Wooden building collapse simulation program

Abstract

To provide a wooden building collapse simulation program capable of performing highly accurate time-history response analysis of wooden buildings during an earthquake up to its collapse, with the analysis extended to include foundations and ground, so that the simulated behavior corresponds to the actual behavior of the building during an earthquake.SOLUTION: A wooden building collapse simulation program for causing a computer to perform a time-history response analysis of a wooden building during an earthquake up to its collapse, comprises: a step for calculating the stress acting on each spring using an element stiffness matrix corresponding to the type of spring in an analytical model, by a distinct element method, based on the information of the analytical model, which models the wooden building, and its foundation and ground by combining a plurality of nodes and a plurality of types of springs, and on the prerequisites for the time-history response analysis during an earthquake, both of which are stored in an input file; and a step for summing the stresses acting on all springs connected to each node.SELECTED DRAWING: Figure 41

Description

[Technical Field]

[0001] The present invention relates to a simulation program for simulating the collapse of a wooden building during an earthquake, which performs a time history response analysis of the wooden building up to its collapse. [Background technology]

[0002] The earthquake resistance of wooden buildings has attracted attention due to the extensive damage caused to existing wooden buildings in large-scale earthquakes, and research has begun to conduct full-scale shaking table tests of wooden buildings. However, full-scale shaking table tests have the problem of requiring enormous amounts of money, effort, and time.

[0003] Therefore, in recent years, coupled with the increasing performance of computers, time history response analysis of buildings has begun to be carried out by calculating and simulating the behavior of buildings during earthquakes using simulation programs.

[0004] In the past, time history response analysis of such buildings was generally performed using a simulation program that uses the finite element method (FEM), represented by the matrix method.

[0005] However, because the finite element method requires the calculation of an overall stiffness matrix, extreme nonlinearity must be taken into account in order to track collapse, and it is particularly difficult to process unbalanced forces in calculations in states where destruction has progressed to an extreme degree, such as the fracture of members (breakage of wood) or the development of cracks.In particular, with wooden buildings, the collapse limit can reach a large deformation range where the story drift angle exceeds 1 / 5 rad., and it has been extremely difficult to use a simulation program using the finite element method to accurately calculate and simulate the behavior of wooden buildings from a state where deformation has progressed to the point of collapse in a way that matches the behavior of actual buildings during an earthquake.

[0006] Therefore, Patent Document 1 below proposes using the Distinct Element Method (DEM), a non-continuum analysis method, to accurately simulate actual behavior during an earthquake, from a region of large deformation where destruction has progressed to collapse.Patent Document 1 describes a wooden building collapse simulation program that uses the Distinct Element Method to calculate the stress acting on each spring using an element stiffness matrix according to the type of spring in the analysis model, and adds up the stresses acting on all springs connected to each node, based on information from an analysis model that models a wooden building by combining multiple nodes and multiple types of springs and the prerequisites for time history response analysis during an earthquake. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-083813 Summary of the Invention [Problem to be solved by the invention]

[0008] The technology described in Patent Document 1 above models a wooden building built on a foundation and uses it as an analytical model for collapse simulation, so it is not possible to verify the safety of the foundation during an earthquake. Therefore, it is necessary to use a separate structural calculation program or the like.

[0009] Incidentally, most safety verifications of wooden building foundations are carried out based on the "Allowable Stress Design for Wooden Frame Construction Houses" (the so-called "Gray Book") published by the Japan Housing and Wood Technology Center. Therefore, the general structural calculation programs used for foundation safety verification perform structural calculations in accordance with this allowable stress design for wooden frame construction houses.

[0010] In structural calculations based on the allowable stress design of wooden frame houses, the safety of the foundation is verified based on the allowable strength of the walls of the wooden building. Therefore, although the foundation beams of the actual building are continuous beams, in the calculations, the foundation beams are replaced with simple beams. In this case, the bending moment is overcalculated, so the amount of rebar in the foundation is calculated to be more than necessary, and excessive foundation specifications are often required. This results in problems such as increased foundation costs and limited design freedom.

[0011] Based on the above, the inventors of the present application considered extending the analytical model of the collapse simulation program using the discrete element method described above to include the foundations and ground of wooden buildings. In other words, the time history response analysis of a wooden building during an earthquake leading up to its collapse is extended to include the foundations and ground, and is performed with high accuracy to match the actual behavior during an earthquake. This allows the foundation to be optimized according to the desired strength, which is expected to reduce foundation costs and increase the degree of freedom in building design.

[0012] Taking the above facts into consideration, the present invention aims to provide a simulation program for the collapse of wooden buildings that can extend the time history response analysis leading up to the collapse of wooden buildings during an earthquake to the foundation and ground, and can perform this analysis with high accuracy so as to match the actual behavior during an earthquake. [Means for solving the problem]

[0013] The first aspect of the present invention is a simulation program for simulating the collapse of a wooden building, which causes a computer to execute a time history response analysis of a wooden building leading up to its collapse during an earthquake. The program is characterized by having the following steps: calculating the stress acting on each spring using an element stiffness matrix corresponding to the type of spring in the analysis model using the distinct element method, based on information stored in an input file that combines multiple nodes and multiple types of springs to model the wooden building, its foundation, and the ground, and the prerequisites for the time history response analysis during an earthquake; and adding up the stresses acting on all springs connected to each node.

[0014] A first aspect of the wooden building collapse simulation program is a computer-implemented simulation program for performing a time history response analysis of a wooden building during an earthquake, up to the point of collapse. The program includes the steps of: calculating the stress acting on each spring using a distinct element method (DEM) based on information stored in an input file about an analytical model that combines multiple nodes and multiple types of springs to model the wooden building, its foundation, and the ground, and the assumptions for the time history response analysis during an earthquake; and summing the stresses acting on all springs connected to each node. This allows for accurate calculation and simulation of the behavior of a wooden building, its foundation, and the ground from a state of advanced deformation to collapse, which cannot be accurately simulated using conventional simulation programs such as the finite element method, so as to match the actual behavior of the building during an earthquake. As a result, the time history response analysis of a wooden building during an earthquake up to the point of collapse can be extended to the foundation and the ground, and can be performed with high accuracy to match the actual behavior during an earthquake.

[0015] In the second aspect of the present invention, a simulation program for simulating the collapse of a wooden building is provided, in the first aspect, in which the analytical model of the foundation and the ground is modeled by combining a plurality of nodes and a plurality of types of springs, including a foundation beam, an anchor bolt connecting the foundation beam to the wooden building, and a foundation reaction force acting on the foundation beam from the ground.

[0016] In the second aspect of the wooden building collapse simulation program, the analytical model of the foundation and ground is modeled using a combination of multiple nodes and multiple types of springs to represent the foundation beams, the anchor bolts connecting the foundation beams to the wooden building, and the foundation reaction force acting on the foundation beams from the ground. Therefore, rather than relying on conventional structural calculations based on the allowable stress design of wooden frame construction houses, the behavior of the foundation and ground can be accurately calculated and simulated using the distinct element method to match the behavior of actual buildings during earthquakes, thereby verifying the safety of the foundation. As a result, the foundation of a wooden building can be optimized.

[0017] A third aspect of the present invention relates to a simulation program for simulating the collapse of a wooden building, and is characterized in that, in the first or second aspect, the types of springs in the analysis model are modeled as being divided into elastic-plastic springs of the frame, elastic-plastic springs of the joints, elastic-plastic rotational springs of the joints, truss springs of the vertical and horizontal structural planes, compression brace springs, tension brace springs, elastic springs of the foundation beams, elastic springs of the anchor bolts connecting the foundation beams to the wooden building, and elastic springs of the foundation based on the foundation reaction force acting from the ground on the foundation beams, and the input file contains parameter information corresponding to the type of modeled springs, and the computer is caused to execute a step of determining the element stiffness matrix using this parameter information.

[0018] In the third aspect of the wooden building collapse simulation program, the springs in the analysis model are modeled as being divided into elastic-plastic springs of the frame, elastic-plastic springs of the joints, elastic-plastic rotational springs of the joints, truss springs of the vertical and horizontal structural planes, compression brace springs, tension brace springs, elastic springs of the foundation beams, elastic springs of the anchor bolts connecting the foundation beams to the wooden building, and elastic springs of the foundation based on the foundation reaction force acting from the ground on the foundation beams.The input file contains parameter information corresponding to the modeled spring types, and the computer is caused to execute the step of determining the element stiffness matrix using this parameter information.Therefore, in addition to the above-mentioned effects, the structural characteristics of wooden buildings built using the frame construction method are utilized, making it possible to perform calculations and simulations with even greater accuracy. [Effects of the Invention]

[0019] As described above, the wooden building collapse simulation program of the present invention can extend the time history response analysis leading up to the collapse of a wooden building during an earthquake to the foundation and ground, and can perform this analysis with high accuracy so as to match the actual behavior during an earthquake. [Brief explanation of the drawings]

[0020] [Figure 1] This is a conceptual diagram of a rock mass collapse simulation using the distinct element method. [Figure 2] FIG. 1 is an explanatory diagram of forces calculated using a conventional distinct element method. [Figure 3] This is a conceptual diagram of frame modeling. [Figure 4] FIG. 10 is an explanatory diagram of the restoring force characteristics used in the modeling of the embodiment. [Figure 5] 1 is a graph showing a skeleton curve used in the modeling of the above embodiment. [Figure 6] FIG. 1 is a conceptual diagram of modeling of a joint. [Figure 7] 10 is a graph showing the restoring force characteristics of an elastic-plastic spring used in the modeling of the embodiment. [Figure 8] 10 is a graph showing the restoring force characteristics of an elastic-plastic rotational spring used in the modeling of the embodiment. [Figure 9] This is a conceptual diagram of modeling of vertical structural planes. [Figure 10] FIG. 10 is an explanatory diagram of the restoring force characteristics used in modeling the vertical structural plane. [Figure 11] This is a conceptual diagram of modeling a brace. [Figure 12] 1 is a conceptual diagram of modeling a building including a foundation and soil. [Figure 13] (A) is a graph showing the skeleton curve used to model the foundation and ground, and (B) is a graph showing the Q-δ relationship used to model the foundation and ground. [Figure 14] FIG. 2 is an explanatory diagram showing a flow of program calculation according to an embodiment of the present invention. [Figure 15] FIG. 10 is an explanatory diagram showing the flow of creating an analysis model file. [Figure 16] An explanatory diagram showing the format of a framework file. [Figure 17] FIG. 2 is an explanatory diagram of each part of the framework model. [Figure 18] FIG. 2 is an explanatory diagram showing the format of a configuration file. [Figure 19] FIG. 2 is an explanatory diagram of each part of the structural surface model. [Figure 20] FIG. 10 is an explanatory diagram showing the format of a diagonal file. [Figure 21] FIG. 10 is an explanatory diagram of each part of the brace model. [Figure 22] FIG. 2 is an explanatory diagram showing the format of a basic file. [Figure 23] 1A and 1B are explanatory diagrams of each part of the foundation and ground model, where FIG. 1A is a perspective view of the foundation, and FIG. 1B is a longitudinal cross-sectional view of the foundation. [Figure 24] FIG. 2 is an explanatory diagram showing the format of a weight file. [Figure 25] FIG. 10 is an explanatory diagram for explaining weight designation of an analysis model. [Figure 26] FIG. 10 is a diagram illustrating an example of a confirmation screen for an analysis model. [Figure 27] FIG. 10 is a diagram showing an example of a detailed setting window for the appearance of an analysis model. [Figure 28] FIG. 2 is an explanatory diagram showing the format of a parameter file. [Figure 29] FIG. 10 is an explanatory diagram showing a format for setting a shaft assembly spring in a parameter file. [Figure 30] FIG. 10 is an explanatory diagram showing a format for setting a joint spring in a parameter file. [Figure 31] FIG. 10 is an explanatory diagram showing a format for setting a rotation spring in a parameter file. [Figure 32] FIG. 10 is an explanatory diagram showing a format for setting a structural spring in a parameter file. [Figure 33] FIG. 10 is an explanatory diagram showing a format for setting a diagonal spring in a parameter file. [Figure 34] FIG. 10 is an explanatory diagram showing a format for setting foundation beam springs in a parameter file. [Figure 35] FIG. 10 is an explanatory diagram showing a format for setting anchor springs in a parameter file. [Figure 36] FIG. 10 is an explanatory diagram showing a format for setting ground springs in a parameter file. [Figure 37] 10A and 10B are explanatory diagrams showing an image of each external force input mode. [Figure 38] FIG. 10 is an explanatory diagram showing the format of an external force file when inputting seismic waves. [Figure 39] FIG. 10 is an explanatory diagram showing the format of pushover analysis 1 of an external force file. [Figure 40] FIG. 10 is an explanatory diagram showing the format of pushover analysis 2 of the external force file. [Figure 41] FIG. 2 is an explanatory diagram showing the format of a calculation condition file. [Figure 42] 10 is a flowchart showing an example of the flow of main calculations executed by a calculation program. [Figure 43] 10 is a flowchart showing an example of the flow of a stress vector calculation process which is part of the main calculations executed by the calculation program. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, the wooden building collapse simulation program according to this embodiment will be described with reference to FIGS.

[0022] [Distinct Element Method] First, an outline of the distinct element method, which is the basic theory of the program according to the present invention, will be explained. As mentioned in the background art, the program of the present invention uses the distinct element method as its basic theory, instead of the finite element method that has been commonly used in structural analysis in the field of conventional architecture, as an analytical method that can accurately track the time history response analysis of wooden buildings during earthquakes up to their collapse. This method calculates the stress acting on each element individually and can determine acceleration, velocity, displacement increments, etc. without the need to solve the overall stiffness matrix. The distinct element method is a "discontinuum analysis method (a method for calculating the behavior of discrete objects)" originally developed to calculate the collapse of soil and rock masses, as shown in Figure 1, so it is possible to naturally analyze the behavior of buildings from large deformation ranges to collapse.

[0023] The distinct element method falls into the category of dynamic explicit methods among numerical analysis methods, and conventional analytical methods using the distinct element method only calculate the repulsive and frictional forces when two objects come into contact, as shown in Figure 2. For this reason, structural elements commonly used in the structural analysis of buildings, such as beam elements and truss elements, did not exist. As a result, there are few examples of research using the distinct element method in the field of architecture, and currently there are no time history response analysis tools using the distinct element method for wooden buildings.

[0024] (Numerical analysis method) Next, the numerical analysis method of this distinct element method will be explained. Similar to the finite element method, the analytical model is constructed by combining nodes and springs. The displacement and stress vectors in the global coordinate system at time t-1 between nodes 1 and 2 at both ends of a spring i are given by (Equation 1) below, the displacement and stress vectors in the member coordinate system for spring i's displacement vector [Di]t-1 and stress vector [Fi]t-1 at time t-1 are given by (Equation 2) below, and the increment of each vector between Δt from time t-1 to t is given by (Equation 3) below. If there is a displacement increment of [Δdi]t at nodes 1 and 2 at both ends of spring i due to the action of an external force at time t-1, then [fi]t can be calculated for spring i with element stiffness matrix [Ki]t and damping matrix [Ci]t using (Equation 4) below.

[0025]

number

[0026]

number

[0027]

number

[0028]

number

[0029] Here, if the coordinate transformation matrix from the global coordinate system to the component coordinate system is [Ti]t, then the above (Equation 4) can be expressed as the following (Equation 5).

[0030]

number

[0031] The above formula 5 is calculated for each spring to calculate the stress vector [fi]t1, [fi]t2 at each node. These stress vectors are added for all springs connected to a certain node A to calculate the stress vector [FA]t acting on node A (formula 6).

[0032]

number

[0033] The stress vector calculated by this formula is numerically integrated using Newmark's β method (average acceleration method β=1 / 4) to calculate the acceleration [aA]t, velocity [vA]t, and displacement increment [ΔDA]t at time t (Formula 7).

[0034]

number

[0035] By performing the above calculations for each element and each time, the response of the entire model to an external force is calculated. In this way, the distinct element method is characterized by the fact that it calculates stress individually for each element without solving the overall stiffness matrix, which is not found in conventional finite element methods. In other words, because balance is maintained by the propagation of stress between elements as time progresses, it is possible to analyze unbalanced forces and behavior after collapse without any special processing.

[0036] (Construction of analytical model) Next, we will explain the method for modeling each component of a wooden building. In this invention, when modeling a wooden building constructed using the framework construction method, each component and its joints are modeled by dividing them into "frame," "joint," "vertical structural planes and vertical structural planes," "braces," and "foundation and ground."

[0037] (Frame modeling) First, the modeling of the framework will be explained. As shown in Figure 3, framework members such as columns, beams, girders, window sills, and lintels were modeled using elastic-plastic rotational springs (plastic hinges) + elastic beam elements to take into account breakage of the members. The restoring force characteristics (hysteresis characteristics) that represent the relationship between the input load and deformation of this model were based on the hysteresis rule shown in Figure 4. Here, the bending strength of the members was set based on experimental results and literature, and the maximum bending moment was determined according to the section modulus. Furthermore, as shown in Figure 5, this skeleton curve is defined by the M-θ relationship, and when the maximum bending moment (Mp) is exceeded, the moment begins to decrease. When the bending moment reaches a rotation angle of zero, the component is considered to have broken, and the rotation spring between the components is changed to a pin connection. By setting it up in this way, it became possible to express in the analysis the breakage of through columns and the breakage of cross members at the joints of columns with hanging walls.

[0038] (Modeling of joints) Next, modeling of the joint will be described. The joints referred to here include joints between frames. As shown in Figure 6, each joint was modeled using an elastic-plastic rotational spring + elastic-plastic spring (rigid in shear). The restoring force characteristics of the compression / tension elastic-plastic spring (hereafter referred to as the joint spring) were one-sided elastic + one-sided slip type shown in Figure 7, and this skeleton curve was set based on experimental data. The hysteresis curve of the elastic-plastic rotation spring was determined from literature and other sources using the slip type shown in Figure 8. This elastic-plastic rotation spring was set to act independently in the directions of the strong axis and weak axis.

[0039] (Modeling of vertical and horizontal structural surfaces) Next, modeling of the vertical and horizontal structural planes will be explained. As shown in Fig. 9, the shear force of vertical structural components such as walls, hanging walls, and spandrel walls was modeled by replacing braces with truss springs. The restoring force characteristics were calculated using the bilinear + slip type hysteresis rule shown in Fig. 10. In addition, horizontal structural components such as floors and roofs were also modeled by replacing braces with truss elements, and the restoring force characteristics were also modeled using a bilinear + slip type hysteresis rule.The skeleton curves shown in the figure were set with reference to literature and experimental results.

[0040] (Modeling of braces) Next, modeling of the braces will be explained. As shown in Figure 11, the brace members were modeled by placing two truss elements, one for compression and one for tension, per brace. The asymmetric horizontal restoring force of the brace shear wall is expressed by setting the springs of the compression brace so that they do not act on the force in the tension direction, and the springs of the tension brace so that they do not act on the springs in the compression direction. In addition, the joint points between the compression brace and the frame are set as horizontal members, so the thrust behavior of the beams and girders caused by the compression brace is modeled. Note that the restoring force characteristics employ a bilinear + slip type hysteresis rule, the same as for the springs of the structural face (see Figure 10).

[0041] In modeling each component, the average integral method was used for numerical integration, and damping was set to be proportional to instantaneous stiffness and to 0% on a downward gradient.

[0042] (Foundation and ground modeling) Next, the modeling of the foundation and ground will be explained. 12 is a conceptual diagram of a wooden building 10, its foundation 20, and ground 30 modeled by combining multiple nodes and multiple types of springs. The foundation 20 and ground 30 are modeled by combining multiple nodes and multiple types of springs, including foundation beams extending in a specific section, anchor bolts connecting the foundation beams to the wooden building 10, and foundation reaction forces acting on the foundation beams from the ground 30. In this embodiment, a case will be described in which a continuous footing (see FIG. 22(B)) having a footing portion and a rising portion is used as the foundation of the wooden building 10.

[0043] (Foundation beam spring) As shown in Figure 12, the foundation beams of the foundation 20 were modeled by placing foundation beam springs 22. The foundation beam springs 22 were modeled using elastic foundation beam elements. Therefore, the foundation beam springs 22 were modeled as elastic springs. The skeleton curve of the foundation 20 is a linear skeleton curve because it is modeled as an elastic spring. Here, this skeleton curve is defined by the PD relationship between load [P] and displacement [D], as shown in Figure 13(A). Furthermore, the Q-δ relationship between the story shear force [Q] and story deformation [δ] of each story also shows a linear relationship, as shown in Figure 13(B).

[0044] The reason why modeling using (plastic hinge) + elastic beam elements, as in the modeling of the frame members described above, is not performed is because the main purpose of the present invention is to perform a time history response analysis of the wooden building 10 up to the collapse thereof, and to apply this to the calculation of the allowable stress of the wooden building 10. From this perspective, since it is not necessary to consider the collapse of the foundation 20 and the ground 30, the foundation beam springs 22 are modeled as elastic springs. Therefore, when considering the collapse of the foundation 20 and the ground 30, the foundation beam springs 22 may be modeled as elasto-plastic springs, as in the modeling of the frame members.

[0045] (Anchor spring) The anchor bolts, which serve as the joints connecting the foundation beams and the framework (foundation), were modeled by placing anchor springs 24. As an example, the anchor springs 24 are configured as elastic springs (rigid in shear). Therefore, in modeling, the anchor springs 24 are set as compression and tension elastic springs. The relationship between the skeleton curve of the anchor springs 24 and the inter-story displacement of the story shear force of each story also shows a linear relationship, as in the modeling of the framework members (see Figures 13(A) and 13(B)).

[0046] The anchor springs 24 were not modeled as elasto-plastic springs for the same reason as the frame members. That is, the anchor springs 24 were modeled as elastic springs because it was not necessary to consider the collapse of the foundation 20 and the ground 30. However, the anchor springs 24 may also be modeled as elasto-plastic springs. In this case, the restoring force characteristics of the compression and tension anchor springs 24 can be of the one-side elasticity + one-side slip type shown in Figure 7, similar to the joint springs. In addition, in FIG. 12, a vertical load F transmitted to the anchor spring 24 is shown.

[0047] (Ground spring) The foundation reaction force acting on the foundation beam from the ground 30 was modeled by placing ground springs 32 at predetermined intervals along the extension direction of the foundation beam element (foundation beam spring 22). These ground springs 32 can be considered as the joint connecting the foundation 20 (foundation beam) and the ground 30. As an example, the ground springs 32 are configured as elastic springs (rigid in shear). Therefore, in the modeling, the ground springs 32 are set as compression and tension elastic springs. The relationship between the skeleton curve of the ground springs 32 and the inter-story displacement of the story shear force of each story also shows a linear relationship, as in the modeling of the frame members (see Figures 13(A) and 13(B)).

[0048] The reason why the ground spring 32 was not modeled as an elasto-plastic spring is the same as that for the frame members. That is, since it is not necessary to consider the collapse of the foundation 20 and the ground 30, the anchor spring 24 was modeled as an elastic spring. However, the ground spring 32 may also be modeled as an elasto-plastic spring. In this case, the restoring force characteristics of the compression and tension ground spring 32 can be of the one-sided elasticity + one-sided slip type shown in Figure 7, similar to the joint spring. [Example]

[0049] A wooden building collapse simulation program according to an embodiment of the present invention will be described below with reference to the drawings.

[0050] (Calculation overview) First, an overview of a program according to an embodiment of the present invention will be described with reference to Fig. 14. The calculation program (calc.exe) shown in Fig. 12 is a wooden building collapse simulation program exemplified as an embodiment of the present invention, and gui.exe in the figure is an interface program that serves as support software for the calculation program. As shown in Fig. 14, this calculation program (calc.exe) is a wooden building collapse simulation program that causes a computer to execute predetermined calculations at specified time intervals (= Δt0) based on information stored in four input files (see Table 1): an analysis model file (test.mod), a parameter file (parm.csv), an external force condition file (load.csv), and a calculation condition file (default.ini), which will be described later. The program then outputs three output files (see Table 2): a trajectory file (out.trj), a calculation result file (detaout.csv), and an analysis continuation file (cont.mod).

[0051] The four input files are explained below. The analysis model file is a file containing information about the elements and springs of the analysis model. The parameter file is a file containing parameter information for various springs. The external force condition file is a file containing external force conditions such as input seismic waves and pushover position. The calculation condition file is a file containing external force calculation conditions such as the number of calculations, increments, and viewpoint.

[0052] The three output files are explained below. The trajectory file is a file that stores time history data for the coordinates of each element of the analysis model, and can be viewed with gui.exe. The calculation result file stores the story shear force of each floor of the analysis model, the absolute displacement of specific points on each floor, and the characteristic values ​​of elements specified for monitoring. The analysis continuation file is a file that contains information about the elements and springs of the analysis model after calculation. By recalculating using this file as the input file, continuous external force input is possible.

[0053] [Table 1]

[0054] [Table 2]

[0055] In addition, the interface program (gui.exe) is an interface program for the calculation program (calc.exe) that causes the computer to perform tasks such as assisting in the creation of the input file, the analysis model file described below, visualizing the analysis model as a three-dimensional (3D) image, and visualizing the time history data of the coordinates of each element of the analysis model stored in the output file, the trajectory file, as an animation.

[0056] [Analysis model file] As shown in Figure 15, the analysis model file is created by the interface program (gui.exe) from five CSV files (comma-separated text files)—frame file (frame.csv), structural surface file (wall.csv), brace file (brace.csv), foundation file (footing.csv), and weight file (weight.csv)—which contain information such as the coordinates of the component ends of the analysis model. The file also contains information about the elements and springs of the analysis model. As mentioned above, the analysis model of the present invention is modeled separately for the "frame," "joints," "vertical structural surfaces and vertical structural surfaces," "braces," and "foundation and ground." Therefore, various information, such as the coordinates of the component ends of each model (described below), can be input from the five CSV files created as the analysis model file, and visualized as an analysis model using the interface program (gui.exe). Note that information about the joints between the frame members is input into the frame file (frame.csv), and information about the joints of the foundation beams is input into the foundation file (footing.csv).

[0057] (Frame file) The frame file (frame.csv) is a CSV file with a format consisting of 13 columns, each corresponding to a frame member, as shown in Figure 16. This file contains information about the frame and the joints between the frame members of the analysis model. As shown in Table 3, the first column is where the type of frame is entered; 1 is entered for beams, girders, and 2 is entered for columns, such as posts and beams. The second through fourth columns are where the absolute coordinates of end 1 of the frame member are entered in XYZ order. The fifth through seventh columns are where the absolute coordinates of end 2 of the frame member are entered in XYZ order. The eighth column is where the win / loss of the joint for end 1 of the frame member is entered; 1 is entered for a win and 0 for a loss. If there is no joint at the end, 1 is entered. The ninth column is where the win / loss of end 2 of the frame member is entered, similar to the eighth column. The 10th column is where the cross-sectional width of the frame member is entered, the 11th column is where the cross-sectional composition (height) of the frame member is entered, the 12th column is where the parameter ID (spring number) of the frame member is entered, and the 13th column is where the parameter ID of the joints at both ends of the frame member is entered. These parameter IDs must be the same as the parameter ID numbers specified in the parameter file described below. All coordinates are in meters and are entered in center-to-center coordinates.

[0058] [Table 3]

[0059] If the coordinates of the ends of the components are the same, the interface program (gui.exe) will automatically generate the joints in the analysis model. In this case, the "losing" component is entered using center-to-center coordinates, so it is automatically offset by the width of the opposing component. Also, although this is a format for entering coordinates in 3D, 2D simulations are also possible by setting all Y coordinates (see Figure 17) to 0.

[0060] (Structural file) As shown in Figure 18, the structural surface file (wall.csv) is a CSV file in a format consisting of seven columns, each corresponding to one of the structural surfaces enclosed by battens, etc., and is a file into which information regarding the vertical and horizontal structural surfaces of the analysis model is input. As shown in Table 4, columns 1 to 3 are where the absolute coordinates of end 1 of each structural surface (see Figure 19) are input in XYZ order, and columns 4 to 6 are where the absolute coordinates of end 2 of each structural surface (see Figure 19) are input in XYZ order. As with the frame file, all coordinates are in meters and are input in center-to-center coordinates. The seventh column is where the structural surface parameter ID is input. This parameter ID must be the same as the ID number specified in the parameter file described below. In addition, the ends of the frame members are required at the ends of the structural face, and if there is an opening in the wall, the horizontal members above and below the opening (window sill, lintel) are added to the frame file, and the hanging walls and waist walls are added to the structural face file.

[0061] [Table 4]

[0062] (Sujigai File) The brace file (brace.csv) is a CSV file with a format consisting of seven columns, each corresponding to a brace member, as shown in Figure 20. It is a file into which information about the compression braces and tension braces of the analysis model is input. As shown in Table 5, columns 1 to 3 are where the absolute coordinates of end 1 of the brace member (see Figure 21) are entered in XYZ order, and columns 4 to 6 are where the absolute coordinates of end 2 of the brace member (see Figure 21) are entered in XYZ order. In the brace file, all coordinates are entered in meters, using center-to-center coordinates. The seventh column is where the parameter ID of the brace member is entered; this parameter ID must be the same as the ID number specified in the parameter file, described below. In addition, the ends of the diagonal members also require the ends of the frame members, and when diagonal members are entered in a cross-hatched manner, they are entered in two lines as if there were a separate half-diagonal member.

[0063] [Table 5]

[0064] (Basic file) The footing file (footing.csv) is a CSV file in a format consisting of seven columns, with each row corresponding to one of the foundation beams in a given section, as shown in Figure 22. This file contains information about the foundation beams of the analysis model, the joints between the foundation beams and anchor bolts, and the joints between the foundation beams and the foundation reaction forces acting from the ground.

[0065] Here, Fig. 23(A) is a perspective view of the foundation 20 of the wooden building 10 shown in Fig. 12, and Fig. 23(B) is a longitudinal cross-sectional view of the foundation 20. As shown in Figs. 22(A) and 22(B), the foundation 20 of this embodiment is configured as a continuous footing. The continuous footing has a footing portion buried in the ground and a rising portion erected on the footing portion. The footing portion is reinforced by a lattice-shaped reinforcement structure constructed with horizontally extending base reinforcement and horizontal reinforcing bars (reference numbers omitted) perpendicular to the base reinforcement. The rising portion is reinforced by a lattice-shaped reinforcement structure constructed with stirrups extending vertically perpendicular to the base reinforcement, horizontal main reinforcement bars connected to the upper and lower ends of the stirrups, and horizontal reinforcing bars connected to the stirrups between the upper and lower main reinforcement bars. In this embodiment, the rectangular beam-shaped portion of the foundation 20, excluding the left and right ends of the footing in the width direction, is modeled as a foundation beam element. In Figure 22(B), the rectangular cross section of the modeled foundation beam element is shown as region S1. The width W1 and height H1 of region S are input as the width and height of the foundation beam element, respectively, in the foundation parameter file described later (Table 14).

[0066] As shown in Table 6, the first to third columns are where the absolute coordinates of end 1 of the foundation beam (see Figure 23(A)) are input in XYZ order, and the fourth to sixth columns are where the absolute coordinates of end 2 of the foundation beam (see Figure 23(A)) are input in XYZ order. The seventh column is where the parameter ID (spring number) of the foundation beam is input. The parameter ID entered in the seventh column must be the same as the parameter ID number specified in the parameter file described below. All coordinates are in meters and are entered as center-to-center coordinates.

[0067] [Table 6]

[0068] (Heavyweight file) The weight file (weight.csv) is a CSV file in a format that allows input of up to five columns, as shown in Figure 24 and Table 7. The first line is the number of floors in the analysis model, the second line is the height of each floor in the analysis model, and the third line is the weight of each layer in the analysis model. The first column of the second row is the GL (ground level) of the foundation (h0 in Figure 25), and from the second column onwards, the floor levels of each floor are entered in meters, starting with the second floor floor level (h1 in Figure 25), the third floor floor level (not shown), etc., and the last column is where the level of the rafter (h2 in Figure 25) is entered. As shown in Figure 25, the third row is the section where the equivalent mass in kN units is entered when the analytical model is replaced with a skewer-shaped structure with each floor at the center. The first column is the weight of the lower half of the first floor plus the weight of the foundation, and the last column is the weight of the upper half of the top floor plus the weight of the roof truss. The weight entered here is divided by the number of elements present at that height and distributed evenly.

[0069] [Table 7]

[0070] As described above, when the five CSV files - the frame file (frame.csv), structural surface file (wall.csv), brace file (brace.csv), foundation file (footing.csv), and weight file (weight.csv) - are input, the aforementioned interface program (gui.exe) is launched and, by performing the prescribed operations, information such as the absolute coordinates of each of the aforementioned models input into each file is read, and as shown in Figure 26, it can be automatically displayed as a 3D (dimensional) image, and the analysis model can be saved as an analysis model file.

[0071] In addition, the interface program (gui.exe) according to this embodiment allows the user to visually check the analysis model on the confirmation screen by operating the mouse, Ctrl button, buttons on the screen, etc. Not only can the user change the appearance of the analysis model (see Figure 26), but as shown in Figure 27, the program allows the user to change the appearance of the analysis model, the transmittance of the walls, the position of the light source, the number of meshes in the ground (see Figure 25), the relative position display, etc.

[0072] [Parameter file] Next, the parameter file will be described. As shown in Figure 28, the parameter file (parm.csv) is a CSV file in which each line corresponds to one of the springs to be replaced when modeling in the analysis model, and the first column is assigned a parameter ID for each spring to be replaced (for example, for each specification when walls of different specifications are mixed). Then, in the second column, according to the modeling method described above, numbers from 1 to 9 are entered according to the type of spring to be modeled for each member, joint, etc., as shown in Table 8, and from the third column onwards, various parameters that differ depending on the type of spring entered in the second column are entered across multiple columns. The input parameters for each type of spring will be explained below.

[0073] [Table 8]

[0074] (Spring setting for frame members) When the spring type is a frame spring, that is, when inputting parameters for frame members such as columns, beams, girders, sills, and lintels into the parameter file, the second column is entered as a frame spring, as shown in Figure 29 and Table 9. Since frame members are modeled using elasto-plastic rotational springs (plastic hinges) and elastic beam elements, as mentioned above, the spring parameters are entered as follows: the Young's modulus (longitudinal elastic modulus) of the frame member [kN / m2 = 10-6 GPa] in the third column, the moment of inertia [m4] of the frame member (for example, if the frame member is a beam, enter the width and then the thickness) in the fourth and fifth columns, the maximum bending moment "kNm" (Mp in Figure 5) in the sixth and seventh columns, and the cross-sectional area [m2] of the frame member in the eighth column (see Table 9).

[0075] [Table 9]

[0076] (Spring settings for joints) When the spring type is a joint spring, that is, when inputting joint parameters into the parameter file, as mentioned above, the joint is modeled as an elastic-plastic rotational spring + an elastic-plastic spring (rigid against shear) (= joint spring), so the parameters are input separately as a joint spring (joint tension spring) and a rotational spring.

[0077] As shown in Figure 30 and Table 10, the parameters of the elastic-plastic spring of the joint are entered in the second column as 2, which represents the joint spring of the joint, in the third to fifth columns the first to third order stiffness [kN / m] of the restoring force characteristics shown in Figure 7 are entered, and in the sixth and seventh columns the inflection points D1 and D2 [m] of the skeleton curve are entered (see Figure 7).

[0078] [Table 10]

[0079] As shown in Figure 30 and Table 11, the parameters of the rotational spring of the joint are entered in the second column as 3, which represents the rotational spring of the joint, in the third to fifth columns as the first to third order stiffnesses [kN / m] of the restoring force characteristics shown in Figure 8, and in the sixth and seventh columns as the inflection points D1 and D2 [m] of the skeleton curve (see Figure 8).

[0080] [Table 11]

[0081] (Spring settings for structural components) If the spring type is a structural plane spring, that is, if parameters for a vertical or horizontal structural plane are entered in the parameter file, the number 4, representing a structural plane spring, is entered in the second column. As mentioned above, a vertical or horizontal structural plane is modeled by replacing braces with truss elements, so as shown in Figure 32 and Table 12, the loads P1 to P4 [kN] at the break points of the restoring force characteristics shown in Figure 10 are entered in the third to sixth columns, the displacements D1 to D4 [m] at the break points of the restoring force characteristics are entered in the seventh to tenth columns, and the damping constant of the spring is entered in the eleventh column.

[0082] [Table 12]

[0083] The parameter information for this structural spring is used in calculations after automatically correcting the dimensions and angles for the two brace replacement springs, so the load-deformation relationship (bilinear + slip type restoring force characteristics shown in Figure 10) for the structural surface with dimensions of 1P (0.91 m) x 3P (2.73 m) is determined from experimental results, etc., and the input values ​​for the loads P1 to P4, displacements D1 to D4, etc. are entered as parameters.

[0084] (Brace spring settings) If the spring type is a diagonal brace spring, that is, when entering parameters for a diagonal brace member in the parameter file, as mentioned above, the diagonal brace spring is modeled by placing two truss elements, one for compression and one for tension, assuming that the spring for a compression diagonal brace does not act on forces in the tensile direction, and the spring for a tension diagonal brace does not act on springs in the compression direction, so one diagonal brace member is input as a tension diagonal brace spring and a compression diagonal brace spring separately. Also, since tension diagonal braces and compression diagonal braces are modeled as a pair, the parameter ID must be assigned so that the tension diagonal brace ID (e.g., 501) + 100 becomes the compression diagonal brace ID (e.g., 601).

[0085] When entering parameters for tension brace springs in the parameter file, the second column should contain 5, which represents tension brace, and when entering parameters for compression brace springs, the second column should contain 6, which represents compression brace.

[0086] As shown in Figure 33 and Table 13, the diagonal springs are modeled by replacing the braces with truss elements in the same way as the structural springs, so the loads P1 to P4 [kN] at the break points of the restoring force characteristics shown in Figure 10 are entered in columns 3 to 6, the displacements D1 to D4 [m] at the break points of the restoring force characteristics are entered in columns 7 to 10, and the damping constant of the spring is entered in column 11. As with the structural springs, the load-deformation relationship of the brace springs (bilinear + slip type restoring force characteristics shown in Figure 10) for the structural brace springs with dimensions of 1P (0.91 m) x 3P (2.73 m) is determined from experimental results and input as a parameter.

[0087] [Table 13]

[0088] (Foundation beam spring settings) When the spring type is a foundation beam spring, i.e., when inputting the parameters of the foundation beam element into the parameter file, the second column is filled with 7, representing the foundation beam spring, as shown in Figure 34 and Table 14. Furthermore, as spring parameters, the Young's modulus (longitudinal elastic modulus) of the frame member [kN / m2 = 10-6 GPa] is input in the third column, and the second moment of area [m4] of the foundation beam is input in the fourth and fifth columns (e.g., in the order of width and height). The width of the foundation beam here corresponds to the width W1 of region S1 shown in Figure 23(B). The height of the foundation beam corresponds to the width H1 of region S1 shown in Figure 23(B). The maximum bending moment "kNm" (Mp in Figure 5) is input in the seventh column. Note that this maximum bending moment is the maximum bending moment when the foundation beam is modeled as an elasto-plastic spring. In this embodiment, the frame members are modeled using elastic beam elements (elastic springs), so the parameters in the seventh column are not taken into account in the calculations. The values ​​in the seventh column can be used when modeling the foundation beams as elastic-plastic springs. The eighth column is a format for inputting the cross-sectional area [m2] of the foundation beam (see also Table 9). The cross-sectional area of ​​the foundation beam here corresponds to the area of ​​region S1 shown in Figure 23(B).

[0089] [Table 14]

[0090] (Anchor spring setting) When the spring type is an anchor spring, that is, when inputting parameters of an anchor bolt element into a parameter file, as shown in FIG. 35 and Table 15, the second column is filled with 8, representing the anchor spring; the third to fifth columns are filled with the first- to third-order stiffnesses [kN / m] of the restoring force characteristics shown in FIG. 7; and the sixth and seventh columns are filled with the inflection points D1 and D2 [m] of the skeleton curve (see FIG. 7). Note that the first- to third-order stiffnesses entered in the third to fifth columns and the inflection points D1 and D2 entered in the sixth and seventh columns are the first- to third-order stiffnesses and inflection points when the anchor spring is modeled as an elasto-plastic spring. In this embodiment, the anchor spring is modeled as an elastic spring, so the relationship between the load input to the member and the displacement is linear (see FIGS. 13(A) and 13(B)). Therefore, the parameters in the third to seventh columns are not taken into account in the calculation. The values ​​in columns 3 to 7 can be used when modeling the anchor spring as an elastic-plastic spring.

[0091] [Table 15]

[0092] (Ground spring settings) When the type of spring is a ground spring, that is, when inputting parameters of a ground element into a parameter file, as shown in FIG. 36 and Table 16, the number 9 representing the ground spring is input in the second column, the first to third order stiffnesses [kN / m] of the restoring force characteristics shown in FIG. 7 are input in the third to fifth columns, and the inflection points D1 and D2 [m] of the skeleton curve are input in the sixth and seventh columns (see FIG. 7). Note that the first to third order stiffnesses input in the third to fifth columns and the inflection points D1 and D2 input in the sixth and seventh columns are the first to third order stiffnesses and inflection points when the ground spring is modeled as an elasto-plastic spring. In this embodiment, the ground spring is modeled as an elastic spring, so the relationship between the load input to the member and the displacement is linear (see FIGS. 13(A) and 13(B)). Therefore, the parameters in the third to seventh columns are not taken into account in the calculation. The values ​​in columns 3 to 7 can be used when modeling the anchor spring as an elastic-plastic spring.

[0093] [Table 16]

[0094] [External force condition file] Next, the external force condition file will be described. The calculation program (calc.exe) according to this embodiment is programmed to be able to execute three modes, "seismic wave input," "pushover analysis 1," and "pushover analysis 2," which differ in the way seismic forces are applied to the analysis model. The "seismic wave input" mode, as shown in Figure 37(a), is a mode in which a forced disturbance is input to all elements at ground level. The "pushover analysis 1" mode, as shown in Figure 37(b), is a mode in which the elements at ground level are fixed and forced displacement is applied in the horizontal direction to all elements at a certain height of the analysis model. The "pushover analysis 2" mode, as shown in Figure 37(c), is a mode in which the elements at ground level are fixed and horizontal gravitational acceleration is applied to all elements of the analysis model.

[0095] To accommodate these modes, the external force condition file (load.csv) contains the above three modes. There are three input formats for inputting information on external forces such as seismic waves from CSV files: "Seismic Wave Input," "Pushover Analysis 1," and "Pushover Analysis 2." As shown in Figure 38, the format for "Seismic Wave Input" is as follows: the first row is where you input the X-axis seismic wave, the second row is where you input the Y-axis seismic wave, and the third row is where you input the Z-axis seismic wave. As shown in Table 17, the first column is where you input a number corresponding to each mode (operation) for selecting the input format. For "Seismic Wave Input," 1 is input; for "Pushover Analysis 1," 2 is input; for "Pushover Analysis 2," 3 is input; and for "Fixed," 0 is input. Note that this "Fixed" mode is a mode in which no seismic force is applied.

[0096] [Table 17]

[0097] The second column contains the name of the input seismic wave time history file (a file in which the displacement and deformation time history is entered in one column), the third column contains the frequency of the seismic wave time history file entered in the second column in [Hz], and the fourth column contains the unit of the numerical values ​​entered in the seismic wave time history file as a multiplier for [m]. For example, 0.01 is entered for [cm], 0.001 for [mm], and 1.0 for [m]. The fifth column is the part where the input magnification, which is the magnification for amplifying seismic waves, is entered. If a negative value is entered here, the disturbance input will be in the opposite positive and negative directions (opposite phase).

[0098] As shown in Figure 39, the format for "Pushover Analysis 1" is where the X-direction force is input in the first row, the Y-direction force in the second row, and the Z-direction force in the third row. As shown in Table 18, the first column is where numbers corresponding to each mode for selecting the input format are input, just like the "Seismic Wave Input" format, and "2" is input to select "Pushover Analysis 1."

[0099] [Table 18]

[0100] The second and third columns are left blank, the height of the force application point is entered in [m] in the fourth column, and the force application speed, which is the speed of the forced displacement, is entered in [m / sec] in the fifth column. If a negative value is entered here, the force will be applied in the opposite direction.

[0101] The format for "Pushover Analysis 2," like "Pushover Analysis 1," is shown in Figure 40. The first row is where you enter the X-direction force, the second row is where you enter the Y-direction force, and the third row is where you enter the Z-direction force. As shown in Table 19, the first column is where you enter "3" to select "Pushover Analysis 2," columns 2 to 4 are left blank, the fifth column is where you enter the height of the force application point in [m], and the fifth column is where you enter the acceleration of the horizontal force to be applied to the analysis model in [G]. The value entered here specifies how many times the magnitude of the horizontal force to be applied to the analysis model is the gravitational acceleration of 1 [G] that is reached after one second when gradually increasing from 0 [G]. Entering a negative value will apply a force in the opposite direction.

[0102] [Table 19]

[0103] [Calculation condition file] Next, the calculation condition file will be described. The calculation conditions file (default.ini) is a file that is input in a CSV file format consisting of two lines, as shown in Figure 41. The first line stores the calculation conditions information, and the second line stores the viewpoint information when viewing the analysis model with the interface program (gui.exe) mentioned above. This calculation conditions file stores the calculation conditions information and viewpoint information set in advance, and can be used by the user by editing and correcting the necessary parts using software that can edit text files, such as an editor or Notepad.

[0104] The first column of this CSV file stores the number of calculations to be performed by the calculation program (calc.exe) according to this embodiment, and the second column stores the time step (=Δt0) to be incremented during calculation, as shown in Table 20. The increment value (Δt0) obtained by multiplying the number of calculations by the time becomes the specified time T, which is the time at which the time history response analysis is performed (see FIG. 42). The third column stores the output frequency, i.e., how often the calculation results are output. For example, if you specify 10,000 here, a video snapshot will be recorded in the output file, the trajectory file (out.trj) described below, once every 10,000 calculations, and once every 1 / 10 of that, or 1,000 times, load and deformation information for analysis will be recorded as time history data in the output file, the calculation results file (dataout.csv) described below.

[0105] [Table 20]

[0106] [Main flow of calculation] Next, the main calculation flow of the calculation program (calc.exe) will be explained using FIG. When the calculation starts, first, necessary information is read from the aforementioned input files (analysis model file (test.mod), parameter file (parm.csv), external force condition file (load.csv), calculation condition file (default.ini)) (step S1), and initial values ​​of the analysis model are set (step S2). Then, time t is set to t = 0 (step S3).

[0107] Next, the process proceeds to step S4, where it is determined whether the time t is less than the specified time T. If the time t is less than the specified time T, in step S5, the minimum value (i=1 in the illustrated embodiment) is assigned to the spring number i (parameter ID), and the external force at time t is input to the analysis model according to the mode and calculation conditions specified in the external force condition file, and calculation begins (step S6).

[0108] Next, the process proceeds to step S7, where it is determined whether the spring number i is less than the maximum value imax of the parameter ID. If the spring number i is less than the maximum value imax, the process proceeds to the stress vector calculation process for the spring i (step S8).

[0109] (Stress vector calculation process) Now, referring to Figure 43, the stress vector calculation process for spring i will be described. The stress vector for spring i is calculated. Specifically, the stress vector calculation process for spring i first proceeds to step S9, where it is determined whether the spring with spring number i is a post-assembled spring. Specifically, for the spring with i in the first column of the parameter file mentioned above, it is determined whether the value in the second column of the same line is 1. If it is 1, it proceeds to step S10, and if not, it proceeds to step S11.

[0110] In step S10, the element stiffness matrix [Ki]t shown in the above-mentioned equation 4 of spring i, which is an axle assembly spring, is determined from the parameter information recorded in the third column and thereafter of the same line in the parameter file, and the stress vector [Fi]t acting on spring i is calculated based on the above-mentioned equations 4 and 5. When the spring type is a frame spring, the element stiffness matrix [Ki] is given by the following formula 8.

[0111]

number

[0112] If spring i is not a post assembly spring and the process proceeds to step S11, it is similarly determined whether spring i is a joint spring or not by checking whether the value in the second column of the parameter file is 2 or not.If it is 2, the process proceeds to step S12; if not, the process proceeds to step S13.

[0113] In step S12, the element stiffness matrix [Ki]t of spring i, which is a joint spring (compression / tension elastic-plastic spring), is determined from the parameter information recorded in the third column and thereafter of the same line in the parameter file, and the stress vector [Fi]t acting on spring i is calculated based on the above-mentioned equations 4 and 5. When the spring type is a joint spring, the element stiffness matrix [Ki] is given by the following formula 9.

[0114]

number

[0115] If spring i is not a joint spring and the process proceeds to step S13, it is similarly determined whether spring i is a rotational spring based on whether the value in the second column of the parameter file is 3, and if it is 3, the process proceeds to step S14, otherwise it proceeds to step S15. In step S14, the element stiffness matrix [Ki]t of spring i, which is a rotational spring, is determined from the parameter information recorded in the third column and beyond of the same line in the parameter file, and the stress vector [Fi]t acting on spring i is calculated based on the above-mentioned equations 4 and 5. When the type of spring is a rotational spring, the element stiffness matrix [Ki] is expressed by the following formula 10.

[0116]

number

[0117] If spring i is not a rotational spring and the process proceeds to step S15, the process similarly determines whether spring i is a structural spring or not by checking whether the value in the second column of the parameter file is 4. If it is 4, the process proceeds to step S16; if not, the process proceeds to step S17.

[0118] In step S16, the element stiffness matrix [Ki]t of spring i, which is a structural spring, is determined from the parameter information recorded in the third column and thereafter of the same line in the parameter file, and the stress vector [Fi]t acting on spring i is calculated based on the above-mentioned equations 4 and 5. When the type of spring is a structural spring, the element stiffness matrix [Ki] is expressed by the following formula 11.

[0119]

number

[0120] If spring i is not a structural spring and the process proceeds to step S17, the process similarly determines whether spring i is a compression brace spring or not by checking whether the value in the second column of the parameter file is 6 or not. If it is 6, the process proceeds to step S18; if not, the process proceeds to step S19.

[0121] In step S18, the element stiffness matrix [Ki]t of the compression brace spring i is determined from the parameter information recorded in the third column and thereafter of the parameter file, and the stress vector [Fi]t acting on the spring i is calculated based on the above-mentioned equations 4 and 5. If the spring is a compression brace spring, the element stiffness matrix [Ki] will be calculated using the same formula as for the structural spring. However, the spring i, which is a compression brace spring, is assumed not to be subjected to a tensile force when calculating the stress vector [Fi]t.

[0122] If spring i is not a compression brace spring and the process proceeds to step S19, the process similarly determines whether spring i is a tension brace spring by checking whether the value in the second column of the parameter file is 5. If it is 5, the process proceeds to step S20; if not, the process proceeds to step S21.

[0123] In step S20, the element stiffness matrix [Ki]t of spring i, which is a tension brace spring, is determined, and based on the above-mentioned equations 4 and 5, the stress vector [Fi]t acting on spring i is calculated, assuming that spring i does not act in the compression direction.

[0124] If spring i is not a tension brace spring and the process proceeds to step S21, the process similarly determines whether spring i is a foundation beam spring by checking whether the value in the second column of the parameter file is 7. If it is 7, the process proceeds to step S22; if not, the process proceeds to step S23.

[0125] In step S22, the element stiffness matrix [Ki]t of the spring i, which is the foundation beam spring, is determined, and the stress vector [Fi]t acting on the spring i is calculated based on the above-mentioned equations 4 and 5.

[0126] If spring i is not a foundation beam spring and the process proceeds to step S23, the process similarly determines whether spring i is an anchor spring by checking whether the value in the second column of the parameter file is 8. If it is 8, the process proceeds to step S24; if not, the process proceeds to step S25.

[0127] In step S24, the element stiffness matrix [Ki]t of the spring i, which is the anchor spring, is determined, and the stress vector [Fi]t acting on the spring i is calculated based on the above-mentioned equations 4 and 5.

[0128] If spring i is not an anchor spring and the process proceeds to step S25, spring i automatically becomes a ground spring, so the element stiffness matrix [Ki]t of spring i, which is a ground spring, is determined, and the stress vector [Fi]t is calculated based on the above-mentioned equations 4 and 5.

[0129] Returning to FIG. 41, when the stress vector calculation process for spring i is completed in step S8, the process proceeds to step S26, the spring number i is incremented by 1, and the process returns to step S7 to calculate the stress vector for the next spring i+1.

[0130] Then, when the stress vectors have been calculated for all springs, it is determined in step S7 that the spring number i has reached the maximum value imax of the parameter ID, and the process proceeds to step S27.

[0131] In step S27, the minimum value of the node number (1 in the illustrated example) is substituted for node number A, and the process proceeds to step S28.

[0132] Proceeding to step S28, it is determined whether node number A is less than the maximum value Amax. If node number A has not reached the maximum value Amax, proceed to step S29, and calculation of the stress vector for node A begins.

[0133] In step S29, as shown in the above-mentioned equation 6, the stress vectors acting on all the springs connected to a certain node A are added together to calculate the stress vector [FA]t acting on the node A. The node numbers are numbers that are automatically assigned by the interface program described above based on the information in the analysis data file.

[0134] Then, as shown in the above-mentioned equation 7, the calculated stress vector of node A is numerically integrated using Newmark's β method (average acceleration method β=1 / 4) to calculate the acceleration [aA]t, velocity [vA]t, and displacement increment [ΔDA]t at time t (steps S30 to S32). After calculating these calculated values, node number A is incremented by one in step S33, and the process returns to step S28, where the calculation of each of the calculated values, such as the stress vector of the next node A+1, is repeated until node number A reaches the maximum value Amax.

[0135] As described above, when the calculations for all nodes are completed, step S28 determines that the node number A has reached the maximum value Amax, and the process proceeds to step S34, where the time t is incremented by the time increment Δt0 specified in the second column of the calculation condition file, and the process returns to step S4, where it is determined whether the next time t + Δt0 is less than the specified time T, and if the specified time T has not been reached, the external force at the next time t + Δt0 is input into the analysis model and the above-mentioned calculation is repeated.

[0136] Then, if the time t reaches the specified time T in step S4, the process proceeds to step S35. In step S35, the [foundation reaction force], "horizontal force on each floor," "absolute ground displacement," and "absolute displacement at a specific point on each floor" are calculated by predetermined calculations from the above-mentioned calculated values, and the calculation results are output and saved as time history data in the output file, a trajectory file (out.trj) and a calculation result file (dataout.csv) described below, and the calculation ends. This specified time T is determined by the number of calculations entered in the calculation condition file mentioned above multiplied by the time increment (Δt0).

[0137] Output File Next, the output file will be described. As described above, the calculation program according to this embodiment outputs calculation results, etc. to three files (see Table 2): a trajectory file (out.trj), a calculation result file (detaout.csv), and an analysis continuation file (cont.mod) (see Figure 14, Table 2).

[0138] (Trajectory file) The trajectory file (out.trj) is a file in which the time history data of the coordinates of each element (component or joint) of the analysis model is output from the calculation program of this embodiment and saved, and is a file for viewing using the aforementioned interface program.

[0139] (Calculation result file) The calculation results file (detaout.csv) is a CSV file in which the values ​​are arranged in the order of [base reaction force], "horizontal force on each floor," "absolute ground displacement," and "absolute displacement on each floor," and the period is the reciprocal of the [number of calculations x time increment (Δt0)] specified in the calculation conditions file (default.ini) mentioned above. This "absolute displacement on each floor" is a time history record of the absolute displacement of the four corners of each floor of the analysis model. The base shear force at the first floor (base shear force) is calculated as the base reaction force, the floor shear force at a given floor i is calculated as the sum of the horizontal forces at floors i and above, and the relative displacement at floor i is calculated as (absolute displacement at floor i + 1) - (absolute displacement at floor i).

[0140] (Analysis continuation file) The analysis continuation file (cont.mod) is a file that corresponds to the analysis model file in the input file and contains information about the elements and springs of the analysis model after calculation.If this file is input as an input file into a computer using the calculation program of this embodiment and recalculated, continuous collapse simulation will be possible.

[0141] As described above, the calculation program (calc.exe) according to the embodiment includes the steps of: calculating the stress acting on each spring using the element stiffness matrix corresponding to the type of spring in the analysis model using the distinct element method based on information stored in an input file, which combines multiple nodes and multiple types of springs to model a wooden building, its foundation, and the ground, and the assumptions for time history response analysis during an earthquake; and summing the stresses acting on all springs connected to each node. Therefore, it is possible to accurately calculate and simulate the behavior of a wooden building, its foundation, and the ground during an earthquake, from a state of advanced deformation to collapse, which could not be accurately simulated using conventional simulation programs such as the finite element method, so as to match the behavior of the actual building during an earthquake.

[0142] Furthermore, according to the calculation program (calc.exe) of the embodiment, the analytical model of the foundation and ground is modeled by combining multiple nodes and multiple types of springs, including the foundation beams, the anchor bolts connecting the foundation beams to the wooden building, and the foundation reaction force acting on the foundation beams from the ground. Therefore, rather than relying on conventional structural calculations based on the allowable stress design of wooden frame construction houses, the behavior of the foundation and ground can be accurately calculated and simulated using the distinct element method to match the behavior of the actual building during an earthquake, thereby verifying the safety of the foundation. As a result, the foundation of a wooden building can be optimized.

[0143] Furthermore, the calculation program (calc.exe) according to the embodiment models a wooden building constructed using the post-and-beam construction method by dividing it into elastic-plastic springs of the post, elastic-plastic springs of the joints, elastic-plastic rotational springs of the joints, truss springs of the vertical and horizontal structural planes, compression brace springs, tension brace springs, elastic springs of the foundation beams, elastic springs of the anchor bolts connecting the foundation beams to the wooden building, and elastic springs of the foundation based on the foundation reaction force acting from the ground to the foundation beams. Parameter information corresponding to each type of spring is input in advance, and this parameter information is used to determine the element stiffness matrix and calculate the stress vector acting on the springs. This makes it possible to accurately calculate and simulate the behavior of a wooden building constructed using the post-and-beam construction method from a state where deformation has progressed to collapse, so as to match the behavior of an actual building during an earthquake. Therefore, time history response analysis of a wooden building during an earthquake up to its collapse can be performed with high accuracy so as to match the actual behavior during an earthquake. [Explanation of symbols]

[0144] 22 Foundation beam spring (elastic spring of foundation beam) 24 Anchor spring (elastic spring for anchor bolt) 32 Ground spring (elastic spring of the foundation based on the foundation reaction force acting from the ground to the foundation beam)

Claims

1. A wooden building collapse simulation program for causing a computer to execute a time history response analysis of a wooden building during an earthquake up to its collapse, The method comprises the steps of: calculating the stress acting on each spring using the element stiffness matrix according to the type of spring in the analysis model by using the distinct element method based on the information of an analysis model that models the wooden building, its foundation, and the ground by combining multiple nodes and multiple types of springs, which are saved in an input file, and the preconditions for the time history response analysis during an earthquake; and adding up the stress acting on all springs connected to each node. A simulation program for the collapse of wooden buildings.

2. The analytical model of the foundation and the ground is characterized in that the foundation beam, the anchor bolts connecting the foundation beam and the wooden building, and the foundation reaction force acting on the foundation beam from the ground are modeled by a combination of multiple nodes and multiple types of springs. The wooden building collapse simulation program according to claim 1.

3. The spring types of the analysis model are modeled as elastoplastic springs of the framework, elastoplastic springs of the joints, elastoplastic rotational springs of the joints, truss springs of the vertical and horizontal structural planes, compression brace springs, tension brace springs, elastic springs of the foundation beams, elastic springs of the anchor bolts connecting the foundation beams to the wooden building, and elastic springs of the foundation based on the foundation reaction force acting from the ground to the foundation beams, and the input file contains parameter information according to the modeled spring types, and the method is characterized in that the computer is caused to execute a step of determining the element stiffness matrix using this parameter information.

3. A wooden building collapse simulation program according to claim 1 or 2.

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