, showing the shearing force generated in the hollow slab in the Y direction, the maximum shearing force (-2.73 [tm / m] at the node number (145)), and the node number. (23)
, 2.30 [tm / m]). The data calculated by the strain calculation unit 21 and the stress calculation unit 22 is temporarily stored in a memory included in the processing unit 2, and is stored in the storage unit 3 according to conditions.

Next, the operation of the deflection judging section 23 will be described. The deflection determination unit 23 first obtains the maximum value of the displacement data calculated by the distortion calculation unit 21 from the memory or the storage unit 3 included in the processing unit 2. The maximum value of the displacement data is multiplied by the safety factor and the reference value, which is separately input and set from the input unit and uses the safety factor in consideration of creep and the reference value related to the safety of deflection (specified separately). The safety with respect to the deflection is determined by comparing the values.

For example, the maximum displacement of a slab (elastic deflection)
Long-term deflection δ δ _E = 0.156 [cm] (see the displacement diagram in FIG. 8) multiplied by a safety factor (= 4.0) considering creep δ δ = 0.156 × 4.0 = 0.622 [ cm] is divided by the short side of the floor (see FIG. 4) = 424.8 [cm], and the value per unit length [cm] (1/682) is compared with a reference value (= 1/250). ing. In this example,
Since the calculated value is equal to or less than the reference value, the safety relating to the deflection is determined to be OK. The result of this determination is output to the output unit.

Next, the operation of the crack determining section 24 will be described. The crack determination unit 24 first acquires the maximum value (maximum bending moment) of the stress data calculated by the stress calculation unit 22 from the memory or the storage unit 3 of the processing unit 2. The following formula (11) shows a crack moment Mc Mc = 1.8 (Fc) ^1/2 Z (11) (where Fc represents concrete design strength and Z represents a section modulus) and a maximum stress. By comparing, the safety related to the crack is determined.

For example, the section modulus in the X direction is 25474
[Cm ³ / m], concrete design strength Fc = 210
At [kg / cm ² ], the cracking moment Mc in the X direction is 6.64 [tm / m]. The maximum bending moment shown in FIG. 9 is 0.41 [tm / m], and since this value is equal to or less than the crack moment Mc, the safety relating to the crack in the X direction is determined to be OK. When the section modulus in the Y direction is 24270 [cm ³ / m], the crack moment Mc in the Y direction is 6.33 [tm / m].
Becomes The maximum bending moment 3.8 shown in FIG.
8 [tm / m] and this value is equal to or less than the crack moment Mc in the Y direction, so that the safety related to the crack in the Y direction is determined to be OK. The result of the determination is output to the output unit.

Next, before describing the operation of the rebar amount calculating unit 25, a method of evaluating the amount of rebar will be described first.

The amount of rebar required in each element divided by the division unit 20 is determined using the maximum value of the moment of the node belonging to the element. But perforated slab (hollow slab)
In the case of (1), unlike the non-porous slab (slab without a hollow structure), the concentration of stress must be considered. Therefore, the reinforcing bar amount calculating unit 25 calculates the reinforcing bar amount in each element based on the maximum value of the moment of the node belonging to each element calculated by the finite element method multiplied by the stress concentration coefficient shown in Table 1. It is carried out. (In the table, h indicates the plate thickness (floor thickness), and r indicates the diameter of the hole (void).)

[Table 1]

This stress concentration coefficient is calculated by the boundary element method as 2
It was obtained by two-dimensional elastic analysis, and the outline of the analysis is described below. A two-dimensional square plate with a hole shown in FIG. 13 is simply supported at the centers of both ends, a simple bending unit moment (see FIG. 14) is applied from both ends, and the stress (σ _x ) generated at each point is calculated. In FIG. 13, 1 to 96 are points for obtaining stress, 1 to 31 are element lower ends, 32 to 62 are element upper ends, and 63 to 96 are points inside the element. The boundary element is
It is a primary element, divided into 30 equal parts in the width direction and 20 parts in the height direction.
Equally divided, the area around the hole is divided into 80 equal parts. Plate thickness (h = width)
And the diameter (r) are divided into two cases of 125 [mm] and 150 [mm], and the plate thickness (h = width) is set to 250 [m].
m] to 700 [mm] were calculated in steps of 25 [mm].

FIG. 15 (hr = 125) shows the calculation results. The horizontal axis indicates the number of points shown in FIG. 4, those vertical axis to the absolute value of the stress (sigma _x) when there is the hole, divided by the maximum value of the stress (sigma _x) that occur when the hole is not (For each pipe size shown at the right end). The legend in FIG. 15 indicates h, and it can be seen that stress concentration occurs as h increases (that is, as the ratio of diameter to height increases). From the calculation results, the sheet having the largest stress concentration coefficient was extracted for the sheet thickness (h) and the difference between the sheet thickness and the hole diameter (hr), and the sheet thickness (h) and the sheet Table 1 shows the stress concentration coefficients relating to the difference (hr) between the thickness and the diameter of the hole.

Next, the operation of the rebar amount calculating unit 25 will be described. Rebar amount calculating section 25, a reinforcement amount N necessary for hollow slabs, but the following equation N '= αM × 10 ² / of _{(f t ja s B) ...} (12), α: stress concentration factor for element shapes, M: maximum value of the stress _{[tm / m], f t} : allowable tensile stress of the rebar ^{[t / cm 2], j} : stress center distance (= d × 7/8) [cm], a s: using The cross-sectional area [cm ² ] per rebar, B: unit width [cm], is calculated as a value N obtained by rounding up the decimal value of N ′. Incidentally, the stress concentration factor α is computed in the manner described above, also, reinforcement of allowable tensile stress of f _t, the distance d to the rebar and underfloor surface being Haisuji, the cross-sectional area a _s per rebar one to be used, It is assumed that the unit width B is input from the input unit 3 and stored in the storage unit 3 in advance.

The rebar amount calculation unit 25 obtains the maximum value of the moment (stress) calculated by the stress calculation unit 22 from the memory or the storage unit 3 of the processing unit 2, and further obtains the required data from the storage unit 3. Then, the rebar amount is calculated from the equation (12). The rebar amount calculated here is the distance d (four types) between the reinforcing bar arranged in each direction and up and down and the floor bottom (FIG. 16).
), A unit width B (unit width [cm] in the direction orthogonal to the void (see FIG. 17), and 100 in the direction parallel to the void.
[Cm]), and is calculated for each of the vertical direction in the void parallel direction and the vertical direction in the void orthogonal direction. The result of the calculation is output to the output unit. Note that the maximum moment of a node constituting each element is defined as the maximum value of the moment (stress) of the element.

FIGS. 18 to 21 show output examples. In this example, H = 40 [cm], d _x = 34.0 [cm], d _y =
35.0 [cm], (j _x = 29.8 [cm], j _y = 3
0.6 [cm]), α _x = 1.208, α _y = 1, a _s =
1.27 [cm ² ] and f _t = 2.0 [t / cm ² ]. In these figures, the number of reinforcing bars required for each of the divided elements is shown in a cell corresponding to each element. In the present calculation example, D13 rebar (a _s = 1.27
[Cm ² ], ft = 2.0 [t / cm ² ]). The numerical value written on the white background is 1
The number of required reinforcing bars per [m] is the number per unit width in the hatched portion.

Next, the operation of the shear force judging section 26 will be described. The shearing force determination unit 26 determines the shearing force generated in each section of the hollow slab by a separately determined reference value (allowable stress) fs and a shearing stress τ calculated by the following equations (13) and (14). And its safety is determined. (1) void parallel _{τ = Q i × 1000 × (} B / 100) / (b × j i) = Q i × 10 × (B / b) / (7/8 × (H-5)) [kg ^{/ cm 2] ... (13)} (2) void orthogonal direction _{τ = Q i × 1000 × (} 100 × j i) = Q i × 10 / (7/8 × (H-φ)) [kg / cm 2] (14) Here, i = x, y, and Q _i and j _i represent a shear force and a distance between stress centers in a void parallel direction (X direction) or a void orthogonal direction (Y direction). B is the distance between void centers, b is the distance between void outer diameters, H is the floor thickness, and φ is the void diameter (see FIG. 22).

For example, in the X direction, the shear force Q _x is 0.90 [t / m], and the shear stress τ is 0.69 [kg].
/ Cm ² ] and the reference value fs is 7.00 [kg / cm ² ], τ <fs, and the determination is OK. Further, with respect to the Y direction, the shear forces Q _y is 2.73 [t / m], when the shear stress of tau is 2.38 [kg / cm ^2], a tau <fs determination becomes OK. The result of the determination is output to the output unit.

Next, the hollow slab structure designing apparatus 1
An example of the structure calculation of a reinforced concrete floor plate structure having a step will be described.

In this structural calculation example, the hollow structure shown in FIG.
In a slab having a slab structure S1, FIG.
A step having a floor plate structure S2 which is a non-porous slab shown in FIG.
This is an example when there is a part. Analysis conditions of this structural calculation example and
The floor plate structure S1 has a plate thickness of 25.0 [cm] and a hole diameter of
12.5 [cm], finishing load 50.0 [kg /
m^Two], The slab own weight is 482.2 [kg / m]^Two], Loading
Weight is 180.0 [kg / m^Two] And the floor plate structure S2
Has a thickness of 20.0 [cm] and a finishing load of 50.0 [k].
g / m^Two], Slab own weight 480.0 [kg / m^Two]
Shall be. In addition, using concrete,
240kg / cm ^Two], Young's modulus
(E) is 320.04 [t / cm]^Two], Poisson's ratio
(Ν) is reduced to 1/6, and the reinforcing bar design strength (Fs) is set to 2000.
[Kg / cm^Two]. And the short side length of the floorboard is 6
800 [mm], long side length 8400 [mm], floor
Divide the plate into 16 equal parts in the short side direction and 20 equal parts in the long side direction
(See FIG. 24). Furthermore, as a boundary condition,
The outer periphery is fixedly supported, and the fixed degree is 85% and 60%.
FIG. 25 shows that there is a% portion.

When the above analysis conditions are input to the hollow slab structure designing apparatus 1, the dividing section 20 divides the floorboard into equal parts as shown in FIG. 24, and assigns node numbers to the respective nodes.
An element number is assigned to each element as shown in FIG. Then, the strain calculation unit 21 calculates the displacement and the strain from the analysis conditions. The calculated displacement data is output to the output unit as a displacement diagram shown in FIG. This figure shows that a maximum displacement (1.830 [mm]) occurs at the node number 179 with the node number 1 as a reference (0,000 [mm]).

The stress calculator 22 sets a bending stiffness matrix (Equation (4)) based on the input analysis conditions. Under the above analysis conditions, the components of the bending stiffness matrix for the floor panel structure S1 are D1 = 499.8 [tm] and Dx =
2967.5 [tm], Dy = 3030.5 [tm],
Dxy = 1249.6 [tm], and the component of the bending stiffness matrix for the floor panel structure S2 is D1 = 262.9.
[Tm], Dx = 1577.4 [tm], Dy = 157
7.4 [tm] and Dxy = 657.3 [tm].
Then, based on the strain data calculated by the strain calculator 21, the stress generated in the floorboard is calculated. The calculated stress data is output to the output unit as a moment diagram, a shear force diagram, and a fulcrum reaction force diagram. Output examples of stress data in this structural calculation example are shown in FIGS. 27 to 31 respectively
A bending moment diagram in the X direction, a bending moment diagram in the Y direction, a shear force diagram in the X direction, a shear force diagram in the Y direction, and a fulcrum reaction force diagram are shown.

The maximum displacement (elastic deflection) δ _E calculated by the strain calculating means 21 occurs at the node number 179 as shown in FIG. 26, and δ _E = 0.183 [cm].
The deflection determining unit 23 calculates the long-term deflection δ in consideration of creep.
Is calculated. In this example, δ = 0.183 × 4.0 = 0.
732 [cm]. This value and the short side length (l
_min ) of 680.0 [cm], 1/929 which is a long-term deflection per unit length in the short side direction (δ / l _min ) is calculated, and this value is compared with a reference value 1/250. .
In this example, the long-term deflection per unit length in the short side direction is equal to or less than the reference value, and is determined to be OK.

The crack determining section 24 calculates a crack moment from equation (11). The concrete design strength (Fc) under the analysis conditions is 240 [kg / cm ² ].
The section modulus Z in the X direction of the floor plate structure S1 is 10033 [cm
³ / m], and 2.80 [tm], which is the crack moment (Mc) in the X direction, is calculated from Expression (11). On the other hand, as shown in FIG. 27, the maximum value of the bending moment in the X direction is -1.75 [tm /
m]. The crack determination unit 24 compares and determines the calculated X-direction crack moment (Mc) with the maximum value of the X-direction bending moment calculated by the stress calculation unit 22. In this example, since the maximum value of the bending moment in the X direction is equal to or less than the crack moment (Mc), it is determined to be OK. The crack determining unit 24 further determines the Y of the floor plate structure S1.
For each of the directions and the X and Y directions of the floor panel structure S2, the same determination of the safety related to cracking as described above is performed.

The rebar amount calculation unit 25 calculates the required rebar amount using the equation (12) for each element of the divided floorboard structure. In this structural calculation example, in the case of the floor plate structure S1, the plate thickness 25
[Cm], the distance (d _x ) between the reinforcing bar and the floor under the floor in the X direction is 20.0 [cm], the stress concentration coefficient (α _y ) is 1, and the distance in the Y direction is The distance (d _y ) between the reinforcing bar and the floor under the floor is 19.0 [cm], and the stress concentration factor (α _y ) is 1.0771. In the case of the floor plate structure S2, the plate thickness is 20 [cm], and the distance (d _x ) between the reinforcing bar and the lower surface of the floor in the X direction is 1
5.0 [cm], the stress concentration factor (α _x ) is 1, and Y
In the direction, the distance (d _y ) between the reinforcing bar and the floor under the floor is 14.0 [cm], and the stress concentration factor (α _y ) is 1
It is.

The required reinforcing bar amount calculated based on these values is output to the output unit. FIG. 32 is a diagram of the required number of upper end muscles in the X direction. In this example, D13 rebar (a _s = 1.27
[Cm ² ], ft = 2.0 [t / cm ² ]). The white portion indicates the required number per 1 [m], and the hatched portion indicates the required number per unit width. FIG. 33 is a diagram showing the required number of lower end muscles in the X direction. FIG. 33 also shows the number of rebars required under the same conditions as in FIG. 34 and 35 are Y-direction upper muscle necessary number view and Y-direction lower muscle necessary number views, respectively, D13 rebar ^{_{(a s = 1.27 [cm 2}} ], ft = 2.
0 [t / cm ² ]). The numerical value in the square is the required number of reinforcing bars per 1 [m].

The shearing force judging section 26 first calculates the equation (1)
3) Calculate the shear stress τ by using the equation (14). In this example, with respect to the X direction of the floorboard structure S1, shear force Q _x calculated by the stress calculating unit 22 is 0.90 [t /
m], 0.69 [kg / cm ² ] is calculated from equation (13) as the shear stress τ. When the reference value (allowable stress) fs is 7.40 [kg / cm ² ], τ <
fs, and the determination regarding the shearing force is determined to be OK. Similarly, the shear stress τ is calculated for the Y direction of the floor panel structure S1 and the X and Y directions of the floor panel structure S2, and each shear stress τ is compared with a reference value (allowable stress) fs. I do. The result of the determination is output to the output unit. The details of the operation of the hollow slab structure designing apparatus 1 have been described above.

A program for causing a computer to realize the structural calculation function in the hollow slab structure designing apparatus of the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is stored in a computer system. The hollow slab structure designing apparatus may be realized by reading and executing. That is, the program includes a function of dividing the hollow slab into a plurality of elements, a function of a strain calculating unit, a function of a stress calculating unit, a function of a first determining unit, a function of a second determining unit, The computer realizes the function of the rebar amount calculating means and the function of the third determining means.

The “computer system” here includes an OS and hardware such as peripheral devices. The “computer system” also includes a homepage providing environment (or a display environment) if a WWW system is used. Also,
"Computer readable recording medium" means a floppy disk, a magneto-optical disk, a ROM, a CD-ROM.
And a storage device such as a hard disk built in a computer system. Further, "computer-readable recording medium" refers to a communication line for transmitting a program through a network such as the Internet or a communication line such as a telephone line for a short time, such as a communication line.
It also includes those that dynamically store programs (transmission media or transmission waves) and those that store programs for a certain period of time, such as volatile memories in computer systems serving as servers and clients in that case. Further, the program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and the design and the like within a range not departing from the gist of the present invention. Is also included.

[0059]

As described above in detail, according to the present invention, since the structural calculation taking into account the orthogonal anisotropy peculiar to the hollow slab and the stress concentration applied to the hollow part is performed automatically, the hollow slab is automatically calculated. It is possible to easily and consistently design a structure suitable for a vehicle, and to automatically determine safety. Further, according to the present invention, it is possible to automatically calculate the amount of rebar required for each part (element) of the hollow slab.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a hollow slab structure designing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a structure of a hollow slab and a force acting thereon.

FIG. 3 is a diagram showing dimensions of a hollow slab as an example of analysis conditions.

FIG. 4 is an example of a model diagram of a hollow slab.

FIG. 5 is an example of a model diagram of a hollow slab.

FIG. 6 is a diagram showing a floor pressure and a unit width of a hollow slab and a non-porous slab.

7 is a diagram showing a horizontal displacement d _p, d _y end by stress applied to the hollow slabs and disabling the slab.

FIG. 8 is an example of a displacement diagram output by a distortion calculator.

FIG. 9 is an example of a bending moment diagram in the X direction output by the stress calculation unit.

FIG. 10 is an example of a bending moment diagram in the Y direction output by a stress calculation unit.

FIG. 11 is an example of an X-direction shear force diagram output by the stress calculation unit.

FIG. 12 is an example of a shear force diagram in the Y direction output by a stress calculation unit.

FIG. 13 is a diagram showing a simple bending state of the hollow slab.

FIG. 14 is a diagram showing inner points for evaluating values of stress applied to the hollow slab.

FIG. 15 is a view showing a stress concentration coefficient in the X direction applied to the hollow slab (when hr = 125 [mm]).

FIG. 16 is a diagram illustrating a distance d between a reinforcing bar to be arranged and a floor lower surface.

FIG. 17 is a diagram illustrating a unit width B of a hollow slab.

FIG. 18 is an example of a diagram illustrating a required number of upper-end muscles in the X direction, which is output by a rebar amount calculation unit.

FIG. 19 is an example of a diagram illustrating a required number of lower end muscles in the X direction, which is output by a rebar amount calculation unit.

FIG. 20 is an example of a diagram showing a required number of upper-end muscles in the Y-direction output by a reinforcing-bar-amount calculating unit.

FIG. 21 is an example of a diagram showing a required number of lower end muscles in the Y direction outputted by a rebar amount calculation unit.

FIG. 22 is a diagram illustrating a distance B between void centers, a distance b between void outer diameters, a floor thickness H, and a void diameter φ.

FIG. 23 is a structural example of an example of a floor panel structure having a step.

FIG. 24 is a diagram showing dimensions and node numbers of an example of a floor panel structure having a step.

FIG. 25 is a diagram showing element numbers and boundary conditions (fixed support) of an example of a floor panel structure having a step.

FIG. 26 is a displacement diagram of an analysis result of one example of a floor panel structure having a step.

FIG. 27 is a diagram showing a bending moment diagram in the X direction of an analysis result of an example of a floor panel structure having a step.

FIG. 28 is a bending moment diagram in the Y direction as a result of analysis of an example of a floor panel structure having a step.

FIG. 29 is a shear force diagram in the X direction of an analysis result for one example of a floor panel structure having a step.

FIG. 30 is a shear force diagram in the Y direction of an analysis result for an example of a floor panel structure having a step.

FIG. 31 is a fulcrum reaction force diagram of an analysis result for an example of a floor plate structure having a step.

FIG. 32 is a diagram showing the required number of upper-end muscles in the X direction as a result of analysis of an example of a floor panel structure having a step.

FIG. 33 is a diagram illustrating the required number of lower end muscles in the X direction as a result of analysis of an example of a floor panel structure having a step.

FIG. 34 is a diagram illustrating the number of upper end muscles in the Y direction as an analysis result for an example of a floor panel structure having a step.

FIG. 35 is a diagram showing the required number of lower end muscles in the Y direction as an analysis result for an example of a floor panel structure having a step.

FIG. 36 is a flowchart illustrating a process of the hollow slab structure designing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hollow slab structure design apparatus 2 ... Processing part 3 ... Storage part 20 ... Dividing part 21 ... Strain calculating part (strain calculating means) 22 ... Stress calculating part (stress calculating means) 23 ... Deflection determining part (first determining means) 24: crack determining section (second determining section) 25: reinforcing bar calculating section (rebar calculating section) 26: shear force determining section (third determining section)

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Ogiwara F-term in Fujimori Industry Co., Ltd. 1-2-17 Higashi-Shimbashi, Minato-ku, Tokyo 5B046 AA03 BA00 DA02 FA06 JA08

Claims (9)

[Claims] An input unit for inputting input data used for calculating strain and stress generated in the hollow slab; and a strain calculating unit for calculating displacement and strain of the hollow slab based on a load applied to the hollow slab. A processing unit including a stress calculation unit configured to calculate a stress generated in the hollow slab based on the strain of the hollow slab calculated by the strain calculation unit; A storage unit for storing data; and an output unit for outputting a result calculated by the processing unit, wherein the distortion calculating means is: {P} = [K] {δ}, where {P}: Load vector, [K]: rigidity matrix obtained using bending stiffness matrix [D] considering orthogonal anisotropy, {δ}: displacement vector) A load vector and a stiffness matrix are set based on the input data to calculate a displacement, and further, a strain is calculated based on the calculated displacement, wherein the stress calculating means: {M} = [D] {ε} (Where, {M}: stress vector, [D]: bending stiffness matrix considering orthogonal anisotropy, {ε}: strain vector)
Using the relational expression of stress vector and strain vector expressed by
Based on the input data and the distortion calculated by the distortion calculation means, (Equation 2) However, stress is calculated by setting k _x , k _y , k ₁ , and k _xy : coefficients considering orthogonal anisotropy, E: longitudinal elastic modulus, t: floor thickness, ν: Poisson's ratio. Hollow slab structure design equipment. 2. The method according to claim 1, wherein the strain calculating unit and the stress calculating unit include:
2. The hollow slab structure designing apparatus according to claim 1, wherein the calculation of the displacement / strain and the calculation of the stress are performed in accordance with a boundary condition for each element of the hollow slab divided into a plurality of elements. 3. 3. The stress calculation means uses a boundary element method to calculate a horizontal displacement d _p of a cross-sectional end of a solid slab and a horizontal displacement d of a cross-sectional end of a hollow slab due to a bending moment. calculates _y, wherein the value of the coefficient _{k y, k y = d p} / d y hollow slab structure design system according to claim 2, characterized in that calculated as. 4. The processing unit compares the maximum displacement of the hollow slab calculated by the strain calculating means with a safety factor in consideration of creep and a reference value, and compares the value with a reference value. The hollow slab structure designing apparatus according to any one of claims 1 to 3, further comprising a first determination unit that determines the following. 5. The processing unit comprises: a maximum stress generated in the hollow slab calculated by the stress calculating means; and Mc = k · (Fc) ^1/2 Z, where k: coefficient, Fc: concrete design strength, Z:
The method according to any one of claims 1 to 4, further comprising a second determination unit that compares a crack moment Mc expressed by a section modulus, and determines safety related to cracking of the hollow slab. Hollow slab structure design equipment. 6. The storage unit stores a stress concentration coefficient α relating to an element shape of a reinforcing bar in a direction perpendicular to the void, and the processing unit uses the stress concentration coefficient α to calculate a reinforcing bar amount N required for the hollow slab. The hollow slab structure designing apparatus according to any one of claims 1 to 5, further comprising a reinforcing bar amount calculating means for calculating by calculation. 7. The processing unit calculates τ = Qx × (B / b) / (7/8 × (H−d _t )) in the void parallel direction and τ = Qy / (7 / 8 × (H−φ)), where Qx: maximum shear force in the void parallel direction, Qy: maximum shear force in the void orthogonal direction, B: distance between void centers, b: distance between void outer diameters, H: floor thickness , Φ: void diameter, _dt : distance from the tensile edge of the floor to the center of gravity of the rebar, and the shear stress τ shown by the following and the allowable shear stress are compared to determine the safety of the shear force generated in the hollow slab. 2. The apparatus according to claim 1, further comprising a third determining unit for determining.
An apparatus for designing a hollow slab structure according to claim 6. 8. A procedure for calculating a second moment of area I _x in a void parallel direction in a slab having a hollow section, and a procedure for calculating a second moment of area I ₀ in a void parallel direction in a slab having no hollow section. A procedure of dividing the second moment of area I _x by I ₀ to calculate a coefficient k _x , and using a boundary element method, a horizontal displacement of an end of a cross section of the slab having no hollow section due to a bending moment. a step of calculating the displacement d _y horizontal sectional end of d _p and the hollow slab, by the bending moment, the horizontal displacement d _p of the cross-sectional end portion of the slab without a hollow section of the hollow slab section take a step of calculating a coefficient k _y divided by horizontal displacement d _y end, the coefficient k _x, the average of k _y, the coefficient k ₁ the average value,
Procedure for setting as _kxy , {P} = [K] {δ}, where {P}: load vector, [K]: bending rigidity matrix [D] considering orthogonal anisotropy Using the relational expression between the load vector and the displacement vector, which can be expressed by the stiffness matrix to be obtained, {δ}: displacement vector), the load vector and the stiffness matrix are set based on the input data, and the displacement is calculated. A procedure for calculating strain based on the displaced displacement, {M} = [D] {ε}, where {M}: stress vector, [D]: bending stiffness matrix considering orthogonal anisotropy, {Ε}: strain vector)
Using the relational expression of stress vector and strain vector expressed by
Based on the input data and the distortion calculated by the distortion calculation means, (Equation 4) Where k _x , k _y , k ₁ , and k _xy are coefficients considering orthogonal anisotropy, E is a longitudinal elastic modulus, t is a floor thickness, and ν is a Poisson's ratio. A method of designing a hollow slab structure, comprising: 9. A recording medium storing a strain stress calculation program in a hollow slab structure designing apparatus, wherein a cross section in a void parallel direction of a slab having a hollow cross section is provided.
Calculating the second moment I _x , calculating the second moment I ₀ in the void parallel direction in the slab having no hollow section, dividing the second moment I _x by I ₀ , and calculating the coefficient k _x Using the boundary element method, the horizontal displacement d _p of the cross-sectional end of the slab having no hollow section and the horizontal displacement d _y of the cross-sectional end of the hollow slab are calculated by using the boundary element method. Calculating a coefficient k _y by dividing the horizontal displacement d _p of the cross-sectional end of the slab having no hollow section by the horizontal displacement d _y of the cross-sectional end of the hollow slab due to the bending moment. a step of said coefficient k _x, take the average of k _y, the coefficient k ₁ the average value,
Procedure for setting as _kxy , {P} = [K] {δ}, where {P}: load vector, [K]: bending rigidity matrix [D] considering orthogonal anisotropy Using the relational expression between the load vector and the displacement vector, which can be expressed by the stiffness matrix to be obtained, {δ}: displacement vector), the load vector and the stiffness matrix are set based on the input data, and the displacement is calculated. A procedure for calculating strain based on the displaced displacement, {M} = [D] {ε}, where {M}: stress vector, [D]: bending stiffness matrix considering orthogonal anisotropy, {Ε}: strain vector)
Using the relational expression of stress vector and strain vector expressed by
Based on the input data and the distortion calculated by the distortion calculation means, (Equation 6) However, k _x , k _y , k ₁ , k _xy : a coefficient considering orthogonal anisotropy, E: longitudinal elastic modulus, t: floor thickness, ν: Poisson's ratio, and a procedure for calculating stress by computer A computer-readable recording medium storing a strain stress calculation program to be executed by a computer.