Method and system for measuring damage of building caused by earthquake

Abstract

The present invention has an objective of providing a measurement method capable of precisely and easily measuring the degree of damage of a building caused by an earthquake. The present invention is a measurement method for damage of a building caused by an earthquake, the method involving obtaining the degree of the damage of the building on the basis of a heat quantity of a structure component of the building.

Description

Earthquake damage measurement method and system

[0001] The present invention relates to a method for measuring damage to a structure caused by an earthquake and a system for measuring damage to a structure caused by an earthquake.

[0002] Structural health monitoring, which involves installing sensors in structural members that make up a building or civil engineering structure (hereinafter also referred to as a "building") and determining the degree of damage to the building due to an earthquake based on information from the sensors, and detecting damage and evaluating the soundness of the building, has attracted attention. For example, Patent Document 1 proposes an estimation system and estimation method that uses physical sensors such as acceleration sensors and strain gauges to estimate the damage status of a building due to an earthquake.

[0003] Japanese Patent Application Laid-Open No. 2020-128951

[0004] In conventional methods using acceleration sensors, even if the acceleration sensor is installed on a structural member, vibrations other than those of the structural member itself (such as vibrations of other structural members around the structural member) are reflected in the measurement. Therefore, while the method using acceleration sensors needs to take into account vibrations other than those of the structural member itself when measuring damage to a building, it requires simulation calculations each time a measurement is made, which results in a complex analysis. Furthermore, the method using strain gauges has the problem of low accuracy in measuring damage to a building.

[0005] Therefore, an object of the present invention is to provide a measurement method that can easily and accurately measure the degree of earthquake damage to a structure, and a measurement system that can easily and accurately measure the degree of earthquake damage to a structure.

[0006] The present inventors have newly discovered that the above-mentioned problems can be solved by determining the degree of damage to a building based on the heat quantity of the structural members that make up the building, and have completed the present invention.

[0007]

[0010] The present invention aims to advantageously solve the above problems, and provides a method for measuring earthquake damage to a structure, which determines the degree of damage to the structure based on the heat quantity of structural members that make up the structure. Such a measurement method makes it possible to accurately and easily measure the degree of earthquake damage to a structure.

[0008] [2] In the measurement method of [1] above, it is preferable that the heat quantity includes the amount of plastic heat generation and the amount of heat generated by the thermoelastic effect, and the degree of damage is determined using the cumulative plastic strain of the structural member calculated from the amount of plastic heat generation and the number of elastic vibrations calculated from the amount of heat generated by the thermoelastic effect. If the degree of damage is determined using the cumulative plastic strain and the number of elastic vibrations, the degree of damage to the structure caused by the earthquake can be measured with greater accuracy.

[0009] [3] In the measurement method of [1] or [2] above, it is preferable to determine the heat quantity from the temperature change of the structural member. If the heat quantity is determined from the temperature change of the structural member, the degree of damage to the structure caused by the earthquake can be measured with higher accuracy. Furthermore, since temperature is easy to measure, the degree of damage to the structure caused by the earthquake can be measured more simply.

[0010] [4] In the measurement method according to any one of the above [1] to [3], the structural member is preferably a damper. If the structural member is a damper, the degree of damage to the building caused by the earthquake can be measured with higher accuracy.

[0011] [5] In any of the measurement methods [1] to [4] above, it is preferable that the heat quantity is determined by a temperature sensor installed in the structural member. If the heat quantity is determined by a temperature sensor installed in the structural member, the degree of damage to the building caused by the earthquake can be measured more accurately and easily. In addition, since the temperature sensor can measure the temperature in a short time, power consumption can be reduced.

[0012] [6] In the measurement method of [5] above, it is preferable that the temperature sensor is operated by the energy of the earthquake. If the temperature sensor is operated by the energy of the earthquake, it is possible to reduce the amount of electricity used.

[0013] [7] In the measurement method of [5] or [6] above, the temperature sensor is preferably a thermoelectric conversion element. If the temperature sensor is a thermoelectric conversion element, the degree of damage to the structure caused by the earthquake can be measured with greater accuracy. Furthermore, if the temperature sensor is a thermoelectric conversion element, it can also be used as a power source.

[0014] [8] In the measurement method of [7] above, the thermoelectric conversion element is preferably flexible. If the thermoelectric conversion element is flexible, the risk of measurement becoming impossible due to vibration of structural members can be reduced, and measurement can be performed over a long period of time.

[0015] [9] In the measurement method of [7] or [8] above, it is preferable that the thermoelectric conversion element comprises a semiconductor containing carbon nanotubes. If the thermoelectric conversion element comprises a semiconductor containing carbon nanotubes, the degree of damage to a building caused by an earthquake can be measured with greater accuracy. Furthermore, if the thermoelectric conversion element comprises a semiconductor containing carbon nanotubes, the risk of measurement becoming impossible due to vibration of structural members can be reduced, making it possible to perform measurements over a long period of time.

[0016]

[10] In the measurement method of [9] above, the carbon nanotubes preferably include single-walled carbon nanotubes. If the carbon nanotubes include single-walled carbon nanotubes, the degree of damage to the structure caused by the earthquake can be measured with even greater accuracy.

[0017]

[11] In any of the measurement methods [5] to

[10] above, it is preferable to further use a sensor different from the temperature sensor. By using a sensor different from the temperature sensor, the degree of damage to the structure caused by the earthquake can be measured with even greater accuracy.

[0018]

[12] In any of the measurement methods [1] to

[11] above, it is preferable to use a communication system that transmits the heat quantity data to an external device. By using a communication system that transmits the heat quantity data to an external device, the degree of damage to a building caused by an earthquake can be measured more easily.

[0019]

[13] In the measurement method of

[12] above, the communication system is preferably a wireless communication system. If the communication system is a wireless communication system, the degree of damage to the structure caused by the earthquake can be measured more easily.

[0020] Another object of the present invention is to advantageously solve the above-mentioned problems, and

[14] the present invention is a measurement system for earthquake damage to a structure, comprising a measurement unit that acquires data on the heat quantity of structural members that make up the structure, and a calculation unit that calculates the degree of damage to the structure based on the heat quantity. Such a measurement system can accurately and easily measure the degree of earthquake damage to a structure.

[0021]

[15] In the measurement system of

[14] above, it is preferable that the heat quantity includes a plastic heat quantity and a heat quantity due to a thermoelastic effect, and the degree of damage is calculated using the cumulative plastic strain of the structural member calculated from the plastic heat quantity and the number of elastic vibrations calculated from the heat quantity due to the thermoelastic effect. If the degree of damage is calculated using the cumulative plastic strain and the number of elastic vibrations, the degree of damage to the structure due to an earthquake can be measured with higher accuracy.

[0022]

[16] In the measurement system of

[14] or

[15] above, it is preferable that the heat quantity is determined from the temperature change of the structural member. By determining the heat quantity from the temperature change of the structural member, the degree of damage to the structure caused by the earthquake can be measured with higher accuracy. Furthermore, since temperature is easy to measure, the degree of damage to the structure caused by the earthquake can be measured more simply.

[0023]

[17] In the measurement system of any one of

[14] to

[16] above, the structural member is preferably a damper. If the structural member is a damper, the degree of damage to the building caused by an earthquake can be measured with higher accuracy.

[0024]

[18] In the measurement system of any of

[14] to

[17] above, it is preferable that the measurement unit includes a temperature sensor installed in the structural member. If the measurement unit includes a temperature sensor installed in the structural member, the degree of damage to the building caused by the earthquake can be measured more accurately and easily. In addition, since the temperature sensor can measure the temperature in a short time, power consumption can be reduced.

[0025]

[19] In the measurement system of

[18] above, it is preferable that the temperature sensor is operated by the energy of the earthquake. If the temperature sensor is operated by the energy of the earthquake, the amount of electricity used can be reduced.

[0026]

[20] In the measurement system of

[18] or

[19] above, the temperature sensor is preferably a thermoelectric conversion element. If the temperature sensor is a thermoelectric conversion element, the degree of damage to the structure caused by the earthquake can be measured with greater accuracy. Furthermore, if the temperature sensor is a thermoelectric conversion element, it can also be used as a power source.

[0027]

[21] In the measurement system of

[20] above, the thermoelectric conversion element is preferably flexible. If the thermoelectric conversion element is flexible, the risk of measurement becoming impossible due to vibration of structural members can be reduced, and measurement over a long period of time can be made possible.

[0028]

[22] In the measurement system of

[20] or

[21] above, the thermoelectric conversion element preferably comprises a semiconductor containing carbon nanotubes. If the thermoelectric conversion element comprises a semiconductor containing carbon nanotubes, the degree of damage to a building caused by an earthquake can be measured with greater accuracy. Furthermore, if the thermoelectric conversion element comprises a semiconductor containing carbon nanotubes, the risk of measurement becoming impossible due to vibration of structural members can be reduced, making it possible to perform measurements over a long period of time.

[0029]

[23] In the measurement system of

[22] above, the carbon nanotubes preferably include single-walled carbon nanotubes. If the carbon nanotubes include single-walled carbon nanotubes, the degree of damage to the structure caused by the earthquake can be measured with even greater accuracy.

[0030]

[24] In the measurement system of any of

[18] to

[23] above, it is preferable that the measurement unit further includes a sensor different from the temperature sensor. If the measurement unit further includes a sensor different from the temperature sensor, the degree of damage to the structure due to the earthquake can be measured with even greater accuracy.

[0031]

[25] Preferably, the measurement system of any one of

[14] to

[24] above further comprises a communication unit having a communication system for transmitting the heat quantity data to the outside. By further comprising a communication unit having a communication system for transmitting the heat quantity data to the outside, the degree of damage to the structure caused by the earthquake can be measured more easily.

[0032]

[26] In the measurement system of

[25] above, the communication system is preferably a wireless communication system. If the communication system is a wireless communication system, the degree of damage to the structure caused by the earthquake can be measured more easily.

[0033] According to the present invention, it is possible to provide a measurement method that can easily and accurately measure the degree of damage to a structure caused by an earthquake. Also, according to the present invention, it is possible to provide a measurement system that can easily and accurately measure the degree of damage to a structure caused by an earthquake.

[0034] FIG. 1 is an example of a graph that schematically shows temperature changes in structural members during an earthquake. FIG. 2 is a graph that shows an enlarged view of the graph shown in FIG. 1 at the early stage of an earthquake. FIG. 3 is a graph that schematically shows the temperature changes in the graph shown in FIG. 2 separated into temperature changes due to plastic heat generation and temperature changes due to the heat generation of thermoelastic effects. FIG. 4 is a schematic diagram showing an example of a building that includes a damper in which a temperature sensor is installed. FIG. 5 is a block diagram showing an example of a measurement system of the present invention. FIG. 6 is a block diagram showing an example of a measurement system of the present invention. FIG. 7 is a schematic diagram for explaining a test method for Test Example 1. FIG. 8 is a schematic diagram for explaining a test method for Test Example 4. FIG. 9 is a schematic diagram for explaining a test method for Test Example 5.

[0035] Hereinafter, embodiments of the present invention will be described in detail.

[0036] (Method for Measuring Earthquake-Induced Damage to Structures) The method for measuring earthquake-induced damage to structures (hereinafter simply referred to as the "measurement method") of the present invention determines the degree of damage to a structure based on the heat content of the structural members that make up the structure. This measurement method allows for accurate and simple measurement of the degree of earthquake-induced damage to a structure. This is presumably due to the correlation between the degree of damage to a structure and the strain of the structural members, and the correlation between the strain of the structural members and the heat content. In other words, since there is a correlation between the degree of damage to a structure, the strain of the structural members, and the heat content of the structural members, the degree of damage to a structure can be determined based on changes in the heat content of the structural members due to vibrations caused by an earthquake. Furthermore, the heat content of structural members is not easily affected by surrounding members or the environment, so it can be determined accurately and simply. Therefore, using this heat content to determine the degree of damage allows for accurate and simple measurement of the degree of earthquake-induced damage to a structure.

[0037] In the measurement method of the present invention, the heat quantity of a structural member is not particularly limited as long as it is a calculation method that can determine the heat quantity or a measurement method that can measure the heat quantity, but it is preferable to determine it from the temperature change of the structural member. If the heat quantity is determined from the temperature change of the structural member, the degree of damage to the structure caused by the earthquake can be measured more accurately. Furthermore, because temperature is easy to measure, the degree of damage to the structure caused by the earthquake can be measured more simply.

[0038] In the measurement method of the present invention, the heat quantity of the structural member includes the amount of plastic heat generation and the amount of heat generation due to the thermoelastic effect, and the degree of damage is preferably determined using the cumulative plastic strain of the structural member calculated from the amount of plastic heat generation and the number of elastic vibrations calculated from the amount of heat generation due to the thermoelastic effect. Determining the degree of damage using the cumulative plastic strain and the number of elastic vibrations allows for more accurate and convenient measurement of the degree of earthquake-induced damage to the building. Specifically, the amount of plastic heat generation (cumulative plastic strain) can be used to evaluate the magnitude of the earthquake and the extent of damage to the building (structural member), while the amount of heat generation due to the thermoelastic effect (number of elastic vibrations) can be used to predict damage to the building (structural member) due to future earthquakes (e.g., how many more earthquakes of magnitude 5+ it will take for the building to collapse), thereby enabling more accurate measurement of the degree of earthquake-induced damage to the building.

[0039] An example of a method for calculating cumulative plastic strain and the number of elastic vibrations when calculating heat quantity from temperature changes of structural members will be described below with reference to Figures 1 to 3. Here, Figure 1 is an example of a graph that schematically shows temperature changes of structural members during an earthquake, Figure 2 is a graph that shows an enlarged view of the graph shown in Figure 1 at the beginning of the earthquake, and Figure 3 is a graph that schematically shows the temperature changes in the graph shown in Figure 2 separated into temperature changes due to plastic heat generation and temperature changes due to the heat quantity of the thermoelastic effect.

[0040] As shown in Figure 1, the temperature of structural components during an earthquake rises with repeated small, periodic temperature changes (see also Figure 2). Once the earthquake stops (i.e., the structural components cease vibrating), the temperature returns to the temperature at the time of the earthquake (usually room temperature). As shown in Figure 3, the temperature change A (temperature rise) of a structural component includes a temperature change B due to the plastic heat generation of the structural component and a temperature change C due to the heat generation caused by the thermoelastic effect of the structural component. As mentioned above, there is a correlation between the strain and heat generation of a structural component, so there is also a correlation between the cumulative plastic strain of a structural component and the plastic heat generation of the structural component. Therefore, the plastic heat generation of a structural component can be calculated from the temperature change B, and the cumulative plastic strain of a structural component can be calculated from this plastic heat generation. On the other hand, since the temperature change C is due to the heat generation caused by the thermoelastic effect of the structural component, i.e., the compression (contraction) and tension (expansion) of the structural component, the number of elastic vibrations of a structural component can be calculated by integrating the number of periods (cycles) of the temperature change C. Temperature change B can be calculated by calculating the average value of temperature change A for each cycle and connecting these values ​​with a straight line. Temperature change C can be calculated from the difference between temperature change A and temperature change B ("temperature change A" - "temperature change B"). The cumulative plastic strain of a structural member can be calculated, for example, by calculating the amount of energy absorption (amount of plastic heat generation) from temperature change B (temperature rise) of the structural member through inverse analysis of heat conduction analysis, and then appropriately using the restoring force characteristics and flatness of the cross section of the structural member. The number of elastic vibrations of a structural member can be calculated, for example, from the number of cycles of temperature change C until the temperature rise of the structural member stops (in other words, until the temperature drop of the structural member begins).

[0041] To determine the degree of damage, it is preferable to further use the plastic strain amplitude for each half cycle of the elastic vibration of the structural member. If the degree of damage is further determined using the plastic strain amplitude, the degree of damage to the building caused by the earthquake can be measured with greater accuracy. The plastic strain amplitude for each half cycle can be determined by calculating each half cycle time from the elastic vibration cycle and dividing the cumulative plastic strain by the half cycle time.

[0042] Here, in the above, the amount of heat is calculated from the temperature change, but in addition to the temperature change, the amount of heat of the structural member can also be calculated from the amount of power generated by a thermoelectric conversion element or the like, which will be described later.

[0043] <Structural Members> In the measurement method of the present invention, the structural members are not particularly limited as long as they constitute a building, and examples thereof include pillars, beams, braces, walls, roofs, and foundations of a building. Examples of structural members also include seismic isolation members such as dampers installed midway between braces and the like, and bearings (isolators) installed below pillars and foundations. Here, dampers are components that prevent damage to pillars, beams, braces, and the like by absorbing the energy of earthquake impacts and vibrations, and include viscoelastic dampers and elasto-plastic dampers (hysteretic dampers). Among the structural members described above, dampers are preferred, and elasto-plastic dampers are more preferred, because they enable more accurate measurement of the degree of earthquake damage to a building.

[0044] In the measurement method of the present invention, the material of the structural member is not particularly limited, but examples include metals such as iron, copper, steel, and stainless steel, resins such as rubber, wood, etc. Among these, metals are preferred, and steel is more preferred, as they allow for more accurate measurement of the degree of damage to the structure due to an earthquake.

[0045] <Temperature Sensor> In the measurement method of the present invention, it is preferable to determine the heat quantity of a structural member using a temperature sensor. Because a temperature sensor can measure temperature in a short time, using a temperature sensor can reduce power consumption. It is more preferable to determine the heat quantity of a structural member using a temperature sensor installed on the structural member. If the heat quantity of a structural member is determined using a temperature sensor installed on the structural member, the degree of damage to a building caused by an earthquake can be measured more accurately and easily. It is even more preferable to determine the heat quantity of a structural member using a temperature sensor installed on the surface of the structural member. If the heat quantity of a structural member is determined using a temperature sensor installed on the surface of the structural member, the degree of damage to a building caused by an earthquake can be measured more accurately. Furthermore, because a temperature sensor can be easily installed on the surface of a structural member, the degree of damage to a building caused by an earthquake can be measured more easily. When a temperature sensor is used, a detector that detects the electrical output of the temperature sensor and a power source for operating the temperature sensor and the detector are generally used.

[0046] An example of the location of a temperature sensor when the structural member is a damper will be described below with reference to Fig. 4. Fig. 4 is a schematic diagram showing an example of a building equipped with a damper equipped with a temperature sensor. As shown in Fig. 4, a building 10 includes a foundation 11, a column 12 located on the foundation 11, a beam 13 lying on the column 12, and a diagonal brace 14 provided between the two columns 12. A damper 15 is provided midway between the brace 14, and a temperature sensor 16 is provided in the damper 15.

[0047] It is preferable that the temperature sensor be powered by earthquake energy, as this reduces the amount of power used. Note that the energy generated by an earthquake includes not only vibrations but also various other energies such as heat generated by vibrations.

[0048] The temperature sensor is not particularly limited as long as it can measure temperature, but examples include thermoelectric conversion elements, integrated circuit temperature sensors (IC temperature sensors), thermistors, resistance temperature detectors (RTDs), contact temperature sensors such as metal thermocouples, and non-contact temperature sensors such as infrared thermometers. Among these, contact temperature sensors are preferred because they can more accurately measure the degree of damage to buildings caused by earthquakes, and thermoelectric conversion elements or metal thermocouples are more preferred. Thermoelectric conversion elements are particularly preferred because they can also be used as a power source. When using a thermoelectric conversion element as a power source, the voltage may be converted to a suitable voltage using a boost converter or the like. Here, the thermoelectric conversion element is a thermoelectric element that uses a combination of p-type and n-type semiconductors, and examples include those that include semiconductors containing inorganic materials such as bismuth-tellurium (Bi-Te), lead-tellurium (Pb-Te), and silicon-germanium (Si-Ge) (hereinafter also referred to as "inorganic thermoelectric conversion elements"). Furthermore, the thermoelectric conversion element may be one that includes a semiconductor (p-type semiconductor and / or n-type semiconductor) containing carbon nanotubes (hereinafter also referred to as "CNTs") (hereinafter also referred to as "CNT thermoelectric conversion elements"). The temperature sensors listed above may be used alone or in combination of two or more types.

[0049] The thermoelectric conversion element is preferably flexible. If the thermoelectric conversion element has flexibility, the durability of the thermoelectric conversion element can be improved. That is, the risk of measurement becoming impossible due to vibration of the structural members can be reduced, and measurement over a long period of time can be made possible.

[0050] The thermoelectric conversion element is preferably a CNT thermoelectric conversion element. If the thermoelectric conversion element is a CNT thermoelectric conversion element, the degree of damage to a building caused by an earthquake can be measured with even greater accuracy. Furthermore, since CNT thermoelectric conversion elements have excellent flexibility, the use of CNT thermoelectric conversion elements can reduce the risk of measurement becoming impossible due to vibration of structural members, making it possible to perform measurements over long periods of time. Here, carbon nanotubes have a structure in which graphene sheets are rolled into a cylindrical shape, and are broadly classified into single-walled CNTs and multi-walled CNTs based on the number of peripheral walls.

[0051] The temperature sensor is preferably in sheet form. If the temperature sensor is in sheet form, the risk of measurement becoming impossible due to damage to the temperature sensor caused by vibration of structural members can be reduced, and measurement can be performed over a longer period of time. If the temperature sensor is in sheet form, its thickness is preferably 10 mm or less, more preferably 5 mm or less, even more preferably 2 mm or less, and even more preferably 1 mm or less. If the thickness of the temperature sensor is equal to or less than the above upper limit, the risk of measurement becoming impossible due to damage to the temperature sensor caused by vibration of structural members can be further reduced, and measurement can be performed over a longer period of time. The thickness of the sheet-shaped temperature sensor is, for example, 0.1 mm or more, and may be 0.5 mm or more.

[0052] Here, the CNTs used in the CNT thermoelectric conversion element are not particularly limited, and single-walled CNTs and / or multi-walled CNTs can be used, but it is preferable that the CNTs include single-walled CNTs. This is because single-walled CNTs tend to have superior thermoelectric properties (Seebeck coefficient) compared to multi-walled CNTs, and therefore can generate a high electromotive force (voltage) due to temperature changes caused by shaking, and as a result, the degree of damage to buildings caused by earthquakes can be measured with even greater accuracy. In addition, as single-walled CNTs, CNTs manufactured in accordance with a method (Super Growth Method; see International Publication No. 2006 / 011655) in which raw material compounds and a carrier gas are supplied to a substrate having a catalyst layer for CNT production on its surface to synthesize CNTs by chemical vapor deposition (CVD), and a trace amount of oxidizing agent (catalytic activation material) is present in the system to dramatically improve the catalytic activity of the catalyst layer can be used (hereinafter, CNTs manufactured in accordance with this method may be referred to as "SGCNTs"). SGCNTs tend to have a higher Seebeck coefficient than other CNTs. Therefore, if CNTs contain SGCNTs, they can generate a higher electromotive force (voltage) due to temperature changes caused by shaking, and as a result, the degree of damage to buildings caused by earthquakes can be measured with particularly high accuracy.

[0053] The average diameter of the CNTs is preferably 0.5 nm or more, more preferably 1 nm or more, and preferably 15 nm or less, and more preferably 10 nm or less. Furthermore, it is preferable that the average diameter (Av) and diameter distribution (3σ) of the CNTs satisfy the relationship: 0.60 > "3σ / Av" > 0.20. The "average diameter (Av)" and "diameter distribution (3σ)" referred to here are the average value and standard deviation (σ) obtained by measuring the diameters (outer diameters) of 100 randomly selected CNTs using a transmission electron microscope, respectively, multiplied by 3. Note that the standard deviation in this specification is the sample standard deviation.

[0054] The BET specific surface area of ​​CNT is 600 m ２ / g or more, and ２ / g or more, and 1000m ２ If the BET specific surface area of ​​the CNT is equal to or greater than the lower limit, the bending resistance of the CNT thermoelectric conversion element can be improved. ２ / g or less, and ２ The BET specific surface area of ​​the CNT is the nitrogen adsorption specific surface area measured using the BET method.

[0055] The CNT preferably has a ratio of the G band peak intensity to the D band peak intensity (G / D ratio) in the Raman spectrum of 0.5 or more and 5.0 or less.

[0056] <Other Sensors> When a temperature sensor is used in the measurement method of the present invention, it is preferable to further use a sensor other than the temperature sensor (hereinafter also referred to as "other sensor"). If the other sensor is further used, the degree of damage to the structure due to the earthquake can be measured with even greater accuracy. Examples of other sensors include strain gauges, vibration sensors, velocity sensors, acceleration sensors, and sound sensors. Among these, strain gauges are preferred because of their excellent measurement accuracy of the number of elastic vibrations. The above-mentioned other sensors may be used alone or in combination of two or more types.

[0057] <Detector> The detector for detecting the electrical output value of the temperature sensor is not particularly limited, and a conventionally known detector can be used.

[0058] <Power Source> The power source used to operate the temperature sensor is not particularly limited, and examples include batteries such as primary batteries and secondary batteries; system power supplies supplied from commercial power distribution networks; and power sources using natural energy. Examples of power sources using natural energy include photovoltaic power generation elements that use light energy such as sunlight, vibration power generation elements that use vibration energy such as earthquakes, and thermoelectric conversion elements that use thermal energy such as earthquakes. Among these, vibration power generation elements and thermoelectric conversion elements are preferred because they can efficiently utilize energy from earthquakes. Thermoelectric conversion elements are particularly preferred because they can function as both a temperature sensor and a power source, i.e., they can generate electricity while measuring the temperature of structural components and function as a power source. Note that using only a thermoelectric conversion element as a power source may prevent the temperature of structural components from being measured until power generation begins (until the temperature of the structural components rises). In this case, the degree of damage to the structure during the entire earthquake can be measured by predicting the temperature change measured before power generation begins from the temperature change after power generation begins. The power sources listed above may be used alone or in combination of two or more types. However, since it may take time for power generation to start (for the temperature of the structural members to rise) as described above, it is preferable to use a combination of elements that can generate power through initial vibration.

[0059] <Communication System> The measurement method of the present invention preferably uses a communication system that transmits data on the calorific value of structural members to the outside. By using a communication system that transmits data on the calorific value of structural members to the outside, the calorific value data of structural members can be confirmed even from a location far from the building, making it easier to measure the degree of damage to the building caused by an earthquake. When a communication system is used, a receiver is generally used to receive the transmitted calorific value data.

[0060] Examples of the communication system include wired communication systems such as optical fiber and wired LAN, and wireless communication systems such as wireless USB, MBOA, Bluetooth, UWB, ZigBee, Twilite, and LPWA. As the communication system, a wireless communication system is preferred because it can more easily measure the degree of damage to buildings caused by an earthquake.

[0061] <Control Device> In the measurement method of the present invention, various operations can be performed manually or automatically using a control device equipped with a control circuit. As the control circuit, for example, a conventionally known device such as a computer that may be equipped with a CPU (Central Processing Unit), a memory, etc., or a microcomputer (so-called microcomputer) can be used.

[0062] (Measuring system for earthquake damage to buildings) Measurement of earthquake damage to buildings using the measurement method of the present invention described above can be performed using a measuring system for earthquake damage to buildings of the present invention (hereinafter simply referred to as the "measurement system").

[0063] As shown in FIG. 5 , the earthquake damage measurement system 20 of the present invention includes a measurement unit 21 that acquires heat quantity data from structural components constituting the structure, and a calculation unit 22 that calculates the degree of damage to the structure based on the heat quantity. Such a measurement system allows for accurate and easy measurement of the degree of earthquake damage to the structure. As shown in FIG. 6 , the measurement system 20 of the present invention may optionally further include a communication unit 23 that includes a communication system that transmits the heat quantity data acquired by the measurement unit 21 to an external device, and a control unit 24 that includes a control device that automatically controls various operations using a control circuit. As shown in FIG. 6 , the measurement system 20 of the present invention may include both the communication unit 23 and the control unit 24, or may include only one of the communication unit 23 and the control unit 24. Although not shown, the measurement system 20 generally includes a power source for operating the measurement unit 21, the communication unit 23, the control unit 24, and, in some cases, the calculation unit 22.

[0064] <Measurement Unit> The measurement unit acquires data on the heat quantity of the structural members that make up the building. Here, the structural members may be any of those mentioned above.

[0065] It is preferable to determine the heat quantity of a structural member from temperature change. If the heat quantity is determined from the temperature change of a structural member, the degree of damage to a building caused by an earthquake can be measured more accurately. Furthermore, because temperature is easy to measure, the degree of damage to a building caused by an earthquake can be measured more simply. Note that the heat quantity of a structural member can also be determined from, in addition to temperature change, the amount of power generated by a thermoelectric conversion element, for example.

[0066] The measuring unit preferably acquires data on the amount of plastic heat generated by the structural members constituting the building and data on the amount of heat generated by the thermoelastic effect. By acquiring the amount of plastic heat generated and the amount of heat generated by the thermoelastic effect, the calculating unit (described later) can calculate the cumulative plastic strain and the number of elastic vibrations of the structural members.

[0067] The measurement unit preferably includes a temperature sensor. If the measurement unit includes a temperature sensor, the heat quantity of the structural member can be determined by the temperature sensor. The measurement unit more preferably includes a temperature sensor installed on the structural member, and even more preferably, the heat quantity is determined by a temperature sensor installed on the surface of the structural member. Here, the temperature sensor described above can be used as appropriate. Note that, when the measurement unit includes a temperature sensor, the measurement system of the present invention generally includes a detector that detects the electrical output value of the temperature sensor, and a power source for operating the temperature sensor and the detector.

[0068] When the measurement unit includes a temperature sensor, it is preferable that the measurement unit further includes other sensors. By including other sensors, the degree of damage to the structure caused by the earthquake can be measured with even greater accuracy. Here, the other sensors may be any of those described above.

[0069] <Calculation Unit> The calculation unit calculates the degree of damage to the building based on the heat quantity of the structural members.

[0070] The degree of damage to a building is preferably determined using the cumulative plastic strain of a structural member calculated from the amount of plastic heat generated and the number of elastic vibrations calculated from the amount of heat generated by the thermoelastic effect. If the degree of damage to a building is determined using the cumulative plastic strain and the number of elastic vibrations, the degree of damage to a building caused by an earthquake can be measured more accurately. Furthermore, it is preferable to further use the plastic strain amplitude for each half cycle of the elastic vibration of the structural member to determine the degree of damage. If the degree of damage is further determined using the plastic strain amplitude, the degree of damage to a building caused by an earthquake can be measured even more accurately. The cumulative plastic strain, the number of elastic vibrations, and the plastic strain amplitude can be determined using the methods described above.

[0071] <Communication Unit> The communication unit includes a communication system that transmits the calorific value data acquired by the measurement unit to an external device. The communication system may be any of those described above. The communication unit generally includes a receiver that receives the transmitted calorific value data.

[0072] <Controller> The controller includes a control device that automatically controls various operations using a control circuit. As the control circuit, the above-mentioned devices can be used as appropriate.

[0073] <Power Supply> As the power supply, the above-mentioned power supplies can be used appropriately.

[0074] The present invention will be specifically explained below based on test examples, but the present invention is not limited to these test examples.

[0075] Test Example 1 Preparation of Test Specimen A steel material (SS400) was cut out to prepare a test specimen 30 having a length of 20 cm (longitudinal direction in FIG. 7 ), a width of 10 cm (horizontal direction in FIG. 7 ), and a cross section of 20 mm square (not shown), as shown in FIG. 7 .

[0076] <Vibration Test> Next, a vibration test was performed on the test specimen 30. Specifically, the test specimen 30 was attached to a tension-compression high-speed fatigue testing machine (manufactured by MTS Systems Corporation, product name: Axial / Torsional Test System Model 319.25), and as shown in FIG. 7 , a force F (left side of FIG. 7 ) from the outside of the test specimen 30 and a force F (right side of FIG. 7 ) from the inside of the test specimen 30 were alternately and continuously applied to deform (displace) the test specimen 30 and vibrate it. The vibration test was performed under the following conditions: a displacement of ±22.2 mm, a frequency of 3 Hz, and 900 vibrations (approximately 5 minutes) at room temperature (25°C). The temperature change at point P of the test specimen 30 during this vibration was measured using a sensor. Other details of the vibration test are described below. [Details] Sensor: Metal thermocouple Power supply: Battery Control circuit: General low-power microcomputer Communication system: Bluetooth Low Energy Receiver: PC with built-in Bluetooth receiver function

[0077] <Test Results> Immediately after the start of vibration, a temperature rise in the test specimen 30 was confirmed using a metal thermocouple. In addition to the gradual temperature rise, minute, periodic temperature changes were also observed. The temperature at point P of the test specimen 30 finally reached 100°C. The amount of plastic heat generated was calculated from the measured temperature values, and the cumulative plastic strain was calculated from this amount of plastic heat generated. This was approximately equal to the cumulative plastic strain calculated from the displacement. Furthermore, the amount of heat generated by the thermoelastic effect was calculated from the measured temperature values. The number of elastic vibrations was calculated from this amount of heat generated by the thermoelastic effect. This was equal to the number of vibrations. The temperature data measured above was transmitted via a communication system and could be received by a PC 10 m away.

[0078] (Test Example 2) The operation and test were performed in the same manner as in Test Example 1, except that a CNT thermoelectric conversion element (SGCNT was used as the semiconductor) manufactured to fit the shape of the test specimen was used instead of a metal thermocouple as a sensor, and vibration tests were performed at both frequencies of 3 Hz and 10 Hz. The CNT thermoelectric conversion element used was a 1 mm thick sheet-like element with a performance of Voc: 0.6 V and Isc: 0.5 mA at a temperature difference between 120 ° C and 25 ° C. Here, the power generated by the CNT thermoelectric conversion element was also used as a power source using a boost converter that converted the output to 3 V.

[0079] <Test Results> As in Test Example 1, a gradual temperature rise and minute, periodic temperature changes were observed. As in Test Example 1, the cumulative plastic strain calculated from the measured temperature values ​​was nearly equal to the cumulative plastic strain calculated from the displacement. Furthermore, the number of elastic vibrations calculated from the measured temperature values ​​was the same as the number of vibrations. Furthermore, once the temperature exceeded 60°C, temperature measurement became possible using only the power generated by the CNT thermoelectric conversion element. This means that the CNT thermoelectric conversion element functioned as both a temperature sensor and a power source. Furthermore, at both frequencies of 3 Hz and 10 Hz, the CNT thermoelectric conversion element was not damaged during measurement, and accurate temperature measurement was possible until the end.

[0080] Test Example 3 The operation and test were carried out in the same manner as in Test Example 2, except that a general inorganic thermoelectric element was used instead of the CNT thermoelectric conversion element as the sensor. The inorganic thermoelectric element used was a 2 cm square plate (thickness 0.5 mm) with a performance of Voc: 0.1 V and Isc: 5 mA at a temperature difference between 120°C and 25°C. As in Test Example 2, the power generated by the inorganic thermoelectric element was also used as a power source using a boost converter that converted the output to 3 V.

[0081] <Test Results> After approximately 180 seconds from the start of measurement at a frequency of 3 Hz and approximately 80 seconds at a frequency of 10 Hz, the inorganic thermoelectric element broke, making temperature measurement impossible. However, until the breakage, a gradual temperature rise and minute, periodic temperature changes were observed, as in Test Example 2. As in Test Example 2, the cumulative plastic strain was calculated from the measured temperature values ​​and was nearly equal to the cumulative plastic strain calculated from the above-mentioned displacement. Furthermore, the number of elastic vibrations was calculated from the measured temperature values ​​and was the same as the number of vibrations. Furthermore, as in Test Example 2, once the temperature exceeded 60°C, it became possible to measure the temperature using power generation by the inorganic thermoelectric element alone.

[0082] (Test Example 4) <Preparation of Test Structure> As shown in FIG. 8 , a test structure 40 was prepared, which consisted of a steel frame 41, a test specimen 42 positioned between the steel frames 41 arranged at an angle, and a metal thermocouple 43 installed in the test specimen 42.

[0083] <Vibration Test> A vibration test was conducted using the test structure 40 shown in Figure 8. The vibration test was conducted using an externally attached dynamic jack under the conditions of a displacement of ±22.2 mm, a frequency of 3 Hz, and a vibration count of 900 times (for approximately 5 minutes). Other operations and tests were conducted in the same manner as in Test Example 1. The dynamic jack used was a "Portable Hydraulic Vibrator Force Simulator EHF-JF20kNV-100-A10" manufactured by Shimadzu Corporation.

[0084] <Test Results> As in Test Example 1, a gradual temperature rise and minute, periodic temperature changes were observed. As in Test Example 1, the cumulative plastic strain calculated from the temperature measurements was approximately equal to the cumulative plastic strain calculated from the displacement. Furthermore, the elastic vibration frequency calculated from the temperature measurements was equal to the vibration frequency.

[0085] Test Example 5 <Preparation of Test Structure> As shown in FIG. 9, a test structure 40 was prepared, which was made up of a steel frame 41 and metal thermocouples 43 installed at the corners of the steel frame 41 .

[0086] <Vibration Test> A vibration test was carried out in the same manner as in Test Example 4 using the test structure 40 shown in FIG.

[0087] <Test Results> Although not as clear as in Test Example 4, a gradual temperature rise and minute, periodic temperature changes were confirmed. As in Test Example 4, the cumulative plastic strain calculated from the temperature measurements was nearly equal to the cumulative plastic strain calculated from the displacement. Furthermore, the number of elastic vibrations calculated from the temperature measurements was the same as the number of vibrations.

[0088] Comparative Test Example 1 The same operation and test as in Test Example 1 were carried out, except that a strain gauge was used instead of the metal thermocouple as the sensor.

[0089] <Test Results> Although the number of elastic vibrations could be determined from the strain gauge measurements, it was not possible to determine the cumulative plastic strain.

[0090] According to the present invention, it is possible to provide a measurement method that can easily and accurately measure the degree of damage to a structure caused by an earthquake. Also, according to the present invention, it is possible to provide a measurement system that can easily and accurately measure the degree of damage to a structure caused by an earthquake.

[0091] 10: Building structure 11: Foundation 12: Pillar 13: Beam 14: Brace 15: Damper 16: Temperature sensor 20: Measurement system 21: Measurement unit 22: Calculation unit 23: Communication unit 24: Control unit 30: Test specimen 40: Test building structure 41: Steel frame 42: Test specimen 43: Metal thermocouple

Claims

1. A method for measuring damage to a structure due to an earthquake, comprising: A measurement method for determining the degree of damage to a building based on the heat quantity of structural components that make up the building.

2. the heat quantity includes a plastic heat quantity and a heat quantity due to a thermoelastic effect, 2. The measurement method according to claim 1, wherein the degree of damage is determined using the cumulative plastic strain of the structural member determined from the amount of plastic heat generated and the number of elastic vibrations determined from the amount of heat generated by the thermoelastic effect.

3. The measurement method according to claim 1 , wherein the heat quantity is determined from a temperature change of the structural member.

4. The measurement method according to claim 1 , wherein the structural member is a damper.

5. The measurement method according to claim 1 , wherein the heat quantity is determined by a temperature sensor installed in the structural member.

6. The measurement method according to claim 5 , wherein the temperature sensor is activated by energy from the earthquake.

7. The measuring method according to claim 5 , wherein the temperature sensor is a thermoelectric conversion element.

8. The measuring method according to claim 7 , wherein the thermoelectric conversion element is flexible.

9. The measurement method according to claim 7 , wherein the thermoelectric conversion element comprises a semiconductor containing carbon nanotubes.

10. The measurement method according to claim 9 , wherein the carbon nanotubes include single-walled carbon nanotubes.

11. The measurement method according to claim 5 , further comprising the step of using a sensor different from the temperature sensor.

12. The measurement method according to any one of claims 1 to 11, wherein a communication system is used to transmit the heat quantity data to an external device.

13. The measurement method according to claim 12 , wherein the communication system is a wireless communication system.

14. A system for measuring damage to structures due to earthquakes, comprising: A measurement unit that acquires data on the heat quantity of structural members that constitute the building; A calculation unit that calculates the degree of damage to the structure based on the heat quantity; A measurement system comprising: