TWI558893B - Corrugated steel plate design method, and corrugated steel plate groove - Google Patents

Description

Corrugated steel plate design method and corrugated steel plate groove

The present invention relates to a method for designing a corrugated steel sheet for designing a corrugated steel sheet having a U-shaped corrugated steel sheet groove formed of a corrugated steel sheet (in particular, a wave shape thereof), and using a corrugated steel sheet obtained according to the design method The corrugated steel plate is formed into a groove.

In the corrugated steel sheet groove, a corrugated steel sheet 1a having a corrugated shape as shown in FIG. 4 is used, and as shown in FIG. 3, the wall portion 2 on both sides and the bottom portion 3 of the length d of the bottom straight portion are U-shaped cross-sectional shapes, which are called Corrugated grooves, U-shaped grooves, etc. are used when constructing various open waterways or drainage channels (open channels). Such a corrugated steel sheet groove is generally constituted by a corrugated slice (corrugated steel plate) which is defined as "corrugated pipe and corrugated slice" in Japanese Industrial Standard JISG 3471.

As the type of the corrugated steel sheet used in the groove of the corrugated steel sheet, there are a type 1 and a type 2 slice having the same cross-sectional shape as the type 1 and type 2 (corrugated section) of the corrugated tube specified in JIS, and the type 1 section. The distance b between the cross-sectional shape waves is 68 mm, the depth H of the wave is 13.0 mm, and the distance between the cross-shaped shape waves of the circular type 2 slice is 150 mm, and the depth H of the wave is 48 mm or 50 mm.

The corrugated steel sheet groove of the type 1 slice is constructed, for example, in a cross-sectional shape as shown in Figs. 10(a) and (b). The reinforcing side angle 4 is bolted along the upper end portion of the side wall 2, and the two side walls 2 are formed by a struts (supporting protective members) 5 formed by joining the mountain-shaped steel between the upper ends thereof in the groove length direction (Fig. 10 with The direction perpendicular to the paper surface is reinforced by the spacing design.

The type of Figure 10(a) contains 1 slice, but the type of Figure 10(b) contains left and right. 2 pieces, the bottom 3 has a bolt joint.

The cross-sectional shape of the corrugated steel plate using the type 2 slice is substantially the same as the above type (a), but the span is large, so as shown in Fig. 11, including the symmetrical left and right slices and the bottom slice, the three slices, the bottom 3 There are bolt joints at two places.

The corrugated steel sheet used in Patent Document 1 is different from the use of the open channel, and is used as a load supporting structure. However, the corrugated steel plate has a cross-sectional shape wave spacing of 30.5 cm (12 inches) and a wave depth of 10.2 cm. (4 miles).

As described above, in the conventional corrugated steel sheet (corrugated section) used in the groove of the corrugated steel sheet, the depth of the wave is set to a specific size, but the specific size thereof is related to the amount of steel used for the strength of the corrugated steel sheet groove. The efficiency is unfounded.

Further, in the corrugated steel sheet described in Patent Document 1, the depth of the wave is as large as 102 mm (10.2 cm), and the efficiency of the amount of the steel used for the structure constructed using the corrugated steel sheet is still unreliable.

Prior technical literature Patent literature

Patent Document 1: Japanese Special Open 53-620

When constructing a U-shaped waterway or a drainage road, etc., if it is to be constructed, the span (the distance between the U-shaped walls) and the large span are allowed when the corrugated steel plate is grooved using the previously standardized corrugated steel plate. In order to increase the rigidity, it is necessary to change at least the profile of the corrugated steel sheet. shape.

When the cross-sectional shape of the corrugated steel sheet is changed, the amount of steel used exceeds the necessary amount due to the strength of the groove of the corrugated steel sheet, and the construction cost becomes high due to an increase in the material cost. Therefore, it is necessary to avoid the need for the strength of the corrugated steel sheet groove. It is an effective cross-sectional shape in relation to the amount of steel used.

However, the current situation is a method for calculating the effective cross-sectional shape of the corrugated steel sheet used for the corrugated steel sheet groove in which the U-shaped side walls are subjected to external pressure.

In the corrugated steel plate used in the corrugated steel plate groove which is subjected to external pressure on the U-shaped side walls, the discussion is made. In the method of calculating the effective cross-sectional shape, the inventors of the present invention paid attention to the fact that the effective cross-sectional shape is not sufficiently considered from the viewpoint of the secondary moment of the cross section. That is, in the structure in which the U-shaped side walls are subjected to external pressure, there is a case where the bottom straight portion material is degraded with respect to the applied load and is damaged, and the bottom straight portion is broken due to buckling, and therefore, attention is paid to the relative fall. The cross-sectional shape in which the damage caused by the damage due to the buckling is balanced is an effective cross-sectional shape, and the present invention has been obtained.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a corrugated steel plate groove which can be formed by a cross-sectional shape of a corrugated steel sheet of the present state, and which can be obtained from a groove of corrugated steel sheet and steel. The design method of the corrugated steel sheet (especially the wave shape) of the effective cross-sectional shape of the corrugated steel sheet and the corrugated steel sheet groove constructed by the corrugated steel sheet obtained by the design method are used.

The method for designing a corrugated steel sheet according to the invention of the first aspect of the present invention is characterized in that a corrugated steel sheet having a corrugated steel sheet having a waveform of a depth H of a wave and having a U-shaped bottom straight portion length d of both side walls and a bottom portion is designed. In the wave shape of the corrugated steel sheet of the groove, the entire buckling corresponding pressure p _cr when the bottom of the groove of the corrugated steel sheet is bent by the external pressure acting on the outer surfaces of the two side walls is equal to the relief stress σ _y at the time of the fall In this manner, the depth H of the wave with respect to the length d of the bottom straight portion is set.

According to a second aspect of the invention, in the method for designing a corrugated steel sheet according to the first aspect, the length of the straight portion relative to the bottom portion is set such that the total buckling pressure p _cr and the relief stress σ _y shown in the following formula (1) are equal. Depth of wave d; where d: bottom straight line length mm p _cr : total buckling corresponding pressure N/mm ² E: elastic coefficient N/mm ² σ _y : fluctuating stress N/mm ² B: width of corrugated steel plate ( = length in the direction orthogonal to the wave of the corrugated steel plate groove) mm I: the secondary moment of the profile of each width B of the corrugated steel plate mm ⁴ A: the sectional area per width B of the corrugated steel plate mm ²

According to a third aspect of the invention, in the method for designing a corrugated steel sheet according to the second aspect, the depth H of the wave with respect to the length d of the bottom straight portion is set according to the following formula (7), wherein a: the amplitude of the wave (=H/2) )mm t: plate thickness mm

The technical solution 4 is characterized in that in the design method of the corrugated steel sheet of the second aspect, the depth H of the wave with respect to the length d of the bottom straight portion is set according to the following formula (9), wherein a: the amplitude of the wave (=H/2 )mm

The design method of the corrugated steel sheet according to claim 5 is characterized in that the corrugated steel sheet groove of the corrugated steel sheet groove constituting the corrugated steel sheet having the waveform of the depth H of the wave and having the U-shaped bottom straight portion length d of both side walls and the bottom portion is designed. In the wave shape, the entire buckling pressure p _cr when the bottom of the corrugated steel plate groove is buckling by the external pressure acting on the outer surfaces of the two side walls is equal to the relief stress σ _y when the outer pressure is lowered. The relationship between the length d of the bottom straight portion and the depth H of the wave is such that the depth H of the wave with respect to the length d of the bottom straight portion is set such that the buckling load is greater than the falling load.

The sixth aspect of the present invention is characterized in that, in the method for designing the corrugated steel sheet of the fifth aspect, the method includes the steps of: setting a bottom of the groove of the corrugated steel sheet by buckling by a horizontal action on the outer surfaces of the outer surfaces of the two side walls; a first relationship line in which _{cr is} equal to the depth H of the wave of the length d of the bottom straight portion d when the fluctuation stress σ _y when the external pressure is lowered; and the first relationship line is set for each specific interval. The depth H of the wave of the length d of the bottom straight portion is a second relationship line that changes stepwise; and the depth H of the wave with respect to the length d of the bottom straight portion is set based on the second relationship line; and the first One of the relationship lines is a region where the buckling load is greater than the load of the load, and the other region of the first relationship line is a region where the undulation load is greater than the buckling load; the second relationship line is set in the above region, in a specific In the interval, the depth H of the wave is fixed regardless of the change in the length d of the bottom straight portion.

The method for designing a corrugated steel sheet according to the invention of claim 7 is characterized in that the corrugated steel sheet groove of the corrugated steel sheet having a wave shape having a wave depth H and having a U-shaped bottom straight portion length d of both side walls and a bottom portion is designed In the wave shape of the steel plate, the depth H of the wave with respect to the length d of the bottom straight portion is set according to the following formula (8), where a: wave amplitude (=H/2) mm t: plate thickness mm [number 4]

The corrugated steel sheet groove according to the invention of claim 8 is characterized in that: the wave of the corrugated steel sheet in the corrugated steel sheet groove including the corrugated steel sheet having the wave depth H and the bottom portion of the bottom portion having a U-shaped bottom portion and the bottom portion The depth H has a size determined according to the design method of the corrugated steel sheet according to any one of the first to seventh aspects.

In the corrugated steel sheet obtained by the design method of the present invention, the depth H of the wave corresponding to the length d of the specific bottom straight portion of the groove of the corrugated steel sheet is the total buckling when the bottom portion of the groove of the corrugated steel sheet formed of the corrugated steel sheet is bent. The corresponding pressure p _cr is set in such a manner as to be equal to the relief stress at the time when the straight portion of the bottom portion is lowered. In other words, in the groove of the corrugated steel sheet formed of the corrugated steel sheet, the entire buckling corresponding pressure p _cr at the time of the bottom straight portion of the groove of the corrugated steel sheet is substantially equal to the relief stress σ _y when the bottom straight portion is lowered.

Therefore, the whole buckling and the fall are generated at the same time. There is a margin for the overall buckling when there is a margin for the overall buckling, or a buckling for the opposite, which means that the profile of the corrugated steel plate groove is not fully burdened by the applied load; and the overall buckling and the undulation generally occur at the same time. The component profile is fully burdened by the applied load. Therefore, such a cross-sectional shape can be said to be an effective cross-sectional shape (wave shape) in relation to the strength of the corrugated steel sheet groove and the amount of steel used.

In the formula (1) of the second aspect, when the cross-sectional shape is designed according to the invention of claim 1, the depth of the wave is set such that the total buckling pressure p _cr is equal to the equivalent depressing pressure p _y (= 2 × wave) The specific form of the amplitude a).

In the third aspect, a direct expression for setting the depth H (= 2a) of the wave of the corrugated steel sheet according to the invention of claim 2 is shown. In this equation, if the value of the plate thickness t is obtained, the relationship between the bottom straight line length d and the wave depth H (= 2a) can be directly obtained.

In the fourth aspect of the invention, the direct type of the depth H (= 2a) of the corrugated steel sheet is set according to the invention of the second aspect. However, in the fourth aspect, the influence of the thickness t of the technical solution 3 is small. Therefore, the term of the plate thickness t is omitted, and a simplified expression as a direct relationship between the bottom straight line length d and the wave depth H (= 2a) is shown. Thereby, the wave design of the corrugated steel sheet becomes extremely simple.

Hereinafter, a method of designing a corrugated steel sheet according to the present invention and a groove made of a corrugated steel sheet formed of a corrugated steel sheet obtained by the design method will be described with reference to the drawings.

[Example 1]

In the embodiment of the present invention, when the corrugated steel sheet including the corrugated steel sheet having the waveform of the depth H of the wave and the corrugated steel sheet groove having the U-shaped bottom straight portion length d of both sides and the bottom portion is designed, when all the bottom grooves of the corrugated sheet manufactured by the above-described level applied to the outer surface of the side walls to flex beyond the respective pressure p _cr buckling and yield when the external pressure by the above-described yield stress σ _y is equal to the embodiment, with respect to the set The depth H of the wave of the length d of the bottom straight portion.

This is illustrated in Figure 1, such as (a) corrugated steel plate groove 1 on the sides of its sides When the outer surface of the wall 2 is subjected to horizontal external pressure (indicated by an arrow), the compressive load acts on the straight portion of the bottom portion 3 (the portion of the bottom straight portion length d). Fig. 2 shows the state in which the compression load (indicated by the hollow arrow) acts on the straight portion of the bottom portion. At this time, as a failure state, as shown in FIG. 1(b), the bottom straight portion does not maintain a straight state and the buckling of the buckling is broken, and the bottom straight portion is compressed as shown in FIG. 1(c). The situation of the fall and fall of the fall. In Figs. 1 (b) and (c), the two-dot chain line indicates the original cross-sectional shape of the corrugated steel sheet groove, and d' and d" indicate the length of the portion corresponding to the original bottom straight portion length d.

Fig. 4 shows the wave shape of a general corrugated steel sheet used in the corrugated steel sheet groove, b represents the inter-corrugation distance, H represents the depth of the corrugation, and t represents the sheet thickness. As shown in the figure, the wave shape of a general corrugated steel sheet is formed by a combination of a straight line and a curved line, but from the viewpoint of calculation simplification, as shown in Fig. 5, the wave shape is approximated as a sin wave (sinusoidal curve).

In Fig. 5, the distance between the b-series waves and the amplitude of the a-series wave (=H/2 (one-half of the depth H of the wave). Further, as shown, the plate thickness t is a distance between approximately two Sin waves.

The above-described overall buckling corresponding pressure p _cr is expressed by the formula (1). The formula (1) of the total buckling corresponding pressure p _cr is derived according to the two-pin pin support boundary conditions of the Euler's Formula.

The symbols p _cr , E, σ _y , I, A, B, and d of the above formula (1) are as follows.

d: bottom straight line length mm p _cr : total buckling corresponding pressure N/mm ² E: elastic coefficient N/mm ² σ _y : fall stress N/mm ² B: width of corrugated steel plate (= width of corrugated steel plate groove (tube Length in the axial direction)) mm I: the secondary moment of each width B of the corrugated steel sheet mm ⁴ A: the sectional area of each width B of the corrugated steel sheet mm ²

In the present invention as described above, the wave shape of the corrugated steel sheet is set such that the total buckling pressure p _cr at the time of the bottom straight portion of the groove of the corrugated steel sheet is equal to the relief pressure σ _y at the time of the fall. That is, σ _y = p _cr , so the following formula (2) is directly established.

A in the formula (2) (the cross-sectional area of the width B of the corrugated steel sheet) can be obtained by calculating the cross-sectional area of one wavelength (the distance b between the waves) so as to be B/b times, as described in the formula (3). ) is shown in the following paragraphs. The "B/b" in the formula (3) is the above B/b times.

The method of formula (3) which derives the sectional area A of the width B of the corrugated steel sheet is shown in Fig. 6. The area surrounded by the URSV of Fig. 6 is the area of the 1/4 portion of the distance b between the waves, and thus is 1/4 (A/4) of the sectional area A. The sectional area A/4 (= area URSV) is the area surrounded by URZ - the surface surrounded by VSZ product. Therefore, the formula (3) is obtained. Solving the right side of equation (3) yields equation (4).

[Number 8] A=B. t.........(4)

In addition, the calculation process on the right side of the equation (3) is as follows.

I (the secondary moment of the profile) of the equation (2) is the same as the case of A, and can be obtained by calculating the secondary moment of the profile of one wavelength (the distance b between the waves) so as to be B/b times, as in the equation ( 5) shown.

The method of extracting the equation (5) of I (cross-sectional secondary moment) of the corrugated steel sheet is shown in Fig. 7. The secondary moment i of the section surrounded by the URSV of Fig. 7 is 1/4 of the secondary moment of the profile of 1 wavelength (wave distance b). And, the secondary moment i of the section (= the secondary moment of the section of the URSV portion) is the section secondary moment i ₂ of the section surrounded by the secondary moment i _{1 -} VSZ of the portion surrounded by the URZ (i = i ₁ - i ₂ ). Therefore I=4. B/bi, obtain the formula (5).

Further, for example, the sectional secondary moment i ₁ of the portion surrounded by the URZ is a sectional secondary moment y ₂ around the neutral axis (X axis) of the minute area ΔK portion in Fig. 7 . ΔK is integrated from y=0 to y=a+t/2. The same is true for the secondary moment i _{2 of the} profile.

Solving the right side of equation (5) yields equation (6).

As the A and I in the formula (2), the A of the formula (4) and the I of the formula (6) are substituted, and the amplitude a of the wave is sorted to obtain the formula (7).

The equation (7) indicates a condition in which the total buckling pressure p _{cr is} equal to the relief stress σ _y (the relationship between the plate thickness t and the amplitude a of the wave of the bottom straight portion length d).

According to the formula (7), the distance b between the waves is independent of the condition that the total buckling pressure p _cr and the undulation stress σ _y are equal. However, the magnitude of the total buckling pressure p _cr itself is of course related to the formula (1) (the reason is that if the distance between the waves changes, the sectional area A and the secondary moment I of the section change).

When the SS330 of the same material as that of the circular corrugated pipe is used, the relationship of the formula (7) is shown in Fig. 8 for the two types of the plate thickness t of 2.7 mm and 4.0 mm. In the figure, the vertical axis is corrected to the depth H of the wave (twice the amplitude a of the wave).

In addition, in the formula (7), E = 2.1 × 10 ⁵ N / mm ²

σ _y = 205 N/mm ² .

As shown in Fig. 8, the relationship between the length d of the bottom straight portion and the depth H of the wave is almost a straight line. Further, in the case where the sheet thickness t is 2.7 mm, the relationship between the length d of the bottom straight portion and the depth H of the wave, and the relationship between the length d of the bottom straight portion and the depth H of the wave when the thickness t is 4.0 mm is shown in Fig. 8. It can be seen as one relationship line, almost the same (actually 2 lines, which can be recognized in the color display).

When the relationship between the length d of the bottom straight portion and the depth H of the wave is on the relationship line of Fig. 8, the buckling load is equal to the fluctuating load (the total buckling pressure is equal to the fluctuating stress), and the cross-sectional shape is in the corrugated steel plate groove (corrugated The endurance of the tank is most effective in relation to the amount of steel used.

The area above the relationship line is the area where the buckling load is greater than the load. That is, the damage of the corrugated steel sheet groove in this region is caused by the fall. Moreover, the area below the relationship line is the region where the relief load is greater than the buckling load. That is, the failure of the corrugated steel sheet groove in this region is caused by buckling. The relationship between the length d of the bottom straight portion and the depth H of the wave is shifted upward or downward from the relationship line, then The greater the difference between the buckling load and the undulating load, the lower the cross-sectional shape, and the increased amount of steel used for the required allowable load.

As described above, the relationship between the length d of the bottom straight portion and the depth H of the wave is optimal on the relationship line of Fig. 6 from the viewpoint of the required allowable load and the efficiency of the amount of steel used.

However, if the buckling load is greater than the load, the buckling failure does not precede the failure, and the toughness of the structure using the corrugated pipe is increased to prevent the occurrence of sharp damage. Therefore, it is desirable to use the buckling load in the region above the relationship line to be more significant. The range of areas of load.

In other words, the relationship between the length d of the bottom straight portion and the depth H (H = 2a) of the wave is set as shown in the formula (8), and it is preferable to prevent the occurrence of sharp breakage.

By setting the depth H (= 2a) of the wave of the length d of the bottom straight portion as described above, the following effects are obtained.

. The material strength can be effectively utilized, and the steel can be effectively used, thereby saving the amount of steel used.

. It can be applied to corrugated steel plate groove structure with large span.

. The number of support members such as pillars can be reduced, and the amount of steel used can be reduced or the workability can be improved. Further, when the number of the support protective members is the same and the size is small, the amount of steel used can be reduced.

. The section rigidity (secondary moment of the section) becomes high, so that the sheet thickness can be made thin under the same load conditions.

. The depth H of the wave is deepened so that the amount of adhesion to the ground plate is increased, so that it can be set on a steeper slope than before.

. Deepen the depth H of the wave so that the flow rate does not become faster than necessary, and there is no need for an energy dissipating device on the steep slope

. When the buckling load is set to be greater than the load of the load, the buckling failure does not precede the failure, and the toughness of the corrugated steel plate groove is increased to prevent the occurrence of sharp damage.

As described above, the relationship line in FIG. 8 is almost a straight line, and is almost visible as one regardless of the plate thickness t. In the formula (7), the term of the plate thickness t is significantly smaller for the length d of the bottom straight portion. The influence of the thickness t can be ignored. That is, even if the length d of the bottom straight portion in the formula (7) is set to be the smallest 2000 mm in Fig. 8, the plate thickness t is set to be 4.0 mm thick, which also satisfies d ² = 4 × 10 ⁶ , t ² = 16,d ² 》t ² , therefore, it is considered that even if the values of the respective coefficients (2σ _y / π ² E, 1/6) are taken into consideration, the influence of the thickness t can be ignored (detailed calculation is omitted).

Therefore, instead of the formula (7), an approximation formula of the formula (9) which is practical can be used.

As in equation (7) or (9), the relationship between the length d of the bottom straight portion and the depth H (= 2a) of the optimum wave depends on the relief stress (σ _y ) (no elastic coefficient E due to the type of steel) difference). Therefore, the relationship between the length d of the bottom straight portion and the depth H (= 2a) of the optimum wave can be obtained from the stress of the steel used. For example, SS330, which is widely used as a material for corrugated grooves, has a lodging stress of 205 N/mm ² . Further, as a specific range, the sheet thickness t is 1.6 to 9.0 mm. The modulus of elasticity is 20.1 × 10 ⁴ ~ 21.6 × 10 ⁴ N / mm ² . The stress σ _y is 168~325 N/mm ² .

Such a design method is particularly effective when the length d of the straight portion at the bottom of the corrugated steel sheet groove is large. When the length of the bottom straight portion is small, the strength measures can be sufficiently performed to adjust the thickness of the plate without excessively providing the reinforcing member. On the other hand, when the length of the bottom straight portion is large, the necessity of using a large number of reinforcing members is generated. With such an optimum design method of the present embodiment, such a reinforcing member can be reduced. In the above-described embodiment, an example in which the length d of the bottom straight portion is in the range of 2000 mm or more is shown as a range in which the effect is remarkable. The lower limit of the length d of the bottom straight portion is not limited to 2000 mm, and may vary depending on materials, etc., and may be, for example, 1000 mm or 3000 mm. The upper limit is not particularly limited, but may be 6000 mm. Further, in the embodiment, the example in which the length d of the bottom straight portion is in the range of 5000 mm or less is shown.

Further, based on the graph of Fig. 8, as long as the relationship between the buckling load and the falling load is equal, or the buckling load is greater than the area under which the load is applied, how to set the depth H of the wave with respect to the length d of the bottom straight portion, but The upper limit is specified for this area. For example, the upper limit can also be specified in consideration of the safety rate. Specifically, as shown in FIG. 12, a relationship line between the length d of the bottom straight portion and the depth H of the wave such as "buckling load/safety rate=falling load" is set. Here, the security rate = 1.68. The depth H of the wave relative to the diameter D can also be set as the "buckling load" The relationship between the relationship between the weight = the load and the "buckling load / safety rate = the load of the load". Thereby, the buckling failure can be prevented from first hitting the failure, and sufficient safety can be ensured for the strength of the fall. In addition, as long as the safety rate is a value specified for a material or the like, and the standard is different depending on the country, the value corresponding to the standard may be used.

[Embodiment 2]

When the relationship between the length d of the bottom straight portion and the depth H of the wave is set on the relationship line obtained by the equation (7) or the equation (9), the depth of the wave is set in a non-stage manner corresponding to the length d of the bottom straight portion. H, other aspects of manufacturing and construction are complicated, and the cost is increased. Therefore, it is practical to make the depth H of the wave correspond to the length d of the bottom straight portion.

For example, as shown in Fig. 9, a method of setting the depth H of the wave for every 1000 mm of the length d of the bottom straight portion can be employed.

In the case of a gradual change, the buckling damage that is less prone to sharp damage than the sharp buckling damage can be said to be more suitable as a destructive state of the structure, so it is set in the manner of undulating damage first, that is, in the "buckling load" It is preferable to set in the area of the >floating load" (set in a manner that does not enter the region of "buckling load <floating load"). The phase relationship line in Figure 9 is set as such. The depth H of each range wave of the bottom straight portion length d is specifically shown as follows.

The length of the bottom straight portion is in the range of 2000 mm to 3000 mm, and the depth H of the wave is 84 mm.

The length of the bottom straight portion is in the range of 3000 mm to 4000 mm, and the depth of the wave is deep. Degree H is 114 mm

The length of the bottom straight portion is in the range of 4000 mm to 5000 mm, and the depth H of the wave is 142 mm.

As described above, the depth H of the wave is deepened stepwise along the shape of the relationship line as shown in Fig. 9, thereby obtaining the above various effects, and the non-buckling damage is caused by the premature failure, thereby preventing the occurrence of sharp breakage.

The setting procedure when the depth H of the wave is set according to the method of FIG. 9 is (i) to (iii).

(i) setting a relative deviation of the total buckling pressure p _cr when the bottom of the corrugated steel plate groove is buckling by the horizontal action on the two side wall faces, and the equivalent stress p _y when the outer pressure is lowered by the external pressure The first relationship line of the depth H of the wave at the length d of the bottom straight portion (the relationship line of "buckling load = deferred load" shown in Fig. 9).

(ii) Based on the first relationship line, the second relationship line of the depth H of the wave is set for each specific section of the length d of the bottom straight portion (in the example of FIG. 9 , the interval is set every 1000 mm) (FIG. 9) The staged relationship line shown).

(iii) The depth H of the wave with respect to the length d of the bottom straight portion is set based on the second relationship line.

The region (one region) located on the upper side with respect to the first relationship line is a region of "buckling load > declining load", and the region located at the lower side with respect to the first relationship line (the other region) becomes "buckling load < fall load" region. The second relationship line is set in the region of "buckling load > declining load", and the depth H of the wave is fixed regardless of the change in the length d of the bottom straight portion in one interval.

In addition, when the depth H of the wave is set in stages, as shown in FIG. 12, Consider the relationship between “buckling load/safety rate=falling load”. In other words, the phased second relationship line may be set in a region between the relationship between the "buckling load = the undulating load" and the relationship between the "buckling load/safety rate = the undulating load".

Industrial availability

The present invention can be utilized in a design method of a corrugated steel sheet for designing a corrugated steel sheet having a U-shaped corrugated steel sheet groove formed of a corrugated steel sheet (in particular, a corrugated shape thereof), and using a corrugation according to the design method thereof A corrugated steel plate groove formed by a steel plate.

1‧‧‧Corrugated steel tube

1a‧‧‧Corrugated steel plate

2‧‧‧Walls on both sides

3‧‧‧ bottom

Sectional area of each width B of A‧‧‧ corrugated steel plate mm ²

A‧‧‧ amplitude of wave (=H/2)mm

B‧‧‧Width of corrugated steel sheet (length in the direction orthogonal to the wave of corrugated steel sheet groove) mm

d, d', d"‧‧‧ (corrugated steel plate groove) bottom straight length mm

E‧‧‧elastic coefficient N/mm ²

H‧‧‧ depth of depth mm

Sectional secondary moment of each width B of the I‧‧‧ corrugated steel plate mm ⁴

p _cr ‧‧‧all buckling corresponding pressure N/mm ²

T‧‧‧thickness mm

σ _y ‧‧‧Reducing stress N/mm ²

Fig. 1 is an explanatory view for explaining a method of designing a corrugated steel sheet groove according to an embodiment of the present invention, wherein (a) shows a state in which an external pressure level acts on the outer surface of the side wall of both sides of the corrugated steel sheet groove, and (b) shows the whole. The buckling corresponding pressure p _cr acts on the bottom straight portion of the corrugated steel sheet groove by the above external pressure, and (c) shows the state in which the relief stress σ _y acts on the bottom straight portion.

Fig. 2 is a view showing a state in which a compression load acts on a straight portion at the bottom of the groove of the corrugated steel sheet of Fig. 1 (b) or (c).

Fig. 3 is a perspective view showing the appearance of a body portion of the corrugated steel sheet groove of Fig. 1.

Fig. 4 is a view showing a wave shape of a cross section of a corrugated steel sheet constituting the groove of the corrugated steel sheet.

Fig. 5 is a view showing an approximate wave shape when the wave shape of the corrugated steel sheet of Fig. 2 is approximated by a sinusoidal wave shape as an embodiment of the method for designing a corrugated steel sheet groove according to the present invention.

Fig. 6 is a view for explaining the method of deriving the equation (4) of the sectional area A of the width B of the corrugated steel sheet.

Fig. 7 is a view for explaining the method of deriving the equation (6) of I (cross-sectional secondary moment) of the corrugated steel sheet.

Fig. 8 is a graph showing the relationship of the formula (8), and shows the length of the bottom straight portion and the depth H of the wave when the wave shape of the corrugated steel sheet is designed according to the design method of the corrugated steel sheet groove according to the present invention. A diagram showing an example of the relationship between (the amplitude of the wave a is twice).

Fig. 9 is a view showing the correspondence between the correspondence relationship between the depth d of the bottom straight portion shown in the diagram of Fig. 8 and the depth H of the wave, and the corresponding relationship between the depth H of the wave and the stepwise change of the length d of the bottom straight portion. Illustration of the example.

Fig. 10 is a view showing a main cross-sectional shape of a wide-area construction of a type 1 corrugated steel sheet, and (a) and (b) are different types.

Fig. 11 is a view showing a sectional shape which is widely used as a groove for a type 2 corrugated steel sheet.

Fig. 12 is a view showing an example of the relationship between the length d of the bottom straight portion shown in Fig. 8 and the depth H of the wave (twice the amplitude a of the wave), and is an example in which the relationship of the safety ratio is considered.

1‧‧‧Corrugated steel tube

2‧‧‧Walls on both sides

3‧‧‧ bottom

D‧‧‧(the corrugated steel plate groove) bottom straight length mm

D'‧‧‧ (corrugated steel plate groove) bottom straight length mm

d"‧‧‧ (corrugated steel plate groove) bottom straight length mm

Claims (8)

A method for designing a corrugated steel sheet characterized by: designing a wave shape of the corrugated steel sheet groove formed by a corrugated steel sheet having a corrugated steel sheet having a wave shape having a depth H of a wave and having a U-shaped bottom straight portion length d at both side walls and a bottom portion When the bottom of the groove of the corrugated steel sheet is equal to the bottom line by means of a horizontally acting external pressure on the outer surfaces of the two side walls and the buckling corresponding pressure p _cr is equal to the falling stress σ _y at the time of the fall The depth H of the wave of the length d. The method of designing a corrugated steel sheet according to claim 1, wherein the depth of the wave with respect to the length d of the bottom straight portion is set in such a manner that the total buckling pressure p _cr shown in the following formula (1) is equal to the relief stress σ _y . H, where d: bottom straight line length mm p _cr : total buckling corresponding pressure N/mm ² E: elastic coefficient N/mm ² σ _y : fall stress N/mm ² B: width of corrugated steel plate (= with corrugated steel plate Length of the wave in the orthogonal direction of the groove) mm I: section secondary moment of each width B of the corrugated steel sheet mm ⁴ A: sectional area per width B of the corrugated steel sheet mm ² A method of designing a corrugated steel sheet according to claim 2, wherein a depth H of a wave with respect to a length d of the bottom straight portion is set according to the following formula (7), wherein a: amplitude of the wave (= H/2) mm t: plate Thick mm A method of designing a corrugated steel sheet according to claim 2, wherein a depth H of a wave with respect to a length d of the bottom straight portion is set according to the following formula (9), wherein a: amplitude of the wave (= H/2) mm A method for designing a corrugated steel sheet characterized by: designing a wave shape of the corrugated steel sheet groove formed by a corrugated steel sheet having a corrugated steel sheet having a wave shape having a depth H of a wave and having a U-shaped bottom straight portion length d at both side walls and a bottom portion When the bottom of the groove of the corrugated steel sheet is bent by the external pressure acting on the outer surfaces of the two side walls, the total buckling pressure p _{cr is} equal to the bottom straight line when the relief stress σ _y is lowered by the external pressure. The relationship between the length d of the portion and the depth H of the wave is such that the depth H of the wave with respect to the length d of the bottom straight portion is set such that the buckling load is greater than the load. The method for designing a corrugated steel sheet according to claim 5, comprising the steps of: setting a total buckling corresponding pressure p _cr when the bottom of the corrugated steel plate groove is buckling by externally acting on the outer surfaces of the two side walls; The relief stress σ _y when the external pressure is lowered, becomes the first relationship line of the depth H of the wave with respect to the length d of the bottom straight portion; and the length of the straight portion with respect to the bottom is set for each specific section based on the first relationship line The depth H of the wave of d is a second relationship line that changes stepwise; and the depth H of the wave with respect to the length d of the bottom straight portion is set based on the second relationship line; and the region is one of the first relationship lines The region where the buckling load is greater than the load of the load, the region where the undulation load is greater than the buckling load relative to the other region of the first relationship line; the second relationship line is set in the above region, regardless of the bottom line in the specific interval The variation of the length d of the part is fixed, and the depth H of the wave is fixed. A method for designing a corrugated steel sheet characterized by: designing a wave shape of the corrugated steel sheet groove formed by a corrugated steel sheet having a corrugated steel sheet having a wave shape having a depth H of a wave and having a U-shaped bottom straight portion length d at both side walls and a bottom portion When, the depth H of the wave with respect to the length d of the bottom straight portion is set according to the following formula (8), where a: wave amplitude (=H/2) mm t: plate thickness mm d: bottom straight line length mm E: Elastic coefficient N/mm ² σ _y : Falling stress N/mm ² A corrugated steel plate groove characterized by: a wave depth H of the corrugated steel plate in a groove of a corrugated steel plate having a wave-shaped corrugated steel plate having a wave depth of H and a bottom portion having a U-shaped bottom straight portion length d The size determined according to the design method of the corrugated steel sheet according to any one of claims 1 to 7.