Design method for foundation structures, calculation program, foundation structure, and seismic diagnosis method for existing foundation structures

Abstract

Based on a simple method, it is possible to design the foundation structure with rational specifications that take into account energy absorption. [Solution] A method for designing a foundation structure for supporting civil engineering structures and building structures, wherein the foundation structure is designed to satisfy equation (1) while considering the energy absorption of the foundation structure. The method comprises the steps of setting the external forces acting on the foundation structure, setting the specifications of the foundation structure, setting an analysis model that takes the ground into consideration using the specifications and external forces, performing a static pushover analysis using the analysis model, and determining whether equation (1) is satisfied. [Mathematics 1] TIFF2026168597000019.tif22170

Description

[Technical Field]

[0001] The present invention relates to a method for designing foundation structures, a calculation program, a foundation structure, and a method for seismic diagnosis of existing foundation structures. [Background technology]

[0002] In designing foundation structures that support civil engineering structures and building structures, static design methods are often employed, which replace the dynamic response of the structure to external forces such as earthquakes with a static design. In such static design methods, the load-bearing capacity of the foundation structure is designed to be greater than or equal to the external forces acting on the foundation structure. For example, Non-Patent Literature 1 lists the inertial force acting on the above-ground portion of the superstructure, the inertial force acting on the underground portion of the superstructure, the earth pressure during an earthquake, and the load due to the horizontal displacement of the ground as external forces in the design of foundation structures against earthquakes. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Design Guidelines for Building Foundation Structures," pp. 95-106, "Section 4.4 Seismic Loads," 2019, Architectural Institute of Japan [Overview of the project] [Problems that the invention aims to solve]

[0004] During an earthquake, the foundation structure absorbs energy, reducing the external forces acting on it. However, conventional static design methods for foundation structures, as described above, do not take into account this reduction in external forces due to energy absorption by the foundation structure. As a result, foundation structures can sometimes be designed with excessive specifications, leading to a lack of economic rationality.

[0005] Furthermore, when designing foundation structures using dynamic design methods that employ dynamic analysis such as time history response analysis, the reduction of external forces due to energy absorption by the foundation structure is automatically considered by making appropriate settings. However, determining specifications using time history response analysis from the initial stages of structural design requires significant computational costs and manpower, making it difficult to widely adopt.

[0006] This invention has been made in view of the above-mentioned problems, and aims to provide a design method for a foundation structure, a calculation program, a foundation structure, and a seismic diagnosis method for an existing foundation structure that can be designed with a rational specification that takes into account the energy absorption of the foundation structure, based on a simple method. [Means for solving the problem]

[0007] (1) Embodiment 1 of the foundation structure design method according to the present invention is a foundation structure design method for designing a foundation structure that supports civil engineering structures and building structures, characterized in that the energy absorption of the foundation structure is taken into consideration and the design satisfies formula (1).

[0008]

number

[0009] According to the foundation structure design method of the present invention, the design can take into account that the external forces acting on the foundation structure are reduced by the energy absorption of the foundation structure. By using this simple method and considering the reduction of external forces through energy absorption by the foundation structure, it is possible to design the foundation structure with rational specifications without compromising its safety.

[0010] (2) Aspect 2 of the present invention is a method for designing a foundation structure according to aspect 1, wherein the foundation structure may be a pile foundation.

[0011] In this case, because the foundation structure is a pile foundation, energy absorption can be expected through plastic deformation in the pile body, pile head joint, or foundation beam, thereby efficiently suppressing external forces acting on the foundation structure.

[0012] (3) Aspect 3 of the present invention may be characterized in that, in the method for designing a foundation structure of Aspect 1 or Aspect 2, the foundation structure includes steel material.

[0013] In this case, by including steel in the foundation structure, stable energy absorption by the steel can be expected, and external forces acting on the foundation structure can be efficiently suppressed.

[0014] (4) Aspect 4 of the present invention may be characterized in that, in a method for designing a foundation structure in any one of aspects 1 to 3, energy absorption due to plastic deformation of the foundation structure is taken into consideration.

[0015] In this case, by considering the reduction of external forces due to energy absorption associated with the plastic deformation of the foundation structure, a more rational design can be achieved.

[0016] (5) Aspect 5 of the present invention is a method for designing a foundation structure in any one of aspects 1 to 4, wherein the foundation structure is composed of structural members and the ground, and it is preferable to calculate the energy absorption share between the structural members and the ground.

[0017] In this case, when the foundation structure is subjected to external forces, both the structural members constituting the foundation structure and the ground can resist and absorb energy. By calculating the energy absorption share between the structural members and the ground constituting the foundation structure, the proportion of energy absorption by the structural members in the total energy absorption can be determined. Therefore, it is possible to reflect in the design an external force reduction that considers only the energy absorption by structural members, whose material is clearer and which can reliably absorb energy compared to the ground, allowing for the design of a foundation structure with a large safety margin and excellent cost-effectiveness. Furthermore, in cases where uncertainties such as variations in ground physical properties are small and the reliability of ground physical properties is high, it is possible to reflect in the design the external force reduction that takes into account part or the entirety of the energy absorption by the ground, in addition to the energy absorption by the structural members.

[0018] (6) Aspect 6 of the present invention is the foundation structure design method according to any one of Aspect 1 to Aspect 5, which may be characterized by comprising the steps of: setting an external force acting on the foundation structure; setting specifications of the foundation structure; using the specifications and the external force to set an analysis model that considers the ground; performing a static pushover analysis using the analysis model; and determining that the following formula (1) is satisfied.

[0019] In this case, the design can be carried out with rational specifications that take into account the reduction of external force due to the energy absorption of the foundation structure.

[0020] (7) Aspect 7 of the present invention is the foundation structure design method according to any one of Aspect 1 to Aspect 5, which may be characterized by comprising the steps of: setting an external force acting on the foundation structure; setting specifications of the foundation structure; using the specifications and the external force to set an analysis model that considers the ground; performing a static pushover analysis using the analysis model; determining that the following formula (1) is satisfied; and performing a time history response analysis reflecting the specifications of the foundation structure for which it has been determined that the formula (1) is satisfied, to confirm that at least one of the sectional force and deformation occurring in the foundation structure is equal to or less than an allowable value.

[0021] In this case, in addition to being able to design with rational specifications that take into account the reduction of external force due to the energy absorption of the foundation structure, it is possible to verify that the specifications of the foundation structure determined in consideration of the external force reduction by the energy absorption of the foundation structure have no safety issues.

[0022] (8) Embodiment 8 of the calculation program according to the present invention is a calculation program that performs the design method of the foundation structure of Embodiment 6 on a computer, characterized by performing the steps of setting external forces acting on the foundation structure, setting specifications of the foundation structure, setting an analysis model that takes the ground into consideration using the specifications and the external forces, performing a static pushover analysis using the analysis model, and determining that the formula (1) is satisfied.

[0023] According to the calculation program of the present invention, it is possible to design with reasonable specifications that take into account the reduction of external forces due to energy absorption by the foundation structure.

[0024] (9) Embodiment 9 of the calculation program according to the present invention is a calculation program that performs the design method of the foundation structure of Embodiment 7 on a computer, characterized by performing the steps of: setting external forces acting on the foundation structure; setting specifications of the foundation structure; setting an analysis model that takes the ground into consideration using the specifications and the external forces; performing a static pushover analysis using the analysis model; determining that the formula (1) is satisfied; and performing a time history response analysis that reflects the specifications of the foundation structure which has been determined to satisfy the formula (1), to confirm that at least one of the sectional forces and deformations occurring in the foundation structure is below an allowable value.

[0025] According to the calculation program of the present invention, in addition to being able to design with reasonable specifications that take into account the reduction of external forces due to energy absorption by the foundation structure, it is also possible to verify that the specifications of the foundation structure determined considering the reduction of external forces due to energy absorption by the foundation structure are not problematic in terms of safety.

[0026] (10) Embodiment 10 of the foundation structure according to the present invention is characterized in that it supports civil engineering structures and building structures, and the energy absorption of the foundation structure is taken into consideration and satisfies formula (1).

[0027]

number

[0028] According to the foundation structure of the present invention, the external force acting on the foundation structure is reduced by the energy absorption of the foundation structure. In such a foundation structure, by considering the reduction of external forces due to the energy absorption of the foundation structure based on a simple method, it is possible to design the foundation structure with reasonable specifications without compromising its safety.

[0029] (11) Embodiment 11 of the seismic diagnosis method for existing foundation structures according to the present invention is characterized by considering the energy absorption of existing foundation structures that support civil engineering structures and building structures, and determining whether the equation (1)' is satisfied.

[0030]

number

[0031] According to the seismic diagnosis method for existing foundation structures of the present invention, a rational seismic diagnosis can be performed on existing foundation structures, taking into account the reduction of external forces due to energy absorption by the existing foundation structure.

[0032] (12) Aspect 12 of the present invention may be characterized in that, in the seismic diagnosis method for an existing foundation structure of aspect 11, the steps are: setting external forces acting on the existing foundation structure; setting specifications for the existing foundation structure; setting an analysis model that takes the ground into consideration using the specifications and the external forces; performing a static pushover analysis using the analysis model; and determining that the formula (1)' is satisfied based on the analysis results of the static pushover analysis.

[0033] In this case, a rational seismic diagnosis can be performed on the existing foundation structure, taking into account the reduction of external forces due to energy absorption by the existing foundation structure.

[0034] (13) Aspect 13 of the present invention may be characterized in that, in the seismic diagnosis method for an existing foundation structure of aspect 11, the steps are: setting external forces acting on the existing foundation structure; setting specifications of the existing foundation structure; setting an analysis model that takes the ground into consideration using the specifications and the external forces; performing a static pushover analysis using the analysis model; determining that the formula (1)' is satisfied based on the analysis results of the static pushover analysis; and performing a time history response analysis that reflects the specifications of the existing foundation structure which has been determined to satisfy the formula (1)', to confirm that at least one of the sectional forces and deformations occurring in the existing foundation structure is below an allowable value.

[0035] According to the seismic diagnosis method for existing foundation structures of the present invention, in addition to being able to perform a rational seismic diagnosis of an existing foundation structure that takes into account the reduction of external forces due to energy absorption by the existing foundation structure, it is possible to verify that the existing foundation structure is not unsafe by performing a seismic diagnosis that takes into account the reduction of external forces due to energy absorption by the existing foundation structure.

[0036] (14) Embodiment 14 of the calculation program according to the present invention is a calculation program that performs the seismic diagnosis method for an existing foundation structure of Embodiment 12 on a computer, characterized in that it performs the steps of setting external forces acting on the existing foundation structure, setting specifications of the existing foundation structure, setting an analysis model that takes the ground into consideration using the specifications and the external forces, performing a static pushover analysis using the analysis model, and determining that the formula (1)' is satisfied.

[0037] According to the calculation program of the present invention, a rational seismic diagnosis can be performed that takes into account the reduction of external forces due to energy absorption by the existing foundation structure.

[0038] (15) Embodiment 15 of the calculation program according to the present invention is a calculation program that performs the seismic diagnosis method for an existing foundation structure of Embodiment 13 on a computer, characterized in that it performs the steps of: setting the external forces acting on the existing foundation structure; setting the specifications of the existing foundation structure; setting an analysis model that takes the ground into consideration using the specifications and the external forces; performing a static pushover analysis using the analysis model; determining that the formula (1)' is satisfied; and performing a time history response analysis that reflects the specifications of the existing foundation structure which has been determined to satisfy the formula (1)', to confirm that at least one of the sectional forces and deformations occurring in the existing foundation structure is below an allowable value.

[0039] According to the calculation program of the present invention, in addition to being able to perform a rational seismic diagnosis of an existing foundation structure that takes into account the reduction of external forces due to energy absorption by the existing foundation structure, it is possible to verify that the existing foundation structure is not unsafe by performing a seismic diagnosis that takes into account the reduction of external forces due to energy absorption by the existing foundation structure.

[0040] (16) Aspect 16 of the present invention is a method for designing a foundation structure in any one of aspects 1 to 7, characterized in that the foundation structure includes reinforcement of an existing foundation structure and is designed to satisfy formula (1)'', taking into consideration the energy absorption of the existing foundation structure, the energy absorption of the foundation structure including the reinforcement of the existing foundation structure, or the energy absorption of the reinforcement of the existing foundation structure.

[0041]

number

[0042] According to the foundation structure design method including reinforcement of existing foundation structures of the present invention, the design can take into account that the external forces acting on the foundation structure including reinforcement of existing foundation structures are reduced by energy absorption of the foundation structure, energy absorption of the foundation structure including reinforcement of existing foundation structures, or energy absorption of reinforcement of existing foundation structures. By using this simple method and considering the reduction of external forces through energy absorption by the foundation structure, including reinforcement of the existing foundation structure, it is possible to design the foundation structure with rational specifications without compromising its safety.

[0043] (17) Aspect 17 of the present invention is a method for designing a foundation structure as described in Aspect 16, characterized in that a computer program for executing the method for designing a foundation structure including reinforcement of an existing foundation structure includes the steps of: setting external forces acting on the foundation structure including reinforcement of an existing foundation structure; setting specifications for the foundation structure including reinforcement of an existing foundation structure; setting an analysis model that takes the ground into consideration using the specifications and the external forces; performing a static pushover analysis using the analysis model; and determining that the formula (1)'' is satisfied.

[0044] According to the calculation program of the present invention, the foundation structure can be designed with rational specifications that take into account the reduction of external forces through energy absorption by the foundation structure, including reinforcement of the existing foundation structure.

[0045] (18) Embodiment 18 of the present invention is a method for designing a foundation structure as described in Embodiment 16, characterized in that a computer program for executing the method for designing a foundation structure including reinforcement of an existing foundation structure includes the steps of: setting external forces acting on the foundation structure including reinforcement of an existing foundation structure; setting specifications for the foundation structure including reinforcement of an existing foundation structure; setting an analysis model that takes the ground into consideration using the specifications and the external forces; performing a static pushover analysis using the analysis model; determining that the formula (1)'' is satisfied; and performing a time history response analysis that reflects the specifications of the foundation structure including reinforcement of an existing foundation structure, which has been determined to satisfy the formula (1)'', to confirm that at least one of the sectional forces and deformations occurring in the foundation structure including reinforcement of an existing foundation structure is below an allowable value.

[0046] According to the calculation program of the present invention, the foundation structure can be designed with rational specifications that take into account the reduction of external forces through energy absorption by the foundation structure, including reinforcement of the existing foundation structure.

[0047] (19) Embodiment 19 of the foundation structure according to the present invention is characterized in that the energy absorption of the existing foundation structure, the energy absorption of the foundation structure including reinforcement of the existing foundation structure, or the energy absorption of reinforcement of the existing foundation structure are taken into consideration and the equation (1)'' is satisfied.

[0048]

number

[0049] According to the foundation structure of the present invention, the external forces acting on the foundation structure are reduced by energy absorption of the existing foundation structure, energy absorption of the foundation structure including reinforcement of the existing foundation structure, or energy absorption of reinforcement of the existing foundation structure. In such a foundation structure, by considering the reduction of external forces due to energy absorption of the foundation structure including reinforcement of the existing foundation structure based on a simple method, it is possible to design the foundation structure with reasonable specifications without compromising its safety. [Effects of the Invention]

[0050] According to the present invention's design method for foundation structures, calculation program, foundation structure, and seismic diagnosis method for existing foundation structures, it is possible to design a foundation structure with rational specifications that take into account energy absorption, based on a simple method. [Brief explanation of the drawing]

[0051] [Figure 1] This figure shows the design flow according to the first design method according to an embodiment of the present invention. [Figure 2] This figure shows a diagram illustrating a design method for a foundation structure according to an embodiment, and is an example of an analytical model that takes the ground conditions into consideration. [Figure 3] This figure shows the relationship between elastic response and elastoplastic response based on the constant energy law. [Figure 4] This diagram shows the external forces acting on a foundation structure, taking into account the energy absorption of the foundation structure, when the reduction of external forces due to energy absorption by the piles is expected. [Figure 5] This diagram shows the external forces acting on a foundation structure, taking into account the energy absorption of the foundation structure, when external forces are expected to be reduced by energy absorption by the piles and the ground. [Figure 6] This diagram shows the design flow according to the second design method. [Modes for carrying out the invention]

[0052] The following describes, with reference to the drawings, a design method for a foundation structure, a calculation program, a foundation structure, and a seismic diagnosis method for an existing foundation structure according to embodiments of the present invention.

[0053] (First Embodiment) The foundation structure design method according to this embodiment is a method for designing a foundation structure 1 that supports civil engineering structures and building structures, and the design takes into account the energy absorption of the foundation structure 1 and satisfies equation (1) (see Figure 1).

[0054]

number

[0055] The superstructure supported by the foundation structure may be a civil engineering structure, a building structure, or any other type of structure. Examples of civil engineering structures include road bridges, railway bridges, port facilities, airport facilities, and dams. Examples of building structures include government buildings, hospitals, schools, apartment buildings, skyscrapers, data centers, factories, warehouses, and detached houses. Examples of other structures include gas holders, power transmission towers, and various types of equipment.

[0056] Figure 2 is a diagram illustrating a design method for foundation structures, and shows an example of an analytical model that takes the ground conditions into consideration. As shown in Figure 2, the foundation structure 1 consists of structural members 11 (shown as piles in Figure 2) and the ground 12. The structural members 11 may be a single member or composed of multiple members. The ground 12 may be sandy soil or cohesive soil, and may or may not liquefy during an earthquake.

[0057] The material of the structural members 11 that make up the foundation structure 1 can be steel, concrete, wood, or any other material, and there are no particular restrictions.

[0058] Foundation structure 1 may be any of the following: direct foundation (isolated foundation, strip foundation, raft foundation, etc.), pile foundation, sheet pile foundation, steel pipe pile foundation, diaphragm wall foundation, caisson foundation, pile draft foundation, or a foundation using multiple foundation types in combination.

[0059] It is desirable that at least a portion of the structural member 11 is embedded in the ground 12. In this case, it is not necessary for the entire structural member 11 to be embedded in the ground 12, and there may be a portion of the structural member 11 that protrudes from the ground 12.

[0060] Foundation structure 1 may or may not be connected to a superstructure not shown. If foundation structure 1 is a pile foundation, the degree of fixation of the pile head may be a fixed pile head condition with complete rotational restraint, a free pile head condition with no rotational restraint, or a semi-rigid pile head condition with partial rotational restraint.

[0061] When the foundation structure 1 is a pile foundation, the pile type for the structural member 11 may be any of the following: steel pipe piles, CFT piles (concrete-filled steel pipe piles), precast concrete piles (PHC piles, PRC piles, PC piles, SC piles, SPHC piles, SPRC piles, SSC piles, WSC piles, etc.), RC piles, cast-in-place concrete piles, steel pipe-wrapped cast-in-place concrete piles, wooden piles, H-beam piles, etc., or multiple pile types may be used in combination. The support type for the foundation piles may be either support piles or friction piles. In a pile foundation, the location where energy is absorbed by plastic deformation may be the pile body, the pile head joint, or the foundation beam.

[0062] Next, the specific design method for the foundation structure 1 according to this embodiment will be explained based on the following two design methods.

[0063] <First design method> Figure 1 shows the design flow according to the first design method. The first design method, as shown in Figure 1, includes the steps of setting the external forces acting on the foundation structure 1, setting the specifications of the foundation structure 1, setting an analysis model as shown in Figure 2 that takes the ground into consideration using the specifications and external forces, performing a static pushover analysis using the analysis model, and determining whether equation (1) is satisfied.

[0064] The first design method can be performed by manual calculation, but it can be more rationally implemented by using a computer program that performs some or all of the calculations. Specifically, as shown in Figure 2, the computer program for the first design method performs the following steps: step S1 to set the external force P acting on the foundation structure; step S2 to set the specifications of the foundation structure 1; step S3 to set an analysis model that takes the ground into consideration using the specifications and the external force; step S4 to perform a static pushover analysis using the analysis model; and step S5 to determine that equation (1) is satisfied.

[0065] A computer (CPU or MPU) not shown, which stores and executes the calculation program according to the first design method described above, has a setting unit, an analysis execution unit, and a determination unit. The setting unit executes steps S1 to S3 of the calculation program. The analysis execution unit executes step S4 of the calculation program. The determination unit executes step S5 of the calculation program.

[0066] The analysis model can be any of the following: a beam-spring frame model, a FEM (Finite Element Method) model, a DEM (Discrete Element Method) model, or an MPM (Material Point Method) model. The analysis model shall take the ground conditions into consideration. It may include only the foundation structure, or it may also include the superstructure and other surrounding environments. Furthermore, it may be a 3D or 2D model. In addition, boundary conditions on the analysis model may be set as appropriate.

[0067] Static pushover analysis can be performed using either load increments or displacement increments, and the load increments and displacement increments may be varied and combined depending on the type of external force.

[0068] Here, we will specifically explain the external force P, yield strength Q, and external force reduction coefficient α in the above formula (1). The external force P acting on the foundation structure 1 refers to at least one of the forces acting on the foundation structure 1, such as the constant axial force due to the self-weight of the superstructure, the fluctuating axial force due to the superstructure, seismic loads (superstructure inertial force, foundation inertial force), wind loads, snow loads, mechanical loads, ground reaction forces, and ground displacement. If the foundation structure 1 is a pile foundation, during an earthquake, vertical forces (constant axial force, fluctuating axial force), horizontal forces (superstructure inertial force, foundation inertial force), ground displacement, etc., act on the foundation structure 1 as external forces P. Here, superstructure inertial force refers to, for example, the required horizontal bearing capacity of the superstructure or the superstructure's own horizontal bearing capacity.

[0069] The load-bearing capacity Q of the foundation structure 1 may be the load-bearing capacity that the structural members constituting the foundation structure 1 can exert within the elastic deformation range, or it may be the load-bearing capacity that can be exerted within the allowable limits for sectional forces and deformation through plastic deformation. The allowable limits for sectional forces and deformation of the foundation structure 1 are determined according to the assumed external forces and the performance required for the entire structure, including the superstructure.

[0070] The external force reduction coefficient α due to energy absorption by the foundation structure 1, as shown in equation (1) above, satisfies 0 < α < 1. This indicates that the closer the value of α is to 0, the greater the energy absorption of the foundation structure 1 and the greater the reduction of the external force P acting on the foundation structure 1.

[0071] Energy absorption may be due to any of the following: plastic strain energy, elastic strain energy, frictional energy, dissipated energy, thermal energy, vibrational energy, hysteretic energy, various types of damping energy, or other forms of energy. When the foundation structure 1 undergoes plastic deformation, energy absorption occurs due to plastic strain energy, and the external force P acting on the foundation structure 1 is efficiently reduced.

[0072] <Setting external forces> In step S1 shown in Figure 1 of this design example, for example, the superstructure is assumed to be a five-story reinforced concrete building, and the foundation structure 1 supporting it is designed to withstand a Level 2 load (major earthquake). The foundation structure 1 is subjected to vertical force F1 (normal axial force, fluctuating axial force), horizontal force F2 (superstructure inertial force, foundation inertial force), and ground displacement F3.

[0073] <Setting the specifications for the foundation structure> Next, in step S2, the specifications of foundation structure 1 are set. Foundation structure 1 is a pile foundation. Steel pipe piles 11 are used for the pile foundation, for example, with a pile diameter D of 1000 mm, a plate thickness t of 19 mm, and a material standard of SKK490. The steel pipe piles 11 consist of one pile per column and are assumed to have been constructed using the enlarged foundation reinforcement method for excavated piles. The ground 12 is assumed to be a sandy soil-dominant ground as the site on which the building structure will be erected.

[0074] <Setting up an analysis model that takes ground conditions into consideration> Next, in step S3, a pile frame model as shown in Figure 2 is set up. The steel pipe piles 11 are modeled as beam elements (fiber models) 11A, and the ground 12 is modeled as spring elements 12A. The pile heads 11a of the steel pipe piles 11 are rigidly connected to the foundation beam 14. The lower ends 11b of the steel pipe piles 11 are horizontal pin rollers 15. Further details will be determined by referring to standards and papers such as "Guidelines for the Design of Building Foundation Structures" (Architectural Institute of Japan, 2019) and "Strength and Deformation Performance of Foundation Members" (Architectural Institute of Japan, 2022).

[0075] <Perform static pushover analysis> Next, in step S4, a static pushover analysis is performed in which the constant axial force is kept constant, and the fluctuating axial force F1, horizontal force F2 (superstructure inertial force, foundation inertial force), and ground displacement F3 are gradually increased. The applied force is in the direction of arrow F1 in Figure 2, and the fluctuating axial force F1, horizontal force F2 (superstructure inertial force, foundation inertial force), and ground displacement F3 are gradually increased to a magnitude exceeding the Level 2 load as needed.

[0076] In a static pushover analysis, if the constant axial force is kept constant while the fluctuating axial force F1, horizontal force F2 (superstructure inertial force, foundation inertial force), and ground displacement F3 are gradually increased, the allowable deformation value for foundation structure 1 is reached at a certain analysis step. The allowable deformation value for foundation structure 1 is defined as the amount of deformation at which either of the following events occurs: (a) critical strain occurs at one point on one pile, or (b) plastic hinges occur at two points on one pile. Here, critical strain ε u For example, in the case of steel pipe piles, ε u It is given by =0.44t / D (where t is the plate thickness and D is the pile diameter). Furthermore, the allowable deformation value for the foundation structure 1 may be set to a rotation angle of 7 / 1000, etc., and it is preferable to determine it according to the performance required for the entire structure including the superstructure.

[0077] <Evaluation of formula (1)> Next, in step S5, it is determined whether equation (1) is satisfied. If it is determined that equation (1) is satisfied (S5: Yes), the design flow ends. If it is determined that equation (1) is not satisfied (S5: No), the process returns to the external force setting step in step S1 and the flow from step S1 to step S5 is repeated for reconsideration.

[0078] The external force P acting on the foundation structure 1 is, for example, a horizontal force equivalent to a Level 2 load (major earthquake) (the sum of the superstructure inertial force and the foundation inertial force). The load-bearing capacity Q of foundation structure 1 is defined, for example, as the horizontal force (sum of superstructure inertial force and foundation inertial force) when the allowable deformation of the foundation structure is reached in a static pushover analysis. The external force reduction coefficient α due to energy absorption by the foundation structure 1 is determined by the following method. By summing the energy amounts of the piles 11 and the ground 12 from the results of the static pushover analysis until the bearing capacity Q of the foundation structure 1 is generated, that is, until the allowable deformation value for the foundation structure 1 is reached, the energy sharing ratio of the piles 11 and the ground 12 can be determined. For example, the energy absorption of the piles 11 may be calculated as 60%, and the energy absorption of the ground 12 as 40%.

[0079] Figure 3 shows the relationship between the elastic response and the elastoplastic response based on the constant energy law. For foundation structure 1, we assume Newmark's constant energy law holds between elastic energy and elastoplastic energy, as shown in Figure 3. A foundation structure exhibiting an elastic response like the OA line (the line connecting points OA) and a foundation structure exhibiting an elastoplastic response like the OCD line (the line connecting points OCD) are evaluated as having equivalent seismic resistance if the area M1 of △OAB (the triangular region enclosed by points OAB) and the area M2 of □OCDE (the quadrilateral region enclosed by points OCDE) are equal. In Figure 3, the elastoplastic response is described as a perfectly elastoplastic type as shown by the OCD line, but the path of the OCD line may be nonlinear, and there may be a gradient between C and D; it is sufficient that the area M1 of △OAB for the elastic response and the area M2 of □OCDE for the elastoplastic response are equivalent. Here, L shown in Figure 3 is the horizontal force, and the coefficient K is evaluated by equations (2) and (3) based on the constant energy law.

[0080]

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[0081] Figure 4 shows the external forces acting on the foundation structure 1, taking into account the energy absorption of the foundation structure 1, in the case where energy absorption by the pile 11 is expected. The foundation structure 1 resists the external force P with both the structural member (steel pipe pile 11 in this embodiment) and the ground 12. In the case of a pile foundation, for example, the structural member pile 11 and the ground 12 resist the force. When considering only the energy absorption by the pile 11, which is a structural member whose material is clearly defined compared to the ground 12 and which can reliably absorb energy, the reduction of the external force due to the energy absorption of the pile 11 is reflected by multiplying the horizontal force L borne by the pile by a coefficient K, as shown in Figure 4. The external force acting on the foundation structure 1, considering the energy absorption of the foundation structure 1, is expressed as α × P, as shown in equation (4). The coefficient α is K × pile burden ratio (%) + ground burden ratio (%).

[0082]

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[0083] Figure 5 shows the external force acting on the foundation structure 1 in consideration of the energy absorption of the foundation structure 1, in the case where energy absorption by the pile 11 and the ground 12 is expected. When uncertainties such as variations in ground physical properties are small and the reliability of ground physical properties is high, when not only energy absorption by the pile 11 which is a structural member but also energy absorption by the ground 12 are considered, as shown in Fig. 5, in addition to multiplying the horizontal force F2 borne by the pile by a coefficient K, the horizontal force borne by the ground is multiplied by a coefficient K', so that the external force reduction due to energy absorption by both the pile 11 and the ground 12 is reflected. The external force acting on the foundation structure 1 in consideration of the energy absorption of the foundation structure 1 is expressed as α×P as in Equation (5). The coefficient K' may be set to the same value as the coefficient K, or may be a different value. The coefficient α is K × pile bearing ratio (%) + K' × ground bearing ratio (%).

[0084]

Equation

[0085] The external force reduction coefficient α due to energy absorption of the foundation structure may be evaluated by a formula based on the specifications of the pile 11 and the ground 12. For example, evaluation may be performed using index (1) that incorporates the standardized diameter-thickness ratio (Equation (6)), which is a parameter representing the characteristics of the steel pipe pile 11, and the pile characteristic value β with an overbar (a parameter that takes ground characteristics into account, Equation (7)) by exponentiation operation.

[0086] Here, D is the pile diameter (mm), t is the plate thickness (mm), σ y is the yield point of the pile (N / mm 2 ), E p is the Young's modulus of the pile (N / mm 2 ), β with an overbar is the dimensionless pile characteristic value (dimensionless in units of m), k h is the horizontal ground reaction coefficient (N / mm 3 ), I p is the secondary moment of area of the pile section (mm 4), where a is a constant and b is a constant. However, different unit systems are acceptable as long as the units are consistent across the constituent indicators.

[0087]

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[0088]

number

[0089] The horizontal ground reaction coefficient k that constitutes β (upper bar) h In calculating this, publicly known methods can be used. For example, the Architectural Institute of Japan's "Guidelines for the Design of Building Foundation Structures" (Architectural Institute of Japan: Guidelines for the Design of Building Foundation Structures, pp. 178-283, 2019), the Japan Road Association's "Specifications for Road Bridges and Commentary IV: Substructures" (Japan Road Association: Specifications for Road Bridges and Commentary IV: Substructures, pp. 226-316, 2017), the Railway Technical Research Institute's "Design Standards for Railway Structures and Others: Foundation Structures" (Railway Technical Research Institute: Design Standards for Railway Structures and Others: Foundation Structures, pp. 247-330, 2012), the Japan Port and Harbor Association's "Technical Standards for Port Facilities and Others (Volume 2)" (Japan Port and Harbor Association: Technical Standards for Port Facilities and Others (Volume 2), pp. 675-744, 2018), and Francis's formula (Francis, AJ: Analysis of Examples include "Pile Groups with Flexural Resistance," Journal of the Soil Mechanics and Foundations Division, ASCE, Vol.90, Issue 3, pp.10-32, 1964; the Kishida-Nakai method (Hideaki Kishida, Shoichi Nakai: Horizontal Resistance of Piles Considering Soil Failure, Transactions of the Architectural Institute of Japan, No. 281, pp.41-55, 1979.7); and methods presented by various organizations (Ministry of Land, Infrastructure, Transport and Tourism, Japan Society of Civil Engineers, Japanese Geotechnical Society, etc.).

[0090] <Second design method> Figure 6 shows the design flow according to the second design method. The second design method, as shown in Figure 6, includes the steps of: setting the external forces acting on the foundation structure 1; setting the specifications of the foundation structure 1; setting an analysis model that takes the ground into consideration using the specifications and external forces; performing a static pushover analysis using the analysis model; determining whether equation (1) is satisfied; performing a time history response analysis that reflects the specifications of the foundation structure 1 which has been determined to satisfy equation (1); and confirming that at least one of the sectional forces and deformations occurring in the foundation structure 1 is below an allowable value. In other words, the second design method is a design flow that includes confirmation by time history response analysis in the first design method described above.

[0091] In the second design method, the allowable values ​​for sectional forces and deformations of the foundation structure during a major earthquake can be considered in accordance with the performance required for the entire structure, including the superstructure. Furthermore, even when allowing the maximum allowable sectional forces and deformations of the foundation structure, it is desirable to limit them to levels that do not compromise the axial force-holding performance that supports the self-weight of the superstructure, from the perspective of protecting human lives and ensuring continued functionality. As a guideline for the amount of deformation that does not cause loss of axial force holding performance as a pile itself, for example, in the case of steel pipe piles, it is desirable to keep the deformation below the critical strain (usually around a few percent strain) if the reduction in load-bearing capacity occurs due to local buckling, and below the fracture strain (usually around 10-30% strain) if the reduction in load-bearing capacity occurs due to fracture. In the case of precast concrete piles or cast-in-place concrete piles, it is desirable to keep the deformation below the crushing strain (usually around 0.2-0.4% strain) if crushing occurs. However, these are merely guidelines for the amount of deformation that does not cause loss of axial force holding performance as a pile itself, and it is preferable to determine the allowable values ​​of deformation as a foundation structure (displacement, rotation angle, location and number of plastic hinges, etc.) according to the performance required for the entire structure including the superstructure.

[0092] In the second design method, the analysis models for static pushover analysis and time history response analysis may be the same or different. Furthermore, the type of external force P and the seismic motion used in the time history response analysis can be considered as appropriate.

[0093] The second design method can be performed by manual calculation, but it can be more rationally implemented by using a computer calculation program that performs some or all of the calculations on a computer, and up to step S5, the same calculation program as the first design method described above is executed. That is, as shown in Figure 6, the calculation program for the second design method performs the following steps: step S1 to set the external force P acting on the foundation structure; step S2 to set the specifications of the foundation structure 1; step S3 to set an analysis model that takes the ground into consideration using the specifications and external force; step S4 to perform a static pushover analysis using the analysis model; step S5 to determine that equation (1) is satisfied; step S6 to perform a time history response analysis that reflects the specifications of the foundation structure 1 which has been determined to satisfy equation (1); and step S7 to confirm that at least one of the sectional forces and deformations occurring in the foundation structure 1 is below the allowable value. In the second design method, if step S5 determines that equation (1) is satisfied (S5:Yes), time history response analysis is performed in step S6. If the determination does not satisfy equation (1) (step S5:No), the process returns to the external force setting step in step S1, and the flow from step S1 to step S5 is repeated.

[0094] A computer (CPU or MPU) not shown, which stores and executes the calculation program according to the second design method described above, has a setting unit, an analysis execution unit, and a determination unit. The setting unit executes steps S1 to S3 of the calculation program. The analysis execution unit executes steps S4 and S6 of the calculation program. The determination unit executes steps S5 and S7 of the calculation program.

[0095] <Performing time history response analysis> In step S5, after confirming that equation (1) is satisfied, in step S6, a time history response analysis is performed to verify that the specifications of the foundation structure, which were determined considering the reduction of external forces due to energy absorption by the foundation structure, are safe. The analysis model will be based on the pile and ground specifications determined in the flow described so far. The seismic waves to be input can be appropriately selected from publicly announced waves, observed waves, site waves, and ground-level surge waves.

[0096] <Determination of whether at least one of the sectional force or deformation is below the allowable value> Next, in step S7, it is determined whether at least one of the sectional forces and deformations occurring in the foundation structure 1 is below the allowable value based on the time history response analysis in step S6. The allowable values ​​for the sectional forces and deformations of the foundation structure 1 when subjected to a major earthquake can be considered according to the performance required for the entire structure, including the superstructure. However, even when allowing the maximum allowable sectional forces and deformations of the foundation structure 1, it is desirable to limit them to levels that do not result in the loss of axial force holding performance that supports the self-weight of the superstructure, from the viewpoint of protecting human lives and ensuring continued functionality. In step S7, if at least one of the sectional forces and deformations occurring in the foundation structure 1 is below the allowable value (step S7: Yes), the design flow is completed. If it is not confirmed that the values ​​are below the allowable value (step S7: No), the process returns to the external force setting step in step S1 and the flow from step S1 to step S7 is repeated for reconsideration.

[0097] In the first and second design methods described above, various literatures can be referenced when considering the external force P acting on the foundation structure 1, the bearing capacity Q possessed by the foundation structure 1, the allowable values ​​of the sectional forces and deformations of the foundation structure 1, the analytical model, static pushover analysis, time history response analysis, etc. For example, you may refer to standards such as "Guidelines for the Design of Building Foundation Structures" (Architectural Institute of Japan: Guidelines for the Design of Building Foundation Structures, 2019), "Specifications for Road Bridges and Commentary IV: Substructures" (Japan Road Association: Specifications for Road Bridges and Commentary, 2017), "Design Standards for Railway Structures and Commentary: Foundation Structures" (Railway Technical Research Institute: Design Standards for Railway Structures and Commentary, 2012), and "Technical Standards for Port Facilities and Commentary" (Japan Port and Harbor Association: Technical Standards for Port Facilities and Commentary, 2018), as well as other papers.

[0098] The specifications of foundation structure 1, the analysis model, the conditions for static pushover analysis, the conditions for time history response analysis, the external force P acting on foundation structure 1, the load-bearing capacity Q of foundation structure 1, the allowable values ​​for section forces and deformation of foundation structure 1, and the value of the external force reduction coefficient α may be reviewed as appropriate during the design process. Furthermore, the order of the design flow considerations is not limited to the order shown in Figures 1 and 6; it may be rearranged slightly depending on the situation, and the considerations may be repeated. The design flow includes only the minimum number of considerations, and other considerations not included in the flow may be added as appropriate.

[0099] According to the foundation structure design method described above, the foundation structure is designed to support civil engineering structures and building structures, taking into account the energy absorption of the foundation structure and designing it to satisfy the above formula (1).

[0100] In this embodiment, the design can take into account that the external forces acting on the foundation structure are reduced by the energy absorption of the foundation structure. Based on this simple method, it is possible to design a rational specification without compromising the safety of the foundation structure, by considering the reduction of external forces through energy absorption by the foundation structure.

[0101] Furthermore, in this embodiment, the foundation structure 1 may be a pile foundation. In this case, because the foundation structure is a pile foundation, energy absorption can be expected through plastic deformation in the pile body, pile head joint, or foundation beam, thereby efficiently suppressing external forces acting on the foundation structure.

[0102] Furthermore, in this embodiment, the foundation structure includes steel. In this case, by including steel in the foundation structure, stable energy absorption by the steel can be expected, and external forces acting on the foundation structure can be efficiently suppressed.

[0103] Furthermore, in this embodiment, energy absorption due to plastic deformation of the foundation structure is taken into consideration. By considering the reduction of external forces due to energy absorption associated with the plastic deformation of the foundation structure, a more rational design specification can be achieved.

[0104] Furthermore, in the foundation structure design method according to this embodiment, the foundation structure is composed of structural members and the ground, and the division of energy absorption between the structural members and the ground is calculated. With this configuration, when the foundation structure is subjected to external forces, both the structural members constituting the foundation structure and the ground resist and absorb energy. By calculating the energy absorption share between the structural members and the ground, the proportion of energy absorption by the structural members in the total energy absorption can be determined. Therefore, it is possible to reflect in the design an external force reduction that considers only the energy absorption by structural members, whose material is clearer and which can reliably absorb energy compared to the ground, allowing for the design of a foundation structure with a large safety margin and excellent cost-effectiveness. Furthermore, when uncertainties such as variations in ground properties are small and the reliability of ground properties is high, it is possible to incorporate into the design external force reduction that considers not only energy absorption by structural members but also some or all of the energy absorption by the ground.

[0105] Furthermore, the foundation structure design method according to this embodiment includes the steps of setting the external forces acting on the foundation structure, setting the specifications of the foundation structure, setting an analysis model that takes the ground into consideration using the specifications and external forces, performing a static pushover analysis using the analysis model, and determining whether equation (1) is satisfied. This configuration allows for a rational design that takes into account the reduction of external forces through energy absorption by the foundation structure.

[0106] Furthermore, the foundation structure design method according to this embodiment includes the steps of: setting the external forces acting on the foundation structure; setting the specifications of the foundation structure; setting an analysis model that takes the ground into consideration using the specifications and external forces; performing a static pushover analysis using the analysis model; determining whether equation (1) is satisfied; and performing a time history response analysis that reflects the specifications of the foundation structure which has been determined to satisfy equation (1), to confirm that at least one of the sectional forces and deformations occurring in the foundation structure is below an allowable value. This configuration allows for a rational design that takes into account the reduction of external forces through energy absorption by the foundation structure, and also enables verification that the specifications of the foundation structure determined with consideration for the reduction of external forces through energy absorption by the foundation structure are safe.

[0107] Furthermore, in the calculation program according to this embodiment, the design method for the foundation structure is executed by computer. The calculation program performs the following steps: setting the external forces acting on the foundation structure; setting the specifications of the foundation structure; setting an analysis model that takes the ground into consideration using the specifications and external forces; performing a static pushover analysis using the analysis model; and determining whether equation (1) is satisfied. This configuration allows for a rational design that takes into account the reduction of external forces through energy absorption by the foundation structure.

[0108] Furthermore, in the calculation program according to this embodiment, the design method for the foundation structure is executed by computer. The calculation program performs the following steps: setting the external forces acting on the foundation structure; setting the specifications of the foundation structure; setting an analysis model that takes the ground into consideration using the specifications and external forces; performing a static pushover analysis using the analysis model; determining whether equation (1) is satisfied; and performing a time history response analysis that reflects the specifications of the foundation structure which has been determined to satisfy equation (1), to confirm that at least one of the sectional forces and deformations occurring in the foundation structure is below the allowable value. This configuration allows for a rational design that takes into account the reduction of external forces through energy absorption by the foundation structure, and also enables verification that the specifications of the foundation structure determined with consideration for the reduction of external forces through energy absorption by the foundation structure are safe.

[0109] (Second Embodiment) The seismic diagnosis method for existing foundation structures according to the second embodiment includes the steps of: setting the external forces acting on the existing foundation structure that supports civil engineering structures and building structures; setting the specifications of the existing foundation structure; setting an analysis model that takes the ground into consideration using the specifications and external forces; performing a static pushover analysis using the analysis model; and determining whether the energy absorption of the existing foundation structure is satisfied by considering the analysis results of the static pushover analysis. Since these specific methods are the same as those of the first embodiment described above, they are omitted in the second embodiment.

[0110]

number

[0111] In this case, a computer program can be used to perform seismic diagnosis on the existing foundation structure. Specifically, the calculation program performs the following steps: setting the external forces acting on the existing foundation structure; setting the specifications of the existing foundation structure; setting an analysis model that takes the ground into consideration using the specifications and external forces; performing a static pushover analysis using the analysis model; and determining whether equation (1)' is satisfied.

[0112] According to the seismic diagnosis method and calculation program for existing foundation structures of the second embodiment, a rational seismic diagnosis can be performed on existing foundation structures, taking into account the reduction of external forces due to energy absorption by the existing foundation structure.

[0113] Furthermore, in the second embodiment, the process may include a step of performing a time history response analysis that reflects the specifications of the existing foundation structure which has been determined to satisfy equation (1)' in the determination step described above, in order to confirm that at least one of the sectional forces and deformations occurring in the existing foundation structure is below an allowable value. In this case, the calculation program performs the steps of setting the external forces acting on the existing foundation structure, setting the parameters of the existing foundation structure, setting an analysis model that takes the ground into consideration using the parameters and external forces, performing a static pushover analysis using the analysis model, determining that equation (1)' is satisfied, and performing a time history response analysis that reflects the specifications of the existing foundation structure which has been determined to satisfy equation (1)', in order to confirm that at least one of the sectional forces and deformations occurring in the existing foundation structure is below an allowable value.

[0114] In this case, a rational seismic diagnosis can be performed that takes into account the reduction of external forces due to energy absorption by the existing foundation structure. Furthermore, the seismic diagnosis that takes into account the reduction of external forces due to energy absorption by the existing foundation structure can verify that the existing foundation structure is not unsafe.

[0115] (Third embodiment) The foundation structure according to the third embodiment satisfies equation (1)'' by taking into account the energy absorption of the existing foundation structure, the energy absorption of the foundation structure including the reinforcement of the existing foundation structure, or the energy absorption of the reinforcement of the existing foundation structure.

[0116]

number

[0117] In this case, the foundation structure includes reinforcement of the existing foundation structure. The design method for the foundation structure in this case takes into account the energy absorption of the existing foundation structure, the energy absorption of the foundation structure including the reinforcement of the existing foundation structure, or the energy absorption of the reinforcement of the existing foundation structure, and is designed to satisfy the above formula (1)''.

[0118] Furthermore, the design method according to the third embodiment includes the steps of: setting the external forces acting on the foundation structure, including the reinforcement of the existing foundation structure that supports the civil engineering structure or building structure; setting the specifications of the foundation structure, including the reinforcement of the existing foundation structure; setting an analysis model that takes the ground into consideration using the specifications and the external forces; performing a static pushover analysis using the analysis model; and determining that the energy absorption of the foundation structure, including the reinforcement of the existing foundation structure, satisfies equation (1)''.

[0119] In this case, a computer program can be used to perform a calculation on a computer to design the foundation structure, including the reinforcement of the existing foundation structure. Specifically, the calculation program performs the following steps: setting the external forces acting on the foundation structure, including the reinforcement of the existing foundation structure; setting the specifications of the foundation structure, including the reinforcement of the existing foundation structure; setting an analysis model that takes the ground into consideration using the specifications and the external forces; performing a static pushover analysis using the analysis model; and determining that the formula (1)'' is satisfied.

[0120] In this case, the design can take into account the reduction of external forces acting on the foundation structure through energy absorption by the existing foundation structure, energy absorption by the foundation structure including reinforcement of the existing foundation structure, or energy absorption by reinforcement of the existing foundation structure. By considering the reduction of external forces through energy absorption by the foundation structure based on this simple method, it is possible to design the foundation structure with rational specifications without compromising its safety.

[0121] Furthermore, in the third embodiment, the process may include a step of performing a time history response analysis that reflects the specifications of the foundation structure, including the reinforcement of the existing foundation structure, which has been determined to satisfy equation (1)'' in the determination step described above, to confirm that at least one of the sectional forces and deformations occurring in the foundation structure, including the reinforcement of the existing foundation structure, is below an allowable value. In this case, the calculation program performs the steps of setting the external forces acting on the foundation structure, including the reinforcement of the existing foundation structure; setting the parameters of the foundation structure, including the reinforcement of the existing foundation structure; setting an analysis model that takes the ground into consideration using the parameters and external forces; performing a static pushover analysis using the analysis model; determining that equation (1)'' is satisfied; and performing a time history response analysis that reflects the specifications of the foundation structure, including the reinforcement of the existing foundation structure, which has been determined to satisfy equation (1)'', to confirm that at least one of the sectional forces and deformations occurring in the foundation structure, including the reinforcement of the existing foundation structure, is below an allowable value.

[0122] In this case, it is possible to design the foundation structure with reasonable specifications that take into account the reduction of external forces due to energy absorption by the foundation structure, including reinforcement of the existing foundation structure. Furthermore, it is possible to verify that the specifications of the foundation structure determined by considering the energy absorption of the existing foundation structure, the energy absorption of the foundation structure including reinforcement of the existing foundation structure, or the reduction of external forces due to energy absorption of reinforcement of the existing foundation structure are not problematic in terms of safety.

[0123] The embodiments of the design method for foundation structures, calculation program, foundation structure, and seismic diagnosis method for existing foundation structures according to the present invention have been described above. However, the present invention is not limited to the embodiments described above and can be modified as appropriate without departing from the spirit of the invention. Furthermore, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, without departing from the spirit of the present invention.

[0124] Furthermore, in the above case, the calculation program itself will implement the functions of this embodiment. As the transmission medium for the calculation program, a communication medium (such as a priority line like optical fiber or a wireless line) in a computer network system (such as a LAN, WAN such as the Internet, or a wireless communication network) that propagates and supplies program information as a carrier wave can be used.

[0125] Furthermore, means for supplying the above-mentioned arithmetic program to a computer, such as a storage medium storing such arithmetic program, can also be configured. As such a storage medium, various recording media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, magnetic tapes, non-volatile memory cards, and ROMs can be used. [Explanation of Symbols]

[0126] 1 Basic structure 11. Structural members, piles, steel pipe piles 12 Ground

Claims

1. A method for designing foundation structures for supporting civil engineering structures and building structures, A method for designing a foundation structure that takes into account the energy absorption of the aforementioned foundation structure and satisfies equation (1). [Math 1]

2. The design method for a foundation structure according to claim 1, wherein the foundation structure is a pile foundation.

3. The method for designing a foundation structure according to claim 1, wherein the foundation structure includes steel.

4. A method for designing a foundation structure according to claim 1, which takes into account energy absorption due to plastic deformation of the foundation structure.

5. The aforementioned foundation structure consists of structural members and the ground. A method for designing a foundation structure according to claim 1, comprising calculating the energy absorption sharing between the structural member and the ground.

6. A step of setting the external forces acting on the aforementioned foundation structure, The process of setting the specifications of the aforementioned foundation structure, A step of setting up an analysis model that takes the ground into consideration using the above parameters and the above external forces, The process involves performing a static pushover analysis using the aforementioned analysis model, A step of determining whether the above formula (1) is satisfied, A method for designing a foundation structure according to any one of claims 1 to 5, comprising:

7. A step of setting the external forces acting on the aforementioned foundation structure, The process of setting the specifications of the aforementioned foundation structure, A step of setting up an analysis model that takes the ground into consideration using the above parameters and the above external forces, The process involves performing a static pushover analysis using the aforementioned analysis model, A step of determining whether the above formula (1) is satisfied, A step of performing a time history response analysis that reflects the specifications of the foundation structure which has been determined to satisfy the above formula (1), and confirming that at least one of the sectional forces and deformations occurring in the foundation structure is below an allowable value, A method for designing a foundation structure according to any one of claims 1 to 5, comprising:

8. A computer program for executing the design method of the foundation structure described in claim 6, The steps include setting the external forces acting on the aforementioned foundation structure, The steps include setting the specifications of the aforementioned foundation structure, The steps include setting up an analysis model that takes the ground conditions into account using the aforementioned parameters and the aforementioned external forces, The steps include: performing a static pushover analysis using the aforementioned analysis model; The steps include determining whether the above formula (1) is satisfied, A calculation program that performs the following operations.

9. A computer program for executing the design method of the foundation structure described in claim 7, The steps include setting the external forces acting on the aforementioned foundation structure, The steps include setting the specifications of the aforementioned foundation structure, The steps include setting up an analysis model that takes the ground conditions into account using the aforementioned parameters and the aforementioned external forces, The steps include: performing a static pushover analysis using the aforementioned analysis model; The steps include determining whether the above formula (1) is satisfied, A step of performing a time history response analysis that reflects the specifications of the foundation structure which has been determined to satisfy the above formula (1), and confirming that at least one of the sectional forces and deformations occurring in the foundation structure is below an allowable value, A calculation program that performs the following operations.

10. A foundation structure that supports civil engineering structures and building structures, and whose energy absorption is taken into consideration, satisfying equation (1). [Math 2]

11. A seismic diagnosis method for existing foundation structures that support civil engineering structures and building structures, which considers the energy absorption of the existing foundation structure and determines whether it satisfies formula (1)'. [Math 3]

12. A step of setting the external forces acting on the existing foundation structure, The process of setting the specifications of the aforementioned existing foundation structure, A step of setting up an analysis model that takes the ground into consideration using the above parameters and the above external forces, The process involves performing a static pushover analysis using the aforementioned analysis model, A step of determining whether the formula (1)' is satisfied based on the analysis results of the static pushover analysis, A seismic diagnosis method for an existing foundation structure according to claim 11, comprising:

13. A step of setting the external forces acting on the existing foundation structure, The process of setting the specifications of the aforementioned existing foundation structure, A step of setting up an analysis model that takes the ground into consideration using the above parameters and the above external forces, The process involves performing a static pushover analysis using the aforementioned analysis model, A step of determining whether the formula (1)' is satisfied based on the analysis results of the static pushover analysis, A step of performing a time history response analysis that reflects the specifications of the existing foundation structure which has been determined to satisfy the above formula (1)', and confirming that at least one of the sectional forces and deformations occurring in the existing foundation structure is below the allowable value, A seismic diagnosis method for an existing foundation structure according to claim 11, comprising:

14. A computer program for performing the seismic diagnosis method for an existing foundation structure as described in claim 12, The steps include setting the external forces acting on the existing foundation structure, The steps include setting the specifications of the existing foundation structure, The steps include setting up an analysis model that takes the ground conditions into account using the aforementioned parameters and the aforementioned external forces, The steps include: performing a static pushover analysis using the aforementioned analysis model; The step of determining whether the above formula (1)' is satisfied, A calculation program that performs the following operations.

15. A computer program for performing the seismic diagnosis method for an existing foundation structure as described in claim 13, The steps include setting the external forces acting on the existing foundation structure, The steps include setting the specifications of the existing foundation structure, The steps include setting up an analysis model that takes the ground conditions into account using the aforementioned parameters and the aforementioned external forces, The steps include: performing a static pushover analysis using the aforementioned analysis model; The step of determining whether the above formula (1)' is satisfied, The steps include: performing a time history response analysis that reflects the specifications of the existing foundation structure, which has been determined to satisfy the above formula (1)', to confirm that at least one of the sectional forces and deformations occurring in the existing foundation structure is below an allowable value; A calculation program that performs the following operations.

16. The aforementioned foundation structure includes reinforcement of the existing foundation structure. A method for designing a foundation structure according to any one of claims 1 to 5, which involves designing the foundation structure to satisfy formula (1)'', taking into consideration the energy absorption of the existing foundation structure, the energy absorption of the foundation structure including reinforcement of the existing foundation structure, or the energy absorption of reinforcement of the existing foundation structure. [Math 4]

17. A calculation program that performs the design method for a foundation structure, including the reinforcement of an existing foundation structure, on a computer, in the method for designing a foundation structure according to claim 16, The steps include setting the external forces acting on the foundation structure, including reinforcement of the existing foundation structure, The steps include setting the specifications of the foundation structure, including reinforcement of the existing foundation structure, The steps include setting up an analysis model that takes the ground conditions into account using the aforementioned parameters and the aforementioned external forces, The steps include: performing a static pushover analysis using the aforementioned analysis model; The steps include determining whether the above formula (1)'' is satisfied, A calculation program that performs the following operations.

18. A calculation program that performs the design method for a foundation structure, including the reinforcement of an existing foundation structure, on a computer, in the method for designing a foundation structure according to claim 16, The steps include setting the external forces acting on the foundation structure, including reinforcement of the existing foundation structure, The steps include setting the specifications of the foundation structure, including reinforcement of the existing foundation structure, The steps include setting up an analysis model that takes the ground conditions into account using the aforementioned parameters and the aforementioned external forces, The steps include: performing a static pushover analysis using the aforementioned analysis model; The steps include determining whether the above formula (1)'' is satisfied, The steps include: performing a time history response analysis that reflects the specifications of the foundation structure, including the reinforcement of the existing foundation structure, which has been determined to satisfy the above formula (1)'', and confirming that at least one of the sectional forces and deformations occurring in the foundation structure, including the reinforcement of the existing foundation structure, is below an allowable value; A calculation program that performs the following operations.

19. A foundation structure that satisfies formula (1)'' by considering the energy absorption of the existing foundation structure, the energy absorption of the foundation structure including reinforcement of the existing foundation structure, or the energy absorption of reinforcement of the existing foundation structure. [Math 5]

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