WO2023190394A1

WO2023190394A1 - Method and system for measuring damage of building caused by earthquake

Info

Publication number: WO2023190394A1
Application number: PCT/JP2023/012306
Authority: WO
Inventors: 秀樹内田; 貴博山本; 拓海伊藤; 健士郎森; 宇史中嶋; 洋一郎橋爪; 昌廣元祐
Original assignee: 日本ゼオン株式会社; 学校法人東京理科大学
Priority date: 2022-03-31
Filing date: 2023-03-27
Publication date: 2023-10-05

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

Method and system for measuring damage to buildings due to earthquakes

The present invention relates to a method for measuring damage to buildings due to an earthquake, and a system for measuring damage to buildings due to an earthquake.

Sensors are installed on the structural members that make up construction and civil engineering structures (hereinafter also referred to as "buildings"), and based on the information from these sensors, the extent of damage to buildings due to earthquakes can be ascertained, and Structural health monitoring, which detects damage and assesses structural integrity, is attracting attention.
For example, Patent Document 1 proposes an estimation system and estimation method for estimating the damage status of buildings due to earthquakes using physical sensors such as acceleration sensors and strain gauges.

JP2020-128951A

Here, in the conventional method using an acceleration sensor, even if the acceleration sensor is installed on a structural member, vibrations other than the vibration of the structural member itself (for example, vibrations of other structural members around the structural member) (vibration, etc.) will also be reflected in the measurement. Therefore, methods using acceleration sensors need to measure damage to buildings by taking into account vibrations other than the vibrations of the structural members themselves, but calculations using simulations are required each time measurement is performed, and as a result, analysis The problem was that it became complicated.
Furthermore, the method using strain gauges has a problem in that the accuracy of measuring damage to buildings is low.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a measurement method that can accurately and easily measure the degree of damage to buildings caused by earthquakes.
Another object of the present invention is to provide a measurement system that can accurately and easily measure the degree of damage to buildings caused by earthquakes.

The present inventors have newly discovered that the above problem can be solved by determining the degree of damage to a building based on the amount of heat of the structural members that make up the building, and have completed the present invention.

That is, the present invention aims to advantageously solve the above-mentioned problems.[1] The present invention provides a method for measuring damage to a building due to an earthquake, which This is a measurement method that determines the degree of damage to the building based on the amount of heat. With such a measurement method, the extent of damage to buildings caused by earthquakes can be easily and accurately measured.

[2] In the measurement method of [1] above, the amount of heat includes the amount of plastic heat generation and the amount of heat due to thermoelastic effect, and the degree of damage is determined by the cumulative plastic strain of the structural member determined from the amount of plastic heat generation. and the number of elastic vibrations determined from the amount of heat due to 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 a building caused by an earthquake can be measured with higher accuracy.

[3] In the measuring method of [1] or [2] above, it is preferable that the amount of heat is determined from a temperature change of the structural member.
If the amount of heat is determined from temperature changes in structural members, the extent of damage to buildings caused by earthquakes can be measured with greater accuracy. Furthermore, since temperature is easy to measure, the extent of damage to buildings caused by earthquakes can be measured more easily.

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

[5] In the measurement method of any one of [1] to [4] above, it is preferable that the amount of heat is determined by a temperature sensor installed on the structural member.
If the amount of heat is determined using temperature sensors installed in structural members, the extent of damage to buildings caused by earthquakes can be measured more accurately and easily. Furthermore, since the temperature sensor can measure temperature in a short time, power consumption can be reduced.

[6] In the measurement method of [5] above, it is preferable that the temperature sensor is operated by energy of the earthquake.
If temperature sensors are powered by earthquake energy, electricity usage can be reduced.

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

[8] In the measurement method of [7] above, it is preferable that the thermoelectric conversion element has flexibility.
If the thermoelectric conversion element has flexibility, the risk of measurement being impossible due to vibration of structural members can be reduced, and measurement can be performed over a long period of time.

[9] In the measurement method of [7] or [8] above, the thermoelectric conversion element preferably includes a semiconductor containing carbon nanotubes.
If the thermoelectric conversion element includes a semiconductor containing carbon nanotubes, the degree of damage to buildings caused by earthquakes can be measured with even greater accuracy. Furthermore, if the thermoelectric conversion element includes a semiconductor containing carbon nanotubes, it is possible to reduce the risk of making measurements impossible due to vibrations of structural members, and it becomes possible to carry out measurements over a long period of time.

[10] In the measuring method of [9] above, it is preferable that the carbon nanotubes include single-walled carbon nanotubes.
If the carbon nanotubes include single-walled carbon nanotubes, the extent of damage to buildings caused by earthquakes can be measured with even greater accuracy.

[11] It is preferable that the measurement method of any one of [5] to [10] above further uses a sensor different from the temperature sensor.
If a sensor different from the temperature sensor is further used, the extent of damage to buildings caused by earthquakes can be measured with even greater precision.

[12] It is preferable that the measuring method of any one of the above [1] to [11] uses a communication system that transmits the data of the amount of heat to the outside.
By using a communication system that transmits heat value data to the outside world, it is possible to more easily measure the extent of damage to buildings caused by earthquakes.

[13] In the measuring method of [12] above, it is preferable that the communication system is a wireless communication system.
If the communication system is a wireless communication system, the degree of damage to buildings caused by an earthquake can be measured more easily.

[14] The present invention also provides a system for measuring damage to a building caused by an earthquake, which measures structural members constituting the building. This is a measurement system comprising: a measurement section that acquires data on the amount of heat; and a calculation section that calculates the degree of damage to the building based on the amount of heat. With such a measurement system, the extent of damage to buildings caused by earthquakes can be easily and accurately measured.

[15] In the measurement system according to [14] above, the amount of heat includes a plastic calorific value and a calorific value due to a thermoelastic effect, and the degree of damage is determined by the cumulative plastic strain of the structural member determined from the plastic calorific value. and the number of elastic vibrations determined from the amount of heat due to 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 a building caused by an earthquake can be measured with higher accuracy.

[16] In the measurement system of [14] or [15] above, it is preferable that the amount of heat is determined from a temperature change of the structural member.
If the amount of heat is determined from temperature changes in structural members, the extent of damage to buildings caused by earthquakes can be measured with greater precision. Furthermore, since temperature is easy to measure, the extent of damage to buildings caused by earthquakes can be measured more easily.

[17] In the measurement system according to 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 a building caused by an earthquake can be measured with higher accuracy.

[18] In the measurement system according to any one of [14] to [17] above, the measurement section preferably includes a temperature sensor installed on the structural member.
If the measurement unit includes a temperature sensor installed on a structural member, the degree of damage to a building caused by an earthquake can be easily measured with higher accuracy. Furthermore, since the temperature sensor can measure temperature in a short time, power consumption can be reduced.

[19] In the measurement system of [18] above, it is preferable that the temperature sensor is operated by energy of the earthquake.
If temperature sensors are powered by earthquake energy, electricity usage can be reduced.

[20] In the measurement system of [18] or [19] above, it is preferable that the temperature sensor is a thermoelectric conversion element.
If the temperature sensor is a thermoelectric conversion element, the degree of damage to buildings caused by earthquakes can be measured with even greater precision. Furthermore, if the temperature sensor is a thermoelectric conversion element, it can also be used as a power source.

[21] In the measurement system of [20] above, it is preferable that the thermoelectric conversion element has flexibility.
If the thermoelectric conversion element has flexibility, the risk of measurement being impossible due to vibration of structural members can be reduced, and measurement can be performed over a long period of time.

[22] In the measurement system of [20] or [21] above, it is preferable that the thermoelectric conversion element includes a semiconductor containing carbon nanotubes.
If the thermoelectric conversion element includes a semiconductor containing carbon nanotubes, the degree of damage to buildings caused by earthquakes can be measured with even greater accuracy. Furthermore, if the thermoelectric conversion element includes a semiconductor containing carbon nanotubes, it is possible to reduce the risk of making measurements impossible due to vibrations of structural members, and it becomes possible to carry out measurements over a long period of time.

[23] In the measurement system of [22] above, it is preferable that the carbon nanotubes include single-walled carbon nanotubes.
If the carbon nanotubes include single-walled carbon nanotubes, the extent of damage to buildings caused by earthquakes can be measured with even greater precision.

[24] In the measurement system according to any one of [18] to [23] above, it is preferable that the measurement section 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 building caused by the earthquake can be measured with even greater precision.

[25] Preferably, the measurement system according to any one of [14] to [24] above further includes a communication section including a communication system that transmits the data on the amount of heat to the outside.
If the device further includes a communication section that includes a communication system that transmits data on the amount of heat to the outside, the degree of damage to buildings caused by earthquakes can be measured more easily.

[26] In the measurement system of [25] above, it is preferable that the communication system is a wireless communication system.
If the communication system is a wireless communication system, the degree of damage to buildings caused by an earthquake can be measured more easily.

According to the present invention, it is possible to provide a measurement method that can accurately and easily measure the degree of damage to buildings caused by earthquakes.
Further, according to the present invention, it is possible to provide a measurement system that can accurately and easily measure the degree of damage to buildings caused by earthquakes.

This is an example of a graph schematically showing temperature changes in structural members during an earthquake. This is an enlarged graph of the initial stage of the earthquake occurrence of the graph shown in FIG. 1. 3 is a graph schematically showing a temperature change in the graph shown in FIG. 2 separated into a temperature change due to plastic calorific value and a temperature change due to heat of thermoelastic effect. It is a schematic diagram showing an example of a building provided with a damper in which a temperature sensor was installed. FIG. 1 is a block diagram showing an example of a measurement system of the present invention. FIG. 1 is a block diagram showing an example of a measurement system of the present invention. 2 is a schematic diagram for explaining the test method of Test Example 1. FIG. FIG. 4 is a schematic diagram for explaining the test method of Test Example 4. FIG. 6 is a schematic diagram for explaining the test method of Test Example 5.

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

(Method for measuring damage to buildings due to earthquake)
The method for measuring damage to a building due to an earthquake (hereinafter also simply referred to as "measuring method") of the present invention determines the degree of damage to the building based on the amount of heat of the structural members that make up the building. With such a measurement method, the extent of damage to buildings caused by earthquakes can be easily and accurately measured. The reason for this is thought to be that there is a correlation between the degree of damage to the building and the strain on the structural members, and a correlation between the strain on the structural members and the amount of heat. be done. In other words, since there is a correlation between the degree of damage to the building, the strain in the structural members, and the amount of heat in the structural members, based on the change in the amount of heat in the structural members due to vibrations caused by an earthquake, This allows us to determine the extent of damage to buildings. The amount of heat in a structural member can be determined with high accuracy because it is not easily affected by surrounding members or the environment, and it is also easy to determine, so this amount of heat can be used to determine the degree of damage. If used for this purpose, it will be possible to easily and accurately measure the extent of damage to buildings caused by earthquakes.

In the measurement method of the present invention, the amount of heat of the structural member is not particularly limited as long as it is a calculation method that can determine the amount of heat or a measurement method that can measure the amount of heat, but it is preferably determined from the temperature change of the structural member. If the amount of heat is determined from temperature changes in structural members, the extent of damage to buildings caused by earthquakes can be measured with greater precision. Furthermore, since temperature is easy to measure, the extent of damage to buildings caused by earthquakes can be measured more easily.

In the measurement method of the present invention, the amount of heat in the structural member includes the amount of plastic heat generated and the amount of heat due to the thermoelastic effect, and the degree of damage is determined by the cumulative plastic strain of the structural member determined from the amount of plastic heat generated and the amount of heat due to the thermoelastic effect. It is preferable to calculate it using the number of elastic vibrations calculated from the amount of heat. If the degree of damage 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 and easily. Specifically, the magnitude of the recent earthquake and the extent of damage to buildings (structural members) can be evaluated from the plastic calorific value (cumulative plastic strain), and the calorific value due to thermoelastic effects (number of elastic vibrations) can be used to evaluate Because it is possible to predict damage to buildings (structural members) due to future earthquakes (for example, how many more earthquakes with a seismic intensity of 5 or higher will occur and/or how many seconds will it take for a building to collapse?), It is possible to measure the extent of damage to buildings with higher accuracy.

Hereinafter, an example of a method for determining the cumulative plastic strain and the number of elastic vibrations will be described with reference to FIGS. 1 to 3 when determining the amount of heat based on the temperature change of a component.
Here, FIG. 1 is an example of a graph schematically showing temperature changes of structural members during an earthquake, FIG. 2 is an enlarged graph of the initial stage of the earthquake occurrence of the graph shown in FIG. 1, and FIG. 3 is a graph schematically showing a temperature change in the graph shown in FIG. 2 separated into a temperature change due to plastic calorific value and a temperature change due to heat of thermoelastic effect.

As shown in Figure 1, the temperature of structural members during an earthquake increases while repeating small and periodic temperature changes (see also Figure 2), and when the earthquake stops (i.e., the temperature of the structural members increases). Once the member stops vibrating), the temperature returns to the temperature at which the earthquake occurred (usually room temperature). Here, as shown in FIG. 3, the temperature change A (temperature rise) of the structural member includes a temperature change B caused by the plastic calorific value of the structural member, and a temperature change caused by the heat amount of the thermoelastic effect of the structural member. Contains C.
As mentioned above, since there is a correlation between the strain of the structural member and the amount of heat, it can be said that there is also a correlation between the cumulative plastic strain of the structural member and the amount of plastic heat generated by the structural member. Therefore, the plastic calorific value of the structural member can be determined from the temperature change B, and the cumulative plastic strain of the structural member can be determined from this plastic calorific value.
On the other hand, since the temperature change C is caused by the amount of heat of the thermoelastic effect of the structural member, that is, the compression (contraction) and tension (expansion) of the structural member, the number of cycles of the temperature change C is integrated. By doing so, the number of elastic vibrations of the structural member can be determined.
Note that the temperature change B can be determined by calculating the average value for each cycle of the temperature change A and connecting these values with a straight line. Further, the temperature change C can be determined from the difference between the temperature change A and the temperature change B ("temperature change A" - "temperature change B").
Here, the cumulative plastic strain of a structural member can be calculated by, for example, determining the amount of energy absorbed (plastic calorific value) from the temperature change B (temperature rise) of the structural member by inverse analysis of the heat conduction analysis. It can be determined by appropriately using restoring force characteristics and cross-sectional flatness maintenance. Further, the number of elastic vibrations of the structural member can be specifically determined, for example, from the number of cycles of temperature change C until the temperature of the structural member stops increasing (in other words, until the temperature of the structural member starts to decrease). .

In order to determine the degree of damage, it is further preferable to use the plastic strain amplitude for each half cycle of elastic vibration of the structural member. If the degree of damage is further determined using the plastic strain amplitude, the degree of damage to buildings caused by earthquakes can be measured with even greater precision.
Note that the plastic strain amplitude for each half cycle can be obtained by calculating each half cycle time from the cycle of elastic vibration and dividing the cumulative plastic strain by the half cycle time.

Here, in the above, the amount of heat was determined from the temperature change, but in addition to the temperature change, the amount of heat of the structural member can also be determined from the amount of power generated by a thermoelectric conversion element, etc., which will be described later.

<Structural members>
In the measurement method of the present invention, the structural member is not particularly limited as long as it constitutes a building, and examples thereof include columns, beams, braces, walls, roofs, foundations, etc. of the building. Structural members also include dampers provided in the middle of braces, etc., and seismic isolation members such as supports (isolators) provided under columns and foundations. Here, a damper is a component that prevents damage to columns, beams, braces, etc. by absorbing energy such as earthquake shock and vibration, and includes viscoelastic dampers, elastoplastic dampers (hysteresis dampers), etc. .
Among the above-mentioned structural members, dampers are preferable, and elastoplastic dampers are more preferable, since the degree of damage to buildings caused by earthquakes can be measured with higher accuracy.

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, and wood. Among these, metal is preferable, and steel is more preferable, since the degree of damage to buildings caused by earthquakes can be measured with higher accuracy.

<Temperature sensor>
In the measuring method of the present invention, it is preferable that the amount of heat of the structural member is determined using a temperature sensor. Since a temperature sensor can measure temperature in a short time, using a temperature sensor can reduce power consumption.
Moreover, it is more preferable that the amount of heat of the structural member is determined by a temperature sensor installed in the structural member. If the amount of heat in 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.
Furthermore, it is more preferable that the amount of heat of the structural member is determined by a temperature sensor installed on the surface of the structural member. If the amount of heat in 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 with even greater accuracy. Furthermore, since a temperature sensor can be easily installed on the surface of a structural member, it is possible to more easily measure the degree of damage to a building caused by an earthquake.
Note that when a temperature sensor is used, a detector for detecting the electrical output of the temperature sensor and a power source for operating the temperature sensor and the detector are generally used.

Hereinafter, when the structural member is a damper, an example of the installation location of the temperature sensor will be described with reference to FIG. 4.
Here, FIG. 4 is a schematic diagram showing an example of a building including a damper in which a temperature sensor is installed. As shown in FIG. 4, the building 10 includes a foundation 11, a pillar 12 located on the foundation 11, a beam 13 lying on the pillar 12, and a brace provided diagonally between the two pillars 12. 14. A damper 15 is provided in the middle of the brace 14, and a temperature sensor 16 is provided on the damper 15.

It is preferable that the temperature sensor is operated by earthquake energy, since it can reduce the amount of electricity used. Note that the energy caused by an earthquake includes not only vibrations but also various energies such as heat generated by vibrations.

The temperature sensor is not particularly limited as long as it can measure temperature, but for example, contact type such as thermoelectric conversion element, integrated circuit temperature sensor (IC temperature sensor), thermistor, resistance temperature detector (RTD), metal thermocouple, etc. Examples include non-contact temperature sensors such as temperature sensors and infrared thermometers. Among these, contact temperature sensors are preferred, and thermoelectric conversion elements or metal thermocouples are more preferred, since they can measure the degree of damage to buildings due to earthquakes with higher accuracy. Furthermore, thermoelectric conversion elements are particularly preferred since they can also be used as power sources. Note that when the thermoelectric conversion element is also used as a power source, it may be converted to a voltage suitable for the power source using a step-up converter or the like.
Here, the thermoelectric conversion element is a thermoelectric element using a combination of a p-type semiconductor and an n-type semiconductor, such as bismuth-tellurium (Bi-Te), lead-tellurium (Pb-Te) , those comprising a semiconductor containing an inorganic material such as silicon germanium (Si--Ge) (hereinafter also referred to as "inorganic thermoelectric conversion element"). In addition, the thermoelectric conversion element includes a semiconductor (p-type semiconductor and/or n-type semiconductor) containing carbon nanotubes (hereinafter also referred to as "CNT") (hereinafter also referred to as "CNT thermoelectric conversion element"). You can also use
The temperature sensors listed above may be used alone or in combination of two or more.

It is preferable that the thermoelectric conversion element has flexibility. If the thermoelectric conversion element has flexibility, the durability of the thermoelectric conversion element can be improved. That is, it is possible to reduce the risk of making measurement impossible due to vibrations of structural members, and it is possible to carry out measurements over a long period of time.

The thermoelectric conversion element is preferably a CNT thermoelectric conversion element. If the thermoelectric conversion element is a CNT thermoelectric conversion element, it is possible to measure the degree of damage to a building due to an earthquake with higher accuracy. Furthermore, since CNT thermoelectric conversion elements have excellent flexibility, by using CNT thermoelectric conversion elements, it is possible to reduce the risk of making measurements impossible due to vibrations of structural members, and it is possible to carry out measurements over a long period of time.
Here, carbon nanotubes have a structure in which a graphene sheet is wound into a cylindrical shape, and are roughly classified into single-walled CNTs and multi-walled CNTs based on the number of constituent walls of the carbon nanotubes.

Preferably, the temperature sensor is sheet-shaped. If the temperature sensor is in the form of a sheet, it is possible to reduce the risk of damage to the temperature sensor due to vibrations of structural members and make measurement impossible, and it is possible to carry out measurements over a long period of time.
When the temperature sensor is in the form of a sheet, 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 that measurement will become impossible due to damage to the temperature sensor due to vibration of the structural member can be further reduced, and measurement can be performed over a longer period of time. Note that the thickness of the sheet-like temperature sensor is, for example, 0.1 mm or more, and may be 0.5 mm or more.

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. Single-walled CNTs tend to have better thermoelectric properties (Seebeck coefficient) than multi-walled CNTs, so they can generate a higher electromotive force (voltage) due to temperature changes caused by shaking, and as a result, buildings are less susceptible to earthquakes. This is because the degree of damage can be measured with even greater precision.
Single-walled CNTs are produced by supplying a raw material compound and a carrier gas onto a base material having a catalyst layer for CNT production on the surface, and synthesizing CNTs by chemical vapor deposition (CVD). , manufactured according to the method (super growth method; see International Publication No. 2006/011655) in which the catalytic activity of the catalyst layer is dramatically improved by the presence of a small amount of oxidizing agent (catalyst activating material) in the system. (Hereinafter, CNTs produced according to such a method may be referred to as "SGCNTs"). SGCNTs tend to have higher Seebeck coefficients than other CNTs. Therefore, if the CNTs include SGCNTs, it is possible to generate a higher electromotive force (voltage) due to temperature changes due to shaking, and as a result, the degree of damage to buildings caused by earthquakes can be measured with particularly high accuracy.

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

The BET specific surface area of the CNT is preferably 600 m ² /g or more, more preferably 800 m ² /g or more, and even more preferably 1000 m ² /g or more.
If the BET specific surface area of CNT is equal to or larger than the above lower limit, the bending resistance of the CNT thermoelectric conversion element can be improved. Note that the BET specific surface area of CNT is, for example, 2600 m ² /g or less, and may be 2000 m ² /g or less. Note that the BET specific surface area of CNT is the nitrogen adsorption specific surface area measured using the BET method.

In the CNT, the ratio of the G band peak intensity to the D band peak intensity (G/D ratio) in the Raman spectrum is preferably 0.5 or more, and preferably 5.0 or less.

<Other sensors>
When using a temperature sensor in the measurement method of the present invention, it is preferable to further use a sensor different from the temperature sensor (hereinafter also referred to as "other sensor"). If other sensors are used, the extent of damage to buildings caused by earthquakes can be measured with even greater accuracy.
Examples of other sensors include strain gauges, vibration sensors, speed sensors, acceleration sensors, and audio sensors. Among these, strain gauges are preferred because they have excellent accuracy in measuring the number of elastic vibrations.
The other sensors mentioned above may be used alone or in combination of two or more.

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

<Power source>
The power source used to operate the temperature sensor is not particularly limited, but includes, for example, batteries such as primary batteries and secondary batteries; grid power supplied from a commercial power distribution network; power sources using natural energy, etc. It will be done. Here, power sources using natural energy include, for example, photovoltaic elements that use light energy such as sunlight, vibration power generation elements that use vibrational energy such as earthquakes, and thermoelectric conversion elements that use thermal energy such as earthquakes. etc. Among these, vibration power generation elements and thermoelectric conversion elements are preferred because they can efficiently use the energy generated by earthquakes. A thermoelectric conversion element is particularly preferable because it can function as both the temperature sensor and the power source, that is, it can measure the temperature of the structural member while also generating electricity and functioning as a power source.
Note that if only a thermoelectric exchange element is used as a power source, it may not be possible to measure the temperature of the structural member until power generation starts (until the temperature of the structural member rises); By predicting the changes measured before power generation begins, it is possible to measure the extent of damage to buildings during the entire earthquake.
The power sources listed above may be used alone or in combination of two or more, but as mentioned above, it takes time until power generation starts (until the temperature of the structural members rises). Therefore, it is preferable to use a combination of elements that can generate electricity through initial vibration.

<Communication system>
The measurement method of the present invention preferably uses a communication system that transmits data on the amount of heat of the structural member to the outside. By using a communication system that transmits data on the heat content of structural members to the outside, data on the heat content of structural members can be checked even at a location far from the building, making it easier to measure the extent of damage to buildings caused by earthquakes. can.
Note that when using a communication system, a receiver is generally used to receive transmitted data on the amount of heat.

Examples of communication systems 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 preferable because it can more easily measure the degree of damage to buildings caused by an earthquake.

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

(Measurement system for damage to buildings due to earthquakes)
Measurement of damage to buildings due to an earthquake using the measurement method of the present invention described above can be performed using the system for measuring damage to buildings due to an earthquake (hereinafter also simply referred to as "measurement system") of the present invention. .

As shown in FIG. 5, the system 20 for measuring damage to buildings due to earthquakes according to the present invention includes a measurement unit 21 that acquires data on the amount of heat of structural members constituting the building, and a measurement unit 21 that acquires data on the amount of heat of structural members constituting the building. and a calculation unit 22 that calculates the degree of. With such a measurement system, the extent of damage to buildings caused by earthquakes can be easily and accurately measured.
Furthermore, as shown in FIG. 6, the measurement system 20 of the present invention includes a communication section 23 optionally equipped with a communication system for transmitting heat amount data acquired by the measurement section 21 to the outside, and a control circuit to automatically perform various operations. The control unit 24 may further include a control unit 24 that is operated by a control device. Note that, as shown in FIG. 6, the measurement system 20 of the present invention may include both the communication section 23 and the control section 24, or may include either one of the communication section 23 and the control section 24. .
Although not shown, the measurement system 20 generally includes a power source for operating the measurement section 21, the communication section 23, the control section 24, and possibly the calculation section 22.

<Measurement part>
The measurement unit acquires data on the amount of heat of the structural members that make up the building.
Here, as the structural members, those mentioned above can be used as appropriate.

Preferably, the amount of heat in the structural member is determined from temperature changes. If the amount of heat is determined from temperature changes in structural members, the extent of damage to buildings caused by earthquakes can be measured with greater accuracy. Furthermore, since temperature is easy to measure, the extent of damage to buildings caused by earthquakes can be measured more easily.
In addition to the temperature change, the amount of heat of the structural member can also be determined from, for example, the amount of power generated by a thermoelectric conversion element or the like.

It is preferable that the measurement unit acquires data on the amount of plastic heat generated by the structural members constituting the building and data on the amount of heat due to the thermoelastic effect. If the plastic calorific value and the heat amount due to the thermoelastic effect are acquired, the cumulative plastic strain of the structural member and the number of elastic vibrations can be determined by a calculation unit described later.

Preferably, the measuring section includes a temperature sensor. If the measurement unit includes a temperature sensor, the amount of heat in the structural member can be determined using the temperature sensor. The measurement unit preferably includes a temperature sensor installed on the structural member, and even more preferably measures the temperature using a temperature sensor installed on the surface of the structural member.
Here, as the temperature sensor, those mentioned 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. Be prepared.

When the measuring section includes a temperature sensor, it is preferable that the measuring section further includes another sensor. If other sensors are further provided, the degree of damage to buildings caused by earthquakes can be measured with even greater precision.
Here, as other sensors, those mentioned above can be used as appropriate.

<Calculation part>
The calculation unit calculates the degree of damage to the building based on the amount of heat in the structural members.

The degree of damage to the building is preferably determined using the cumulative plastic strain of the structural member determined from the amount of plastic heat generation and the number of elastic vibrations determined from the amount of heat due to 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 the building due to an earthquake can be measured with higher accuracy.
Further, in order to determine the degree of damage, it is preferable to further use the plastic strain amplitude for each half cycle of elastic vibration of the structural member. If the degree of damage is further determined using the plastic strain amplitude, the degree of damage to buildings caused by earthquakes can be measured with even greater precision.
Note that the cumulative plastic strain, the number of elastic vibrations, and the plastic strain amplitude can be determined by the method described above.

<Communication Department>
The communication unit includes a communication system that transmits data on the amount of heat acquired by the measurement unit to the outside.
Here, as the communication system, those mentioned above can be used as appropriate.
Note that the communication unit generally includes a receiver that receives the transmitted data on the amount of heat.

<Control unit>
The control unit includes a control device that automatically performs various operations using a control circuit.
Here, as the control circuit, those described above can be used as appropriate.

<Power source>
As the power source, those mentioned above can be used as appropriate.

Hereinafter, the present invention will be specifically explained based on test examples, but the present invention is not limited to these test examples.

(Test example 1)
<Preparation of test specimen>
Steel material (SS400) was cut out to prepare a test specimen 30 with a length (vertical direction in FIG. 7) of 20 cm, a width (horizontal direction of FIG. 7) of 10 cm, and a cross section of 20 mm square (not shown) as shown in FIG. .

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

<Test results>
Simultaneously with the start of vibration, a temperature rise in the test body 30 was confirmed by a metal thermocouple, and in addition to a gradual temperature rise, minute and periodic temperature changes were also confirmed. The final temperature at point P of the test specimen 30 reached 100°C.
The amount of plastic heat generation was determined from the measured temperature value, and the cumulative plastic strain was determined from this amount of plastic heat generation, and it was found to be approximately equal to the cumulative plastic strain determined from the amount of displacement. Further, the amount of heat due to the thermoelastic effect was determined from the measured temperature value, and the number of elastic vibrations was determined from the amount of heat due to the thermoelastic effect, and it was found to be the same as the number of vibrations.
Furthermore, the temperature data measured above was transmitted by the communication system and could be received by a PC located 10 meters away.

(Test example 2)
Instead of a metal thermocouple as a sensor, a CNT thermoelectric conversion element (SGCNT is used as a semiconductor) manufactured to match the shape of the test specimen was used, and vibration tests were conducted at both frequencies of 3 Hz and 10 Hz. The operations and tests were conducted in the same manner as in Test Example 1, except that. Note that the CNT thermoelectric conversion element used was a sheet-like one having a thickness of 1 mm and having performance of Voc: 0.6 V and Isc: 0.5 mA at a temperature difference between 120° C. and 25° C. Here, the electric power generated by the CNT thermoelectric conversion element was also used as a power source using a boost converter that converted the output to 3V.

<Test results>
As in Test Example 1, a gradual temperature increase and minute and periodic temperature changes were observed.
As in Test Example 1, the cumulative plastic strain was determined from the measured temperature value and was approximately equal to the cumulative plastic strain determined from the displacement amount. Further, when the number of elastic vibrations was determined from the measured temperature value, it was found to be the same as the number of vibrations.
Furthermore, when the temperature exceeded 60°C, it became possible to measure the temperature using only the power generated by the CNT thermoelectric conversion element. That is, it means that the CNT thermoelectric conversion element functioned as 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 the measurement, and the temperature could be accurately measured to the end.

(Test example 3)
The operation and test were conducted 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 a sensor. The inorganic thermoelectric element has a performance of Voc: 0.1V and Isc: 5mA at a temperature difference between 120°C and 25°C, and is a 2cm square plate (0.5mm thick). there was. Further, as in Test Example 2, the electric power generated by the inorganic thermoelectric element was also used as a power source using a boost converter that converted the output to 3V.

<Test results>
From the start of measurement, the inorganic thermoelectric element was damaged and temperature measurement became impossible after approximately 180 seconds at a frequency of 3 Hz and approximately 80 seconds at a frequency of 10 Hz. A temperature rise and minute and periodic temperature changes were confirmed.
As in Test Example 2, the cumulative plastic strain was determined from the measured temperature value and was approximately equal to the cumulative plastic strain determined from the displacement amount. Further, when the number of elastic vibrations was determined from the measured temperature value, it was found to be the same as the number of vibrations.
Further, as in Test Example 2, when the temperature exceeded 60° C., it became possible to measure the temperature using power generation only by the inorganic thermoelectric element.

(Test example 4)
<Preparation of test building>
As shown in FIG. 8, a test structure 40 was fabricated, which consisted of a steel frame 41, a test body 42 located between the steel frames 41 installed diagonally, and a metal thermocouple 43 installed on the test body 42. .

<Vibration test>
A vibration test was conducted using the test building 40 shown in FIG. 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 number of vibrations of 900 times (about 5 minutes). Other operations and tests were performed in the same manner as in Test Example 1. The dynamic jack used was "Portable Hydraulic Exciter Force Simulator EHF-JF20kNV-100-A10" manufactured by Shimadzu Corporation.

<Test results>
As in Test Example 1, a gradual temperature increase and minute and periodic temperature changes were observed.
As in Test Example 1, the cumulative plastic strain was determined from the measured temperature value and was approximately equal to the cumulative plastic strain determined from the amount of displacement. Further, when the number of elastic vibrations was determined from the measured temperature value, it was found to be the same as the number of vibrations.

(Test Example 5)
<Preparation of test building>
As shown in FIG. 9, a test building 40 consisting of a steel frame 41 and metal thermocouples 43 installed at the corners of the steel frame 41 was fabricated.

<Vibration test>
A vibration test was conducted in the same manner as Test Example 4 using the test building 40 shown in FIG.

<Test results>
Although it was not clear compared to Test Example 4, a gradual temperature increase and minute and periodic temperature changes were confirmed.
As in Test Example 4, the cumulative plastic strain was determined from the measured temperature value and was approximately equal to the cumulative plastic strain determined from the amount of displacement. Further, when the number of elastic vibrations was determined from the measured temperature value, it was found to be the same as the number of vibrations.

(Comparative test example 1)
The operation and test were conducted in the same manner as in Test Example 1, except that a strain gauge was used instead of a metal thermocouple as a sensor.

<Test results>
Although it was possible to determine the number of elastic vibrations from the measured values of the strain gauge, it was not possible to determine the cumulative plastic strain.

10: Building 11: Foundation 12: Column 13: Beam 14: Bracing 15: Damper 16: Temperature sensor 20: Measurement system 21: Measurement section 22: Calculation section 23: Communication section 24: Control section 30: Test object 40: Test Building 41: Steel frame 42: Test body 43: Metal thermocouple

Claims

A method for measuring damage to buildings due to earthquakes, the method comprising:
A measuring method that determines the degree of damage to the building based on the amount of heat of structural members that make up the building.
The amount of heat includes a plastic calorific value and a heat amount due to a thermoelastic effect,
The measuring 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 generation and the number of elastic vibrations determined from the amount of heat due to the thermoelastic effect.
The measuring method according to claim 1 or 2, wherein the amount of heat is determined from a temperature change of the structural member.
The measuring method according to any one of claims 1 to 3, wherein the structural member is a damper.
The measuring method according to any one of claims 1 to 4, wherein the amount of heat is determined by a temperature sensor installed on the structural member.
The measurement method according to claim 5, wherein the temperature sensor is operated by energy of the earthquake.
The measurement method according to claim 5 or 6, wherein the temperature sensor is a thermoelectric conversion element.
The measurement method according to claim 7, wherein the thermoelectric conversion element has flexibility.
The measurement method according to claim 7 or 8, wherein the thermoelectric conversion element includes a semiconductor containing carbon nanotubes.
The measurement method according to claim 9, wherein the carbon nanotubes include single-walled carbon nanotubes.
The measuring method according to any one of claims 5 to 10, further comprising using a sensor different from the temperature sensor.
The measuring method according to any one of claims 1 to 11, which uses a communication system that transmits the data of the amount of heat to the outside.
The measurement method according to claim 12, wherein the communication system is a wireless communication system.
A system for measuring damage to buildings due to earthquakes,
a measurement unit that acquires data on the amount of heat of structural members that constitute the building;
a calculation unit that calculates the degree of damage to the structure based on the amount of heat;
A measurement system equipped with.