WO2024111094A1

WO2024111094A1 - Determination method, determination device, and program

Info

Publication number: WO2024111094A1
Application number: PCT/JP2022/043404
Authority: WO
Inventors: 陽祐竹内; みずき田端; 良牧野; 潤一郎玉松
Original assignee: 日本電信電話株式会社
Priority date: 2022-11-24
Filing date: 2022-11-24
Publication date: 2024-05-30

Abstract

A determination method according to the present disclosure is executed by a determination device (1) that determines the necessity of repair of a reinforced concrete structure (2), which comprises reinforcing bars (21) and concrete (22) covering the reinforcing bars (21), and which defines an interior space (IS). The determination method includes: a stress degree calculation step for calculating a deterioration stress strain relationship indicating a correspondence relationship between stress degree and strain of a deteriorated reinforced concrete structure (2-B), using a deterioration model representing a deteriorated reinforced concrete structure, which is a reinforced concrete structure from which a concrete cover on the interior space (IS) side has peeled off; and a determination step for determining whether or not repair of the reinforced concrete structure is necessary, on the basis of the deterioration stress strain relationship and an assumed stress level (fw) that is expected to occur in the environment where the reinforced concrete structure (2) is installed.

Description

Determination method, determination device, and program

This disclosure relates to a determination method, a determination device, and a program.

　Traditionally, manholes made of reinforced concrete (RC) have been known to deteriorate. Causes of manhole deterioration include external forces, Alkali Silica Reaction (ASR) (see Non-Patent Document 1), poor concrete quality or poor construction, or concrete spalling and cracking due to corrosion of rebar caused by carbonation or salt damage.

Such deterioration of manholes is generally confirmed by visual inspection for cracks, spalling of concrete, exposed reinforcement, etc. It is also known that deterioration of manholes can be monitored by methods such as using strain gauges (see Non-Patent Document 2), using optical fiber sensors (see Non-Patent Document 3), and electrochemical detection of rebar corrosion (see Non-Patent Document 4).

The standards and timing for repairing concrete structures such as manholes are determined by the manager of the concrete structure, who repairs the concrete to prevent the progression of corrosion of the reinforcing bars contained in the concrete structure. For example, it is known that surface coating, cathodic protection, etc. are performed to repair concrete structures depending on the cause of deterioration, the state of deterioration, etc. (see Non-Patent Document 5).

Furthermore, since the location, size, and type (cracks, concrete spalling, exposed rebar, etc.) of deterioration differs for each concrete structure, it is also known to conduct structural analysis individually (see Non-Patent Document 6).

However, reinforced concrete structures such as manholes are designed based on a safety factor, assuming that they will deteriorate, so that they will be maintained even if they deteriorate to a certain extent. For this reason, even if cracks or spalling occur in the concrete due to external forces, ASR, or poor quality or poor construction of the concrete, prompt repair may not be necessary if the remaining strength is sufficient when considering a predetermined safety factor. In contrast, if repairs are made without a strength assessment through structural analysis every time cracks or spalling in the concrete are confirmed using the above-mentioned technology, it is difficult to reduce the management costs for maintaining the safety of reinforced concrete structures. Furthermore, if cracks or spalling are confirmed and structural analysis is conducted, it is difficult to appropriately assess the deterioration of the current reinforced concrete structure if the design drawings used when the reinforced concrete structure was constructed are used.

Also, as mentioned above, using technology that determines whether or not a structure needs repairs individually makes it difficult to comprehensively determine whether or not a structure needs repairs in various states. This results in a high processing load, making it difficult to efficiently determine whether or not a structure needs repairs.

The purpose of this disclosure, made in consideration of these circumstances, is to provide a determination method, determination device, and program that can efficiently determine whether or not repairs are required in reinforced concrete structures while reducing the management costs required to maintain the safety of the reinforced concrete structures.

In order to solve the above problems, the determination method disclosed herein is a determination method executed by a determination device that determines whether or not a reinforced concrete structure that includes reinforcing bars and concrete covering the reinforcing bars and defines an internal space needs to be repaired, and includes a stress calculation step of calculating a deterioration stress-strain relationship that indicates the correspondence between stress and strain of the deteriorated reinforced concrete structure using a deterioration model that represents the deteriorated reinforced concrete structure, which is the reinforced concrete structure in which the concrete covering has peeled off on a predetermined surface on the internal space side, and a determination step of determining whether or not the reinforced concrete structure needs to be repaired based on the deterioration stress-strain relationship and an assumed stress that is assumed to occur in the environment in which the reinforced concrete structure is installed.

In order to solve the above problems, the determination device according to the present disclosure is a determination device that determines whether or not a reinforced concrete structure that includes reinforcing bars and concrete covering the reinforcing bars and defines an internal space needs to be repaired, and includes a stress calculation unit that calculates a deterioration stress-strain relationship that indicates the correspondence between stress and strain of the deteriorated reinforced concrete structure using a deterioration model that represents the deteriorated reinforced concrete structure, which is the reinforced concrete structure in which the concrete cover has peeled off on a specified surface on the internal space side, and a determination unit that determines whether or not the reinforced concrete structure needs to be repaired based on the deterioration stress-strain relationship and an assumed stress that is assumed to occur in the environment in which the reinforced concrete structure is installed.

In addition, to solve the above problem, the program disclosed herein causes a computer to execute the degradation determination method described above.

The assessment method, assessment device, and program disclosed herein can efficiently determine whether or not repairs are required in reinforced concrete structures, while reducing management costs for maintaining the safety of the reinforced concrete structures.

FIG. 1 is a perspective view illustrating an example of a determination device according to a first embodiment of the present disclosure. 2 is a schematic diagram showing an example of a reinforced concrete structure for which the judgment device shown in FIG. 1 judges whether or not repair is required. FIG. FIG. 2B is a cross-sectional view of the reinforced concrete structure shown in FIG. 2A. FIG. 2C is a partially enlarged view of the reinforced concrete structure shown in FIG. 2B. FIG. 1 is a diagram showing an example of a healthy but deteriorated reinforced concrete structure. FIG. 1 is a diagram showing an example of a deteriorated reinforced concrete structure. FIG. 2 is a diagram showing stress-strain curves of a healthy and deteriorated reinforced concrete structure and a deteriorated reinforced concrete structure. 4 is a flowchart showing an example of an operation executed by the determination device shown in FIG. 1 . FIG. 11 is a schematic diagram illustrating an example of a determination device according to a second embodiment of the present disclosure. 7 is a flowchart showing an example of an operation executed by the determination device shown in FIG. 6 . FIG. 2 is a diagram illustrating an example of a hardware configuration of the determination device illustrated in FIG. 1 .

First Embodiment
<Configuration of Determination Device>
A determination device 1 according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an example of the determination device 1 according to the first embodiment.

The judgment device 1 judges whether or not repair is required for a reinforced concrete structure 2 that includes reinforcing bars 2a and concrete 2b that covers the reinforcing bars 2a and defines an internal space IS, as shown in Figures 2A and 2B.

In this example, the reinforced concrete structure 2 defines an internal space IS by an upper surface member 21, a side surface member 22, and a lower surface member 23. As an example, the upper surface member 21 is an upper floor slab, the side surface member 22 is a side wall, and the lower surface member 23 is a lower floor slab. Furthermore, a hole HL is defined in the upper surface member 21 for people to enter and exit the internal space IS. Furthermore, the upper surface member 21, the side surface member 22, and the lower surface member 23 are each composed of reinforcing bars 2a and concrete 2b covering the reinforcing bars 2a (in FIG. 2B, the reinforcing bars 2a are shown in the upper surface member 21). Furthermore, as shown in FIG. 2C, cracks 2c and peeling 2d of the concrete 2b may occur in the reinforced concrete structure 2, and the peeling 2d may become large and lead to exposed reinforcing bars 2e. In this example, the reinforced concrete structure 2 is a rectangular parallelepiped, but this is not limited to this.

There are multiple standards for reinforced concrete structures 2, and the sizes of the reinforced concrete structures 2 for each standard are different. In addition, reinforced concrete structures 2 for some standards are similar in shape to each other. For example, in an example where the reinforced concrete structure 2 is a manhole, a straight-line type No. 1 (S-1) manhole of one standard and a straight-line type No. 2 (S-2) manhole of another standard are similar in shape to each other.

As shown in FIG. 1, the judgment device 1 includes an input unit 11, a stress level calculation unit 12, a judgment unit 13, and an output unit 14. The input unit 11 is configured with an input interface. The input interface may be a communication interface. For example, standards such as Ethernet (registered trademark), FDDI (Fiber Distributed Data Interface), and Wi-Fi (registered trademark) may be used for the communication interface. The stress level calculation unit 12 and the judgment unit 13 are configured with a controller. The controller may be configured with dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array), may be configured with a processor, or may be configured to include both. The output unit 14 is configured with an output interface. The output interface may be a communication interface.

The input unit 11 accepts input of rust information relating to rust or rust traces on the reinforced concrete structure 2. The rust information may be information indicating whether or not there is rust or rust traces on the reinforced concrete structure 2. For example, the rust information may be information based on the results of observation by an inspector, stored in an inspection device including a database, and input from the inspection device to the input unit 11. The rust information may also be image information indicating an image of the reinforced concrete structure 2 captured by an imaging device such as a camera, and input from the imaging device to the input unit 11.

The stress calculation unit 12 uses a deterioration model representing a deteriorated reinforced concrete structure 2-B (see Figure 3B), which is a reinforced concrete structure 2 in which the concrete cover has peeled off on a specified surface on the internal space IS side, to calculate a deterioration stress-strain relationship that shows the correspondence between stress and strain in the deteriorated reinforced concrete structure 2-B. In the deteriorated reinforced concrete structure 2-B, the concrete cover has peeled off over the entire surface of the specified surface on the internal space IS side. In the example shown in Figure 3B, the specified surface is the surface of the upper surface member 21.

The deterioration model is a model (see FIG. 3B) that represents a deteriorated reinforced concrete structure 2-B in which the concrete covering on a specified surface on the internal space IS side of one surface member (e.g., upper surface member 21) has been peeled off from a healthy reinforced concrete structure 2-A, which is a reinforced concrete structure 2 in which no deterioration has occurred, as shown in FIG. 3A. The deterioration model can be a solid model.

Here, the stress calculation unit 12 will be described in detail. As shown in FIG. 1, the stress calculation unit 12 has a cover element number setting unit 121, a finite element model construction unit 122, a finite element analysis unit 123, and a calculation unit 124.

The cover element number setting unit 121 sets the size and number of meshes for constructing a deterioration model by the finite element method. Specifically, as shown in FIG. 3B, the cover element number setting unit 121 sets the size and number of meshes that can be set by the finite element method so that the concrete cover on a specified surface on the internal space IS side of the reinforced concrete structure 2 is peeled off and the length of peeled concrete 2b is maximized within the range where the reinforcing bar 2a is not exposed. For example, the cover element number setting unit 121 sets the size and number of meshes so that the length Ly (see FIG. 2C) of peeled concrete 2b in the normal direction of the surface of the upper surface member 21 is shorter than the length d (see FIG. 2C) from the surface of the upper surface member 21 on the internal space IS side to the reinforcing bar 2a, and is the maximum value that can be set by the finite element method.

The finite element model construction unit 122 can construct a deterioration model by the finite element method using the size and number of meshes determined by the cover element number setting unit 121. Because the cover element number setting unit 121 sets the size and number of meshes as described above, the finite element model construction unit 122 can construct a deterioration model representing a deteriorated reinforced concrete structure 2-B in which the concrete cover on a specified surface on the internal space IS side of the reinforced concrete structure 2-B has been peeled off and the length of peeled concrete 2b is the longest within the range where the reinforcing bars 2a are not exposed. This allows the finite element model construction unit 122 to construct a deterioration model that comprehensively represents the reinforced concrete structure 2 in various states of deterioration, large and small, in the early stages of the deterioration process caused by corrosion, external forces, etc.

The finite element model construction unit 122 may also construct a sound model representing the sound reinforced concrete structure 2-A using the finite element method.

The finite element analysis unit 123 uses the deterioration model to calculate a deterioration stress-strain relationship that indicates the corresponding relationship between stress and strain in the deteriorated reinforced concrete structure 2-B. The finite element analysis unit 123 may also use the sound model to calculate a healthy stress-strain relationship that indicates the corresponding relationship between stress and strain in the healthy reinforced concrete structure 2-A.

The deteriorated stress-strain relationship and the healthy stress-strain relationship may each be represented by a stress-strain curve as shown in Fig. 4. Fig. 4 shows a design value _XA of the stress intensity of the healthy reinforced concrete structure 2-A and a design value _XB of the stress intensity of the deteriorated reinforced concrete structure 2-B. The design value of the stress intensity is the maximum value of the stress in a range in which the stress and the strain have an approximately linear relationship. "Approximately linear" means that the rate of change of the stress with respect to the strain (the slope of the curve shown in Fig. 4) is approximately constant (the rate of change is equal to or less than a threshold value).

The calculation unit 124 calculates the allowable stress f Bα of the deteriorated reinforced concrete structure 2-B based on the design value X _B of the stress of the deteriorated reinforced concrete structure 2-B indicated by the deterioration stress-strain relationship and the safety factor _α . The safety factor α is a ratio of the allowable stress to the fracture stress of the material used in the reinforced concrete structure 2, and is a value greater than 1 that is determined when the reinforced concrete structure 2 is designed. Specifically, the calculation unit 124 calculates the value obtained by dividing the design value X _B of the stress by the safety factor α as the allowable stress f _Bα . FIG. 4 shows, as examples, the allowable stress f _B2 when the safety factor α is 2 and the allowable stress f _B3 when the safety factor α is 3.

The calculation unit 124 may also calculate the allowable stress fAα of the healthy reinforced concrete structure 2-A represented by the healthy model based on the design value _XA of the stress of the healthy reinforced concrete structure 2-A and the safety factor α, which are shown by the healthy stress-strain relationship. Specifically, the calculation unit 124 may calculate the value obtained by dividing the design value _XA of the stress by the safety factor α as the allowable stress _fAα . In Fig. 4, as examples, the allowable stress _fA2 when the safety factor α is 2 and the allowable stress _fA3 when the safety factor α _is 3 are shown.

The judgment unit 13 may judge whether or not repair of the reinforced concrete structure 2 is necessary based on the rust information. If there is rust or traces of rust on the reinforced concrete structure 2, it is expected that the reinforcing bars 2a are exposed and therefore deterioration is progressing. On the other hand, if there is no rust or traces of rust on the reinforced concrete structure 2, it is expected that the reinforcing bars 2a are not exposed to the atmosphere and therefore deterioration may not be progressing.

Therefore, the determination unit 13 may determine whether or not there is rust or rust traces in the reinforced concrete structure. If it is determined that there is rust or rust traces in the reinforced concrete structure, the determination unit 13 may determine that repair of the reinforced concrete structure 2 is necessary. If it is determined that there is no rust or rust traces in the reinforced concrete structure 2, the determination unit 13 may determine whether or not repair of the reinforced concrete structure 2 is necessary based on the deterioration stress-strain relationship and the assumed stress intensity _fw , as will be described in detail below.

The judgment unit 13 judges whether or not repair of the reinforced concrete structure 2 is necessary based on the deterioration stress-strain relationship and the assumed stress intensity _{fw that} is assumed to occur in the environment in which the reinforced concrete structure 2 is installed.

Specifically, the judgment unit 13 judges whether or not the allowable stress fBα obtained by dividing the design value _XB of the stress of the deteriorated reinforced concrete structure 2-B, which is indicated by the deterioration stress-strain relationship, by the safety factor α of the reinforced concrete structure, is equal to or _greater than the assumed stress _fw that is assumed to occur in the environment in which the reinforced concrete structure 2 is installed. If the judgment unit 13 judges that the allowable stress _fBα is equal to or greater than the assumed stress _fw , it judges that repair of the reinforced concrete structure 2 is not necessary. Furthermore, if the judgment unit 13 judges that the allowable stress _fBα is less than the assumed stress _fw , it judges that repair of the reinforced concrete structure 2 is necessary.

As described above, in a configuration in which the rust information is image information showing an image of the reinforced concrete structure 2, the judgment unit 13 judges whether or not there is rust or rust traces in the reinforced concrete structure 2 based on the image information. Specifically, the judgment unit 13 uses any image processing to judge that there is rust or rust traces in the reinforced concrete structure 2 when an image of rust or rust traces is detected in the image of the reinforced concrete structure 2. Furthermore, the judgment unit 13 uses the image processing to judge that there is no rust or rust traces in the reinforced concrete structure 2 when an image of rust or rust traces is not detected in the image of the reinforced concrete structure 2.

The output unit 14 outputs the judgment result judged by the judgment unit 13. For example, the output unit 14 may display the judgment result on a display device configured as an integral part of or separate from the judgment device 1. The output unit 14 may also output the judgment result to another device via a communication network, or may output the judgment result by any method such as voice.

<Operation of Determination Device>
Here, the operation of the determination device 1 according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the operation of the determination device 1 according to the first embodiment. The operation of the determination device 1 described with reference to Fig. 5 corresponds to an example of a determination method executed by the determination device 1 according to the first embodiment.

In step S11, the input unit 11 accepts input of rust information relating to rust or rust traces on the reinforced concrete structure 2 (input step).

In step S12, the judgment unit 13 judges whether or not there is rust or traces of rust on the reinforced concrete structure 2 based on the rust information (judgment step).

If it is determined in step S12 that there is rust or traces of rust on the reinforced concrete structure 2, then in step 16 the determination unit 13 determines that repair of the reinforced concrete structure 2 is necessary (determination step).

If it is determined in step 12 that there is no rust or traces of rust in the reinforced concrete structure 2, in step S13, the stress calculation unit 12 calculates the deterioration stress-strain relationship (stress calculation step), and in steps S14 to S16, the judgment unit 13 judges whether or not repair of the reinforced concrete structure 2 is necessary based on the deterioration stress-strain relationship and the assumed stress _fw (judgment step).

Specifically, in step S13, the stress calculation unit 12 uses a deterioration model representing a deteriorated reinforced concrete structure 2-B, which is a reinforced concrete structure 2 in which the concrete cover has peeled off on a specified surface on the internal space IS side, to calculate a deterioration stress-strain relationship that indicates the correspondence between stress and strain of the deteriorated reinforced concrete structure 2-B (stress calculation step). At this time, the stress calculation unit 12 determines the size and number of meshes for constructing the deterioration model using the finite element method, and can construct the deterioration model using the finite element method using the size and number of meshes.

In step S14, the judgment unit 13 judges whether the allowable stress fBα obtained by dividing the design value _XB of the stress of the deteriorated reinforced concrete structure 2-B shown in the deterioration stress-strain relationship by the safety factor α of the reinforced concrete structure ₂ is equal to or greater than the assumed stress _fW (judgment step).

If it is determined in step S14 that the allowable stress f _Bα is equal to or greater than the assumed stress f _w , then in step S15, the determination unit 13 determines that repair of the reinforced concrete structure 2 is not necessary (determination step).

If it is determined in step S14 that the allowable stress f _Bα is less than the assumed stress f _w , then in step S16, the determination unit 13 determines that repair of the reinforced concrete structure 2 is necessary (determination step).

In step S17, the output unit 14 outputs the determination result (output step).

As described above, the determination method according to the first embodiment is a determination method executed by a determination device 1 that determines whether or not the reinforced concrete structure 2 that includes the reinforcing bar 2a and the concrete 2b covering the reinforcing bar 2a and defines an internal space IS needs to be repaired. The determination method according to the first embodiment includes a stress calculation step of calculating a deterioration stress-strain relationship that indicates a correspondence relationship between the stress and strain of the deteriorated reinforced concrete structure 2-B using a deterioration model that represents a deteriorated reinforced concrete structure 2-B that is a reinforced concrete structure 2 in which the concrete covering on a predetermined surface on the internal space IS side has peeled off, and a determination step of determining whether or not the reinforced concrete structure 2 needs to be repaired based on the deterioration stress-strain relationship and an assumed stress f _w that is assumed to occur in the environment in which the reinforced concrete structure 2 is installed.

This makes it possible to appropriately determine whether or not repairs are necessary for the reinforced concrete structure 2. Therefore, for example, even if cracks or the like are confirmed by visual inspection, repairs to the reinforced concrete structure 2 that has the necessary strength for maintenance can be postponed. This makes it possible to reduce the management costs for maintaining the safety of the reinforced concrete structure.

Furthermore, if structural analysis were performed using a model that reflected the actual deterioration state of the reinforced concrete structure 2, the processing load would be large, making it difficult to make an efficient judgment. In contrast, in the judgment method according to the first embodiment, the deterioration model can comprehensively represent reinforced concrete structures in various deterioration states, to a large or small extent, making it possible to efficiently judge whether or not repairs are required for the reinforced concrete structure.

The determination method according to the first embodiment further includes an input step of receiving input of rust information related to rust or rust traces in the reinforced concrete structure 2. The determination step includes a step of determining whether or not the reinforced concrete structure 2 has rust or rust traces based on the rust information, determining that the reinforced concrete structure 2 needs repair when it is determined that the reinforced concrete structure 2 has rust or rust traces, and determining whether or not the reinforced concrete structure 2 needs repair based on the deterioration stress-strain relationship and the assumed stress f _w when it is determined that the reinforced concrete structure 2 does not have rust or rust traces. In this way, according to the determination method according to the first embodiment, it is possible to immediately repair the reinforced concrete structure 2 determined to have rust or rust traces without making a determination using the stress-strain relationship, and it is possible to reduce the processing load because a determination is made using the stress-strain relationship for the reinforced concrete structure 2 determined to have no rust or rust traces.

<<Second embodiment>>
<Configuration of Determination Device>
A determination device 1-1 according to the second embodiment will be described with reference to Fig. 6. Fig. 6 is a schematic diagram showing an example of the determination device 1-1 according to the present embodiment. In the second embodiment, the same reference numerals are used for the same functional units as those in the first embodiment, and the description thereof will be omitted.

The judgment device 1-1 includes an input unit 11, a stress level calculation unit 12-1, a judgment unit 13-1, and an output unit 14. The stress level calculation unit 12-1 and the judgment unit 13-1 are configured by a controller.

The stress calculation unit 12-1 has a cover element number setting unit 121, a finite element model construction unit 122, a finite element analysis unit 123-1, a calculation unit 124-1, and a deterioration ratio calculation unit 125.

The finite element analysis unit 123-1 calculates a deterioration stress-strain relationship that indicates the correspondence between stress and strain of the deteriorated reinforced concrete structure 2-B of the first standard, using a deterioration model that represents the deteriorated reinforced concrete structure 2-B of the first standard, which is a reinforced concrete structure 2 of the first standard in which the concrete cover on a specified surface on the internal space IS side has peeled off. This process corresponds to the process in which the finite element analysis unit 123-1 in the first embodiment described above calculates the deterioration stress-strain relationship. In other words, the deteriorated reinforced concrete structure in the first embodiment is a deteriorated reinforced concrete structure of the first standard in the second embodiment.

Furthermore, the finite element analysis unit 123-1 calculates a first healthy stress-strain relationship that shows the correspondence between stress and strain of the healthy reinforced concrete structure 2-A of the first standard, which is a reinforced concrete structure 2 of the first standard that has not deteriorated, using a healthy model that represents the healthy reinforced concrete structure 2-A of the first standard.

The deterioration ratio calculation unit 125 calculates the deterioration ratio β. The deterioration ratio β is the ratio of the design value _XB of the stress intensity of the deteriorated reinforced concrete structure 2-B of the first standard, which is indicated by the deteriorated stress-strain relationship, to the design value _XA of the stress intensity of the healthy reinforced concrete structure 2-A of the first standard, which is indicated by the first healthy stress-strain relationship.

Furthermore, the finite element analysis unit 123-1 calculates a second healthy stress-strain relationship that shows the correspondence between stress and strain of a healthy reinforced concrete structure 2-A of the second standard, using a healthy model that represents a healthy reinforced concrete structure 2-A of the second standard, which is similar in shape but different in size from the first standard.

Furthermore, the calculation unit 124-1 calculates a value obtained by multiplying the allowable stress _fA'α of the healthy reinforced concrete structure 2-A of the second standard based on the second healthy stress-strain relationship by the deterioration ratio β as the allowable stress _fB'α of the deteriorated reinforced concrete structure 2-B of the second standard. Here, the calculation unit 124-1 can calculate a value obtained by dividing the design value _XA' of the stress of the reinforced concrete structure of the second standard shown in the second healthy stress-strain relationship by the safety factor α of the reinforced concrete structure 2 as the allowable stress _fA'α .

The judgment unit 13-1 judges whether or not repair of the reinforced concrete structure 2 of the second standard is necessary, similarly to the first embodiment, based on whether the allowable stress f _B'α of the deteriorated reinforced concrete structure 2-B of the second standard is equal to or greater than the assumed stress f _w' .

Specifically, the judgment unit 13-1 judges whether the allowable stress f _B'α of the deteriorated reinforced concrete structure 2-B of the second standard is equal to or greater than the assumed stress f _w' assumed to occur in the environment in which the reinforced concrete structure 2 of the second standard is installed. If the judgment unit 13-1 judges that the allowable stress f _B'α is equal to or greater than the assumed stress f _w' , it judges that the reinforced concrete structure 2 of the second standard does not need to be repaired. If the judgment unit 13-1 judges that the allowable stress f _B'α is less than the assumed stress f _w' , it judges that the reinforced concrete structure 2 of the second standard needs to be repaired.

Furthermore, the stress calculation unit 12-1 can similarly calculate the allowable stress of a deteriorated reinforced concrete structure 2-B of a kth standard (k is an integer equal to or greater than 3) that is similar in shape to the first and second standards but different in size based on the deterioration ratio β. In this case, the judgment unit 13-1 can similarly judge whether or not repairs are necessary for the reinforced concrete structure 2 of the kth standard.

In general, due to the size effect, the larger the reinforced concrete structure 2, the more likely it is to be destroyed at a strength lower than the expected strength. For this reason, it is preferable that the representative model, which is a deterioration model representing the deteriorated reinforced concrete structure 2-B of the first standard, is a model representing the deteriorated reinforced concrete structure 2-B of the standard having the largest size. In such a configuration, the deterioration stress-strain relationship of the reinforced concrete structure 2 of a standard having a size smaller than the reinforced concrete structure 2 represented by the representative model is calculated using the deterioration ratio β, as described above. In this way, by using the largest-sized structure, which is likely to have low strength, as the representative model, a safe evaluation (an evaluation that is less likely to result in a dangerous state) of the concrete structure 2 represented by each model is possible.

<Operation of Determination Device>
Here, the operation of the determination device 1-1 according to the second embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of the operation of the determination device 1-1 according to the second embodiment. The operation of the determination device 1-1 described with reference to Fig. 7 corresponds to an example of a determination method of the determination device 1-1 according to the second embodiment for determining whether or not repair is required for a reinforced concrete structure 2 that includes reinforcing bars 2a and concrete 2b covering the reinforcing bars 2a and defines an internal space IS.

The operation of the judgment device 1-1 to make a judgment on a reinforced concrete structure 2 of the first standard is similar to the operation of the judgment device 1 of the first embodiment described with reference to FIG. 5. The following describes the operation of the judgment device 1-1 to make a judgment on a reinforced concrete structure 2 of the second standard.

In step S21, the stress calculation unit 12-1 calculates a first healthy stress-strain relationship that indicates the correspondence between stress and strain of the healthy reinforced concrete structure 2-A of the first standard, using a healthy model that represents the healthy reinforced concrete structure 2-A, which is a reinforced concrete structure of the first standard in which no deterioration has occurred. This operation corresponds to the operation of step S13 in the first embodiment described above. Therefore, after the operation of the first embodiment has been executed, the operation of step S21 does not need to be executed.

In step S22, the stress calculation unit 12-1 uses a healthy model representing a healthy reinforced concrete structure 2-A, which is a reinforced concrete structure of the first standard and in which no deterioration has occurred, to calculate a first healthy stress-strain relationship that shows the correspondence between stress and strain of the healthy reinforced concrete structure 2-A of the first standard (stress calculation step).

In step S23, the deterioration ratio calculation unit 125 calculates a deterioration ratio β, which is the ratio of the design value _XB of the stress intensity of the deteriorated reinforced concrete structure 2-B of the first standard, which is indicated by the deteriorated stress-strain relationship, to the design value _XA of the stress intensity of the healthy reinforced concrete structure 2-A of the first standard, which is indicated by the first healthy stress-strain relationship (deterioration ratio calculation step).

In step 24, the input unit 11 accepts input of rust information relating to rust or rust traces on the second standard reinforced concrete structure 2 (input step).

In step S25, the judgment unit 13-1 judges whether or not there is rust or traces of rust in the reinforced concrete structure of the second standard based on the rust information (judgment step).

If it is determined in step S25 that the reinforced concrete structure of the second standard has rust or traces of rust, in step 31, the determination unit 13-1 determines that the reinforced concrete structure 2 of the second standard needs repair (determination step).

If it is determined in step 25 that there is no rust or traces of rust in the second standard reinforced concrete structure, in step S26, the stress calculation unit 12-1 calculates the deterioration stress-strain relationship (stress calculation step), and in steps S27 to S31, the judgment unit 13-1 judges whether or not repair of the second standard reinforced concrete structure 2 is necessary based on the deterioration stress-strain relationship and the assumed stress _fw (judgment step).

Specifically, in step S26, the stress calculation unit 12-1 uses a healthy model representing a healthy reinforced concrete structure 2-A of a second standard that is similar in shape but different in size from the first standard to calculate a second healthy stress-strain relationship that shows the correspondence between stress and strain of the healthy reinforced concrete structure 2-A of the second standard (stress calculation step).

Then, the stress calculation unit 12-1 calculates the allowable stress f _A'α of the healthy reinforced concrete structure 2-A of the second standard, based on the healthy stress-strain relationship of the second standard, multiplied by the deterioration ratio β, as the allowable stress f _B'α of the deteriorated reinforced concrete structure 2-B of the second standard (stress calculation step).

Specifically, in step S27, the stress calculation unit 12-1 calculates the allowable stress _fA'α by dividing the design stress value XA _' by the safety factor α (stress calculation step).

In step S28, the stress calculation unit 12-1 calculates the allowable stress f _A'α multiplied by the deterioration ratio β as the allowable stress f _B'α of the deteriorated reinforced concrete structure 2-B of the second standard (stress calculation step).

In step S29, the judgment unit 13-1 judges whether the allowable stress f _B'α of the deteriorated reinforced concrete structure 2-B of the second standard is equal to or greater than the assumed stress f _w' assumed to occur in the environment in which the reinforced concrete structure 2 of the second standard is installed (judgment step).

If it is determined in step S29 that the allowable stress f _B'α is equal to or greater than the assumed stress f _w' , then in step S30, the judgment unit 13-1 judges that repair of the reinforced concrete structure 2 according to the second standard is not necessary (judgment step).

If it is determined in step S29 that the allowable stress f _B'α is less than the assumed stress f _w' , then in step S31, the judgment unit 13-1 judges that repair of the reinforced concrete structure according to the second standard is necessary (judgment step).

In step S32, the output unit 14 outputs the determination result (output step).

In the above-mentioned operation, the judgment device 1-1 may use the deterioration ratio β calculated in step S23 to further repeatedly execute the processes from step S24 onwards to judge whether or not repair is necessary for the deteriorated reinforced concrete structure 2-B of the kth standard (k is an integer equal to or greater than 3). In this case, the judgment device 1-1 does not need to repeatedly execute the processes from step S21 to step S23 described above.

As described above, the judgment method according to the second embodiment further includes a deterioration ratio calculation step. The stress calculation step includes a step of calculating a first healthy stress-strain relationship showing a correspondence relationship between stress and strain of the healthy reinforced concrete structure 2-A of the first standard, using a healthy model representing the healthy reinforced concrete structure 2-A, which is the reinforced concrete structure 2 of the first standard in which deterioration has not occurred. The deterioration ratio calculation step also includes a step of calculating a deterioration ratio β, which is a ratio of a design value _XB of stress of the deteriorated reinforced concrete structure 2-B of the first standard, which is shown by the deteriorated stress-strain relationship, to a design value _XA of stress of the healthy reinforced concrete structure 2-A of the first standard, which is shown by the first healthy stress-strain relationship. The stress calculation step includes a step of calculating a second healthy stress-strain relationship using a healthy model representing a healthy reinforced concrete structure 2-A of a second standard similar in shape to but different in size from the first standard, and calculating a value obtained by multiplying the allowable stress f _A'α of the healthy reinforced concrete structure 2-A of the second standard based on the healthy stress-strain relationship of the second standard by the deterioration ratio β as the allowable stress f _B'α of the deteriorated reinforced concrete structure 2-B of the second standard. The determination step includes a step of determining whether or not the allowable stress f _B'α of the deteriorated reinforced concrete structure 2-B of the second standard is equal to or greater than the assumed stress f _W assumed to occur in the environment in which the reinforced concrete structure of the second standard is installed. As a result, the judgment device 1-1 can easily calculate the allowable stress level f _B'α of the deteriorated reinforced concrete structure 2-B of the second standard compared to the case where the allowable stress level f _B'α is calculated by performing structural analysis using a deterioration model, thereby reducing the processing load of the judgment device 1-1.

<Program>
The above-mentioned determination device 1 and determination device 1-1 can each be realized by a computer 301. In addition, a program for causing the computer 301 to function as the above-mentioned determination device 1 or determination device 1-1 may be provided. In addition, the program may be stored in a storage medium or provided through a network. FIG. 8 is a block diagram showing a schematic configuration of a computer 301 functioning as the determination device 1. The schematic configuration of a computer functioning as the determination device 1-1 is similar. Here, the computer 301 may be a general-purpose computer, a dedicated computer, a workstation, a PC (Personal Computer), an electronic notepad, or the like. The program instructions may be program code, code segments, or the like for performing necessary tasks.

As shown in FIG. 8, computer 301 includes processor 310, ROM (Read Only Memory) 320, RAM (Random Access Memory) 330, storage 340, input section 350, output section 360, and communication interface (I/F) 370. Each component is connected to each other via bus 380 so as to be able to communicate with each other. Processor 310 is specifically a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), SoC (System on a Chip), etc., and may be composed of multiple processors of the same or different types.

Processor 310 controls each component and executes various types of arithmetic processing. That is, processor 310 reads a program from ROM 320 or storage 340, and executes the program using RAM 330 as a working area. Processor 310 controls each component and executes various types of arithmetic processing according to the program stored in ROM 320 or storage 340. In the above-described embodiment, the program related to the present disclosure is stored in ROM 320 or storage 340.

The program may be stored in a storage medium that is readable by computer 301. By using such a storage medium, it is possible to install the program in computer 301. Here, the storage medium on which the program is stored may be a non-transitory storage medium. The non-transitory storage medium is not particularly limited, and may be, for example, a CD-ROM, a DVD-ROM, or a USB (Universal Serial Bus) memory. In addition, the program may be in a form that is downloaded from an external device via a network.

ROM 320 stores various programs and data. RAM 330 temporarily stores programs or data as a working area. Storage 340 is composed of a HDD (Hard Disk Drive) or SSD (Solid State Drive), and stores various programs and data including the operating system.

The input unit 350 is an interface for accepting input of information, and the output unit 360 is an interface for outputting information.

The communication interface 370 is an interface for communicating with external devices.

The following supplementary notes are further disclosed regarding the above embodiment.
[Additional Note 1]
A method for determining whether or not a reinforced concrete structure that includes a reinforcing bar and concrete covering the reinforcing bar and defines an internal space is required, the method being performed by a determination device, comprising:
a stress calculation step of calculating a deterioration stress-strain relationship showing a correspondence relationship between stress and strain of the deteriorated reinforced concrete structure using a deterioration model representing the deteriorated reinforced concrete structure, which is the reinforced concrete structure in which the concrete covering on a predetermined surface on the internal space side has peeled off;
a determination step of determining whether or not the reinforced concrete structure needs repair based on the deterioration stress-strain relationship and an assumed stress intensity assumed to occur in an environment in which the reinforced concrete structure is installed;
A determination method comprising:
[Additional Note 2]
The method further includes an input step of receiving input of rust information related to the rust or rust traces of the reinforced concrete structure,
The judgment step includes a step of judging whether or not the reinforced concrete structure has rust or rust juice traces based on the rust information, and if it is judged that the reinforced concrete structure has rust or rust juice traces, judging that the reinforced concrete structure needs repair, and if it is judged that the reinforced concrete structure does not have the rust or rust juice traces, judging whether or not the reinforced concrete structure needs repair based on the deterioration stress-strain relationship and the assumed stress level.
[Additional Note 3]
The judgment method described in

Appendix

1 or 2, wherein the judgment step includes a step of judging whether the allowable stress level, obtained by dividing the design value of the stress level of the deteriorated reinforced concrete structure, as indicated by the deterioration stress-strain relationship, by the safety factor of the reinforced concrete structure, is equal to or greater than the assumed stress level assumed to occur in the environment in which the reinforced concrete structure is installed, and if it is determined that the allowable stress level is equal to or greater than the assumed stress level, judging that repair of the reinforced concrete structure is not necessary, and if it is determined that the allowable stress level is less than the assumed stress level, judging that repair of the reinforced concrete structure is necessary.
[Additional Note 4]
The deteriorated reinforced concrete structure is a deteriorated reinforced concrete structure of a first standard,
Further comprising a deterioration ratio calculation step,
The stress level calculation step includes a step of calculating a first healthy stress-strain relationship indicating a correspondence relationship between stress level and strain of the healthy reinforced concrete structure of the first standard, using a healthy model representing a healthy reinforced concrete structure that is the reinforced concrete structure of the first standard in which no deterioration has occurred,
The deterioration ratio calculation step includes a step of calculating a deterioration ratio, which is a ratio of a design value of a stress level of a deteriorated reinforced concrete structure of the first standard, which is indicated by the deteriorated stress-strain relationship, to a design value of a stress level of a healthy reinforced concrete structure of the first standard, which is indicated by the first healthy stress-strain relationship;
The stress calculation step includes a step of calculating a second healthy stress-strain relationship showing the correspondence relationship between the stress and strain of the healthy reinforced concrete structure of the second standard using a healthy model representing a healthy reinforced concrete structure of the second standard, which is similar in shape but different in size from the first standard, and calculating a value obtained by multiplying the allowable stress of the healthy reinforced concrete structure of the second standard, based on the healthy stress-strain relationship of the second standard, by the deterioration ratio as the allowable stress of the deteriorated reinforced concrete structure of the second standard;
A determination method described in any one of appendix 1 to 3, wherein the determination step includes a step of determining whether the allowable stress level of the deteriorated reinforced concrete structure of the second standard is equal to or greater than the expected stress level expected to occur in the environment in which the reinforced concrete structure of the second standard is installed.
[Additional Note 5]
The stress calculation step includes:
determining the size and number of meshes for constructing the degradation model by a finite element method;
constructing the degradation model by a finite element method using the size and the number of the meshes;
The method according to any one of claims 1 to 4, further comprising:
[Additional Note 6]
A determination device for determining whether or not a reinforced concrete structure that defines an internal space is required to be repaired, the device comprising: a reinforcing bar; and concrete covering the reinforcing bar.
a controller, the controller comprising:
Calculating a deterioration stress-strain relationship showing a correspondence relationship between stress and strain of the deteriorated reinforced concrete structure using a deterioration model representing the deteriorated reinforced concrete structure, which is the reinforced concrete structure in which the concrete covering on the predetermined surface on the internal space side has peeled off;
A determination device that determines whether or not repair of the reinforced concrete structure is necessary based on the deterioration stress-strain relationship and an expected stress level that is expected to occur in the environment in which the reinforced concrete structure is installed.
[Additional Note 7]
A non-transitory storage medium storing a program executable by a computer, the non-transitory storage medium storing the program causing the computer to execute the determination method described in any one of appended claims 1 to 5.

All publications, patent applications, and technologies described in this specification are incorporated by reference into this specification to the same extent as if each individual publication, patent application, and technology was specifically and individually indicated to be incorporated by reference.

The above-described embodiments have been described as representative examples, but it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present disclosure. Therefore, the present invention should not be construed as being limited to the above-described embodiments, and various modifications or alterations are possible without departing from the scope of the claims.

Reference Signs List 1, 1-1: Determination device 2: Reinforced concrete structure 2-A: Sound reinforced concrete structure 2-B: Deteriorated reinforced concrete structure 2a: Reinforcement 2b: Concrete 2c: Crack 2d: Separation 2e: Exposed reinforcement 11: Input section 12, 12-1: Stress calculation section 13, 13-1: Determination section 14: Output section 21: Top member 22: Side member 23: Bottom member 121: Cover element number setting section 122: Finite element model construction section 123, 123-1: Finite element analysis section 124, 124-1: Calculation section 125: Deterioration ratio calculation section 301: Computer 310: Processor 320: ROM
330 RAM
340 Storage 350 Input section 360 Output section 370 Communication interface 380 Bus

Claims

A method for determining whether or not a reinforced concrete structure that includes a reinforcing bar and concrete covering the reinforcing bar and defines an internal space is required, the method being performed by a determination device, comprising:
a stress intensity calculation step of calculating a deterioration stress-strain relationship showing a correspondence relationship between stress intensity and strain of the deteriorated reinforced concrete structure using a deterioration model representing the deteriorated reinforced concrete structure, which is the reinforced concrete structure in which the concrete covering on a predetermined surface on the internal space side has peeled off;
a determining step of determining whether or not the reinforced concrete structure needs repair based on the deterioration stress-strain relationship and an assumed stress intensity assumed to occur in an environment in which the reinforced concrete structure is installed;
A determination method comprising:
The method further includes an input step of receiving input of rust information related to the rust or rust traces of the reinforced concrete structure,
2. The method of claim 1, wherein the determination step includes a step of determining whether or not the reinforced concrete structure has the rust or rust traces based on the rust information, determining that the reinforced concrete structure needs repair if it is determined that the reinforced concrete structure has the rust or rust traces, and determining whether or not the reinforced concrete structure needs repair based on the deterioration stress-strain relationship and the assumed stress level if it is determined that the reinforced concrete structure does not have the rust or rust traces.
The judgment method according to claim 1 or 2, wherein the judgment step includes a step of judging whether or not the allowable stress level obtained by dividing the design value of the stress level of the deteriorated reinforced concrete structure, which is indicated by the deterioration stress-strain relationship, by the safety factor of the reinforced concrete structure is equal to or greater than the assumed stress level assumed to occur in the environment in which the reinforced concrete structure is installed, judging that the reinforced concrete structure does not need repair if it is judged that the allowable stress level is equal to or greater than the assumed stress level, and judging that the reinforced concrete structure needs repair if it is judged that the allowable stress level is less than the assumed stress level.
The deteriorated reinforced concrete structure is a deteriorated reinforced concrete structure of a first standard,
Further comprising a deterioration ratio calculation step,
The stress level calculation step includes a step of calculating a first healthy stress-strain relationship indicating a correspondence relationship between stress level and strain of the healthy reinforced concrete structure of the first standard, using a healthy model representing a healthy reinforced concrete structure that is the reinforced concrete structure of the first standard in which no deterioration has occurred,
The deterioration ratio calculation step includes a step of calculating a deterioration ratio, which is a ratio of a design value of a stress level of a deteriorated reinforced concrete structure of the first standard, which is indicated by the deteriorated stress-strain relationship, to a design value of a stress level of a healthy reinforced concrete structure of the first standard, which is indicated by the first healthy stress-strain relationship;
The stress calculation step includes a step of calculating a second healthy stress-strain relationship showing the correspondence relationship between the stress and strain of the healthy reinforced concrete structure of the second standard using a healthy model representing a healthy reinforced concrete structure of the second standard similar in shape but different in size from the first standard, and calculating a value obtained by multiplying the allowable stress of the healthy reinforced concrete structure of the second standard based on the healthy stress-strain relationship of the second standard by the deterioration ratio as the allowable stress of the deteriorated reinforced concrete structure of the second standard;
A determination method as described in claim 1 or 2, wherein the determination step includes a step of determining whether the allowable stress of the deteriorated reinforced concrete structure of the second standard is equal to or greater than the expected stress expected to occur in the environment in which the reinforced concrete structure of the second standard is installed.
The stress calculation step includes:
determining the size and number of meshes for constructing the degradation model by a finite element method;
constructing the degradation model by a finite element method using the size and the number of the meshes;
The method of claim 1 or 2, further comprising:
A determination device for determining whether or not a reinforced concrete structure that defines an internal space is required to be repaired, the device comprising: a reinforcing bar; and concrete covering the reinforcing bar.
a stress intensity calculation unit that calculates a deterioration stress-strain relationship that indicates a correspondence relationship between stress intensity and strain of the deteriorated reinforced concrete structure using a deterioration model that represents the deteriorated reinforced concrete structure, which is the reinforced concrete structure in which the concrete covering on a predetermined surface on the internal space side has peeled off;
a determination unit that determines whether or not the reinforced concrete structure needs repair based on the deterioration stress-strain relationship and an assumed stress intensity that is assumed to occur in an environment in which the reinforced concrete structure is installed;
A determination device comprising:
A program for causing a computer to execute the determination method according to claim 1 or 2.