JP7714500B2 - Earthquake impact assessment device and earthquake impact assessment method - Google Patents

Description

The present invention relates to an earthquake impact assessment device and an earthquake impact assessment method.

Patent Document 1 discloses a device that determines the condition of a building by determining how much the building's natural frequency has changed before and after an earthquake.

JP 2018-59718 A

The device described in Patent Document 1 evaluates the integrity of the entire building, but to more accurately evaluate the impact of an earthquake on a building, it is necessary to understand the degree to which each of the steel components that make up the building deformed during the earthquake. However, one possible way to measure the amount of deformation that occurred in each steel component during an earthquake would be to install measurement sensors on each steel component, continuously measure using a recorder, and then analyze the data after the earthquake. However, this would increase measurement costs and the amount of analysis work required.

The purpose of this invention is to make it possible to easily evaluate the impact of an earthquake on the steel members that make up a steel-framed building.

The present invention is an earthquake impact assessment device that assesses the impact of an earthquake on steel members that make up a steel-framed building. It includes an acquisition unit that acquires the range of the plasticity region of the steel member, a calculation unit that calculates the plasticity factor of the steel member during an earthquake based on the range of the plasticity region, and an evaluation unit that assesses the impact of the earthquake on the steel member based on the plasticity factor.

The present invention also provides an earthquake impact assessment method for assessing the impact of an earthquake on steel members that make up a steel-framed building, and includes the steps of obtaining the range of the plasticity region of the steel members, calculating the plasticity factor of the steel members during an earthquake based on the range of the plasticity region, and assessing the impact of the earthquake on the steel members based on the plasticity factor.

This invention makes it easy to evaluate the impact of an earthquake on steel members that make up a steel-framed building.

1 is a diagram showing an example of a steel member (beam member) to be evaluated by an earthquake impact assessment device according to an embodiment of the present invention. FIG. 10 is a graph showing the relationship between the rotation angle and the bending moment in the cross section of a beam member. FIG. 10 is a conceptual diagram for explaining a plastic region that occurs in a beam member. 1 is a graph obtained by a constant amplitude cyclic loading test. 10 is a graph showing the relationship between the number of repetitions and the plasticized region in a beam member obtained by a constant amplitude cyclic loading test. 1 is a graph showing the relationship between the plasticized region and the yield plasticity ratio in a beam member. 1 is a graph showing the relationship between fracture life and plasticity rate in a beam member. 1 is a block diagram showing the configuration of an earthquake impact assessment system according to an embodiment of the present invention. 1 is a flowchart showing a processing procedure performed in an earthquake influence assessment device according to an embodiment of the present invention. 1 is a graph showing the relationship between the yield plasticity rate and the plasticized region in a beam member obtained by a monotonic loading test. 1 is a graph showing the relationship between the plasticized region and the yield plasticity ratio in a beam member obtained by a monotonic loading test.

The following describes an earthquake impact assessment device and earthquake impact assessment method according to an embodiment of the present invention, with reference to the drawings.

An earthquake impact assessment device 10 according to an embodiment of the present invention is a device for post-earthquake assessment of the impact of an earthquake on steel members such as beams and columns that make up a steel-framed building. Below, we will explain the post-earthquake assessment of the impact of an earthquake on a beam member 2 that is welded to a column member 1 that is erected vertically and arranged horizontally, as shown in Figure 1. Note that the steel members that are the subject of assessment by the earthquake impact assessment device 10 are not limited to column member 1, but may also be steel-framed column members or brace materials.

The beam member 2 is an H-shaped steel material having a pair of flange portions 3, 4 and a web portion 5 sandwiched between the pair of flange portions 3, 4. It is a so-called built H-shaped steel formed by welding a pair of steel plates that form the pair of flange portions 3, 4 to a steel plate that forms the web portion 5. The beam member 2 may also be a rolled H-shaped steel formed by rolling.

The beam member 2 is joined to the column member 1, which is a steel pipe column, by welding a pair of flanges 3, 4 to a pair of diaphragms 7 provided on the column member 1, with the web portion 5 temporarily joined to a gusset plate 6 provided on the column member 1 via high-strength bolts (not shown). Note that the joining of the web portion 5 to the column member 1 is not limited to bolting using high-strength bolts, and may also be performed by directly welding the end faces of the web portion 5 to the column member 1.

When a beam member 2 joined to a column member 1 in this way is damaged by an earthquake to the extent that permanent strain (residual strain) remains, the mill scale and fire-resistant coating covering the flanges 3 and 4 peel off in the areas where permanent strain has occurred. This makes it possible to visually determine the extent to which the beam member 2 has become plastic, from the joint with the column member 1, which is the fixed end of the beam member 2.

In addition, to measure the area in which the beam member 2 has become plastic, measurement sensors such as strain gauges or optical fibers can be placed in advance along the material axis direction (longitudinal direction) of the beam member 2, and the area in which strain (permanent strain) is detected by the measurement sensor after an earthquake can be determined as the area in which the beam member 2 has become plastic.

It is also possible to remove the fire-resistant coating covering the flanges 3 and 4, measure the hardness of the components, and determine the range where hardness has increased due to permanent strain as the range where the beam component 2 has become plastic.

In this way, it is possible to determine the extent to which beam members 2 have become plastic after an earthquake, but to more accurately assess the impact of the earthquake on beam members 2, it is necessary to determine the extent to which beam members 2 deformed during the earthquake. However, one way to measure the amount of deformation that occurred in beam members 2 during an earthquake would be to install measurement sensors on each beam member 2, take constant measurements using a recorder, and then analyze the results after the earthquake. However, this increases the cost of measurement and may also increase the amount of work required for analysis.

In this embodiment, the extent of the plasticized area of the beam member 2, as determined after an earthquake using the various methods described above, is used to estimate the extent of damage the beam member 2 sustained during the earthquake.

Here, the plastic deformation range Ly of the beam member 2 identified after an earthquake as described above is the location where deformation has exceeded the yield moment My, where the yield moment My is the moment when the beam member 2 deviates from the line of elastic gradient K in the relationship between the rotation angle θ and bending moment M in the cross section of the beam member 2 shown in Figure 2.For example, as shown in Figure 3, this occurs over a specified range from the joint with the column member 1, which is the fixed end of the beam member 2.

Figure 2 is a graph showing the results of a so-called static monotonic loading test, in which the load is stopped at a certain load or deformation and the degree of strain and deformation of the beam member 2 is measured. The graph shows the relationship between the rotation angle θ at the cross section of the beam member 2 and the bending moment M. Figure 3 is a moment diagram showing the bending moment M in the axial direction (longitudinal direction) of the beam member 2 when a load is applied to a specified loading point on the beam member 2.

As shown in Figure 3, when a downward load P acts on a loading point a predetermined distance L away from the joint between the beam member 2 and the column member 1, the bending moment M gradually increases from the loading point toward the joint, reaching a maximum (M = P * L) at the joint. The portion where the bending moment M exceeds the yield moment My becomes plastic and enters the plastic range Ly. The same is true when an upward load (-P) acts on the loading point.

The relationship between the magnitude of the load P and the size of the plastic range Ly shown in Figure 3, i.e., the relationship between the magnitude of the bending moment M and the size of the plastic range Ly, can be expressed mathematically as shown in Equation 1 below.

In the above equation (1), M is the bending moment at the end of beam member 2, L is the distance from the joint between beam member 2 and column member 1 to the loading point, and My is the yield moment of beam member 2. The loading point is set from a bending moment diagram obtained by taking into account the long-term load and earthquake load of the target beam.

As is clear from the above equation (1), the larger the bending moment M at the end of the beam member 2, the larger the plasticity range Ly. When the bending moment M at the end of the beam member 2 is smaller than the yield moment My, i.e., when the load P is relatively small, the plasticity range Ly does not occur in the beam member 2. Note that the plasticity range Ly refers to the range that includes the areas where the surfaces of the flange portions 3 and 4 of the beam member 2 are slightly plasticized, and does not mean the range where the entire cross section of the beam member 2 is plasticized.

In the following, the parameter obtained by dividing the plastic range Ly that occurs in the beam member 2 over a specified range from the joint by the beam depth H of the beam member 2 and making it dimensionless will be referred to as the plastic range (Ly/H).

Furthermore, in the following description, in the relationship between the rotation angle θ and the bending moment M in the cross section of the beam member 2 shown in Figure 2, the rotation angle θ when it deviates from the line of the elastic gradient K will be referred to as the yield deformation θy, and the plasticity ratio calculated using the yield deformation θy as the denominator will be referred to as the yield plasticity ratio μy.

Note that when the plasticity factor μ based on full plastic load reaches 1, it means that the flange portions 3, 4, etc. of the beam member 2 have completely yielded, and the entire cross section has become plastic. Therefore, it is not an appropriate indicator of the progression of plasticity, such as the gradual progression of plasticity from the surfaces of the flange portions 3, 4 of the beam member 2. For this reason, the yield plasticity factor μy defined above is used.

Next, we will explain the relationship between the plastic region (Ly/H) and the yield plasticity ratio μy obtained from the results of a constant amplitude cyclic loading test in which the loading point of the beam member 2 shown in Figure 3 is displaced at a constant amplitude, with reference to Figures 4 to 6.

Figure 4 is a graph showing the general relationship between the yield plasticity ratio μy obtained from a constant amplitude cyclic loading test and the bending moment M. Figure 5 is a graph showing the general relationship between the number of repetitions N and the plastic region (Ly/H) obtained from a constant amplitude cyclic loading test conducted at multiple yield plasticity ratios μy. Figure 6 is a graph showing the relationship between the plastic region (Ly/H) obtained from the graph in Figure 5 and the yield plasticity ratio μy at a constant amplitude.

In a constant amplitude cyclic loading test, the beam member 2 is repeatedly loaded until it breaks, so as to achieve a predetermined yield plasticity modulus μy, and the strain occurring in the beam member 2 is measured at any time using multiple strain gauges installed along the material axis (longitudinal direction) of the beam member 2 and strain measurement sensors such as optical fibers installed along the material axis direction.

Generally, when the loading point is repeatedly displaced at a constant amplitude, the bending moment M at the end of the beam member 2 gradually increases as the number of repetitions N increases, as shown in Figure 4. In other words, the plastic region (Ly/H) of the beam member 2 gradually increases as the number of repetitions N increases.

Here, in a constant amplitude cyclic loading test, the area where strain is detected by the strain measurement sensor during one oscillation of the loading point can be considered to be the area where plasticization has progressed as the bending moment M exceeds the yield moment My, i.e., the plasticized area (Ly/H) described above. Therefore, by determining the size of the plasticized area (Ly/H) based on the detection value of the strain measurement sensor each time the loading point oscillates, it is possible to determine to what extent the plasticized area (Ly/H) will expand at a given yield plasticity ratio μy depending on the number of cycles N.

As shown in Figure 5, the plastic region (Ly/H) determined each time the loading point is oscillated increases with the number of cycles N for all yield plasticity factors μy1, μy2, and μy3, and eventually tends to approach a constant value. The first yield plasticity factor μy1 shown in Figure 5 corresponds to the case where the yield plasticity factor μy is greater than 1, the second yield plasticity factor μy2 corresponds to the case where the yield plasticity factor μy is greater than the first yield plasticity factor μy1, and the third yield plasticity factor μy3 corresponds to the case where the yield plasticity factor μy is greater than the second yield plasticity factor μy2.

Note that the limit number of repetitions N in Figure 5 is not limited to the number of times until the beam member 2 breaks, but may be any number of times until no change in the size of the plasticized region (Ly/H) is observed. For example, it may be the number of times until the strength of the beam member 2 decreases to approximately 80 to 90% of the maximum load.

The size of the plastic region (Ly/H) asymptotically approached at each of the yield plasticity factors μy1, μy2, and μy3 obtained in this way is plotted on a graph, as shown in Figure 6, with the size of the plastic region (Ly/H) on the horizontal axis and the yield plasticity factor μy at a constant amplitude on the vertical axis. By finding an approximation line for the multiple plotted points, a graph of the linear function represented by relational equation A is obtained.

From relational expression A, which shows the relationship between the range of the plastic region (Ly/H) and the yield plasticity modulus μy at a constant amplitude, it is possible to estimate the final size of the plastic region (Ly/H) when a constant amplitude is applied at a certain yield plasticity modulus μy.

In other words, if the plastic deformation range Ly of the beam member 2 after an earthquake can be determined using the various methods described above, and the magnitude of the beam depth H of the beam member 2 can be determined from drawings, etc., then the yield plasticity ratio μy, which indicates the maximum deformation (amplitude) of the beam member 2 during the earthquake, can be estimated based on relational equation A.

In addition, by creating the performance curve (S-N curve) shown in Figure 7 from the results of a constant amplitude cyclic loading test, it is possible to estimate the fracture life Nf of the beam member 2 based on this performance curve and the earthquake yield plasticity factor μy estimated from the above-mentioned relational equation A. Specifically, the fracture life Nf is generally estimated using the following equation 2.

In the above equation 2, μ is the plasticity factor, C is a coefficient set depending on the joint type at the beam end, etc., and β is the slope of the evaluation formula, which is experimentally set to a value of approximately 1/3.

The plasticity factor μ in the performance curve is based on the full plastic load, which is different from the yield plasticity factor μy mentioned above. Therefore, to estimate the fracture life Nf based on the performance curve, it is necessary to convert the yield plasticity factor μy to the plasticity factor μ.

The conversion factor used to convert the yield plasticity modulus μy to the plasticity modulus μ varies depending on the cross-sectional shape of the beam member 2 and the specific shape of the joint between the beam member 2 and the column member 1, such as the shape of the scallops formed in the web portion 5, and is determined experimentally or by FEM (Finite Element Method) analysis. The specific magnitude of the conversion factor is around 0.7.

Furthermore, since the yield plasticity ratio μy obtained from relational equation A is the maximum degree of deformation that is estimated to have occurred in the beam member 2 during an earthquake, the fracture life Nf estimated based on the performance curve may be a value shorter than the actual fracture life.

For this reason, it is possible to assume that the yield plasticity factor μy obtained from relational equation A was the maximum value based on actual seismic waveforms measured at nearby observation points, and estimate that the beam member 2 vibrated at multiple yield plasticity factors μy smaller than this, thereby calculating the fracture life Nf evaluated using the linear cumulative damage rule (Miner's rule).

Furthermore, by obtaining the number of vibrations n (number of vibrations) of the floors of a steel-framed building in which beam member 2 is installed, it is possible to obtain the damage level D of beam member 2 by dividing the number of vibrations n by the fracture life Nf, and further use the damage level D to obtain the remaining performance (1-D) and margin (1-D)/D.

In order to estimate the extent of damage sustained by a beam member 2 (steel member) during an earthquake based on the above-described characteristics, the earthquake impact assessment device 10 according to this embodiment, as shown in FIG. 8, includes an acquisition unit 11 that acquires the plasticization range Ly, which is the range of the plasticized region of the beam member 2 (steel member); a calculation unit 12 that calculates the yield plasticity modulus μy (plasticity modulus) of the beam member 2 during an earthquake based on the acquired plasticization range Ly; an evaluation unit 13 that evaluates the impact of the earthquake on the beam member 2 based on the yield plasticity modulus μy; and a memory unit 14 that stores relational equations, coefficients, etc. used by the calculation unit 12 and evaluation unit 13, as well as calculation results and evaluation results.

Specifically, the earthquake impact assessment device 10 is composed of a microcomputer equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and I/O interface (Input/Output Interface). The RAM stores data used in CPU processing, the ROM stores the CPU's control programs and other information in advance, and the I/O interface is used for inputting and outputting information to and from the input unit 20, display unit 30, and measurement unit 40 connected to the earthquake impact assessment device 10. The RAM and ROM correspond to the memory unit 14. Note that the acquisition unit 11, calculation unit 12, and evaluation unit 13 represent the functions of the earthquake impact assessment device 10 as virtual units, and do not necessarily exist physically.

The input unit 20 connected to the earthquake impact assessment device 10 is a keyboard or touch panel, and is used by the operator to input dimensions related to the plasticization range Ly. The display unit 30 connected to the earthquake impact assessment device 10 is a monitor screen that displays calculation results and assessment results, and also displays values entered via the input unit 20.

The earthquake impact assessment device 10 may also be connected to a measurement unit 40 capable of measuring the plasticization range Ly. The measurement unit 40 is, for example, a device capable of measuring the detection values of strain measurement sensors such as strain gauges or optical fibers installed along the material axis direction of the beam member 2. The measurement unit 40 may also include a vibration recorder that records the number of vibrations n of the story on which the beam member 2 is installed.

In this way, the earthquake impact assessment device 10 and the equipment connected to the earthquake impact assessment device 10 form an earthquake impact assessment system 100.

Next, the earthquake impact assessment method performed by the earthquake impact assessment device 10 will be explained with reference to the flowchart in Figure 9.

First, in step S11, the acquisition unit 11 acquires the plasticization range Ly, which is the range of the plasticized region of the beam member 2 (steel member). Specifically, the length of the portion where the black scale (mill scale) has peeled off and the length of the portion where residual strain has been detected by the measurement unit 40 are input by the worker via the input unit 20. These input values are acquired by the acquisition unit 11 as the plasticization range Ly. Note that the length of the portion where residual strain has been detected may be sent directly from the measurement unit 40 to the acquisition unit 11 by connecting the measurement unit 40 to the earthquake impact assessment device 10.

In the following step S12, the calculation unit 12 calculates the yield plasticity ratio μy of the beam member 2 during an earthquake based on the plasticity range Ly acquired by the acquisition unit 11 and the beam depth H previously stored in the memory unit 14.

Specifically, the yield plasticity ratio μy during an earthquake, which indicates the maximum deformation of the beam member 2 from the plastic region (Ly/H) during an earthquake, is calculated using relational expression A shown in Figure 6, which was formulated in advance based on the change in the range of the plastic region (Ly/H) relative to the number of cycles N shown in Figure 5 as described above. Note that relational expression A is stored in advance in the memory unit 14.

Next, in step S13, the calculation unit 12 calculates the fracture life Nf (number of fracture repetitions) until the beam member 2 (steel member) fractures. Specifically, the fracture life Nf of the beam member 2 is calculated using the above equation 2, which is pre-stored in the memory unit 14.

As mentioned above, the plasticity factor μ of the performance curve used in step S13 is based on the full plastic load, which is a different standard from the yield plasticity factor μy calculated in step S12. Therefore, the yield plasticity factor μy calculated in step S12 is converted in advance using a conversion factor pre-stored in memory unit 14.

In the following step S14, the evaluation unit 13 evaluates the impact of the earthquake on the beam member 2 (steel member) based on the fracture life Nf (number of fracture repetitions) calculated by the calculation unit 12 and the number of shakings n of the floor on which the beam member 2 is installed.

Specifically, the damage level D of the beam member 2 is calculated by dividing the number of vibrations n by the fracture life Nf. If the damage level D does not exceed 1, the beam member 2 is determined to be sound; if the damage level D is 1 or greater, the beam member 2 is determined to be unsound.

The results of the evaluation performed by the evaluation unit 13 in this manner are displayed on the display unit 30 and stored in the memory unit 14. Note that the evaluation based on the damage level D may indicate not only whether the object is healthy or not, but also the level of damage depending on the magnitude of the value of the damage level D.

When the evaluation unit 13 evaluates the damage level D in step S14, the number of shakings n during an earthquake for the floor of the steel-framed building in which the beam member 2 is installed is acquired in advance from the input unit 20 or the measurement unit 40 via the acquisition unit 11. Note that the evaluation performed by the evaluation unit 13 in step S14 is not limited to being based on the damage level D, but may also be based on the remaining performance (1-D) or the margin (1-D)/D.

In the following step S15, the evaluation unit 13 evaluates the impact of the earthquake on the beam member 2 (steel member) based on the yield plasticity factor μy calculated in step S12 and the allowable plasticity factor μa preset for each beam member 2.

Specifically, the yield plasticity factor μy is compared with the allowable plasticity factor μa, and if the yield plasticity factor μy does not exceed the allowable plasticity factor μa, the beam member 2 is determined to be sound; if the yield plasticity factor μy is equal to or greater than the allowable plasticity factor μa, the beam member 2 is determined to be unsound.

The results of the evaluation performed by the evaluation unit 13 in this manner are displayed on the display unit 30 and stored in the memory unit 14. The evaluation based on the yield plasticity factor μy and the allowable plasticity factor μa may indicate not only whether the structure is sound or not, but also the damage level according to the ratio of the yield plasticity factor μy to the allowable plasticity factor μa.

The allowable plasticity factor μa used for the evaluation in step S15 may be input via the input unit 20, or may be stored in advance in the memory unit 14. Note that if the allowable plasticity factor μa is based on the full plastic load, the yield plasticity factor μy calculated in step S12 is converted in advance using a conversion factor stored in advance in the memory unit 14.

After these steps, the earthquake impact assessment method performed by the earthquake impact assessment device 10 is completed, and the impact of the earthquake on the beam member 2 is evaluated.

The above embodiment provides the following advantages:

In the earthquake impact assessment device 10, the calculation unit 12 calculates the yield plasticity factor μy of the beam member 2 (steel member) during an earthquake based on the plasticity range Ly acquired by the acquisition unit 11, and the evaluation unit 13 evaluates the damage level D, which indicates the impact of the earthquake on the beam member 2, and the ratio of the yield plasticity factor μy to the allowable plasticity factor μa based on the calculated yield plasticity factor μy.

In this way, even if measurements of deformation of the beam member 2 (steel member) that occurred during an earthquake are not taken in real time, the impact of the earthquake on the beam member 2 can be easily evaluated after the earthquake by calculating the degree to which the beam member 2 deformed during the earthquake based on the plasticity range Ly obtained after the earthquake.

The above embodiment assumes a case where a beam member 2 (steel member) is repeatedly loaded by an earthquake, for example, a trench earthquake. In contrast, in cases where the beam member 2 (steel member) is significantly displaced by a single vibration, such as in a shallow earthquake, the impact of the earthquake on the beam member 2 can be evaluated after the earthquake using the following method.

Generally, in a shallow earthquake, unlike a trench earthquake, a single vibration causes a large displacement in the beam member 2 (steel member). Therefore, based on the results of the monotonic load test, it is possible to estimate the extent of damage sustained by the beam member 2 during the earthquake.

Here, the magnitudes of the bending moment M, yield moment My, and plastic range Ly are related by the above equation 1, so if the vertical axis of the graph in Figure 2, which shows the results of the monotonic loading test, is converted using the above equation 1 and the beam depth H of the beam member 2, the graph shown in Figure 10 is obtained. Note that in Figure 10, the horizontal axis is converted to the yield plasticity modulus μy, which is calculated using the yield deformation θy as the denominator.

From the graph shown in Figure 10, it is possible to estimate the size of the plastic region (Ly/H) when the beam member 2 is displaced at one time at a certain yield plasticity rate μy.

In other words, if the plastic deformation range Ly of the beam member 2 after a shallow earthquake can be determined using the various methods described above, and the magnitude of the beam depth H of the beam member 2 can be determined from drawings, etc., the yield plasticity ratio μy during an earthquake, which indicates the maximum degree of deformation of the beam member 2 during an earthquake, can be estimated from relational equation B shown in Figure 11, which is obtained by swapping the vertical and horizontal axes of the graph in Figure 10. Note that relational equation B is an approximate curve obtained from the graph obtained by swapping the vertical and horizontal axes of the graph in Figure 10.

By comparing the yield plasticity factor μy calculated in this way with the allowable plasticity factor μa preset for each beam member 2, it is possible to evaluate the impact on the beam member 2 (steel member) of a shallow earthquake.

The graph shown in Figure 11 has the same vertical and horizontal axes as the graph shown in Figure 6, and while the graph shown in Figure 6 shows the yield plasticity modulus μy at constant amplitude, i.e., the yield plasticity modulus μy under conditions similar to the shaking that occurs in a subduction zone earthquake, the graph shown in Figure 11 shows the yield plasticity modulus μy under monotonic loading, i.e., the yield plasticity modulus μy under conditions similar to the shaking that occurs in a shallow earthquake.

Therefore, in the case of a complex earthquake consisting of both a trench-type and a shallow-focus earthquake, the impact of the earthquake on beam member 2 (steel member) can be evaluated based on the yield plasticity factor μy calculated by adding together, in any ratio, the yield plasticity factor μy during the earthquake estimated from relational formula A and the yield plasticity factor μy during the earthquake estimated from relational formula B.

The above describes embodiments of the present invention, but these embodiments merely illustrate some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

10: Earthquake impact assessment device 2: Beam member (steel member)
11: Acquisition unit 12: Calculation unit 13: Evaluation unit

Claims (5)

An earthquake impact assessment device that evaluates the impact of an earthquake on steel members that make up a steel-framed building,
an acquisition unit that acquires a range of a plasticized region of the steel member;
a calculation unit that calculates a plasticity factor of the steel member during an earthquake based on the range of the plasticized region;
and an evaluation unit that evaluates the effect of an earthquake on the steel member based on the plasticity factor.
Earthquake impact assessment equipment. The calculation unit calculates the plasticity factor using a relational expression between the range of the plasticity region and the plasticity factor at a constant amplitude, the relational expression being formulated in advance based on a change in the range of the plasticity region with respect to the number of repetitions.
The earthquake impact assessment device according to claim 1 . The acquisition unit further acquires the number of vibrations of the steel-framed building during an earthquake,
The calculation unit calculates the number of repetitions until the steel member breaks based on the plasticity factor,
the evaluation unit evaluates the influence of the earthquake on the steel member based on the number of repetitions to fracture and the number of vibrations.
The earthquake impact assessment device according to claim 1 or 2. The acquisition unit further acquires an allowable plasticity factor of the steel member,
the evaluation unit evaluates the influence of the earthquake on the steel member based on the plasticity factor and the allowable plasticity factor.
The earthquake impact assessment device according to claim 1 or 2. An earthquake impact assessment method for assessing the impact of an earthquake on steel members constituting a steel-framed building, comprising:
A step of obtaining a range of a plasticized region of the steel member;
calculating a plasticity factor of the steel member during an earthquake based on the range of the plasticized region;
and evaluating the effect of the earthquake on the steel member based on the plasticity factor.
Earthquake impact assessment methods.