Method and system for monitoring steel structure building

Abstract

To specify a damage form and a damage place of a member level of a steel structure building, and to accurately monitor damage.SOLUTION: A strain detector is directly provided on a surface of a column and a beam of a multi-story steel structure building having a steel column and a steel beam, (1) First information on yield and local buckling of the column and (2) second information on buckling, cracking, breaking, and a neutral axis position in combination with a slab of the beam are obtained, a degree of damage of the steel column and beam is evaluated based on the first information and the second information, and determination on restoration is made based on the evaluation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a monitoring method and a monitoring system for a steel structure building. [Background technology]

[0002] In particular, in Japan, a country prone to earthquakes, once a building is damaged by an earthquake, it is important to quickly determine what measures should be taken (whether restoration is necessary, whether restoration is possible, etc.) depending on the extent of the damage.

[0003] Generally, acceleration sensors or MEMS (Micro Electro Mechanical Systems) sensors are installed on the necessary floors of a building to detect the response inter-story displacement and floor response acceleration, and damage to the building is assessed by analyzing these.

[0004] On the other hand, it is also known that damage to a building can be evaluated by installing strain sensors in the column sections, calculating inter-story displacements based on strain values ​​measured at each time t for a specified cross section of the column's elastic behavior region, and analyzing these (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-134274 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even if the response story deformation angle during an earthquake is known, in steel structure buildings, the components to be inspected for damage are often covered with interior finishes or fireproof coatings, and it is not possible to determine the location and state of damage by visual inspection or external appearance.

[0007] Furthermore, although it is possible to identify a "layer" where many components have experienced damage such as "material yielding" or "buckling," where the degree of damage is highly correlated with the rotational amplitude of the component end, it is not possible to identify more specific damaged areas such as the "frame" or "components" within that layer. Furthermore, the "cracks" and "fractures" that occur due to the repeated stress history of steel members are "cumulative damage" that does not depend solely on the magnitude of the response inter-story deformation angle, and are therefore difficult to detect using monitoring systems that use accelerometers or conventional strain gauges.

[0008] Therefore, a main object of the present invention is to provide an accurate damage monitoring method and monitoring system that can identify the damage type and location at the component level of a steel structure building. [Means for solving the problem]

[0009] In order to solve the above problems, the following aspects are provided. (First aspect) A method for monitoring a multi-story steel structure building having steel columns and beams, comprising: Strain detectors are provided directly on the surfaces of at least the columns and beams, Based on the dynamic strain signal from the strain detector during an earthquake, (1) first information regarding yielding and local buckling for the column; (2) Second information regarding the beam, including buckling, cracking, fracture, and neutral axis location in combination with the slab; and assessing the extent of damage to the steel columns and beams based on the first information and the second information; Making a decision regarding recovery based on said evaluation; A monitoring method for a steel structure building.

[0010] (Second aspect) A method for monitoring a multi-story steel structure building having steel columns and beams, comprising: Strain detectors are provided directly on the surfaces of at least the columns and beams, Accelerometers are installed on the floors of the floors. During an earthquake Based on the dynamic strain signal from the strain detector, (1) first information regarding yielding and local buckling for the column; (2) Second information regarding the beam, including buckling, cracking, fracture, and neutral axis location in combination with the slab; Based on a maximum response acceleration signal from the accelerometer, (3) Third information on the building response behavior, including maximum and time history story displacements of the target floor; and assessing the degree of damage to the steel columns and beams and the response behavior of the building based on the first information, the second information, and the third information; Making a decision regarding recovery based on said evaluation; A monitoring method for a steel structure building.

[0011] (Third aspect) A monitoring system for a multi-story steel structure building having steel columns and beams, comprising: Strain detectors directly provided on the surfaces of at least the columns and beams; Based on the dynamic strain signal from the strain detector during an earthquake, (1) first information regarding yielding and local buckling for the column; (2) Second information regarding the beam, including buckling, cracking, fracture, and neutral axis location in combination with the slab; an information acquisition unit for acquiring the an evaluation unit that evaluates the degree of damage to the steel columns and beams based on the first information and the second information, and configuring the system to make a decision regarding recovery based on the evaluation. A monitoring system for steel structure buildings.

[0012] (Fourth aspect) A monitoring system for a multi-story steel structure building having steel columns and beams, comprising: Strain detectors directly provided on the surfaces of at least the columns and beams; an accelerometer installed on the floor of the floor; During an earthquake Based on the dynamic strain signal from the strain detector, (1) first information regarding yielding and local buckling for the column; (2) Second information regarding the beam, including buckling, cracking, fracture, and neutral axis location in combination with the slab; Based on a maximum response acceleration signal from the accelerometer, (3) Third information on the building response behavior, including maximum and time history story displacements of the target floor; an information acquisition unit for acquiring the an evaluation unit that evaluates the degree of damage to the steel columns and beams and the response behavior of the building based on the first information, the second information, and the third information; and determining whether the recovery is necessary based on the evaluation. A monitoring system for steel structure buildings. [Effects of the Invention]

[0013] According to the present invention, it is possible to identify the damage type and location at the component level of a steel structure building, and to perform accurate damage monitoring. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view for explaining an example of a steel structure building and an installation location of a detector. [Figure 2] FIG. 10 is a cross-sectional view of an example of installation of a strain detector on a beam. [Figure 3] FIG. 10 is a cross-sectional view of an example of installation of a strain detector on a pillar. [Figure 4] FIG. 2 is a diagram illustrating an outline of information obtained based on detection data from a strain detector. [Figure 5] 1 is a flowchart of an example monitoring system. [Figure 6] 10 is a flowchart of an example of a determination procedure of the monitoring system. DETAILED DESCRIPTION OF THE INVENTION

[0015] Next, an embodiment of the present invention will be described. Note that this embodiment is merely an example of the present invention, and the scope of the present invention is not limited to the scope of this embodiment.

[0016] (First embodiment) The present invention relates to a method and device for monitoring earthquake motions in a multi-storey steel structure building X having steel columns and beams.

[0017] For example, as shown in the partial view of a steel structure building in FIG. 1, the steel structure building in the embodiment has four or more columns 10 and beams 20 spanning these columns, and is a steel structure building of two or more floors, for example, five or more floors. When in use, floor slabs 30 are installed, and the columns 10 and beams 20 are usually used covered with covering bodies (not shown) such as fire-resistant materials and exterior cladding.

[0018] In this embodiment, strain sensors 40 are provided directly on the surfaces of at least the steel columns 10 and steel beams 20, and the columns 10 and beams 20 together with the strain sensors 40 are covered by a covering (not shown).

[0019] The installation location and portion of the strain detector 40 can be selected as appropriate, but can be selected mainly from portions of the steel structure building X where damage is expected or portions that are effective for detecting damage.

[0020] In the illustrated embodiment, as also shown in Figures 2 and 3, strain detectors 40 can be installed at appropriate intervals along the length on the inner surface of the flange of the beam 20 and on the outer surface of the hollow column 10. Furthermore, since strain may occur at the joint between the column and beam as shown in Figure 4(e), it is effective to install strain detectors 40 at the joint between the column 10 and the beam 20. Furthermore, it is also effective to install strain detectors 40 at the base of the column.

[0021] The dynamic strain signals from each strain detector 40 are input into the strain measurement unit that constitutes the information acquisition section 50 shown in Figure 5, and the degree of damage to the steel columns and beams is evaluated by the evaluation section 52. Based on the evaluation results, decisions and instruction information 54 regarding restoration are transmitted to the building owner or manager.

[0022] The dynamic strain signal from the strain detector 40 can be applied to obtain a variety of basic information. For example, as shown in Figure 4, this basic information can include (a) inter-story displacement and column shear force, (b) balance of column-beam bending stress, (c) position of the column inflection point, (d) position of the beam neutral axis, (e) strain distribution in the beam end flange, and (f) bending stress around the beam weak axis.

[0023] This type of basic information is (1) First information on columns regarding yielding and local buckling, (2) Secondary information for beams regarding buckling, cracking, fracture, and neutral axis location in composites with slabs; can be used as the basis for

[0024] Then, based on the first information and the second information, the evaluation unit 52 evaluates the degree of damage to the steel columns and beams. Based on the assessment, a decision regarding recovery is made.

[0025] For example, columns are evaluated based on classification or grading into cases where yielding or local buckling is in a minor state and a major state. Additionally, beams can be evaluated based on classification or grading into minor and major states of buckling, cracking, fracture, and neutral axis position in the slab composite.

[0026] For this evaluation, structural information XI regarding the structure of the steel structure building X can also be used as a basis, as shown in FIG. As mentioned above, the structural information XI can be used to select the installation location and portion of the strain detector 40. Reference numeral 56 denotes a strain detector installation selection unit.

[0027] According to the above embodiment, strain detectors are installed directly on the surfaces of the columns and beams of a steel structure building, and information is acquired based on dynamic strain signals from the strain detectors during an earthquake, making it possible to appropriately identify the damage type and location at the component level (columns or beams), and perform accurate damage monitoring.

[0028] As shown in the outline flow in Figure 6, immediately after an earthquake occurs, information is obtained based on dynamic strain signals from strain detectors to identify the type and location of damage at the component level (columns or beams), and the level of emergency risk is determined based on this, as well as the degree of damage to the exterior surfaces such as the interior, exterior, and ceiling, the tilt angle of the entire building, and information from measurements using accelerometers, which will be described next, to determine the degree of damage.

[0029] If necessary, the aforementioned coating can be removed to directly investigate the damage pattern at the member level (column or beam). Then, the extent of the damage is classified and assessed, for example, whether restoration is impossible, restoration is required, or restoration is not required. If restoration is required or not required, a restoration plan is drawn up, restoration and repair work is carried out, and continued use is ensured. If restoration is not possible, the structure will be dismantled and removed.

[0030] (Second embodiment) An accelerometer is installed on the floor of the building, and based on the maximum response acceleration signal from this accelerometer, (3) It is desirable to obtain third information on the response behavior of the building, including the maximum and time history of story displacements of the target floor.

[0031] For example, as shown in FIG. 1, an accelerometer 42 may be provided on the floor surface, such as a slab 30, of a building floor. In this case, it is desirable to provide an accelerometer 42 on the floor surface, for example, the slab 30, of the adjacent floor. The location of the accelerometer 42 relative to the slab 30 can be selected as appropriate, for example, in the vicinity of the column 10 . Although it is possible to install the accelerometer 42 on the finished floor in addition to directly installing it on the slab 30, it is preferable to install the accelerometer 42 directly on the slab 30 because this is prone to introducing detection errors.

[0032] As the accelerometer, a known accelerometer, for example, a MEMS (Membrane Electromechanical Systems) sensor, can be used. Based on the signal from the accelerometer 42, the response story displacement and floor response acceleration of the target floor are detected and analyzed to obtain information for damage assessment of the building.

[0033] In this case, in addition to the first embodiment, it is desirable to obtain (3) third information regarding the response behavior of the building, including the maximum and time-history story displacements of the target floor. Then, based on the first information, the second information, and the third information, the degree of damage to the steel columns and beams and the response behavior of the building can be evaluated, and a decision regarding restoration can be made based on the evaluation. FIG. 5 shows a configuration in which the accelerometer 42 is incorporated.

[0034] Damage information for steel structures or the building itself can be obtained based on not only the maximum and time history inter-story displacement of the target floor, but also the maximum response acceleration of each floor surface, the maximum and time history inter-story deformation of each floor calculated based on the maximum response acceleration records of each floor surface, the input seismic motion to the superstructure calculated based on acceleration records at fixed positions of the superstructure such as the first floor, and the dynamic interaction effect calculated based on acceleration records on the free ground surface.

[0035] (About the benefits etc.) According to the first embodiment, damage to components can be detected and evaluated without visual inspection or appearance inspection if necessary by evaluating the damage state based on dynamic strain detection data.

[0036] In comparison with conventional examples, in steel structure buildings that have only implemented a monitoring system using accelerometers, attention is focused on the response inter-story deformation angle obtained by integrating the measurement results from the accelerometers during an earthquake, and it is possible to identify "stories" that contain many members that have suffered damage such as "material yielding" or "buckling," where the degree of damage is highly correlated with the rotational amplitude of the member ends, based on the logic that the story with a large response inter-story deformation angle contains members with significant damage. However, it is not possible to identify more detailed parts such as "framework" or "members" within that story. Furthermore, the "cracks" and "fractures" that occur due to the repeated history of steel components are "cumulative damage" that does not depend solely on the magnitude of the response inter-story deformation angle, and are therefore difficult to detect using conventional monitoring systems that use accelerometers.

[0037] In contrast, in the embodiment, damage conditions can be detected at the "component" level from detection data based on strain detectors installed in the "component" itself, making it possible to identify more specific points such as "framework" or "component" rather than "story." In addition, dynamic strain data can be detected as cumulative strain values ​​and "cumulative damage" can be evaluated using fatigue curves based on Miner's law, etc., making it possible to detect damage such as "cracks" and "fractures" in addition to "material yielding" and "buckling."

[0038] In steel structure buildings that only implement conventional monitoring systems using accelerometers, component damage inspections are carried out visually and externally, which means that detailed investigations to identify damage require large-scale and long-term work, placing a heavy burden on building owners and managers.

[0039] In contrast, in the embodiment, dynamic strain detection data is utilized to perform time history response analysis at the component level with increased precision, making it possible to identify areas and parts with significant damage, thereby limiting the scope of detailed investigation and reducing the cost and time required for the investigation.

[0040] Furthermore, in steel-structure buildings that only implement monitoring systems using conventional accelerometers, when assessing earthquake damage based on the response inter-story deformation angle obtained by double-integrating the measurement results from the accelerometers during an earthquake, highly accurate time synchronization is required, which tends to reduce the accuracy of earthquake damage assessment in low-rise buildings.

[0041] In contrast, in the embodiment, time synchronization is not required and the damage state can be grasped directly from detection data based on strain detectors installed on the "components" themselves, making it possible to perform highly accurate damage assessment even in low-rise buildings. [Industrial Applicability]

[0042] The present invention can be used for general monitoring of steel structure buildings having not only low floors but also high floors. [Explanation of symbols]

[0043] X...steel structure building, 10...column, 20...beam, 30...slab, 40...strain detector, 42...accelerometer, 50...information acquisition unit, 52...evaluation unit, 54...judgment and instruction information regarding restoration, 56...Strain detector installation selection section.

Claims

1. A method for monitoring a multi-story steel structure building having steel columns and beams, comprising: Strain detectors are provided directly on the surfaces of at least the columns and beams, Based on the dynamic strain signal from the strain detector during an earthquake, (1) first information regarding yielding and local buckling for the column; (2) Second information regarding the beam, including buckling, cracking, fracture, and neutral axis location in combination with the slab; and assessing the extent of damage to the steel columns and beams based on the first information and the second information; Making a decision regarding recovery based on said evaluation; A monitoring method for a steel structure building.

2. A method for monitoring a multi-story steel structure building having steel columns and beams, comprising: Strain detectors are provided directly on the surfaces of at least the columns and beams, Accelerometers are installed on the floors of the floors. During an earthquake Based on the dynamic strain signal from the strain detector, (1) first information regarding yielding and local buckling for the column; (2) Second information regarding the beam, including buckling, cracking, fracture, and neutral axis location in combination with the slab; Based on a maximum response acceleration signal from the accelerometer, (3) Third information on the response behavior of the building, including the maximum and time history story displacements of the target floor; and assessing the degree of damage to the steel columns and beams and the response behavior of the building based on the first information, the second information, and the third information; Making a decision regarding recovery based on said evaluation; A monitoring method for a steel structure building.

3. A monitoring system for a multi-story steel structure building having steel columns and beams, comprising: Strain detectors directly provided on the surfaces of at least the columns and beams; Based on the dynamic strain signal from the strain detector during an earthquake, (1) first information regarding yielding and local buckling for the column; (2) Second information regarding the beam, including buckling, cracking, fracture, and neutral axis location in combination with the slab; an information acquisition unit for acquiring the an evaluation unit that evaluates the degree of damage to the steel columns and beams based on the first information and the second information, and configuring the system to make a decision regarding recovery based on the evaluation. A monitoring system for steel structure buildings.

4. A monitoring system for a multi-story steel structure building having steel columns and beams, comprising: Strain detectors directly provided on the surfaces of at least the columns and beams; an accelerometer installed on the floor of the floor; During an earthquake Based on the dynamic strain signal from the strain detector, (1) first information regarding yielding and local buckling for the column; (2) Second information regarding the beam, including buckling, cracking, fracture, and neutral axis location in combination with the slab; Based on a maximum response acceleration signal from the accelerometer, (3) Third information on the response behavior of the building, including the maximum and time history story displacements of the target floor; an information acquisition unit for acquiring the an evaluation unit that evaluates the degree of damage to the steel columns and beams and the response behavior of the building based on the first information, the second information, and the third information; and determining whether the recovery is necessary based on the evaluation. A monitoring system for steel structure buildings.

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