JP4471104B2 - Building evaluation system and building evaluation method - Google Patents

Description

  The present invention relates to a building evaluation system and a building evaluation method, and relates to a building evaluation system and a building evaluation method that can objectively grasp the cost-effectiveness of earthquake-proof repair for each earthquake-proof repair plan of each existing building.

  The technique described in patent document 1 is known for the conventional building evaluation system. A conventional building evaluation system stores and stores numerical seismic performance data for each item of the main structure, non-structure, and building equipment for each existing building for an existing building group; A means for storing and storing numerically weighted data with relative weighting in accordance with the use and usage of the existing building as to the importance of the seismic performance of each item at the time of an earthquake; Input means for inputting new or modified data, means for storing and storing the weighted data, input means for inputting these new or modified data, and numerical values of the weighted data and seismic performance data for each item. Means for obtaining an evaluation score, averaging the evaluation scores, and obtaining a comprehensive evaluation score for the seismic performance of the existing building, and existing buildings sorted in the order of the comprehensive evaluation score And output means for outputting the refurbishment priority in the list data, characterized by comprising display means for displaying the output data.

  In other words, in the conventional building evaluation system, for multiple existing buildings, the overall evaluation score of the existing building's seismic performance is calculated individually from the seismic performance of each item of the main structure, non-structure and building equipment. The Then, a list is output in ascending order of the overall evaluation score, and it is set as a modification priority. Also, the importance factor depending on the use of the existing building is taken into account.

  Here, when performing seismic retrofit within a limited budget for a plurality of existing buildings, it is necessary to evaluate the priority of seismic retrofit while considering cost effectiveness and importance. However, in the conventional building evaluation system, attention is paid to the seismic performance of existing buildings, but the probability of earthquake occurrence (earthquake risk) is not considered. For this reason, there is a problem that the cost effectiveness of seismic retrofit cannot be objectively grasped.

JP-A-10-142112

  Therefore, the present invention has been made in view of the above, and provides a building evaluation system and a building evaluation method capable of objectively grasping the cost-effectiveness of earthquake-proof repair for each earthquake-proof repair plan of each existing building The purpose is to do.

  In order to achieve the above object, a building evaluation system according to the present invention is a building evaluation system that evaluates the priority of earthquake-resistant repairs on a plurality of existing buildings. Based on the relationship between the structural seismic index, the means for calculating the earthquake risk of the existing building for the seismic retrofit plan for each existing building and the internal rate of return for the seismic retrofit plan for each existing building based on the seismic risk And means for determining the priority of earthquake-resistant repairs on existing buildings based on the internal rate of return.

  In this building evaluation system, for each existing building, the earthquake risk of the existing building for the seismic retrofit plan is calculated, and the internal rate of return for the seismic retrofit plan is calculated based on this seismic risk. And since the priority of the earthquake-proof repair concerning an existing building is determined based on this internal rate of return, there exists an advantage by which the cost-effectiveness of an earthquake-proof repair is grasped objectively for every earthquake-proof repair plan.

  Further, in the building evaluation system according to the present invention, in calculating the internal rate of return, changes in the rent income and the sale price of the existing building due to the seismic retrofit are taken into consideration.

  This building evaluation system has the advantage of more objectively grasping the cost-effectiveness of seismic retrofitting because the rent income and sales price of existing buildings due to seismic retrofit are taken into account when calculating the internal rate of return. is there.

  In the building evaluation system according to the present invention, the change in the rent income and the sale price of the existing building due to the earthquake-resistant repair is calculated in consideration of the timing of the earthquake-resistant repair.

  In this building evaluation system, changes in rent income and sales prices of existing buildings due to seismic retrofit are calculated taking into account the timing of seismic retrofit, so the cost-effectiveness of seismic retrofit can be grasped more objectively. There are advantages.

  In addition, in the building evaluation method according to the present invention, in the building evaluation method for evaluating the priority of the earthquake-proof repairs for a plurality of existing buildings, the relationship between the earthquake-proof repair costs standardized by the replacement cost and the structural earthquake resistance index. Calculating the earthquake risk of the existing building for the earthquake-proof repair plan for each existing building, and calculating the internal rate of return for the earthquake-proof repair plan for each existing building based on the earthquake risk, and And a step of determining a priority order of earthquake-proof repairs on the existing building based on the internal rate of return.

  In the building evaluation system according to the present invention, the earthquake risk of the existing building with respect to the seismic retrofit plan is calculated for each existing building, and the internal rate of return for the seismic retrofit plan is calculated based on the seismic risk. And since the priority of the earthquake-proof repair concerning an existing building is determined based on this internal rate of return, there exists an advantage by which the cost-effectiveness of an earthquake-proof repair is grasped objectively for every earthquake-proof repair plan.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements of the embodiments described below include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIGS. 1-3 is a hardware block diagram (FIG. 1), a functional block diagram (FIG. 2), and a flowchart (FIG. 3) which show the building evaluation system concerning Example 1 of this invention. FIG. 4 and FIG. 5 are explanatory diagrams showing a cash flow stream before and after the seismic retrofit and changes thereof. FIG. 6 is a table showing an example of calculating the internal rate of return for each seismic retrofit plan. FIG. 7 and FIG. 8 are explanatory diagrams showing a cash flow stream before and after the seismic retrofit and changes thereof when the seismic retrofit time is taken into consideration. FIG. 9 is an explanatory diagram showing a cash flow stream that occurs periodically. FIG. 10 is a graph showing the relationship between the seismic retrofit cost standardized by the replacement procurement price and the structural seismic index. FIG. 11 is a graph showing the relationship between the seismic retrofit cost standardized by the replacement price and the earthquake risk of a certain year.

[Internal rate of return]
In the field of financial engineering, an internal rate of return (IRR) is used as an indicator of cost effectiveness. First, consider a case _where there is a negative flow x ₀ at the present time and a positive flow x ₁ , x ₂ ,. reference). In FIG. 9, the horizontal axis represents time and the vertical axis represents the positive / negative and magnitude of the flow.

When such a cash flow stream x (x ₀ , x ₁ , x ₂ ,..., X _n ) and a discount rate r are given, the net present value NPV (Net Present) of the cash flow stream x Value) is given by the following formula using the DCF method (Discounted Cash Flow Analysis).

Here, 1 / (1 + r) ^k (k: number of years) is called a compound interest cost rate, and is a coefficient for rebating the future value to the current value. In addition, the discount rate r at which the net present value NPV = 0 of the cash flow stream x is a discount rate r inherent in the structure of the cash flow stream x, and thus is particularly called an internal rate of return IRR.

If the fixed positive periodic flow c (x ₁ , x ₂ ,..., X _n ) continues forever, the present value PV (Present of this cash flow stream x is used using the discount rate r. Value) is calculated by c / r. When the initial investment amount (negative flow) x ₀ is added to the cash flow stream x, the net present value NPV is calculated by x ₀ + c / r. When the net present value NPV = 0, the internal rate of return IRR = −c / x ₀ .

  By the way, in the direct capitalization method, which is one of the asset value evaluation methods for existing buildings (real estate), net income (positive) is calculated by subtracting administrative expenses, taxes and other expenses from income such as rent per year. Flow) Based on c and capitalization yield R, the asset value of an existing building is calculated as c / R.

The formula x ₀ = −c / IRR (from IRR = −c / x ₀ ) related to the asset value c / R of the existing building and the internal rate of return IRR is similar, but the difference is noted. There is a need. That is, in the former, the asset value c / R of an existing building is evaluated by specifying the net revenue c per year and the capitalization yield R. On the other hand, in the latter case, the internal rate of return IRR of the cash flow stream x is calculated by designating the initial investment amount x ₀ and the subsequent net income c. The higher the internal rate of return IRR, the higher the cost effectiveness. When the net income c is equal, the asset value c / R of the existing building is higher as the capitalization yield R is smaller.

[Building evaluation system]
The building evaluation system 1 includes a control device 2, an input device 3, an output device 4, and a data file (database) 5, and is configured by, for example, a PC (Personal Computer) (see FIG. 1). The control device 2 includes a CPU (central processing unit) 21, a ROM (read-only memory) 22, a RAM (random-access memory) 23, and an interface circuit 24. The control device 2 has a predetermined evaluation function (see FIG. 2) and executes evaluation of the existing building based on various data and input information of the existing building. The input device 3 includes, for example, a keyboard and a mouse, and is connected to the control device 2 via the interface circuit 24. From the input device 3, information and commands necessary for evaluating an existing building are input to the control device 2. The output device 4 includes, for example, a monitor, and is connected to the control device 2 via the interface circuit 24. This output device 4 displays an information input screen and an evaluation result of an existing building (priority order of earthquake-resistant repair, etc.). The data file (database) 5 is an external storage device, for example, and is connected to the control device 2 via the interface circuit 24. The data file 5 stores active fault data, historical earthquake data, ground data, existing building fragility data, and the like.

  Moreover, this building evaluation system 1 has the 1st evaluation part 2a-the 5th evaluation part 2e (refer FIG. 2). These evaluation units 2a to 2e are stored in the ROM 22 as programs, for example, and are read into the RAM 23 and executed by the control device 2 when the system is operating. The first evaluation unit 2a is a means for evaluating (calculating) the earthquake risk (direct damage and indirect damage) of an existing building. The second evaluation unit 2b is a means for evaluating (setting) the relationship between the seismic repair cost standardized by the replacement procurement price and the structural seismic index. The 3rd evaluation part 2c is a means to evaluate (calculate) the earthquake risk of the existing building with respect to each seismic retrofit plan. The fourth evaluation unit 2d is a means for evaluating (calculating) the internal rate of return IRR for each seismic retrofit plan. The 5th evaluation part 2e is a means which evaluates (decides) the priority of the earthquake-proof repair concerning an existing building based on the internal rate of return IRR.

[Building evaluation method]
In this building evaluation system 1, the priority of the earthquake-proof repair concerning an existing building is evaluated as follows (refer FIG. 3). First, the fragility data (structure specifications and importance coefficient) of the target existing building is set (ST1). Specifically, for each existing building, structural type, number of floors, structural seismic index (Is value), presence or absence of structural vulnerability factors such as piloti and eccentricity, aged deterioration status, location (latitude and longitude), In addition, ground conditions (N value and ground columnar diagram by boring survey, or P wave velocity and S wave velocity structure by PS logging) are set.

  Here, the importance coefficient of an existing building is a coefficient set in order to consider relative importance.

  Next, based on these fragility data, active fault data, historical earthquake data, and ground data, an existing building earthquake risk assessment is performed (ST2). The current seismic risk assessment is grasped as a cash flow stream x, and the annual expected value or the seismic risk for a certain year excess probability is calculated for each existing building (Figure 4 (a) and (See FIG. 5 (a)).

  Next, the relationship between the seismic retrofit cost and the structural seismic index standardized at the replacement cost is set for each existing building (ST3). And the earthquake risk evaluation of the existing building after earthquake-proof repair is performed (ST4). The seismic risk assessment after seismic retrofit is grasped as a cash flow stream x corresponding to the current seismic risk assessment, and the annual expected value or seismic risk for a certain year excess probability is estimated for each existing building every year. It is calculated (see FIG. 4B and FIG. 5B). In addition, the earthquake risk assessment after seismic retrofit is performed for each seismic retrofit plan in each existing building. In addition, in the earthquake risk assessment, direct damage due to building damage and indirect damage such as loss of operating income due to facility closure are taken into account as necessary.

  Here, in the relationship between the seismic retrofit cost and the structural seismic index standardized by the repurchasing price, when the seismic retrofit cost increases to some extent, the increase in the structural seismic index tends to reach a peak (see FIG. 10). On the other hand, as for the relationship between the earthquake repair cost standardized by the repurchasing price and the earthquake risk of a certain year, the earthquake risk tends to decrease as the earthquake repair cost increases (see FIG. 11).

In addition, paying attention to the cash flow stream x before and after the seismic retrofit and its change, if the cost expenditure due to the seismic retrofit occurs at t ₀ , the earthquake risk is reduced, and apparently positive flows x ₁ , x ₂ ,..., X _n occurs after time t ₁ (see FIG. 5C). In other words, the rent income and sale price of existing buildings will increase due to the seismic retrofit. Therefore, by calculating the internal rate of return IRR of the cash flow stream x for each earthquake-proof improvement plan, the cost-effectiveness of the earthquake-proof improvement can be compared.

Therefore, in this building evaluation system 1, it is determined whether or not to take into account changes in rent income and sale prices (changes in the return yield R) of existing buildings due to seismic retrofit (ST5). When this is taken into consideration, the increase in rent revenue t _{0 to} t _n-1 and the increase in sales price t _n due to the seismic retrofit are calculated, and the cash flow stream x is corrected as necessary. (ST6) (see FIGS. 8C and 8D). Moreover, the period for obtaining the cash flow stream x is up to the in-service period of each existing building.

  Note that changes in rent income and sales prices due to earthquake-resistant repairs are considered when it is judged that the impact of earthquake-resistant repairs is significant.

  Next, the internal rate of return IRR of the cash flow stream x for each seismic retrofit plan is calculated for each existing building (ST7) (see FIG. 6). At this time, if there are a plurality of seismic retrofit plans for an existing building, the internal rate of return IRR for reducing the earthquake risk is calculated for each seismic retrofit plan (earthquake retrofit investment). In this example, changes in rent income and sale price of existing buildings due to seismic retrofit are not taken into account.

  Next, the internal rate of return IRR of each existing building is compared for each seismic retrofit plan, and the seismic retrofit plan with a higher internal rate of return IRR is selected (ST8) (see FIG. 6). In this embodiment, no. The earthquake-proof repair plan a was selected for the existing building No. 1, The seismic retrofit plan d was selected in the existing building No. 2, and Seismic retrofit plan e is selected in 3 existing buildings.

  Next, the importance factor of the existing building is multiplied by the internal rate of return IRR, and the priority order of the earthquake-proof repair on the existing building is determined based on the calculation result (ST9) (see FIG. 6). . In this embodiment, No. 1 is the highest priority. No. 2 is the seismic retrofit plan d. No. 1 is the earthquake-resistant repair plan a for the existing building, and No. 3 is No. 3. It is seismic retrofit plan e for 3 existing buildings.

[effect]
In this building evaluation system 1, as described above, the earthquake risk of the existing building with respect to the seismic retrofit plan is calculated for each existing building, and the internal rate of return IRR for the seismic retrofit plan is calculated based on this earthquake risk. The And the priority of the earthquake-proof repair concerning an existing building is determined based on this internal rate of return IRR. This has the advantage that the cost effectiveness of seismic retrofitting can be objectively grasped for each existing building.

  In addition, in the conventional building evaluation system, the above-mentioned formula for the present value PV of the regular positive flow c is applied by applying the above-mentioned formula, and the internal profit for the cost of seismic retrofitting (hereinafter referred to as seismic retrofitting cost). There is one that calculates the rate IRR (Nakamura Takaaki et al., “Decision Making for Earthquake-Resistant Investment by Investment Yield”, Journal of Japan Society of Civil Engineers, No. 745 / I-65, pp. 203-207, published in October 2003. reference). In such a conventional building evaluation system, the seismic retrofit cost is assumed to be an increase of the asset value c / R of the existing building as it is.

  However, in the profit return method (direct return method), although the asset value c / R changes due to changes in rent income and sale price, the seismic retrofit cost does not necessarily increase the asset value c / R as it is. In the case of an existing building, the return yield R varies depending on the location, grade, and earthquake resistance (whether the old standard or the current standard) of the existing building. For this reason, in such a conventional building evaluation system, there is a problem that the cost effectiveness of seismic retrofit cannot be objectively grasped when determining the priority of seismic retrofit. In this respect, in this building evaluation system 1, since the priority of earthquake-resistant repairs on existing buildings is determined based on the evaluation of earthquake risk, the cost-effectiveness of earthquake-proof repairs can be objectively grasped There is.

In addition, other conventional building evaluation systems examine the cost effectiveness of multiple seismic retrofitting proposals (Nobuhiro Hiyoshi, “Insurance and Risk Management”, non-life insurance course texts, general research on non-life insurance business) (See 2002 issue). In such a conventional building evaluation system, a reduction amount of the annual expected loss amount (hereinafter referred to as the annual expected loss reduction amount) is calculated by comparing the current state and the annual expected loss amount due to the earthquake after each seismic retrofit. And the amount of earthquake-proof repair costs divided by the depreciation period. Then, the positive / negative of x ₀ / n + c is determined with the initial investment amount x ₀ as the seismic retrofit cost, the depreciation period as n years, and the annual expected loss reduction due to the seismic retrofit as the net income c. If x ₀ / n + c is positive, it is determined that the cost-effective balance is good.

  However, in such a conventional building evaluation system, the cash flow stream x is not discounted by the present value PV. In addition, it does not take into account the timing of earthquake-resistant repairs on existing buildings, and changes in rent income and selling prices due to earthquake-proof repairs. For this reason, in such a conventional building evaluation system, there is a problem that the cost effectiveness of seismic retrofit cannot be objectively grasped when determining the priority of seismic retrofit. In this respect, in this building evaluation system 1, the priority of seismic retrofit is determined taking into account the timing of seismic retrofit and the changes in rent income and selling prices resulting from seismic retrofit, so the cost effectiveness of seismic retrofit is objective. There is an advantage to be grasped automatically.

[Consideration of seismic retrofit timing]
In addition, when the change in the rent income and the sale price due to the seismic retrofit are taken into account, it is preferable to consider the timing of the seismic retrofit as well (see FIGS. 7 and 8). This has the advantage that the cost-effectiveness of seismic retrofitting can be grasped more objectively.

For example, the implementation time of the earthquake-resistant repair is in the case of the t ₂ point in time, rental income and the sale price of existing buildings by seismic renovation to increase from t ₂ point in time. Accordingly, the cash flow stream x is corrected in accordance with the increase in the rental income and the selling price. Then, the internal rate of return IRR is calculated in the same manner as described above for a plurality of seismic retrofit implementation periods (ST7), and the optimal implementation period is selected based on this. In addition, when there are a plurality of seismic retrofit plans for an existing building, these seismic retrofit plans are compared based on the internal rate of return IRR and selected in the same manner as described above (ST8). Then, a numerical value obtained by multiplying the internal rate of return IRR by the importance coefficient is compared, and the priority order of renovation of the existing building is determined (ST9).

  As described above, the building evaluation system and the building evaluation method according to the present invention are useful in that the cost-effectiveness of seismic retrofit can be objectively grasped for each seismic retrofit plan of each existing building.

It is a hardware block diagram which shows the building evaluation system concerning Example 1 of this invention. It is a functional block diagram which shows the building evaluation system concerning Example 1 of this invention. It is a flowchart which shows the building evaluation system concerning Example 1 of this invention. It is explanatory drawing which shows the cash flow stream sequence before and after earthquake-proof repair, and its change. It is explanatory drawing which shows the cash flow stream sequence before and after earthquake-proof repair, and its change. It is a graph which shows the example of calculation of the internal rate of return with respect to each earthquake-proof repair plan. It is explanatory drawing which shows the cash flow stream sequence before and after earthquake-proof repair when the earthquake-proof repair time is considered, and its change. It is explanatory drawing which shows the cash flow stream sequence before and after earthquake-proof repair when the earthquake-proof repair time is considered, and its change. It is explanatory drawing which shows the cash flow stream sequence which arises regularly. It is a graph which shows the relationship between the earthquake-proof repair cost normalized by the re-procurement price, and a structural earthquake-resistance index. It is a graph which shows the relationship between the earthquake-proof repair expense standardized by the replacement price and the earthquake risk of a certain year.

Explanation of symbols

1 Building Evaluation System 2 Controller 21 CPU
22 ROM
23 RAM
24 interface circuit 2a first evaluation unit 2b second evaluation unit 2c third evaluation unit 2d fourth evaluation unit 2e fifth evaluation unit 3 input device 4 output device 5 data file

Claims (4)

In a building evaluation system that evaluates the priority of seismic retrofitting for multiple existing buildings,
Current seismic risk assessment means for obtaining seismic risk for each existing building in time series based on at least the existing building fragility data, active fault data, historical earthquake data and ground data,
Has been set for each of the existing building, on the basis of the relationship between the scaled earthquake-resistant repair costs and Seismic Index of Structure by the replacement cost, the time the earthquake risk of one or more of earthquake-resistant repair plan for each existing buildings Seismic retrofit plan earthquake risk assessment means required for the series,
Based on the seismic risk determined by the earthquake improvement plan earthquake risk evaluation means, a cash flow stream of each seismic retrofit plan corresponding to the time series is obtained, and an internal for each seismic retrofit plan is obtained based on the cash flow stream sequence. Internal rate of return calculation means for calculating the rate of return for each seismic retrofit plan ,
A multiplication value obtained by multiplying the internal rate of return of each seismic retrofit plan by the importance coefficient indicating the importance between the existing buildings is obtained for each seismic retrofit plan, and for each existing building based on the multiplication value. A priority determination output means for selecting an optimal earthquake-proof improvement plan, and determining and outputting the priority of the earthquake-proof improvement for each existing building based on the multiplication value of the selected optimal earthquake-proof improvement plan;
Building evaluation system comprising the. The said internal rate of return calculation means calculates | requires the said internal rate of return by calculating | requiring the said cash flow stream including the change of the rent income and sale price of the existing building by earthquake-proof repair , The said internal rate of return is calculated. Building evaluation system. 3. The building evaluation system according to claim 2, wherein the internal rate of return calculation means calculates the internal rate of return by arranging an earthquake-proof repair execution time at an arbitrary time on the cash flow stream. . In the building evaluation method that evaluates the priority of earthquake-resistant repairs on multiple existing buildings,
Based on at least the existing building fragility data, active fault data, historical earthquake data, and ground data stored in the storage means, the current earthquake risk assessment means Current seismic risk assessment steps to obtain seismic risk in time series,
Based on the relationship between the seismic retrofit cost and the structural seismic index, which are set in the storage means for each existing building and standardized by the replacement price, the seismic retrofit plan earthquake risk evaluation means A seismic retrofit plan earthquake risk step for determining the seismic risk of one or more seismic retrofit plans for the time series according to the time series;
An internal rate of return calculation means obtains a cash flow stream of each earthquake-resistant repair plan corresponding to the time series based on the earthquake risk obtained by the earthquake repair plan earthquake risk evaluation step, and based on the cash flow stream sequence An internal rate of return calculation step for calculating an internal rate of return for each seismic retrofit plan for each seismic retrofit plan,
The priority determining means obtains a multiplication value obtained by multiplying the internal rate of return of each seismic retrofit plan by an importance coefficient indicating the importance between the existing buildings for each seismic retrofit plan, and based on the multiplied value A priority determination output step of selecting an optimum seismic retrofit plan for each existing building and determining and outputting a priority of the seismic retrofit for each existing building based on the multiplication value of the selected optimal seismic retrofit plan When,
The building evaluation method characterized by including.

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