Design system, design method, and design program for seismic isolation structure

Abstract

To design a base isolation structure that controls the response of a building to an appropriate range regardless of the level of a giant earthquake.SOLUTION: In a design system 1 of a base isolation structure, a first damping characteristic of a first damper is such that a damping coefficient is gradually or stepwise reduced as a response amount increases, and a second damping characteristic of a second damper is such that a damping force is rapidly increased at a switching amount which is a predetermined response amount as a response amount increases, a control part 2 determines the number of first dampers so that a performance index of a building is satisfied when a level 3 earthquake ground motion is inputted to an analysis model of the building in which the first dampers are set; and some of the first dampers are replaced with second dampers so that the performance index of the building is satisfied when a level 2 earthquake ground motion is inputted to the analysis model of the building in which the first dampers are set, the number of the first dampers and the second dampers is determined so that the displacement of a base isolation layer becomes a target value or less.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a design system, a design method, and a design program for a seismic isolation structure. [Background technology]

[0002] Base-isolated buildings require measures to withstand massive earthquakes, including long-period ground motion. Base-isolated buildings often use seismic isolation bearings, such as laminated rubber bearings, and dampers to attenuate the building's shaking as seismic isolation components (see, for example, Patent Document 1). Base-isolated buildings designed to withstand Level 2 earthquake motion, the strongest level, in accordance with the existing Building Standards Act, may experience large response displacements in the event of an earthquake of Level 2 or higher (hereinafter referred to as Level 3 earthquake motion), potentially exceeding the design clearance of the base-isolated layer. In particular, buildings on narrow urban sites and buildings using a base-isolation retrofit construction method, in which base-isolation devices are applied to existing buildings, are more likely to collide with retaining walls in the event of Level 3 earthquake motion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-248520 Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, when a base-isolated building is designed for a level 3 earthquake, the response acceleration of the superstructure located above the base isolation layer during a level 2 earthquake will be greater than before. This necessitates a larger cross-section of the components in the superstructure. As such, there is a trade-off between the response displacement and response acceleration of the superstructure during a massive earthquake, including level 2 and level 3 earthquakes. For this reason, there is a demand for a design system for base-isolated structures that can achieve an appropriate response by appropriately arranging dampers to suppress the response displacement during a level 3 earthquake while also reducing the response acceleration during the smaller level 2 earthquake. [Means for solving the problem]

[0005] The present disclosure provides a design system for a seismic isolation structure. The design system for the seismic isolation structure comprises a damping characteristic memory unit that stores the damping characteristics of dampers to be placed in the seismic isolation layer of the building, and a control unit that performs response analysis, wherein the damping characteristic memory unit stores information regarding the first damping characteristic of a first damper and information regarding the second damping characteristic of a second damper, wherein the first damping characteristic gradually or stepwise decreases the damping coefficient as the response amount increases, and the second damping characteristic suddenly increases the damping force at a switching amount that is a predetermined response amount as the response amount increases, and the control unit determines the number of the first dampers so that a performance index of the building is satisfied when a level 3 earthquake motion is input to the analysis model of the building in which the first dampers are set, replaces some of the first dampers with the second dampers so that the performance index of the building is satisfied when a level 2 earthquake motion is input to the analysis model of the building in which the first dampers are set, and determines the numbers of the first dampers and the second dampers so that the seismic isolation layer displacement is equal to or less than a target value when a level 3 earthquake motion is input to the analysis model in which the first dampers have been replaced with the second dampers. [Effects of the Invention]

[0006] According to the present invention, it is possible to design a seismic isolation structure that controls the response of a building within an appropriate range, regardless of the magnitude of a huge earthquake. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a building equipped with a seismic isolation structure. [Figure 2] 4 is a diagram showing the damping characteristics of the variable damping coefficient damper of the embodiment. FIG. [Figure 3] 4 is a table showing damping characteristics of the variable damping coefficient damper of the embodiment. [Figure 4] 10 is a table showing the damping characteristics of each damper of the embodiment. [Figure 5] FIG. 2 is a diagram illustrating a hardware configuration of the information processing apparatus according to the embodiment. [Figure 6] FIG. 2 is a block diagram of a design system according to the embodiment. [Figure 7] 10 is a flowchart showing a setting procedure for response analysis according to the embodiment. [Figure 8] 10 is a flowchart showing a procedure for response analysis according to the embodiment. [Figure 9] 10 is a flowchart showing a procedure for response analysis according to the embodiment. [Figure 10] 10 is a flowchart showing a procedure for response analysis according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of a system, a method and a program for designing a seismic isolation structure will be described below with reference to FIGS. Figure 1 shows an example of a building 100 that is the target of a design system for a seismic isolation structure, and schematically illustrates a cross section of its seismic isolation layer 101. The seismic isolation layer 101 is provided with seismic isolation bearings (not shown), such as laminated rubber bearings, elastic sliding bearings, or rolling bearings, directly below columns 102. The seismic isolation layer 101 also has multiple types of dampers 10, which are seismic isolation members, in the X and Y directions.

[0009] The dampers 10 are connected to a structure composed of columns 102, beams 103, etc. Here, each damper 10 is a viscous damping type damper. For example, the dampers 10 are velocity-dependent bilinear dampers, velocity-dependent amplification dampers, and variable damping coefficient dampers. For ease of explanation, hereinafter, velocity-dependent bilinear dampers will be simply referred to as "oil dampers," and velocity-dependent amplification dampers will be referred to as "rotational amplification dampers." The oil dampers and rotational amplification dampers correspond to the first velocity-dependent dampers. The variable damping coefficient dampers correspond to the second velocity-dependent dampers.

[0010] Each damper 10 has different damping characteristics. The damping characteristics of the oil damper and the rotation amplification damper are the first damping characteristics. The first damping characteristics decrease the damping coefficient in stages or gradually as the response speed increases. The response speed corresponds to the response amount.

[0011] The oil damper may obtain bilinear damping characteristics by opening and closing an adjustment valve or relief valve provided on the piston, while the rotation amplification damper may obtain damping characteristics by converting axial motion into the motion of a rotating body that rotates while receiving viscous resistance.

[0012] The damping characteristic of the variable damping coefficient damper is a second damping characteristic, which exhibits a low damping force at speeds less than a predetermined response speed, and a high damping force at speeds greater than or equal to the predetermined response speed.

[0013] The response speed varies depending on the level of earthquake motion. Level 2 earthquake motion is the strongest earthquake motion that can occur at the location of building 100 from the present to the future. Level 3 earthquake motion is an extremely large earthquake motion that is even greater than Level 2 earthquake motion.

[0014] The range of response speeds indicating low damping characteristics overlaps with the range of response speeds during level 2 earthquake motion. The range of response speeds indicating high damping characteristics overlaps with the range of response speeds during level 3 earthquake motion. The predetermined response speed indicating the boundary between low damping characteristics and high damping characteristics may be approximately the boundary between the response speed during level 2 earthquake motion and the response speed during level 3 earthquake motion. Alternatively, the predetermined response speed indicating the boundary between low damping characteristics and high damping characteristics may be included in the response speed range in which the response speed changes from level 2 earthquake motion to level 3 earthquake motion.

[0015] In time history response analysis, when the type of earthquake motion input to the analysis model or the elapsed time since input changes, the response speed during Level 2 earthquake motion and the response speed during Level 3 earthquake motion change within the response speed range. The response speed range is determined by simulation or experiment. When the response speed is almost at the boundary, it means that the response speed is close to the boundary to the extent that switching to high damping characteristics based on the response speed suppresses the response displacement during Level 3 earthquake motion.

[0016] The damping characteristics of variable damping coefficient dampers are such that their damping force is smaller than that of oil dampers and rotational amplification dampers in the response speed range when earthquake motion equivalent to level 2 is input. The damping characteristics of variable damping coefficient dampers show a rapid increase in damping force at a specified response speed as the response speed increases, increasing the damping coefficient.

[0017] The damping characteristics of a variable damping coefficient damper may increase the damping force suddenly at a predetermined response speed as the response speed increases, and then maintain the damping coefficient before the increase, or may decrease the damping coefficient from the damping coefficient before the increase when a predetermined relief load is reached. The sudden increase in damping force is a transient state in which the damping characteristics change from low to high. The sudden increase in damping force means that the damping force increases to such an extent that the damping coefficient is greater than the damping coefficient of the low damping characteristics and the damping coefficient of the high damping characteristics.

[0018] A variable damping coefficient damper may switch between high and low damping characteristics by opening and closing an adjustment valve or relief valve provided on the piston, or by switching flow paths in response to pressure changes within the damper. In addition to the function of switching between high and low damping characteristics depending on speed, a variable damping coefficient damper may also have a function of changing damping force depending on displacement, such as switching flow paths in response to piston displacement.

[0019] <Damper damping characteristics> (Variable damping coefficient damper) Next, the damping characteristics of each damper 10 will be described in detail.

[0020] Figure 2 shows an example of the damping characteristic C1 versus response speed of a variable damping coefficient damper that switches flow paths in response to pressure changes within the damper and piston displacement. The horizontal axis represents the absolute value of the response speed (mm / sec), and the vertical axis represents the absolute value of the damping force (kN).

[0021] The variable damping coefficient damper generates low damping force when the absolute value of the response speed is low. L High damping characteristics C, which shows high damping force when the absolute value of the response speed is high. H Shows.

[0022] A variable damping coefficient damper switches its damping characteristics at a constant response speed. The response speed for switching damping characteristics may have a range. The response speed at which the variable damping coefficient damper switches its damping characteristics when loaded is referred to as the characteristic switching speed V1. In this embodiment, the characteristic switching speed V1 may correspond to the boundary value between the response speed range for a level 2 earthquake motion and the response speed range for a level 3 earthquake motion. In other words, the characteristic switching speed V1 may be set to satisfy the following: (1) when a level 2 earthquake motion is input to the building 100, the response speed of the variable damping coefficient damper is less than the characteristic switching speed V1; and (2) when a level 3 earthquake motion is input, the response speed is equal to or greater than the characteristic switching speed V1. The characteristic switching speed V1 corresponds to the switching amount.

[0023] The variable damping coefficient damper has low damping characteristics C when loaded and at a characteristic switching speed less than V1. L At the characteristic switching speed V1, the low damping characteristic C L High attenuation characteristics C H At characteristic switching speeds of V1 and above, the high damping characteristic C H The damping force of the variable damping coefficient damper increases discontinuously (or discretely) at the characteristic switching speed V1. High damping characteristic C H The characteristic curve of the variable damping coefficient damper extends almost along the vertical axis at the characteristic switching speed V1. H is the first high attenuation characteristic C H 1 and 2 high attenuation characteristics C H 2. First high attenuation characteristic C H The damping coefficient of 1 is the second high damping characteristic C H 2. In other words, the damping characteristics of the variable damping coefficient damper are at least as high as the low damping characteristics C L Damping coefficient, first high damping characteristic C H Damping coefficient of 1 and high damping characteristic C H It has three damping factors, such as a damping factor of 2.

[0024] When loading, the variable damping coefficient damper switches to the first high damping characteristic C when the response speed is greater than the characteristic switching speed V1. H 1 and 2 high attenuation characteristics C H When the response speed reaches the characteristic switching speed V2, the damping force drops sharply, resulting in low damping characteristic C. L In this case, too, the damping force decreases discontinuously (or discretely) at the characteristic switching speed V2. The characteristic switching speed V2 is lower than the characteristic switching speed V1.

[0025] The table in Figure 3 shows the damping characteristics of a variable damping coefficient damper for each response speed and response displacement. A variable damping coefficient damper switches its damping characteristics at a certain characteristic switching displacement, just like the response speed. A variable damping coefficient damper exhibits low damping characteristics C only when the response speed is small compared to the characteristic switching speeds V1 and V2 and the response displacement is small compared to the characteristic switching displacement.L The variable damping coefficient damper has high damping characteristics C regardless of the response displacement when the response speed is higher than the characteristic switching speeds V1 and V2. H Furthermore, when the response displacement is large relative to the characteristic switching displacement, the variable damping coefficient damper maintains high damping characteristics regardless of the response speed.

[0026] 4 shows the damping characteristic C2 of the oil damper and the damping characteristic C3 (first damping characteristic) of the rotation amplification damper. The dashed line shows the damping characteristic C1 (second damping characteristic) of the variable damping coefficient damper.

[0027] Below the characteristic switching speed V1, the oil damper and rotation amplification damper generate a large damping force, while the variable damping coefficient damper suppresses the damping force. Above the characteristic switching speed V1, the variable damping coefficient damper generates a damping force similar to that generated by the oil damper, rotation amplification damper, and variable damping coefficient damper.

[0028] When designing using seismic isolation retrofitting methods that can maintain and preserve the appearance of existing buildings, or when designing seismic isolated buildings on narrow urban sites, it is expected that sufficient seismic isolation layer clearance cannot be secured due to site constraints. For example, in a seismic isolated building located on narrow land, the seismic isolation layer clearance may be around 35 cm.

[0029] On the other hand, in order to suppress excessive displacement of the seismic isolation layer 101 in response to a level 3 earthquake motion, it is necessary to add damping in the high velocity region. For a level 3 earthquake motion, the damping forces generated by oil dampers, rotational amplification dampers, and variable damping coefficient dampers show similar trends, so oil dampers, rotational amplification dampers, and variable damping coefficient dampers are all suitable as seismic isolation members.

[0030] However, if only oil dampers and rotation amplification dampers are placed in the seismic isolation layer 101, there is a possibility that over-damping will occur during a level 2 earthquake motion. On the other hand, variable damping coefficient dampers have a more complex configuration than at least oil dampers, and therefore, using variable damping coefficient dampers for all dampers 10 would cause inconveniences in construction conditions, including cost-effectiveness. For this reason, in the design system for seismic isolation structures, variable damping coefficient dampers are placed in the seismic isolation layer 101 in addition to oil dampers and rotational amplification dampers, with the aim of suppressing displacement of the seismic isolation layer 101 during level 3 earthquake motion and suppressing overdamping during level 2 earthquake motion.

[0031] (Design System) 5 shows the hardware configuration of one or more information processing devices H10 that constitute the design system for a seismic isolation structure. The information processing device H10 includes a communication device H12, an input device H14, a display device H15, a storage device H13, and a processor H11. Note that this hardware configuration is an example, and it can also be realized using other hardware or a combination of this hardware with other hardware.

[0032] The communication device H12 is an interface that establishes a communication path with another device and transmits and receives data. For example, the communication device H12 is a network interface that performs communication via the Internet or the like, either wired or wirelessly.

[0033] The input device H14 is a device that accepts input of various information based on operations by a person in charge. The input device H14 is, for example, a touch panel, a mouse, a keyboard, etc. The display device H15 is, for example, a display that displays various information. The input device H14 and the display device H15 may be provided in the information processing device H10 used by the user.

[0034] The storage device H13 (computer-readable medium) stores data and various programs for executing various functions. Examples of the storage device H13 include ROM, RAM, and a hard disk. The storage device H13 includes any available recording medium that can be accessed by a general-purpose or dedicated computer. The storage device H13 stores a design program and various data used to execute the program.

[0035] The processor H11 controls each process using programs and data stored in the storage device H13. Examples of the processor H11 include a CPU and an MPU. The processor H11 loads programs into RAM and executes various processes for each process. The processor H11 is not limited to a processor that performs software processing for all of the processes it executes. For example, the processor H11 may be equipped with a dedicated hardware circuit (e.g., an application-specific integrated circuit: ASIC) that performs hardware processing for at least some of the processes it executes. That is, the processor H11 may be configured as any of the following:

[0036] [1] One or more processors that operate according to a computer program (software). [2] One or more dedicated hardware circuits that perform at least some of the various processes [3] Circuits (circuits / circuitry) including combinations of these (Design system functions) With reference to FIG. 6, the functions of the design system 1 realized by executing a design program stored in the storage device H13 of the information processing device H10 and the data used by the design system 1 will be described.

[0037] The design system 1 includes a control unit 2, a damping characteristic storage unit 5, and a seismic wave storage unit 6. The control unit 2 includes a setting unit 3 and a response analysis unit 4. The damping characteristic storage unit 5 stores information indicating the damping characteristics of the oil damper, the rotation amplification damper, and the variable damping coefficient damper.

[0038] The earthquake wave storage unit 6 stores earthquake waves for inputting earthquake motion into the analysis model of the building 100. The earthquake wave storage unit 6 stores earthquake waves for inputting earthquake motion of level 2 and earthquake waves for inputting earthquake motion of level 3. The earthquake waves are notice waves, site waves, etc., which are simulated design earthquake waves that take into account the ground, etc.

[0039] The setting unit 3 sets an analytical model of the building 100. For example, the setting unit 3 uses a multi-mass system model including mass points and damper elements corresponding to each story as the analytical model. The setting unit 3 also sets performance indexes (criteria) for the building 100. At this time, the setting unit 3 may set a performance index for each level of seismic motion. The performance indexes include the upper limit of the target story shear force coefficient of the upper structure, the upper limit of the story displacement angle of the upper structure, and the maximum response speed of the damper 10. The story displacement is the horizontal displacement of each story relative to the story below when the building 100 deforms horizontally due to seismic force, and the story displacement angle indicates the ratio of the story displacement to the height of each floor.

[0040] Furthermore, the setting unit 3 sets a target value of the response displacement (seismic isolation layer displacement) in the seismic isolation layer 101 based on the seismic isolation layer clearance ensured in the building 100 as one of the performance indexes.

[0041] The response analysis unit 4 calculates the response when a level 2 earthquake motion is input and the response when a level 3 earthquake motion is input to the analytical model of the building 100 in which each damper 10 is arranged. The response analysis unit 4 also determines the number of each damper 10 so that the response satisfies the performance index of the building 100 and the target value of the seismic isolation layer displacement.

[0042] The response analysis unit 4 determines the number J of oil dampers and the number K of rotational amplification dampers so that the performance index of the building 100 is satisfied when a level 3 earthquake motion is input to the analysis model of the building 100 in which oil dampers and rotational amplification dampers are installed.

[0043] In addition, when level 2 earthquake motion is input to the analysis model of building 100 in which oil dampers and rotary amplification dampers are set, the response analysis unit 4 replaces some of the oil dampers and rotary amplification dampers with variable damping coefficient dampers so that the performance index of building 100 is met.

[0044] In addition, the response analysis unit 4 inputs level 3 earthquake motion into an analysis model in which some of the oil dampers and rotational amplification dampers have been replaced with variable damping coefficient dampers, and determines the number of oil dampers, rotational amplification dampers, and variable damping coefficient dampers so that the displacement of the seismic isolation layer is below the target value.

[0045] Furthermore, the response analysis unit 4 can change the characteristic switching speeds V1 and V2 of the variable damping coefficient damper within a predetermined range. <Operation of this embodiment> The operation of the system 1 for designing a seismic isolation structure will be described with reference to Figures 7 to 10. The order of each step can be changed as long as no contradiction occurs.

[0046] (Setting process) 7 shows the setting process that is performed before response analysis is performed. The setting unit 3 performs a basic plan (step S1). The setting unit 3 sets the plan shape, number of floors, and height (building height) of the analysis model based on information input by the user. The setting unit 3 also sets the structure type, such as reinforced concrete or steel structure.

[0047] The setting unit 3 sets performance indexes for level 2 (L2) earthquake motion and level 3 (L3) earthquake motion (step S2). At this time, the setting unit 3 sets the upper limit value of the target story shear force coefficient of the superstructure, the upper limit value of the story displacement angle of the superstructure, and the maximum response speed of the damper 10, as well as the target value of the seismic isolation layer displacement.

[0048] The setting unit 3 also sets the restoring force characteristics of the seismic isolation layer 101 (step S3). Specifically, the setting unit 3 sets the story shear force coefficient of the yield point of the seismic isolation layer 101. (Response analysis processing) Next, the response analysis process will be described with reference to Figures 8 to 10. The response analysis process is made up of a first response analysis process S5, a second response analysis process S20, and a third response analysis process S30. Figure 8 shows the first response analysis process S5. The first response analysis process S5 is a process in which a level 3 earthquake motion is input into an analysis model to perform a time history response analysis.

[0049] In the first response analysis process S5, the response analysis unit 4 sets the numbers J and K of dampers 10 for level 3 earthquake motion via the setting unit 3 (step S10). Here, the response analysis unit 4 sets the number J of oil dampers and the number K of rotational amplification dampers. At this time, the number of variable damping coefficient dampers is set to "0".

[0050] The response analysis unit 4 inputs a level 3 earthquake motion into the analysis model and performs a time history response analysis (step S11). The response analysis unit 4 then determines whether the results of the time history response analysis satisfy the performance index (step S12). At this time, the response analysis unit 4 may also determine whether the performance index is satisfied, including whether the seismic isolation layer displacement is equal to or less than the target value. Alternatively, the response analysis unit 4 may determine a performance index other than the seismic isolation layer displacement. For example, the response analysis unit 4 determines whether the target story shear force coefficient included in the analysis result is equal to or less than the upper limit value of the performance index.

[0051] If the response analysis unit 4 determines that the result of the time history response analysis does not satisfy the performance index (step S12: NO), it increases the number of dampers 10 via the setting unit 3 (step S13). The response analysis unit 4 increases the number J of oil dampers (J → J+1) and / or increases the number K of rotational amplification dampers (K → K+1). At this time, the response analysis unit 4 may alternately increase the number J of oil dampers (J → J+1) and increase the number K of rotational amplification dampers (K → K+1) each time step S13 is performed. Alternatively, the response analysis unit 4 may both increase the number J of oil dampers (J → J+1) and increase the number K of rotational amplification dampers (K → K+1).

[0052] Then, the response analysis unit 4 repeats the time history response analysis (step S11) in which a level 3 earthquake motion is input, and the increase in the number of dampers 10 (step S13) until the performance index is satisfied. If the response analysis unit 4 determines that the performance index for the level 3 earthquake motion is satisfied (step S12: YES), it performs a second response analysis process S20 in which the level 2 earthquake motion is input into the analysis model and a time history response analysis is performed.

[0053] The second response analysis process (step S20) will be described with reference to FIG. 9. The response analysis unit 4 sets the number of dampers 10 for Level 2 earthquake motion via the setting unit 3 (step S21). Specifically, the response analysis unit 4 replaces either the oil dampers or the rotational amplification dampers set in the first response analysis process with variable damping coefficient dampers. Specifically, the response analysis unit 4 decrements the total number of oil dampers and rotational amplification dampers (J+K) by (J+K-1), and increments the number of variable damping coefficient dampers, for example, by "1 unit." The dampers 10 to be replaced from among the oil dampers and rotational amplification dampers may be selected based on priorities such as cost.

[0054] The response analysis unit 4 inputs the level 2 earthquake motion into the analysis model and performs a time history response analysis (step S22). The response analysis unit 4 then determines whether the result of the time history response analysis satisfies the performance index (step S23). At this time, the response analysis unit 4 determines performance indexes other than the seismic isolation layer displacement.

[0055] If the response analysis unit 4 determines that the results of the time history response analysis do not satisfy the performance index (step S23: NO), it replaces either the oil dampers or the rotational amplifier dampers with variable damping coefficient dampers via the setting unit 3 (step S24). For example, the response analysis unit 4 decrements (J+K-1) the total number of oil dampers and rotational amplifier dampers, and increments (M+1) the number of variable damping coefficient dampers. The response analysis unit 4 places variable damping coefficient dampers at the locations where the oil dampers and rotational amplifier dampers to be replaced are installed, but the locations of the variable damping coefficient dampers may be changed.

[0056] Then, the response analysis unit 4 repeats the time history response analysis (step S22) of inputting level 2 earthquake motion and the replacement of either the oil damper or the rotational amplification damper with the variable damping coefficient damper (step S24) until the performance index for level 2 earthquake motion is satisfied.

[0057] When the response analysis unit 4 determines that the analysis result satisfies the performance index for level 2 earthquake motion (step S23: YES), it performs a third response analysis process (step S30) to determine whether the seismic isolation clearance satisfies the target value.

[0058] The third response analysis process (step S30) will be described with reference to Fig. 10. The response analysis unit 4 inputs a level 3 earthquake motion into the analysis model and performs a time history response analysis (step S31). The response analysis unit 4 acquires the seismic isolation layer displacement when the level 3 earthquake motion is input, and determines whether the seismic isolation layer displacement is equal to or less than a target value (step S32).

[0059] When the response analysis unit 4 determines that the seismic isolation layer displacement is equal to or less than the target value (step S32: YES), it determines that seismic isolation clearance can be ensured even during a level 3 earthquake motion, and ends the process. On the other hand, if the response analysis unit 4 determines that the seismic isolation layer displacement exceeds the target value (step S32: NO), it determines whether or not it is necessary to reset the characteristic switching speed of the variable damping coefficient damper (step S33). In other words, the response analysis unit 4 determines whether or not it is possible to further replace either the oil damper or the rotation amplification damper with a variable damping coefficient damper.

[0060] For example, the maximum number of variable damping coefficient dampers that can be replaced may be set in advance. For example, the analysis model may be set to a condition that a predetermined number or more of oil dampers and rotation amplification dampers are to be set. The response analysis unit 4 determines whether or not it is necessary to reset the characteristic switching speed based on the preset replacement condition.

[0061] If the oil damper and rotational amplification damper cannot be replaced with a variable damping coefficient damper, the response analysis unit 4 determines that the characteristic switching speeds V1 and V2 of the variable damping coefficient damper need to be reset (step S33: YES). The response analysis unit 4 resets the characteristic switching speeds (step S34). At this time, the response analysis unit 4 may set the characteristic switching speeds V1 and V2 via the setting unit 3 to be smaller, so that the damping force is increased at a response speed smaller than before the setting. Alternatively, the response analysis unit 4 may set the characteristic switching speeds V1 and V2 via the setting unit 3 to be larger, so that the damping force is increased at a response speed larger than before the setting.

[0062] After changing the characteristic switching speeds V1 and V2, the response analysis unit 4 repeats the second response analysis (step S20) described above. On the other hand, if the response analysis unit 4 determines that it is not necessary to reset the characteristic switching speeds V1 and V2 of the variable damping coefficient dampers (step S33: NO), it resets the numbers of oil dampers, rotational amplifier dampers, and variable damping coefficient dampers (step S35). For example, the response analysis unit 4 may increase the number of at least one of oil dampers, rotational amplifier dampers, and variable damping coefficient dampers. In addition to or instead of this, the response analysis unit 4 may change the ratio of the numbers of oil dampers, rotational amplifier dampers, and variable damping coefficient dampers.

[0063] After the response analysis unit 4 performs the resetting in step S35, it repeats the second response analysis (step S20) described above. In this way, the response analyzing unit 4 repeats the first response analyzing process, the second response analyzing process, and the third response analyzing process until the performance index is satisfied.

[0064] <Effects of this embodiment> As described above, according to the above embodiment, the following effects can be obtained. (1) According to the above embodiment, the design system 1 sets oil dampers and rotational amplification dampers in the analysis model, and after setting them so that the response analysis when a level 3 earthquake motion is input satisfies the performance index, some of them are replaced with variable damping coefficient dampers. This makes it possible to design a seismic isolation structure that controls the response of the building 100 within an appropriate range, regardless of the level of a major earthquake. In other words, even if there are strict constraints on seismic isolation clearance, such as in narrow areas, it is possible to minimize the decrease in seismic isolation effect during a level 2 earthquake motion while keeping the seismic isolation displacement during a level 3 earthquake motion below the target value.

[0065] (2) According to the above embodiment, the design system 1 can change the characteristic switching speeds V1 and V2 of the variable damping coefficient damper within a predetermined range. This makes it possible to design variable damping coefficient dampers that are tailored to the building 100, in addition to the number of dampers 10. As a result, it becomes easier to achieve the desired seismic isolation effect.

[0066] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0067] (Damper) In the above embodiment, the dampers 10 used in the base isolation layer 101 are exemplified as oil dampers and rotational amplification dampers, but the types are not limited thereto. As the dampers 10 used in the base isolation layer 101, viscous damping dampers other than oil dampers and rotational amplification dampers may be used in addition to or instead of the oil dampers and rotational amplification dampers. Alternatively, in addition to or instead of the oil dampers and rotational amplification dampers, hysteresis damping dampers that utilize plastic deformation energy of metals, Coulomb friction energy, or a combination of these may be used.

[0068] (Design method) In the above embodiment, the first response analysis process was performed to set the number of oil dampers and rotary amplifier dampers to satisfy the performance index for Level 3 earthquake motion, followed by the second response analysis process to replace the oil dampers and rotary amplifier dampers with variable damping coefficient dampers. The order in which the numbers of dampers 10 are set is not limited as long as the performance index for Level 2 earthquake motion, the performance index for Level 3 earthquake motion, and the target seismic isolation displacement are ultimately satisfied. For example, the response analysis unit 4 may first set the number of oil dampers and rotary amplifier dampers to satisfy the performance index for Level 3 earthquake motion, then perform the third response analysis process to input Level 3 earthquake motion and reduce the seismic isolation displacement to the target value or less, and then perform the second response analysis process.

[0069] The setting unit 3 may perform setting for wind load as a setting process. Specifically, the setting unit 3 determines an appropriate rank from three ranks regarding the behavior of the seismic isolation layer 101 against wind load defined in the Seismic Design Guidelines for Base-Isolated Buildings.

[0070] The response analysis unit 4 is configured to change the characteristic switching speeds V1 and V2 of the variable damping coefficient damper when the seismic isolation layer displacement included in the analysis results when a level 3 earthquake motion is input is equal to or less than the target value. Alternatively, the response analysis unit 4 may change either the characteristic switching speed V1 during loading or the characteristic switching speed V2 during unloading.

[0071] The response analysis unit 4 is configured to change the characteristic switching speeds V1 and V2 of the variable damping coefficient dampers when the seismic isolation layer displacement included in the analysis results when a level 3 earthquake motion is input is equal to or less than a target value. Alternatively or additionally, in the second response analysis process, the response analysis unit 4 may determine whether the analysis results satisfy the performance index (step S23), and if the analysis results do not satisfy the performance index, may change the characteristic switching speeds V1 and V2 in addition to changing the number of variable damping coefficient dampers.

[0072] (Attenuation characteristics) In the above embodiment, the characteristic switching speeds V1 and V2 are set to values ​​near the boundary between the response speed when a level 2 earthquake motion is input and the response speed when a level 3 earthquake motion is input. The characteristic switching speeds V1 and V2 may be any response speed at which overdamping is likely to occur in the base isolation layer 101 in which only the first velocity-dependent damper is arranged. The characteristic switching speeds V1 and V2 do not necessarily have to be the boundary values ​​between the response speed when a level 2 earthquake motion is input and the response speed when a level 3 earthquake motion is input.

[0073] In the above embodiment, the damper 10 is a velocity-dependent damper, and the switching amount of the response amount is the switching speed of the response speed. In the above embodiment, the "response speed" corresponds to the response amount in the claims, and the "characteristic switching speed" corresponds to the switching amount in the claims. Alternatively or additionally, the damper 10 provided in the seismic isolation layer 101 may be a displacement-dependent damper. When a variable damping coefficient damper corresponding to the second damper rapidly changes the damping force at a predetermined response displacement as the response displacement increases, the characteristic switching displacement is a response displacement that is approximately the boundary between the response displacement at a level 2 earthquake motion and the response displacement at a level 3 earthquake motion. Note that a variable damping coefficient damper that rapidly changes the damping force depending on the displacement may switch the damping characteristics by opening and closing an adjustment valve or relief valve provided on the piston, or by switching the flow path in response to the piston displacement. In the displacement-dependent damper 10, the "response displacement" corresponds to the response amount in the claims, and the "characteristic switching displacement" corresponds to the switching amount in the claims.

[0074] Next, the technical ideas that can be understood from the above-described embodiment and other examples will be described below. [A] A design system for a seismic isolation structure as described in claim 1, wherein a plurality of types of dampers are used as the first dampers, and when replacing some of the first dampers with the second dampers, any of the plurality of types of dampers is replaced with the second damper. [Explanation of symbols]

[0075] 1...design system, 2...control unit, 3...setting unit, 4...response analysis unit, 5...damping characteristic memory unit, 6...seismic wave memory unit, 10...damper

Claims

1. A design system for a seismic isolation structure includes a damping characteristic memory unit that stores the damping characteristics of dampers placed in the seismic isolation layer of a building, and a control unit that performs response analysis, The attenuation characteristic storage unit Information regarding a first damping characteristic of the first damper; and information relating to the second damping characteristic of the second damper; the first damping characteristic gradually or stepwise reduces the damping coefficient as the response amount increases, The second damping characteristic is such that the damping force is suddenly increased at a switching amount which is a predetermined response amount as the response amount increases, The control unit determining the number of the first dampers so that a performance index of the building is satisfied when a level 3 earthquake motion is input to an analysis model of the building in which the first dampers are set; When a level 2 earthquake motion is input to the analysis model of the building in which the first damper is set, a part of the first damper is replaced with the second damper so that the performance index of the building is satisfied; A design system for a seismic isolation structure that inputs level 3 earthquake motion into the analysis model in which some of the first dampers have been replaced with the second dampers, and determines the number of the first dampers and the second dampers so that the displacement of the seismic isolation layer is below a target value.

2. The control unit The system for designing a seismic isolation structure according to claim 1 , wherein the switching amount of the second damper is changed when the seismic isolation layer displacement exceeds the target value.

3. A method for designing a seismic isolation structure using a damping characteristic storage unit that stores the damping characteristics of dampers placed in the seismic isolation layer of a building and a control unit that performs response analysis, The attenuation characteristic storage unit Information regarding a first damping characteristic of the first damper; and information relating to the second damping characteristic of the second damper; the first damping characteristic gradually or stepwise reduces the damping coefficient as the response amount increases, The second damping characteristic is such that the damping force is suddenly increased at a switching amount which is a predetermined response amount as the response amount increases, The control unit determining the number of the first dampers so that a performance index of the building is satisfied when a level 3 earthquake motion is input to an analysis model of the building in which the first dampers are set; When a level 2 earthquake motion is input to the analysis model of the building in which the first damper is set, a part of the first damper is replaced with the second damper so that the performance index of the building is satisfied; A design method for a seismic isolation structure, in which a level 3 earthquake motion is input to the analysis model in which some of the first dampers have been replaced with the second dampers, and the number of the first dampers and the second dampers is determined so that the displacement of the seismic isolation layer is below a target value.

4. A program for designing a seismic isolation structure using a damping characteristic storage unit that stores the damping characteristics of dampers placed in the seismic isolation layer of a building and a control unit that performs response analysis, The attenuation characteristic storage unit Information regarding a first damping characteristic of the first damper; and information relating to the second damping characteristic of the second damper; the first damping characteristic is a characteristic in which the damping coefficient is gradually or stepwise decreased as the response amount increases, The second damping characteristic is such that the damping force is suddenly increased at a switching amount which is a predetermined response amount as the response amount increases, The control unit determining the number of the first dampers so that a performance index of the building is satisfied when a level 3 earthquake motion is input to an analysis model of the building in which the first dampers are set; When a level 2 earthquake motion is input to the analysis model of the building in which the first damper is set, a part of the first damper is replaced with the second damper so that the performance index of the building is satisfied; A design program for a seismic isolation structure that functions as a means for inputting level 3 seismic motion into the analysis model in which some of the first dampers have been replaced with the second dampers, and determining the number of the first dampers and the second dampers so that the displacement of the seismic isolation layer is below a target value.

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