JP2003155776A - Vibration resistant design processing method taking earthquake risk as index, vibration resistant design processor and program for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform vibration resistant design at minimum cost through evaluation on damage due to an earthquake. SOLUTION: A target earthquake risk is set by a target earthquake risk setting means 10, and the degree of damage, vibration resistant performance and the restriction conditions on the cost of each part of a building as a design object are analyzed by various types of analyzing means. The design specifications for minimizing the cost within a range meeting the target earthquake risk are computed by a cost optimizing and analyzing means 15. Thus, vibration resistant design taking an earthquake risk as an index is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for performing seismic design of a building while taking the construction cost into consideration by using an earthquake loss amount (earthquake risk) as an index.

[0002]

2. Description of the Related Art Conventionally, as a system for evaluating damage caused by an earthquake, an earthquake damage evaluation system (Japanese Patent Laid-Open No. 11-175)
623). This is to estimate the earthquake motion strength expected in the construction site from past earthquake occurrence data and active faults, calculate the damage rate of the building due to ground liquefaction and ground vibration, and evaluate the damage due to the earthquake. It is a system that evaluates the amount of insurance paid for each region. However, until now, no technology for seismic design has been found based on the evaluation of damage caused by an earthquake.

In the conventional seismic design method, the center of design is placed only on the specification of initials and the determination of price.
There was little awareness of the costs that occur over the years, such as the cost of repairing damage to buildings due to the earthquake. In addition, although it is considered that the actual regional difference in earthquake risk is large, the regional difference is small under the current Building Standards Law due to engineering judgment, and the loss due to earthquake (earthquake risk) is rarely reflected in the design. It was As a result, the relationship between seismic performance (design) and seismic risk was ambiguous, and the business owner's incentive for earthquake resistance did not work.

[0004]

In the conventional technology, there is already a method of calculating the earthquake risk from the design document, but there is no method of determining the design specification from the earthquake risk, and the intuition of the designer and the trial and error. I had to rely on. In addition, there are an unlimited number of design specifications that specify earthquake risk, but it was difficult to find a specification with the lowest cost.

An object of the present invention is to solve the above-mentioned problems and to carry out seismic design which minimizes the cost from the evaluation of damage caused by an earthquake.

[0006]

[Means for Solving the Problems] In order to solve the above problems, the present invention is characterized in that earthquake risk is considered as an index of seismic performance, and seismic design directed to seismic risk is performed. That is, the present invention is characterized by having means for automatically designing a target earthquake risk by designating the constraint condition of each part by designating the target earthquake risk. Also,
There are innumerable design specifications for the same earthquake risk, but the feature is that the design specification with the lowest cost is automatically calculated.

The major difference between the present invention and the prior art is that
Designing for earthquake risk, and designing for minimum cost within the specified earthquake loss amount (earthquake risk).

FIG. 1 is a diagram for explaining the outline of the present invention in comparison with the prior art. The present invention first sets a target earthquake risk, as shown in FIG. Next, the constraint conditions regarding the degree of damage, seismic performance, and cost of each part of the building to be designed are analyzed, and the design specifications that minimize the cost within the range that satisfies the target earthquake risk are calculated from the analyzed constraint conditions.

In the prior art design, for example, FIG.
As shown in (B), the construction cost is first set, and the design that satisfies the cost setting value is performed. After that, evaluate the seismic risk, inspect whether it complies with the Building Standards Law, and redesign if it does not. If the target earthquake risk cannot be met within the set cost, the construction cost is reset.

According to the design according to the prior art, the design satisfying the target earthquake risk is not always optimum in cost, but the present invention enables the design with the minimum (optimum) cost. Further, according to the present invention, it becomes possible to make rational setting of seismic performance.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing a configuration example of the seismic design system according to the present invention. Seismic design processor 1
A target earthquake risk setting means 10, an earthquake risk analysis means 11, a damage degree evaluation analysis means 12, a grade damage degree analysis means 13, a cost grade analysis means 14, which is a device including a CPU and a memory, and which is realized by a software program. Cost optimization analysis means 15, design specifications
A member selecting means 16 and a database 17 in which various data for design are stored are provided.

This system is used to record information such as use, useful life, earthquake environment, cost, etc. in the database 17 such as historical seismic data, active fault data, seismic structure, damage data, seismic motion data, analysis data, It is a system that uses various data such as design data and estimate data to analyze and determine the design specifications that minimize the cost for the set target earthquake risk. The details of the processing performed by each unit shown in FIG. 2 will be sequentially described below.

[Setting of Target Earthquake Risk] The target earthquake risk setting means 10 sets a target earthquake risk in seismic design. Figure 3 shows an example of how to set the target earthquake risk. The setting method is (1) direct setting, (2)
There are various methods such as setting based on the principle of minimizing the total cost and (3) quantification based on engineering judgment. The target seismic risk setting means 10 inputs the numerical information of the seismic risk according to the setting method selected by the user, and sets the seismic risk as a target for subsequent seismic design.

(1) Directly set earthquake motion (reproduction) The probability Prob of encountering the earthquake motion during its useful life can be obtained from the reproduction period required for the expected value. In the following equation, T is the earthquake motion reproduction period and N is the useful life.

Prob = 1- (1-1 / T) ^N (Equation 1) For example, a building with a useful life of 50 years has a reproduction period of 5
When an earthquake of 00 years (a large earthquake that occurs about once every 500 years) is received, the probability of encounter is about 9.5%. On the contrary, when designing for a large earthquake with an encounter probability of about 5%, it is necessary to calculate backward and design for an earthquake for a return period of about 975 years.

The encounter probability and the target reproduction period also change according to the service life. By setting the estimated amount of damage for the expected earthquake motion intensity during the calculated return period,
Set the target earthquake risk.

PML (Pro is an index of earthquake risk
If it is quantified by bable maximum loss, set the seismic risk (ratio of repair cost to construction cost) to the earthquake motion with a recurrence period of 475%. The seismic risk is set as a percentage for any index using the above formula.

(2) Setting by the principle of minimizing the total cost FIG. 4 is a diagram for explaining the principle of minimizing the total cost. The total cost minimization principle is a method of finding the optimum safety level by using the economic value (cost) as a scale. The total cost is expressed by the following formula.

C _t = C _i + P _f C _F where C _{t is the} total cost, C _{i is the} initial construction cost, P _{f is the} damage occurrence probability, and C _F is the damage amount. The optimum safety level is the part where C _t is minimum.

What is desired here is the earthquake risk P _f C _F / C _i , but since it is the initial setting of the target earthquake risk, C _i and P _f C calculated empirically and simply _F
We asked the C _t from, earthquake at the optimum level risk P _f C _F
Calculate / C _i .

(3) Quantification by engineering judgment It is considered that most buildings except special uses are designed according to the minimum standard of the Building Standard Law. From this, it is considered possible to estimate the probability of damage to buildings in Japan by examining past earthquake damage conditions. In addition, the minimum seismic motion level of the Building Standard Law is assumed to have a recurrence period of about 500 years. On the other hand, the useful life of the existing building is considered to be about 50 years, considering the values such as material guarantee.

From the above, it can be considered that a general building is guaranteed to be safe against earthquake motion with a recurrence period of approximately 500 years (a person's name is secured, but the building suffers great damage). . According to the calculation of (Equation 1), the probability of encountering a large earthquake during its service life is 9.5% (≈10%).
it is conceivable that.

Numeralization by engineering judgment is to set a numerical value in consultation with the business owner based on the above-mentioned encounter probability and reproduction period.

[Earthquake risk analysis] Earthquake risk analysis means 1
In 1), the earthquake ground motion estimated at the building construction site is evaluated, and the seismic hazard curve is calculated. FIG. 5 shows an earthquake risk analysis processing flowchart by the earthquake risk analysis means 11.

First, in step S11, position information of a building construction point is input. In step S12, the seismic activity area centered on the input building construction point is calculated based on the historical seismic data, active fault data, seismic structure, etc. stored in the database 17.

FIG. 6 shows an example of historical seismic data. The size of the circle represents the size of the earthquake. For the calculation of the seismic activity area, the hypocenter and scale data of the past damaging earthquakes as shown in Fig. 6 are used. Moreover, active fault data as shown in FIG. 7 is also used. Of course, these data are digitized and held in the database 17 together with the position information.

In step S13, an earthquake occurrence model is set based on the calculation result of the seismic activity area, and the subsequent step S1
In Section 4, the distance attenuation from each predicted earthquake occurrence point to the building construction point is calculated based on the earthquake occurrence model. In step S15, the amplification characteristic of the surface ground is calculated based on the surface ground (ground geology) data obtained from the database 17 as shown in FIG. The surface geological data shown in FIG. 8 is an example, and the data may be any data as long as the amplification characteristics of the surface ground can be calculated, and the data format is not limited to that shown in FIG. In step S16, an earthquake hazard is calculated from the above calculation results, and an earthquake hazard curve and an earthquake hazard map are output.

FIG. 9 shows an example of the calculated earthquake hazard curve. The seismic hazard curve in Fig. 9 shows the seismic intensity (PG
V) indicates the probability of seismic motion year excess according to V).

[Building Damage Evaluation] Damage evaluation analysis means 1
2 is based on past earthquake damage data and analytical examination
Assess the degree of damage to each part of the building against the seismic intensity.

From the past earthquake damage data, a damage degree curve is calculated by regressing each scatter diagram to an elementary function for each item such as the year of completion of construction, structural type, basic form, equipment and finish. FIG. 10 shows an example of the damage level curve calculated by the damage level evaluation / analysis means 12. The vertical axis represents the degree of damage and the horizontal axis represents the seismic intensity. Black circles represent earthquake damage data from past earthquakes.

As an analytical method, seismic response analysis of an analytical model having various structural parameters with various seismic motions observed in the past as inputs is performed, and the response values (displacement, acceleration, etc.) obtained as a result are scattered. The damage curve is calculated by returning to the elementary function from the figure.

FIG. 11 shows a flow chart of the building damage degree evaluation processing by the damage degree evaluation analysis means 12.

First, in step S21, a multi-mass vibration model of a building is input. Next, in step S22, the analysis maximum speed V _max of the shaking due to the earthquake and the speed increment ΔV are set. In step S23, each building component is grouped. As an example of grouping, grouping in the height direction (floor direction) can be considered. The number of groups is N. By evaluating the seismic performance of each group, it is possible to evaluate the damage level of the building with high accuracy. Here, the loop variable of the process for the N groups is set to i, and the loop variable for the M pieces of seismic waveform data is set to k, initialized to 0, and the following process is repeated.

In steps S24 to S33, i is incremented by 1 and repeated until i becomes N or more. In steps S25 to S32, the processing target speed V _j is increased by ΔV, and the processing is repeated until V _j becomes V _max or more. Further, in steps S26 to S29, k is 1
The process is repeated for the k-th seismic motion waveform while incrementing each.

In step S27, the maximum velocity of the k-th earthquake motion waveform is normalized to V _j . In step S28,
Calculate the response to the seismic motion waveform normalized to V _j .
After the response calculation is performed on the M pieces of seismic wave waveform data, the process proceeds to step S30, and a representative distribution function expressing the variation of the M pieces of response values of the constituent element (eg, representative floor) that represents the i-th group Calculate parameters (eg mean, standard deviation, etc.). In step S31, the damage probability for the maximum velocity V _j of the i-th group is calculated. The above process is repeated for each group i up to the analysis maximum speed V _max .

FIG. 12 shows seismic performance data of the building components used in step S31. For each group, input parameters include parameters that represent the judgment index of strength, probability distribution, and distribution of variation. The judgment index (evaluation scale) of proof stress is the interlayer deformation angle of each layer for the frame and finish, and the ground acceleration for the foundation.

FIG. 13 shows the damage degree curve of each group calculated in step S31. The damage probability (degree of damage) increases as the strength of the earthquake motion increases. However, the rate of increase is different for each group such as the number of floors, finish, and equipment. FIG. 14 shows the damage probability density function of each group similarly calculated in step S31.

[Analysis of Grade Damage] Generally, it is considered that the seismic resistance is improved by increasing the cross-sectional size and quantity.
Recently, various devices have been developed to improve seismic performance from various angles. Grade damage degree analysis means 1
In grade damage degree analysis according to 3, the relationship between seismic performance (grade) and damage degree is evaluated.

As described above, it is considered that many domestic buildings are designed according to the minimum standards shown in the Building Standards Law. Conversely, domestic buildings are considered to have almost the same seismic performance. Based on this seismic performance,
We will build an analysis model that assumes a design of a higher grade than that design, and perform many seismic response analyzes in the same way as the analytical method for building damage assessment described in the previous section. as a result,
The relationship between grade and degree of damage can be obtained.

FIG. 15 shows an example of the result of grade damage degree analysis. The vertical axis represents the degree of damage and the horizontal axis represents the grade, and the results of analysis of the degree of damage according to each grade are indicated by small circles. The grade damage curve is a numerical representation of the grade and damage gradient.

[Cost Grade Analysis] When the grade is increased, the cross-sectional dimension and quantity increase, so that the cost generally rises. Recently, various devices have been developed not only to increase the cross-sectional size and quantity, but also to increase seismic resistance. However, the seismic isolation structure has a different damage mechanism from the seismic resistant structure with many examples in the past,
It is desirable to handle them separately.

In the cost grade analysis by the cost grade analysis means 14, various grades are set for tentative design and the rate of increase based on the cost of the current Building Standard Act is evaluated.

FIG. 16 shows an example of the result of the cost grade analysis. The vertical axis represents the cost and the horizontal axis represents the grade. The correspondence between the grade calculated for each temporary design data and the cost
It is indicated by a small circle. The grade cost curve is a numerical representation of the grade and cost gradients.

[Cost Optimization Analysis] FIG. 17 shows a flowchart of the cost optimization analysis process by the cost optimization analysis means 15. The cost optimization analysis unit 15 determines the design condition that satisfies the set target earthquake risk and is the minimum cost from the analysis results by the earthquake risk analysis unit 11 to the cost grade analysis unit 14.

Therefore, in step S41, the initial cost for each part regarding the foundation, structure, equipment and finishing is set. Here, the cost of the temporary design data is input and set. In step S42, an initial value of the degree of damage (breakdown probability) is set for each part. Since it is the initial value, any value is acceptable, but it is desirable to set the value with reference to the damage level of the building designed with the minimum standard of seismic performance specified in the Building Standards Act.

Next, in step S43, FIG.
In the grade damage degree curve for each part as shown in Fig. 5, the change in grade is calculated from the difference between the initial value of damage degree and the reference value of a certain damage degree. In the following step S44, based on the grade cost curve as shown in FIG. 17D, from the change in grade calculated in step S43,
Calculate the change in cost, that is, the standard value of the cost of each part. In step S45, the cost ratio for the foundation, structure, equipment and finishing is calculated from the change in cost of each part.

Next, in step S46, event tree analysis is performed, and in step S47, the earthquake risk is calculated from the analysis result of the event tree. In the event tree analysis, the damage scenario (event) of each part is assumed based on the damage degree evaluation of each part, and the occurrence probability of each event is calculated. The earthquake risk of the event is calculated by multiplying the damage amount of the damage scenario by the occurrence probability. The seismic risk of all events is added together to obtain the seismic risk of the entire building.

FIG. 18 shows an example of the analysis result of the event tree analysis and the calculation result of the earthquake risk. The foundation is categorized as damageless, moderate, and severely damaged, the structure is categorized as damageless, small, moderate, and severely damaged, and the finishing and equipment are categorized as damageless and damageless. obtains the respective probability of occurrence, and the occurrence probability Pf _i of all of these combinations, to calculate the amount of damage C _i. Here, the damage amount C _i is shown as a relative amount with the maximum damage amount being 1.
All i that sum is multiplied by the Pf _i and C _i for is a whole building earthquake risk (expected loss), here, is set to be 5% target PML this. That is, FIG. 18 shows an example of the seismic risk when the target seismic risk is set so that the seismic risk (ratio of the repair cost to the construction cost) for the earthquake motion of the reproduction period 475 is 5%.

In step S48, the destruction probability of the part is optimized at the minimum cost. Specifically, step S
The damage probability of each part is changed on condition that the earthquake risk calculated in 47 is close to the target earthquake risk (the grade change and the cost change due to the change are automatically performed each time). As an optimization method, a quasi-Newton method or a conjugate gradient method can be used. As a conceptual process, using the current standard value of the grade of each part as a new initial value, steps S43 to S48 are repeated, and the grade and cost of each part with the minimum cost within the range satisfying the target earthquake risk are determined. A process for searching will be performed (step S49).

[Selection of Design Specification and Member Satisfying Failure Probability] In the design specification / member selection means 16, the cost optimization analysis means 15 calculates the optimum value of the failure probability (damage degree) for each part. So, grade damage degree analysis means 1
The temporary design corresponding to the optimum value of the failure probability calculated by the cost optimization analysis means 15 is set as the design specification from among the large number of temporary designs carried out in 3, and the members suitable for the design specification are selected. And output the result.

The above means can be realized by a computer and a software program installed and executed in the computer. The program is a computer-readable portable medium memory,
It can be stored in an appropriate recording medium such as a semiconductor memory or a hard disk.

[0052]

As described above, according to the present invention, the seismic performance is expressed by a value (ratio) called an earthquake risk, so that not only the setting of the seismic performance is rational but Motivation for determining seismic performance can be increased. In addition, the cost is minimized against the target earthquake risk, so the cost can be reduced while maintaining the seismic performance.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the outline of the present invention.

FIG. 2 is a diagram showing a configuration example of a seismic design system according to the present invention.

FIG. 3 is a diagram showing an example of a method of setting a target earthquake risk.

FIG. 4 is a diagram for explaining the principle of minimizing the total cost.

FIG. 5 is an earthquake risk analysis processing flowchart.

FIG. 6 is a diagram showing an example of historical earthquake data (source and scale data of damaging earthquakes that occurred in the past).

FIG. 7 is a diagram showing an example of active tomographic data.

FIG. 8 is a diagram showing an example of surface layer ground data.

FIG. 9 is a diagram showing an example of an earthquake hazard curve.

FIG. 10 is a diagram showing an example of a damage degree curve.

FIG. 11 is a flowchart of a building damage degree evaluation process.

FIG. 12 is a diagram showing an example of seismic performance data.

FIG. 13 is a diagram showing an example of a damage degree curve of each group.

FIG. 14 is a diagram showing an example of a damage probability density function of each group.

FIG. 15 is a diagram showing an example of a result of grade damage degree analysis.

FIG. 16 is a diagram showing an example of a result of cost grade analysis.

FIG. 17 is a cost optimization analysis processing flowchart.

FIG. 18 is a diagram showing an example of the analysis result of the event tree analysis and the calculation result of the earthquake risk.

[Explanation of symbols]

1 Seismic design processor 10 Target earthquake risk setting means 11 Earthquake risk analysis means 12 Damage evaluation analysis means 13 Grade damage analysis means 14 Cost grade analysis means 15 Cost optimization analysis means 16 Design specifications / member selection means 17 Database

Claims (3)

[Claims] 1. A method of designing a building by a computer, the process of setting a target earthquake risk, and the process of analyzing constraint conditions regarding damage degree, seismic performance, and cost of each part of the building to be designed. And a seismic design processing method using seismic risk as an index, which comprises a step of calculating a design specification having a minimum cost within a range satisfying a target seismic risk from the analyzed constraint conditions. 2. A device for designing a building by a computer, means for setting a target earthquake risk, means for analyzing seismic risk at a construction point, and damage degree of each part of the building to seismic intensity. To evaluate the relationship between the seismic performance and damage of each part of the building, a means to analyze the relationship between the seismic performance and cost of each part of the building, and From the relationship between seismic performance and damage and the relationship between seismic performance and cost, calculate the change in cost when the seismic performance of each part of the building is changed within the range that satisfies the target earthquake risk set above, and calculate the minimum A seismic design processing apparatus using seismic risk as an index, comprising means for optimizing a failure probability of each part according to cost and means for outputting a design specification based on the optimization result. 3. A program for designing a building by a computer, wherein processing for setting a target seismic risk and analysis of constraints regarding damage degree, seismic performance, and cost of each part of the building to be designed A seismic design processing program using a seismic risk as an index for causing a computer to execute the processing for executing the processing and the processing for calculating the design specification with the minimum cost within the range satisfying the target seismic risk from the analyzed constraint conditions.