Inter-story drift angle detection device and inter-story drift angle detection system

Abstract

The present invention provides an inter-story drift angle detection device and system that can detect deformation in any direction of the floor and ceiling plane (story plane), not limited to deformation of the column and beam structure, and can accurately detect the actual inter-story drift angle. [Solution] The present invention provides an inter-story drift angle detection device 100 comprising a vertical member 10 installed between the lower and upper floors of a building BL, and a gyro sensor 20 attached to the vertical member to detect changes in the inclination of the vertical member, wherein both ends of the vertical member are connected by a pin joint mechanism 30 to horizontal members that constitute the structure of the lower and upper floors. The present invention also provides an inter-story drift angle detection system 1 in which multiple inter-story drift angle detection devices 100 are installed on the building's plane.

Description

Technical Field

[0001] The present invention relates to an inter-story drift angle detection device and an inter-story drift angle detection system.

Background Art

[0002] Generally, when a structure such as a building is shaken by an earthquake or the like, a rectangular frame surrounded by columns and beams is schematically deformed into a parallelogram. If the deformation occurs while geometric factors such as the length and linearity of columns and beams remain maintained, the correlation between the displacement measured by a sensor installed on the building and the inter-story deformation of the building will be favorable, and the measured displacement and the inter-story deformation can be linearly approximated.

[0003] Using such a principle, for example, Patent Document 1 discloses a measurement system capable of measuring the situation with high accuracy even when displacement, particularly large inter-story displacement, occurs in a building due to shaking such as an earthquake. This measurement system uses a displacement measurement device including a vertical rod installed between a lower floor and an upper floor of a building, an elongated diagonal member obliquely installed between the vertical rod and the lower floor or the upper floor and capable of expanding and contracting in the longitudinal direction, and a measuring instrument that measures the expansion and contraction displacement of the diagonal member. Then, when the inter-story displacement derived based on the relationship with the inter-story displacement between the lower floor and the upper floor from the expansion and contraction displacement measured by the measuring instrument exceeds a reference value set based on a threshold for building damage, a warning regarding building damage is output.

[0004] There is also a known technology in which an acceleration sensor is directly attached to a column to detect vibration and inclination. For example, Patent Document 2 discloses a building damage degree determination system that can simply and quickly determine the damage degree of a building with high accuracy after an earthquake occurs. This damage degree determination system arranges MEMS-type acceleration sensors on the column bases of each floor of a building, calculates the inter-story drift angle θ, which is the change in vertical inclination angle with respect to the front-rear direction, when an earthquake occurs based on the detection results of the MEMS-type acceleration sensors, and directly monitors the inter-story drift angle θ to determine the building damage level, which is the damage degree of the building.

Prior Art Literature

Patent Literature

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-159601 [Patent Document 2] Japanese Patent Publication No. 2019-203713 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the prior art described in Patent Document 1 measures the axial displacement of the diagonal members due to expansion / sliding and calculates the inter-story displacement between the lower and upper floors. However, if there is deformation or shaking of the building in a direction different from the expansion / sliding direction (if the expansion / sliding direction is the X-axis-Y axis direction, then the different direction is the Z-axis direction), axial misalignment occurs, making it impossible to accurately detect the deformation, and thus limiting the measurement to the deformation of the column-beam structure.

[0007] Furthermore, in the prior art described in Patent Document 2, even if acceleration sensors are placed at the base of the columns, the columns themselves deform due to cracks, material yielding, bending, and indentation, especially during major earthquakes, and therefore cannot be kept in a straight line, and thus cannot be said to represent the inclination between layers of the structure (as will be described later, experiments have proven that the inclination of wooden columns is only about half the inter-story drift angle). In addition, the deformation is calculated by measuring acceleration and using the rigidity and mass of the building, but since the rigidity and mass of individual buildings cannot be accurately determined, it is not possible to accurately calculate the deformation. Moreover, the calculation method differs depending on the type of structure, such as wood or reinforced concrete, wall structure or rigid frame structure, so the scope of application is limited.

[0008] Therefore, the present invention was devised in view of these circumstances, and provides an inter-story drift angle detection device and inter-story drift angle detection system that can detect deformation in any direction of the floor and ceiling plane (story plane), not limited to deformation of the column and beam structure, and can accurately detect the actual inter-story drift angle. [Means for solving the problem]

[0009] To solve the above problems, an inter-story drift angle detection device is provided, which includes vertical members installed between the lower and upper floors of a building, and gyro sensors attached to the vertical members to detect changes in the inclination of the vertical members, with both ends of the vertical members connected by a pin joint mechanism to horizontal members that constitute the structure of the lower and upper floors. According to this, by providing vertical members attached between the lower and upper floors of a building by a pin joint mechanism, and gyro sensors attached to the vertical members to detect changes in their inclination, it is possible to provide an inter-story drift angle detection device that can detect deformation in any direction of the floor-ceiling plane (story plane), not just deformation of the column-beam structure, and can accurately detect the actual inter-story drift angle.

[0010] Furthermore, the pin joint mechanism may be characterized by comprising a first joint connected to a lower floor and a second joint connected to an upper floor, wherein the first joint has a receiving member attached to a horizontal member of the lower floor and having a recess for receiving the lower end of a vertical member, and an elastic member that biases the lower end of the vertical member downward, and the second joint has a fitting hole on its lower surface for inserting and fitting the upper end of a vertical member which is formed to be thinner than the body of the vertical member, and a flange on its upper surface for attachment to a horizontal member of the upper floor, and a holding member which is formed in a protruding shape so that the inserted upper end does not come into contact with the horizontal member of the upper floor. According to this, the structure consists of a first joint and a second joint, both of which have a pin joint mechanism. This prevents the vertical members from falling off even in the event of large vibrations or deformations, allowing for more accurate detection of the inter-story drift angle.

[0011] To solve the above problems, we can provide an inter-story drift angle detection system characterized by having multiple inter-story drift angle detection devices installed on the building's plan. According to this, by installing multiple inter-story drift angle detection devices on the building's plan, an inter-story drift angle detection system can be provided that can detect torsional deformation between the upper and lower floors of a building.

[0012] Furthermore, the system may be characterized by the installation of multiple inter-story drift angle detection devices along the diagonals of the building's plan. According to this method, by installing multiple inter-story drift angle detection devices along the diagonals of the building's plan, the maximum displacement of each side on the plan can be measured, and the torsional deformation of the upper and lower floors of the building can be detected more accurately. [Effects of the Invention]

[0013] As described above, the present invention provides an inter-story drift angle detection device and system that can detect deformation in any direction of the floor and ceiling plane (story plane), not limited to deformation of the column and beam structure, and can accurately detect the actual inter-story drift angle. [Brief explanation of the drawing]

[0014] [Figure 1] A schematic diagram of the inter-story drift angle detection device according to the first embodiment of the present invention. [Figure 2] Detailed diagram of the pin joint mechanism of a modified example 1 of the interlayer drift angle detection device according to the first embodiment of the present invention. [Figure 3] Detailed diagram of the pin joint mechanism of a modified example 2 of the interlayer drift angle detection device according to the first embodiment of the present invention. [Figure 4] A diagram showing the inter-story drift angle detection device of the first embodiment of the present invention being used in a building. [Figure 5] This figure shows the following cases in which the inter-story drift angle detection device of the first embodiment of the present invention is used in a building: (A) when one is used; (B) when two inter-story drift angle detection devices are used as an inter-story drift angle detection system and both detect the same displacement; (C) when two inter-story drift angle detection devices are used as an inter-story drift angle detection system and each detects a different displacement; and (D) when two inter-story drift angle detection devices are installed on opposite sides of the building's plane as an inter-story drift angle detection system and each shows a different displacement. [Figure 6] A diagram showing a test specimen used to verify the inter-story drift angle detection device according to the present invention. [Figure 7] This figure shows the verification results of a conventional inter-story drift angle detection device. [Figure 8] Figure (1) showing the verification results of the inter-story drift angle detection device according to the present invention. [Figure 9] Figure 2 shows verification results of the inter-story drift angle detecting device according to the present invention. MODE FOR CARRYING OUT THE INVENTION

[0015] Hereinafter, embodiments according to the present invention will be described with reference to the drawings. <First Embodiment> With reference to FIGS. 1 to 5, an inter-story drift angle detecting device 100 according to the present embodiment will be described. The inter-story drift angle detecting device 100 is attached between a lower floor and an upper floor of a building BL. The building BL is configured of a framework portion and a structural body (skeleton) of the building that supports forces applied to the building BL, and FIG. 1 shows a rigid frame structure having a horizontal member CB and a column PL as the skeleton. However, the building BL is not limited to a rigid frame structure, and may be a building or a civil engineering structure configured of a braced structure, a wall-type structure, a truss structure, or a shell structure. In addition, although only one floor is shown in the drawing, one or more lower floors or foundation structures may be further provided below the illustrated lower floor, and one or more upper floors or roof structures may be further provided above the illustrated upper floor. In the present specification, the horizontal member CB refers to a structural member horizontally laid in the framework of a building, and includes not only beams and girders but also slabs in reinforced concrete structures

[0016] The inter-story drift angle detecting device 100 is a device for detecting horizontal displacement (inter-story displacement) generated between floors of upper and lower floors when a skeleton formed of the horizontal member CB and the column PL is deformed by an external force such as an earthquake or strong wind. The inter-story drift angle detecting device 100 includes a vertical member 10 attached between a lower floor and an upper floor of the building BL, and a gyro sensor 20 attached to the vertical member 10 and detecting a change in inclination of the vertical member 10, and both ends of the vertical member 10 are connected by pin joint mechanisms 30 to the horizontal members CB constituting skeletons of the lower floor and the upper floor.

[0017] The vertical members 10 are rod-shaped members that are slightly shorter than the length (height) of the column PL. They are sturdy enough to stand on their own but do not contribute to the structure of the building BL. If they are made of aluminum, the small diameter is about length / 100, and if they are made of wood, the small diameter is about length / 50. In the case of a typical house, a square timber with a width of about 40 mm may also be used. The material of the vertical members 10 is not particularly limited and can be wood, metal such as aluminum, or plastic. The horizontal cross-section is not particularly limited and can be square, round, L-shaped, hollow / solid, etc. Also, while a straight rod shape is preferable for the vertical members 10, it is not a problem if they are slightly curved / bent as they are members that capture changes in inclination.

[0018] While it is preferable for the vertical members 10 to be installed perpendicular (vertically) to the horizontal members CB, the inter-story drift angle detection device 100 detects changes in inclination, so it is not necessary for them to be installed strictly perpendicular (vertically). In reinforced concrete structures, it is preferable to install the vertical members 10 between beams, as this results in a smaller effective height, rather than between slabs.

[0019] The gyro sensor 20 is a sensor that detects the angle (attitude) of an object in at least three axes. The detection method (mechanical, fluid, optical, etc.) of the gyro sensor 20 is not limited as long as it detects the object. The gyro sensor 20 is firmly attached to the vertical member 10 so that it does not loosen, shift, or fall off. Its mounting position is not particularly limited and may be in the middle, upper end, or lower end of the vertical member 10. In this way, the gyro sensor 20 detects the change in the inclination of the vertical member 10, i.e., the inter-story drift angle, before and after inter-story displacement caused by earthquakes or the like.

[0020] The pin joint mechanism 30 connects the ends of the horizontal members CB and vertical members 10 that constitute the lower and upper floor structures using a joining method that does not generate or transmit bending moments at the joint. Various joining methods are possible for the pin joint mechanism 30, but for example, as shown in Figure 2 illustrating Modification 1, it can be composed of a first joint connected to the lower floor and a second joint connected to the upper floor. The first joint of this pin joint mechanism 30 has a receiving member attached to the upper surface of the horizontal member CB of the lower floor for receiving the lower end of the vertical member 10, and a receiving member attached to the lower surface of the horizontal member CB of the upper floor for receiving the upper end of the vertical member 10. The second joint has a cylindrical member attached to the lower surface of the horizontal member CB of the upper floor for receiving the upper end of the vertical member 10, and has an elastic member inside that contracts when the upper end of the vertical member 10 is installed and biases it from above after installation (normally).

[0021] Furthermore, the pin joint mechanism 30 can be composed of a first joint and a second joint, as shown in Figure 3, which illustrates a modified example of the pin joint mechanism 30. In this pin joint mechanism 30, the first joint has a receiving member attached to the upper surface of the horizontal member CB of the lower floor and having a recess for receiving the lower end of the vertical member 10, and an elastic member that biases the lower end of the vertical member 10 downward. The second joint has a so-called cone-shaped holding member, which has a fitting hole on its lower surface into which the upper end of the vertical member 10, which is formed to be thinner than the body of the vertical member 10, is inserted and fitted, and a flange on its upper surface for attachment to the lower surface of the horizontal member CB of the upper floor, and is formed in a shape that protrudes so that the inserted upper end does not come into contact with the horizontal member CB of the upper floor. The holding member may also have a rotating ball attached to the fitting hole that swings through the upper end of the thinly formed vertical member 10 to smooth movement in any direction.

[0022] In the pin joint mechanism 30 of Modification 1, the vertical member 10 will not detach from the pin joint mechanism 30 if the interlayer drift angle is about 1 / 10 (Rad), but it may detach if the interlayer drift angle exceeds that. Also, the elastic member (spring) housed inside the cylindrical member cannot be used because, when installing it, the upper end of the vertical member 10 needs to be pressed against the inside of the cylindrical member with the inside facing upwards.

[0023] In contrast, in the pin joint mechanism 30 of Modified Example 2, the upper end of the vertical member 10 is deeply inserted through a fitting hole into a cone shape that protrudes significantly downward, reaching near the lower surface of the upper floor. Therefore, even if a large inter-story displacement occurs, the vertical member 10 will not fall out of the pin joint mechanism 30. Furthermore, since the elastic member (spring) that connects the lower end of the vertical member 10 to the lower part of the vertical member 10 and biases the lower end of the vertical member 10 downward with tensile force does not need to be removed, an elastic member that biases downward with a large force can be used. Therefore, the pin joint mechanism 30 of Modified Example 2 can be used even in seismic isolation layers where large displacements may occur, and the inter-story drift angle can be accurately detected even with large inter-story displacements. The connection between the first joint and the upper surface of the horizontal member CB of the lower floor, and the connection between the second joint and the lower surface of the horizontal member CB of the upper floor are firmly made using double-sided tape or screws.

[0024] As shown in Figure 4, the inter-story drift angle detection device 100 transmits the detected values ​​to a monitoring device or monitoring center using an information and communication device. Known technologies are used for this information and communication device. For example, the inter-story drift angle detection devices 100 installed on each floor and the monitoring device may be wired together with a LAN cable via a POE (Power over Ethernet) hub to supply power to the gyro sensor 20 and transmit the detected values ​​to the monitoring device, etc., through the communication function. Alternatively, a device (logger) that supplies power to the gyro sensor 20 and has a wireless communication function may be installed near the inter-story drift angle detection devices 100 installed on each floor, and the detected values ​​may be transmitted to the monitoring device, etc., through wireless communication.

[0025] These devices and monitoring devices store information such as the floor on which each device is installed, the floor height of that floor, the length of the vertical members 10, and the structure of the building BL. Based on the inter-story drift angle detected by the gyro sensor 20, the inter-story displacement of the building BL can be determined. Furthermore, these devices and monitoring devices may perform a risk assessment based on the determined inter-story displacement according to the building structure.

[0026] Thus, by providing a vertical member 10 attached between the lower and upper floors of the building BL by a pin joint mechanism 30, and a gyro sensor 20 attached to the vertical member 10 to detect changes in the inclination of the vertical member 10, it is possible to provide an inter-story drift angle detection device 100 that can detect deformation in any direction of the floor-ceiling plane (story plane), not limited to deformation of the column-beam structure, and can accurately detect the actual inter-story drift angle.

[0027] One inter-story drift angle detection device 100 is installed on each floor (each level), preferably two or more. When multiple inter-story drift angle detection devices 100 are installed on each floor, these multiple inter-story drift angle detection devices 100 are collectively referred to as the inter-story drift angle detection system 1. When one inter-story drift angle detection device 100 is installed on each floor, it is preferable that the inter-story drift angle detection device 100 is installed in the center of the floor plan of the building BL, where it is considered to represent a typical floor displacement. Furthermore, it is preferable to install two (or more) inter-story drift angle detection devices 100 on each floor rather than just one. Moreover, when two (or more) inter-story drift angle detection devices 100 are installed on each floor, it is preferable that these inter-story drift angle detection devices 100 are installed on the diagonals of the floor plan of the building BL.

[0028] Referring to Figure 5, we will explain what information can be detected depending on the number of inter-story drift angle detection devices 100 installed on each floor. Figure (A) shows that when one inter-story drift angle detection device 100 is installed in the center of the floor plan, the inter-story displacement occurred in the north-northeast direction, that is, the gyro sensor 20 tilted in the north-northeast direction. This can be considered a typical inter-story displacement on this floor, and is interpreted as the upper floor having shifted (displaced) in the north-northeast direction relative to the lower floor. However, with only one inter-story drift angle detection device 100, it is unclear whether the entire structure truly shifted in the north-northeast direction.

[0029] Figure (B) shows that two inter-story drift angle detection devices 100 are installed in the upper right and lower left corners of the floor plan (not on the diagonal), and that the two inter-story drift angle detection devices 100 show the same magnitude and the same north-northeast direction inter-story displacement. In other words, in this inter-story drift angle detection system 1, the inter-story drift angle detection device 100 installed in the southwest corner and the inter-story drift angle detection device 100 installed in the northeast corner are displaced in the same north-northeast direction with the same magnitude at different locations, thus detecting that the upper floor has shifted parallel to the lower floor as a whole in the north-northeast direction. In this way, by installing multiple inter-story drift angle detection devices 100 on the building plan, the deformation of the upper and lower floors of the building can be accurately detected.

[0030] Figure (C) shows that two inter-story drift angle detection devices 100 are installed in the upper right and lower left corners of the floor plan (not on the diagonal), and that the two inter-story drift angle detection devices 100 have detected inter-story displacements of different magnitudes and directions. In other words, in this inter-story drift angle detection system 1, the inter-story drift angle detection device 100 installed in the southwest corner was displaced in the north-northeast direction, and the inter-story drift angle detection device 100 installed in the northeast corner was displaced in the northeast direction by about half the magnitude. Therefore, it was detected that the upper floors experienced inter-story displacement with both horizontal displacement and rotational torsion relative to the lower floors. In this way, by installing multiple inter-story drift angle detection devices 100 on the building plan, torsional deformation between the upper and lower floors of a building can be detected.

[0031] Figure (D) shows that two inter-story drift angle detection devices 100 are installed in the upper right and lower left corners of the floor plan (diagonally opposite locations), and that the two inter-story drift angle detection devices 100 have detected inter-story deformations of different magnitudes and directions. In other words, in this inter-story drift angle detection system 1, the inter-story drift angle detection device 100 installed in the southwest corner was displaced in the north-northwest direction, and the inter-story drift angle detection device 100 installed in the northeast corner was displaced in the south-southeast direction with the same magnitude. Therefore, it was detected that the upper floors experienced torsional inter-story displacement centered approximately on the center of the floor plan relative to the lower floors. In this way, by installing multiple inter-story drift angle detection devices 100 on the diagonals of the building plan, the maximum displacement of each side on the floor plan can be measured, and the torsional deformation of the upper and lower floors of the building can be detected more accurately.

[0032] <Verification of the inter-story drift angle detection device of this application> Referring to Figures 6 to 9, the present invention will be explained in which inter-story drift angle is accurately detected. Figure 6 shows an inter-story displacement testing device installed in the applicant's facility. This inter-story displacement testing device has a robust structure (framework) composed of upper and lower horizontal members TCBs, which are considered to be the upper and lower floors, two columns TPL that support them, and diagonal members TBR installed between the columns TPL. This inter-story displacement testing device tests the inter-story displacement only in the column-beam structure plane (parallel to the plane of the paper) consisting of these horizontal members TCBs and columns TPL, and inter-story displacement outside this column-beam structure plane, i.e., in the direction perpendicular to the plane of the paper, is ignored.

[0033] In this inter-story displacement testing apparatus, one inter-story deformation angle detection device 100 is attached to the right vicinity of the right column TPL. The vertical members 10 are made of 40x40 aluminum, and their upper and lower ends are loosely screwed to the horizontal members TCB, respectively, and are joined to the horizontal members TCB by a pin joint mechanism 30 configured to allow rotation within the column-beam structure. The gyro sensor 20 (hereinafter also referred to as sensor A in the figure) is attached near the upper end of the vertical member 10 to detect changes in the inclination of the vertical member 10 within the column-beam structure. For comparison with the detection accuracy of the gyro sensor 20 of the present invention, a sensor with the same performance as the gyro sensor 20 (hereinafter referred to as sensor B, including in the figure) was installed at the column TPL (mid-height position). Furthermore, a displacement meter (not shown) for accurately measuring the inter-story displacement of this inter-story displacement testing apparatus was also installed separately.

[0034] Figure 7 shows the error between the displacement gauge and the B sensor when the B sensor is attached to the column TPL as in the conventional technique. According to this, at all inter-story drift angles (1 / 150 to 1 / 15 Rad in this figure), the B sensor can only detect about half the displacement compared to the accurate displacement shown by the displacement gauge.

[0035] On the other hand, Figure 8 shows that for the same inter-story drift angle of 1 / 150 to 1 / 15, sensor A detects inter-story displacement with high accuracy, with an error of less than 5% compared to the accurate displacement shown by the displacement gauge, and especially when the inter-story drift angle is 1 / 75 Rad or greater, the error is less than 1%. Note that when the inter-story drift angle is small (for example, 1 / 450 or 1 / 300 Rad), the error may exceed 10%, but since this is an error of only a few millimeters in terms of displacement, it is considered within an acceptable range. Based on these results, sensor B, attached to the column TPL, cannot accurately detect the inter-story displacement of the horizontal member TCB due to the deformation of the column TPL itself, but sensor A, attached to the vertical member 10 joined to the horizontal member TCB by the pin joint mechanism 30, can accurately detect the inter-story drift angle and, consequently, the inter-story displacement.

[0036] Furthermore, Figure 9 shows the test results obtained using an inter-story displacement testing device different from the one shown in Figure 6. This inter-story displacement testing device is equipped with an inter-story drift angle detection device 100, as well as a pencil that tracks the displacement of the horizontal structural members TCBs corresponding to the upper floor relative to the horizontal structural members TCBs corresponding to the lower floor, in a two-dimensional direction on the floor plane. In other words, the trajectory traced by this pencil accurately represents the inter-story displacement of the upper floor relative to the lower floor.

[0037] This figure shows the inter-story displacement trajectories drawn by a pencil and the inter-story displacement trajectories detected by the gyro sensor 20 when vibrations are applied to this inter-story displacement testing device for 1 cycle and 10 cycles. It can be said that the inter-story displacement trajectories drawn by the pencil and the inter-story displacement trajectories detected by the gyro sensor 20 are almost identical for 1 cycle and 10 cycles. Therefore, the inter-story deformation angle detection device 100 can accurately detect the inter-story deformation angle and, consequently, the inter-story displacement.

[0038] The inter-story drift angle detection device and inter-story drift angle detection system according to the present invention are measuring instruments that measure changes in their own tilt regardless of the structure to which they are attached, and therefore can be applied to all structural types and forms, regardless of the rigidity or mass of the building.

[0039] It should be noted that the present invention is not limited to the exemplary embodiments, and can be implemented in configurations that do not depart from the content described in each claim. In other words, although the present invention is illustrated and described in particular with respect to specific embodiments, those skilled in the art can make various modifications to the embodiments described above in terms of quantity and other detailed configurations without departing from the scope of the technical idea and objectives of the present invention. [Explanation of symbols]

[0040] 1. Inter-story drift angle detection system 100 Interstory Deformation Angle Detection Device 10 vertical members 11 Lower end of vertical member 12. Upper end of vertical member 13 Upper end of vertical member 20 Gyroscope Sensor 30-pin connection mechanism 31 First Joining Member 311 Receiving member 312 recess 313 Elastic members 32 Second Joining Member 321 Fitting hole 322 Flange 323 Retaining member BL Building CB horizontal member PL pillar

Claims

1. Vertical members installed between the lower and upper floors of a building, A gyro sensor is attached to the vertical member to detect changes in the tilt of the vertical member, Equipped with, Both ends of the vertical members are connected by a pin joint mechanism to the horizontal members that make up the structure of the lower and upper floors. Inter-story drift angle detection device.

2. The pin joint mechanism consists of a first joint that connects to the lower floor and a second joint that connects to the upper floor. The first joint has a receiving member that is attached to the horizontal member of the lower floor and has a recess for receiving the lower end of the vertical member, and an elastic member that biases the lower end of the vertical member downward. The inter-story deformation angle detection device according to claim 1, characterized in that the second joint has a fitting hole on its lower surface into which the upper end of the vertical member, which is formed to be thinner than the main body of the vertical member, is inserted and fitted, and a flange on its upper surface for attachment to the horizontal member of the upper floor, and a retaining member formed in a shape that protrudes so that the inserted upper end does not come into contact with the horizontal member of the upper floor.

3. An inter-story drift angle detection system characterized in that a plurality of inter-story drift angle detection devices according to claim 1 or claim 2 are installed on the building's plan.

4. The inter-story drift angle detection system according to claim 3, characterized in that multiple inter-story drift angle detection devices are installed on the diagonals of the building's plan.

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