Seismic impact assessment device and seismic impact assessment method

Abstract

To easily evaluate the influence of an earthquake on a steel member constituting a building of steel frame construction.SOLUTION: An earthquake influence evaluation device 10 comprises: an acquisition unit 11 that acquires a ductility range Ly of a beam member 2; a calculation unit 12 that calculates a yield ductility factor μy of the beam member 2 during an earthquake based on the ductility range Ly; and an evaluation unit 13 that evaluates the influence of the earthquake on the beam member 2 based on the yield ductility factor μy.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an earthquake impact evaluation device and an earthquake impact evaluation method.

Background Art

[0002] Patent Document 1 discloses a device for grasping the state of a building based on how much the natural frequency of the building has changed before and after an earthquake.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the device described in Patent Document 1, the soundness of the entire building is evaluated. However, in order to more accurately evaluate the impact on the building during an earthquake, it is necessary to grasp how much each steel member constituting the building has deformed during the earthquake. However, in order to measure the amount of deformation generated in each steel member during an earthquake, for example, it is conceivable to install a measurement sensor or the like on each steel member, constantly measure with a recording meter, and perform analysis after the earthquake. However, there is a risk that the measurement cost and the number of analysis man-hours will increase.

[0005] An object of the present invention is to enable easy evaluation of the impact on steel members constituting a steel-frame building during an earthquake.

Means for Solving the Problems

[0006] The present invention relates to an earthquake impact evaluation device for evaluating the impact on steel members constituting a steel-frame building due to an earthquake, and includes an acquisition unit that acquires the range of the plasticized region of the steel member, a calculation unit that calculates the plastic strain rate of the steel member during an earthquake based on the range of the plasticized region, and an evaluation unit that evaluates the impact on the steel member due to the earthquake based on the plastic strain rate.

[0007] In addition, the present invention relates to an earthquake impact evaluation method for evaluating the impact on steel members constituting a steel-frame building due to an earthquake, and includes steps of acquiring the range of the plasticized region of the steel member, calculating the plastic strain rate of the steel member during an earthquake based on the range of the plasticized region, and evaluating the impact on the steel member due to the earthquake based on the plastic strain rate.

Advantages of the Invention

[0008] According to the present invention, it is possible to easily evaluate the impact on steel members constituting a steel-frame building due to an earthquake.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiment for Carrying Out the Invention

[0010] Hereinafter, with reference to the drawings, an earthquake impact evaluation apparatus and an earthquake impact evaluation method according to an embodiment of the present invention will be described.

[0011] The earthquake impact evaluation apparatus 10 according to an embodiment of the present invention is an apparatus for evaluating the impact received by steel members such as beams and columns constituting a steel frame building after an earthquake. Hereinafter, as shown in FIG. 1, the case where the impact received by the beam member 2 welded to the column member 1 erected along the vertical direction and arranged along the horizontal direction is evaluated after an earthquake will be described. Note that the steel member to be evaluated by the earthquake impact evaluation apparatus 10 is not limited to the column member 1, and may be a steel column member or a brace member made of steel.

[0012] The beam member 2 is an H-shaped steel having a pair of flange portions 3 and 4 and a web portion 5 sandwiched between the pair of flange portions 3 and 4, and is a so-called built-up H-shaped steel formed by welding a pair of steel plates serving as the pair of flange portions 3 and 4 to the steel plate serving as the web portion 5. Note that the beam member 2 may be a rolled H-shaped steel formed by rolling.

[0013] The beam member 2 is joined to the column member 1 by welding the pair of flange portions 3 and 4 to the pair of diaphragms 7 provided on the column member 1, respectively, in a state where the web portion 5 is temporarily joined to the gusset plate 6 provided on the column member 1 which is a steel pipe column via high-strength bolts (not shown). Note that the joining of the web portion 5 to the column member 1 is not limited to bolt joining by high-strength bolts, and may be performed by directly welding the end face of the web portion 5 to the column member 1.

[0014] When the beam member 2 joined to the column member 1 in this way is damaged to such an extent that permanent strain (residual strain) remains due to an earthquake, peeling occurs in the mill scale or fireproof coating covering the flange portions 3 and 4 at the portion where the permanent strain has occurred. For this reason, it is possible to visually determine the range over which the beam member 2 has been plasticized from the joint portion with the column member 1 which is the fixed end of the beam member 2.

[0015] Also, in order to measure the region where the beam member 2 has been plasticized, measurement sensors such as strain gauges or optical fibers are arranged in advance along the material axis direction (longitudinal direction) of the beam member 2, and the range in which strain (permanent strain) is detected by the measurement sensors after the earthquake is grasped as the range where the beam member 2 has been plasticized.

[0016] Also, it is possible to grasp the range where the hardness has increased due to the influence of the permanent strain by peeling the fireproof coating covering the flange portions 3 and 4 and measuring the hardness of the member as the range where the beam member 2 has been plasticized.

[0017] Although it is possible to grasp the range where the beam member 2 has been plasticized after the earthquake in this way, in order to more accurately evaluate the influence that the beam member 2 has received during the earthquake, it is necessary to grasp the extent to which the beam member 2 has deformed during the earthquake. However, in order to measure the amount of deformation that occurred in the beam member 2 during the earthquake, for example, it is conceivable to install measurement sensors on each beam member 2, perform constant measurement with a recording meter, and perform analysis after the earthquake, but there is a risk that the cost required for measurement increases and the man-hours required for analysis also increase.

[0018] Therefore, in this embodiment, the degree of damage to the beam member 2 during an earthquake is estimated by using the size of the plasticized range of the beam member 2 grasped after the earthquake by various methods as described above.

[0019] Here, the plasticized range Ly of the beam member 2 grasped after the earthquake as described above is the moment when it deviates from the line of the elastic gradient K in the relationship between the rotation angle θ and the bending moment M in the cross section of the beam member 2 shown in FIG. 2. When the moment is taken as the yield moment My, it is the portion where the deformation exceeds the yield moment My. For example, as shown in FIG. 3, it occurs over a predetermined range from the joint with the column member 1 which is the fixed end of the beam member 2.

[0020] FIG. 2 is a graph showing the results obtained by a so-called static monotonic loading test in which the load is stopped at every certain load or certain deformation to measure the strain and degree of deformation of the beam member 2, and shows the relationship between the rotation angle θ and the bending moment M in the cross section of the beam member 2. FIG. 3 is a moment diagram and shows the bending moment M in the material axis direction (longitudinal direction) of the beam member 2 when a load acts on a predetermined load point of the beam member 2.

[0021] As shown in FIG. 3, when a downward load P acts on a load point separated by a predetermined distance L from the joint between the beam member 2 and the column member 1, the bending moment M gradually increases from the load point toward the joint and becomes maximum (M = P·L) at the joint. And the portion where the bending moment M exceeds the yield moment My becomes the plasticized range Ly. This is the same when an upward load (-P) acts on the load point.

[0022] The relationship between the magnitude of the load P shown in FIG. 3 and the size of the plasticized range Ly, that is, the relationship between the magnitude of the bending moment M and the size of the plasticized range Ly is expressed as Equation 1 below.

[0023]

Equation

[0024] In the above formula (1), M is the bending moment at the end of the beam member 2, L is the distance from the joint of the beam member 2 and the column member 1 to the load point, and My is the yield moment of the beam member 2. The load point is set from a bending moment diagram or the like obtained by considering the long-term load and the seismic load of the target beam.

[0025] As is apparent from the above formula (1), the larger the bending moment M at the end of the beam member 2, the larger the plasticized range Ly. When the bending moment M at the end of the beam member 2 is smaller than the yield moment My, that is, when the load P is relatively small, no plasticized range Ly occurs in the beam member 2. The plasticized range Ly means a range including a portion where the surfaces of the flange portions 3 and 4 of the beam member 2 are slightly plasticized, and does not mean a range where the entire cross-section of the beam member 2 is plasticized.

[0026] Hereinafter, a parameter obtained by dividing the plasticized range Ly generated in the beam member 2 over a predetermined range from the joint by the beam height H of the beam member 2 and making it dimensionless will be described as the plasticized region (Ly / H).

[0027] Further, hereinafter, in the relationship between the rotation angle θ and the bending moment M in the cross-section of the beam member 2 shown in FIG. 2, the rotation angle θ when deviating from the line of the elastic gradient K is defined as the yield deformation θy, and the plastic strain calculated using the yield deformation θy as the denominator is defined as the yield plastic strain μy.

[0028] Note that, for the plastic strain μ based on the full plastic load, when the plastic strain μ becomes 1, it means that the flange portions 3 and 4 of the beam member 2 are completely yielded and the entire cross-section is in a plasticized state. Therefore, it is not appropriate as an index indicating a situation where plasticization progresses, for example, a situation where plasticization gradually progresses from the surfaces of the flange portions 3 and 4 of the beam member 2. For this reason, the yield plastic strain μy defined as described above is used.

[0029] Next, with reference to FIGS. 4 to 6, the relationship between the plasticized region (Ly / H) and the yield plastic strain rate μy obtained from the results of a constant amplitude repeated loading test in which the loading point of the beam member 2 shown in FIG. 3 is displaced with a constant amplitude will be described.

[0030] FIG. 4 is a graph showing the general relationship between the yield plastic strain rate μy and the bending moment M obtained from a constant amplitude repeated loading test, FIG. 5 is a graph showing the general relationship between the number of repetitions N and the plasticized region (Ly / H) obtained from a constant amplitude repeated loading test performed at a plurality of yield plastic strain rates μy, and FIG. 6 is a graph showing the relationship between the plasticized region (Ly / H) obtained from the graph of FIG. 5 and the yield plastic strain rate μy at a constant amplitude.

[0031] In the constant amplitude repeated loading test, the beam member 2 is repeatedly loaded until it breaks so as to obtain a predetermined yield plastic strain rate μy, and the strain generated in the beam member 2 is measured at any time by strain measurement sensors such as a plurality of strain gauges provided along the material axis direction (longitudinal direction) of the beam member 2 and an optical fiber provided along the material axis direction.

[0032] Generally, when the loading point is repeatedly displaced with 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 FIG. 4. That is, the plasticized region (Ly / H) of the beam member 2 gradually increases as the number of repetitions N increases.

[0033] Here, in the constant amplitude repeated loading test, the region where it is detected by the strain measurement sensor that strain has occurred during one amplitude of the loading point is the region where plasticization has progressed because the bending moment M has exceeded the yield moment My, that is, it can be regarded as the above-mentioned plasticized region (Ly / H). Therefore, by grasping the size of the plasticized region (Ly / H) based on the detected value of the strain measurement sensor every time the loading point is displaced by one amplitude, it is possible to grasp how much the plasticized region (Ly / H) expands according to the number of repetitions N at a predetermined yield plastic strain rate μy.

[0034] Each time the loading point is displaced by one amplitude, the plasticized region (Ly / H) thus obtained increases with the number of repetitions N and eventually tends to approach a constant value, as shown in Fig. 5, regardless of the yield plastic strain rates μy1, μy2, μy3. The first yield plastic strain rate μy1 shown in Fig. 5 is the case where the yield plastic strain μy is greater than 1. The second yield plastic strain rate μy2 is the case where the yield plastic strain μy is greater than the first yield plastic strain rate μy1, and the third yield plastic strain rate μy3 is the case where the yield plastic strain μy is greater than the second yield plastic strain rate μy2, respectively.

[0035] Note that the limit number of repetitions N in Fig. 5 is not limited to the number of times until the beam member 2 breaks, but may be any number of times when no change is observed in the size of the plasticized region (Ly / H). For example, it may be the number of times until the yield strength of the beam member 2 decreases to about 80 - 90% of the maximum load.

[0036] The sizes of the plasticized regions (Ly / H) asymptotic at each of the obtained yield plastic strain rates μy1, μy2, μy3 are plotted on a graph with the horizontal axis representing the size of the plasticized region (Ly / H) and the vertical axis representing the yield plastic strain rate μy at a constant amplitude, as shown in Fig. 6. When an approximate straight line of the plotted multiple points is obtained, a graph of the linear function represented by relational expression A is acquired.

[0037] From relational expression A showing the relationship between the range of the plasticized region (Ly / H) and the yield plastic strain rate μy at a constant amplitude, it is possible to estimate to what extent the plasticized region (Ly / H) will ultimately be when the beam is displaced by a constant amplitude at a certain yield plastic strain rate μy.

[0038] In other words, if the plasticized range Ly of the beam member 2 after an earthquake is grasped by various methods as described above, and the size of the beam height H of the beam member 2 is grasped from the drawing or the like, the yield plastic strain rate μy indicating the maximum deformation (amplitude) of the beam member 2 during the earthquake can be estimated based on relational expression A.

[0039] Also, by creating a performance curve (S-N curve) shown in Fig. 7 from the results of a constant amplitude repeated loading test, it is also possible to estimate the fracture life Nf of the beam member 2 based on this performance curve and the yield plastic strain μy at the time of earthquake estimated from the above relational expression A. Specifically, the fracture life Nf is generally estimated by the following Equation 2.

[0040]

Equation

[0041] In Equation 2 above, μ is the plastic strain, C is a coefficient set according to the joint form at the beam end, etc., and β is the slope of the evaluation formula and is experimentally set to a value of about 1 / 3.

[0042] Here, the plastic strain μ in the performance curve is based on the full plastic load and has a different reference from the above yield plastic strain μy. Therefore, in order to estimate the fracture life Nf based on the performance curve, it is necessary to convert the yield plastic strain μy to the plastic strain μ.

[0043] The conversion coefficient for converting the yield plastic strain μy to the plastic strain 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, for example, the shape of the scallop formed in the web portion 5, and is obtained experimentally or by FEM (Finite Element Method) analysis. The specific magnitude of the conversion coefficient is around 0.7.

[0044] Also, since the yield plastic strain μy obtained from the relational expression A is the maximum degree of deformation estimated that the beam member 2 was deformed during an earthquake, the fracture life Nf estimated based on the performance curve may be a value smaller than the actual fracture life.

[0045] Therefore, based on the actual seismic waveforms measured at adjacent observation points, it is assumed that the yield plastic strain rate μy obtained from relational expression A was the maximum value, and it is estimated that the beam member 2 was vibrating with a plurality of yield plastic strain rates μy smaller than this. Thus, the fracture life Nf evaluated by the linear cumulative damage rule (Miner's rule) may be calculated.

[0046] Also, by obtaining the number of shakes n (vibration times) of the story of the steel-frame building where the beam member 2 is provided, dividing the number of shakes n by the fracture life Nf, it is possible to obtain the damage degree D of the beam member 2, and further, using the damage degree D, to obtain the remaining performance (1 - D) or the margin (1 - D) / D.

[0047] In order to estimate the degree of damage suffered by the beam member 2 (steel member) during an earthquake based on the above characteristics, as shown in FIG. 8, the earthquake impact evaluation apparatus 10 according to the present embodiment 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 plastic strain rate μy (plastic strain rate) of the beam member 2 during an earthquake based on the acquired plasticization range Ly; an evaluation unit 13 that evaluates the impact suffered by the beam member 2 due to the earthquake based on the yield plastic strain rate μy; and a storage unit 14 that stores relational expressions, coefficients, etc. used by the calculation unit 12 and the evaluation unit 13, and stores calculation results and evaluation results.

[0048] Specifically, the earthquake impact evaluation apparatus 10 is composed of a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an I / O interface (Input / Output Interface). The RAM stores data in the processing of the CPU, the ROM stores in advance the control program of the CPU, etc., and the I / O interface is used for input / output of information with the input unit 20, the display unit 30, and the measurement unit 40 connected to the earthquake impact evaluation apparatus 10. The RAM and the ROM correspond to the storage unit 14. Note that the acquisition unit 11, the calculation unit 12, and the evaluation unit 13 are shown as virtual units of the respective functions of the earthquake impact evaluation apparatus 10 and do not mean physically existing.

[0049] The input unit 20 connected to the seismic impact evaluation device 10 is a keyboard or a touch panel, and is used for an operator to input dimensions related to the plasticized range Ly. The display unit 30 connected to the seismic impact evaluation device 10 is a monitor screen on which calculation results and evaluation results are displayed, and the values input via the input unit 20 are also displayed.

[0050] Further, a measuring unit 40 capable of measuring the plasticized range Ly may be connected to the seismic impact evaluation device 10. The measuring unit 40 is, for example, a device capable of measuring the detection values of strain measuring sensors such as strain gauges and optical fibers installed along the material axis direction of the beam member 2. Further, the measuring unit 40 may include a vibration recorder that records the number of shakes n of the floor where the beam member 2 is provided.

[0051] In this way, the seismic impact evaluation system 100 is constructed by the seismic impact evaluation device 10 and the devices connected to the seismic impact evaluation device 10.

[0052] Subsequently, the seismic impact evaluation method performed by the seismic impact evaluation device 10 will be described with reference to the flowchart of FIG. 9.

[0053] First, in step S11, the acquisition unit 11 acquires the plasticized range Ly, which is the range of the plasticized region of the beam member 2 (steel member). Specifically, the length of the part where the mill scale has been peeled off by the operator via the input unit 20 and the length of the part where the residual strain has been detected by the measuring unit 40 are input. These input values are acquired by the acquisition unit 11 as the plasticized range Ly. Note that the length of the part where the residual strain has been detected may be directly sent from the measuring unit 40 to the acquisition unit 11 by connecting the measuring unit 40 to the seismic impact evaluation device 10.

[0054] In the subsequent step S12, the calculation unit 12 calculates the yield plastic strain rate μy of the beam member 2 during an earthquake based on the plasticized range Ly acquired by the acquisition unit 11 and the beam height H prestored in the storage unit 14.

[0055] Specifically, based on the change in the range of the plasticization region (Ly / H) with respect to the number of repetitions N shown in FIG. 5 as described above, the yield plastic strain rate μy during an earthquake indicating the maximum deformation of the beam member 2 during an earthquake is calculated using the relational expression A shown in FIG. 6 established in advance. The relational expression A is stored in the storage unit 14 in advance.

[0056] Next, in step S13, the calculation unit 12 calculates the fracture life Nf (number of fracture repetitions) until the beam member 2 (steel member) reaches fracture. Specifically, the fracture life Nf of the beam member 2 is calculated using the above-mentioned formula 2 stored in the storage unit 14 in advance.

[0057] Note that the plastic strain rate μ of the performance curve used in step S13 as described above is based on the fully plastic load and has a different reference from the yield plastic strain rate μy calculated in step S12. Therefore, the yield plastic strain rate μy calculated in step S12 is pre-converted using the conversion coefficient stored in the storage unit 14 in advance.

[0058] In the subsequent step S14, the evaluation unit 13 evaluates the influence received by the beam member 2 (steel member) during an earthquake based on the fracture life Nf (number of fracture repetitions) calculated by the calculation unit 12 and the number of swaying times n of the floor where the beam member 2 is provided.

[0059] Specifically, the damage degree D of the beam member 2 is obtained by dividing the number of swaying times n by the fracture life Nf. When the damage degree D does not exceed 1, it is determined that the beam member 2 is sound. When the damage degree D is 1 or more, it is determined that the beam member 2 is not sound.

[0060] The result evaluated by the evaluation unit 13 in this way is displayed on the display unit 30 and stored in the storage unit 14. Note that the evaluation based on the damage degree D may not only indicate whether it is sound or not, but also indicate the damage level according to the magnitude of the value of the damage degree D.

[0061] In step S14, when the evaluation unit 13 evaluates the damage degree D, the number of shaking times n during an earthquake in the floor of the steel-frame building where the beam member 2 is provided 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 degree D, and may be based on the remaining performance (1 - D) or the margin (1 - D) / D.

[0062] In the subsequent step S15, the evaluation unit 13 evaluates the influence that the beam member 2 (steel member) has received during the earthquake based on the yield plastic strain rate μy calculated in step S12 and the allowable plastic strain rate μa preset for each beam member 2.

[0063] Specifically, the yield plastic strain rate μy and the allowable plastic strain rate μa are compared. When the yield plastic strain rate μy does not exceed the allowable plastic strain rate μa, it is determined that the beam member 2 is sound. When the yield plastic strain rate μy is equal to or greater than the allowable plastic strain rate μa, it is determined that the beam member 2 is not sound.

[0064] The result evaluated by the evaluation unit 13 in this way is displayed on the display unit 30 and stored in the storage unit 14. Note that the evaluation based on the yield plastic strain rate μy and the allowable plastic strain rate μa may indicate the damage level according to the ratio of the yield plastic strain rate μy to the allowable plastic strain rate μa, rather than just whether it is sound or not.

[0065] The allowable plastic strain rate μa used for evaluation in step S15 may be input via the input unit 20 or may be stored in the storage unit 14 in advance. Note that when the allowable plastic strain rate μa is based on the full plastic load, the yield plastic strain rate μy calculated in step S12 is pre-converted by a conversion coefficient pre-stored in the storage unit 14.

[0066] Through these steps, the earthquake impact evaluation method performed by the earthquake impact evaluation device 10 is completed, and the influence that the beam member 2 has received during the earthquake is evaluated.

[0067] According to the above embodiments, the following effects are achieved.

[0068] In the seismic impact evaluation device 10, based on the plasticized range Ly acquired by the acquisition unit 11, the yield plastic strain rate μy of the beam member 2 (steel member) during an earthquake is calculated by the calculation unit 12, and based on the calculated yield plastic strain rate μy, the damage degree D indicating the impact received by the beam member 2 during the earthquake and the ratio of the yield plastic strain rate μy to the allowable plastic strain rate μa are evaluated by the evaluation unit 13.

[0069] In this way, even if the measurement of the deformation or the like of the beam member 2 (steel member) that occurred during the earthquake is not performed in real time, by calculating how much the beam member 2 was deformed during the earthquake based on the plasticized range Ly acquired after the earthquake, the impact received by the beam member 2 during the earthquake can be easily evaluated after the earthquake.

[0070] Note that the above embodiment assumes a case where a repeated load acts on the beam member 2 (steel member) due to an earthquake, for example, a case where the earthquake is a trench-type earthquake. On the other hand, when the beam member 2 (steel member) is largely displaced by a single vibration as in the case of a direct underground earthquake, it is possible to evaluate the impact received by the beam member 2 during the earthquake after the earthquake by the following method.

[0071] Generally, in a direct underground earthquake, unlike a trench-type earthquake, a large displacement occurs in the beam member 2 (steel member) due to a single vibration. Therefore, based on the results of the monotonic loading test, it is possible to estimate how much damage the beam member 2 received during the earthquake.

[0072] Here, since the bending moment M, the yield moment My, and the magnitude of the plasticized range Ly are in the relationship of the above formula (1), when the vertical axis of the graph in FIG. 2 showing the results of the monotonic loading test is converted using the above formula (1) and the beam depth H of the beam member 2, the graph shown in FIG. 10 is obtained. In FIG. 10, the horizontal axis is converted to the yield plastic strain rate μy calculated with the yield deformation θy as the denominator.

[0073] From the graph shown in Fig. 10, it is possible to estimate how much the plasticized region (Ly / H) will be when the beam member 2 is displaced at one time with a yield plastic strain rate μy of a certain degree.

[0074] In other words, if the plasticized range Ly of the beam member 2 after the direct underground earthquake is grasped by various methods as described above, and the size of the beam depth H of the beam member 2 is grasped from the drawing or the like, from the relational expression B shown in Fig. 11 obtained by interchanging the vertical axis and the horizontal axis of the graph in Fig. 10, it is possible to estimate the yield plastic strain rate μy at the time of earthquake indicating how much the beam member 2 was deformed at the maximum during the earthquake. Note that the relational expression B is an approximate curve obtained from a graph obtained by interchanging the vertical axis and the horizontal axis of the graph in Fig. 10.

[0075] By comparing the yield plastic strain rate μy calculated in this way with the allowable plastic strain rate μa preset for each beam member 2, it is possible to evaluate the influence received by the beam member 2 (steel member) in the direct underground earthquake.

[0076] Note that the graph shown in Fig. 11 has the same vertical axis and horizontal axis as the graph shown in Fig. 6. The graph shown in Fig. 6 shows the yield plastic strain rate μy at a constant amplitude, that is, the yield plastic strain rate μy in a state close to the shaking generated by the subduction zone earthquake, while the graph shown in Fig. 11 shows the yield plastic strain rate μy during monotonic loading, that is, the yield plastic strain rate μy in a state close to the shaking generated by the direct underground earthquake.

[0077] Therefore, in the case of a composite earthquake of the subduction zone type and the direct underground type, based on the yield plastic strain rate μy calculated by adding the yield plastic strain rate μy at the time of earthquake estimated from the relational expression A and the yield plastic strain rate μy at the time of earthquake estimated from the relational expression B at an arbitrary ratio, the influence received by the beam member 2 (steel member) in the earthquake may be evaluated.

[0078] As described above, the embodiments of the present invention have been described. However, the above embodiments merely show a part 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.

Explanation of Reference Numerals

[0079] 10··· Earthquake impact assessment device 2··· Beam member (steel member) 11··· Acquisition unit 12··· Calculation unit 13··· Evaluation unit

Claims

1. An earthquake impact evaluation device for evaluating the impact on steel members constituting a steel frame building due to an earthquake, an acquisition unit that acquires the range of the plasticized region of the steel member, a calculation unit that calculates the plastic strain rate of the steel member during an earthquake based on the range of the plasticized region, and an evaluation unit that evaluates the impact on the steel member due to the earthquake based on the plastic strain rate. Earthquake impact evaluation device.

2. The calculation unit calculates the plastic strain rate using a relational expression between the range of the plasticized region and the plastic strain rate at a constant amplitude, which is established in advance based on the change in the range of the plasticized region with respect to the number of repetitions. The earthquake impact evaluation device according to Claim 1.

3. The acquisition unit further acquires the number of vibrations of the steel frame building during an earthquake, the calculation unit calculates the number of fracture repetitions until the steel member fractures based on the plastic strain rate, and the evaluation unit evaluates the impact on the steel member due to the earthquake based on the number of fracture repetitions and the number of vibrations. The earthquake impact evaluation device according to Claim 1 or 2.

4. The acquisition unit further acquires the allowable plastic strain rate of the steel member, and the evaluation unit evaluates the impact on the steel member due to the earthquake based on the plastic strain rate and the allowable plastic strain rate. The earthquake impact evaluation device according to Claim 1 or 2.

5. An earthquake impact evaluation method for evaluating the impact on steel members constituting a steel frame building due to an earthquake, including the steps of: acquiring the range of the plasticized region of the steel member, calculating the plastic strain rate of the steel member during an earthquake based on the range of the plasticized region, and evaluating the impact on the steel member due to the earthquake based on the plastic strain rate. Earthquake impact evaluation method.

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