Structure design device, structure design method, and structure construction method

Abstract

To provide a structural design device that reduces a calculation load in optimization calculation for a structural design process.SOLUTION: A structural design device includes: a cross-section information generation unit that generates cross-section information for a structure of a design object; a determination unit that determines whether or not a structure having the generated cross-section information satisfies a condition of a preset evaluation item; and an optimum solution determination unit that evaluates, after the determination by the determination unit is completed, a preset object function and determines an optimum solution for the cross-section information. The evaluation item consists of a design verification item for the structure and a prior-evaluation item that should be considered when designing the structure. The determination unit sequentially determines whether the evaluation items are satisfied and completes the determination when it determines that the evaluation item is not satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a structure design device, a structure design method, and a structure construction method using the same. [Background technology]

[0002] Steel bridge design is carried out by searching for optimal conditions (for example, cross-sectional dimensions that minimize steel weight) while satisfying various design verification conditions. When design conditions become complex and the number of design variables increases, the search range for solutions becomes exponentially larger, so performing the structural design process manually may not always be optimal. For this reason, optimization calculations that automate the structural design process have been proposed.

[0003] For example, Patent Document 1 discloses a method for quickly determining the optimal solution for the placement or cross-section of structural members that make up the framework of a building by reliably evolving chromosome information based on combining the best groups contained in each pair of chromosome information to generate new chromosome information. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-110298 [Non-patent literature]

[0005] [Non-Patent Document 1] Japan Bridge Construction Association, "Composite Girder Design Examples and Explanations - Road Signs, November 2017 Edition," February 2018 Summary of the Invention [Problem to be solved by the invention]

[0006] In optimization calculations for the design process of a structure, the cross-sectional information for the structure is set, the design is verified, the design results are evaluated, and the cross-sectional information is modified repeatedly to search for the cross-sectional information that optimizes the evaluation value of the objective function. In this case, by increasing the optimization variables (for example, the number of cross-sections to be optimized, the number of digits, etc.), more complex structures can be designed. Furthermore, the wider the search range for a solution, the higher the chance of finding a precise optimal solution. However, the number of iterative calculations required to find the optimal solution increases. Furthermore, because numerical analysis is required for each design verification, the computational load for the entire optimization calculation can be enormous.

[0007] Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to provide a structure design device, a structure design method, and a structure construction method using the same, which are capable of reducing the calculation load in optimization calculations in the design process of a structure. [Means for solving the problem]

[0008] In order to solve the above problems, according to one aspect of the present invention, there is provided a structure design device comprising: a cross-sectional information generation unit that generates cross-sectional information of a structure that is the object of design; a judgment unit that judges whether or not a structure having the generated cross-sectional information satisfies the conditions of predetermined evaluation items; and an optimal solution determination unit that evaluates a predetermined objective function after the judgment by the judgment unit is completed, and determines an optimal solution for the cross-sectional information, wherein the evaluation items consist of design verification items for the structure and pre-evaluation items that should be considered when designing the structure, and the judgment unit sequentially judges whether or not the evaluation items are satisfied, and terminates the judgment when it determines that the evaluation items are not satisfied.

[0009] The optimum solution determination unit may determine, as the optimum solution, the cross-sectional information that minimizes an objective function that represents the construction cost of the structure.

[0010] The structure design device may search for an optimal solution using an evolutionary computing method. That is, using the evolutionary computing method, the cross-sectional information generation unit may generate cross-sectional information, and the optimal solution determination unit may evaluate an objective function to determine an optimal solution for the cross-sectional information.

[0011] The determination unit may perform the determination in order of the evaluation items with the least calculation load.

[0012] Alternatively, the determination unit may determine the evaluation items in an order that is set based on the calculation load of the evaluation items and the ease of satisfying the conditions so as to reduce the overall calculation load.

[0013] In addition, in order to solve the above-mentioned problems, according to another aspect of the present invention, there is provided a structure design method including a cross-sectional information generation step of generating cross-sectional information of a structure to be designed, a judgment step of judging whether or not the structure having the generated cross-sectional information satisfies the conditions of predetermined evaluation items, and an optimal solution determination step of evaluating a predetermined objective function after completion of the judgment step to determine an optimal solution for the cross-sectional information, wherein in the judgment step, it is sequentially judged whether or not the evaluation items consisting of the design verification items of the structure and the pre-evaluation items to be considered when designing the structure are satisfied, and the judgment is terminated when it is determined that the evaluation items are not satisfied.

[0014] Furthermore, in order to solve the above-mentioned problems, according to another aspect of the present invention, there is provided a method for constructing a structure, which includes a cross-sectional information determination step for determining cross-sectional information of a structure to be designed using the above-mentioned structure design method, a design step for designing a structure having the determined cross-sectional information, and a construction step for constructing the designed structure. [Effects of the Invention]

[0015] As described above, according to the present invention, it is possible to reduce the calculation load in optimization calculations for the design process of a structure. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a block diagram showing an example of the configuration of a structure design apparatus according to an embodiment of the present invention; [Figure 2] 10 is a flowchart illustrating an example of a structure design method according to the present embodiment. [Figure 3] FIG. 1 is a cross-sectional view showing a schematic structure of a girder bridge. [Figure 4] This is a plan view of a lattice analysis model of a girder bridge. [Figure 5] An explanatory diagram of the main girder. [Figure 6] 10 is a graph showing a comparison result of calculation time for cross-section information as an example. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant explanations will be omitted.

[0018] [1. Structure design device] First, the configuration of a structure design apparatus 100 according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the configuration of the structure design apparatus 100 according to this embodiment.

[0019] The structure design device 100 according to this embodiment is a device that performs optimization calculations for the design process of structures such as bridges. When designing structures such as bridges, a design review is performed to verify technical suitability by comparing the design with the design conditions and design standards specified in specifications and the like. The items for the design review are predetermined. In addition, although not included as design review items, designers generally take into account certain conditions when designing a structure. For example, these conditions include "the relationship between plate thicknesses is determined by the magnitude of the applied bending moment" and "the width of the lower flange is greater than the width of the upper flange" in the case of a composite girder bridge. Based on these conditions considered by the designer, candidates for cross-sectional information of the structure that clearly do not result in an optimal solution are eliminated.

[0020] In consideration of such a structure design process, the structure design device 100 according to this embodiment sets, as evaluation items, items for the design verification of the structure and pre-evaluation items to be considered when designing the structure when searching for optimal cross-sectional information of the structure. The evaluation items are then evaluated in order, and an evaluation value is calculated using an objective function that evaluates the optimality of the cross-sectional information of the structure. At this time, if an item that does not satisfy the conditions occurs, the evaluation of the evaluation item is terminated at that point, and an evaluation value of the objective function is calculated. As a result, for cross-sectional information of a structure that is unlikely to be the optimal solution, the cross-sectional information is evaluated without evaluating all evaluation items, thereby reducing the calculation load of the entire optimization calculation.

[0021] As shown in FIG. 1, a structure design device 100 according to this embodiment includes a cross-sectional information generating unit 110, a determining unit 120, an optimal solution determining unit 130, and a storage unit 140.

[0022] (Cross section information generation section) The cross-sectional information generating unit 110 generates cross-sectional information for the structure to be designed. The cross-sectional information for a structure is information about the dimensions and materials of the main members that make up the structure. For example, in the case of a bridge, the dimensions and materials of the main girders for each block are generated as cross-sectional information. Here, one block refers to one member that makes up the structure and whose cross-sectional dimensions and material are constant along the member axis. The cross-sectional information generating unit 110 generates cross-sectional information about the dimensions and materials for n blocks for which an optimal solution is sought.

[0023] The cross-section information generation unit 110 automatically generates optimal cross-section information candidates that satisfy the specifications of the structure to be designed within a pre-specified dimensional range. Here, the optimization calculation for the structure design process can be performed using, for example, an evolutionary computing method. Evolutionary computing is a method for searching for optimization variables that minimize an objective function based on data manipulation (mutation, crossover) following the theory of biological evolution. Specific examples include differential evolution (DE) and genetic algorithm (GA). When the optimization variable searched for in evolutionary computing is the cross-section information of the structure, the cross-section information generation unit 110 performs a process of generating optimal cross-section information candidates by data manipulation, among the processes executed in evolutionary computing. The cross-section information generation unit 110 outputs the generated cross-section information to the determination unit 120.

[0024] (Judgment Department) The determination unit 120 determines whether or not the structure having the cross-sectional information generated by the cross-sectional information generation unit 110 satisfies the conditions of the preset evaluation items. The evaluation items are set in advance and consist of design verification items for the structure and pre-evaluation items that should be considered when designing the structure.

[0025] The design verification items for a structure are items used to confirm whether the required functions of the structure are met. For example, the design verification items for a bridge include stress verification, deflection verification, fatigue verification, minimum plate thickness requirements, etc. (See, for example, Non-Patent Document 1). Pre-assessment items are not design verification items, but are items set based on empirical rules in structural design, to confirm whether conditions that would not apply if the cross-sectional information were optimal are met. Pre-assessment items may be set manually, for example, by a designer. For example, the pre-assessment items for a bridge include plate thickness magnitude relationships based on bending moment magnitude relationships, minimum plate thickness requirements for the webs and flanges of I-shaped main girders, flange width, etc.

[0026] The determination unit 120 evaluates these evaluation items one by one. When the determination unit 120 has finished evaluating all evaluation items, it proceeds to processing by the optimal solution determination unit 130. Note that when an evaluation item that does not satisfy the conditions occurs, the determination unit 120 ends the evaluation of the evaluation items at that point and proceeds to processing by the optimal solution determination unit 130. A cross-sectional shape candidate that has an evaluation item that does not satisfy the conditions is unlikely to be the optimal solution. For this reason, even if evaluation of evaluation items, including design verification items, is performed, it is likely to be unnecessary. Therefore, when an evaluation item that does not satisfy the conditions occurs, unnecessary calculations can be omitted by ending the evaluation of the evaluation item at that point.

[0027] The evaluation order of the evaluation items can be set arbitrarily. In this case, the evaluation order of the evaluation items may be changed so as to reduce the overall calculation load. For example, if there is variation in the calculation load of the process for evaluating the evaluation items, the evaluation may be performed in order of decreasing calculation load of the evaluation items. In this way, if the evaluation of an evaluation item is terminated midway, the evaluation of an evaluation item with a higher calculation load can be omitted.

[0028] Alternatively, the evaluation order of the evaluation items may be set based on the computational load of the evaluation items and the ease of satisfying the conditions so as to reduce the overall computational load. For example, for an evaluation item that satisfies the conditions in almost all cases, even if the computational load is relatively low, the evaluation result of that evaluation item is unlikely to cause the evaluation process of the evaluation item by the determination unit 120 to be interrupted. In contrast, for an evaluation item that frequently fails to satisfy the conditions, even if the computational load is relatively high, the evaluation result of that evaluation item is likely to cause the evaluation process of the evaluation item by the determination unit 120 to be interrupted. In this case, evaluating evaluation items with relatively high computational loads first can allow the calculation of cross-sectional shape candidates that are unlikely to be the optimal solution to be completed earlier. Therefore, by setting the evaluation order of the evaluation items taking into account not only the computational load of the evaluation items but also the ease of satisfying the conditions of the evaluation items, the evaluation of evaluation items for cross-sectional shape candidates that are unlikely to be the optimal solution can be completed earlier.

[0029] (Optimal solution determination section) After the determination unit 120 completes the determination, the optimal solution determination unit 130 evaluates a preset objective function to determine an optimal solution for the cross-sectional information. When the optimization calculation for the design process of a structure is performed using an evolutionary computing method, the optimal solution determination unit 130 performs a process of evaluating the cross-sectional information using the objective function, among the processes executed in the evolutionary computing, to identify an optimal solution. The objective function is a function that evaluates the optimality of the cross-sectional information of the structure and can be appropriately set, for example, by a designer. For example, when there are multiple shapes of each component of a structure that are acceptable in the specifications, if the optimal shape is one that can reduce the construction costs required for manufacturing the structure, an objective function that represents the construction costs of the structure can be set, and the optimal solution determination unit 130 determines the cross-sectional information that minimizes the evaluation value of the objective function as the optimal solution.

[0030] When the optimal solution determination unit 130 determines that the candidate cross-sectional information is not optimal cross-sectional information, it instructs the cross-sectional information generation unit 110 to generate new cross-sectional information. On the other hand, when the evaluation value of the objective function is minimized, it outputs the cross-sectional information as the optimal solution (i.e., optimal cross-sectional information).

[0031] (Storage part) The storage unit 140 is a storage unit that stores information (initial setting information) required to carry out the structure design method according to this embodiment. Information related to the structure to be designed, information required to search for an optimal solution, etc. are recorded in the storage unit 140. The cross-section information generation unit 110, the judgment unit 120, and the optimal solution determination unit 130 each perform processing while referring to the initial setting information recorded in the storage unit 140.

[0032] The structure design device 100 according to this embodiment has been described above. The structure design device 100 may be configured by an information processing device such as a computer including a hardware processor such as a CPU (Central Processing Unit) and memories such as RAM (Random Access Memory) and ROM (Read Only Memory). In this case, various calculations are performed by the hardware processor executing programs stored in the memory of the information processing device.

[0033] It is also possible to create a program for realizing each function of the cross-section information generation unit 110, the judgment unit 120, and the optimal solution determination unit 130 of the structure design device 100 shown in FIG. 1 and install it on a computer or the like. The computer executes the program implemented by the CPU (Central Processing Unit) or the like of the computer, thereby realizing each function of the structure design device 100. It is also possible to provide a computer-readable recording medium on which such a program is stored. Examples of the recording medium include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. The above program may also be distributed, for example, via a network, without using a recording medium.

[0034] [2. Structure design method] Next, a structure design method according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a flowchart showing an example of the structure design method according to this embodiment. The structure design method according to this embodiment is executed by the structure design device 100 described above.

[0035] In the following, as a specific example, a structural design method will be described using the case of finding an optimal solution for the cross-sectional information of the main girder 20 of a simple plate girder bridge (hereinafter referred to as "girder bridge") shown in Figures 3 and 4. Figure 3 is a cross-sectional view that schematically shows the structure of the girder bridge 1. Figure 4 is a plan view of a lattice analysis model of the girder bridge 1, showing the positions of the main girder 20 and cross girder 30. Note that in the lattice analysis model, members other than the main girder 20 and cross girder 30 (secondary members) are also set, but the secondary members are omitted from Figure 4. The cross-sectional view shown in Figure 3 corresponds to the cross section taken along the AA cutting line in Figure 4. In Figures 3 and 4, the width direction of the girder bridge 1 is the X direction, the length direction of the girder bridge 1 is the Y direction, and the height direction of the girder bridge 1 is the Z direction.

[0036] The girder bridge 1 shown in FIG. 3 supports a deck slab 10 in the width direction by four main girders 20 (G1, G2, G3, and G4). The main girders 20 are members with an I-shaped cross section and extend along the Y direction. As shown in FIG. 5, the main girders 20 consist of an upper flange 21, a lower flange 23, and a web 25. As shown in FIG. 4, multiple cross girders 30 (S1, S2, C1, C2, C3, C4, and C5) are installed along the length of the girder bridge 1 at predetermined intervals so as to intersect perpendicularly with the main girders 20. The cross girders 30 installed at both ends of the girder bridge 1 in the length direction are particularly referred to as end cross girders (S1 and S2). Optimal cross-sectional information for the main girders 20 of such a girder bridge 1 is obtained using the structure design method according to this embodiment.

[0037] In the following description, differential evolution (DE), which is one type of evolutionary computation, is used to search for optimal cross-sectional information, but the present invention is not limited to this example and other optimization computation methods may also be used.

[0038] (S10: Initial setting) First, information required for carrying out the structure design method according to this embodiment (initial setting information) is set in advance (S10). The designer sets the initial setting information based on the specifications of the structure to be designed, etc. The initial setting information includes information about the girder bridge 1 and information required for searching for an optimal solution. Information about the girder bridge 1 includes, for example, the dimensions of the girder bridge 1 to be designed, the number of main girders 20 and cross girders 30, the dimensions and material of the main girders 20, etc. Information required for searching for an optimal solution includes, for example, the number of individuals, the number of generations, and the upper limit of the number of iterative calculations when using a differential evolution method. The initial setting information is recorded, for example, in the storage unit 140 of the structure design device 100.

[0039] (S20: Cross-section information generation step) Next, the cross-sectional information generating unit 110 generates cross-sectional information of the structure to be designed (S20). The cross-sectional information generating unit 110 refers to the storage unit 140 and automatically generates candidates for optimal cross-sectional information that meets the specifications of the structure to be designed within a pre-specified dimensional range. For example, the cross-sectional information of the main girder 20 shown in FIG. 3 includes the plate thickness t of the upper flange 21 of n blocks for which an optimal solution is to be found. u , width b of upper flange 21 u , thickness t of bottom flange 23 l , width b of the lower flange 23 l , web thickness t w , girder height H, material F y The cross-section information generating unit 110 outputs the generated cross-section information to the determining unit 120.

[0040] (S30 to S50: Judgment steps) The determination unit 120 determines whether or not a structure having cross-sectional information generated by the cross-sectional information generation unit 110 satisfies the conditions of preset evaluation items. The evaluation items are set in advance and recorded in the storage unit 140. The evaluation items consist of design verification items for the structure and pre-evaluation items set by the designer to be considered when designing the structure, and the determination unit 120 evaluates the set evaluation items one by one in sequence.

[0041] The determination unit 120 performs an evaluation for each evaluation item (S30) and determines whether the conditions of the evaluation item are met (S40). For example, suppose that three items, stress check, deflection check, and fatigue check, are set as design check items for the girder bridge 1, and three items, plate thickness magnitude relationship based on bending moment magnitude relationship, minimum plate thickness conditions for the web and flange of the main girder, and flange width, are set as pre-evaluation items.

[0042] At this time, the determination unit 120 performs a stress check by calculating stress (S30) and determining whether the stress meets the allowable value (S40), a deflection check by calculating deflection (S30) and determining whether the deflection meets the allowable value (S40), and a fatigue check by calculating the stress range of the main structure (S30) and determining whether the allowable value for the number of repeated loadings is met (S40).In addition, with regard to the pre-evaluation items, the determination unit 120 calculates the bending moment (S30) and evaluates the plate thickness based on the bending moment (S40), compares it with the minimum plate thickness of the web and upper and lower flanges of the main girder (S30) and evaluates it (S40), and compares the upper and lower flange widths of the main girder with the allowable value (S30) and evaluates it (S40).

[0043] The determination unit 120 repeats the processes of steps S30 to S50 while the conditions of the evaluation items are met (S40: YES) and until evaluation of all evaluation items is completed (S50: NO). Then, when evaluation of all evaluation items is completed (S50: YES), the process proceeds to step S60.

[0044] On the other hand, if an evaluation item that does not satisfy the conditions occurs (S40: NO), the judgment unit 120 ends the evaluation of the evaluation item at that point and proceeds to the processing of step S60. This is because a cross-sectional shape candidate that has an evaluation item that does not satisfy the conditions is unlikely to be the optimal solution, and even if evaluation of the evaluation item is continued, it is likely to be unnecessary. If an evaluation item that does not satisfy the conditions occurs, by ending the evaluation of the evaluation item at that point, unnecessary calculations can be omitted.

[0045] The evaluation order of the evaluation items in the judgment step can be set arbitrarily. In this case, the evaluation order of the evaluation items may be changed so as to reduce the overall calculation load. For example, evaluation may be performed in order from the evaluation items with the lowest calculation load. In this way, if the evaluation of an evaluation item is terminated midway, the evaluation of an evaluation item with a higher calculation load can be omitted. Generally, the calculation load of design review items is higher than that of pre-evaluation items. For this reason, the pre-evaluation items may be evaluated first, and then the design review items may be evaluated.

[0046] Alternatively, the evaluation order of the evaluation items may be set based on the computational load of the evaluation items and the ease of satisfying the conditions so as to reduce the overall computational load. For example, by evaluating an evaluation item that is relatively computationally heavy but frequently fails to satisfy the conditions before an evaluation item that is relatively computationally light but satisfies the conditions in almost all cases, the evaluation of evaluation items for cross-sectional shape candidates that are unlikely to be the optimal solution can be completed earlier, thereby reducing the overall computational load. Therefore, for example, the evaluation order of the evaluation items may be set in descending order of the computational load of the evaluation items and the ease of satisfying the conditions, and the determination step may be executed.

[0047] (S60~S80: Optimal solution determination step) When the determination step is completed, the optimal solution determination unit 130 evaluates the cross-sectional information using a preset objective function to determine the optimal solution for the cross-sectional information. The objective function is a function that evaluates the optimality of the cross-sectional information of the structure, and can be set appropriately by the designer. For example, the objective function V shown in the following equation (1) may be set.

[0048]

number

[0049] Here, when the number of blocks is i, w i is the steel weight of block i, G iis the material coefficient of block i. The material coefficient is set according to the steel type, and the higher the cost, the larger the value. In other words, the objective function V in the above formula (1) represents the construction cost required to manufacture a structure based on the cross-sectional information, and if the cross-sectional information that minimizes the construction cost is the optimal solution, then such an objective function should be set.

[0050] P is a penalty, and its value is determined depending on whether the judgment step is terminated halfway. For example, if evaluation of all evaluation items has been completed, P=1 is set, and if the judgment step is terminated halfway and there are evaluation items that have not been evaluated, a value greater than 1 (for example, P=100) is set for P. By increasing the value of the penalty P when the judgment step is terminated halfway, the evaluation value of the objective function V is prevented from becoming the minimum, and the cross-sectional information in question is prevented from being determined as the optimal solution.

[0051] The optimal solution determination unit 130 calculates an evaluation value of the objective function V (S60) and determines whether the evaluation value has reached a minimum (S70). If the evaluation value does not satisfy a preset convergence determination condition and the number of iterative calculations is less than an upper limit, the optimal solution determination unit 130 determines that the evaluation value is not yet minimum (S70: NO) and instructs the cross-section information generation unit 110 to generate new cross-section information. The convergence determination condition may be, for example, that the evaluation value of the objective function is not updated for a certain number of iterative calculations (e.g., 10 times).

[0052] The processes of steps S20 to S60 are repeated until the convergence determination condition is satisfied or the number of repeated calculations reaches the upper limit. When the evaluation value satisfies the convergence determination condition or the number of repeated calculations reaches the upper limit, the optimal solution determination unit 130 determines that the current evaluation value is the minimum (S70: YES), and determines the cross-section information at this time as the optimal solution (S80) and outputs it.

[0053] For example, the optimal solution determination unit 130 may output the optimal solution to an output device (not shown) connected to the structure design device 100 directly or via a network. The output device may be, for example, a display device such as a monitor, a printer, or the like. The optimal solution determination unit 130 may also output the optimal solution to an external terminal connected to the structure design device 100 directly or via a network. Furthermore, the optimal solution determination unit 130 may record the optimal solution on a recording medium, or may store the optimal solution in the cloud.

[0054] In the above explanation, one piece of cross-sectional information is output as the optimum solution when the evaluation value satisfies the convergence judgment condition or when the number of repeated calculations reaches the upper limit, but multiple pieces of cross-sectional information with the same evaluation value may also be output as candidates for the optimum cross-sectional information. Cross-sectional information that has the same evaluation value as when the optimum solution is obtained is also considered to be appropriate as cross-sectional information for the structure.

[0055] For example, if the convergence determination condition is set such that the evaluation value of the objective function has not been updated in the last 10 times (number of iterative calculations), the current cross-section information determined as the optimal solution and nine pieces of cross-section information when the evaluation value has not been updated may be selected as candidates for the optimal cross-section information. Also, if the convergence determination condition is not satisfied but the number of iterative calculations reaches the upper limit, and the same evaluation value as the current one continues from the current one back, the current cross-section information determined as the optimal solution and the cross-section information from which the same evaluation value as the current one was obtained may be selected as candidates for the optimal cross-section information.

[0056] When optimal cross-sectional information candidates are output, the designer, for example, can select the cross-sectional information to be used in the design of the structure from these candidates, taking into consideration the constructability of the structure, etc.

[0057] The structure design method according to this embodiment has been described above. According to the structure design method according to this embodiment, when an evaluation item that does not satisfy the conditions occurs in the design of a structure, evaluation of the evaluation item is terminated at that point, and evaluation using the objective function is performed. This makes it possible to omit unnecessary calculations, and reduces the calculation load of the entire optimization calculation. As a result, it becomes possible to obtain optimal cross-sectional information for the structure in a shorter time.

[0058] The cross-sectional information of a structure obtained using the structure design method according to this embodiment can be used in the design of the structure. The structure design method according to this embodiment determines the cross-sectional information of the structure to be designed, designs a structure having the determined cross-sectional information, and constructs the designed structure. By designing and constructing a structure in this manner, the time required for design can be shortened, and as a result, the time required for the overall construction of the structure can also be shortened. [Example]

[0059] The effectiveness of this invention was verified using the example of optimal design of the cross-sectional dimensions of the main girders of a steel plate girder bridge. The girder bridge to be designed was a simple composite plate girder bridge (span length 33 m, 4 main girders x 3 blocks) shown in Figures 3 to 5. Here, taking symmetry into consideration, the optimal solution was found for the cross-sectional information of the four blocks (G1B1, G1B2, G2B1, G2B2) shown in Figure 4.

[0060] The cross-sectional information includes the thickness of the upper flange of each block, t u , upper flange width b u , bottom flange thickness t l , bottom flange width b l , web thickness t w , girder height H, material F y For simplicity, the girder height is fixed at H = 1700 mm, and the width of the upper flange is b u and width of bottom flange b l is set to be the same for all blocks. Therefore, the optimization variables for the cross-sectional information are the width of the upper flange b u and width of bottom flange b l and the thickness of the upper flange for the four blocks, t u, bottom flange thickness t l , web thickness t w and material F y The total number of variables is 18, including the 16 variables listed above.

[0061] The optimization method used was differential evolution (DE). The number of individuals was 60, the number of generations was 500, and the upper limit of the number of iterations was 30,000. The search reference value for each variable was the dimensions of the original design example, and the search range was 0.5 to 1.5 times the search reference value. Material F y The search range was set to four steel types: SM490, SM570, SBHS400, and SBHS500. Note that no convergence criteria were set in this example.

[0062] The evaluation items were set as design verification items for girder bridges: stress verification, deflection verification, fatigue verification, and minimum plate thickness conditions. In addition, the following items (a) to (d) were set as pre-evaluation items.

[0063] (a) Flange thickness conditions (because the bending moment is larger in block B2 than in block B1 for all girders, the flange thickness of block B2 is also made larger than that of block B1) t u_G1B1 <t u_G1B2 , t l_G1B1 <t l_G1B2 t u_G2B1 <t u_G2B2 , t l_G2B1 <t l_G2B2 (b) Web thickness conditions (since the shear force is greater in block B1 than in block B2 in all girders, the web thickness of block B1 is also greater than that of block B2) t w_G1B1 >t u_G1B2 , t w_G1B1 >t l_G1B2 (c) Conditions for the width of the upper and lower flanges (in composite bridges, the width of the lower flange is usually made larger than the width of the upper flange). b u l ​(d) Relationship between flange width and girder height (usually, flange width is 1 / 5 to 1 / 3 of the girder height) H / 5 u <H / 3 H / 5 l <H / 3

[0064] The evaluation order of the evaluation items was as shown in Table 1 below. The objective function used was the above formula (1). The penalty for terminating the judgment step midway was set to P = 1,000,000.

[0065] [Table 1]

[0066] In this example, the calculation load was evaluated by calculation time. Figure 6 shows the calculation time when the structural design method of the present invention was used as an example, and the calculation time when all of the evaluation items shown in Table 1 above were evaluated as a comparative example. In the example, when evaluating the evaluation items shown in Table 1, the judgment step was terminated midway when the conditions for the evaluation item were not met. As a result, as shown in Figure 6, the calculation time in the example was reduced by about 70% compared to the comparative example. In this way, by using the structural design method of the present invention, calculation time can be reduced and optimal cross-sectional information for a structure can be obtained in a shorter time.

[0067] ​​In the evaluation order of the evaluation items shown in Table 1, stress verification, which has the highest computational load, is evaluated before deflection verification and fatigue verification. For example, deflection verification has a moderate computational load, but is an evaluation item that meets the conditions in almost all cases when the bridge span length is relatively short, such as the girder bridge designed in this example. Similarly, fatigue verification also has a moderate computational load, but is an evaluation item that meets the conditions in almost all cases when the bridge span length is relatively long, such as the girder bridge designed in this example, because stress fluctuations due to live loads are small. Therefore, the evaluation process of the evaluation items is unlikely to be interrupted by the evaluation results of deflection verification and fatigue verification. Therefore, it is believed that the overall computational load would be lower if deflection verification and fatigue verification were evaluated after stress verification, which has a high computational load, as in the calculation order shown in Table 1 above.

[0068] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention. [Explanation of symbols]

[0069] 1 girder bridge 10 Floor slab 20 Main digit 21 Upper flange 23 Lower flange 25 Web 30 crossbeam 100 Structure design equipment 110 Cross section information generation section 120 Judgment section 130 Optimal solution determination unit 140 Storage section

Claims

1. a cross-section information generating unit that generates cross-section information of a structure to be designed; a determination unit that determines whether or not a structure having the generated cross-sectional information satisfies a condition of a preset evaluation item; an optimal solution determination unit that evaluates a preset objective function and determines an optimal solution for cross-sectional information after the determination unit has completed; Equipped with The evaluation items consist of design verification items for the structure and pre-evaluation items to be considered when designing the structure, The determination unit sequentially determines whether the evaluation items are satisfied, and terminates the determination when it determines that the evaluation items are not satisfied.

2. 2. The structure design device according to claim 1, wherein the optimum solution determination unit determines, as the optimum solution, cross-sectional information that minimizes an objective function that represents a construction cost of the structure.

3. 3. The structure design device according to claim 1, wherein the cross-sectional information generation unit generates the cross-sectional information using an evolutionary computing method, and the optimal solution determination unit evaluates the objective function to determine an optimal solution for the cross-sectional information.

4. The structure design device according to claim 1 , wherein the determining unit performs the determination in order of the evaluation items with the smallest calculation load.

5. 3. The structure design device according to claim 1, wherein the determining unit determines the evaluation items in an order set to reduce the overall calculation load based on the calculation load of the evaluation items and ease of satisfying the conditions.

6. a cross-section information generating step of generating cross-section information of a structure to be designed; a determination step of determining whether or not a structure having the generated cross-sectional information satisfies a condition of a preset evaluation item; an optimal solution determination step of evaluating a preset objective function and determining an optimal solution for cross-sectional information after the determination step is completed; Including, In the judgment step, a structural design method is performed in which it is judged in sequence whether or not the evaluation items, which consist of design verification items for the structure and pre-evaluation items that should be considered when designing the structure, are satisfied, and the judgment is terminated when it is judged that the evaluation items are not satisfied.

7. a cross-sectional information determination step of determining cross-sectional information of a structure to be designed using the structure design method according to claim 6; a design step of designing a structure having the determined cross-sectional information; a construction step of constructing the designed structure; A method of constructing a structure, including:

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